src/compiler/translator/ParseContext.cpp - platform/external/angle - Git at Google

 //
 // Copyright (c) 2002-2014 The ANGLE Project Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //

 #include "compiler/translator/ParseContext.h"

 #include <stdarg.h>
 #include <stdio.h>

 #include "common/mathutil.h"
 #include "compiler/preprocessor/SourceLocation.h"
 #include "compiler/translator/Cache.h"
 #include "compiler/translator/IntermNode_util.h"
 #include "compiler/translator/ValidateGlobalInitializer.h"
 #include "compiler/translator/ValidateSwitch.h"
 #include "compiler/translator/glslang.h"
 #include "compiler/translator/util.h"

 namespace sh
 {

 ///////////////////////////////////////////////////////////////////////
 //
 // Sub- vector and matrix fields
 //
 ////////////////////////////////////////////////////////////////////////

 namespace
 {

 const int kWebGLMaxStructNesting = 4;

 bool ContainsSampler(const TStructure *structType);

 bool ContainsSampler(const TType &type)
 {
     if (IsSampler(type.getBasicType()))
     {
         return true;
     }
     if (type.getBasicType() == EbtStruct)
     {
         return ContainsSampler(type.getStruct());
     }

     return false;
 }

 bool ContainsSampler(const TStructure *structType)
 {
     for (const auto &field : structType->fields())
     {
         if (ContainsSampler(*field->type()))
             return true;
     }
     return false;
 }

 // Get a token from an image argument to use as an error message token.
 const char *GetImageArgumentToken(TIntermTyped *imageNode)
 {
     ASSERT(IsImage(imageNode->getBasicType()));
     while (imageNode->getAsBinaryNode() &&
            (imageNode->getAsBinaryNode()->getOp() == EOpIndexIndirect ||
             imageNode->getAsBinaryNode()->getOp() == EOpIndexDirect))
     {
         imageNode = imageNode->getAsBinaryNode()->getLeft();
     }
     TIntermSymbol *imageSymbol = imageNode->getAsSymbolNode();
     if (imageSymbol)
     {
         return imageSymbol->getSymbol().c_str();
     }
     return "image";
 }

 bool CanSetDefaultPrecisionOnType(const TPublicType &type)
 {
     if (!SupportsPrecision(type.getBasicType()))
     {
         return false;
     }
     if (type.getBasicType() == EbtUInt)
     {
         // ESSL 3.00.4 section 4.5.4
         return false;
     }
     if (type.isAggregate())
     {
         // Not allowed to set for aggregate types
         return false;
     }
     return true;
 }

 // Map input primitive types to input array sizes in a geometry shader.
 GLuint GetGeometryShaderInputArraySize(TLayoutPrimitiveType primitiveType)
 {
     switch (primitiveType)
     {
         case EptPoints:
             return 1u;
         case EptLines:
             return 2u;
         case EptTriangles:
             return 3u;
         case EptLinesAdjacency:
             return 4u;
         case EptTrianglesAdjacency:
             return 6u;
         default:
             UNREACHABLE();
             return 0u;
     }
 }

 }  // namespace

 // This tracks each binding point's current default offset for inheritance of subsequent
 // variables using the same binding, and keeps offsets unique and non overlapping.
 // See GLSL ES 3.1, section 4.4.6.
 class TParseContext::AtomicCounterBindingState
 {
   public:
     AtomicCounterBindingState() : mDefaultOffset(0) {}
     // Inserts a new span and returns -1 if overlapping, else returns the starting offset of
     // newly inserted span.
     int insertSpan(int start, size_t length)
     {
         gl::RangeI newSpan(start, start + static_cast<int>(length));
         for (const auto &span : mSpans)
         {
             if (newSpan.intersects(span))
             {
                 return -1;
             }
         }
         mSpans.push_back(newSpan);
         mDefaultOffset = newSpan.high();
         return start;
     }
     // Inserts a new span starting from the default offset.
     int appendSpan(size_t length) { return insertSpan(mDefaultOffset, length); }
     void setDefaultOffset(int offset) { mDefaultOffset = offset; }

   private:
     int mDefaultOffset;
     std::vector<gl::RangeI> mSpans;
 };

 TParseContext::TParseContext(TSymbolTable &symt,
                              TExtensionBehavior &ext,
                              sh::GLenum type,
                              ShShaderSpec spec,
                              ShCompileOptions options,
                              bool checksPrecErrors,
                              TDiagnostics *diagnostics,
                              const ShBuiltInResources &resources)
     : symbolTable(symt),
       mDeferredNonEmptyDeclarationErrorCheck(false),
       mShaderType(type),
       mShaderSpec(spec),
       mCompileOptions(options),
       mShaderVersion(100),
       mTreeRoot(nullptr),
       mLoopNestingLevel(0),
       mStructNestingLevel(0),
       mSwitchNestingLevel(0),
       mCurrentFunctionType(nullptr),
       mFunctionReturnsValue(false),
       mChecksPrecisionErrors(checksPrecErrors),
       mFragmentPrecisionHighOnESSL1(false),
       mDefaultUniformMatrixPacking(EmpColumnMajor),
       mDefaultUniformBlockStorage(sh::IsWebGLBasedSpec(spec) ? EbsStd140 : EbsShared),
       mDefaultBufferMatrixPacking(EmpColumnMajor),
       mDefaultBufferBlockStorage(sh::IsWebGLBasedSpec(spec) ? EbsStd140 : EbsShared),
       mDiagnostics(diagnostics),
       mDirectiveHandler(ext,
                         *mDiagnostics,
                         mShaderVersion,
                         mShaderType,
                         resources.WEBGL_debug_shader_precision == 1),
       mPreprocessor(mDiagnostics, &mDirectiveHandler, pp::PreprocessorSettings()),
       mScanner(nullptr),
       mUsesFragData(false),
       mUsesFragColor(false),
       mUsesSecondaryOutputs(false),
       mMinProgramTexelOffset(resources.MinProgramTexelOffset),
       mMaxProgramTexelOffset(resources.MaxProgramTexelOffset),
       mMinProgramTextureGatherOffset(resources.MinProgramTextureGatherOffset),
       mMaxProgramTextureGatherOffset(resources.MaxProgramTextureGatherOffset),
       mComputeShaderLocalSizeDeclared(false),
       mNumViews(-1),
       mMaxNumViews(resources.MaxViewsOVR),
       mMaxImageUnits(resources.MaxImageUnits),
       mMaxCombinedTextureImageUnits(resources.MaxCombinedTextureImageUnits),
       mMaxUniformLocations(resources.MaxUniformLocations),
       mMaxUniformBufferBindings(resources.MaxUniformBufferBindings),
       mMaxAtomicCounterBindings(resources.MaxAtomicCounterBindings),
       mMaxShaderStorageBufferBindings(resources.MaxShaderStorageBufferBindings),
       mDeclaringFunction(false),
       mGeometryShaderInputPrimitiveType(EptUndefined),
       mGeometryShaderOutputPrimitiveType(EptUndefined),
       mGeometryShaderInvocations(0),
       mGeometryShaderMaxVertices(-1),
       mMaxGeometryShaderInvocations(resources.MaxGeometryShaderInvocations),
       mMaxGeometryShaderMaxVertices(resources.MaxGeometryOutputVertices),
       mGeometryShaderInputArraySize(0u)
 {
     mComputeShaderLocalSize.fill(-1);
 }

 TParseContext::~TParseContext()
 {
 }

 bool TParseContext::parseVectorFields(const TSourceLoc &line,
                                       const TString &compString,
                                       int vecSize,
                                       TVector<int> *fieldOffsets)
 {
     ASSERT(fieldOffsets);
     size_t fieldCount = compString.size();
     if (fieldCount > 4u)
     {
         error(line, "illegal vector field selection", compString.c_str());
         return false;
     }
     fieldOffsets->resize(fieldCount);

     enum
     {
         exyzw,
         ergba,
         estpq
     } fieldSet[4];

     for (unsigned int i = 0u; i < fieldOffsets->size(); ++i)
     {
         switch (compString[i])
         {
             case 'x':
                 (*fieldOffsets)[i] = 0;
                 fieldSet[i]       = exyzw;
                 break;
             case 'r':
                 (*fieldOffsets)[i] = 0;
                 fieldSet[i]       = ergba;
                 break;
             case 's':
                 (*fieldOffsets)[i] = 0;
                 fieldSet[i]       = estpq;
                 break;
             case 'y':
                 (*fieldOffsets)[i] = 1;
                 fieldSet[i]       = exyzw;
                 break;
             case 'g':
                 (*fieldOffsets)[i] = 1;
                 fieldSet[i]       = ergba;
                 break;
             case 't':
                 (*fieldOffsets)[i] = 1;
                 fieldSet[i]       = estpq;
                 break;
             case 'z':
                 (*fieldOffsets)[i] = 2;
                 fieldSet[i]       = exyzw;
                 break;
             case 'b':
                 (*fieldOffsets)[i] = 2;
                 fieldSet[i]       = ergba;
                 break;
             case 'p':
                 (*fieldOffsets)[i] = 2;
                 fieldSet[i]       = estpq;
                 break;

             case 'w':
                 (*fieldOffsets)[i] = 3;
                 fieldSet[i]       = exyzw;
                 break;
             case 'a':
                 (*fieldOffsets)[i] = 3;
                 fieldSet[i]       = ergba;
                 break;
             case 'q':
                 (*fieldOffsets)[i] = 3;
                 fieldSet[i]       = estpq;
                 break;
             default:
                 error(line, "illegal vector field selection", compString.c_str());
                 return false;
         }
     }

     for (unsigned int i = 0u; i < fieldOffsets->size(); ++i)
     {
         if ((*fieldOffsets)[i] >= vecSize)
         {
             error(line, "vector field selection out of range", compString.c_str());
             return false;
         }

         if (i > 0)
         {
             if (fieldSet[i] != fieldSet[i - 1])
             {
                 error(line, "illegal - vector component fields not from the same set",
                       compString.c_str());
                 return false;
             }
         }
     }

     return true;
 }

 ///////////////////////////////////////////////////////////////////////
 //
 // Errors
 //
 ////////////////////////////////////////////////////////////////////////

 //
 // Used by flex/bison to output all syntax and parsing errors.
 //
 void TParseContext::error(const TSourceLoc &loc, const char *reason, const char *token)
 {
     mDiagnostics->error(loc, reason, token);
 }

 void TParseContext::warning(const TSourceLoc &loc, const char *reason, const char *token)
 {
     mDiagnostics->warning(loc, reason, token);
 }

 void TParseContext::outOfRangeError(bool isError,
                                     const TSourceLoc &loc,
                                     const char *reason,
                                     const char *token)
 {
     if (isError)
     {
         error(loc, reason, token);
     }
     else
     {
         warning(loc, reason, token);
     }
 }

 //
 // Same error message for all places assignments don't work.
 //
 void TParseContext::assignError(const TSourceLoc &line, const char *op, TString left, TString right)
 {
     std::stringstream reasonStream;
     reasonStream << "cannot convert from '" << right << "' to '" << left << "'";
     std::string reason = reasonStream.str();
     error(line, reason.c_str(), op);
 }

 //
 // Same error message for all places unary operations don't work.
 //
 void TParseContext::unaryOpError(const TSourceLoc &line, const char *op, TString operand)
 {
     std::stringstream reasonStream;
     reasonStream << "wrong operand type - no operation '" << op
                  << "' exists that takes an operand of type " << operand
                  << " (or there is no acceptable conversion)";
     std::string reason = reasonStream.str();
     error(line, reason.c_str(), op);
 }

 //
 // Same error message for all binary operations don't work.
 //
 void TParseContext::binaryOpError(const TSourceLoc &line,
                                   const char *op,
                                   TString left,
                                   TString right)
 {
     std::stringstream reasonStream;
     reasonStream << "wrong operand types - no operation '" << op
                  << "' exists that takes a left-hand operand of type '" << left
                  << "' and a right operand of type '" << right
                  << "' (or there is no acceptable conversion)";
     std::string reason = reasonStream.str();
     error(line, reason.c_str(), op);
 }

 void TParseContext::checkPrecisionSpecified(const TSourceLoc &line,
                                             TPrecision precision,
                                             TBasicType type)
 {
     if (!mChecksPrecisionErrors)
         return;

     if (precision != EbpUndefined && !SupportsPrecision(type))
     {
         error(line, "illegal type for precision qualifier", getBasicString(type));
     }

     if (precision == EbpUndefined)
     {
         switch (type)
         {
             case EbtFloat:
                 error(line, "No precision specified for (float)", "");
                 return;
             case EbtInt:
             case EbtUInt:
                 UNREACHABLE();  // there's always a predeclared qualifier
                 error(line, "No precision specified (int)", "");
                 return;
             default:
                 if (IsOpaqueType(type))
                 {
                     error(line, "No precision specified", getBasicString(type));
                     return;
                 }
         }
     }
 }

 // Both test and if necessary, spit out an error, to see if the node is really
 // an l-value that can be operated on this way.
 bool TParseContext::checkCanBeLValue(const TSourceLoc &line, const char *op, TIntermTyped *node)
 {
     TIntermSymbol *symNode      = node->getAsSymbolNode();
     TIntermBinary *binaryNode   = node->getAsBinaryNode();
     TIntermSwizzle *swizzleNode = node->getAsSwizzleNode();

     if (swizzleNode)
     {
         bool ok = checkCanBeLValue(line, op, swizzleNode->getOperand());
         if (ok && swizzleNode->hasDuplicateOffsets())
         {
             error(line, " l-value of swizzle cannot have duplicate components", op);
             return false;
         }
         return ok;
     }

     if (binaryNode)
     {
         switch (binaryNode->getOp())
         {
             case EOpIndexDirect:
             case EOpIndexIndirect:
             case EOpIndexDirectStruct:
             case EOpIndexDirectInterfaceBlock:
                 return checkCanBeLValue(line, op, binaryNode->getLeft());
             default:
                 break;
         }
         error(line, " l-value required", op);
         return false;
     }

     std::string message;
     switch (node->getQualifier())
     {
         case EvqConst:
             message = "can't modify a const";
             break;
         case EvqConstReadOnly:
             message = "can't modify a const";
             break;
         case EvqAttribute:
             message = "can't modify an attribute";
             break;
         case EvqFragmentIn:
         case EvqVertexIn:
         case EvqGeometryIn:
         case EvqFlatIn:
         case EvqSmoothIn:
         case EvqCentroidIn:
             message = "can't modify an input";
             break;
         case EvqUniform:
             message = "can't modify a uniform";
             break;
         case EvqVaryingIn:
             message = "can't modify a varying";
             break;
         case EvqFragCoord:
             message = "can't modify gl_FragCoord";
             break;
         case EvqFrontFacing:
             message = "can't modify gl_FrontFacing";
             break;
         case EvqPointCoord:
             message = "can't modify gl_PointCoord";
             break;
         case EvqNumWorkGroups:
             message = "can't modify gl_NumWorkGroups";
             break;
         case EvqWorkGroupSize:
             message = "can't modify gl_WorkGroupSize";
             break;
         case EvqWorkGroupID:
             message = "can't modify gl_WorkGroupID";
             break;
         case EvqLocalInvocationID:
             message = "can't modify gl_LocalInvocationID";
             break;
         case EvqGlobalInvocationID:
             message = "can't modify gl_GlobalInvocationID";
             break;
         case EvqLocalInvocationIndex:
             message = "can't modify gl_LocalInvocationIndex";
             break;
         case EvqViewIDOVR:
             message = "can't modify gl_ViewID_OVR";
             break;
         case EvqComputeIn:
             message = "can't modify work group size variable";
             break;
         case EvqPerVertexIn:
             message = "can't modify any member in gl_in";
             break;
         case EvqPrimitiveIDIn:
             message = "can't modify gl_PrimitiveIDIn";
             break;
         case EvqInvocationID:
             message = "can't modify gl_InvocationID";
             break;
         case EvqPrimitiveID:
             if (mShaderType == GL_FRAGMENT_SHADER)
             {
                 message = "can't modify gl_PrimitiveID in a fragment shader";
             }
             break;
         case EvqLayer:
             if (mShaderType == GL_FRAGMENT_SHADER)
             {
                 message = "can't modify gl_Layer in a fragment shader";
             }
             break;
         default:
             //
             // Type that can't be written to?
             //
             if (node->getBasicType() == EbtVoid)
             {
                 message = "can't modify void";
             }
             if (IsOpaqueType(node->getBasicType()))
             {
                 message = "can't modify a variable with type ";
                 message += getBasicString(node->getBasicType());
             }
             else if (node->getMemoryQualifier().readonly)
             {
                 message = "can't modify a readonly variable";
             }
     }

     if (message.empty() && binaryNode == 0 && symNode == 0)
     {
         error(line, "l-value required", op);

         return false;
     }

     //
     // Everything else is okay, no error.
     //
     if (message.empty())
         return true;

     //
     // If we get here, we have an error and a message.
     //
     if (symNode)
     {
         const char *symbol = symNode->getSymbol().c_str();
         std::stringstream reasonStream;
         reasonStream << "l-value required (" << message << " \"" << symbol << "\")";
         std::string reason = reasonStream.str();
         error(line, reason.c_str(), op);
     }
     else
     {
         std::stringstream reasonStream;
         reasonStream << "l-value required (" << message << ")";
         std::string reason = reasonStream.str();
         error(line, reason.c_str(), op);
     }

     return false;
 }

 // Both test, and if necessary spit out an error, to see if the node is really
 // a constant.
 void TParseContext::checkIsConst(TIntermTyped *node)
 {
     if (node->getQualifier() != EvqConst)
     {
         error(node->getLine(), "constant expression required", "");
     }
 }

 // Both test, and if necessary spit out an error, to see if the node is really
 // an integer.
 void TParseContext::checkIsScalarInteger(TIntermTyped *node, const char *token)
 {
     if (!node->isScalarInt())
     {
         error(node->getLine(), "integer expression required", token);
     }
 }

 // Both test, and if necessary spit out an error, to see if we are currently
 // globally scoped.
 bool TParseContext::checkIsAtGlobalLevel(const TSourceLoc &line, const char *token)
 {
     if (!symbolTable.atGlobalLevel())
     {
         error(line, "only allowed at global scope", token);
         return false;
     }
     return true;
 }

 // ESSL 3.00.5 sections 3.8 and 3.9.
 // If it starts "gl_" or contains two consecutive underscores, it's reserved.
 // Also checks for "webgl_" and "_webgl_" reserved identifiers if parsing a webgl shader.
 bool TParseContext::checkIsNotReserved(const TSourceLoc &line, const TString &identifier)
 {
     static const char *reservedErrMsg = "reserved built-in name";
     if (identifier.compare(0, 3, "gl_") == 0)
     {
         error(line, reservedErrMsg, "gl_");
         return false;
     }
     if (sh::IsWebGLBasedSpec(mShaderSpec))
     {
         if (identifier.compare(0, 6, "webgl_") == 0)
         {
             error(line, reservedErrMsg, "webgl_");
             return false;
         }
         if (identifier.compare(0, 7, "_webgl_") == 0)
         {
             error(line, reservedErrMsg, "_webgl_");
             return false;
         }
     }
     if (identifier.find("__") != TString::npos)
     {
         error(line,
               "identifiers containing two consecutive underscores (__) are reserved as "
               "possible future keywords",
               identifier.c_str());
         return false;
     }
     return true;
 }

 // Make sure the argument types are correct for constructing a specific type.
 bool TParseContext::checkConstructorArguments(const TSourceLoc &line,
                                               const TIntermSequence *arguments,
                                               const TType &type)
 {
     if (arguments->empty())
     {
         error(line, "constructor does not have any arguments", "constructor");
         return false;
     }

     for (TIntermNode *arg : *arguments)
     {
         const TIntermTyped *argTyped = arg->getAsTyped();
         ASSERT(argTyped != nullptr);
         if (type.getBasicType() != EbtStruct && IsOpaqueType(argTyped->getBasicType()))
         {
             std::string reason("cannot convert a variable with type ");
             reason += getBasicString(argTyped->getBasicType());
             error(line, reason.c_str(), "constructor");
             return false;
         }
         else if (argTyped->getMemoryQualifier().writeonly)
         {
             error(line, "cannot convert a variable with writeonly", "constructor");
             return false;
         }
         if (argTyped->getBasicType() == EbtVoid)
         {
             error(line, "cannot convert a void", "constructor");
             return false;
         }
     }

     if (type.isArray())
     {
         // The size of an unsized constructor should already have been determined.
         ASSERT(!type.isUnsizedArray());
         if (static_cast<size_t>(type.getOutermostArraySize()) != arguments->size())
         {
             error(line, "array constructor needs one argument per array element", "constructor");
             return false;
         }
         // GLSL ES 3.00 section 5.4.4: Each argument must be the same type as the element type of
         // the array.
         for (TIntermNode *const &argNode : *arguments)
         {
             const TType &argType = argNode->getAsTyped()->getType();
             if (argType.isArray())
             {
                 error(line, "constructing from a non-dereferenced array", "constructor");
                 return false;
             }
             if (!argType.isElementTypeOf(type))
             {
                 error(line, "Array constructor argument has an incorrect type", "constructor");
                 return false;
             }
         }
     }
     else if (type.getBasicType() == EbtStruct)
     {
         const TFieldList &fields = type.getStruct()->fields();
         if (fields.size() != arguments->size())
         {
             error(line,
                   "Number of constructor parameters does not match the number of structure fields",
                   "constructor");
             return false;
         }

         for (size_t i = 0; i < fields.size(); i++)
         {
             if (i >= arguments->size() ||
                 (*arguments)[i]->getAsTyped()->getType() != *fields[i]->type())
             {
                 error(line, "Structure constructor arguments do not match structure fields",
                       "constructor");
                 return false;
             }
         }
     }
     else
     {
         // We're constructing a scalar, vector, or matrix.

         // Note: It's okay to have too many components available, but not okay to have unused
         // arguments. 'full' will go to true when enough args have been seen. If we loop again,
         // there is an extra argument, so 'overFull' will become true.

         size_t size    = 0;
         bool full      = false;
         bool overFull  = false;
         bool matrixArg = false;
         for (TIntermNode *arg : *arguments)
         {
             const TIntermTyped *argTyped = arg->getAsTyped();
             ASSERT(argTyped != nullptr);

             if (argTyped->getBasicType() == EbtStruct)
             {
                 error(line, "a struct cannot be used as a constructor argument for this type",
                       "constructor");
                 return false;
             }
             if (argTyped->getType().isArray())
             {
                 error(line, "constructing from a non-dereferenced array", "constructor");
                 return false;
             }
             if (argTyped->getType().isMatrix())
             {
                 matrixArg = true;
             }

             size += argTyped->getType().getObjectSize();
             if (full)
             {
                 overFull = true;
             }
             if (size >= type.getObjectSize())
             {
                 full = true;
             }
         }

         if (type.isMatrix() && matrixArg)
         {
             if (arguments->size() != 1)
             {
                 error(line, "constructing matrix from matrix can only take one argument",
                       "constructor");
                 return false;
             }
         }
         else
         {
             if (size != 1 && size < type.getObjectSize())
             {
                 error(line, "not enough data provided for construction", "constructor");
                 return false;
             }
             if (overFull)
             {
                 error(line, "too many arguments", "constructor");
                 return false;
             }
         }
     }

     return true;
 }

 // This function checks to see if a void variable has been declared and raise an error message for
 // such a case
 //
 // returns true in case of an error
 //
 bool TParseContext::checkIsNonVoid(const TSourceLoc &line,
                                    const TString &identifier,
                                    const TBasicType &type)
 {
     if (type == EbtVoid)
     {
         error(line, "illegal use of type 'void'", identifier.c_str());
         return false;
     }

     return true;
 }

 // This function checks to see if the node (for the expression) contains a scalar boolean expression
 // or not.
 bool TParseContext::checkIsScalarBool(const TSourceLoc &line, const TIntermTyped *type)
 {
     if (type->getBasicType() != EbtBool || !type->isScalar())
     {
         error(line, "boolean expression expected", "");
         return false;
     }
     return true;
 }

 // This function checks to see if the node (for the expression) contains a scalar boolean expression
 // or not.
 void TParseContext::checkIsScalarBool(const TSourceLoc &line, const TPublicType &pType)
 {
     if (pType.getBasicType() != EbtBool || pType.isAggregate())
     {
         error(line, "boolean expression expected", "");
     }
 }

 bool TParseContext::checkIsNotOpaqueType(const TSourceLoc &line,
                                          const TTypeSpecifierNonArray &pType,
                                          const char *reason)
 {
     if (pType.type == EbtStruct)
     {
         if (ContainsSampler(pType.userDef))
         {
             std::stringstream reasonStream;
             reasonStream << reason << " (structure contains a sampler)";
             std::string reasonStr = reasonStream.str();
             error(line, reasonStr.c_str(), getBasicString(pType.type));
             return false;
         }
         // only samplers need to be checked from structs, since other opaque types can't be struct
         // members.
         return true;
     }
     else if (IsOpaqueType(pType.type))
     {
         error(line, reason, getBasicString(pType.type));
         return false;
     }

     return true;
 }

 void TParseContext::checkDeclaratorLocationIsNotSpecified(const TSourceLoc &line,
                                                           const TPublicType &pType)
 {
     if (pType.layoutQualifier.location != -1)
     {
         error(line, "location must only be specified for a single input or output variable",
               "location");
     }
 }

 void TParseContext::checkLocationIsNotSpecified(const TSourceLoc &location,
                                                 const TLayoutQualifier &layoutQualifier)
 {
     if (layoutQualifier.location != -1)
     {
         const char *errorMsg = "invalid layout qualifier: only valid on program inputs and outputs";
         if (mShaderVersion >= 310)
         {
             errorMsg =
                 "invalid layout qualifier: only valid on shader inputs, outputs, and uniforms";
         }
         error(location, errorMsg, "location");
     }
 }

 void TParseContext::checkStd430IsForShaderStorageBlock(const TSourceLoc &location,
                                                        const TLayoutBlockStorage &blockStorage,
                                                        const TQualifier &qualifier)
 {
     if (blockStorage == EbsStd430 && qualifier != EvqBuffer)
     {
         error(location, "The std430 layout is supported only for shader storage blocks.", "std430");
     }
 }

 void TParseContext::checkOutParameterIsNotOpaqueType(const TSourceLoc &line,
                                                      TQualifier qualifier,
                                                      const TType &type)
 {
     ASSERT(qualifier == EvqOut || qualifier == EvqInOut);
     if (IsOpaqueType(type.getBasicType()))
     {
         error(line, "opaque types cannot be output parameters", type.getBasicString());
     }
 }

 // Do size checking for an array type's size.
 unsigned int TParseContext::checkIsValidArraySize(const TSourceLoc &line, TIntermTyped *expr)
 {
     TIntermConstantUnion *constant = expr->getAsConstantUnion();

     // TODO(oetuaho@nvidia.com): Get rid of the constant == nullptr check here once all constant
     // expressions can be folded. Right now we don't allow constant expressions that ANGLE can't
     // fold as array size.
     if (expr->getQualifier() != EvqConst || constant == nullptr || !constant->isScalarInt())
     {
         error(line, "array size must be a constant integer expression", "");
         return 1u;
     }

     unsigned int size = 0u;

     if (constant->getBasicType() == EbtUInt)
     {
         size = constant->getUConst(0);
     }
     else
     {
         int signedSize = constant->getIConst(0);

         if (signedSize < 0)
         {
             error(line, "array size must be non-negative", "");
             return 1u;
         }

         size = static_cast<unsigned int>(signedSize);
     }

     if (size == 0u)
     {
         error(line, "array size must be greater than zero", "");
         return 1u;
     }

     // The size of arrays is restricted here to prevent issues further down the
     // compiler/translator/driver stack. Shader Model 5 generation hardware is limited to
     // 4096 registers so this should be reasonable even for aggressively optimizable code.
     const unsigned int sizeLimit = 65536;

     if (size > sizeLimit)
     {
         error(line, "array size too large", "");
         return 1u;
     }

     return size;
 }

 // See if this qualifier can be an array.
 bool TParseContext::checkIsValidQualifierForArray(const TSourceLoc &line,
                                                   const TPublicType &elementQualifier)
 {
     if ((elementQualifier.qualifier == EvqAttribute) ||
         (elementQualifier.qualifier == EvqVertexIn) ||
         (elementQualifier.qualifier == EvqConst && mShaderVersion < 300))
     {
         error(line, "cannot declare arrays of this qualifier",
               TType(elementQualifier).getQualifierString());
         return false;
     }

     return true;
 }

 // See if this element type can be formed into an array.
 bool TParseContext::checkArrayElementIsNotArray(const TSourceLoc &line,
                                                 const TPublicType &elementType)
 {
     if (elementType.array)
     {
         error(line, "cannot declare arrays of arrays",
               TType(elementType).getCompleteString().c_str());
         return false;
     }
     return true;
 }

 // Check if this qualified element type can be formed into an array. This is only called when array
 // brackets are associated with an identifier in a declaration, like this:
 //   float a[2];
 // Similar checks are done in addFullySpecifiedType for array declarations where the array brackets
 // are associated with the type, like this:
 //   float[2] a;
 bool TParseContext::checkIsValidTypeAndQualifierForArray(const TSourceLoc &indexLocation,
                                                          const TPublicType &elementType)
 {
     if (!checkArrayElementIsNotArray(indexLocation, elementType))
     {
         return false;
     }
     // In ESSL1.00 shaders, structs cannot be varying (section 4.3.5). This is checked elsewhere.
     // In ESSL3.00 shaders, struct inputs/outputs are allowed but not arrays of structs (section
     // 4.3.4).
     if (mShaderVersion >= 300 && elementType.getBasicType() == EbtStruct &&
         sh::IsVarying(elementType.qualifier))
     {
         error(indexLocation, "cannot declare arrays of structs of this qualifier",
               TType(elementType).getCompleteString().c_str());
         return false;
     }
     return checkIsValidQualifierForArray(indexLocation, elementType);
 }

 // Enforce non-initializer type/qualifier rules.
 void TParseContext::checkCanBeDeclaredWithoutInitializer(const TSourceLoc &line,
                                                          const TString &identifier,
                                                          TType *type)
 {
     ASSERT(type != nullptr);
     if (type->getQualifier() == EvqConst)
     {
         // Make the qualifier make sense.
         type->setQualifier(EvqTemporary);

         // Generate informative error messages for ESSL1.
         // In ESSL3 arrays and structures containing arrays can be constant.
         if (mShaderVersion < 300 && type->isStructureContainingArrays())
         {
             error(line,
                   "structures containing arrays may not be declared constant since they cannot be "
                   "initialized",
                   identifier.c_str());
         }
         else
         {
             error(line, "variables with qualifier 'const' must be initialized", identifier.c_str());
         }
     }
     // This will make the type sized if it isn't sized yet.
     checkIsNotUnsizedArray(line, "implicitly sized arrays need to be initialized",
                            identifier.c_str(), type);
 }

 // Do some simple checks that are shared between all variable declarations,
 // and update the symbol table.
 //
 // Returns true if declaring the variable succeeded.
 //
 bool TParseContext::declareVariable(const TSourceLoc &line,
                                     const TString &identifier,
                                     const TType &type,
                                     TVariable **variable)
 {
     ASSERT((*variable) == nullptr);

     checkBindingIsValid(line, type);

     bool needsReservedCheck = true;

     // gl_LastFragData may be redeclared with a new precision qualifier
     if (type.isArray() && identifier.compare(0, 15, "gl_LastFragData") == 0)
     {
         const TVariable *maxDrawBuffers = static_cast<const TVariable *>(
             symbolTable.findBuiltIn("gl_MaxDrawBuffers", mShaderVersion));
         if (type.isArrayOfArrays())
         {
             error(line, "redeclaration of gl_LastFragData as an array of arrays",
                   identifier.c_str());
             return false;
         }
         else if (static_cast<int>(type.getOutermostArraySize()) ==
                  maxDrawBuffers->getConstPointer()->getIConst())
         {
             if (TSymbol *builtInSymbol = symbolTable.findBuiltIn(identifier, mShaderVersion))
             {
                 needsReservedCheck = !checkCanUseExtension(line, builtInSymbol->getExtension());
             }
         }
         else
         {
             error(line, "redeclaration of gl_LastFragData with size != gl_MaxDrawBuffers",
                   identifier.c_str());
             return false;
         }
     }

     if (needsReservedCheck && !checkIsNotReserved(line, identifier))
         return false;

     (*variable) = symbolTable.declareVariable(&identifier, type);
     if (!(*variable))
     {
         error(line, "redefinition", identifier.c_str());
         return false;
     }

     if (!checkIsNonVoid(line, identifier, type.getBasicType()))
         return false;

     return true;
 }

 void TParseContext::checkIsParameterQualifierValid(
     const TSourceLoc &line,
     const TTypeQualifierBuilder &typeQualifierBuilder,
     TType *type)
 {
     // The only parameter qualifiers a parameter can have are in, out, inout or const.
     TTypeQualifier typeQualifier = typeQualifierBuilder.getParameterTypeQualifier(mDiagnostics);

     if (typeQualifier.qualifier == EvqOut || typeQualifier.qualifier == EvqInOut)
     {
         checkOutParameterIsNotOpaqueType(line, typeQualifier.qualifier, *type);
     }

     if (!IsImage(type->getBasicType()))
     {
         checkMemoryQualifierIsNotSpecified(typeQualifier.memoryQualifier, line);
     }
     else
     {
         type->setMemoryQualifier(typeQualifier.memoryQualifier);
     }

     type->setQualifier(typeQualifier.qualifier);

     if (typeQualifier.precision != EbpUndefined)
     {
         type->setPrecision(typeQualifier.precision);
     }
 }

 bool TParseContext::checkCanUseExtension(const TSourceLoc &line, TExtension extension)
 {
     ASSERT(extension != TExtension::UNDEFINED);
     const TExtensionBehavior &extBehavior   = extensionBehavior();
     TExtensionBehavior::const_iterator iter = extBehavior.find(extension);
     if (iter == extBehavior.end())
     {
         error(line, "extension is not supported", GetExtensionNameString(extension));
         return false;
     }
     // In GLSL ES, an extension's default behavior is "disable".
     if (iter->second == EBhDisable || iter->second == EBhUndefined)
     {
         error(line, "extension is disabled", GetExtensionNameString(extension));
         return false;
     }
     if (iter->second == EBhWarn)
     {
         warning(line, "extension is being used", GetExtensionNameString(extension));
         return true;
     }

     return true;
 }

 // ESSL 3.00.6 section 4.8 Empty Declarations: "The combinations of qualifiers that cause
 // compile-time or link-time errors are the same whether or not the declaration is empty".
 // This function implements all the checks that are done on qualifiers regardless of if the
 // declaration is empty.
 void TParseContext::declarationQualifierErrorCheck(const sh::TQualifier qualifier,
                                                    const sh::TLayoutQualifier &layoutQualifier,
                                                    const TSourceLoc &location)
 {
     if (qualifier == EvqShared && !layoutQualifier.isEmpty())
     {
         error(location, "Shared memory declarations cannot have layout specified", "layout");
     }

     if (layoutQualifier.matrixPacking != EmpUnspecified)
     {
         error(location, "layout qualifier only valid for interface blocks",
               getMatrixPackingString(layoutQualifier.matrixPacking));
         return;
     }

     if (layoutQualifier.blockStorage != EbsUnspecified)
     {
         error(location, "layout qualifier only valid for interface blocks",
               getBlockStorageString(layoutQualifier.blockStorage));
         return;
     }

     if (qualifier == EvqFragmentOut)
     {
         if (layoutQualifier.location != -1 && layoutQualifier.yuv == true)
         {
             error(location, "invalid layout qualifier combination", "yuv");
             return;
         }
     }
     else
     {
         checkYuvIsNotSpecified(location, layoutQualifier.yuv);
     }

     // If multiview extension is enabled, "in" qualifier is allowed in the vertex shader in previous
     // parsing steps. So it needs to be checked here.
     if (isExtensionEnabled(TExtension::OVR_multiview) && mShaderVersion < 300 &&
         qualifier == EvqVertexIn)
     {
         error(location, "storage qualifier supported in GLSL ES 3.00 and above only", "in");
     }

     bool canHaveLocation = qualifier == EvqVertexIn || qualifier == EvqFragmentOut;
     if (mShaderVersion >= 310)
     {
         canHaveLocation = canHaveLocation || qualifier == EvqUniform || IsVarying(qualifier);
         // We're not checking whether the uniform location is in range here since that depends on
         // the type of the variable.
         // The type can only be fully determined for non-empty declarations.
     }
     if (!canHaveLocation)
     {
         checkLocationIsNotSpecified(location, layoutQualifier);
     }
 }

 void TParseContext::atomicCounterQualifierErrorCheck(const TPublicType &publicType,
                                                      const TSourceLoc &location)
 {
     if (publicType.precision != EbpHigh)
     {
         error(location, "Can only be highp", "atomic counter");
     }
     // dEQP enforces compile error if location is specified. See uniform_location.test.
     if (publicType.layoutQualifier.location != -1)
     {
         error(location, "location must not be set for atomic_uint", "layout");
     }
     if (publicType.layoutQualifier.binding == -1)
     {
         error(location, "no binding specified", "atomic counter");
     }
 }

 void TParseContext::emptyDeclarationErrorCheck(const TType &type, const TSourceLoc &location)
 {
     if (type.isUnsizedArray())
     {
         // ESSL3 spec section 4.1.9: Array declaration which leaves the size unspecified is an
         // error. It is assumed that this applies to empty declarations as well.
         error(location, "empty array declaration needs to specify a size", "");
     }
 }

 // These checks are done for all declarations that are non-empty. They're done for non-empty
 // declarations starting a declarator list, and declarators that follow an empty declaration.
 void TParseContext::nonEmptyDeclarationErrorCheck(const TPublicType &publicType,
                                                   const TSourceLoc &identifierLocation)
 {
     switch (publicType.qualifier)
     {
         case EvqVaryingIn:
         case EvqVaryingOut:
         case EvqAttribute:
         case EvqVertexIn:
         case EvqFragmentOut:
         case EvqComputeIn:
             if (publicType.getBasicType() == EbtStruct)
             {
                 error(identifierLocation, "cannot be used with a structure",
                       getQualifierString(publicType.qualifier));
                 return;
             }
             break;
         case EvqBuffer:
             if (publicType.getBasicType() != EbtInterfaceBlock)
             {
                 error(identifierLocation,
                       "cannot declare buffer variables at global scope(outside a block)",
                       getQualifierString(publicType.qualifier));
                 return;
             }
             break;
         default:
             break;
     }
     std::string reason(getBasicString(publicType.getBasicType()));
     reason += "s must be uniform";
     if (publicType.qualifier != EvqUniform &&
         !checkIsNotOpaqueType(identifierLocation, publicType.typeSpecifierNonArray, reason.c_str()))
     {
         return;
     }

     if ((publicType.qualifier != EvqTemporary && publicType.qualifier != EvqGlobal &&
          publicType.qualifier != EvqConst) &&
         publicType.getBasicType() == EbtYuvCscStandardEXT)
     {
         error(identifierLocation, "cannot be used with a yuvCscStandardEXT",
               getQualifierString(publicType.qualifier));
         return;
     }

     if (mShaderVersion >= 310 && publicType.qualifier == EvqUniform)
     {
         // Valid uniform declarations can't be unsized arrays since uniforms can't be initialized.
         // But invalid shaders may still reach here with an unsized array declaration.
         TType type(publicType);
         if (!type.isUnsizedArray())
         {
             checkUniformLocationInRange(identifierLocation, type.getLocationCount(),
                                         publicType.layoutQualifier);
         }
     }

     // check for layout qualifier issues
     const TLayoutQualifier layoutQualifier = publicType.layoutQualifier;

     if (IsImage(publicType.getBasicType()))
     {

         switch (layoutQualifier.imageInternalFormat)
         {
             case EiifRGBA32F:
             case EiifRGBA16F:
             case EiifR32F:
             case EiifRGBA8:
             case EiifRGBA8_SNORM:
                 if (!IsFloatImage(publicType.getBasicType()))
                 {
                     error(identifierLocation,
                           "internal image format requires a floating image type",
                           getBasicString(publicType.getBasicType()));
                     return;
                 }
                 break;
             case EiifRGBA32I:
             case EiifRGBA16I:
             case EiifRGBA8I:
             case EiifR32I:
                 if (!IsIntegerImage(publicType.getBasicType()))
                 {
                     error(identifierLocation,
                           "internal image format requires an integer image type",
                           getBasicString(publicType.getBasicType()));
                     return;
                 }
                 break;
             case EiifRGBA32UI:
             case EiifRGBA16UI:
             case EiifRGBA8UI:
             case EiifR32UI:
                 if (!IsUnsignedImage(publicType.getBasicType()))
                 {
                     error(identifierLocation,
                           "internal image format requires an unsigned image type",
                           getBasicString(publicType.getBasicType()));
                     return;
                 }
                 break;
             case EiifUnspecified:
                 error(identifierLocation, "layout qualifier", "No image internal format specified");
                 return;
             default:
                 error(identifierLocation, "layout qualifier", "unrecognized token");
                 return;
         }

         // GLSL ES 3.10 Revision 4, 4.9 Memory Access Qualifiers
         switch (layoutQualifier.imageInternalFormat)
         {
             case EiifR32F:
             case EiifR32I:
             case EiifR32UI:
                 break;
             default:
                 if (!publicType.memoryQualifier.readonly && !publicType.memoryQualifier.writeonly)
                 {
                     error(identifierLocation, "layout qualifier",
                           "Except for images with the r32f, r32i and r32ui format qualifiers, "
                           "image variables must be qualified readonly and/or writeonly");
                     return;
                 }
                 break;
         }
     }
     else
     {
         checkInternalFormatIsNotSpecified(identifierLocation, layoutQualifier.imageInternalFormat);
         checkMemoryQualifierIsNotSpecified(publicType.memoryQualifier, identifierLocation);
     }

     if (IsAtomicCounter(publicType.getBasicType()))
     {
         atomicCounterQualifierErrorCheck(publicType, identifierLocation);
     }
     else
     {
         checkOffsetIsNotSpecified(identifierLocation, layoutQualifier.offset);
     }
 }

 void TParseContext::checkBindingIsValid(const TSourceLoc &identifierLocation, const TType &type)
 {
     TLayoutQualifier layoutQualifier = type.getLayoutQualifier();
     // Note that the ESSL 3.10 section 4.4.5 is not particularly clear on how the binding qualifier
     // on arrays of arrays should be handled. We interpret the spec so that the binding value is
     // incremented for each element of the innermost nested arrays. This is in line with how arrays
     // of arrays of blocks are specified to behave in GLSL 4.50 and a conservative interpretation
     // when it comes to which shaders are accepted by the compiler.
     int arrayTotalElementCount = type.getArraySizeProduct();
     if (IsImage(type.getBasicType()))
     {
         checkImageBindingIsValid(identifierLocation, layoutQualifier.binding,
                                  arrayTotalElementCount);
     }
     else if (IsSampler(type.getBasicType()))
     {
         checkSamplerBindingIsValid(identifierLocation, layoutQualifier.binding,
                                    arrayTotalElementCount);
     }
     else if (IsAtomicCounter(type.getBasicType()))
     {
         checkAtomicCounterBindingIsValid(identifierLocation, layoutQualifier.binding);
     }
     else
     {
         ASSERT(!IsOpaqueType(type.getBasicType()));
         checkBindingIsNotSpecified(identifierLocation, layoutQualifier.binding);
     }
 }

 void TParseContext::checkLayoutQualifierSupported(const TSourceLoc &location,
                                                   const TString &layoutQualifierName,
                                                   int versionRequired)
 {

     if (mShaderVersion < versionRequired)
     {
         error(location, "invalid layout qualifier: not supported", layoutQualifierName.c_str());
     }
 }

 bool TParseContext::checkWorkGroupSizeIsNotSpecified(const TSourceLoc &location,
                                                      const TLayoutQualifier &layoutQualifier)
 {
     const sh::WorkGroupSize &localSize = layoutQualifier.localSize;
     for (size_t i = 0u; i < localSize.size(); ++i)
     {
         if (localSize[i] != -1)
         {
             error(location,
                   "invalid layout qualifier: only valid when used with 'in' in a compute shader "
                   "global layout declaration",
                   getWorkGroupSizeString(i));
             return false;
         }
     }

     return true;
 }

 void TParseContext::checkInternalFormatIsNotSpecified(const TSourceLoc &location,
                                                       TLayoutImageInternalFormat internalFormat)
 {
     if (internalFormat != EiifUnspecified)
     {
         error(location, "invalid layout qualifier: only valid when used with images",
               getImageInternalFormatString(internalFormat));
     }
 }

 void TParseContext::checkBindingIsNotSpecified(const TSourceLoc &location, int binding)
 {
     if (binding != -1)
     {
         error(location,
               "invalid layout qualifier: only valid when used with opaque types or blocks",
               "binding");
     }
 }

 void TParseContext::checkOffsetIsNotSpecified(const TSourceLoc &location, int offset)
 {
     if (offset != -1)
     {
         error(location, "invalid layout qualifier: only valid when used with atomic counters",
               "offset");
     }
 }

 void TParseContext::checkImageBindingIsValid(const TSourceLoc &location,
                                              int binding,
                                              int arrayTotalElementCount)
 {
     // Expects arraySize to be 1 when setting binding for only a single variable.
     if (binding >= 0 && binding + arrayTotalElementCount > mMaxImageUnits)
     {
         error(location, "image binding greater than gl_MaxImageUnits", "binding");
     }
 }

 void TParseContext::checkSamplerBindingIsValid(const TSourceLoc &location,
                                                int binding,
                                                int arrayTotalElementCount)
 {
     // Expects arraySize to be 1 when setting binding for only a single variable.
     if (binding >= 0 && binding + arrayTotalElementCount > mMaxCombinedTextureImageUnits)
     {
         error(location, "sampler binding greater than maximum texture units", "binding");
     }
 }

 void TParseContext::checkBlockBindingIsValid(const TSourceLoc &location,
                                              const TQualifier &qualifier,
                                              int binding,
                                              int arraySize)
 {
     int size = (arraySize == 0 ? 1 : arraySize);
     if (qualifier == EvqUniform)
     {
         if (binding + size > mMaxUniformBufferBindings)
         {
             error(location, "uniform block binding greater than MAX_UNIFORM_BUFFER_BINDINGS",
                   "binding");
         }
     }
     else if (qualifier == EvqBuffer)
     {
         if (binding + size > mMaxShaderStorageBufferBindings)
         {
             error(location,
                   "shader storage block binding greater than MAX_SHADER_STORAGE_BUFFER_BINDINGS",
                   "binding");
         }
     }
 }
 void TParseContext::checkAtomicCounterBindingIsValid(const TSourceLoc &location, int binding)
 {
     if (binding >= mMaxAtomicCounterBindings)
     {
         error(location, "atomic counter binding greater than gl_MaxAtomicCounterBindings",
               "binding");
     }
 }

 void TParseContext::checkUniformLocationInRange(const TSourceLoc &location,
                                                 int objectLocationCount,
                                                 const TLayoutQualifier &layoutQualifier)
 {
     int loc = layoutQualifier.location;
     if (loc >= 0 && loc + objectLocationCount > mMaxUniformLocations)
     {
         error(location, "Uniform location out of range", "location");
     }
 }

 void TParseContext::checkYuvIsNotSpecified(const TSourceLoc &location, bool yuv)
 {
     if (yuv != false)
     {
         error(location, "invalid layout qualifier: only valid on program outputs", "yuv");
     }
 }

 void TParseContext::functionCallRValueLValueErrorCheck(const TFunction *fnCandidate,
                                                        TIntermAggregate *fnCall)
 {
     for (size_t i = 0; i < fnCandidate->getParamCount(); ++i)
     {
         TQualifier qual = fnCandidate->getParam(i).type->getQualifier();
         TIntermTyped *argument = (*(fnCall->getSequence()))[i]->getAsTyped();
         if (!IsImage(argument->getBasicType()) && (IsQualifierUnspecified(qual) || qual == EvqIn ||
                                                    qual == EvqInOut || qual == EvqConstReadOnly))
         {
             if (argument->getMemoryQualifier().writeonly)
             {
                 error(argument->getLine(),
                       "Writeonly value cannot be passed for 'in' or 'inout' parameters.",
                       fnCall->getFunctionSymbolInfo()->getName().c_str());
                 return;
             }
         }
         if (qual == EvqOut || qual == EvqInOut)
         {
             if (!checkCanBeLValue(argument->getLine(), "assign", argument))
             {
                 error(argument->getLine(),
                       "Constant value cannot be passed for 'out' or 'inout' parameters.",
                       fnCall->getFunctionSymbolInfo()->getName().c_str());
                 return;
             }
         }
     }
 }

 void TParseContext::checkInvariantVariableQualifier(bool invariant,
                                                     const TQualifier qualifier,
                                                     const TSourceLoc &invariantLocation)
 {
     if (!invariant)
         return;

     if (mShaderVersion < 300)
     {
         // input variables in the fragment shader can be also qualified as invariant
         if (!sh::CanBeInvariantESSL1(qualifier))
         {
             error(invariantLocation, "Cannot be qualified as invariant.", "invariant");
         }
     }
     else
     {
         if (!sh::CanBeInvariantESSL3OrGreater(qualifier))
         {
             error(invariantLocation, "Cannot be qualified as invariant.", "invariant");
         }
     }
 }

 bool TParseContext::supportsExtension(TExtension extension)
 {
     const TExtensionBehavior &extbehavior   = extensionBehavior();
     TExtensionBehavior::const_iterator iter = extbehavior.find(extension);
     return (iter != extbehavior.end());
 }

 bool TParseContext::isExtensionEnabled(TExtension extension) const
 {
     return IsExtensionEnabled(extensionBehavior(), extension);
 }

 void TParseContext::handleExtensionDirective(const TSourceLoc &loc,
                                              const char *extName,
                                              const char *behavior)
 {
     pp::SourceLocation srcLoc;
     srcLoc.file = loc.first_file;
     srcLoc.line = loc.first_line;
     mDirectiveHandler.handleExtension(srcLoc, extName, behavior);
 }

 void TParseContext::handlePragmaDirective(const TSourceLoc &loc,
                                           const char *name,
                                           const char *value,
                                           bool stdgl)
 {
     pp::SourceLocation srcLoc;
     srcLoc.file = loc.first_file;
     srcLoc.line = loc.first_line;
     mDirectiveHandler.handlePragma(srcLoc, name, value, stdgl);
 }

 sh::WorkGroupSize TParseContext::getComputeShaderLocalSize() const
 {
     sh::WorkGroupSize result;
     for (size_t i = 0u; i < result.size(); ++i)
     {
         if (mComputeShaderLocalSizeDeclared && mComputeShaderLocalSize[i] == -1)
         {
             result[i] = 1;
         }
         else
         {
             result[i] = mComputeShaderLocalSize[i];
         }
     }
     return result;
 }

 TIntermConstantUnion *TParseContext::addScalarLiteral(const TConstantUnion *constantUnion,
                                                       const TSourceLoc &line)
 {
     TIntermConstantUnion *node = new TIntermConstantUnion(
         constantUnion, TType(constantUnion->getType(), EbpUndefined, EvqConst));
     node->setLine(line);
     return node;
 }

 /////////////////////////////////////////////////////////////////////////////////
 //
 // Non-Errors.
 //
 /////////////////////////////////////////////////////////////////////////////////

 const TVariable *TParseContext::getNamedVariable(const TSourceLoc &location,
                                                  const TString *name,
                                                  const TSymbol *symbol)
 {
     if (!symbol)
     {
         error(location, "undeclared identifier", name->c_str());
         return nullptr;
     }

     if (!symbol->isVariable())
     {
         error(location, "variable expected", name->c_str());
         return nullptr;
     }

     const TVariable *variable = static_cast<const TVariable *>(symbol);

     if (variable->getExtension() != TExtension::UNDEFINED)
     {
         checkCanUseExtension(location, variable->getExtension());
     }

     // Reject shaders using both gl_FragData and gl_FragColor
     TQualifier qualifier = variable->getType().getQualifier();
     if (qualifier == EvqFragData || qualifier == EvqSecondaryFragDataEXT)
     {
         mUsesFragData = true;
     }
     else if (qualifier == EvqFragColor || qualifier == EvqSecondaryFragColorEXT)
     {
         mUsesFragColor = true;
     }
     if (qualifier == EvqSecondaryFragDataEXT || qualifier == EvqSecondaryFragColorEXT)
     {
         mUsesSecondaryOutputs = true;
     }

     // This validation is not quite correct - it's only an error to write to
     // both FragData and FragColor. For simplicity, and because users shouldn't
     // be rewarded for reading from undefined varaibles, return an error
     // if they are both referenced, rather than assigned.
     if (mUsesFragData && mUsesFragColor)
     {
         const char *errorMessage = "cannot use both gl_FragData and gl_FragColor";
         if (mUsesSecondaryOutputs)
         {
             errorMessage =
                 "cannot use both output variable sets (gl_FragData, gl_SecondaryFragDataEXT)"
                 " and (gl_FragColor, gl_SecondaryFragColorEXT)";
         }
         error(location, errorMessage, name->c_str());
     }

     // GLSL ES 3.1 Revision 4, 7.1.3 Compute Shader Special Variables
     if (getShaderType() == GL_COMPUTE_SHADER && !mComputeShaderLocalSizeDeclared &&
         qualifier == EvqWorkGroupSize)
     {
         error(location,
               "It is an error to use gl_WorkGroupSize before declaring the local group size",
               "gl_WorkGroupSize");
     }
     return variable;
 }

 TIntermTyped *TParseContext::parseVariableIdentifier(const TSourceLoc &location,
                                                      const TString *name,
                                                      const TSymbol *symbol)
 {
     const TVariable *variable = getNamedVariable(location, name, symbol);

     if (!variable)
     {
         TIntermTyped *node = CreateZeroNode(TType(EbtFloat, EbpHigh, EvqConst));
         node->setLine(location);
         return node;
     }

     const TType &variableType = variable->getType();
     TIntermTyped *node = nullptr;

     if (variable->getConstPointer())
     {
         const TConstantUnion *constArray = variable->getConstPointer();
         node                             = new TIntermConstantUnion(constArray, variableType);
     }
     else if (variableType.getQualifier() == EvqWorkGroupSize && mComputeShaderLocalSizeDeclared)
     {
         // gl_WorkGroupSize can be used to size arrays according to the ESSL 3.10.4 spec, so it
         // needs to be added to the AST as a constant and not as a symbol.
         sh::WorkGroupSize workGroupSize = getComputeShaderLocalSize();
         TConstantUnion *constArray      = new TConstantUnion[3];
         for (size_t i = 0; i < 3; ++i)
         {
             constArray[i].setUConst(static_cast<unsigned int>(workGroupSize[i]));
         }

         ASSERT(variableType.getBasicType() == EbtUInt);
         ASSERT(variableType.getObjectSize() == 3);

         TType type(variableType);
         type.setQualifier(EvqConst);
         node = new TIntermConstantUnion(constArray, type);
     }
     else if ((mGeometryShaderInputPrimitiveType != EptUndefined) &&
              (variableType.getQualifier() == EvqPerVertexIn))
     {
         ASSERT(mGeometryShaderInputArraySize > 0u);

         node = new TIntermSymbol(variable->getUniqueId(), variable->getName(), variableType);
         node->getTypePointer()->sizeOutermostUnsizedArray(mGeometryShaderInputArraySize);
     }
     else
     {
         node = new TIntermSymbol(variable->getUniqueId(), variable->getName(), variableType);
     }
     ASSERT(node != nullptr);
     node->setLine(location);
     return node;
 }

 // Initializers show up in several places in the grammar.  Have one set of
 // code to handle them here.
 //
 // Returns true on success.
 bool TParseContext::executeInitializer(const TSourceLoc &line,
                                        const TString &identifier,
                                        TType type,
                                        TIntermTyped *initializer,
                                        TIntermBinary **initNode)
 {
     ASSERT(initNode != nullptr);
     ASSERT(*initNode == nullptr);

     TVariable *variable = nullptr;
     if (type.isUnsizedArray())
     {
         // In case initializer is not an array or type has more dimensions than initializer, this
         // will default to setting array sizes to 1. We have not checked yet whether the initializer
         // actually is an array or not. Having a non-array initializer for an unsized array will
         // result in an error later, so we don't generate an error message here.
         type.sizeUnsizedArrays(initializer->getType().getArraySizes());
     }
     if (!declareVariable(line, identifier, type, &variable))
     {
         return false;
     }

     bool globalInitWarning = false;
     if (symbolTable.atGlobalLevel() &&
         !ValidateGlobalInitializer(initializer, this, &globalInitWarning))
     {
         // Error message does not completely match behavior with ESSL 1.00, but
         // we want to steer developers towards only using constant expressions.
         error(line, "global variable initializers must be constant expressions", "=");
         return false;
     }
     if (globalInitWarning)
     {
         warning(
             line,
             "global variable initializers should be constant expressions "
             "(uniforms and globals are allowed in global initializers for legacy compatibility)",
             "=");
     }

     //
     // identifier must be of type constant, a global, or a temporary
     //
     TQualifier qualifier = variable->getType().getQualifier();
     if ((qualifier != EvqTemporary) && (qualifier != EvqGlobal) && (qualifier != EvqConst))
     {
         error(line, " cannot initialize this type of qualifier ",
               variable->getType().getQualifierString());
         return false;
     }
     //
     // test for and propagate constant
     //

     if (qualifier == EvqConst)
     {
         if (qualifier != initializer->getType().getQualifier())
         {
             std::stringstream reasonStream;
             reasonStream << "assigning non-constant to '" << variable->getType().getCompleteString()
                          << "'";
             std::string reason = reasonStream.str();
             error(line, reason.c_str(), "=");
             variable->getType().setQualifier(EvqTemporary);
             return false;
         }
         if (type != initializer->getType())
         {
             error(line, " non-matching types for const initializer ",
                   variable->getType().getQualifierString());
             variable->getType().setQualifier(EvqTemporary);
             return false;
         }

         // Save the constant folded value to the variable if possible. For example array
         // initializers are not folded, since that way copying the array literal to multiple places
         // in the shader is avoided.
         // TODO(oetuaho@nvidia.com): Consider constant folding array initialization in cases where
         // it would be beneficial.
         if (initializer->getAsConstantUnion())
         {
             variable->shareConstPointer(initializer->getAsConstantUnion()->getUnionArrayPointer());
             ASSERT(*initNode == nullptr);
             return true;
         }
         else if (initializer->getAsSymbolNode())
         {
             const TSymbol *symbol =
                 symbolTable.find(initializer->getAsSymbolNode()->getSymbol(), 0);
             const TVariable *tVar = static_cast<const TVariable *>(symbol);

             const TConstantUnion *constArray = tVar->getConstPointer();
             if (constArray)
             {
                 variable->shareConstPointer(constArray);
                 ASSERT(*initNode == nullptr);
                 return true;
             }
         }
     }

     TIntermSymbol *intermSymbol =
         new TIntermSymbol(variable->getUniqueId(), variable->getName(), variable->getType());
     intermSymbol->setLine(line);
     *initNode = createAssign(EOpInitialize, intermSymbol, initializer, line);
     if (*initNode == nullptr)
     {
         assignError(line, "=", intermSymbol->getCompleteString(), initializer->getCompleteString());
         return false;
     }

     return true;
 }

 TIntermNode *TParseContext::addConditionInitializer(const TPublicType &pType,
                                                     const TString &identifier,
                                                     TIntermTyped *initializer,
                                                     const TSourceLoc &loc)
 {
     checkIsScalarBool(loc, pType);
     TIntermBinary *initNode = nullptr;
     TType type(pType);
     if (executeInitializer(loc, identifier, type, initializer, &initNode))
     {
         // The initializer is valid. The init condition needs to have a node - either the
         // initializer node, or a constant node in case the initialized variable is const and won't
         // be recorded in the AST.
         if (initNode == nullptr)
         {
             return initializer;
         }
         else
         {
             TIntermDeclaration *declaration = new TIntermDeclaration();
             declaration->appendDeclarator(initNode);
             return declaration;
         }
     }
     return nullptr;
 }

 TIntermNode *TParseContext::addLoop(TLoopType type,
                                     TIntermNode *init,
                                     TIntermNode *cond,
                                     TIntermTyped *expr,
                                     TIntermNode *body,
                                     const TSourceLoc &line)
 {
     TIntermNode *node       = nullptr;
     TIntermTyped *typedCond = nullptr;
     if (cond)
     {
         typedCond = cond->getAsTyped();
     }
     if (cond == nullptr || typedCond)
     {
         if (type == ELoopDoWhile)
         {
             checkIsScalarBool(line, typedCond);
         }
         // In the case of other loops, it was checked before that the condition is a scalar boolean.
         ASSERT(mDiagnostics->numErrors() > 0 || typedCond == nullptr ||
                (typedCond->getBasicType() == EbtBool && !typedCond->isArray() &&
                 !typedCond->isVector()));

         node = new TIntermLoop(type, init, typedCond, expr, EnsureBlock(body));
         node->setLine(line);
         return node;
     }

     ASSERT(type != ELoopDoWhile);

     TIntermDeclaration *declaration = cond->getAsDeclarationNode();
     ASSERT(declaration);
     TIntermBinary *declarator = declaration->getSequence()->front()->getAsBinaryNode();
     ASSERT(declarator->getLeft()->getAsSymbolNode());

     // The condition is a declaration. In the AST representation we don't support declarations as
     // loop conditions. Wrap the loop to a block that declares the condition variable and contains
     // the loop.
     TIntermBlock *block = new TIntermBlock();

     TIntermDeclaration *declareCondition = new TIntermDeclaration();
     declareCondition->appendDeclarator(declarator->getLeft()->deepCopy());
     block->appendStatement(declareCondition);

     TIntermBinary *conditionInit = new TIntermBinary(EOpAssign, declarator->getLeft()->deepCopy(),
                                                      declarator->getRight()->deepCopy());
     TIntermLoop *loop = new TIntermLoop(type, init, conditionInit, expr, EnsureBlock(body));
     block->appendStatement(loop);
     loop->setLine(line);
     block->setLine(line);
     return block;
 }

 TIntermNode *TParseContext::addIfElse(TIntermTyped *cond,
                                       TIntermNodePair code,
                                       const TSourceLoc &loc)
 {
     bool isScalarBool = checkIsScalarBool(loc, cond);

     // For compile time constant conditions, prune the code now.
     if (isScalarBool && cond->getAsConstantUnion())
     {
         if (cond->getAsConstantUnion()->getBConst(0) == true)
         {
             return EnsureBlock(code.node1);
         }
         else
         {
             return EnsureBlock(code.node2);
         }
     }

     TIntermIfElse *node = new TIntermIfElse(cond, EnsureBlock(code.node1), EnsureBlock(code.node2));
     node->setLine(loc);

     return node;
 }

 void TParseContext::addFullySpecifiedType(TPublicType *typeSpecifier)
 {
     checkPrecisionSpecified(typeSpecifier->getLine(), typeSpecifier->precision,
                             typeSpecifier->getBasicType());

     if (mShaderVersion < 300 && typeSpecifier->array)
     {
         error(typeSpecifier->getLine(), "not supported", "first-class array");
         typeSpecifier->clearArrayness();
     }
 }

 TPublicType TParseContext::addFullySpecifiedType(const TTypeQualifierBuilder &typeQualifierBuilder,
                                                  const TPublicType &typeSpecifier)
 {
     TTypeQualifier typeQualifier = typeQualifierBuilder.getVariableTypeQualifier(mDiagnostics);

     TPublicType returnType     = typeSpecifier;
     returnType.qualifier       = typeQualifier.qualifier;
     returnType.invariant       = typeQualifier.invariant;
     returnType.layoutQualifier = typeQualifier.layoutQualifier;
     returnType.memoryQualifier = typeQualifier.memoryQualifier;
     returnType.precision       = typeSpecifier.precision;

     if (typeQualifier.precision != EbpUndefined)
     {
         returnType.precision = typeQualifier.precision;
     }

     checkPrecisionSpecified(typeSpecifier.getLine(), returnType.precision,
                             typeSpecifier.getBasicType());

     checkInvariantVariableQualifier(returnType.invariant, returnType.qualifier,
                                     typeSpecifier.getLine());

     checkWorkGroupSizeIsNotSpecified(typeSpecifier.getLine(), returnType.layoutQualifier);

     if (mShaderVersion < 300)
     {
         if (typeSpecifier.array)
         {
             error(typeSpecifier.getLine(), "not supported", "first-class array");
             returnType.clearArrayness();
         }

         if (returnType.qualifier == EvqAttribute &&
             (typeSpecifier.getBasicType() == EbtBool || typeSpecifier.getBasicType() == EbtInt))
         {
             error(typeSpecifier.getLine(), "cannot be bool or int",
                   getQualifierString(returnType.qualifier));
         }

         if ((returnType.qualifier == EvqVaryingIn || returnType.qualifier == EvqVaryingOut) &&
             (typeSpecifier.getBasicType() == EbtBool || typeSpecifier.getBasicType() == EbtInt))
         {
             error(typeSpecifier.getLine(), "cannot be bool or int",
                   getQualifierString(returnType.qualifier));
         }
     }
     else
     {
         if (!returnType.layoutQualifier.isEmpty())
         {
             checkIsAtGlobalLevel(typeSpecifier.getLine(), "layout");
         }
         if (sh::IsVarying(returnType.qualifier) || returnType.qualifier == EvqVertexIn ||
             returnType.qualifier == EvqFragmentOut)
         {
             checkInputOutputTypeIsValidES3(returnType.qualifier, typeSpecifier,
                                            typeSpecifier.getLine());
         }
         if (returnType.qualifier == EvqComputeIn)
         {
             error(typeSpecifier.getLine(), "'in' can be only used to specify the local group size",
                   "in");
         }
     }

     return returnType;
 }

 void TParseContext::checkInputOutputTypeIsValidES3(const TQualifier qualifier,
                                                    const TPublicType &type,
                                                    const TSourceLoc &qualifierLocation)
 {
     // An input/output variable can never be bool or a sampler. Samplers are checked elsewhere.
     if (type.getBasicType() == EbtBool)
     {
         error(qualifierLocation, "cannot be bool", getQualifierString(qualifier));
     }

     // Specific restrictions apply for vertex shader inputs and fragment shader outputs.
     switch (qualifier)
     {
         case EvqVertexIn:
             // ESSL 3.00 section 4.3.4
             if (type.array)
             {
                 error(qualifierLocation, "cannot be array", getQualifierString(qualifier));
             }
             // Vertex inputs with a struct type are disallowed in nonEmptyDeclarationErrorCheck
             return;
         case EvqFragmentOut:
             // ESSL 3.00 section 4.3.6
             if (type.typeSpecifierNonArray.isMatrix())
             {
                 error(qualifierLocation, "cannot be matrix", getQualifierString(qualifier));
             }
             // Fragment outputs with a struct type are disallowed in nonEmptyDeclarationErrorCheck
             return;
         default:
             break;
     }

     // Vertex shader outputs / fragment shader inputs have a different, slightly more lenient set of
     // restrictions.
     bool typeContainsIntegers =
         (type.getBasicType() == EbtInt || type.getBasicType() == EbtUInt ||
          type.isStructureContainingType(EbtInt) || type.isStructureContainingType(EbtUInt));
     if (typeContainsIntegers && qualifier != EvqFlatIn && qualifier != EvqFlatOut)
     {
         error(qualifierLocation, "must use 'flat' interpolation here",
               getQualifierString(qualifier));
     }

     if (type.getBasicType() == EbtStruct)
     {
         // ESSL 3.00 sections 4.3.4 and 4.3.6.
         // These restrictions are only implied by the ESSL 3.00 spec, but
         // the ESSL 3.10 spec lists these restrictions explicitly.
         if (type.array)
         {
             error(qualifierLocation, "cannot be an array of structures",
                   getQualifierString(qualifier));
         }
         if (type.isStructureContainingArrays())
         {
             error(qualifierLocation, "cannot be a structure containing an array",
                   getQualifierString(qualifier));
         }
         if (type.isStructureContainingType(EbtStruct))
         {
             error(qualifierLocation, "cannot be a structure containing a structure",
                   getQualifierString(qualifier));
         }
         if (type.isStructureContainingType(EbtBool))
         {
             error(qualifierLocation, "cannot be a structure containing a bool",
                   getQualifierString(qualifier));
         }
     }
 }

 void TParseContext::checkLocalVariableConstStorageQualifier(const TQualifierWrapperBase &qualifier)
 {
     if (qualifier.getType() == QtStorage)
     {
         const TStorageQualifierWrapper &storageQualifier =
             static_cast<const TStorageQualifierWrapper &>(qualifier);
         if (!declaringFunction() && storageQualifier.getQualifier() != EvqConst &&
             !symbolTable.atGlobalLevel())
         {
             error(storageQualifier.getLine(),
                   "Local variables can only use the const storage qualifier.",
                   storageQualifier.getQualifierString().c_str());
         }
     }
 }

 void TParseContext::checkMemoryQualifierIsNotSpecified(const TMemoryQualifier &memoryQualifier,
                                                        const TSourceLoc &location)
 {
     const std::string reason(
         "Only allowed with shader storage blocks, variables declared within shader storage blocks "
         "and variables declared as image types.");
     if (memoryQualifier.readonly)
     {
         error(location, reason.c_str(), "readonly");
     }
     if (memoryQualifier.writeonly)
     {
         error(location, reason.c_str(), "writeonly");
     }
     if (memoryQualifier.coherent)
     {
         error(location, reason.c_str(), "coherent");
     }
     if (memoryQualifier.restrictQualifier)
     {
         error(location, reason.c_str(), "restrict");
     }
     if (memoryQualifier.volatileQualifier)
     {
         error(location, reason.c_str(), "volatile");
     }
 }

 // Make sure there is no offset overlapping, and store the newly assigned offset to "type" in
 // intermediate tree.
 void TParseContext::checkAtomicCounterOffsetDoesNotOverlap(bool forceAppend,
                                                            const TSourceLoc &loc,
                                                            TType *type)
 {
     if (!IsAtomicCounter(type->getBasicType()))
     {
         return;
     }

     const size_t size = type->isArray() ? kAtomicCounterArrayStride * type->getArraySizeProduct()
                                         : kAtomicCounterSize;
     TLayoutQualifier layoutQualifier = type->getLayoutQualifier();
     auto &bindingState               = mAtomicCounterBindingStates[layoutQualifier.binding];
     int offset;
     if (layoutQualifier.offset == -1 || forceAppend)
     {
         offset = bindingState.appendSpan(size);
     }
     else
     {
         offset = bindingState.insertSpan(layoutQualifier.offset, size);
     }
     if (offset == -1)
     {
         error(loc, "Offset overlapping", "atomic counter");
         return;
     }
     layoutQualifier.offset = offset;
     type->setLayoutQualifier(layoutQualifier);
 }

 void TParseContext::checkGeometryShaderInputAndSetArraySize(const TSourceLoc &location,
                                                             const char *token,
                                                             TType *type)
 {
     if (IsGeometryShaderInput(mShaderType, type->getQualifier()))
     {
         if (type->isArray() && type->getOutermostArraySize() == 0u)
         {
             // Set size for the unsized geometry shader inputs if they are declared after a valid
             // input primitive declaration.
             if (mGeometryShaderInputPrimitiveType != EptUndefined)
             {
                 ASSERT(mGeometryShaderInputArraySize > 0u);
                 type->sizeOutermostUnsizedArray(mGeometryShaderInputArraySize);
             }
             else
             {
                 // [GLSL ES 3.2 SPEC Chapter 4.4.1.2]
                 // An input can be declared without an array size if there is a previous layout
                 // which specifies the size.
                 error(location,
                       "Missing a valid input primitive declaration before declaring an unsized "
                       "array input",
                       token);
             }
         }
         else if (type->isArray())
         {
             setGeometryShaderInputArraySize(type->getOutermostArraySize(), location);
         }
         else
         {
             error(location, "Geometry shader input variable must be declared as an array", token);
         }
     }
 }

 TIntermDeclaration *TParseContext::parseSingleDeclaration(
     TPublicType &publicType,
     const TSourceLoc &identifierOrTypeLocation,
     const TString &identifier)
 {
     TType type(publicType);
     if ((mCompileOptions & SH_FLATTEN_PRAGMA_STDGL_INVARIANT_ALL) &&
         mDirectiveHandler.pragma().stdgl.invariantAll)
     {
         TQualifier qualifier = type.getQualifier();

         // The directive handler has already taken care of rejecting invalid uses of this pragma
         // (for example, in ESSL 3.00 fragment shaders), so at this point, flatten it into all
         // affected variable declarations:
         //
         // 1. Built-in special variables which are inputs to the fragment shader. (These are handled
         // elsewhere, in TranslatorGLSL.)
         //
         // 2. Outputs from vertex shaders in ESSL 1.00 and 3.00 (EvqVaryingOut and EvqVertexOut). It
         // is actually less likely that there will be bugs in the handling of ESSL 3.00 shaders, but
         // the way this is currently implemented we have to enable this compiler option before
         // parsing the shader and determining the shading language version it uses. If this were
         // implemented as a post-pass, the workaround could be more targeted.
         //
         // 3. Inputs in ESSL 1.00 fragment shaders (EvqVaryingIn). This is somewhat in violation of
         // the specification, but there are desktop OpenGL drivers that expect that this is the
         // behavior of the #pragma when specified in ESSL 1.00 fragment shaders.
         if (qualifier == EvqVaryingOut || qualifier == EvqVertexOut || qualifier == EvqVaryingIn)
         {
             type.setInvariant(true);
         }
     }

     checkGeometryShaderInputAndSetArraySize(identifierOrTypeLocation, identifier.c_str(), &type);

     declarationQualifierErrorCheck(publicType.qualifier, publicType.layoutQualifier,
                                    identifierOrTypeLocation);

     bool emptyDeclaration = (identifier == "");
     mDeferredNonEmptyDeclarationErrorCheck = emptyDeclaration;

     TIntermSymbol *symbol = nullptr;
     if (emptyDeclaration)
     {
         emptyDeclarationErrorCheck(type, identifierOrTypeLocation);
         // In most cases we don't need to create a symbol node for an empty declaration.
         // But if the empty declaration is declaring a struct type, the symbol node will store that.
         if (type.getBasicType() == EbtStruct)
         {
             symbol = new TIntermSymbol(symbolTable.getEmptySymbolId(), "", type);
         }
         else if (IsAtomicCounter(publicType.getBasicType()))
         {
             setAtomicCounterBindingDefaultOffset(publicType, identifierOrTypeLocation);
         }
     }
     else
     {
         nonEmptyDeclarationErrorCheck(publicType, identifierOrTypeLocation);

         checkCanBeDeclaredWithoutInitializer(identifierOrTypeLocation, identifier, &type);

         checkAtomicCounterOffsetDoesNotOverlap(false, identifierOrTypeLocation, &type);

         TVariable *variable = nullptr;
         declareVariable(identifierOrTypeLocation, identifier, type, &variable);

         if (variable)
         {
             symbol = new TIntermSymbol(variable->getUniqueId(), identifier, type);
         }
     }

     TIntermDeclaration *declaration = new TIntermDeclaration();
     declaration->setLine(identifierOrTypeLocation);
     if (symbol)
     {
         symbol->setLine(identifierOrTypeLocation);
         declaration->appendDeclarator(symbol);
     }
     return declaration;
 }

 TIntermDeclaration *TParseContext::parseSingleArrayDeclaration(TPublicType &elementType,
                                                                const TSourceLoc &identifierLocation,
                                                                const TString &identifier,
                                                                const TSourceLoc &indexLocation,
                                                                unsigned int arraySize)
 {
     mDeferredNonEmptyDeclarationErrorCheck = false;

     declarationQualifierErrorCheck(elementType.qualifier, elementType.layoutQualifier,
                                    identifierLocation);

     nonEmptyDeclarationErrorCheck(elementType, identifierLocation);

     checkIsValidTypeAndQualifierForArray(indexLocation, elementType);

     TType arrayType(elementType);
     arrayType.makeArray(arraySize);

     checkGeometryShaderInputAndSetArraySize(indexLocation, identifier.c_str(), &arrayType);

     checkCanBeDeclaredWithoutInitializer(identifierLocation, identifier, &arrayType);

     checkAtomicCounterOffsetDoesNotOverlap(false, identifierLocation, &arrayType);

     TVariable *variable = nullptr;
     declareVariable(identifierLocation, identifier, arrayType, &variable);

     TIntermDeclaration *declaration = new TIntermDeclaration();
     declaration->setLine(identifierLocation);

     if (variable)
     {
         TIntermSymbol *symbol = new TIntermSymbol(variable->getUniqueId(), identifier, arrayType);
         symbol->setLine(identifierLocation);
         declaration->appendDeclarator(symbol);
     }

     return declaration;
 }

 TIntermDeclaration *TParseContext::parseSingleInitDeclaration(const TPublicType &publicType,
                                                               const TSourceLoc &identifierLocation,
                                                               const TString &identifier,
                                                               const TSourceLoc &initLocation,
                                                               TIntermTyped *initializer)
 {
     mDeferredNonEmptyDeclarationErrorCheck = false;

     declarationQualifierErrorCheck(publicType.qualifier, publicType.layoutQualifier,
                                    identifierLocation);

     nonEmptyDeclarationErrorCheck(publicType, identifierLocation);

     TIntermDeclaration *declaration = new TIntermDeclaration();
     declaration->setLine(identifierLocation);

     TIntermBinary *initNode = nullptr;
     TType type(publicType);
     if (executeInitializer(identifierLocation, identifier, type, initializer, &initNode))
     {
         if (initNode)
         {
             declaration->appendDeclarator(initNode);
         }
     }
     return declaration;
 }

 TIntermDeclaration *TParseContext::parseSingleArrayInitDeclaration(
     TPublicType &elementType,
     const TSourceLoc &identifierLocation,
     const TString &identifier,
     const TSourceLoc &indexLocation,
     unsigned int arraySize,
     const TSourceLoc &initLocation,
     TIntermTyped *initializer)
 {
     mDeferredNonEmptyDeclarationErrorCheck = false;

     declarationQualifierErrorCheck(elementType.qualifier, elementType.layoutQualifier,
                                    identifierLocation);

     nonEmptyDeclarationErrorCheck(elementType, identifierLocation);

     checkIsValidTypeAndQualifierForArray(indexLocation, elementType);

     TType arrayType(elementType);
     arrayType.makeArray(arraySize);

     TIntermDeclaration *declaration = new TIntermDeclaration();
     declaration->setLine(identifierLocation);

     // initNode will correspond to the whole of "type b[n] = initializer".
     TIntermBinary *initNode = nullptr;
     if (executeInitializer(identifierLocation, identifier, arrayType, initializer, &initNode))
     {
         if (initNode)
         {
             declaration->appendDeclarator(initNode);
         }
     }

     return declaration;
 }

 TIntermInvariantDeclaration *TParseContext::parseInvariantDeclaration(
     const TTypeQualifierBuilder &typeQualifierBuilder,
     const TSourceLoc &identifierLoc,
     const TString *identifier,
     const TSymbol *symbol)
 {
     TTypeQualifier typeQualifier = typeQualifierBuilder.getVariableTypeQualifier(mDiagnostics);

     if (!typeQualifier.invariant)
     {
         error(identifierLoc, "Expected invariant", identifier->c_str());
         return nullptr;
     }
     if (!checkIsAtGlobalLevel(identifierLoc, "invariant varying"))
     {
         return nullptr;
     }
     if (!symbol)
     {
         error(identifierLoc, "undeclared identifier declared as invariant", identifier->c_str());
         return nullptr;
     }
     if (!IsQualifierUnspecified(typeQualifier.qualifier))
     {
         error(identifierLoc, "invariant declaration specifies qualifier",
               getQualifierString(typeQualifier.qualifier));
     }
     if (typeQualifier.precision != EbpUndefined)
     {
         error(identifierLoc, "invariant declaration specifies precision",
               getPrecisionString(typeQualifier.precision));
     }
     if (!typeQualifier.layoutQualifier.isEmpty())
     {
         error(identifierLoc, "invariant declaration specifies layout", "'layout'");
     }

     const TVariable *variable = getNamedVariable(identifierLoc, identifier, symbol);
     if (!variable)
     {
         return nullptr;
     }
     const TType &type = variable->getType();

     checkInvariantVariableQualifier(typeQualifier.invariant, type.getQualifier(),
                                     typeQualifier.line);
     checkMemoryQualifierIsNotSpecified(typeQualifier.memoryQualifier, typeQualifier.line);

     symbolTable.addInvariantVarying(std::string(identifier->c_str()));

     TIntermSymbol *intermSymbol = new TIntermSymbol(variable->getUniqueId(), *identifier, type);
     intermSymbol->setLine(identifierLoc);

     return new TIntermInvariantDeclaration(intermSymbol, identifierLoc);
 }

 void TParseContext::parseDeclarator(TPublicType &publicType,
                                     const TSourceLoc &identifierLocation,
                                     const TString &identifier,
                                     TIntermDeclaration *declarationOut)
 {
     // If the declaration starting this declarator list was empty (example: int,), some checks were
     // not performed.
     if (mDeferredNonEmptyDeclarationErrorCheck)
     {
         nonEmptyDeclarationErrorCheck(publicType, identifierLocation);
         mDeferredNonEmptyDeclarationErrorCheck = false;
     }

     checkDeclaratorLocationIsNotSpecified(identifierLocation, publicType);

     TVariable *variable = nullptr;
     TType type(publicType);

     checkGeometryShaderInputAndSetArraySize(identifierLocation, identifier.c_str(), &type);

     checkCanBeDeclaredWithoutInitializer(identifierLocation, identifier, &type);

     checkAtomicCounterOffsetDoesNotOverlap(true, identifierLocation, &type);

     declareVariable(identifierLocation, identifier, type, &variable);

     if (variable)
     {
         TIntermSymbol *symbol = new TIntermSymbol(variable->getUniqueId(), identifier, type);
         symbol->setLine(identifierLocation);
         declarationOut->appendDeclarator(symbol);
     }
 }

 void TParseContext::parseArrayDeclarator(TPublicType &elementType,
                                          const TSourceLoc &identifierLocation,
                                          const TString &identifier,
                                          const TSourceLoc &arrayLocation,
                                          unsigned int arraySize,
                                          TIntermDeclaration *declarationOut)
 {
     // If the declaration starting this declarator list was empty (example: int,), some checks were
     // not performed.
     if (mDeferredNonEmptyDeclarationErrorCheck)
     {
         nonEmptyDeclarationErrorCheck(elementType, identifierLocation);
         mDeferredNonEmptyDeclarationErrorCheck = false;
     }

     checkDeclaratorLocationIsNotSpecified(identifierLocation, elementType);

     if (checkIsValidTypeAndQualifierForArray(arrayLocation, elementType))
     {
         TType arrayType(elementType);
         arrayType.makeArray(arraySize);

         checkGeometryShaderInputAndSetArraySize(identifierLocation, identifier.c_str(), &arrayType);

         checkCanBeDeclaredWithoutInitializer(identifierLocation, identifier, &arrayType);

         checkAtomicCounterOffsetDoesNotOverlap(true, identifierLocation, &arrayType);

         TVariable *variable = nullptr;
         declareVariable(identifierLocation, identifier, arrayType, &variable);

         if (variable)
         {
             TIntermSymbol *symbol =
                 new TIntermSymbol(variable->getUniqueId(), identifier, arrayType);
             symbol->setLine(identifierLocation);
             declarationOut->appendDeclarator(symbol);
         }
     }
 }

 void TParseContext::parseInitDeclarator(const TPublicType &publicType,
                                         const TSourceLoc &identifierLocation,
                                         const TString &identifier,
                                         const TSourceLoc &initLocation,
                                         TIntermTyped *initializer,
                                         TIntermDeclaration *declarationOut)
 {
     // If the declaration starting this declarator list was empty (example: int,), some checks were
     // not performed.
     if (mDeferredNonEmptyDeclarationErrorCheck)
     {
         nonEmptyDeclarationErrorCheck(publicType, identifierLocation);
         mDeferredNonEmptyDeclarationErrorCheck = false;
     }

     checkDeclaratorLocationIsNotSpecified(identifierLocation, publicType);

     TIntermBinary *initNode = nullptr;
     TType type(publicType);
     if (executeInitializer(identifierLocation, identifier, type, initializer, &initNode))
     {
         //
         // build the intermediate representation
         //
         if (initNode)
         {
             declarationOut->appendDeclarator(initNode);
         }
     }
 }

 void TParseContext::parseArrayInitDeclarator(const TPublicType &elementType,
                                              const TSourceLoc &identifierLocation,
                                              const TString &identifier,
                                              const TSourceLoc &indexLocation,
                                              unsigned int arraySize,
                                              const TSourceLoc &initLocation,
                                              TIntermTyped *initializer,
                                              TIntermDeclaration *declarationOut)
 {
     // If the declaration starting this declarator list was empty (example: int,), some checks were
     // not performed.
     if (mDeferredNonEmptyDeclarationErrorCheck)
     {
         nonEmptyDeclarationErrorCheck(elementType, identifierLocation);
         mDeferredNonEmptyDeclarationErrorCheck = false;
     }

     checkDeclaratorLocationIsNotSpecified(identifierLocation, elementType);

     checkIsValidTypeAndQualifierForArray(indexLocation, elementType);

     TType arrayType(elementType);
     arrayType.makeArray(arraySize);

     // initNode will correspond to the whole of "b[n] = initializer".
     TIntermBinary *initNode = nullptr;
     if (executeInitializer(identifierLocation, identifier, arrayType, initializer, &initNode))
     {
         if (initNode)
         {
             declarationOut->appendDeclarator(initNode);
         }
     }
 }

 TIntermNode *TParseContext::addEmptyStatement(const TSourceLoc &location)
 {
     // It's simpler to parse an empty statement as a constant expression rather than having a
     // different type of node just for empty statements, that will be pruned from the AST anyway.
     TIntermNode *node = CreateZeroNode(TType(EbtInt, EbpMedium));
     node->setLine(location);
     return node;
 }

 void TParseContext::setAtomicCounterBindingDefaultOffset(const TPublicType &publicType,
                                                          const TSourceLoc &location)
 {
     const TLayoutQualifier &layoutQualifier = publicType.layoutQualifier;
     checkAtomicCounterBindingIsValid(location, layoutQualifier.binding);
     if (layoutQualifier.binding == -1 || layoutQualifier.offset == -1)
     {
         error(location, "Requires both binding and offset", "layout");
         return;
     }
     mAtomicCounterBindingStates[layoutQualifier.binding].setDefaultOffset(layoutQualifier.offset);
 }

 void TParseContext::parseDefaultPrecisionQualifier(const TPrecision precision,
                                                    const TPublicType &type,
                                                    const TSourceLoc &loc)
 {
     if ((precision == EbpHigh) && (getShaderType() == GL_FRAGMENT_SHADER) &&
         !getFragmentPrecisionHigh())
     {
         error(loc, "precision is not supported in fragment shader", "highp");
     }

     if (!CanSetDefaultPrecisionOnType(type))
     {
         error(loc, "illegal type argument for default precision qualifier",
               getBasicString(type.getBasicType()));
         return;
     }
     symbolTable.setDefaultPrecision(type.getBasicType(), precision);
 }

 bool TParseContext::checkPrimitiveTypeMatchesTypeQualifier(const TTypeQualifier &typeQualifier)
 {
     switch (typeQualifier.layoutQualifier.primitiveType)
     {
         case EptLines:
         case EptLinesAdjacency:
         case EptTriangles:
         case EptTrianglesAdjacency:
             return typeQualifier.qualifier == EvqGeometryIn;

         case EptLineStrip:
         case EptTriangleStrip:
             return typeQualifier.qualifier == EvqGeometryOut;

         case EptPoints:
             return true;

         default:
             UNREACHABLE();
             return false;
     }
 }

 void TParseContext::setGeometryShaderInputArraySize(unsigned int inputArraySize,
                                                     const TSourceLoc &line)
 {
     if (mGeometryShaderInputArraySize == 0u)
     {
         mGeometryShaderInputArraySize = inputArraySize;
     }
     else if (mGeometryShaderInputArraySize != inputArraySize)
     {
         error(line,
               "Array size or input primitive declaration doesn't match the size of earlier sized "
               "array inputs.",
               "layout");
     }
 }

 bool TParseContext::parseGeometryShaderInputLayoutQualifier(const TTypeQualifier &typeQualifier)
 {
     ASSERT(typeQualifier.qualifier == EvqGeometryIn);

     const TLayoutQualifier &layoutQualifier = typeQualifier.layoutQualifier;

     if (layoutQualifier.maxVertices != -1)
     {
         error(typeQualifier.line,
               "max_vertices can only be declared in 'out' layout in a geometry shader", "layout");
         return false;
     }

     // Set mGeometryInputPrimitiveType if exists
     if (layoutQualifier.primitiveType != EptUndefined)
     {
         if (!checkPrimitiveTypeMatchesTypeQualifier(typeQualifier))
         {
             error(typeQualifier.line, "invalid primitive type for 'in' layout", "layout");
             return false;
         }

         if (mGeometryShaderInputPrimitiveType == EptUndefined)
         {
             mGeometryShaderInputPrimitiveType = layoutQualifier.primitiveType;
             setGeometryShaderInputArraySize(
                 GetGeometryShaderInputArraySize(mGeometryShaderInputPrimitiveType),
                 typeQualifier.line);
         }
         else if (mGeometryShaderInputPrimitiveType != layoutQualifier.primitiveType)
         {
             error(typeQualifier.line, "primitive doesn't match earlier input primitive declaration",
                   "layout");
             return false;
         }
     }

     // Set mGeometryInvocations if exists
     if (layoutQualifier.invocations > 0)
     {
         if (mGeometryShaderInvocations == 0)
         {
             mGeometryShaderInvocations = layoutQualifier.invocations;
         }
         else if (mGeometryShaderInvocations != layoutQualifier.invocations)
         {
             error(typeQualifier.line, "invocations contradicts to the earlier declaration",
                   "layout");
             return false;
         }
     }

     return true;
 }

 bool TParseContext::parseGeometryShaderOutputLayoutQualifier(const TTypeQualifier &typeQualifier)
 {
     ASSERT(typeQualifier.qualifier == EvqGeometryOut);

     const TLayoutQualifier &layoutQualifier = typeQualifier.layoutQualifier;

     if (layoutQualifier.invocations > 0)
     {
         error(typeQualifier.line,
               "invocations can only be declared in 'in' layout in a geometry shader", "layout");
         return false;
     }

     // Set mGeometryOutputPrimitiveType if exists
     if (layoutQualifier.primitiveType != EptUndefined)
     {
         if (!checkPrimitiveTypeMatchesTypeQualifier(typeQualifier))
         {
             error(typeQualifier.line, "invalid primitive type for 'out' layout", "layout");
             return false;
         }

         if (mGeometryShaderOutputPrimitiveType == EptUndefined)
         {
             mGeometryShaderOutputPrimitiveType = layoutQualifier.primitiveType;
         }
         else if (mGeometryShaderOutputPrimitiveType != layoutQualifier.primitiveType)
         {
             error(typeQualifier.line,
                   "primitive doesn't match earlier output primitive declaration", "layout");
             return false;
         }
     }

     // Set mGeometryMaxVertices if exists
     if (layoutQualifier.maxVertices > -1)
     {
         if (mGeometryShaderMaxVertices == -1)
         {
             mGeometryShaderMaxVertices = layoutQualifier.maxVertices;
         }
         else if (mGeometryShaderMaxVertices != layoutQualifier.maxVertices)
         {
             error(typeQualifier.line, "max_vertices contradicts to the earlier declaration",
                   "layout");
             return false;
         }
     }

     return true;
 }

 void TParseContext::parseGlobalLayoutQualifier(const TTypeQualifierBuilder &typeQualifierBuilder)
 {
     TTypeQualifier typeQualifier = typeQualifierBuilder.getVariableTypeQualifier(mDiagnostics);
     const TLayoutQualifier layoutQualifier = typeQualifier.layoutQualifier;

     checkInvariantVariableQualifier(typeQualifier.invariant, typeQualifier.qualifier,
                                     typeQualifier.line);

     // It should never be the case, but some strange parser errors can send us here.
     if (layoutQualifier.isEmpty())
     {
         error(typeQualifier.line, "Error during layout qualifier parsing.", "?");
         return;
     }

     if (!layoutQualifier.isCombinationValid())
     {
         error(typeQualifier.line, "invalid layout qualifier combination", "layout");
         return;
     }

     checkBindingIsNotSpecified(typeQualifier.line, layoutQualifier.binding);

     checkMemoryQualifierIsNotSpecified(typeQualifier.memoryQualifier, typeQualifier.line);

     checkInternalFormatIsNotSpecified(typeQualifier.line, layoutQualifier.imageInternalFormat);

     checkYuvIsNotSpecified(typeQualifier.line, layoutQualifier.yuv);

     checkOffsetIsNotSpecified(typeQualifier.line, layoutQualifier.offset);

     checkStd430IsForShaderStorageBlock(typeQualifier.line, layoutQualifier.blockStorage,
                                        typeQualifier.qualifier);

     if (typeQualifier.qualifier == EvqComputeIn)
     {
         if (mComputeShaderLocalSizeDeclared &&
             !layoutQualifier.isLocalSizeEqual(mComputeShaderLocalSize))
         {
             error(typeQualifier.line, "Work group size does not match the previous declaration",
                   "layout");
             return;
         }

         if (mShaderVersion < 310)
         {
             error(typeQualifier.line, "in type qualifier supported in GLSL ES 3.10 only", "layout");
             return;
         }

         if (!layoutQualifier.localSize.isAnyValueSet())
         {
             error(typeQualifier.line, "No local work group size specified", "layout");
             return;
         }

         const TVariable *maxComputeWorkGroupSize = static_cast<const TVariable *>(
             symbolTable.findBuiltIn("gl_MaxComputeWorkGroupSize", mShaderVersion));

         const TConstantUnion *maxComputeWorkGroupSizeData =
             maxComputeWorkGroupSize->getConstPointer();

         for (size_t i = 0u; i < layoutQualifier.localSize.size(); ++i)
         {
             if (layoutQualifier.localSize[i] != -1)
             {
                 mComputeShaderLocalSize[i]             = layoutQualifier.localSize[i];
                 const int maxComputeWorkGroupSizeValue = maxComputeWorkGroupSizeData[i].getIConst();
                 if (mComputeShaderLocalSize[i] < 1 ||
                     mComputeShaderLocalSize[i] > maxComputeWorkGroupSizeValue)
                 {
                     std::stringstream reasonStream;
                     reasonStream << "invalid value: Value must be at least 1 and no greater than "
                                  << maxComputeWorkGroupSizeValue;
                     const std::string &reason = reasonStream.str();

                     error(typeQualifier.line, reason.c_str(), getWorkGroupSizeString(i));
                     return;
                 }
             }
         }

         mComputeShaderLocalSizeDeclared = true;
     }
     else if (typeQualifier.qualifier == EvqGeometryIn)
     {
         if (mShaderVersion < 310)
         {
             error(typeQualifier.line, "in type qualifier supported in GLSL ES 3.10 only", "layout");
             return;
         }

         if (!parseGeometryShaderInputLayoutQualifier(typeQualifier))
         {
             return;
         }
     }
     else if (typeQualifier.qualifier == EvqGeometryOut)
     {
         if (mShaderVersion < 310)
         {
             error(typeQualifier.line, "out type qualifier supported in GLSL ES 3.10 only",
                   "layout");
             return;
         }

         if (!parseGeometryShaderOutputLayoutQualifier(typeQualifier))
         {
             return;
         }
     }
     else if (isExtensionEnabled(TExtension::OVR_multiview) &&
              typeQualifier.qualifier == EvqVertexIn)
     {
         // This error is only specified in WebGL, but tightens unspecified behavior in the native
         // specification.
         if (mNumViews != -1 && layoutQualifier.numViews != mNumViews)
         {
             error(typeQualifier.line, "Number of views does not match the previous declaration",
                   "layout");
             return;
         }

         if (layoutQualifier.numViews == -1)
         {
             error(typeQualifier.line, "No num_views specified", "layout");
             return;
         }

         if (layoutQualifier.numViews > mMaxNumViews)
         {
             error(typeQualifier.line, "num_views greater than the value of GL_MAX_VIEWS_OVR",
                   "layout");
             return;
         }

         mNumViews = layoutQualifier.numViews;
     }
     else
     {
         if (!checkWorkGroupSizeIsNotSpecified(typeQualifier.line, layoutQualifier))
         {
             return;
         }

         if (typeQualifier.qualifier != EvqUniform && typeQualifier.qualifier != EvqBuffer)
         {
             error(typeQualifier.line, "invalid qualifier: global layout can only be set for blocks",
                   getQualifierString(typeQualifier.qualifier));
             return;
         }

         if (mShaderVersion < 300)
         {
             error(typeQualifier.line, "layout qualifiers supported in GLSL ES 3.00 and above",
                   "layout");
             return;
         }

         checkLocationIsNotSpecified(typeQualifier.line, layoutQualifier);

         if (layoutQualifier.matrixPacking != EmpUnspecified)
         {
             if (typeQualifier.qualifier == EvqUniform)
             {
                 mDefaultUniformMatrixPacking = layoutQualifier.matrixPacking;
             }
             else if (typeQualifier.qualifier == EvqBuffer)
             {
                 mDefaultBufferMatrixPacking = layoutQualifier.matrixPacking;
             }
         }

         if (layoutQualifier.blockStorage != EbsUnspecified)
         {
             if (typeQualifier.qualifier == EvqUniform)
             {
                 mDefaultUniformBlockStorage = layoutQualifier.blockStorage;
             }
             else if (typeQualifier.qualifier == EvqBuffer)
             {
                 mDefaultBufferBlockStorage = layoutQualifier.blockStorage;
             }
         }
     }
 }

 TIntermFunctionPrototype *TParseContext::createPrototypeNodeFromFunction(
     const TFunction &function,
     const TSourceLoc &location,
     bool insertParametersToSymbolTable)
 {
     checkIsNotReserved(location, function.getName());

     TIntermFunctionPrototype *prototype =
         new TIntermFunctionPrototype(function.getReturnType(), TSymbolUniqueId(function));
     // TODO(oetuaho@nvidia.com): Instead of converting the function information here, the node could
     // point to the data that already exists in the symbol table.
     prototype->getFunctionSymbolInfo()->setFromFunction(function);
     prototype->setLine(location);

     for (size_t i = 0; i < function.getParamCount(); i++)
     {
         const TConstParameter &param = function.getParam(i);

         TIntermSymbol *symbol = nullptr;

         // If the parameter has no name, it's not an error, just don't add it to symbol table (could
         // be used for unused args).
         if (param.name != nullptr)
         {
             // Insert the parameter in the symbol table.
             if (insertParametersToSymbolTable)
             {
                 TVariable *variable = symbolTable.declareVariable(param.name, *param.type);
                 if (variable)
                 {
                     symbol = new TIntermSymbol(variable->getUniqueId(), variable->getName(),
                                                variable->getType());
                 }
                 else
                 {
                     error(location, "redefinition", param.name->c_str());
                 }
             }
             // Unsized type of a named parameter should have already been checked and sanitized.
             ASSERT(!param.type->isUnsizedArray());
         }
         else
         {
             if (param.type->isUnsizedArray())
             {
                 error(location, "function parameter array must be sized at compile time", "[]");
                 // We don't need to size the arrays since the parameter is unnamed and hence
                 // inaccessible.
             }
         }
         if (!symbol)
         {
             // The parameter had no name or declaring the symbol failed - either way, add a nameless
             // symbol.
             symbol = new TIntermSymbol(symbolTable.getEmptySymbolId(), "", *param.type);
         }
         symbol->setLine(location);
         prototype->appendParameter(symbol);
     }
     return prototype;
 }

 TIntermFunctionPrototype *TParseContext::addFunctionPrototypeDeclaration(
     const TFunction &parsedFunction,
     const TSourceLoc &location)
 {
     // Note: function found from the symbol table could be the same as parsedFunction if this is the
     // first declaration. Either way the instance in the symbol table is used to track whether the
     // function is declared multiple times.
     TFunction *function = static_cast<TFunction *>(
         symbolTable.find(parsedFunction.getMangledName(), getShaderVersion()));
     if (function->hasPrototypeDeclaration() && mShaderVersion == 100)
     {
         // ESSL 1.00.17 section 4.2.7.
         // Doesn't apply to ESSL 3.00.4: see section 4.2.3.
         error(location, "duplicate function prototype declarations are not allowed", "function");
     }
     function->setHasPrototypeDeclaration();

     TIntermFunctionPrototype *prototype =
         createPrototypeNodeFromFunction(*function, location, false);

     symbolTable.pop();

     if (!symbolTable.atGlobalLevel())
     {
         // ESSL 3.00.4 section 4.2.4.
         error(location, "local function prototype declarations are not allowed", "function");
     }

     return prototype;
 }

 TIntermFunctionDefinition *TParseContext::addFunctionDefinition(
     TIntermFunctionPrototype *functionPrototype,
     TIntermBlock *functionBody,
     const TSourceLoc &location)
 {
     // Check that non-void functions have at least one return statement.
     if (mCurrentFunctionType->getBasicType() != EbtVoid && !mFunctionReturnsValue)
     {
         error(location, "function does not return a value:",
               functionPrototype->getFunctionSymbolInfo()->getName().c_str());
     }

     if (functionBody == nullptr)
     {
         functionBody = new TIntermBlock();
         functionBody->setLine(location);
     }
     TIntermFunctionDefinition *functionNode =
         new TIntermFunctionDefinition(functionPrototype, functionBody);
     functionNode->setLine(location);

     symbolTable.pop();
     return functionNode;
 }

 void TParseContext::parseFunctionDefinitionHeader(const TSourceLoc &location,
                                                   TFunction **function,
                                                   TIntermFunctionPrototype **prototypeOut)
 {
     ASSERT(function);
     ASSERT(*function);
     const TSymbol *builtIn =
         symbolTable.findBuiltIn((*function)->getMangledName(), getShaderVersion());

     if (builtIn)
     {
         error(location, "built-in functions cannot be redefined", (*function)->getName().c_str());
     }
     else
     {
         TFunction *prevDec = static_cast<TFunction *>(
             symbolTable.find((*function)->getMangledName(), getShaderVersion()));

         // Note: 'prevDec' could be 'function' if this is the first time we've seen function as it
         // would have just been put in the symbol table. Otherwise, we're looking up an earlier
         // occurance.
         if (*function != prevDec)
         {
             // Swap the parameters of the previous declaration to the parameters of the function
             // definition (parameter names may differ).
             prevDec->swapParameters(**function);

             // The function definition will share the same symbol as any previous declaration.
             *function = prevDec;
         }

         if ((*function)->isDefined())
         {
             error(location, "function already has a body", (*function)->getName().c_str());
         }

         (*function)->setDefined();
     }

     // Remember the return type for later checking for return statements.
     mCurrentFunctionType  = &((*function)->getReturnType());
     mFunctionReturnsValue = false;

     *prototypeOut = createPrototypeNodeFromFunction(**function, location, true);
     setLoopNestingLevel(0);
 }

 TFunction *TParseContext::parseFunctionDeclarator(const TSourceLoc &location, TFunction *function)
 {
     //
     // We don't know at this point whether this is a function definition or a prototype.
     // The definition production code will check for redefinitions.
     // In the case of ESSL 1.00 the prototype production code will also check for redeclarations.
     //
     // Return types and parameter qualifiers must match in all redeclarations, so those are checked
     // here.
     //
     TFunction *prevDec =
         static_cast<TFunction *>(symbolTable.find(function->getMangledName(), getShaderVersion()));

     for (size_t i = 0u; i < function->getParamCount(); ++i)
     {
         auto &param = function->getParam(i);
         if (param.type->isStructSpecifier())
         {
             // ESSL 3.00.6 section 12.10.
             error(location, "Function parameter type cannot be a structure definition",
                   param.name->c_str());
         }
     }

     if (getShaderVersion() >= 300 &&
         symbolTable.hasUnmangledBuiltInForShaderVersion(function->getName().c_str(),
                                                         getShaderVersion()))
     {
         // With ESSL 3.00 and above, names of built-in functions cannot be redeclared as functions.
         // Therefore overloading or redefining builtin functions is an error.
         error(location, "Name of a built-in function cannot be redeclared as function",
               function->getName().c_str());
     }
     else if (prevDec)
     {
         if (prevDec->getReturnType() != function->getReturnType())
         {
             error(location, "function must have the same return type in all of its declarations",
                   function->getReturnType().getBasicString());
         }
         for (size_t i = 0; i < prevDec->getParamCount(); ++i)
         {
             if (prevDec->getParam(i).type->getQualifier() !=
                 function->getParam(i).type->getQualifier())
             {
                 error(location,
                       "function must have the same parameter qualifiers in all of its declarations",
                       function->getParam(i).type->getQualifierString());
             }
         }
     }

     //
     // Check for previously declared variables using the same name.
     //
     TSymbol *prevSym = symbolTable.find(function->getName(), getShaderVersion());
     if (prevSym)
     {
         if (!prevSym->isFunction())
         {
             error(location, "redefinition of a function", function->getName().c_str());
         }
     }
     else
     {
         // Insert the unmangled name to detect potential future redefinition as a variable.
         symbolTable.getOuterLevel()->insertUnmangled(function);
     }

     // We're at the inner scope level of the function's arguments and body statement.
     // Add the function prototype to the surrounding scope instead.
     symbolTable.getOuterLevel()->insert(function);

     // Raise error message if main function takes any parameters or return anything other than void
     if (function->getName() == "main")
     {
         if (function->getParamCount() > 0)
         {
             error(location, "function cannot take any parameter(s)", "main");
         }
         if (function->getReturnType().getBasicType() != EbtVoid)
         {
             error(location, "main function cannot return a value",
                   function->getReturnType().getBasicString());
         }
     }

     //
     // If this is a redeclaration, it could also be a definition, in which case, we want to use the
     // variable names from this one, and not the one that's
     // being redeclared.  So, pass back up this declaration, not the one in the symbol table.
     //
     return function;
 }

 TFunction *TParseContext::parseFunctionHeader(const TPublicType &type,
                                               const TString *name,
                                               const TSourceLoc &location)
 {
     if (type.qualifier != EvqGlobal && type.qualifier != EvqTemporary)
     {
         error(location, "no qualifiers allowed for function return",
               getQualifierString(type.qualifier));
     }
     if (!type.layoutQualifier.isEmpty())
     {
         error(location, "no qualifiers allowed for function return", "layout");
     }
     // make sure an opaque type is not involved as well...
     std::string reason(getBasicString(type.getBasicType()));
     reason += "s can't be function return values";
     checkIsNotOpaqueType(location, type.typeSpecifierNonArray, reason.c_str());
     if (mShaderVersion < 300)
     {
         // Array return values are forbidden, but there's also no valid syntax for declaring array
         // return values in ESSL 1.00.
         ASSERT(type.arraySize == 0 || mDiagnostics->numErrors() > 0);

         if (type.isStructureContainingArrays())
         {
             // ESSL 1.00.17 section 6.1 Function Definitions
             error(location, "structures containing arrays can't be function return values",
                   TType(type).getCompleteString().c_str());
         }
     }

     // Add the function as a prototype after parsing it (we do not support recursion)
     return new TFunction(&symbolTable, name, new TType(type));
 }

 TFunction *TParseContext::addNonConstructorFunc(const TString *name, const TSourceLoc &loc)
 {
     const TType *returnType = TCache::getType(EbtVoid, EbpUndefined);
     return new TFunction(&symbolTable, name, returnType);
 }

 TFunction *TParseContext::addConstructorFunc(const TPublicType &publicType)
 {
     if (mShaderVersion < 300 && publicType.array)
     {
         error(publicType.getLine(), "array constructor supported in GLSL ES 3.00 and above only",
               "[]");
     }
     if (publicType.isStructSpecifier())
     {
         error(publicType.getLine(), "constructor can't be a structure definition",
               getBasicString(publicType.getBasicType()));
     }

     TType *type = new TType(publicType);
     if (!type->canBeConstructed())
     {
         error(publicType.getLine(), "cannot construct this type",
               getBasicString(publicType.getBasicType()));
         type->setBasicType(EbtFloat);
     }

     return new TFunction(&symbolTable, nullptr, type, EOpConstruct);
 }

 void TParseContext::checkIsNotUnsizedArray(const TSourceLoc &line,
                                            const char *errorMessage,
                                            const char *token,
                                            TType *arrayType)
 {
     if (arrayType->isUnsizedArray())
     {
         error(line, errorMessage, token);
         arrayType->sizeUnsizedArrays(TVector<unsigned int>());
     }
 }

 TParameter TParseContext::parseParameterDeclarator(TType *type,
                                                    const TString *name,
                                                    const TSourceLoc &nameLoc)
 {
     ASSERT(type);
     checkIsNotUnsizedArray(nameLoc, "function parameter array must specify a size", name->c_str(),
                            type);
     if (type->getBasicType() == EbtVoid)
     {
         error(nameLoc, "illegal use of type 'void'", name->c_str());
     }
     checkIsNotReserved(nameLoc, *name);
     TParameter param = {name, type};
     return param;
 }

 TParameter TParseContext::parseParameterDeclarator(const TPublicType &publicType,
                                                    const TString *name,
                                                    const TSourceLoc &nameLoc)
 {
     TType *type = new TType(publicType);
     return parseParameterDeclarator(type, name, nameLoc);
 }

 TParameter TParseContext::parseParameterArrayDeclarator(const TString *name,
                                                         const TSourceLoc &nameLoc,
                                                         unsigned int arraySize,
                                                         const TSourceLoc &arrayLoc,
                                                         TPublicType *elementType)
 {
     checkArrayElementIsNotArray(arrayLoc, *elementType);
     TType *arrayType = new TType(*elementType);
     arrayType->makeArray(arraySize);
     return parseParameterDeclarator(arrayType, name, nameLoc);
 }

 bool TParseContext::checkUnsizedArrayConstructorArgumentDimensionality(TIntermSequence *arguments,
                                                                        TType type,
                                                                        const TSourceLoc &line)
 {
     if (arguments->empty())
     {
         error(line, "implicitly sized array constructor must have at least one argument", "[]");
         return false;
     }
     for (TIntermNode *arg : *arguments)
     {
         TIntermTyped *element = arg->getAsTyped();
         ASSERT(element);
         size_t dimensionalityFromElement = element->getType().getArraySizes().size() + 1u;
         if (dimensionalityFromElement > type.getArraySizes().size())
         {
             error(line, "constructing from a non-dereferenced array", "constructor");
             return false;
         }
         else if (dimensionalityFromElement < type.getArraySizes().size())
         {
             if (dimensionalityFromElement == 1u)
             {
                 error(line, "implicitly sized array of arrays constructor argument is not an array",
                       "constructor");
             }
             else
             {
                 error(line,
                       "implicitly sized array of arrays constructor argument dimensionality is too "
                       "low",
                       "constructor");
             }
             return false;
         }
     }
     return true;
 }

 // This function is used to test for the correctness of the parameters passed to various constructor
 // functions and also convert them to the right datatype if it is allowed and required.
 //
 // Returns a node to add to the tree regardless of if an error was generated or not.
 //
 TIntermTyped *TParseContext::addConstructor(TIntermSequence *arguments,
                                             TType type,
                                             const TSourceLoc &line)
 {
     if (type.isUnsizedArray())
     {
         if (!checkUnsizedArrayConstructorArgumentDimensionality(arguments, type, line))
         {
             type.sizeUnsizedArrays(TVector<unsigned int>());
             return CreateZeroNode(type);
         }
         TIntermTyped *firstElement = arguments->at(0)->getAsTyped();
         ASSERT(firstElement);
         if (type.getOutermostArraySize() == 0u)
         {
             type.sizeOutermostUnsizedArray(static_cast<unsigned int>(arguments->size()));
         }
         for (size_t i = 0; i < firstElement->getType().getArraySizes().size(); ++i)
         {
             if (type.getArraySizes()[i] == 0u)
             {
                 type.setArraySize(i, firstElement->getType().getArraySizes().at(i));
             }
         }
         ASSERT(!type.isUnsizedArray());
     }

     if (!checkConstructorArguments(line, arguments, type))
     {
         return CreateZeroNode(type);
     }

     TIntermAggregate *constructorNode = TIntermAggregate::CreateConstructor(type, arguments);
     constructorNode->setLine(line);

     // TODO(oetuaho@nvidia.com): Add support for folding array constructors.
     if (!constructorNode->isArray())
     {
         return constructorNode->fold(mDiagnostics);
     }
     return constructorNode;
 }

 //
 // Interface/uniform blocks
 // TODO(jiawei.shao@intel.com): implement GL_OES_shader_io_blocks.
 //
 TIntermDeclaration *TParseContext::addInterfaceBlock(
     const TTypeQualifierBuilder &typeQualifierBuilder,
     const TSourceLoc &nameLine,
     const TString &blockName,
     TFieldList *fieldList,
     const TString *instanceName,
     const TSourceLoc &instanceLine,
     TIntermTyped *arrayIndex,
     const TSourceLoc &arrayIndexLine)
 {
     checkIsNotReserved(nameLine, blockName);

     TTypeQualifier typeQualifier = typeQualifierBuilder.getVariableTypeQualifier(mDiagnostics);

     if (mShaderVersion < 310 && typeQualifier.qualifier != EvqUniform)
     {
         error(typeQualifier.line,
               "invalid qualifier: interface blocks must be uniform in version lower than GLSL ES "
               "3.10",
               getQualifierString(typeQualifier.qualifier));
     }
     else if (typeQualifier.qualifier != EvqUniform && typeQualifier.qualifier != EvqBuffer)
     {
         error(typeQualifier.line, "invalid qualifier: interface blocks must be uniform or buffer",
               getQualifierString(typeQualifier.qualifier));
     }

     if (typeQualifier.invariant)
     {
         error(typeQualifier.line, "invalid qualifier on interface block member", "invariant");
     }

     if (typeQualifier.qualifier != EvqBuffer)
     {
         checkMemoryQualifierIsNotSpecified(typeQualifier.memoryQualifier, typeQualifier.line);
     }

     // add array index
     unsigned int arraySize = 0;
     if (arrayIndex != nullptr)
     {
         arraySize = checkIsValidArraySize(arrayIndexLine, arrayIndex);
     }

     if (mShaderVersion < 310)
     {
         checkBindingIsNotSpecified(typeQualifier.line, typeQualifier.layoutQualifier.binding);
     }
     else
     {
         checkBlockBindingIsValid(typeQualifier.line, typeQualifier.qualifier,
                                  typeQualifier.layoutQualifier.binding, arraySize);
     }

     checkYuvIsNotSpecified(typeQualifier.line, typeQualifier.layoutQualifier.yuv);

     TLayoutQualifier blockLayoutQualifier = typeQualifier.layoutQualifier;
     checkLocationIsNotSpecified(typeQualifier.line, blockLayoutQualifier);
     checkStd430IsForShaderStorageBlock(typeQualifier.line, blockLayoutQualifier.blockStorage,
                                        typeQualifier.qualifier);

     if (blockLayoutQualifier.matrixPacking == EmpUnspecified)
     {
         if (typeQualifier.qualifier == EvqUniform)
         {
             blockLayoutQualifier.matrixPacking = mDefaultUniformMatrixPacking;
         }
         else if (typeQualifier.qualifier == EvqBuffer)
         {
             blockLayoutQualifier.matrixPacking = mDefaultBufferMatrixPacking;
         }
     }

     if (blockLayoutQualifier.blockStorage == EbsUnspecified)
     {
         if (typeQualifier.qualifier == EvqUniform)
         {
             blockLayoutQualifier.blockStorage = mDefaultUniformBlockStorage;
         }
         else if (typeQualifier.qualifier == EvqBuffer)
         {
             blockLayoutQualifier.blockStorage = mDefaultBufferBlockStorage;
         }
     }

     checkWorkGroupSizeIsNotSpecified(nameLine, blockLayoutQualifier);

     checkInternalFormatIsNotSpecified(nameLine, blockLayoutQualifier.imageInternalFormat);

     if (!symbolTable.declareInterfaceBlockName(&blockName))
     {
         error(nameLine, "redefinition of an interface block name", blockName.c_str());
     }

     // check for sampler types and apply layout qualifiers
     for (size_t memberIndex = 0; memberIndex < fieldList->size(); ++memberIndex)
     {
         TField *field    = (*fieldList)[memberIndex];
         TType *fieldType = field->type();
         if (IsOpaqueType(fieldType->getBasicType()))
         {
             std::string reason("unsupported type - ");
             reason += fieldType->getBasicString();
             reason += " types are not allowed in interface blocks";
             error(field->line(), reason.c_str(), fieldType->getBasicString());
         }

         const TQualifier qualifier = fieldType->getQualifier();
         switch (qualifier)
         {
             case EvqGlobal:
                 break;
             case EvqUniform:
                 if (typeQualifier.qualifier == EvqBuffer)
                 {
                     error(field->line(), "invalid qualifier on shader storage block member",
                           getQualifierString(qualifier));
                 }
                 break;
             case EvqBuffer:
                 if (typeQualifier.qualifier == EvqUniform)
                 {
                     error(field->line(), "invalid qualifier on uniform block member",
                           getQualifierString(qualifier));
                 }
                 break;
             default:
                 error(field->line(), "invalid qualifier on interface block member",
                       getQualifierString(qualifier));
                 break;
         }

         if (fieldType->isInvariant())
         {
             error(field->line(), "invalid qualifier on interface block member", "invariant");
         }

         // check layout qualifiers
         TLayoutQualifier fieldLayoutQualifier = fieldType->getLayoutQualifier();
         checkLocationIsNotSpecified(field->line(), fieldLayoutQualifier);
         checkBindingIsNotSpecified(field->line(), fieldLayoutQualifier.binding);

         if (fieldLayoutQualifier.blockStorage != EbsUnspecified)
         {
             error(field->line(), "invalid layout qualifier: cannot be used here",
                   getBlockStorageString(fieldLayoutQualifier.blockStorage));
         }

         if (fieldLayoutQualifier.matrixPacking == EmpUnspecified)
         {
             fieldLayoutQualifier.matrixPacking = blockLayoutQualifier.matrixPacking;
         }
         else if (!fieldType->isMatrix() && fieldType->getBasicType() != EbtStruct)
         {
             warning(field->line(),
                     "extraneous layout qualifier: only has an effect on matrix types",
                     getMatrixPackingString(fieldLayoutQualifier.matrixPacking));
         }

         fieldType->setLayoutQualifier(fieldLayoutQualifier);

         if (typeQualifier.qualifier == EvqBuffer)
         {
             // set memory qualifiers
             // GLSL ES 3.10 session 4.9 [Memory Access Qualifiers]. When a block declaration is
             // qualified with a memory qualifier, it is as if all of its members were declared with
             // the same memory qualifier.
             const TMemoryQualifier &blockMemoryQualifier = typeQualifier.memoryQualifier;
             TMemoryQualifier fieldMemoryQualifier        = fieldType->getMemoryQualifier();
             fieldMemoryQualifier.readonly |= blockMemoryQualifier.readonly;
             fieldMemoryQualifier.writeonly |= blockMemoryQualifier.writeonly;
             fieldMemoryQualifier.coherent |= blockMemoryQualifier.coherent;
             fieldMemoryQualifier.restrictQualifier |= blockMemoryQualifier.restrictQualifier;
             fieldMemoryQualifier.volatileQualifier |= blockMemoryQualifier.volatileQualifier;
             // TODO(jiajia.qin@intel.com): Decide whether if readonly and writeonly buffer variable
             // is legal. See bug https://github.com/KhronosGroup/OpenGL-API/issues/7
             fieldType->setMemoryQualifier(fieldMemoryQualifier);
         }
     }

     TInterfaceBlock *interfaceBlock =
         new TInterfaceBlock(&blockName, fieldList, instanceName, blockLayoutQualifier);
     TType interfaceBlockType(interfaceBlock, typeQualifier.qualifier, blockLayoutQualifier);
     if (arrayIndex != nullptr)
     {
         interfaceBlockType.makeArray(arraySize);
     }

     TString symbolName = "";
     const TSymbolUniqueId *symbolId = nullptr;

     if (!instanceName)
     {
         // define symbols for the members of the interface block
         for (size_t memberIndex = 0; memberIndex < fieldList->size(); ++memberIndex)
         {
             TField *field    = (*fieldList)[memberIndex];
             TType *fieldType = field->type();

             // set parent pointer of the field variable
             fieldType->setInterfaceBlock(interfaceBlock);

             TVariable *fieldVariable = symbolTable.declareVariable(&field->name(), *fieldType);

             if (fieldVariable)
             {
                 fieldVariable->setQualifier(typeQualifier.qualifier);
             }
             else
             {
                 error(field->line(), "redefinition of an interface block member name",
                       field->name().c_str());
             }
         }
         symbolId = &symbolTable.getEmptySymbolId();
     }
     else
     {
         checkIsNotReserved(instanceLine, *instanceName);

         // add a symbol for this interface block
         TVariable *instanceTypeDef = symbolTable.declareVariable(instanceName, interfaceBlockType);
         if (instanceTypeDef)
         {
             instanceTypeDef->setQualifier(typeQualifier.qualifier);
             symbolId = &instanceTypeDef->getUniqueId();
         }
         else
         {
             error(instanceLine, "redefinition of an interface block instance name",
                   instanceName->c_str());
         }
         symbolName = *instanceName;
     }

     TIntermDeclaration *declaration = nullptr;

     if (symbolId)
     {
         TIntermSymbol *blockSymbol = new TIntermSymbol(*symbolId, symbolName, interfaceBlockType);
         blockSymbol->setLine(typeQualifier.line);
         declaration = new TIntermDeclaration();
         declaration->appendDeclarator(blockSymbol);
         declaration->setLine(nameLine);
     }

     exitStructDeclaration();
     return declaration;
 }

 void TParseContext::enterStructDeclaration(const TSourceLoc &line, const TString &identifier)
 {
     ++mStructNestingLevel;

     // Embedded structure definitions are not supported per GLSL ES spec.
     // ESSL 1.00.17 section 10.9. ESSL 3.00.6 section 12.11.
     if (mStructNestingLevel > 1)
     {
         error(line, "Embedded struct definitions are not allowed", "struct");
     }
 }

 void TParseContext::exitStructDeclaration()
 {
     --mStructNestingLevel;
 }

 void TParseContext::checkIsBelowStructNestingLimit(const TSourceLoc &line, const TField &field)
 {
     if (!sh::IsWebGLBasedSpec(mShaderSpec))
     {
         return;
     }

     if (field.type()->getBasicType() != EbtStruct)
     {
         return;
     }

     // We're already inside a structure definition at this point, so add
     // one to the field's struct nesting.
     if (1 + field.type()->getDeepestStructNesting() > kWebGLMaxStructNesting)
     {
         std::stringstream reasonStream;
         reasonStream << "Reference of struct type " << field.type()->getStruct()->name().c_str()
                      << " exceeds maximum allowed nesting level of " << kWebGLMaxStructNesting;
         std::string reason = reasonStream.str();
         error(line, reason.c_str(), field.name().c_str());
         return;
     }
 }

 //
 // Parse an array index expression
 //
 TIntermTyped *TParseContext::addIndexExpression(TIntermTyped *baseExpression,
                                                 const TSourceLoc &location,
                                                 TIntermTyped *indexExpression)
 {
     if (!baseExpression->isArray() && !baseExpression->isMatrix() && !baseExpression->isVector())
     {
         if (baseExpression->getAsSymbolNode())
         {
             error(location, " left of '[' is not of type array, matrix, or vector ",
                   baseExpression->getAsSymbolNode()->getSymbol().c_str());
         }
         else
         {
             error(location, " left of '[' is not of type array, matrix, or vector ", "expression");
         }

         return CreateZeroNode(TType(EbtFloat, EbpHigh, EvqConst));
     }

     if (baseExpression->getQualifier() == EvqPerVertexIn)
     {
         ASSERT(mShaderType == GL_GEOMETRY_SHADER_OES);
         if (mGeometryShaderInputPrimitiveType == EptUndefined)
         {
             error(location, "missing input primitive declaration before indexing gl_in.", "[");
             return CreateZeroNode(TType(EbtFloat, EbpHigh, EvqConst));
         }
     }

     TIntermConstantUnion *indexConstantUnion = indexExpression->getAsConstantUnion();

     // TODO(oetuaho@nvidia.com): Get rid of indexConstantUnion == nullptr below once ANGLE is able
     // to constant fold all constant expressions. Right now we don't allow indexing interface blocks
     // or fragment outputs with expressions that ANGLE is not able to constant fold, even if the
     // index is a constant expression.
     if (indexExpression->getQualifier() != EvqConst || indexConstantUnion == nullptr)
     {
         if (baseExpression->isInterfaceBlock())
         {
             // TODO(jiawei.shao@intel.com): implement GL_OES_shader_io_blocks.
             switch (baseExpression->getQualifier())
             {
                 case EvqPerVertexIn:
                     break;
                 case EvqUniform:
                 case EvqBuffer:
                     error(location,
                           "array indexes for uniform block arrays and shader storage block arrays "
                           "must be constant integral expressions",
                           "[");
                     break;
                 default:
                     // We can reach here only in error cases.
                     ASSERT(mDiagnostics->numErrors() > 0);
                     break;
             }
         }
         else if (baseExpression->getQualifier() == EvqFragmentOut)
         {
             error(location,
                   "array indexes for fragment outputs must be constant integral expressions", "[");
         }
         else if (mShaderSpec == SH_WEBGL2_SPEC && baseExpression->getQualifier() == EvqFragData)
         {
             error(location, "array index for gl_FragData must be constant zero", "[");
         }
     }

     if (indexConstantUnion)
     {
         // If an out-of-range index is not qualified as constant, the behavior in the spec is
         // undefined. This applies even if ANGLE has been able to constant fold it (ANGLE may
         // constant fold expressions that are not constant expressions). The most compatible way to
         // handle this case is to report a warning instead of an error and force the index to be in
         // the correct range.
         bool outOfRangeIndexIsError = indexExpression->getQualifier() == EvqConst;
         int index                   = 0;
         if (indexConstantUnion->getBasicType() == EbtInt)
         {
             index = indexConstantUnion->getIConst(0);
         }
         else if (indexConstantUnion->getBasicType() == EbtUInt)
         {
             index = static_cast<int>(indexConstantUnion->getUConst(0));
         }

         int safeIndex = -1;

         if (baseExpression->isArray())
         {
             if (baseExpression->getQualifier() == EvqFragData && index > 0)
             {
                 if (!isExtensionEnabled(TExtension::EXT_draw_buffers))
                 {
                     outOfRangeError(outOfRangeIndexIsError, location,
                                     "array index for gl_FragData must be zero when "
                                     "GL_EXT_draw_buffers is disabled",
                                     "[");
                     safeIndex = 0;
                 }
             }
             // Only do generic out-of-range check if similar error hasn't already been reported.
             if (safeIndex < 0)
             {
                 safeIndex = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                                  baseExpression->getOutermostArraySize(),
                                                  "array index out of range");
             }
         }
         else if (baseExpression->isMatrix())
         {
             safeIndex = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                              baseExpression->getType().getCols(),
                                              "matrix field selection out of range");
         }
         else if (baseExpression->isVector())
         {
             safeIndex = checkIndexOutOfRange(outOfRangeIndexIsError, location, index,
                                              baseExpression->getType().getNominalSize(),
                                              "vector field selection out of range");
         }

         ASSERT(safeIndex >= 0);
         // Data of constant unions can't be changed, because it may be shared with other
         // constant unions or even builtins, like gl_MaxDrawBuffers. Instead use a new
         // sanitized object.
         if (safeIndex != index || indexConstantUnion->getBasicType() != EbtInt)
         {
             TConstantUnion *safeConstantUnion = new TConstantUnion();
             safeConstantUnion->setIConst(safeIndex);
             indexConstantUnion->replaceConstantUnion(safeConstantUnion);
             indexConstantUnion->getTypePointer()->setBasicType(EbtInt);
         }

         TIntermBinary *node = new TIntermBinary(EOpIndexDirect, baseExpression, indexExpression);
         node->setLine(location);
         return node->fold(mDiagnostics);
     }
     else
     {
         TIntermBinary *node = new TIntermBinary(EOpIndexIndirect, baseExpression, indexExpression);
         node->setLine(location);
         // Indirect indexing can never be constant folded.
         return node;
     }
 }

 int TParseContext::checkIndexOutOfRange(bool outOfRangeIndexIsError,
                                         const TSourceLoc &location,
                                         int index,
                                         int arraySize,
                                         const char *reason)
 {
     if (index >= arraySize || index < 0)
     {
         std::stringstream reasonStream;
         reasonStream << reason << " '" << index << "'";
         std::string token = reasonStream.str();
         outOfRangeError(outOfRangeIndexIsError, location, reason, "[]");
         if (index < 0)
         {
             return 0;
         }
         else
         {
             return arraySize - 1;
         }
     }
     return index;
 }

 TIntermTyped *TParseContext::addFieldSelectionExpression(TIntermTyped *baseExpression,
                                                          const TSourceLoc &dotLocation,
                                                          const TString &fieldString,
                                                          const TSourceLoc &fieldLocation)
 {
     if (baseExpression->isArray())
     {
         error(fieldLocation, "cannot apply dot operator to an array", ".");
         return baseExpression;
     }

     if (baseExpression->isVector())
     {
         TVector<int> fieldOffsets;
         if (!parseVectorFields(fieldLocation, fieldString, baseExpression->getNominalSize(),
                                &fieldOffsets))
         {
             fieldOffsets.resize(1);
             fieldOffsets[0] = 0;
         }
         TIntermSwizzle *node = new TIntermSwizzle(baseExpression, fieldOffsets);
         node->setLine(dotLocation);

         return node->fold();
     }
     else if (baseExpression->getBasicType() == EbtStruct)
     {
         const TFieldList &fields = baseExpression->getType().getStruct()->fields();
         if (fields.empty())
         {
             error(dotLocation, "structure has no fields", "Internal Error");
             return baseExpression;
         }
         else
         {
             bool fieldFound = false;
             unsigned int i;
             for (i = 0; i < fields.size(); ++i)
             {
                 if (fields[i]->name() == fieldString)
                 {
                     fieldFound = true;
                     break;
                 }
             }
             if (fieldFound)
             {
                 TIntermTyped *index = CreateIndexNode(i);
                 index->setLine(fieldLocation);
                 TIntermBinary *node =
                     new TIntermBinary(EOpIndexDirectStruct, baseExpression, index);
                 node->setLine(dotLocation);
                 return node->fold(mDiagnostics);
             }
             else
             {
                 error(dotLocation, " no such field in structure", fieldString.c_str());
                 return baseExpression;
             }
         }
     }
     else if (baseExpression->isInterfaceBlock())
     {
         const TFieldList &fields = baseExpression->getType().getInterfaceBlock()->fields();
         if (fields.empty())
         {
             error(dotLocation, "interface block has no fields", "Internal Error");
             return baseExpression;
         }
         else
         {
             bool fieldFound = false;
             unsigned int i;
             for (i = 0; i < fields.size(); ++i)
             {
                 if (fields[i]->name() == fieldString)
                 {
                     fieldFound = true;
                     break;
                 }
             }
             if (fieldFound)
             {
                 TIntermTyped *index = CreateIndexNode(i);
                 index->setLine(fieldLocation);
                 TIntermBinary *node =
                     new TIntermBinary(EOpIndexDirectInterfaceBlock, baseExpression, index);
                 node->setLine(dotLocation);
                 // Indexing interface blocks can never be constant folded.
                 return node;
             }
             else
             {
                 error(dotLocation, " no such field in interface block", fieldString.c_str());
                 return baseExpression;
             }
         }
     }
     else
     {
         if (mShaderVersion < 300)
         {
             error(dotLocation, " field selection requires structure or vector on left hand side",
                   fieldString.c_str());
         }
         else
         {
             error(dotLocation,
                   " field selection requires structure, vector, or interface block on left hand "
                   "side",
                   fieldString.c_str());
         }
         return baseExpression;
     }
 }

 TLayoutQualifier TParseContext::parseLayoutQualifier(const TString &qualifierType,
                                                      const TSourceLoc &qualifierTypeLine)
 {
     TLayoutQualifier qualifier = TLayoutQualifier::create();

     if (qualifierType == "shared")
     {
         if (sh::IsWebGLBasedSpec(mShaderSpec))
         {
             error(qualifierTypeLine, "Only std140 layout is allowed in WebGL", "shared");
         }
         qualifier.blockStorage = EbsShared;
     }
     else if (qualifierType == "packed")
     {
         if (sh::IsWebGLBasedSpec(mShaderSpec))
         {
             error(qualifierTypeLine, "Only std140 layout is allowed in WebGL", "packed");
         }
         qualifier.blockStorage = EbsPacked;
     }
     else if (qualifierType == "std430")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.blockStorage = EbsStd430;
     }
     else if (qualifierType == "std140")
     {
         qualifier.blockStorage = EbsStd140;
     }
     else if (qualifierType == "row_major")
     {
         qualifier.matrixPacking = EmpRowMajor;
     }
     else if (qualifierType == "column_major")
     {
         qualifier.matrixPacking = EmpColumnMajor;
     }
     else if (qualifierType == "location")
     {
         error(qualifierTypeLine, "invalid layout qualifier: location requires an argument",
               qualifierType.c_str());
     }
     else if (qualifierType == "yuv" && isExtensionEnabled(TExtension::EXT_YUV_target) &&
              mShaderType == GL_FRAGMENT_SHADER)
     {
         qualifier.yuv = true;
     }
     else if (qualifierType == "rgba32f")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA32F;
     }
     else if (qualifierType == "rgba16f")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA16F;
     }
     else if (qualifierType == "r32f")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifR32F;
     }
     else if (qualifierType == "rgba8")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA8;
     }
     else if (qualifierType == "rgba8_snorm")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA8_SNORM;
     }
     else if (qualifierType == "rgba32i")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA32I;
     }
     else if (qualifierType == "rgba16i")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA16I;
     }
     else if (qualifierType == "rgba8i")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA8I;
     }
     else if (qualifierType == "r32i")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifR32I;
     }
     else if (qualifierType == "rgba32ui")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA32UI;
     }
     else if (qualifierType == "rgba16ui")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA16UI;
     }
     else if (qualifierType == "rgba8ui")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifRGBA8UI;
     }
     else if (qualifierType == "r32ui")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.imageInternalFormat = EiifR32UI;
     }
     else if (qualifierType == "points" && isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptPoints;
     }
     else if (qualifierType == "lines" && isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptLines;
     }
     else if (qualifierType == "lines_adjacency" &&
              isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptLinesAdjacency;
     }
     else if (qualifierType == "triangles" && isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptTriangles;
     }
     else if (qualifierType == "triangles_adjacency" &&
              isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptTrianglesAdjacency;
     }
     else if (qualifierType == "line_strip" && isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptLineStrip;
     }
     else if (qualifierType == "triangle_strip" &&
              isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         qualifier.primitiveType = EptTriangleStrip;
     }

     else
     {
         error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str());
     }

     return qualifier;
 }

 void TParseContext::parseLocalSize(const TString &qualifierType,
                                    const TSourceLoc &qualifierTypeLine,
                                    int intValue,
                                    const TSourceLoc &intValueLine,
                                    const std::string &intValueString,
                                    size_t index,
                                    sh::WorkGroupSize *localSize)
 {
     checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
     if (intValue < 1)
     {
         std::stringstream reasonStream;
         reasonStream << "out of range: " << getWorkGroupSizeString(index) << " must be positive";
         std::string reason = reasonStream.str();
         error(intValueLine, reason.c_str(), intValueString.c_str());
     }
     (*localSize)[index] = intValue;
 }

 void TParseContext::parseNumViews(int intValue,
                                   const TSourceLoc &intValueLine,
                                   const std::string &intValueString,
                                   int *numViews)
 {
     // This error is only specified in WebGL, but tightens unspecified behavior in the native
     // specification.
     if (intValue < 1)
     {
         error(intValueLine, "out of range: num_views must be positive", intValueString.c_str());
     }
     *numViews = intValue;
 }

 void TParseContext::parseInvocations(int intValue,
                                      const TSourceLoc &intValueLine,
                                      const std::string &intValueString,
                                      int *numInvocations)
 {
     // Although SPEC isn't clear whether invocations can be less than 1, we add this limit because
     // it doesn't make sense to accept invocations <= 0.
     if (intValue < 1 || intValue > mMaxGeometryShaderInvocations)
     {
         error(intValueLine,
               "out of range: invocations must be in the range of [1, "
               "MAX_GEOMETRY_SHADER_INVOCATIONS_OES]",
               intValueString.c_str());
     }
     else
     {
         *numInvocations = intValue;
     }
 }

 void TParseContext::parseMaxVertices(int intValue,
                                      const TSourceLoc &intValueLine,
                                      const std::string &intValueString,
                                      int *maxVertices)
 {
     // Although SPEC isn't clear whether max_vertices can be less than 0, we add this limit because
     // it doesn't make sense to accept max_vertices < 0.
     if (intValue < 0 || intValue > mMaxGeometryShaderMaxVertices)
     {
         error(
             intValueLine,
             "out of range: max_vertices must be in the range of [0, gl_MaxGeometryOutputVertices]",
             intValueString.c_str());
     }
     else
     {
         *maxVertices = intValue;
     }
 }

 TLayoutQualifier TParseContext::parseLayoutQualifier(const TString &qualifierType,
                                                      const TSourceLoc &qualifierTypeLine,
                                                      int intValue,
                                                      const TSourceLoc &intValueLine)
 {
     TLayoutQualifier qualifier = TLayoutQualifier::create();

     std::string intValueString = Str(intValue);

     if (qualifierType == "location")
     {
         // must check that location is non-negative
         if (intValue < 0)
         {
             error(intValueLine, "out of range: location must be non-negative",
                   intValueString.c_str());
         }
         else
         {
             qualifier.location           = intValue;
             qualifier.locationsSpecified = 1;
         }
     }
     else if (qualifierType == "binding")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         if (intValue < 0)
         {
             error(intValueLine, "out of range: binding must be non-negative",
                   intValueString.c_str());
         }
         else
         {
             qualifier.binding = intValue;
         }
     }
     else if (qualifierType == "offset")
     {
         checkLayoutQualifierSupported(qualifierTypeLine, qualifierType, 310);
         if (intValue < 0)
         {
             error(intValueLine, "out of range: offset must be non-negative",
                   intValueString.c_str());
         }
         else
         {
             qualifier.offset = intValue;
         }
     }
     else if (qualifierType == "local_size_x")
     {
         parseLocalSize(qualifierType, qualifierTypeLine, intValue, intValueLine, intValueString, 0u,
                        &qualifier.localSize);
     }
     else if (qualifierType == "local_size_y")
     {
         parseLocalSize(qualifierType, qualifierTypeLine, intValue, intValueLine, intValueString, 1u,
                        &qualifier.localSize);
     }
     else if (qualifierType == "local_size_z")
     {
         parseLocalSize(qualifierType, qualifierTypeLine, intValue, intValueLine, intValueString, 2u,
                        &qualifier.localSize);
     }
     else if (qualifierType == "num_views" && isExtensionEnabled(TExtension::OVR_multiview) &&
              mShaderType == GL_VERTEX_SHADER)
     {
         parseNumViews(intValue, intValueLine, intValueString, &qualifier.numViews);
     }
     else if (qualifierType == "invocations" &&
              isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         parseInvocations(intValue, intValueLine, intValueString, &qualifier.invocations);
     }
     else if (qualifierType == "max_vertices" &&
              isExtensionEnabled(TExtension::OES_geometry_shader) &&
              mShaderType == GL_GEOMETRY_SHADER_OES)
     {
         parseMaxVertices(intValue, intValueLine, intValueString, &qualifier.maxVertices);
     }

     else
     {
         error(qualifierTypeLine, "invalid layout qualifier", qualifierType.c_str());
     }

     return qualifier;
 }

 TTypeQualifierBuilder *TParseContext::createTypeQualifierBuilder(const TSourceLoc &loc)
 {
     return new TTypeQualifierBuilder(
         new TStorageQualifierWrapper(symbolTable.atGlobalLevel() ? EvqGlobal : EvqTemporary, loc),
         mShaderVersion);
 }

 TStorageQualifierWrapper *TParseContext::parseGlobalStorageQualifier(TQualifier qualifier,
                                                                      const TSourceLoc &loc)
 {
     checkIsAtGlobalLevel(loc, getQualifierString(qualifier));
     return new TStorageQualifierWrapper(qualifier, loc);
 }

 TStorageQualifierWrapper *TParseContext::parseVaryingQualifier(const TSourceLoc &loc)
 {
     if (getShaderType() == GL_VERTEX_SHADER)
     {
         return parseGlobalStorageQualifier(EvqVaryingOut, loc);
     }
     return parseGlobalStorageQualifier(EvqVaryingIn, loc);
 }

 TStorageQualifierWrapper *TParseContext::parseInQualifier(const TSourceLoc &loc)
 {
     if (declaringFunction())
     {
         return new TStorageQualifierWrapper(EvqIn, loc);
     }

     switch (getShaderType())
     {
         case GL_VERTEX_SHADER:
         {
             if (mShaderVersion < 300 && !isExtensionEnabled(TExtension::OVR_multiview))
             {
                 error(loc, "storage qualifier supported in GLSL ES 3.00 and above only", "in");
             }
             return new TStorageQualifierWrapper(EvqVertexIn, loc);
         }
         case GL_FRAGMENT_SHADER:
         {
             if (mShaderVersion < 300)
             {
                 error(loc, "storage qualifier supported in GLSL ES 3.00 and above only", "in");
             }
             return new TStorageQualifierWrapper(EvqFragmentIn, loc);
         }
         case GL_COMPUTE_SHADER:
         {
             return new TStorageQualifierWrapper(EvqComputeIn, loc);
         }
         case GL_GEOMETRY_SHADER_OES:
         {
             return new TStorageQualifierWrapper(EvqGeometryIn, loc);
         }
         default:
         {
             UNREACHABLE();
             return new TStorageQualifierWrapper(EvqLast, loc);
         }
     }
 }

 TStorageQualifierWrapper *TParseContext::parseOutQualifier(const TSourceLoc &loc)
 {
     if (declaringFunction())
     {
         return new TStorageQualifierWrapper(EvqOut, loc);
     }
     switch (getShaderType())
     {
         case GL_VERTEX_SHADER:
         {
             if (mShaderVersion < 300)
             {
                 error(loc, "storage qualifier supported in GLSL ES 3.00 and above only", "out");
             }
             return new TStorageQualifierWrapper(EvqVertexOut, loc);
         }
         case GL_FRAGMENT_SHADER:
         {
             if (mShaderVersion < 300)
             {
                 error(loc, "storage qualifier supported in GLSL ES 3.00 and above only", "out");
             }
             return new TStorageQualifierWrapper(EvqFragmentOut, loc);
         }
         case GL_COMPUTE_SHADER:
         {
             error(loc, "storage qualifier isn't supported in compute shaders", "out");
             return new TStorageQualifierWrapper(EvqLast, loc);
         }
         case GL_GEOMETRY_SHADER_OES:
         {
             return new TStorageQualifierWrapper(EvqGeometryOut, loc);
         }
         default:
         {
             UNREACHABLE();
             return new TStorageQualifierWrapper(EvqLast, loc);
         }
     }
 }

 TStorageQualifierWrapper *TParseContext::parseInOutQualifier(const TSourceLoc &loc)
 {
     if (!declaringFunction())
     {
         error(loc, "invalid qualifier: can be only used with function parameters", "inout");
     }
     return new TStorageQualifierWrapper(EvqInOut, loc);
 }

 TLayoutQualifier TParseContext::joinLayoutQualifiers(TLayoutQualifier leftQualifier,
                                                      TLayoutQualifier rightQualifier,
                                                      const TSourceLoc &rightQualifierLocation)
 {
     return sh::JoinLayoutQualifiers(leftQualifier, rightQualifier, rightQualifierLocation,
                                     mDiagnostics);
 }

 TField *TParseContext::parseStructDeclarator(TString *identifier, const TSourceLoc &loc)
 {
     checkIsNotReserved(loc, *identifier);
     TType *type = new TType(EbtVoid, EbpUndefined);
     return new TField(type, identifier, loc);
 }

 TField *TParseContext::parseStructArrayDeclarator(TString *identifier,
                                                   const TSourceLoc &loc,
                                                   unsigned int arraySize,
                                                   const TSourceLoc &arraySizeLoc)
 {
     checkIsNotReserved(loc, *identifier);

     TType *type       = new TType(EbtVoid, EbpUndefined);
     type->makeArray(arraySize);

     return new TField(type, identifier, loc);
 }

 void TParseContext::checkDoesNotHaveDuplicateFieldName(const TFieldList::const_iterator begin,
                                                        const TFieldList::const_iterator end,
                                                        const TString &name,
                                                        const TSourceLoc &location)
 {
     for (auto fieldIter = begin; fieldIter != end; ++fieldIter)
     {
         if ((*fieldIter)->name() == name)
         {
             error(location, "duplicate field name in structure", name.c_str());
         }
     }
 }

 TFieldList *TParseContext::addStructFieldList(TFieldList *fields, const TSourceLoc &location)
 {
     for (TFieldList::const_iterator fieldIter = fields->begin(); fieldIter != fields->end();
          ++fieldIter)
     {
         checkDoesNotHaveDuplicateFieldName(fields->begin(), fieldIter, (*fieldIter)->name(),
                                            location);
     }
     return fields;
 }

 TFieldList *TParseContext::combineStructFieldLists(TFieldList *processedFields,
                                                    const TFieldList *newlyAddedFields,
                                                    const TSourceLoc &location)
 {
     for (TField *field : *newlyAddedFields)
     {
         checkDoesNotHaveDuplicateFieldName(processedFields->begin(), processedFields->end(),
                                            field->name(), location);
         processedFields->push_back(field);
     }
     return processedFields;
 }

 TFieldList *TParseContext::addStructDeclaratorListWithQualifiers(
     const TTypeQualifierBuilder &typeQualifierBuilder,
     TPublicType *typeSpecifier,
     TFieldList *fieldList)
 {
     TTypeQualifier typeQualifier = typeQualifierBuilder.getVariableTypeQualifier(mDiagnostics);

     typeSpecifier->qualifier       = typeQualifier.qualifier;
     typeSpecifier->layoutQualifier = typeQualifier.layoutQualifier;
     typeSpecifier->memoryQualifier = typeQualifier.memoryQualifier;
     typeSpecifier->invariant       = typeQualifier.invariant;
     if (typeQualifier.precision != EbpUndefined)
     {
         typeSpecifier->precision = typeQualifier.precision;
     }
     return addStructDeclaratorList(*typeSpecifier, fieldList);
 }

 TFieldList *TParseContext::addStructDeclaratorList(const TPublicType &typeSpecifier,
                                                    TFieldList *declaratorList)
 {
     checkPrecisionSpecified(typeSpecifier.getLine(), typeSpecifier.precision,
                             typeSpecifier.getBasicType());

     checkIsNonVoid(typeSpecifier.getLine(), (*declaratorList)[0]->name(),
                    typeSpecifier.getBasicType());

     checkWorkGroupSizeIsNotSpecified(typeSpecifier.getLine(), typeSpecifier.layoutQualifier);

     for (TField *declarator : *declaratorList)
     {
         auto declaratorArraySizes = declarator->type()->getArraySizes();
         // don't allow arrays of arrays
         if (!declaratorArraySizes.empty())
         {
             checkArrayElementIsNotArray(typeSpecifier.getLine(), typeSpecifier);
         }

         TType *type = declarator->type();
         *type       = TType(typeSpecifier);
         for (unsigned int arraySize : declaratorArraySizes)
         {
             type->makeArray(arraySize);
         }
         checkIsNotUnsizedArray(typeSpecifier.getLine(),
                                "array members of structs must specify a size",
                                declarator->name().c_str(), type);

         checkIsBelowStructNestingLimit(typeSpecifier.getLine(), *declarator);
     }

     return declaratorList;
 }

 TTypeSpecifierNonArray TParseContext::addStructure(const TSourceLoc &structLine,
                                                    const TSourceLoc &nameLine,
                                                    const TString *structName,
                                                    TFieldList *fieldList)
 {
     TStructure *structure = new TStructure(&symbolTable, structName, fieldList);

     // Store a bool in the struct if we're at global scope, to allow us to
     // skip the local struct scoping workaround in HLSL.
     structure->setAtGlobalScope(symbolTable.atGlobalLevel());

     if (!structName->empty())
     {
         checkIsNotReserved(nameLine, *structName);
         if (!symbolTable.declareStructType(structure))
         {
             error(nameLine, "redefinition of a struct", structName->c_str());
         }
     }

     // ensure we do not specify any storage qualifiers on the struct members
     for (unsigned int typeListIndex = 0; typeListIndex < fieldList->size(); typeListIndex++)
     {
         const TField &field        = *(*fieldList)[typeListIndex];
         const TQualifier qualifier = field.type()->getQualifier();
         switch (qualifier)
         {
             case EvqGlobal:
             case EvqTemporary:
                 break;
             default:
                 error(field.line(), "invalid qualifier on struct member",
                       getQualifierString(qualifier));
                 break;
         }
         if (field.type()->isInvariant())
         {
             error(field.line(), "invalid qualifier on struct member", "invariant");
         }
         // ESSL 3.10 section 4.1.8 -- atomic_uint or images are not allowed as structure member.
         if (IsImage(field.type()->getBasicType()) || IsAtomicCounter(field.type()->getBasicType()))
         {
             error(field.line(), "disallowed type in struct", field.type()->getBasicString());
         }

         checkMemoryQualifierIsNotSpecified(field.type()->getMemoryQualifier(), field.line());

         checkBindingIsNotSpecified(field.line(), field.type()->getLayoutQualifier().binding);

         checkLocationIsNotSpecified(field.line(), field.type()->getLayoutQualifier());
     }

     TTypeSpecifierNonArray typeSpecifierNonArray;
     typeSpecifierNonArray.initializeStruct(structure, true, structLine);
     exitStructDeclaration();

     return typeSpecifierNonArray;
 }

 TIntermSwitch *TParseContext::addSwitch(TIntermTyped *init,
                                         TIntermBlock *statementList,
                                         const TSourceLoc &loc)
 {
     TBasicType switchType = init->getBasicType();
     if ((switchType != EbtInt && switchType != EbtUInt) || init->isMatrix() || init->isArray() ||
         init->isVector())
     {
         error(init->getLine(), "init-expression in a switch statement must be a scalar integer",
               "switch");
         return nullptr;
     }

     ASSERT(statementList);
     if (!ValidateSwitchStatementList(switchType, mShaderVersion, mDiagnostics, statementList, loc))
     {
         ASSERT(mDiagnostics->numErrors() > 0);
         return nullptr;
     }

     TIntermSwitch *node = new TIntermSwitch(init, statementList);
     node->setLine(loc);
     return node;
 }

 TIntermCase *TParseContext::addCase(TIntermTyped *condition, const TSourceLoc &loc)
 {
     if (mSwitchNestingLevel == 0)
     {
         error(loc, "case labels need to be inside switch statements", "case");
         return nullptr;
     }
     if (condition == nullptr)
     {
         error(loc, "case label must have a condition", "case");
         return nullptr;
     }
     if ((condition->getBasicType() != EbtInt && condition->getBasicType() != EbtUInt) ||
         condition->isMatrix() || condition->isArray() || condition->isVector())
     {
         error(condition->getLine(), "case label must be a scalar integer", "case");
     }
     TIntermConstantUnion *conditionConst = condition->getAsConstantUnion();
     // TODO(oetuaho@nvidia.com): Get rid of the conditionConst == nullptr check once all constant
     // expressions can be folded. Right now we don't allow constant expressions that ANGLE can't
     // fold in case labels.
     if (condition->getQualifier() != EvqConst || conditionConst == nullptr)
     {
         error(condition->getLine(), "case label must be constant", "case");
     }
     TIntermCase *node = new TIntermCase(condition);
     node->setLine(loc);
     return node;
 }

 TIntermCase *TParseContext::addDefault(const TSourceLoc &loc)
 {
     if (mSwitchNestingLevel == 0)
     {
         error(loc, "default labels need to be inside switch statements", "default");
         return nullptr;
     }
     TIntermCase *node = new TIntermCase(nullptr);
     node->setLine(loc);
     return node;
 }

 TIntermTyped *TParseContext::createUnaryMath(TOperator op,
                                              TIntermTyped *child,
                                              const TSourceLoc &loc)
 {
     ASSERT(child != nullptr);

     switch (op)
     {
         case EOpLogicalNot:
             if (child->getBasicType() != EbtBool || child->isMatrix() || child->isArray() ||
                 child->isVector())
             {
                 unaryOpError(loc, GetOperatorString(op), child->getCompleteString());
                 return nullptr;
             }
             break;
         case EOpBitwiseNot:
             if ((child->getBasicType() != EbtInt && child->getBasicType() != EbtUInt) ||
                 child->isMatrix() || child->isArray())
             {
                 unaryOpError(loc, GetOperatorString(op), child->getCompleteString());
                 return nullptr;
             }
             break;
         case EOpPostIncrement:
         case EOpPreIncrement:
         case EOpPostDecrement:
         case EOpPreDecrement:
         case EOpNegative:
         case EOpPositive:
             if (child->getBasicType() == EbtStruct || child->isInterfaceBlock() ||
                 child->getBasicType() == EbtBool || child->isArray() ||
                 IsOpaqueType(child->getBasicType()))
             {
                 unaryOpError(loc, GetOperatorString(op), child->getCompleteString());
                 return nullptr;
             }
         // Operators for built-ins are already type checked against their prototype.
         default:
             break;
     }

     if (child->getMemoryQualifier().writeonly)
     {
         unaryOpError(loc, GetOperatorString(op), child->getCompleteString());
         return nullptr;
     }

     TIntermUnary *node = new TIntermUnary(op, child);
     node->setLine(loc);

     return node->fold(mDiagnostics);
 }

 TIntermTyped *TParseContext::addUnaryMath(TOperator op, TIntermTyped *child, const TSourceLoc &loc)
 {
     ASSERT(op != EOpNull);
     TIntermTyped *node = createUnaryMath(op, child, loc);
     if (node == nullptr)
     {
         return child;
     }
     return node;
 }

 TIntermTyped *TParseContext::addUnaryMathLValue(TOperator op,
                                                 TIntermTyped *child,
                                                 const TSourceLoc &loc)
 {
     checkCanBeLValue(loc, GetOperatorString(op), child);
     return addUnaryMath(op, child, loc);
 }

 bool TParseContext::binaryOpCommonCheck(TOperator op,
                                         TIntermTyped *left,
                                         TIntermTyped *right,
                                         const TSourceLoc &loc)
 {
     // Check opaque types are not allowed to be operands in expressions other than array indexing
     // and structure member selection.
     if (IsOpaqueType(left->getBasicType()) || IsOpaqueType(right->getBasicType()))
     {
         switch (op)
         {
             case EOpIndexDirect:
             case EOpIndexIndirect:
                 break;
             case EOpIndexDirectStruct:
                 UNREACHABLE();

             default:
                 error(loc, "Invalid operation for variables with an opaque type",
                       GetOperatorString(op));
                 return false;
         }
     }

     if (right->getMemoryQualifier().writeonly)
     {
         error(loc, "Invalid operation for variables with writeonly", GetOperatorString(op));
         return false;
     }

     if (left->getMemoryQualifier().writeonly)
     {
         switch (op)
         {
             case EOpAssign:
             case EOpInitialize:
             case EOpIndexDirect:
             case EOpIndexIndirect:
             case EOpIndexDirectStruct:
             case EOpIndexDirectInterfaceBlock:
                 break;
             default:
                 error(loc, "Invalid operation for variables with writeonly", GetOperatorString(op));
                 return false;
         }
     }

     if (left->getType().getStruct() || right->getType().getStruct())
     {
         switch (op)
         {
             case EOpIndexDirectStruct:
                 ASSERT(left->getType().getStruct());
                 break;
             case EOpEqual:
             case EOpNotEqual:
             case EOpAssign:
             case EOpInitialize:
                 if (left->getType() != right->getType())
                 {
                     return false;
                 }
                 break;
             default:
                 error(loc, "Invalid operation for structs", GetOperatorString(op));
                 return false;
         }
     }

     if (left->isInterfaceBlock() || right->isInterfaceBlock())
     {
         switch (op)
         {
             case EOpIndexDirectInterfaceBlock:
                 ASSERT(left->getType().getInterfaceBlock());
                 break;
             default:
                 error(loc, "Invalid operation for interface blocks", GetOperatorString(op));
                 return false;
         }
     }

     if (left->isArray() || right->isArray())
     {
         if (mShaderVersion < 300)
         {
             error(loc, "Invalid operation for arrays", GetOperatorString(op));
             return false;
         }

         if (left->isArray() != right->isArray())
         {
             error(loc, "array / non-array mismatch", GetOperatorString(op));
             return false;
         }

         switch (op)
         {
             case EOpEqual:
             case EOpNotEqual:
             case EOpAssign:
             case EOpInitialize:
                 break;
             default:
                 error(loc, "Invalid operation for arrays", GetOperatorString(op));
                 return false;
         }
         // At this point, size of implicitly sized arrays should be resolved.
         if (left->getType().getArraySizes() != right->getType().getArraySizes())
         {
             error(loc, "array size mismatch", GetOperatorString(op));
             return false;
         }
     }

     // Check ops which require integer / ivec parameters
     bool isBitShift = false;
     switch (op)
     {
         case EOpBitShiftLeft:
         case EOpBitShiftRight:
         case EOpBitShiftLeftAssign:
         case EOpBitShiftRightAssign:
             // Unsigned can be bit-shifted by signed and vice versa, but we need to
             // check that the basic type is an integer type.
             isBitShift = true;
             if (!IsInteger(left->getBasicType()) || !IsInteger(right->getBasicType()))
             {
                 return false;
             }
             break;
         case EOpBitwiseAnd:
         case EOpBitwiseXor:
         case EOpBitwiseOr:
         case EOpBitwiseAndAssign:
         case EOpBitwiseXorAssign:
         case EOpBitwiseOrAssign:
             // It is enough to check the type of only one operand, since later it
             // is checked that the operand types match.
             if (!IsInteger(left->getBasicType()))
             {
                 return false;
             }
             break;
         default:
             break;
     }

     // GLSL ES 1.00 and 3.00 do not support implicit type casting.
     // So the basic type should usually match.
     if (!isBitShift && left->getBasicType() != right->getBasicType())
     {
         return false;
     }

     // Check that:
     // 1. Type sizes match exactly on ops that require that.
     // 2. Restrictions for structs that contain arrays or samplers are respected.
     // 3. Arithmetic op type dimensionality restrictions for ops other than multiply are respected.
     switch (op)
     {
         case EOpAssign:
         case EOpInitialize:
         case EOpEqual:
         case EOpNotEqual:
             // ESSL 1.00 sections 5.7, 5.8, 5.9
             if (mShaderVersion < 300 && left->getType().isStructureContainingArrays())
             {
                 error(loc, "undefined operation for structs containing arrays",
                       GetOperatorString(op));
                 return false;
             }
             // Samplers as l-values are disallowed also in ESSL 3.00, see section 4.1.7,
             // we interpret the spec so that this extends to structs containing samplers,
             // similarly to ESSL 1.00 spec.
             if ((mShaderVersion < 300 || op == EOpAssign || op == EOpInitialize) &&
                 left->getType().isStructureContainingSamplers())
             {
                 error(loc, "undefined operation for structs containing samplers",
                       GetOperatorString(op));
                 return false;
             }

             if ((left->getNominalSize() != right->getNominalSize()) ||
                 (left->getSecondarySize() != right->getSecondarySize()))
             {
                 error(loc, "dimension mismatch", GetOperatorString(op));
                 return false;
             }
             break;
         case EOpLessThan:
         case EOpGreaterThan:
         case EOpLessThanEqual:
         case EOpGreaterThanEqual:
             if (!left->isScalar() || !right->isScalar())
             {
                 error(loc, "comparison operator only defined for scalars", GetOperatorString(op));
                 return false;
             }
             break;
         case EOpAdd:
         case EOpSub:
         case EOpDiv:
         case EOpIMod:
         case EOpBitShiftLeft:
         case EOpBitShiftRight:
         case EOpBitwiseAnd:
         case EOpBitwiseXor:
         case EOpBitwiseOr:
         case EOpAddAssign:
         case EOpSubAssign:
         case EOpDivAssign:
         case EOpIModAssign:
         case EOpBitShiftLeftAssign:
         case EOpBitShiftRightAssign:
         case EOpBitwiseAndAssign:
         case EOpBitwiseXorAssign:
         case EOpBitwiseOrAssign:
             if ((left->isMatrix() && right->isVector()) || (left->isVector() && right->isMatrix()))
             {
                 return false;
             }

             // Are the sizes compatible?
             if (left->getNominalSize() != right->getNominalSize() ||
                 left->getSecondarySize() != right->getSecondarySize())
             {
                 // If the nominal sizes of operands do not match:
                 // One of them must be a scalar.
                 if (!left->isScalar() && !right->isScalar())
                     return false;

                 // In the case of compound assignment other than multiply-assign,
                 // the right side needs to be a scalar. Otherwise a vector/matrix
                 // would be assigned to a scalar. A scalar can't be shifted by a
                 // vector either.
                 if (!right->isScalar() &&
                     (IsAssignment(op) || op == EOpBitShiftLeft || op == EOpBitShiftRight))
                     return false;
             }
             break;
         default:
             break;
     }

     return true;
 }

 bool TParseContext::isMultiplicationTypeCombinationValid(TOperator op,
                                                          const TType &left,
                                                          const TType &right)
 {
     switch (op)
     {
         case EOpMul:
         case EOpMulAssign:
             return left.getNominalSize() == right.getNominalSize() &&
                    left.getSecondarySize() == right.getSecondarySize();
         case EOpVectorTimesScalar:
             return true;
         case EOpVectorTimesScalarAssign:
             ASSERT(!left.isMatrix() && !right.isMatrix());
             return left.isVector() && !right.isVector();
         case EOpVectorTimesMatrix:
             return left.getNominalSize() == right.getRows();
         case EOpVectorTimesMatrixAssign:
             ASSERT(!left.isMatrix() && right.isMatrix());
             return left.isVector() && left.getNominalSize() == right.getRows() &&
                    left.getNominalSize() == right.getCols();
         case EOpMatrixTimesVector:
             return left.getCols() == right.getNominalSize();
         case EOpMatrixTimesScalar:
             return true;
         case EOpMatrixTimesScalarAssign:
             ASSERT(left.isMatrix() && !right.isMatrix());
             return !right.isVector();
         case EOpMatrixTimesMatrix:
             return left.getCols() == right.getRows();
         case EOpMatrixTimesMatrixAssign:
             ASSERT(left.isMatrix() && right.isMatrix());
             // We need to check two things:
             // 1. The matrix multiplication step is valid.
             // 2. The result will have the same number of columns as the lvalue.
             return left.getCols() == right.getRows() && left.getCols() == right.getCols();

         default:
             UNREACHABLE();
             return false;
     }
 }

 TIntermTyped *TParseContext::addBinaryMathInternal(TOperator op,
                                                    TIntermTyped *left,
                                                    TIntermTyped *right,
                                                    const TSourceLoc &loc)
 {
     if (!binaryOpCommonCheck(op, left, right, loc))
         return nullptr;

     switch (op)
     {
         case EOpEqual:
         case EOpNotEqual:
         case EOpLessThan:
         case EOpGreaterThan:
         case EOpLessThanEqual:
         case EOpGreaterThanEqual:
             break;
         case EOpLogicalOr:
         case EOpLogicalXor:
         case EOpLogicalAnd:
             ASSERT(!left->isArray() && !right->isArray() && !left->getType().getStruct() &&
                    !right->getType().getStruct());
             if (left->getBasicType() != EbtBool || !left->isScalar() || !right->isScalar())
             {
                 return nullptr;
             }
             // Basic types matching should have been already checked.
             ASSERT(right->getBasicType() == EbtBool);
             break;
         case EOpAdd:
         case EOpSub:
         case EOpDiv:
         case EOpMul:
             ASSERT(!left->isArray() && !right->isArray() && !left->getType().getStruct() &&
                    !right->getType().getStruct());
             if (left->getBasicType() == EbtBool)
             {
                 return nullptr;
             }
             break;
         case EOpIMod:
             ASSERT(!left->isArray() && !right->isArray() && !left->getType().getStruct() &&
                    !right->getType().getStruct());
             // Note that this is only for the % operator, not for mod()
             if (left->getBasicType() == EbtBool || left->getBasicType() == EbtFloat)
             {
                 return nullptr;
             }
             break;
         default:
             break;
     }

     if (op == EOpMul)
     {
         op = TIntermBinary::GetMulOpBasedOnOperands(left->getType(), right->getType());
         if (!isMultiplicationTypeCombinationValid(op, left->getType(), right->getType()))
         {
             return nullptr;
         }
     }

     TIntermBinary *node = new TIntermBinary(op, left, right);
     node->setLine(loc);

     // See if we can fold constants.
     return node->fold(mDiagnostics);
 }

 TIntermTyped *TParseContext::addBinaryMath(TOperator op,
                                            TIntermTyped *left,
                                            TIntermTyped *right,
                                            const TSourceLoc &loc)
 {
     TIntermTyped *node = addBinaryMathInternal(op, left, right, loc);
     if (node == 0)
     {
         binaryOpError(loc, GetOperatorString(op), left->getCompleteString(),
                       right->getCompleteString());
         return left;
     }
     return node;
 }

 TIntermTyped *TParseContext::addBinaryMathBooleanResult(TOperator op,
                                                         TIntermTyped *left,
                                                         TIntermTyped *right,
                                                         const TSourceLoc &loc)
 {
     TIntermTyped *node = addBinaryMathInternal(op, left, right, loc);
     if (node == nullptr)
     {
         binaryOpError(loc, GetOperatorString(op), left->getCompleteString(),
                       right->getCompleteString());
         node = CreateBoolNode(false);
         node->setLine(loc);
     }
     return node;
 }

 TIntermBinary *TParseContext::createAssign(TOperator op,
                                            TIntermTyped *left,
                                            TIntermTyped *right,
                                            const TSourceLoc &loc)
 {
     if (binaryOpCommonCheck(op, left, right, loc))
     {
         if (op == EOpMulAssign)
         {
             op = TIntermBinary::GetMulAssignOpBasedOnOperands(left->getType(), right->getType());
             if (!isMultiplicationTypeCombinationValid(op, left->getType(), right->getType()))
             {
                 return nullptr;
             }
         }
         TIntermBinary *node = new TIntermBinary(op, left, right);
         node->setLine(loc);

         return node;
     }
     return nullptr;
 }

 TIntermTyped *TParseContext::addAssign(TOperator op,
                                        TIntermTyped *left,
                                        TIntermTyped *right,
                                        const TSourceLoc &loc)
 {
     checkCanBeLValue(loc, "assign", left);
     TIntermTyped *node = createAssign(op, left, right, loc);
     if (node == nullptr)
     {
         assignError(loc, "assign", left->getCompleteString(), right->getCompleteString());
         return left;
     }
     return node;
 }

 TIntermTyped *TParseContext::addComma(TIntermTyped *left,
                                       TIntermTyped *right,
                                       const TSourceLoc &loc)
 {
     // WebGL2 section 5.26, the following results in an error:
     // "Sequence operator applied to void, arrays, or structs containing arrays"
     if (mShaderSpec == SH_WEBGL2_SPEC &&
         (left->isArray() || left->getBasicType() == EbtVoid ||
          left->getType().isStructureContainingArrays() || right->isArray() ||
          right->getBasicType() == EbtVoid || right->getType().isStructureContainingArrays()))
     {
         error(loc,
               "sequence operator is not allowed for void, arrays, or structs containing arrays",
               ",");
     }

     TIntermBinary *commaNode   = new TIntermBinary(EOpComma, left, right);
     TQualifier resultQualifier = TIntermBinary::GetCommaQualifier(mShaderVersion, left, right);
     commaNode->getTypePointer()->setQualifier(resultQualifier);
     return commaNode->fold(mDiagnostics);
 }

 TIntermBranch *TParseContext::addBranch(TOperator op, const TSourceLoc &loc)
 {
     switch (op)
     {
         case EOpContinue:
             if (mLoopNestingLevel <= 0)
             {
                 error(loc, "continue statement only allowed in loops", "");
             }
             break;
         case EOpBreak:
             if (mLoopNestingLevel <= 0 && mSwitchNestingLevel <= 0)
             {
                 error(loc, "break statement only allowed in loops and switch statements", "");
             }
             break;
         case EOpReturn:
             if (mCurrentFunctionType->getBasicType() != EbtVoid)
             {
                 error(loc, "non-void function must return a value", "return");
             }
             break;
         case EOpKill:
             if (mShaderType != GL_FRAGMENT_SHADER)
             {
                 error(loc, "discard supported in fragment shaders only", "discard");
             }
             break;
         default:
             UNREACHABLE();
             break;
     }
     return addBranch(op, nullptr, loc);
 }

 TIntermBranch *TParseContext::addBranch(TOperator op,
                                         TIntermTyped *expression,
                                         const TSourceLoc &loc)
 {
     if (expression != nullptr)
     {
         ASSERT(op == EOpReturn);
         mFunctionReturnsValue = true;
         if (mCurrentFunctionType->getBasicType() == EbtVoid)
         {
             error(loc, "void function cannot return a value", "return");
         }
         else if (*mCurrentFunctionType != expression->getType())
         {
             error(loc, "function return is not matching type:", "return");
         }
     }
     TIntermBranch *node = new TIntermBranch(op, expression);
     node->setLine(loc);
     return node;
 }

 void TParseContext::checkTextureGather(TIntermAggregate *functionCall)
 {
     ASSERT(functionCall->getOp() == EOpCallBuiltInFunction);
     const TString &name        = functionCall->getFunctionSymbolInfo()->getName();
     bool isTextureGather       = (name == "textureGather");
     bool isTextureGatherOffset = (name == "textureGatherOffset");
     if (isTextureGather || isTextureGatherOffset)
     {
         TIntermNode *componentNode = nullptr;
         TIntermSequence *arguments = functionCall->getSequence();
         ASSERT(arguments->size() >= 2u && arguments->size() <= 4u);
         const TIntermTyped *sampler = arguments->front()->getAsTyped();
         ASSERT(sampler != nullptr);
         switch (sampler->getBasicType())
         {
             case EbtSampler2D:
             case EbtISampler2D:
             case EbtUSampler2D:
             case EbtSampler2DArray:
             case EbtISampler2DArray:
             case EbtUSampler2DArray:
                 if ((isTextureGather && arguments->size() == 3u) ||
                     (isTextureGatherOffset && arguments->size() == 4u))
                 {
                     componentNode = arguments->back();
                 }
                 break;
             case EbtSamplerCube:
             case EbtISamplerCube:
             case EbtUSamplerCube:
                 ASSERT(!isTextureGatherOffset);
                 if (arguments->size() == 3u)
                 {
                     componentNode = arguments->back();
                 }
                 break;
             case EbtSampler2DShadow:
             case EbtSampler2DArrayShadow:
             case EbtSamplerCubeShadow:
                 break;
             default:
                 UNREACHABLE();
                 break;
         }
         if (componentNode)
         {
             const TIntermConstantUnion *componentConstantUnion =
                 componentNode->getAsConstantUnion();
             if (componentNode->getAsTyped()->getQualifier() != EvqConst || !componentConstantUnion)
             {
                 error(functionCall->getLine(), "Texture component must be a constant expression",
                       name.c_str());
             }
             else
             {
                 int component = componentConstantUnion->getIConst(0);
                 if (component < 0 || component > 3)
                 {
                     error(functionCall->getLine(), "Component must be in the range [0;3]",
                           name.c_str());
                 }
             }
         }
     }
 }

 void TParseContext::checkTextureOffsetConst(TIntermAggregate *functionCall)
 {
     ASSERT(functionCall->getOp() == EOpCallBuiltInFunction);
     const TString &name        = functionCall->getFunctionSymbolInfo()->getName();
     TIntermNode *offset        = nullptr;
     TIntermSequence *arguments = functionCall->getSequence();
     bool useTextureGatherOffsetConstraints = false;
     if (name == "texelFetchOffset" || name == "textureLodOffset" ||
         name == "textureProjLodOffset" || name == "textureGradOffset" ||
         name == "textureProjGradOffset")
     {
         offset = arguments->back();
     }
     else if (name == "textureOffset" || name == "textureProjOffset")
     {
         // A bias parameter might follow the offset parameter.
         ASSERT(arguments->size() >= 3);
         offset = (*arguments)[2];
     }
     else if (name == "textureGatherOffset")
     {
         ASSERT(arguments->size() >= 3u);
         const TIntermTyped *sampler = arguments->front()->getAsTyped();
         ASSERT(sampler != nullptr);
         switch (sampler->getBasicType())
         {
             case EbtSampler2D:
             case EbtISampler2D:
             case EbtUSampler2D:
             case EbtSampler2DArray:
             case EbtISampler2DArray:
             case EbtUSampler2DArray:
                 offset = (*arguments)[2];
                 break;
             case EbtSampler2DShadow:
             case EbtSampler2DArrayShadow:
                 offset = (*arguments)[3];
                 break;
             default:
                 UNREACHABLE();
                 break;
         }
         useTextureGatherOffsetConstraints = true;
     }
     if (offset != nullptr)
     {
         TIntermConstantUnion *offsetConstantUnion = offset->getAsConstantUnion();
         if (offset->getAsTyped()->getQualifier() != EvqConst || !offsetConstantUnion)
         {
             error(functionCall->getLine(), "Texture offset must be a constant expression",
                   name.c_str());
         }
         else
         {
             ASSERT(offsetConstantUnion->getBasicType() == EbtInt);
             size_t size                  = offsetConstantUnion->getType().getObjectSize();
             const TConstantUnion *values = offsetConstantUnion->getUnionArrayPointer();
             int minOffsetValue = useTextureGatherOffsetConstraints ? mMinProgramTextureGatherOffset
                                                                    : mMinProgramTexelOffset;
             int maxOffsetValue = useTextureGatherOffsetConstraints ? mMaxProgramTextureGatherOffset
                                                                    : mMaxProgramTexelOffset;
             for (size_t i = 0u; i < size; ++i)
             {
                 int offsetValue = values[i].getIConst();
                 if (offsetValue > maxOffsetValue || offsetValue < minOffsetValue)
                 {
                     std::stringstream tokenStream;
                     tokenStream << offsetValue;
                     std::string token = tokenStream.str();
                     error(offset->getLine(), "Texture offset value out of valid range",
                           token.c_str());
                 }
             }
         }
     }
 }

 // GLSL ES 3.10 Revision 4, 4.9 Memory Access Qualifiers
 void TParseContext::checkImageMemoryAccessForBuiltinFunctions(TIntermAggregate *functionCall)
 {
     ASSERT(functionCall->getOp() == EOpCallBuiltInFunction);
     const TString &name = functionCall->getFunctionSymbolInfo()->getName();

     if (name.compare(0, 5, "image") == 0)
     {
         TIntermSequence *arguments = functionCall->getSequence();
         TIntermTyped *imageNode    = (*arguments)[0]->getAsTyped();

         const TMemoryQualifier &memoryQualifier = imageNode->getMemoryQualifier();

         if (name.compare(5, 5, "Store") == 0)
         {
             if (memoryQualifier.readonly)
             {
                 error(imageNode->getLine(),
                       "'imageStore' cannot be used with images qualified as 'readonly'",
                       GetImageArgumentToken(imageNode));
             }
         }
         else if (name.compare(5, 4, "Load") == 0)
         {
             if (memoryQualifier.writeonly)
             {
                 error(imageNode->getLine(),
                       "'imageLoad' cannot be used with images qualified as 'writeonly'",
                       GetImageArgumentToken(imageNode));
             }
         }
     }
 }

 // GLSL ES 3.10 Revision 4, 13.51 Matching of Memory Qualifiers in Function Parameters
 void TParseContext::checkImageMemoryAccessForUserDefinedFunctions(
     const TFunction *functionDefinition,
     const TIntermAggregate *functionCall)
 {
     ASSERT(functionCall->getOp() == EOpCallFunctionInAST);

     const TIntermSequence &arguments = *functionCall->getSequence();

     ASSERT(functionDefinition->getParamCount() == arguments.size());

     for (size_t i = 0; i < arguments.size(); ++i)
     {
         TIntermTyped *typedArgument        = arguments[i]->getAsTyped();
         const TType &functionArgumentType  = typedArgument->getType();
         const TType &functionParameterType = *functionDefinition->getParam(i).type;
         ASSERT(functionArgumentType.getBasicType() == functionParameterType.getBasicType());

         if (IsImage(functionArgumentType.getBasicType()))
         {
             const TMemoryQualifier &functionArgumentMemoryQualifier =
                 functionArgumentType.getMemoryQualifier();
             const TMemoryQualifier &functionParameterMemoryQualifier =
                 functionParameterType.getMemoryQualifier();
             if (functionArgumentMemoryQualifier.readonly &&
                 !functionParameterMemoryQualifier.readonly)
             {
                 error(functionCall->getLine(),
                       "Function call discards the 'readonly' qualifier from image",
                       GetImageArgumentToken(typedArgument));
             }

             if (functionArgumentMemoryQualifier.writeonly &&
                 !functionParameterMemoryQualifier.writeonly)
             {
                 error(functionCall->getLine(),
                       "Function call discards the 'writeonly' qualifier from image",
                       GetImageArgumentToken(typedArgument));
             }

             if (functionArgumentMemoryQualifier.coherent &&
                 !functionParameterMemoryQualifier.coherent)
             {
                 error(functionCall->getLine(),
                       "Function call discards the 'coherent' qualifier from image",
                       GetImageArgumentToken(typedArgument));
             }

             if (functionArgumentMemoryQualifier.volatileQualifier &&
                 !functionParameterMemoryQualifier.volatileQualifier)
             {
                 error(functionCall->getLine(),
                       "Function call discards the 'volatile' qualifier from image",
                       GetImageArgumentToken(typedArgument));
             }
         }
     }
 }

 TIntermSequence *TParseContext::createEmptyArgumentsList()
 {
     return new TIntermSequence();
 }

 TIntermTyped *TParseContext::addFunctionCallOrMethod(TFunction *fnCall,
                                                      TIntermSequence *arguments,
                                                      TIntermNode *thisNode,
                                                      const TSourceLoc &loc)
 {
     if (thisNode != nullptr)
     {
         return addMethod(fnCall, arguments, thisNode, loc);
     }

     TOperator op = fnCall->getBuiltInOp();
     if (op == EOpConstruct)
     {
         return addConstructor(arguments, fnCall->getReturnType(), loc);
     }
     else
     {
         ASSERT(op == EOpNull);
         return addNonConstructorFunctionCall(fnCall, arguments, loc);
     }
 }

 TIntermTyped *TParseContext::addMethod(TFunction *fnCall,
                                        TIntermSequence *arguments,
                                        TIntermNode *thisNode,
                                        const TSourceLoc &loc)
 {
     TIntermTyped *typedThis    = thisNode->getAsTyped();
     // It's possible for the name pointer in the TFunction to be null in case it gets parsed as
     // a constructor. But such a TFunction can't reach here, since the lexer goes into FIELDS
     // mode after a dot, which makes type identifiers to be parsed as FIELD_SELECTION instead.
     // So accessing fnCall->getName() below is safe.
     if (fnCall->getName() != "length")
     {
         error(loc, "invalid method", fnCall->getName().c_str());
     }
     else if (!arguments->empty())
     {
         error(loc, "method takes no parameters", "length");
     }
     else if (typedThis == nullptr || !typedThis->isArray())
     {
         error(loc, "length can only be called on arrays", "length");
     }
     else if (typedThis->getQualifier() == EvqPerVertexIn &&
              mGeometryShaderInputPrimitiveType == EptUndefined)
     {
         ASSERT(mShaderType == GL_GEOMETRY_SHADER_OES);
         error(loc, "missing input primitive declaration before calling length on gl_in", "length");
     }
     else
     {
         TIntermUnary *node = new TIntermUnary(EOpArrayLength, typedThis);
         node->setLine(loc);
         return node->fold(mDiagnostics);
     }
     return CreateZeroNode(TType(EbtInt, EbpUndefined, EvqConst));
 }

 TIntermTyped *TParseContext::addNonConstructorFunctionCall(TFunction *fnCall,
                                                            TIntermSequence *arguments,
                                                            const TSourceLoc &loc)
 {
     // First find by unmangled name to check whether the function name has been
     // hidden by a variable name or struct typename.
     // If a function is found, check for one with a matching argument list.
     bool builtIn;
     const TSymbol *symbol = symbolTable.find(fnCall->getName(), mShaderVersion, &builtIn);
     if (symbol != nullptr && !symbol->isFunction())
     {
         error(loc, "function name expected", fnCall->getName().c_str());
     }
     else
     {
         symbol = symbolTable.find(TFunction::GetMangledNameFromCall(fnCall->getName(), *arguments),
                                   mShaderVersion, &builtIn);
         if (symbol == nullptr)
         {
             error(loc, "no matching overloaded function found", fnCall->getName().c_str());
         }
         else
         {
             const TFunction *fnCandidate = static_cast<const TFunction *>(symbol);
             //
             // A declared function.
             //
             if (builtIn && fnCandidate->getExtension() != TExtension::UNDEFINED)
             {
                 checkCanUseExtension(loc, fnCandidate->getExtension());
             }
             TOperator op = fnCandidate->getBuiltInOp();
             if (builtIn && op != EOpNull)
             {
                 // A function call mapped to a built-in operation.
                 if (fnCandidate->getParamCount() == 1)
                 {
                     // Treat it like a built-in unary operator.
                     TIntermNode *unaryParamNode = arguments->front();
                     TIntermTyped *callNode = createUnaryMath(op, unaryParamNode->getAsTyped(), loc);
                     ASSERT(callNode != nullptr);
                     return callNode;
                 }
                 else
                 {
                     TIntermAggregate *callNode =
                         TIntermAggregate::Create(fnCandidate->getReturnType(), op, arguments);
                     callNode->setLine(loc);

                     // Some built-in functions have out parameters too.
                     functionCallRValueLValueErrorCheck(fnCandidate, callNode);

                     if (TIntermAggregate::CanFoldAggregateBuiltInOp(callNode->getOp()))
                     {
                         // See if we can constant fold a built-in. Note that this may be possible
                         // even if it is not const-qualified.
                         return callNode->fold(mDiagnostics);
                     }
                     else
                     {
                         return callNode;
                     }
                 }
             }
             else
             {
                 // This is a real function call
                 TIntermAggregate *callNode = nullptr;

                 // If builtIn == false, the function is user defined - could be an overloaded
                 // built-in as well.
                 // if builtIn == true, it's a builtIn function with no op associated with it.
                 // This needs to happen after the function info including name is set.
                 if (builtIn)
                 {
                     callNode = TIntermAggregate::CreateBuiltInFunctionCall(*fnCandidate, arguments);
                     checkTextureOffsetConst(callNode);
                     checkTextureGather(callNode);
                     checkImageMemoryAccessForBuiltinFunctions(callNode);
                 }
                 else
                 {
                     callNode = TIntermAggregate::CreateFunctionCall(*fnCandidate, arguments);
                     checkImageMemoryAccessForUserDefinedFunctions(fnCandidate, callNode);
                 }

                 functionCallRValueLValueErrorCheck(fnCandidate, callNode);

                 callNode->setLine(loc);

                 return callNode;
             }
         }
     }

     // Error message was already written. Put on a dummy node for error recovery.
     return CreateZeroNode(TType(EbtFloat, EbpMedium, EvqConst));
 }

 TIntermTyped *TParseContext::addTernarySelection(TIntermTyped *cond,
                                                  TIntermTyped *trueExpression,
                                                  TIntermTyped *falseExpression,
                                                  const TSourceLoc &loc)
 {
     if (!checkIsScalarBool(loc, cond))
     {
         return falseExpression;
     }

     if (trueExpression->getType() != falseExpression->getType())
     {
         std::stringstream reasonStream;
         reasonStream << "mismatching ternary operator operand types '"
                      << trueExpression->getCompleteString() << " and '"
                      << falseExpression->getCompleteString() << "'";
         std::string reason = reasonStream.str();
         error(loc, reason.c_str(), "?:");
         return falseExpression;
     }
     if (IsOpaqueType(trueExpression->getBasicType()))
     {
         // ESSL 1.00 section 4.1.7
         // ESSL 3.00.6 section 4.1.7
         // Opaque/sampler types are not allowed in most types of expressions, including ternary.
         // Note that structs containing opaque types don't need to be checked as structs are
         // forbidden below.
         error(loc, "ternary operator is not allowed for opaque types", "?:");
         return falseExpression;
     }

     if (cond->getMemoryQualifier().writeonly || trueExpression->getMemoryQualifier().writeonly ||
         falseExpression->getMemoryQualifier().writeonly)
     {
         error(loc, "ternary operator is not allowed for variables with writeonly", "?:");
         return falseExpression;
     }

     // ESSL 1.00.17 sections 5.2 and 5.7:
     // Ternary operator is not among the operators allowed for structures/arrays.
     // ESSL 3.00.6 section 5.7:
     // Ternary operator support is optional for arrays. No certainty that it works across all
     // devices with struct either, so we err on the side of caution here. TODO (oetuaho@nvidia.com):
     // Would be nice to make the spec and implementation agree completely here.
     if (trueExpression->isArray() || trueExpression->getBasicType() == EbtStruct)
     {
         error(loc, "ternary operator is not allowed for structures or arrays", "?:");
         return falseExpression;
     }
     if (trueExpression->getBasicType() == EbtInterfaceBlock)
     {
         error(loc, "ternary operator is not allowed for interface blocks", "?:");
         return falseExpression;
     }

     // WebGL2 section 5.26, the following results in an error:
     // "Ternary operator applied to void, arrays, or structs containing arrays"
     if (mShaderSpec == SH_WEBGL2_SPEC && trueExpression->getBasicType() == EbtVoid)
     {
         error(loc, "ternary operator is not allowed for void", "?:");
         return falseExpression;
     }

     // Note that the node resulting from here can be a constant union without being qualified as
     // constant.
     TIntermTernary *node = new TIntermTernary(cond, trueExpression, falseExpression);
     node->setLine(loc);

     return node->fold();
 }

 //
 // Parse an array of strings using yyparse.
 //
 // Returns 0 for success.
 //
 int PaParseStrings(size_t count,
                    const char *const string[],
                    const int length[],
                    TParseContext *context)
 {
     if ((count == 0) || (string == nullptr))
         return 1;

     if (glslang_initialize(context))
         return 1;

     int error = glslang_scan(count, string, length, context);
     if (!error)
         error = glslang_parse(context);

     glslang_finalize(context);

     return (error == 0) && (context->numErrors() == 0) ? 0 : 1;
 }

 }  // namespace sh