| /* |
| * Copyright 2016 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SKSL_VARIABLEREFERENCE |
| #define SKSL_VARIABLEREFERENCE |
| |
| #include "SkSLExpression.h" |
| #include "SkSLFloatLiteral.h" |
| #include "SkSLIRGenerator.h" |
| #include "SkSLIntLiteral.h" |
| |
| namespace SkSL { |
| |
| /** |
| * A reference to a variable, through which it can be read or written. In the statement: |
| * |
| * x = x + 1; |
| * |
| * there is only one Variable 'x', but two VariableReferences to it. |
| */ |
| struct VariableReference : public Expression { |
| enum RefKind { |
| kRead_RefKind, |
| kWrite_RefKind, |
| kReadWrite_RefKind |
| }; |
| |
| VariableReference(Position position, const Variable& variable, RefKind refKind = kRead_RefKind) |
| : INHERITED(position, kVariableReference_Kind, variable.fType) |
| , fVariable(variable) |
| , fRefKind(refKind) { |
| if (refKind != kRead_RefKind) { |
| fVariable.fWriteCount++; |
| } |
| if (refKind != kWrite_RefKind) { |
| fVariable.fReadCount++; |
| } |
| } |
| |
| virtual ~VariableReference() override { |
| if (fRefKind != kWrite_RefKind) { |
| fVariable.fReadCount--; |
| } |
| } |
| |
| RefKind refKind() { |
| return fRefKind; |
| } |
| |
| void setRefKind(RefKind refKind) { |
| if (fRefKind != kRead_RefKind) { |
| fVariable.fWriteCount--; |
| } |
| if (fRefKind != kWrite_RefKind) { |
| fVariable.fReadCount--; |
| } |
| if (refKind != kRead_RefKind) { |
| fVariable.fWriteCount++; |
| } |
| if (refKind != kWrite_RefKind) { |
| fVariable.fReadCount++; |
| } |
| fRefKind = refKind; |
| } |
| |
| SkString description() const override { |
| return fVariable.fName; |
| } |
| |
| virtual std::unique_ptr<Expression> constantPropagate( |
| const IRGenerator& irGenerator, |
| const DefinitionMap& definitions) override { |
| auto exprIter = definitions.find(&fVariable); |
| if (exprIter != definitions.end() && exprIter->second) { |
| const Expression* expr = exprIter->second->get(); |
| switch (expr->fKind) { |
| case Expression::kIntLiteral_Kind: |
| return std::unique_ptr<Expression>(new IntLiteral( |
| irGenerator.fContext, |
| Position(), |
| ((IntLiteral*) expr)->fValue)); |
| case Expression::kFloatLiteral_Kind: |
| return std::unique_ptr<Expression>(new FloatLiteral( |
| irGenerator.fContext, |
| Position(), |
| ((FloatLiteral*) expr)->fValue)); |
| default: |
| break; |
| } |
| } |
| return nullptr; |
| } |
| |
| const Variable& fVariable; |
| |
| private: |
| RefKind fRefKind; |
| |
| typedef Expression INHERITED; |
| }; |
| |
| } // namespace |
| |
| #endif |