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//===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file implements the actions class which performs semantic analysis and
// builds an AST out of a parse stream.
#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTDiagnostic.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclFriend.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/CXXFieldCollector.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/ExternalSemaSource.h"
#include "clang/Sema/MultiplexExternalSemaSource.h"
#include "clang/Sema/ObjCMethodList.h"
#include "clang/Sema/PrettyDeclStackTrace.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaConsumer.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/Support/CrashRecoveryContext.h"
using namespace clang;
using namespace sema;
PrintingPolicy Sema::getPrintingPolicy(const ASTContext &Context,
const Preprocessor &PP) {
PrintingPolicy Policy = Context.getPrintingPolicy();
Policy.Bool = Context.getLangOpts().Bool;
if (!Policy.Bool) {
if (const MacroInfo *
BoolMacro = PP.getMacroInfo(&Context.Idents.get("bool"))) {
Policy.Bool = BoolMacro->isObjectLike() &&
BoolMacro->getNumTokens() == 1 &&
return Policy;
void Sema::ActOnTranslationUnitScope(Scope *S) {
TUScope = S;
PushDeclContext(S, Context.getTranslationUnitDecl());
VAListTagName = PP.getIdentifierInfo("__va_list_tag");
Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
TranslationUnitKind TUKind,
CodeCompleteConsumer *CodeCompleter)
: ExternalSource(0),
isMultiplexExternalSource(false), FPFeatures(pp.getLangOpts()),
LangOpts(pp.getLangOpts()), PP(pp), Context(ctxt), Consumer(consumer),
Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
CollectStats(false), CodeCompleter(CodeCompleter),
CurContext(0), OriginalLexicalContext(0),
PackContext(0), MSStructPragmaOn(false),
VtorDispModeStack(1, MSVtorDispAttr::Mode(LangOpts.VtorDispMode)),
DataSegStack(nullptr), BSSSegStack(nullptr), ConstSegStack(nullptr),
CodeSegStack(nullptr), VisContext(0),
ExprNeedsCleanups(false), LateTemplateParser(0), OpaqueParser(0),
IdResolver(pp), StdInitializerList(0), CXXTypeInfoDecl(0), MSVCGuidDecl(0),
NSStringDecl(0), StringWithUTF8StringMethod(0),
NSArrayDecl(0), ArrayWithObjectsMethod(0),
NSDictionaryDecl(0), DictionaryWithObjectsMethod(0),
AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
CurrentInstantiationScope(0), DisableTypoCorrection(false),
TyposCorrected(0), AnalysisWarnings(*this),
VarDataSharingAttributesStack(0), CurScope(0),
Ident_super(0), Ident___float128(0)
TUScope = 0;
LoadedExternalKnownNamespaces = false;
for (unsigned I = 0; I != NSAPI::NumNSNumberLiteralMethods; ++I)
NSNumberLiteralMethods[I] = 0;
if (getLangOpts().ObjC1)
NSAPIObj.reset(new NSAPI(Context));
if (getLangOpts().CPlusPlus)
FieldCollector.reset(new CXXFieldCollector());
// Tell diagnostics how to render things from the AST library.
ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0,
false, 0, false));
FunctionScopes.push_back(new FunctionScopeInfo(Diags));
// Initilization of data sharing attributes stack for OpenMP
void Sema::addImplicitTypedef(StringRef Name, QualType T) {
DeclarationName DN = &Context.Idents.get(Name);
if (IdResolver.begin(DN) == IdResolver.end())
PushOnScopeChains(Context.buildImplicitTypedef(T, Name), TUScope);
void Sema::Initialize() {
// Tell the AST consumer about this Sema object.
// FIXME: Isn't this redundant with the initialization above?
if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
// Tell the external Sema source about this Sema object.
if (ExternalSemaSource *ExternalSema
= dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
// Initialize predefined 128-bit integer types, if needed.
if (PP.getTargetInfo().hasInt128Type()) {
// If either of the 128-bit integer types are unavailable to name lookup,
// define them now.
DeclarationName Int128 = &Context.Idents.get("__int128_t");
if (IdResolver.begin(Int128) == IdResolver.end())
PushOnScopeChains(Context.getInt128Decl(), TUScope);
DeclarationName UInt128 = &Context.Idents.get("__uint128_t");
if (IdResolver.begin(UInt128) == IdResolver.end())
PushOnScopeChains(Context.getUInt128Decl(), TUScope);
// Initialize predefined Objective-C types:
if (PP.getLangOpts().ObjC1) {
// If 'SEL' does not yet refer to any declarations, make it refer to the
// predefined 'SEL'.
DeclarationName SEL = &Context.Idents.get("SEL");
if (IdResolver.begin(SEL) == IdResolver.end())
PushOnScopeChains(Context.getObjCSelDecl(), TUScope);
// If 'id' does not yet refer to any declarations, make it refer to the
// predefined 'id'.
DeclarationName Id = &Context.Idents.get("id");
if (IdResolver.begin(Id) == IdResolver.end())
PushOnScopeChains(Context.getObjCIdDecl(), TUScope);
// Create the built-in typedef for 'Class'.
DeclarationName Class = &Context.Idents.get("Class");
if (IdResolver.begin(Class) == IdResolver.end())
PushOnScopeChains(Context.getObjCClassDecl(), TUScope);
// Create the built-in forward declaratino for 'Protocol'.
DeclarationName Protocol = &Context.Idents.get("Protocol");
if (IdResolver.begin(Protocol) == IdResolver.end())
PushOnScopeChains(Context.getObjCProtocolDecl(), TUScope);
// Initialize Microsoft "predefined C++ types".
if (PP.getLangOpts().MSVCCompat && PP.getLangOpts().CPlusPlus) {
if (IdResolver.begin(&Context.Idents.get("type_info")) == IdResolver.end())
PushOnScopeChains(Context.buildImplicitRecord("type_info", TTK_Class),
addImplicitTypedef("size_t", Context.getSizeType());
// Initialize predefined OpenCL types.
if (PP.getLangOpts().OpenCL) {
addImplicitTypedef("image1d_t", Context.OCLImage1dTy);
addImplicitTypedef("image1d_array_t", Context.OCLImage1dArrayTy);
addImplicitTypedef("image1d_buffer_t", Context.OCLImage1dBufferTy);
addImplicitTypedef("image2d_t", Context.OCLImage2dTy);
addImplicitTypedef("image2d_array_t", Context.OCLImage2dArrayTy);
addImplicitTypedef("image3d_t", Context.OCLImage3dTy);
addImplicitTypedef("sampler_t", Context.OCLSamplerTy);
addImplicitTypedef("event_t", Context.OCLEventTy);
DeclarationName BuiltinVaList = &Context.Idents.get("__builtin_va_list");
if (IdResolver.begin(BuiltinVaList) == IdResolver.end())
PushOnScopeChains(Context.getBuiltinVaListDecl(), TUScope);
Sema::~Sema() {
if (PackContext) FreePackedContext();
if (VisContext) FreeVisContext();
// Kill all the active scopes.
for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I)
delete FunctionScopes[I];
if (FunctionScopes.size() == 1)
delete FunctionScopes[0];
// Tell the SemaConsumer to forget about us; we're going out of scope.
if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer))
// Detach from the external Sema source.
if (ExternalSemaSource *ExternalSema
= dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource()))
// If Sema's ExternalSource is the multiplexer - we own it.
if (isMultiplexExternalSource)
delete ExternalSource;
// Destroys data sharing attributes stack for OpenMP
/// makeUnavailableInSystemHeader - There is an error in the current
/// context. If we're still in a system header, and we can plausibly
/// make the relevant declaration unavailable instead of erroring, do
/// so and return true.
bool Sema::makeUnavailableInSystemHeader(SourceLocation loc,
StringRef msg) {
// If we're not in a function, it's an error.
FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext);
if (!fn) return false;
// If we're in template instantiation, it's an error.
if (!ActiveTemplateInstantiations.empty())
return false;
// If that function's not in a system header, it's an error.
if (!Context.getSourceManager().isInSystemHeader(loc))
return false;
// If the function is already unavailable, it's not an error.
if (fn->hasAttr<UnavailableAttr>()) return true;
fn->addAttr(UnavailableAttr::CreateImplicit(Context, msg, loc));
return true;
ASTMutationListener *Sema::getASTMutationListener() const {
return getASTConsumer().GetASTMutationListener();
///\brief Registers an external source. If an external source already exists,
/// creates a multiplex external source and appends to it.
///\param[in] E - A non-null external sema source.
void Sema::addExternalSource(ExternalSemaSource *E) {
assert(E && "Cannot use with NULL ptr");
if (!ExternalSource) {
ExternalSource = E;
if (isMultiplexExternalSource)
else {
ExternalSource = new MultiplexExternalSemaSource(*ExternalSource, *E);
isMultiplexExternalSource = true;
/// \brief Print out statistics about the semantic analysis.
void Sema::PrintStats() const {
llvm::errs() << "\n*** Semantic Analysis Stats:\n";
llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n";
/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
/// If there is already an implicit cast, merge into the existing one.
/// The result is of the given category.
ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty,
CastKind Kind, ExprValueKind VK,
const CXXCastPath *BasePath,
CheckedConversionKind CCK) {
#ifndef NDEBUG
if (VK == VK_RValue && !E->isRValue()) {
switch (Kind) {
assert(0 && "can't implicitly cast lvalue to rvalue with this cast kind");
case CK_LValueToRValue:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_ToVoid:
assert((VK == VK_RValue || !E->isRValue()) && "can't cast rvalue to lvalue");
QualType ExprTy = Context.getCanonicalType(E->getType());
QualType TypeTy = Context.getCanonicalType(Ty);
if (ExprTy == TypeTy)
return Owned(E);
// If this is a derived-to-base cast to a through a virtual base, we
// need a vtable.
if (Kind == CK_DerivedToBase &&
BasePathInvolvesVirtualBase(*BasePath)) {
QualType T = E->getType();
if (const PointerType *Pointer = T->getAs<PointerType>())
T = Pointer->getPointeeType();
if (const RecordType *RecordTy = T->getAs<RecordType>())
if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) {
return Owned(E);
return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK));
/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
/// to the conversion from scalar type ScalarTy to the Boolean type.
CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) {
switch (ScalarTy->getScalarTypeKind()) {
case Type::STK_Bool: return CK_NoOp;
case Type::STK_CPointer: return CK_PointerToBoolean;
case Type::STK_BlockPointer: return CK_PointerToBoolean;
case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean;
case Type::STK_MemberPointer: return CK_MemberPointerToBoolean;
case Type::STK_Integral: return CK_IntegralToBoolean;
case Type::STK_Floating: return CK_FloatingToBoolean;
case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean;
case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean;
return CK_Invalid;
/// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector.
static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
if (D->getMostRecentDecl()->isUsed())
return true;
if (D->isExternallyVisible())
return true;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// UnusedFileScopedDecls stores the first declaration.
// The declaration may have become definition so check again.
const FunctionDecl *DeclToCheck;
if (FD->hasBody(DeclToCheck))
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
// Later redecls may add new information resulting in not having to warn,
// so check again.
DeclToCheck = FD->getMostRecentDecl();
if (DeclToCheck != FD)
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
// If a variable usable in constant expressions is referenced,
// don't warn if it isn't used: if the value of a variable is required
// for the computation of a constant expression, it doesn't make sense to
// warn even if the variable isn't odr-used. (isReferenced doesn't
// precisely reflect that, but it's a decent approximation.)
if (VD->isReferenced() &&
return true;
// UnusedFileScopedDecls stores the first declaration.
// The declaration may have become definition so check again.
const VarDecl *DeclToCheck = VD->getDefinition();
if (DeclToCheck)
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
// Later redecls may add new information resulting in not having to warn,
// so check again.
DeclToCheck = VD->getMostRecentDecl();
if (DeclToCheck != VD)
return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck);
return false;
/// Obtains a sorted list of functions that are undefined but ODR-used.
void Sema::getUndefinedButUsed(
SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined) {
for (llvm::DenseMap<NamedDecl *, SourceLocation>::iterator
I = UndefinedButUsed.begin(), E = UndefinedButUsed.end();
I != E; ++I) {
NamedDecl *ND = I->first;
// Ignore attributes that have become invalid.
if (ND->isInvalidDecl()) continue;
// __attribute__((weakref)) is basically a definition.
if (ND->hasAttr<WeakRefAttr>()) continue;
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
if (FD->isDefined())
if (FD->isExternallyVisible() &&
} else {
if (cast<VarDecl>(ND)->hasDefinition() != VarDecl::DeclarationOnly)
if (ND->isExternallyVisible())
Undefined.push_back(std::make_pair(ND, I->second));
// Sort (in order of use site) so that we're not dependent on the iteration
// order through an llvm::DenseMap.
SourceManager &SM = Context.getSourceManager();
std::sort(Undefined.begin(), Undefined.end(),
[&SM](const std::pair<NamedDecl *, SourceLocation> &l,
const std::pair<NamedDecl *, SourceLocation> &r) {
if (l.second.isValid() && !r.second.isValid())
return true;
if (!l.second.isValid() && r.second.isValid())
return false;
if (l.second != r.second)
return SM.isBeforeInTranslationUnit(l.second, r.second);
return SM.isBeforeInTranslationUnit(l.first->getLocation(),
/// checkUndefinedButUsed - Check for undefined objects with internal linkage
/// or that are inline.
static void checkUndefinedButUsed(Sema &S) {
if (S.UndefinedButUsed.empty()) return;
// Collect all the still-undefined entities with internal linkage.
SmallVector<std::pair<NamedDecl *, SourceLocation>, 16> Undefined;
if (Undefined.empty()) return;
for (SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> >::iterator
I = Undefined.begin(), E = Undefined.end(); I != E; ++I) {
NamedDecl *ND = I->first;
if (!ND->isExternallyVisible()) {
S.Diag(ND->getLocation(), diag::warn_undefined_internal)
<< isa<VarDecl>(ND) << ND;
} else {
assert(cast<FunctionDecl>(ND)->getMostRecentDecl()->isInlined() &&
"used object requires definition but isn't inline or internal?");
S.Diag(ND->getLocation(), diag::warn_undefined_inline) << ND;
if (I->second.isValid())
S.Diag(I->second, diag::note_used_here);
void Sema::LoadExternalWeakUndeclaredIdentifiers() {
if (!ExternalSource)
SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs;
for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) {
llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos
= WeakUndeclaredIdentifiers.find(WeakIDs[I].first);
if (Pos != WeakUndeclaredIdentifiers.end())
typedef llvm::DenseMap<const CXXRecordDecl*, bool> RecordCompleteMap;
/// \brief Returns true, if all methods and nested classes of the given
/// CXXRecordDecl are defined in this translation unit.
/// Should only be called from ActOnEndOfTranslationUnit so that all
/// definitions are actually read.
static bool MethodsAndNestedClassesComplete(const CXXRecordDecl *RD,
RecordCompleteMap &MNCComplete) {
RecordCompleteMap::iterator Cache = MNCComplete.find(RD);
if (Cache != MNCComplete.end())
return Cache->second;
if (!RD->isCompleteDefinition())
return false;
bool Complete = true;
for (DeclContext::decl_iterator I = RD->decls_begin(),
E = RD->decls_end();
I != E && Complete; ++I) {
if (const CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(*I))
Complete = M->isDefined() || (M->isPure() && !isa<CXXDestructorDecl>(M));
else if (const FunctionTemplateDecl *F = dyn_cast<FunctionTemplateDecl>(*I))
Complete = F->getTemplatedDecl()->isDefined();
else if (const CXXRecordDecl *R = dyn_cast<CXXRecordDecl>(*I)) {
if (R->isInjectedClassName())
if (R->hasDefinition())
Complete = MethodsAndNestedClassesComplete(R->getDefinition(),
Complete = false;
MNCComplete[RD] = Complete;
return Complete;
/// \brief Returns true, if the given CXXRecordDecl is fully defined in this
/// translation unit, i.e. all methods are defined or pure virtual and all
/// friends, friend functions and nested classes are fully defined in this
/// translation unit.
/// Should only be called from ActOnEndOfTranslationUnit so that all
/// definitions are actually read.
static bool IsRecordFullyDefined(const CXXRecordDecl *RD,
RecordCompleteMap &RecordsComplete,
RecordCompleteMap &MNCComplete) {
RecordCompleteMap::iterator Cache = RecordsComplete.find(RD);
if (Cache != RecordsComplete.end())
return Cache->second;
bool Complete = MethodsAndNestedClassesComplete(RD, MNCComplete);
for (CXXRecordDecl::friend_iterator I = RD->friend_begin(),
E = RD->friend_end();
I != E && Complete; ++I) {
// Check if friend classes and methods are complete.
if (TypeSourceInfo *TSI = (*I)->getFriendType()) {
// Friend classes are available as the TypeSourceInfo of the FriendDecl.
if (CXXRecordDecl *FriendD = TSI->getType()->getAsCXXRecordDecl())
Complete = MethodsAndNestedClassesComplete(FriendD, MNCComplete);
Complete = false;
} else {
// Friend functions are available through the NamedDecl of FriendDecl.
if (const FunctionDecl *FD =
Complete = FD->isDefined();
// This is a template friend, give up.
Complete = false;
RecordsComplete[RD] = Complete;
return Complete;
/// ActOnEndOfTranslationUnit - This is called at the very end of the
/// translation unit when EOF is reached and all but the top-level scope is
/// popped.
void Sema::ActOnEndOfTranslationUnit() {
assert(DelayedDiagnostics.getCurrentPool() == NULL
&& "reached end of translation unit with a pool attached?");
// If code completion is enabled, don't perform any end-of-translation-unit
// work.
if (PP.isCodeCompletionEnabled())
// Complete translation units and modules define vtables and perform implicit
// instantiations. PCH files do not.
if (TUKind != TU_Prefix) {
// If any dynamic classes have their key function defined within
// this translation unit, then those vtables are considered "used" and must
// be emitted.
for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource),
E = DynamicClasses.end();
I != E; ++I) {
assert(!(*I)->isDependentType() &&
"Should not see dependent types here!");
if (const CXXMethodDecl *KeyFunction = Context.getCurrentKeyFunction(*I)) {
const FunctionDecl *Definition = 0;
if (KeyFunction->hasBody(Definition))
MarkVTableUsed(Definition->getLocation(), *I, true);
// If DefinedUsedVTables ends up marking any virtual member functions it
// might lead to more pending template instantiations, which we then need
// to instantiate.
// C++: Perform implicit template instantiations.
// FIXME: When we perform these implicit instantiations, we do not
// carefully keep track of the point of instantiation (C++ [temp.point]).
// This means that name lookup that occurs within the template
// instantiation will always happen at the end of the translation unit,
// so it will find some names that are not required to be found. This is
// valid, but we could do better by diagnosing if an instantiation uses a
// name that was not visible at its first point of instantiation.
if (ExternalSource) {
// Load pending instantiations from the external source.
SmallVector<PendingImplicitInstantiation, 4> Pending;
Pending.begin(), Pending.end());
// All delayed member exception specs should be checked or we end up accepting
// incompatible declarations.
// Remove file scoped decls that turned out to be used.
std::remove_if(UnusedFileScopedDecls.begin(0, true),
std::bind1st(std::ptr_fun(ShouldRemoveFromUnused), this)),
if (TUKind == TU_Prefix) {
// Translation unit prefixes don't need any of the checking below.
TUScope = 0;
// Check for #pragma weak identifiers that were never declared
// FIXME: This will cause diagnostics to be emitted in a non-determinstic
// order! Iterating over a densemap like this is bad.
for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
I = WeakUndeclaredIdentifiers.begin(),
E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
if (I->second.getUsed()) continue;
Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
<< I->first;
if (LangOpts.CPlusPlus11 &&
!= DiagnosticsEngine::Ignored)
if (TUKind == TU_Module) {
// If we are building a module, resolve all of the exported declarations
// now.
if (Module *CurrentModule = PP.getCurrentModule()) {
ModuleMap &ModMap = PP.getHeaderSearchInfo().getModuleMap();
SmallVector<Module *, 2> Stack;
while (!Stack.empty()) {
Module *Mod = Stack.pop_back_val();
// Resolve the exported declarations and conflicts.
// FIXME: Actually complain, once we figure out how to teach the
// diagnostic client to deal with complaints in the module map at this
// point.
ModMap.resolveExports(Mod, /*Complain=*/false);
ModMap.resolveUses(Mod, /*Complain=*/false);
ModMap.resolveConflicts(Mod, /*Complain=*/false);
// Queue the submodules, so their exports will also be resolved.
for (Module::submodule_iterator Sub = Mod->submodule_begin(),
SubEnd = Mod->submodule_end();
Sub != SubEnd; ++Sub) {
// Modules don't need any of the checking below.
TUScope = 0;
// C99 6.9.2p2:
// A declaration of an identifier for an object that has file
// scope without an initializer, and without a storage-class
// specifier or with the storage-class specifier static,
// constitutes a tentative definition. If a translation unit
// contains one or more tentative definitions for an identifier,
// and the translation unit contains no external definition for
// that identifier, then the behavior is exactly as if the
// translation unit contains a file scope declaration of that
// identifier, with the composite type as of the end of the
// translation unit, with an initializer equal to 0.
llvm::SmallSet<VarDecl *, 32> Seen;
for (TentativeDefinitionsType::iterator
T = TentativeDefinitions.begin(ExternalSource),
TEnd = TentativeDefinitions.end();
T != TEnd; ++T)
VarDecl *VD = (*T)->getActingDefinition();
// If the tentative definition was completed, getActingDefinition() returns
// null. If we've already seen this variable before, insert()'s second
// return value is false.
if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
if (const IncompleteArrayType *ArrayT
= Context.getAsIncompleteArrayType(VD->getType())) {
// Set the length of the array to 1 (C99 6.9.2p5).
Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
QualType T = Context.getConstantArrayType(ArrayT->getElementType(),
One, ArrayType::Normal, 0);
} else if (RequireCompleteType(VD->getLocation(), VD->getType(),
// Notify the consumer that we've completed a tentative definition.
if (!VD->isInvalidDecl())
// If there were errors, disable 'unused' warnings since they will mostly be
// noise.
if (!Diags.hasErrorOccurred()) {
// Output warning for unused file scoped decls.
for (UnusedFileScopedDeclsType::iterator
I = UnusedFileScopedDecls.begin(ExternalSource),
E = UnusedFileScopedDecls.end(); I != E; ++I) {
if (ShouldRemoveFromUnused(this, *I))
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
const FunctionDecl *DiagD;
if (!FD->hasBody(DiagD))
DiagD = FD;
if (DiagD->isDeleted())
continue; // Deleted functions are supposed to be unused.
if (DiagD->isReferenced()) {
if (isa<CXXMethodDecl>(DiagD))
Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
<< DiagD->getDeclName();
else {
if (FD->getStorageClass() == SC_Static &&
!FD->isInlineSpecified() &&
Diag(DiagD->getLocation(), diag::warn_unneeded_static_internal_decl)
<< DiagD->getDeclName();
Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
<< /*function*/0 << DiagD->getDeclName();
} else {
isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
: diag::warn_unused_function)
<< DiagD->getDeclName();
} else {
const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
if (!DiagD)
DiagD = cast<VarDecl>(*I);
if (DiagD->isReferenced()) {
Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
<< /*variable*/1 << DiagD->getDeclName();
} else if (DiagD->getType().isConstQualified()) {
Diag(DiagD->getLocation(), diag::warn_unused_const_variable)
<< DiagD->getDeclName();
} else {
Diag(DiagD->getLocation(), diag::warn_unused_variable)
<< DiagD->getDeclName();
if (ExternalSource)
if (Diags.getDiagnosticLevel(diag::warn_unused_private_field,
!= DiagnosticsEngine::Ignored) {
RecordCompleteMap RecordsComplete;
RecordCompleteMap MNCComplete;
for (NamedDeclSetType::iterator I = UnusedPrivateFields.begin(),
E = UnusedPrivateFields.end(); I != E; ++I) {
const NamedDecl *D = *I;
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());
if (RD && !RD->isUnion() &&
IsRecordFullyDefined(RD, RecordsComplete, MNCComplete)) {
Diag(D->getLocation(), diag::warn_unused_private_field)
<< D->getDeclName();
// Check we've noticed that we're no longer parsing the initializer for every
// variable. If we miss cases, then at best we have a performance issue and
// at worst a rejects-valid bug.
assert(ParsingInitForAutoVars.empty() &&
"Didn't unmark var as having its initializer parsed");
TUScope = 0;
// Helper functions.
DeclContext *Sema::getFunctionLevelDeclContext() {
DeclContext *DC = CurContext;
while (true) {
if (isa<BlockDecl>(DC) || isa<EnumDecl>(DC) || isa<CapturedDecl>(DC)) {
DC = DC->getParent();
} else if (isa<CXXMethodDecl>(DC) &&
cast<CXXMethodDecl>(DC)->getOverloadedOperator() == OO_Call &&
cast<CXXRecordDecl>(DC->getParent())->isLambda()) {
DC = DC->getParent()->getParent();
else break;
return DC;
/// getCurFunctionDecl - If inside of a function body, this returns a pointer
/// to the function decl for the function being parsed. If we're currently
/// in a 'block', this returns the containing context.
FunctionDecl *Sema::getCurFunctionDecl() {
DeclContext *DC = getFunctionLevelDeclContext();
return dyn_cast<FunctionDecl>(DC);
ObjCMethodDecl *Sema::getCurMethodDecl() {
DeclContext *DC = getFunctionLevelDeclContext();
while (isa<RecordDecl>(DC))
DC = DC->getParent();
return dyn_cast<ObjCMethodDecl>(DC);
NamedDecl *Sema::getCurFunctionOrMethodDecl() {
DeclContext *DC = getFunctionLevelDeclContext();
if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
return cast<NamedDecl>(DC);
return 0;
void Sema::EmitCurrentDiagnostic(unsigned DiagID) {
// FIXME: It doesn't make sense to me that DiagID is an incoming argument here
// and yet we also use the current diag ID on the DiagnosticsEngine. This has
// been made more painfully obvious by the refactor that introduced this
// function, but it is possible that the incoming argument can be
// eliminnated. If it truly cannot be (for example, there is some reentrancy
// issue I am not seeing yet), then there should at least be a clarifying
// comment somewhere.
if (Optional<TemplateDeductionInfo*> Info = isSFINAEContext()) {
switch (DiagnosticIDs::getDiagnosticSFINAEResponse(
Diags.getCurrentDiagID())) {
case DiagnosticIDs::SFINAE_Report:
// We'll report the diagnostic below.
case DiagnosticIDs::SFINAE_SubstitutionFailure:
// Count this failure so that we know that template argument deduction
// has failed.
// Make a copy of this suppressed diagnostic and store it with the
// template-deduction information.
if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
Diagnostic DiagInfo(&Diags);
PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
case DiagnosticIDs::SFINAE_AccessControl: {
// Per C++ Core Issue 1170, access control is part of SFINAE.
// Additionally, the AccessCheckingSFINAE flag can be used to temporarily
// make access control a part of SFINAE for the purposes of checking
// type traits.
if (!AccessCheckingSFINAE && !getLangOpts().CPlusPlus11)
SourceLocation Loc = Diags.getCurrentDiagLoc();
// Suppress this diagnostic.
// Make a copy of this suppressed diagnostic and store it with the
// template-deduction information.
if (*Info && !(*Info)->hasSFINAEDiagnostic()) {
Diagnostic DiagInfo(&Diags);
PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
// Now the diagnostic state is clear, produce a C++98 compatibility
// warning.
Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control);
// The last diagnostic which Sema produced was ignored. Suppress any
// notes attached to it.
case DiagnosticIDs::SFINAE_Suppress:
// Make a copy of this suppressed diagnostic and store it with the
// template-deduction information;
if (*Info) {
Diagnostic DiagInfo(&Diags);
PartialDiagnostic(DiagInfo, Context.getDiagAllocator()));
// Suppress this diagnostic.
// Set up the context's printing policy based on our current state.
// Emit the diagnostic.
if (!Diags.EmitCurrentDiagnostic())
// If this is not a note, and we're in a template instantiation
// that is different from the last template instantiation where
// we emitted an error, print a template instantiation
// backtrace.
if (!DiagnosticIDs::isBuiltinNote(DiagID) &&
!ActiveTemplateInstantiations.empty() &&
!= LastTemplateInstantiationErrorContext) {
LastTemplateInstantiationErrorContext = ActiveTemplateInstantiations.back();
Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
return Builder;
/// \brief Looks through the macro-expansion chain for the given
/// location, looking for a macro expansion with the given name.
/// If one is found, returns true and sets the location to that
/// expansion loc.
bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
SourceLocation loc = locref;
if (!loc.isMacroID()) return false;
// There's no good way right now to look at the intermediate
// expansions, so just jump to the expansion location.
loc = getSourceManager().getExpansionLoc(loc);
// If that's written with the name, stop here.
SmallVector<char, 16> buffer;
if (getPreprocessor().getSpelling(loc, buffer) == name) {
locref = loc;
return true;
return false;
/// \brief Determines the active Scope associated with the given declaration
/// context.
/// This routine maps a declaration context to the active Scope object that
/// represents that declaration context in the parser. It is typically used
/// from "scope-less" code (e.g., template instantiation, lazy creation of
/// declarations) that injects a name for name-lookup purposes and, therefore,
/// must update the Scope.
/// \returns The scope corresponding to the given declaraion context, or NULL
/// if no such scope is open.
Scope *Sema::getScopeForContext(DeclContext *Ctx) {
if (!Ctx)
return 0;
Ctx = Ctx->getPrimaryContext();
for (Scope *S = getCurScope(); S; S = S->getParent()) {
// Ignore scopes that cannot have declarations. This is important for
// out-of-line definitions of static class members.
if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope))
if (DeclContext *Entity = S->getEntity())
if (Ctx == Entity->getPrimaryContext())
return S;
return 0;
/// \brief Enter a new function scope
void Sema::PushFunctionScope() {
if (FunctionScopes.size() == 1) {
// Use the "top" function scope rather than having to allocate
// memory for a new scope.
FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics()));
void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(),
BlockScope, Block));
LambdaScopeInfo *Sema::PushLambdaScope() {
LambdaScopeInfo *const LSI = new LambdaScopeInfo(getDiagnostics());
return LSI;
void Sema::RecordParsingTemplateParameterDepth(unsigned Depth) {
if (LambdaScopeInfo *const LSI = getCurLambda()) {
LSI->AutoTemplateParameterDepth = Depth;
"Remove assertion if intentionally called in a non-lambda context.");
void Sema::PopFunctionScopeInfo(const AnalysisBasedWarnings::Policy *WP,
const Decl *D, const BlockExpr *blkExpr) {
FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
assert(!FunctionScopes.empty() && "mismatched push/pop!");
// Issue any analysis-based warnings.
if (WP && D)
AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
else {
for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
i = Scope->PossiblyUnreachableDiags.begin(),
e = Scope->PossiblyUnreachableDiags.end();
i != e; ++i) {
const sema::PossiblyUnreachableDiag &D = *i;
Diag(D.Loc, D.PD);
if (FunctionScopes.back() != Scope) {
delete Scope;
void Sema::PushCompoundScope() {
void Sema::PopCompoundScope() {
FunctionScopeInfo *CurFunction = getCurFunction();
assert(!CurFunction->CompoundScopes.empty() && "mismatched push/pop");
/// \brief Determine whether any errors occurred within this function/method/
/// block.
bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const {
return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred();
BlockScopeInfo *Sema::getCurBlock() {
if (FunctionScopes.empty())
return 0;
auto CurBSI = dyn_cast<BlockScopeInfo>(FunctionScopes.back());
if (CurBSI && CurBSI->TheDecl &&
!CurBSI->TheDecl->Encloses(CurContext)) {
// We have switched contexts due to template instantiation.
return nullptr;
return CurBSI;
LambdaScopeInfo *Sema::getCurLambda() {
if (FunctionScopes.empty())
return 0;
auto CurLSI = dyn_cast<LambdaScopeInfo>(FunctionScopes.back());
if (CurLSI && CurLSI->Lambda &&
!CurLSI->Lambda->Encloses(CurContext)) {
// We have switched contexts due to template instantiation.
return nullptr;
return CurLSI;
// We have a generic lambda if we parsed auto parameters, or we have
// an associated template parameter list.
LambdaScopeInfo *Sema::getCurGenericLambda() {
if (LambdaScopeInfo *LSI = getCurLambda()) {
return (LSI->AutoTemplateParams.size() ||
LSI->GLTemplateParameterList) ? LSI : 0;
return 0;
void Sema::ActOnComment(SourceRange Comment) {
if (!LangOpts.RetainCommentsFromSystemHeaders &&
RawComment RC(SourceMgr, Comment, false,
if (RC.isAlmostTrailingComment()) {
SourceRange MagicMarkerRange(Comment.getBegin(),
StringRef MagicMarkerText;
switch (RC.getKind()) {
case RawComment::RCK_OrdinaryBCPL:
MagicMarkerText = "///<";
case RawComment::RCK_OrdinaryC:
MagicMarkerText = "/**<";
llvm_unreachable("if this is an almost Doxygen comment, "
"it should be ordinary");
Diag(Comment.getBegin(), diag::warn_not_a_doxygen_trailing_member_comment) <<
FixItHint::CreateReplacement(MagicMarkerRange, MagicMarkerText);
// Pin this vtable to this file.
ExternalSemaSource::~ExternalSemaSource() {}
void ExternalSemaSource::ReadMethodPool(Selector Sel) { }
void ExternalSemaSource::ReadKnownNamespaces(
SmallVectorImpl<NamespaceDecl *> &Namespaces) {
void ExternalSemaSource::ReadUndefinedButUsed(
llvm::DenseMap<NamedDecl *, SourceLocation> &Undefined) {
void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
SourceLocation Loc = this->Loc;
if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
if (Loc.isValid()) {
Loc.print(OS, S.getSourceManager());
OS << ": ";
OS << Message;
if (TheDecl && isa<NamedDecl>(TheDecl)) {
std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString();
if (!Name.empty())
OS << " '" << Name << '\'';
OS << '\n';
/// \brief Figure out if an expression could be turned into a call.
/// Use this when trying to recover from an error where the programmer may have
/// written just the name of a function instead of actually calling it.
/// \param E - The expression to examine.
/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
/// with no arguments, this parameter is set to the type returned by such a
/// call; otherwise, it is set to an empty QualType.
/// \param OverloadSet - If the expression is an overloaded function
/// name, this parameter is populated with the decls of the various overloads.
bool Sema::tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
UnresolvedSetImpl &OverloadSet) {
ZeroArgCallReturnTy = QualType();
const OverloadExpr *Overloads = NULL;
bool IsMemExpr = false;
if (E.getType() == Context.OverloadTy) {
OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E));
// Ignore overloads that are pointer-to-member constants.
if (FR.HasFormOfMemberPointer)
return false;
Overloads = FR.Expression;
} else if (E.getType() == Context.BoundMemberTy) {
Overloads = dyn_cast<UnresolvedMemberExpr>(E.IgnoreParens());
IsMemExpr = true;
bool Ambiguous = false;
if (Overloads) {
for (OverloadExpr::decls_iterator it = Overloads->decls_begin(),
DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) {
// Check whether the function is a non-template, non-member which takes no
// arguments.
if (IsMemExpr)
if (const FunctionDecl *OverloadDecl
= dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) {
if (OverloadDecl->getMinRequiredArguments() == 0) {
if (!ZeroArgCallReturnTy.isNull() && !Ambiguous) {
ZeroArgCallReturnTy = QualType();
Ambiguous = true;
} else
ZeroArgCallReturnTy = OverloadDecl->getReturnType();
// If it's not a member, use better machinery to try to resolve the call
if (!IsMemExpr)
return !ZeroArgCallReturnTy.isNull();
// Attempt to call the member with no arguments - this will correctly handle
// member templates with defaults/deduction of template arguments, overloads
// with default arguments, etc.
if (IsMemExpr && !E.isTypeDependent()) {
bool Suppress = getDiagnostics().getSuppressAllDiagnostics();
ExprResult R = BuildCallToMemberFunction(NULL, &E, SourceLocation(), None,
if (R.isUsable()) {
ZeroArgCallReturnTy = R.get()->getType();
return true;
return false;
if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) {
if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
if (Fun->getMinRequiredArguments() == 0)
ZeroArgCallReturnTy = Fun->getReturnType();
return true;
// We don't have an expression that's convenient to get a FunctionDecl from,
// but we can at least check if the type is "function of 0 arguments".
QualType ExprTy = E.getType();
const FunctionType *FunTy = NULL;
QualType PointeeTy = ExprTy->getPointeeType();
if (!PointeeTy.isNull())
FunTy = PointeeTy->getAs<FunctionType>();
if (!FunTy)
FunTy = ExprTy->getAs<FunctionType>();
if (const FunctionProtoType *FPT =
dyn_cast_or_null<FunctionProtoType>(FunTy)) {
if (FPT->getNumParams() == 0)
ZeroArgCallReturnTy = FunTy->getReturnType();
return true;
return false;
/// \brief Give notes for a set of overloads.
/// A companion to tryExprAsCall. In cases when the name that the programmer
/// wrote was an overloaded function, we may be able to make some guesses about
/// plausible overloads based on their return types; such guesses can be handed
/// off to this method to be emitted as notes.
/// \param Overloads - The overloads to note.
/// \param FinalNoteLoc - If we've suppressed printing some overloads due to
/// -fshow-overloads=best, this is the location to attach to the note about too
/// many candidates. Typically this will be the location of the original
/// ill-formed expression.
static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads,
const SourceLocation FinalNoteLoc) {
int ShownOverloads = 0;
int SuppressedOverloads = 0;
for (UnresolvedSetImpl::iterator It = Overloads.begin(),
DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
// FIXME: Magic number for max shown overloads stolen from
// OverloadCandidateSet::NoteCandidates.
if (ShownOverloads >= 4 && S.Diags.getShowOverloads() == Ovl_Best) {
NamedDecl *Fn = (*It)->getUnderlyingDecl();
S.Diag(Fn->getLocation(), diag::note_possible_target_of_call);
if (SuppressedOverloads)
S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates)
<< SuppressedOverloads;
static void notePlausibleOverloads(Sema &S, SourceLocation Loc,
const UnresolvedSetImpl &Overloads,
bool (*IsPlausibleResult)(QualType)) {
if (!IsPlausibleResult)
return noteOverloads(S, Overloads, Loc);
UnresolvedSet<2> PlausibleOverloads;
for (OverloadExpr::decls_iterator It = Overloads.begin(),
DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) {
const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It);
QualType OverloadResultTy = OverloadDecl->getReturnType();
if (IsPlausibleResult(OverloadResultTy))
noteOverloads(S, PlausibleOverloads, Loc);
/// Determine whether the given expression can be called by just
/// putting parentheses after it. Notably, expressions with unary
/// operators can't be because the unary operator will start parsing
/// outside the call.
static bool IsCallableWithAppend(Expr *E) {
E = E->IgnoreImplicit();
return (!isa<CStyleCastExpr>(E) &&
!isa<UnaryOperator>(E) &&
!isa<BinaryOperator>(E) &&
bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
bool ForceComplain,
bool (*IsPlausibleResult)(QualType)) {
SourceLocation Loc = E.get()->getExprLoc();
SourceRange Range = E.get()->getSourceRange();
QualType ZeroArgCallTy;
UnresolvedSet<4> Overloads;
if (tryExprAsCall(*E.get(), ZeroArgCallTy, Overloads) &&
!ZeroArgCallTy.isNull() &&
(!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) {
// At this point, we know E is potentially callable with 0
// arguments and that it returns something of a reasonable type,
// so we can emit a fixit and carry on pretending that E was
// actually a CallExpr.
SourceLocation ParenInsertionLoc = PP.getLocForEndOfToken(Range.getEnd());
Diag(Loc, PD)
<< /*zero-arg*/ 1 << Range
<< (IsCallableWithAppend(E.get())
? FixItHint::CreateInsertion(ParenInsertionLoc, "()")
: FixItHint());
notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
// FIXME: Try this before emitting the fixit, and suppress diagnostics
// while doing so.
E = ActOnCallExpr(0, E.take(), Range.getEnd(), None,
return true;
if (!ForceComplain) return false;
Diag(Loc, PD) << /*not zero-arg*/ 0 << Range;
notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult);
E = ExprError();
return true;
IdentifierInfo *Sema::getSuperIdentifier() const {
if (!Ident_super)
Ident_super = &Context.Idents.get("super");
return Ident_super;
IdentifierInfo *Sema::getFloat128Identifier() const {
if (!Ident___float128)
Ident___float128 = &Context.Idents.get("__float128");
return Ident___float128;
void Sema::PushCapturedRegionScope(Scope *S, CapturedDecl *CD, RecordDecl *RD,
CapturedRegionKind K) {
CapturingScopeInfo *CSI = new CapturedRegionScopeInfo(getDiagnostics(), S, CD, RD,
CD->getContextParam(), K);
CSI->ReturnType = Context.VoidTy;
CapturedRegionScopeInfo *Sema::getCurCapturedRegion() {
if (FunctionScopes.empty())
return 0;
return dyn_cast<CapturedRegionScopeInfo>(FunctionScopes.back());