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//===--- SemaDecl.cpp - Semantic Analysis for Declarations ----------------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file implements semantic analysis for declarations.
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/CXXFieldCollector.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "TypeLocBuilder.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/CommentDiagnostic.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/CharUnits.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
// FIXME: layering (ideally, Sema shouldn't be dependent on Lex API's)
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/ModuleLoader.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Triple.h"
#include <algorithm>
#include <cstring>
#include <functional>
using namespace clang;
using namespace sema;
Sema::DeclGroupPtrTy Sema::ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType) {
if (OwnedType) {
Decl *Group[2] = { OwnedType, Ptr };
return DeclGroupPtrTy::make(DeclGroupRef::Create(Context, Group, 2));
return DeclGroupPtrTy::make(DeclGroupRef(Ptr));
namespace {
class TypeNameValidatorCCC : public CorrectionCandidateCallback {
TypeNameValidatorCCC(bool AllowInvalid, bool WantClass=false)
: AllowInvalidDecl(AllowInvalid), WantClassName(WantClass) {
WantExpressionKeywords = false;
WantCXXNamedCasts = false;
WantRemainingKeywords = false;
virtual bool ValidateCandidate(const TypoCorrection &candidate) {
if (NamedDecl *ND = candidate.getCorrectionDecl())
return (isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND)) &&
(AllowInvalidDecl || !ND->isInvalidDecl());
return !WantClassName && candidate.isKeyword();
bool AllowInvalidDecl;
bool WantClassName;
/// \brief Determine whether the token kind starts a simple-type-specifier.
bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
switch (Kind) {
// FIXME: Take into account the current language when deciding whether a
// token kind is a valid type specifier
case tok::kw_short:
case tok::kw_long:
case tok::kw___int64:
case tok::kw___int128:
case tok::kw_signed:
case tok::kw_unsigned:
case tok::kw_void:
case tok::kw_char:
case tok::kw_int:
case tok::kw_half:
case tok::kw_float:
case tok::kw_double:
case tok::kw_wchar_t:
case tok::kw_bool:
case tok::kw___underlying_type:
return true;
case tok::annot_typename:
case tok::kw_char16_t:
case tok::kw_char32_t:
case tok::kw_typeof:
case tok::kw_decltype:
return getLangOpts().CPlusPlus;
return false;
/// \brief If the identifier refers to a type name within this scope,
/// return the declaration of that type.
/// This routine performs ordinary name lookup of the identifier II
/// within the given scope, with optional C++ scope specifier SS, to
/// determine whether the name refers to a type. If so, returns an
/// opaque pointer (actually a QualType) corresponding to that
/// type. Otherwise, returns NULL.
/// If name lookup results in an ambiguity, this routine will complain
/// and then return NULL.
ParsedType Sema::getTypeName(IdentifierInfo &II, SourceLocation NameLoc,
Scope *S, CXXScopeSpec *SS,
bool isClassName, bool HasTrailingDot,
ParsedType ObjectTypePtr,
bool IsCtorOrDtorName,
bool WantNontrivialTypeSourceInfo,
IdentifierInfo **CorrectedII) {
// Determine where we will perform name lookup.
DeclContext *LookupCtx = 0;
if (ObjectTypePtr) {
QualType ObjectType = ObjectTypePtr.get();
if (ObjectType->isRecordType())
LookupCtx = computeDeclContext(ObjectType);
} else if (SS && SS->isNotEmpty()) {
LookupCtx = computeDeclContext(*SS, false);
if (!LookupCtx) {
if (isDependentScopeSpecifier(*SS)) {
// C++ [temp.res]p3:
// A qualified-id that refers to a type and in which the
// nested-name-specifier depends on a template-parameter (14.6.2)
// shall be prefixed by the keyword typename to indicate that the
// qualified-id denotes a type, forming an
// elaborated-type-specifier (
// We therefore do not perform any name lookup if the result would
// refer to a member of an unknown specialization.
if (!isClassName && !IsCtorOrDtorName)
return ParsedType();
// We know from the grammar that this name refers to a type,
// so build a dependent node to describe the type.
if (WantNontrivialTypeSourceInfo)
return ActOnTypenameType(S, SourceLocation(), *SS, II, NameLoc).get();
NestedNameSpecifierLoc QualifierLoc = SS->getWithLocInContext(Context);
QualType T =
CheckTypenameType(ETK_None, SourceLocation(), QualifierLoc,
II, NameLoc);
return ParsedType::make(T);
return ParsedType();
if (!LookupCtx->isDependentContext() &&
RequireCompleteDeclContext(*SS, LookupCtx))
return ParsedType();
// FIXME: LookupNestedNameSpecifierName isn't the right kind of
// lookup for class-names.
LookupNameKind Kind = isClassName ? LookupNestedNameSpecifierName :
LookupResult Result(*this, &II, NameLoc, Kind);
if (LookupCtx) {
// Perform "qualified" name lookup into the declaration context we
// computed, which is either the type of the base of a member access
// expression or the declaration context associated with a prior
// nested-name-specifier.
LookupQualifiedName(Result, LookupCtx);
if (ObjectTypePtr && Result.empty()) {
// C++ [basic.lookup.classref]p3:
// If the unqualified-id is ~type-name, the type-name is looked up
// in the context of the entire postfix-expression. If the type T of
// the object expression is of a class type C, the type-name is also
// looked up in the scope of class C. At least one of the lookups shall
// find a name that refers to (possibly cv-qualified) T.
LookupName(Result, S);
} else {
// Perform unqualified name lookup.
LookupName(Result, S);
NamedDecl *IIDecl = 0;
switch (Result.getResultKind()) {
case LookupResult::NotFound:
case LookupResult::NotFoundInCurrentInstantiation:
if (CorrectedII) {
TypeNameValidatorCCC Validator(true, isClassName);
TypoCorrection Correction = CorrectTypo(Result.getLookupNameInfo(),
Kind, S, SS, Validator);
IdentifierInfo *NewII = Correction.getCorrectionAsIdentifierInfo();
TemplateTy Template;
bool MemberOfUnknownSpecialization;
UnqualifiedId TemplateName;
TemplateName.setIdentifier(NewII, NameLoc);
NestedNameSpecifier *NNS = Correction.getCorrectionSpecifier();
CXXScopeSpec NewSS, *NewSSPtr = SS;
if (SS && NNS) {
NewSS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
NewSSPtr = &NewSS;
if (Correction && (NNS || NewII != &II) &&
// Ignore a correction to a template type as the to-be-corrected
// identifier is not a template (typo correction for template names
// is handled elsewhere).
!(getLangOpts().CPlusPlus && NewSSPtr &&
isTemplateName(S, *NewSSPtr, false, TemplateName, ParsedType(),
false, Template, MemberOfUnknownSpecialization))) {
ParsedType Ty = getTypeName(*NewII, NameLoc, S, NewSSPtr,
isClassName, HasTrailingDot, ObjectTypePtr,
if (Ty) {
std::string CorrectedStr(Correction.getAsString(getLangOpts()));
std::string CorrectedQuotedStr(
Diag(NameLoc, diag::err_unknown_type_or_class_name_suggest)
<< Result.getLookupName() << CorrectedQuotedStr << isClassName
<< FixItHint::CreateReplacement(SourceRange(NameLoc),
if (NamedDecl *FirstDecl = Correction.getCorrectionDecl())
Diag(FirstDecl->getLocation(), diag::note_previous_decl)
<< CorrectedQuotedStr;
if (SS && NNS)
SS->MakeTrivial(Context, NNS, SourceRange(NameLoc));
*CorrectedII = NewII;
return Ty;
// If typo correction failed or was not performed, fall through
case LookupResult::FoundOverloaded:
case LookupResult::FoundUnresolvedValue:
return ParsedType();
case LookupResult::Ambiguous:
// Recover from type-hiding ambiguities by hiding the type. We'll
// do the lookup again when looking for an object, and we can
// diagnose the error then. If we don't do this, then the error
// about hiding the type will be immediately followed by an error
// that only makes sense if the identifier was treated like a type.
if (Result.getAmbiguityKind() == LookupResult::AmbiguousTagHiding) {
return ParsedType();
// Look to see if we have a type anywhere in the list of results.
for (LookupResult::iterator Res = Result.begin(), ResEnd = Result.end();
Res != ResEnd; ++Res) {
if (isa<TypeDecl>(*Res) || isa<ObjCInterfaceDecl>(*Res)) {
if (!IIDecl ||
(*Res)->getLocation().getRawEncoding() <
IIDecl = *Res;
if (!IIDecl) {
// None of the entities we found is a type, so there is no way
// to even assume that the result is a type. In this case, don't
// complain about the ambiguity. The parser will either try to
// perform this lookup again (e.g., as an object name), which
// will produce the ambiguity, or will complain that it expected
// a type name.
return ParsedType();
// We found a type within the ambiguous lookup; diagnose the
// ambiguity and then return that type. This might be the right
// answer, or it might not be, but it suppresses any attempt to
// perform the name lookup again.
case LookupResult::Found:
IIDecl = Result.getFoundDecl();
assert(IIDecl && "Didn't find decl");
QualType T;
if (TypeDecl *TD = dyn_cast<TypeDecl>(IIDecl)) {
DiagnoseUseOfDecl(IIDecl, NameLoc);
if (T.isNull())
T = Context.getTypeDeclType(TD);
// NOTE: avoid constructing an ElaboratedType(Loc) if this is a
// constructor or destructor name (in such a case, the scope specifier
// will be attached to the enclosing Expr or Decl node).
if (SS && SS->isNotEmpty() && !IsCtorOrDtorName) {
if (WantNontrivialTypeSourceInfo) {
// Construct a type with type-source information.
TypeLocBuilder Builder;
T = getElaboratedType(ETK_None, *SS, T);
ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
} else {
T = getElaboratedType(ETK_None, *SS, T);
} else if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(IIDecl)) {
(void)DiagnoseUseOfDecl(IDecl, NameLoc);
if (!HasTrailingDot)
T = Context.getObjCInterfaceType(IDecl);
if (T.isNull()) {
// If it's not plausibly a type, suppress diagnostics.
return ParsedType();
return ParsedType::make(T);
/// isTagName() - This method is called *for error recovery purposes only*
/// to determine if the specified name is a valid tag name ("struct foo"). If
/// so, this returns the TST for the tag corresponding to it (TST_enum,
/// TST_union, TST_struct, TST_class). This is used to diagnose cases in C
/// where the user forgot to specify the tag.
DeclSpec::TST Sema::isTagName(IdentifierInfo &II, Scope *S) {
// Do a tag name lookup in this scope.
LookupResult R(*this, &II, SourceLocation(), LookupTagName);
LookupName(R, S, false);
if (R.getResultKind() == LookupResult::Found)
if (const TagDecl *TD = R.getAsSingle<TagDecl>()) {
switch (TD->getTagKind()) {
case TTK_Struct: return DeclSpec::TST_struct;
case TTK_Union: return DeclSpec::TST_union;
case TTK_Class: return DeclSpec::TST_class;
case TTK_Enum: return DeclSpec::TST_enum;
return DeclSpec::TST_unspecified;
/// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
/// if a CXXScopeSpec's type is equal to the type of one of the base classes
/// then downgrade the missing typename error to a warning.
/// This is needed for MSVC compatibility; Example:
/// @code
/// template<class T> class A {
/// public:
/// typedef int TYPE;
/// };
/// template<class T> class B : public A<T> {
/// public:
/// A<T>::TYPE a; // no typename required because A<T> is a base class.
/// };
/// @endcode
bool Sema::isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S) {
if (CurContext->isRecord()) {
const Type *Ty = SS->getScopeRep()->getAsType();
CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
for (CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin(),
BaseEnd = RD->bases_end(); Base != BaseEnd; ++Base)
if (Context.hasSameUnqualifiedType(QualType(Ty, 1), Base->getType()))
return true;
return S->isFunctionPrototypeScope();
return CurContext->isFunctionOrMethod() || S->isFunctionPrototypeScope();
bool Sema::DiagnoseUnknownTypeName(IdentifierInfo *&II,
SourceLocation IILoc,
Scope *S,
CXXScopeSpec *SS,
ParsedType &SuggestedType) {
// We don't have anything to suggest (yet).
SuggestedType = ParsedType();
// There may have been a typo in the name of the type. Look up typo
// results, in case we have something that we can suggest.
TypeNameValidatorCCC Validator(false);
if (TypoCorrection Corrected = CorrectTypo(DeclarationNameInfo(II, IILoc),
LookupOrdinaryName, S, SS,
Validator)) {
std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
std::string CorrectedQuotedStr(Corrected.getQuoted(getLangOpts()));
if (Corrected.isKeyword()) {
// We corrected to a keyword.
IdentifierInfo *NewII = Corrected.getCorrectionAsIdentifierInfo();
if (!isSimpleTypeSpecifier(NewII->getTokenID()))
CorrectedQuotedStr = "the keyword " + CorrectedQuotedStr;
Diag(IILoc, diag::err_unknown_typename_suggest)
<< II << CorrectedQuotedStr
<< FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
II = NewII;
} else {
NamedDecl *Result = Corrected.getCorrectionDecl();
// We found a similarly-named type or interface; suggest that.
if (!SS || !SS->isSet())
Diag(IILoc, diag::err_unknown_typename_suggest)
<< II << CorrectedQuotedStr
<< FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
else if (DeclContext *DC = computeDeclContext(*SS, false))
Diag(IILoc, diag::err_unknown_nested_typename_suggest)
<< II << DC << CorrectedQuotedStr << SS->getRange()
<< FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
llvm_unreachable("could not have corrected a typo here");
Diag(Result->getLocation(), diag::note_previous_decl)
<< CorrectedQuotedStr;
SuggestedType = getTypeName(*Result->getIdentifier(), IILoc, S, SS,
false, false, ParsedType(),
return true;
if (getLangOpts().CPlusPlus) {
// See if II is a class template that the user forgot to pass arguments to.
UnqualifiedId Name;
Name.setIdentifier(II, IILoc);
CXXScopeSpec EmptySS;
TemplateTy TemplateResult;
bool MemberOfUnknownSpecialization;
if (isTemplateName(S, SS ? *SS : EmptySS, /*hasTemplateKeyword=*/false,
Name, ParsedType(), true, TemplateResult,
MemberOfUnknownSpecialization) == TNK_Type_template) {
TemplateName TplName = TemplateResult.getAsVal<TemplateName>();
Diag(IILoc, diag::err_template_missing_args) << TplName;
if (TemplateDecl *TplDecl = TplName.getAsTemplateDecl()) {
Diag(TplDecl->getLocation(), diag::note_template_decl_here)
<< TplDecl->getTemplateParameters()->getSourceRange();
return true;
// FIXME: Should we move the logic that tries to recover from a missing tag
// (struct, union, enum) from Parser::ParseImplicitInt here, instead?
if (!SS || (!SS->isSet() && !SS->isInvalid()))
Diag(IILoc, diag::err_unknown_typename) << II;
else if (DeclContext *DC = computeDeclContext(*SS, false))
Diag(IILoc, diag::err_typename_nested_not_found)
<< II << DC << SS->getRange();
else if (isDependentScopeSpecifier(*SS)) {
unsigned DiagID = diag::err_typename_missing;
if (getLangOpts().MicrosoftMode && isMicrosoftMissingTypename(SS, S))
DiagID = diag::warn_typename_missing;
Diag(SS->getRange().getBegin(), DiagID)
<< (NestedNameSpecifier *)SS->getScopeRep() << II->getName()
<< SourceRange(SS->getRange().getBegin(), IILoc)
<< FixItHint::CreateInsertion(SS->getRange().getBegin(), "typename ");
SuggestedType = ActOnTypenameType(S, SourceLocation(),
*SS, *II, IILoc).get();
} else {
assert(SS && SS->isInvalid() &&
"Invalid scope specifier has already been diagnosed");
return true;
/// \brief Determine whether the given result set contains either a type name
/// or
static bool isResultTypeOrTemplate(LookupResult &R, const Token &NextToken) {
bool CheckTemplate = R.getSema().getLangOpts().CPlusPlus &&;
for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
if (isa<TypeDecl>(*I) || isa<ObjCInterfaceDecl>(*I))
return true;
if (CheckTemplate && isa<TemplateDecl>(*I))
return true;
return false;
static bool isTagTypeWithMissingTag(Sema &SemaRef, LookupResult &Result,
Scope *S, CXXScopeSpec &SS,
IdentifierInfo *&Name,
SourceLocation NameLoc) {
SemaRef.LookupParsedName(Result, S, &SS);
if (TagDecl *Tag = Result.getAsSingle<TagDecl>()) {
const char *TagName = 0;
const char *FixItTagName = 0;
switch (Tag->getTagKind()) {
case TTK_Class:
TagName = "class";
FixItTagName = "class ";
case TTK_Enum:
TagName = "enum";
FixItTagName = "enum ";
case TTK_Struct:
TagName = "struct";
FixItTagName = "struct ";
case TTK_Union:
TagName = "union";
FixItTagName = "union ";
SemaRef.Diag(NameLoc, diag::err_use_of_tag_name_without_tag)
<< Name << TagName << SemaRef.getLangOpts().CPlusPlus
<< FixItHint::CreateInsertion(NameLoc, FixItTagName);
LookupResult R(SemaRef, Name, NameLoc, Sema::LookupOrdinaryName);
if (SemaRef.LookupParsedName(R, S, &SS)) {
for (LookupResult::iterator I = R.begin(), IEnd = R.end();
I != IEnd; ++I)
SemaRef.Diag((*I)->getLocation(), diag::note_decl_hiding_tag_type)
<< Name << TagName;
return true;
return false;
Sema::NameClassification Sema::ClassifyName(Scope *S,
CXXScopeSpec &SS,
IdentifierInfo *&Name,
SourceLocation NameLoc,
const Token &NextToken) {
DeclarationNameInfo NameInfo(Name, NameLoc);
ObjCMethodDecl *CurMethod = getCurMethodDecl();
if ( {
BuildCXXNestedNameSpecifier(S, *Name, NameLoc, NextToken.getLocation(),
QualType(), false, SS, 0, false);
LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
LookupParsedName(Result, S, &SS, !CurMethod);
// Perform lookup for Objective-C instance variables (including automatically
// synthesized instance variables), if we're in an Objective-C method.
// FIXME: This lookup really, really needs to be folded in to the normal
// unqualified lookup mechanism.
if (!SS.isSet() && CurMethod && !isResultTypeOrTemplate(Result, NextToken)) {
ExprResult E = LookupInObjCMethod(Result, S, Name, true);
if (E.get() || E.isInvalid())
return E;
bool SecondTry = false;
bool IsFilteredTemplateName = false;
switch (Result.getResultKind()) {
case LookupResult::NotFound:
// If an unqualified-id is followed by a '(', then we have a function
// call.
if (!SS.isSet() && {
// In C++, this is an ADL-only call.
// FIXME: Reference?
if (getLangOpts().CPlusPlus)
return BuildDeclarationNameExpr(SS, Result, /*ADL=*/true);
// C90
// If the expression that precedes the parenthesized argument list in a
// function call consists solely of an identifier, and if no
// declaration is visible for this identifier, the identifier is
// implicitly declared exactly as if, in the innermost block containing
// the function call, the declaration
// extern int identifier ();
// appeared.
// We also allow this in C99 as an extension.
if (NamedDecl *D = ImplicitlyDefineFunction(NameLoc, *Name, S)) {
return BuildDeclarationNameExpr(SS, Result, /*ADL=*/false);
// In C, we first see whether there is a tag type by the same name, in
// which case it's likely that the user just forget to write "enum",
// "struct", or "union".
if (!getLangOpts().CPlusPlus && !SecondTry &&
isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
// Perform typo correction to determine if there is another name that is
// close to this name.
if (!SecondTry) {
SecondTry = true;
CorrectionCandidateCallback DefaultValidator;
// Try to limit which sets of keywords should be included in typo
// correction based on what the next token is.
DefaultValidator.WantTypeSpecifiers = || || || || ||;
DefaultValidator.WantExpressionKeywords = || || ||;
DefaultValidator.WantRemainingKeywords = || || ||;
DefaultValidator.WantCXXNamedCasts = false;
if (TypoCorrection Corrected = CorrectTypo(Result.getLookupNameInfo(),
Result.getLookupKind(), S,
&SS, DefaultValidator)) {
unsigned UnqualifiedDiag = diag::err_undeclared_var_use_suggest;
unsigned QualifiedDiag = diag::err_no_member_suggest;
std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
std::string CorrectedQuotedStr(Corrected.getQuoted(getLangOpts()));
NamedDecl *FirstDecl = Corrected.getCorrectionDecl();
NamedDecl *UnderlyingFirstDecl
= FirstDecl? FirstDecl->getUnderlyingDecl() : 0;
if (getLangOpts().CPlusPlus && &&
UnderlyingFirstDecl && isa<TemplateDecl>(UnderlyingFirstDecl)) {
UnqualifiedDiag = diag::err_no_template_suggest;
QualifiedDiag = diag::err_no_member_template_suggest;
} else if (UnderlyingFirstDecl &&
(isa<TypeDecl>(UnderlyingFirstDecl) ||
isa<ObjCInterfaceDecl>(UnderlyingFirstDecl) ||
isa<ObjCCompatibleAliasDecl>(UnderlyingFirstDecl))) {
UnqualifiedDiag = diag::err_unknown_typename_suggest;
QualifiedDiag = diag::err_unknown_nested_typename_suggest;
if (SS.isEmpty())
Diag(NameLoc, UnqualifiedDiag)
<< Name << CorrectedQuotedStr
<< FixItHint::CreateReplacement(NameLoc, CorrectedStr);
Diag(NameLoc, QualifiedDiag)
<< Name << computeDeclContext(SS, false) << CorrectedQuotedStr
<< SS.getRange()
<< FixItHint::CreateReplacement(NameLoc, CorrectedStr);
// Update the name, so that the caller has the new name.
Name = Corrected.getCorrectionAsIdentifierInfo();
// Typo correction corrected to a keyword.
if (Corrected.isKeyword())
return Corrected.getCorrectionAsIdentifierInfo();
// Also update the LookupResult...
// FIXME: This should probably go away at some point
if (FirstDecl) {
Diag(FirstDecl->getLocation(), diag::note_previous_decl)
<< CorrectedQuotedStr;
// If we found an Objective-C instance variable, let
// LookupInObjCMethod build the appropriate expression to
// reference the ivar.
// FIXME: This is a gross hack.
if (ObjCIvarDecl *Ivar = Result.getAsSingle<ObjCIvarDecl>()) {
ExprResult E(LookupInObjCMethod(Result, S, Ivar->getIdentifier()));
return move(E);
goto Corrected;
// We failed to correct; just fall through and let the parser deal with it.
return NameClassification::Unknown();
case LookupResult::NotFoundInCurrentInstantiation: {
// We performed name lookup into the current instantiation, and there were
// dependent bases, so we treat this result the same way as any other
// dependent nested-name-specifier.
// C++ [temp.res]p2:
// A name used in a template declaration or definition and that is
// dependent on a template-parameter is assumed not to name a type
// unless the applicable name lookup finds a type name or the name is
// qualified by the keyword typename.
// FIXME: If the next token is '<', we might want to ask the parser to
// perform some heroics to see if we actually have a
// template-argument-list, which would indicate a missing 'template'
// keyword here.
return BuildDependentDeclRefExpr(SS, /*TemplateKWLoc=*/SourceLocation(),
NameInfo, /*TemplateArgs=*/0);
case LookupResult::Found:
case LookupResult::FoundOverloaded:
case LookupResult::FoundUnresolvedValue:
case LookupResult::Ambiguous:
if (getLangOpts().CPlusPlus && &&
hasAnyAcceptableTemplateNames(Result)) {
// C++ [temp.local]p3:
// A lookup that finds an injected-class-name (10.2) can result in an
// ambiguity in certain cases (for example, if it is found in more than
// one base class). If all of the injected-class-names that are found
// refer to specializations of the same class template, and if the name
// is followed by a template-argument-list, the reference refers to the
// class template itself and not a specialization thereof, and is not
// ambiguous.
// This filtering can make an ambiguous result into an unambiguous one,
// so try again after filtering out template names.
if (!Result.isAmbiguous()) {
IsFilteredTemplateName = true;
// Diagnose the ambiguity and return an error.
return NameClassification::Error();
if (getLangOpts().CPlusPlus && &&
(IsFilteredTemplateName || hasAnyAcceptableTemplateNames(Result))) {
// C++ [temp.names]p3:
// After name lookup (3.4) finds that a name is a template-name or that
// an operator-function-id or a literal- operator-id refers to a set of
// overloaded functions any member of which is a function template if
// this is followed by a <, the < is always taken as the delimiter of a
// template-argument-list and never as the less-than operator.
if (!IsFilteredTemplateName)
if (!Result.empty()) {
bool IsFunctionTemplate;
TemplateName Template;
if (Result.end() - Result.begin() > 1) {
IsFunctionTemplate = true;
Template = Context.getOverloadedTemplateName(Result.begin(),
} else {
TemplateDecl *TD
= cast<TemplateDecl>((*Result.begin())->getUnderlyingDecl());
IsFunctionTemplate = isa<FunctionTemplateDecl>(TD);
if (SS.isSet() && !SS.isInvalid())
Template = Context.getQualifiedTemplateName(SS.getScopeRep(),
Template = TemplateName(TD);
if (IsFunctionTemplate) {
// Function templates always go through overload resolution, at which
// point we'll perform the various checks (e.g., accessibility) we need
// to based on which function we selected.
return NameClassification::FunctionTemplate(Template);
return NameClassification::TypeTemplate(Template);
NamedDecl *FirstDecl = (*Result.begin())->getUnderlyingDecl();
if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
DiagnoseUseOfDecl(Type, NameLoc);
QualType T = Context.getTypeDeclType(Type);
return ParsedType::make(T);
ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(FirstDecl);
if (!Class) {
// FIXME: It's unfortunate that we don't have a Type node for handling this.
if (ObjCCompatibleAliasDecl *Alias
= dyn_cast<ObjCCompatibleAliasDecl>(FirstDecl))
Class = Alias->getClassInterface();
if (Class) {
DiagnoseUseOfDecl(Class, NameLoc);
if ( {
// Interface. <something> is parsed as a property reference expression.
// Just return "unknown" as a fall-through for now.
return NameClassification::Unknown();
QualType T = Context.getObjCInterfaceType(Class);
return ParsedType::make(T);
// Check for a tag type hidden by a non-type decl in a few cases where it
// seems likely a type is wanted instead of the non-type that was found.
if (!getLangOpts().ObjC1 && FirstDecl && !isa<ClassTemplateDecl>(FirstDecl) &&
!isa<TypeAliasTemplateDecl>(FirstDecl)) {
bool NextIsOp = ||;
if (( ||
(NextIsOp && FirstDecl->isFunctionOrFunctionTemplate())) &&
isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
FirstDecl = (*Result.begin())->getUnderlyingDecl();
if (TypeDecl *Type = dyn_cast<TypeDecl>(FirstDecl)) {
DiagnoseUseOfDecl(Type, NameLoc);
QualType T = Context.getTypeDeclType(Type);
return ParsedType::make(T);
if (!Result.empty() && (*Result.begin())->isCXXClassMember())
return BuildPossibleImplicitMemberExpr(SS, SourceLocation(), Result, 0);
bool ADL = UseArgumentDependentLookup(SS, Result,;
return BuildDeclarationNameExpr(SS, Result, ADL);
// Determines the context to return to after temporarily entering a
// context. This depends in an unnecessarily complicated way on the
// exact ordering of callbacks from the parser.
DeclContext *Sema::getContainingDC(DeclContext *DC) {
// Functions defined inline within classes aren't parsed until we've
// finished parsing the top-level class, so the top-level class is
// the context we'll need to return to.
if (isa<FunctionDecl>(DC)) {
DC = DC->getLexicalParent();
// A function not defined within a class will always return to its
// lexical context.
if (!isa<CXXRecordDecl>(DC))
return DC;
// A C++ inline method/friend is parsed *after* the topmost class
// it was declared in is fully parsed ("complete"); the topmost
// class is the context we need to return to.
while (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC->getLexicalParent()))
DC = RD;
// Return the declaration context of the topmost class the inline method is
// declared in.
return DC;
return DC->getLexicalParent();
void Sema::PushDeclContext(Scope *S, DeclContext *DC) {
assert(getContainingDC(DC) == CurContext &&
"The next DeclContext should be lexically contained in the current one.");
CurContext = DC;
void Sema::PopDeclContext() {
assert(CurContext && "DeclContext imbalance!");
CurContext = getContainingDC(CurContext);
assert(CurContext && "Popped translation unit!");
/// EnterDeclaratorContext - Used when we must lookup names in the context
/// of a declarator's nested name specifier.
void Sema::EnterDeclaratorContext(Scope *S, DeclContext *DC) {
// C++0x [basic.lookup.unqual]p13:
// A name used in the definition of a static data member of class
// X (after the qualified-id of the static member) is looked up as
// if the name was used in a member function of X.
// C++0x [basic.lookup.unqual]p14:
// If a variable member of a namespace is defined outside of the
// scope of its namespace then any name used in the definition of
// the variable member (after the declarator-id) is looked up as
// if the definition of the variable member occurred in its
// namespace.
// Both of these imply that we should push a scope whose context
// is the semantic context of the declaration. We can't use
// PushDeclContext here because that context is not necessarily
// lexically contained in the current context. Fortunately,
// the containing scope should have the appropriate information.
assert(!S->getEntity() && "scope already has entity");
#ifndef NDEBUG
Scope *Ancestor = S->getParent();
while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
assert(Ancestor->getEntity() == CurContext && "ancestor context mismatch");
CurContext = DC;
void Sema::ExitDeclaratorContext(Scope *S) {
assert(S->getEntity() == CurContext && "Context imbalance!");
// Switch back to the lexical context. The safety of this is
// enforced by an assert in EnterDeclaratorContext.
Scope *Ancestor = S->getParent();
while (!Ancestor->getEntity()) Ancestor = Ancestor->getParent();
CurContext = (DeclContext*) Ancestor->getEntity();
// We don't need to do anything with the scope, which is going to
// disappear.
void Sema::ActOnReenterFunctionContext(Scope* S, Decl *D) {
FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
if (FunctionTemplateDecl *TFD = dyn_cast_or_null<FunctionTemplateDecl>(D)) {
// We assume that the caller has already called
// ActOnReenterTemplateScope
FD = TFD->getTemplatedDecl();
if (!FD)
// Same implementation as PushDeclContext, but enters the context
// from the lexical parent, rather than the top-level class.
assert(CurContext == FD->getLexicalParent() &&
"The next DeclContext should be lexically contained in the current one.");
CurContext = FD;
for (unsigned P = 0, NumParams = FD->getNumParams(); P < NumParams; ++P) {
ParmVarDecl *Param = FD->getParamDecl(P);
// If the parameter has an identifier, then add it to the scope
if (Param->getIdentifier()) {
void Sema::ActOnExitFunctionContext() {
// Same implementation as PopDeclContext, but returns to the lexical parent,
// rather than the top-level class.
assert(CurContext && "DeclContext imbalance!");
CurContext = CurContext->getLexicalParent();
assert(CurContext && "Popped translation unit!");
/// \brief Determine whether we allow overloading of the function
/// PrevDecl with another declaration.
/// This routine determines whether overloading is possible, not
/// whether some new function is actually an overload. It will return
/// true in C++ (where we can always provide overloads) or, as an
/// extension, in C when the previous function is already an
/// overloaded function declaration or has the "overloadable"
/// attribute.
static bool AllowOverloadingOfFunction(LookupResult &Previous,
ASTContext &Context) {
if (Context.getLangOpts().CPlusPlus)
return true;
if (Previous.getResultKind() == LookupResult::FoundOverloaded)
return true;
return (Previous.getResultKind() == LookupResult::Found
&& Previous.getFoundDecl()->hasAttr<OverloadableAttr>());
/// Add this decl to the scope shadowed decl chains.
void Sema::PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext) {
// Move up the scope chain until we find the nearest enclosing
// non-transparent context. The declaration will be introduced into this
// scope.
while (S->getEntity() &&
((DeclContext *)S->getEntity())->isTransparentContext())
S = S->getParent();
// Add scoped declarations into their context, so that they can be
// found later. Declarations without a context won't be inserted
// into any context.
if (AddToContext)
// Out-of-line definitions shouldn't be pushed into scope in C++.
// Out-of-line variable and function definitions shouldn't even in C.
if ((getLangOpts().CPlusPlus || isa<VarDecl>(D) || isa<FunctionDecl>(D)) &&
D->isOutOfLine() &&
// Template instantiations should also not be pushed into scope.
if (isa<FunctionDecl>(D) &&
// If this replaces anything in the current scope,
IdentifierResolver::iterator I = IdResolver.begin(D->getDeclName()),
IEnd = IdResolver.end();
for (; I != IEnd; ++I) {
if (S->isDeclScope(*I) && D->declarationReplaces(*I)) {
// Should only need to replace one decl.
if (isa<LabelDecl>(D) && !cast<LabelDecl>(D)->isGnuLocal()) {
// Implicitly-generated labels may end up getting generated in an order that
// isn't strictly lexical, which breaks name lookup. Be careful to insert
// the label at the appropriate place in the identifier chain.
for (I = IdResolver.begin(D->getDeclName()); I != IEnd; ++I) {
DeclContext *IDC = (*I)->getLexicalDeclContext()->getRedeclContext();
if (IDC == CurContext) {
if (!S->isDeclScope(*I))
} else if (IDC->Encloses(CurContext))
IdResolver.InsertDeclAfter(I, D);
} else {
void Sema::pushExternalDeclIntoScope(NamedDecl *D, DeclarationName Name) {
if (IdResolver.tryAddTopLevelDecl(D, Name) && TUScope)
bool Sema::isDeclInScope(NamedDecl *&D, DeclContext *Ctx, Scope *S,
bool ExplicitInstantiationOrSpecialization) {
return IdResolver.isDeclInScope(D, Ctx, Context, S,
Scope *Sema::getScopeForDeclContext(Scope *S, DeclContext *DC) {
DeclContext *TargetDC = DC->getPrimaryContext();
do {
if (DeclContext *ScopeDC = (DeclContext*) S->getEntity())
if (ScopeDC->getPrimaryContext() == TargetDC)
return S;
} while ((S = S->getParent()));
return 0;
static bool isOutOfScopePreviousDeclaration(NamedDecl *,
/// Filters out lookup results that don't fall within the given scope
/// as determined by isDeclInScope.
void Sema::FilterLookupForScope(LookupResult &R,
DeclContext *Ctx, Scope *S,
bool ConsiderLinkage,
bool ExplicitInstantiationOrSpecialization) {
LookupResult::Filter F = R.makeFilter();
while (F.hasNext()) {
NamedDecl *D =;
if (isDeclInScope(D, Ctx, S, ExplicitInstantiationOrSpecialization))
if (ConsiderLinkage &&
isOutOfScopePreviousDeclaration(D, Ctx, Context))
static bool isUsingDecl(NamedDecl *D) {
return isa<UsingShadowDecl>(D) ||
isa<UnresolvedUsingTypenameDecl>(D) ||
/// Removes using shadow declarations from the lookup results.
static void RemoveUsingDecls(LookupResult &R) {
LookupResult::Filter F = R.makeFilter();
while (F.hasNext())
if (isUsingDecl(
/// \brief Check for this common pattern:
/// @code
/// class S {
/// S(const S&); // DO NOT IMPLEMENT
/// void operator=(const S&); // DO NOT IMPLEMENT
/// };
/// @endcode
static bool IsDisallowedCopyOrAssign(const CXXMethodDecl *D) {
// FIXME: Should check for private access too but access is set after we get
// the decl here.
if (D->doesThisDeclarationHaveABody())
return false;
if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(D))
return CD->isCopyConstructor();
if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
return Method->isCopyAssignmentOperator();
return false;
bool Sema::ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const {
if (D->isInvalidDecl() || D->isUsed() || D->hasAttr<UnusedAttr>())
return false;
// Ignore class templates.
if (D->getDeclContext()->isDependentContext() ||
return false;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
return false;
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
if (MD->isVirtual() || IsDisallowedCopyOrAssign(MD))
return false;
} else {
// 'static inline' functions are used in headers; don't warn.
if (FD->getStorageClass() == SC_Static &&
return false;
if (FD->doesThisDeclarationHaveABody() &&
return false;
} else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (!VD->isFileVarDecl() ||
VD->getType().isConstant(Context) ||
return false;
if (VD->isStaticDataMember() &&
VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
return false;
} else {
return false;
// Only warn for unused decls internal to the translation unit.
if (D->getLinkage() == ExternalLinkage)
return false;
return true;
void Sema::MarkUnusedFileScopedDecl(const DeclaratorDecl *D) {
if (!D)
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
const FunctionDecl *First = FD->getFirstDeclaration();
if (FD != First && ShouldWarnIfUnusedFileScopedDecl(First))
return; // First should already be in the vector.
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
const VarDecl *First = VD->getFirstDeclaration();
if (VD != First && ShouldWarnIfUnusedFileScopedDecl(First))
return; // First should already be in the vector.
if (ShouldWarnIfUnusedFileScopedDecl(D))
static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) {
if (D->isInvalidDecl())
return false;
if (D->isReferenced() || D->isUsed() || D->hasAttr<UnusedAttr>())
return false;
if (isa<LabelDecl>(D))
return true;
// White-list anything that isn't a local variable.
if (!isa<VarDecl>(D) || isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D) ||
return false;
// Types of valid local variables should be complete, so this should succeed.
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
// White-list anything with an __attribute__((unused)) type.
QualType Ty = VD->getType();
// Only look at the outermost level of typedef.
if (const TypedefType *TT = dyn_cast<TypedefType>(Ty)) {
if (TT->getDecl()->hasAttr<UnusedAttr>())
return false;
// If we failed to complete the type for some reason, or if the type is
// dependent, don't diagnose the variable.
if (Ty->isIncompleteType() || Ty->isDependentType())
return false;
if (const TagType *TT = Ty->getAs<TagType>()) {
const TagDecl *Tag = TT->getDecl();
if (Tag->hasAttr<UnusedAttr>())
return false;
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Tag)) {
if (!RD->hasTrivialDestructor())
return false;
if (const Expr *Init = VD->getInit()) {
const CXXConstructExpr *Construct =
if (Construct && !Construct->isElidable()) {
CXXConstructorDecl *CD = Construct->getConstructor();
if (!CD->isTrivial())
return false;
// TODO: __attribute__((unused)) templates?
return true;
static void GenerateFixForUnusedDecl(const NamedDecl *D, ASTContext &Ctx,
FixItHint &Hint) {
if (isa<LabelDecl>(D)) {
SourceLocation AfterColon = Lexer::findLocationAfterToken(D->getLocEnd(),
tok::colon, Ctx.getSourceManager(), Ctx.getLangOpts(), true);
if (AfterColon.isInvalid())
Hint = FixItHint::CreateRemoval(CharSourceRange::
getCharRange(D->getLocStart(), AfterColon));
/// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
/// unless they are marked attr(unused).
void Sema::DiagnoseUnusedDecl(const NamedDecl *D) {
FixItHint Hint;
if (!ShouldDiagnoseUnusedDecl(D))
GenerateFixForUnusedDecl(D, Context, Hint);
unsigned DiagID;
if (isa<VarDecl>(D) && cast<VarDecl>(D)->isExceptionVariable())
DiagID = diag::warn_unused_exception_param;
else if (isa<LabelDecl>(D))
DiagID = diag::warn_unused_label;
DiagID = diag::warn_unused_variable;
Diag(D->getLocation(), DiagID) << D->getDeclName() << Hint;
static void CheckPoppedLabel(LabelDecl *L, Sema &S) {
// Verify that we have no forward references left. If so, there was a goto
// or address of a label taken, but no definition of it. Label fwd
// definitions are indicated with a null substmt.
if (L->getStmt() == 0)
S.Diag(L->getLocation(), diag::err_undeclared_label_use) <<L->getDeclName();
void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
if (S->decl_empty()) return;
assert((S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) &&
"Scope shouldn't contain decls!");
for (Scope::decl_iterator I = S->decl_begin(), E = S->decl_end();
I != E; ++I) {
Decl *TmpD = (*I);
assert(TmpD && "This decl didn't get pushed??");
assert(isa<NamedDecl>(TmpD) && "Decl isn't NamedDecl?");
NamedDecl *D = cast<NamedDecl>(TmpD);
if (!D->getDeclName()) continue;
// Diagnose unused variables in this scope.
if (!S->hasErrorOccurred())
// If this was a forward reference to a label, verify it was defined.
if (LabelDecl *LD = dyn_cast<LabelDecl>(D))
CheckPoppedLabel(LD, *this);
// Remove this name from our lexical scope.
void Sema::ActOnStartFunctionDeclarator() {
void Sema::ActOnEndFunctionDeclarator() {
/// \brief Look for an Objective-C class in the translation unit.
/// \param Id The name of the Objective-C class we're looking for. If
/// typo-correction fixes this name, the Id will be updated
/// to the fixed name.
/// \param IdLoc The location of the name in the translation unit.
/// \param DoTypoCorrection If true, this routine will attempt typo correction
/// if there is no class with the given name.
/// \returns The declaration of the named Objective-C class, or NULL if the
/// class could not be found.
ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(IdentifierInfo *&Id,
SourceLocation IdLoc,
bool DoTypoCorrection) {
// The third "scope" argument is 0 since we aren't enabling lazy built-in
// creation from this context.
NamedDecl *IDecl = LookupSingleName(TUScope, Id, IdLoc, LookupOrdinaryName);
if (!IDecl && DoTypoCorrection) {
// Perform typo correction at the given location, but only if we
// find an Objective-C class name.
DeclFilterCCC<ObjCInterfaceDecl> Validator;
if (TypoCorrection C = CorrectTypo(DeclarationNameInfo(Id, IdLoc),
LookupOrdinaryName, TUScope, NULL,
Validator)) {
IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>();
Diag(IdLoc, diag::err_undef_interface_suggest)
<< Id << IDecl->getDeclName()
<< FixItHint::CreateReplacement(IdLoc, IDecl->getNameAsString());
Diag(IDecl->getLocation(), diag::note_previous_decl)
<< IDecl->getDeclName();
Id = IDecl->getIdentifier();
ObjCInterfaceDecl *Def = dyn_cast_or_null<ObjCInterfaceDecl>(IDecl);
// This routine must always return a class definition, if any.
if (Def && Def->getDefinition())
Def = Def->getDefinition();
return Def;
/// getNonFieldDeclScope - Retrieves the innermost scope, starting
/// from S, where a non-field would be declared. This routine copes
/// with the difference between C and C++ scoping rules in structs and
/// unions. For example, the following code is well-formed in C but
/// ill-formed in C++:
/// @code
/// struct S6 {
/// enum { BAR } e;
/// };
/// void test_S6() {
/// struct S6 a;
/// a.e = BAR;
/// }
/// @endcode
/// For the declaration of BAR, this routine will return a different
/// scope. The scope S will be the scope of the unnamed enumeration
/// within S6. In C++, this routine will return the scope associated
/// with S6, because the enumeration's scope is a transparent
/// context but structures can contain non-field names. In C, this
/// routine will return the translation unit scope, since the
/// enumeration's scope is a transparent context and structures cannot
/// contain non-field names.
Scope *Sema::getNonFieldDeclScope(Scope *S) {
while (((S->getFlags() & Scope::DeclScope) == 0) ||
(S->getEntity() &&
((DeclContext *)S->getEntity())->isTransparentContext()) ||
(S->isClassScope() && !getLangOpts().CPlusPlus))
S = S->getParent();
return S;
/// LazilyCreateBuiltin - The specified Builtin-ID was first used at
/// file scope. lazily create a decl for it. ForRedeclaration is true
/// if we're creating this built-in in anticipation of redeclaring the
/// built-in.
NamedDecl *Sema::LazilyCreateBuiltin(IdentifierInfo *II, unsigned bid,
Scope *S, bool ForRedeclaration,
SourceLocation Loc) {
Builtin::ID BID = (Builtin::ID)bid;
ASTContext::GetBuiltinTypeError Error;
QualType R = Context.GetBuiltinType(BID, Error);
switch (Error) {
case ASTContext::GE_None:
// Okay
case ASTContext::GE_Missing_stdio:
if (ForRedeclaration)
Diag(Loc, diag::warn_implicit_decl_requires_stdio)
<< Context.BuiltinInfo.GetName(BID);
return 0;
case ASTContext::GE_Missing_setjmp:
if (ForRedeclaration)
Diag(Loc, diag::warn_implicit_decl_requires_setjmp)
<< Context.BuiltinInfo.GetName(BID);
return 0;
case ASTContext::GE_Missing_ucontext:
if (ForRedeclaration)
Diag(Loc, diag::warn_implicit_decl_requires_ucontext)
<< Context.BuiltinInfo.GetName(BID);
return 0;
if (!ForRedeclaration && Context.BuiltinInfo.isPredefinedLibFunction(BID)) {
Diag(Loc, diag::ext_implicit_lib_function_decl)
<< Context.BuiltinInfo.GetName(BID)
<< R;
if (Context.BuiltinInfo.getHeaderName(BID) &&
Diags.getDiagnosticLevel(diag::ext_implicit_lib_function_decl, Loc)
!= DiagnosticsEngine::Ignored)
Diag(Loc, diag::note_please_include_header)
<< Context.BuiltinInfo.getHeaderName(BID)
<< Context.BuiltinInfo.GetName(BID);
FunctionDecl *New = FunctionDecl::Create(Context,
Loc, Loc, II, R, /*TInfo=*/0,
SC_None, false,
// Create Decl objects for each parameter, adding them to the
// FunctionDecl.
if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(R)) {
SmallVector<ParmVarDecl*, 16> Params;
for (unsigned i = 0, e = FT->getNumArgs(); i != e; ++i) {
ParmVarDecl *parm =
ParmVarDecl::Create(Context, New, SourceLocation(),
SourceLocation(), 0,
FT->getArgType(i), /*TInfo=*/0,
SC_None, SC_None, 0);
parm->setScopeInfo(0, i);
// TUScope is the translation-unit scope to insert this function into.
// FIXME: This is hideous. We need to teach PushOnScopeChains to
// relate Scopes to DeclContexts, and probably eliminate CurContext
// entirely, but we're not there yet.
DeclContext *SavedContext = CurContext;
CurContext = Context.getTranslationUnitDecl();
PushOnScopeChains(New, TUScope);
CurContext = SavedContext;
return New;
bool Sema::isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New) {
QualType OldType;
if (TypedefNameDecl *OldTypedef = dyn_cast<TypedefNameDecl>(Old))
OldType = OldTypedef->getUnderlyingType();
OldType = Context.getTypeDeclType(Old);
QualType NewType = New->getUnderlyingType();
if (NewType->isVariablyModifiedType()) {
// Must not redefine a typedef with a variably-modified type.
int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
Diag(New->getLocation(), diag::err_redefinition_variably_modified_typedef)
<< Kind << NewType;
if (Old->getLocation().isValid())
Diag(Old->getLocation(), diag::note_previous_definition);
return true;
if (OldType != NewType &&
!OldType->isDependentType() &&
!NewType->isDependentType() &&
!Context.hasSameType(OldType, NewType)) {
int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
Diag(New->getLocation(), diag::err_redefinition_different_typedef)
<< Kind << NewType << OldType;
if (Old->getLocation().isValid())
Diag(Old->getLocation(), diag::note_previous_definition);
return true;
return false;
/// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
/// same name and scope as a previous declaration 'Old'. Figure out
/// how to resolve this situation, merging decls or emitting
/// diagnostics as appropriate. If there was an error, set New to be invalid.
void Sema::MergeTypedefNameDecl(TypedefNameDecl *New, LookupResult &OldDecls) {
// If the new decl is known invalid already, don't bother doing any
// merging checks.
if (New->isInvalidDecl()) return;
// Allow multiple definitions for ObjC built-in typedefs.
// FIXME: Verify the underlying types are equivalent!
if (getLangOpts().ObjC1) {
const IdentifierInfo *TypeID = New->getIdentifier();
switch (TypeID->getLength()) {
default: break;
case 2:
if (!TypeID->isStr("id"))
QualType T = New->getUnderlyingType();
if (!T->isPointerType())
if (!T->isVoidPointerType()) {
QualType PT = T->getAs<PointerType>()->getPointeeType();
if (!PT->isStructureType())
// Install the built-in type for 'id', ignoring the current definition.
case 5:
if (!TypeID->isStr("Class"))
// Install the built-in type for 'Class', ignoring the current definition.
case 3:
if (!TypeID->isStr("SEL"))
// Install the built-in type for 'SEL', ignoring the current definition.
// Fall through - the typedef name was not a builtin type.
// Verify the old decl was also a type.
TypeDecl *Old = OldDecls.getAsSingle<TypeDecl>();
if (!Old) {
Diag(New->getLocation(), diag::err_redefinition_different_kind)
<< New->getDeclName();
NamedDecl *OldD = OldDecls.getRepresentativeDecl();
if (OldD->getLocation().isValid())
Diag(OldD->getLocation(), diag::note_previous_definition);
return New->setInvalidDecl();
// If the old declaration is invalid, just give up here.
if (Old->isInvalidDecl())
return New->setInvalidDecl();
// If the typedef types are not identical, reject them in all languages and
// with any extensions enabled.
if (isIncompatibleTypedef(Old, New))
// The types match. Link up the redeclaration chain if the old
// declaration was a typedef.
if (TypedefNameDecl *Typedef = dyn_cast<TypedefNameDecl>(Old))
if (getLangOpts().MicrosoftExt)
if (getLangOpts().CPlusPlus) {
// C++ [dcl.typedef]p2:
// In a given non-class scope, a typedef specifier can be used to
// redefine the name of any type declared in that scope to refer
// to the type to which it already refers.
if (!isa<CXXRecordDecl>(CurContext))
// C++0x [dcl.typedef]p4:
// In a given class scope, a typedef specifier can be used to redefine
// any class-name declared in that scope that is not also a typedef-name
// to refer to the type to which it already refers.
// This wording came in via DR424, which was a correction to the
// wording in DR56, which accidentally banned code like:
// struct S {
// typedef struct A { } A;
// };
// in the C++03 standard. We implement the C++0x semantics, which
// allow the above but disallow
// struct S {
// typedef int I;
// typedef int I;
// };
// since that was the intent of DR56.
if (!isa<TypedefNameDecl>(Old))
Diag(New->getLocation(), diag::err_redefinition)
<< New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
return New->setInvalidDecl();
// Modules always permit redefinition of typedefs, as does C11.
if (getLangOpts().Modules || getLangOpts().C11)
// If we have a redefinition of a typedef in C, emit a warning. This warning
// is normally mapped to an error, but can be controlled with
// -Wtypedef-redefinition. If either the original or the redefinition is
// in a system header, don't emit this for compatibility with GCC.
if (getDiagnostics().getSuppressSystemWarnings() &&
(Context.getSourceManager().isInSystemHeader(Old->getLocation()) ||
Diag(New->getLocation(), diag::warn_redefinition_of_typedef)
<< New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
/// DeclhasAttr - returns true if decl Declaration already has the target
/// attribute.
static bool
DeclHasAttr(const Decl *D, const Attr *A) {
// There can be multiple AvailabilityAttr in a Decl. Make sure we copy
// all of them. It is mergeAvailabilityAttr in SemaDeclAttr.cpp that is
// responsible for making sure they are consistent.
const AvailabilityAttr *AA = dyn_cast<AvailabilityAttr>(A);
if (AA)
return false;
const OwnershipAttr *OA = dyn_cast<OwnershipAttr>(A);
const AnnotateAttr *Ann = dyn_cast<AnnotateAttr>(A);
for (Decl::attr_iterator i = D->attr_begin(), e = D->attr_end(); i != e; ++i)
if ((*i)->getKind() == A->getKind()) {
if (Ann) {
if (Ann->getAnnotation() == cast<AnnotateAttr>(*i)->getAnnotation())
return true;
// FIXME: Don't hardcode this check
if (OA && isa<OwnershipAttr>(*i))
return OA->getOwnKind() == cast<OwnershipAttr>(*i)->getOwnKind();
return true;
return false;
bool Sema::mergeDeclAttribute(Decl *D, InheritableAttr *Attr) {
InheritableAttr *NewAttr = NULL;
if (AvailabilityAttr *AA = dyn_cast<AvailabilityAttr>(Attr))
NewAttr = mergeAvailabilityAttr(D, AA->getRange(), AA->getPlatform(),
AA->getIntroduced(), AA->getDeprecated(),
AA->getObsoleted(), AA->getUnavailable(),
else if (VisibilityAttr *VA = dyn_cast<VisibilityAttr>(Attr))
NewAttr = mergeVisibilityAttr(D, VA->getRange(), VA->getVisibility());
else if (DLLImportAttr *ImportA = dyn_cast<DLLImportAttr>(Attr))
NewAttr = mergeDLLImportAttr(D, ImportA->getRange());
else if (DLLExportAttr *ExportA = dyn_cast<DLLExportAttr>(Attr))
NewAttr = mergeDLLExportAttr(D, ExportA->getRange());
else if (FormatAttr *FA = dyn_cast<FormatAttr>(Attr))
NewAttr = mergeFormatAttr(D, FA->getRange(), FA->getType(),
FA->getFormatIdx(), FA->getFirstArg());
else if (SectionAttr *SA = dyn_cast<SectionAttr>(Attr))
NewAttr = mergeSectionAttr(D, SA->getRange(), SA->getName());
else if (!DeclHasAttr(D, Attr))
NewAttr = cast<InheritableAttr>(Attr->clone(Context));
if (NewAttr) {
return true;
return false;
static const Decl *getDefinition(const Decl *D) {
if (const TagDecl *TD = dyn_cast<TagDecl>(D))
return TD->getDefinition();
if (const VarDecl *VD = dyn_cast<VarDecl>(D))
return VD->getDefinition();
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
const FunctionDecl* Def;
if (FD->hasBody(Def))
return Def;
return NULL;
static bool hasAttribute(const Decl *D, attr::Kind Kind) {
for (Decl::attr_iterator I = D->attr_begin(), E = D->attr_end();
I != E; ++I) {
Attr *Attribute = *I;
if (Attribute->getKind() == Kind)
return true;
return false;
/// checkNewAttributesAfterDef - If we already have a definition, check that
/// there are no new attributes in this declaration.
static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
if (!New->hasAttrs())
const Decl *Def = getDefinition(Old);
if (!Def || Def == New)
AttrVec &NewAttributes = New->getAttrs();
for (unsigned I = 0, E = NewAttributes.size(); I != E;) {
const Attr *NewAttribute = NewAttributes[I];
if (hasAttribute(Def, NewAttribute->getKind())) {
continue; // regular attr merging will take care of validating this.
S.Diag(Def->getLocation(), diag::note_previous_definition);
NewAttributes.erase(NewAttributes.begin() + I);
/// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
void Sema::mergeDeclAttributes(Decl *New, Decl *Old,
bool MergeDeprecation) {
// attributes declared post-definition are currently ignored
checkNewAttributesAfterDef(*this, New, Old);
if (!Old->hasAttrs())
bool foundAny = New->hasAttrs();
// Ensure that any moving of objects within the allocated map is done before
// we process them.
if (!foundAny) New->setAttrs(AttrVec());
for (specific_attr_iterator<InheritableAttr>
i = Old->specific_attr_begin<InheritableAttr>(),
e = Old->specific_attr_end<InheritableAttr>();
i != e; ++i) {
// Ignore deprecated/unavailable/availability attributes if requested.
if (!MergeDeprecation &&
(isa<DeprecatedAttr>(*i) ||
isa<UnavailableAttr>(*i) ||
if (mergeDeclAttribute(New, *i))
foundAny = true;
if (!foundAny) New->dropAttrs();
/// mergeParamDeclAttributes - Copy attributes from the old parameter
/// to the new one.
static void mergeParamDeclAttributes(ParmVarDecl *newDecl,
const ParmVarDecl *oldDecl,
ASTContext &C) {
if (!oldDecl->hasAttrs())
bool foundAny = newDecl->hasAttrs();
// Ensure that any moving of objects within the allocated map is
// done before we process them.
if (!foundAny) newDecl->setAttrs(AttrVec());
for (specific_attr_iterator<InheritableParamAttr>
i = oldDecl->specific_attr_begin<InheritableParamAttr>(),
e = oldDecl->specific_attr_end<InheritableParamAttr>(); i != e; ++i) {
if (!DeclHasAttr(newDecl, *i)) {
InheritableAttr *newAttr = cast<InheritableParamAttr>((*i)->clone(C));
foundAny = true;
if (!foundAny) newDecl->dropAttrs();
namespace {
/// Used in MergeFunctionDecl to keep track of function parameters in
/// C.
struct GNUCompatibleParamWarning {
ParmVarDecl *OldParm;
ParmVarDecl *NewParm;
QualType PromotedType;
/// getSpecialMember - get the special member enum for a method.
Sema::CXXSpecialMember Sema::getSpecialMember(const CXXMethodDecl *MD) {
if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
if (Ctor->isDefaultConstructor())
return Sema::CXXDefaultConstructor;
if (Ctor->isCopyConstructor())
return Sema::CXXCopyConstructor;
if (Ctor->isMoveConstructor())
return Sema::CXXMoveConstructor;
} else if (isa<CXXDestructorDecl>(MD)) {
return Sema::CXXDestructor;
} else if (MD->isCopyAssignmentOperator()) {
return Sema::CXXCopyAssignment;
} else if (MD->isMoveAssignmentOperator()) {
return Sema::CXXMoveAssignment;
return Sema::CXXInvalid;
/// canRedefineFunction - checks if a function can be redefined. Currently,
/// only extern inline functions can be redefined, and even then only in
/// GNU89 mode.
static bool canRedefineFunction(const FunctionDecl *FD,
const LangOptions& LangOpts) {
return ((FD->hasAttr<GNUInlineAttr>() || LangOpts.GNUInline) &&
!LangOpts.CPlusPlus &&
FD->isInlineSpecified() &&
FD->getStorageClass() == SC_Extern);
/// MergeFunctionDecl - We just parsed a function 'New' from
/// declarator D which has the same name and scope as a previous
/// declaration 'Old'. Figure out how to resolve this situation,
/// merging decls or emitting diagnostics as appropriate.
/// In C++, New and Old must be declarations that are not
/// overloaded. Use IsOverload to determine whether New and Old are
/// overloaded, and to select the Old declaration that New should be
/// merged with.
/// Returns true if there was an error, false otherwise.
bool Sema::MergeFunctionDecl(FunctionDecl *New, Decl *OldD, Scope *S) {
// Verify the old decl was also a function.
FunctionDecl *Old = 0;
if (FunctionTemplateDecl *OldFunctionTemplate
= dyn_cast<FunctionTemplateDecl>(OldD))
Old = OldFunctionTemplate->getTemplatedDecl();
Old = dyn_cast<FunctionDecl>(OldD);
if (!Old) {
if (UsingShadowDecl *Shadow = dyn_cast<UsingShadowDecl>(OldD)) {
Diag(New->getLocation(), diag::err_using_decl_conflict_reverse);
diag::note_using_decl) << 0;
return true;
Diag(New->getLocation(), diag::err_redefinition_different_kind)
<< New->getDeclName();
Diag(OldD->getLocation(), diag::note_previous_definition);
return true;
// Determine whether the previous declaration was a definition,
// implicit declaration, or a declaration.
diag::kind PrevDiag;
if (Old->isThisDeclarationADefinition())
PrevDiag = diag::note_previous_definition;
else if (Old->isImplicit())
PrevDiag = diag::note_previous_implicit_declaration;
PrevDiag = diag::note_previous_declaration;
QualType OldQType = Context.getCanonicalType(Old->getType());
QualType NewQType = Context.getCanonicalType(New->getType());
// Don't complain about this if we're in GNU89 mode and the old function
// is an extern inline function.
if (!isa<CXXMethodDecl>(New) && !isa<CXXMethodDecl>(Old) &&
New->getStorageClass() == SC_Static &&
Old->getStorageClass() != SC_Static &&
!canRedefineFunction(Old, getLangOpts())) {
if (getLangOpts().MicrosoftExt) {
Diag(New->getLocation(), diag::warn_static_non_static) << New;
Diag(Old->getLocation(), PrevDiag);
} else {
Diag(New->getLocation(), diag::err_static_non_static) << New;
Diag(Old->getLocation(), PrevDiag);
return true;
// If a function is first declared with a calling convention, but is
// later declared or defined without one, the second decl assumes the
// calling convention of the first.
// For the new decl, we have to look at the NON-canonical type to tell the
// difference between a function that really doesn't have a calling
// convention and one that is declared cdecl. That's because in
// canonicalization (see ASTContext.cpp), cdecl is canonicalized away
// because it is the default calling convention.
// Note also that we DO NOT return at this point, because we still have
// other tests to run.
const FunctionType *OldType = cast<FunctionType>(OldQType);
const FunctionType *NewType = New->getType()->getAs<FunctionType>();
FunctionType::ExtInfo OldTypeInfo = OldType->getExtInfo();
FunctionType::ExtInfo NewTypeInfo = NewType->getExtInfo();
bool RequiresAdjustment = false;
if (OldTypeInfo.getCC() != CC_Default &&
NewTypeInfo.getCC() == CC_Default) {
NewTypeInfo = NewTypeInfo.withCallingConv(OldTypeInfo.getCC());
RequiresAdjustment = true;
} else if (!Context.isSameCallConv(OldTypeInfo.getCC(),
NewTypeInfo.getCC())) {
// Calling conventions really aren't compatible, so complain.
Diag(New->getLocation(), diag::err_cconv_change)
<< FunctionType::getNameForCallConv(NewTypeInfo.getCC())
<< (OldTypeInfo.getCC() == CC_Default)
<< (OldTypeInfo.getCC() == CC_Default ? "" :
Diag(Old->getLocation(), diag::note_previous_declaration);
return true;
// FIXME: diagnose the other way around?
if (OldTypeInfo.getNoReturn() && !NewTypeInfo.getNoReturn()) {
NewTypeInfo = NewTypeInfo.withNoReturn(true);
RequiresAdjustment = true;
// Merge regparm attribute.
if (OldTypeInfo.getHasRegParm() != NewTypeInfo.getHasRegParm() ||
OldTypeInfo.getRegParm() != NewTypeInfo.getRegParm()) {
if (NewTypeInfo.getHasRegParm()) {
Diag(New->getLocation(), diag::err_regparm_mismatch)
<< NewType->getRegParmType()
<< OldType->getRegParmType();
Diag(Old->getLocation(), diag::note_previous_declaration);
return true;
NewTypeInfo = NewTypeInfo.withRegParm(OldTypeInfo.getRegParm());
RequiresAdjustment = true;
// Merge ns_returns_retained attribute.
if (OldTypeInfo.getProducesResult() != NewTypeInfo.getProducesResult()) {
if (NewTypeInfo.getProducesResult()) {
Diag(New->getLocation(), diag::err_returns_retained_mismatch);
Diag(Old->getLocation(), diag::note_previous_declaration);
return true;
NewTypeInfo = NewTypeInfo.withProducesResult(true);
RequiresAdjustment = true;
if (RequiresAdjustment) {
NewType = Context.adjustFunctionType(NewType, NewTypeInfo);
New->setType(QualType(NewType, 0));
NewQType = Context.getCanonicalType(New->getType());
if (getLangOpts().CPlusPlus) {
// (C++98 13.1p2):
// Certain function declarations cannot be overloaded:
// -- Function declarations that differ only in the return type
// cannot be overloaded.
QualType OldReturnType = OldType->getResultType();
QualType NewReturnType = cast<FunctionType>(NewQType)->getResultType();
QualType ResQT;
if (OldReturnType != NewReturnType) {
if (NewReturnType->isObjCObjectPointerType()
&& OldReturnType->isObjCObjectPointerType())
ResQT = Context.mergeObjCGCQualifiers(NewQType, OldQType);
if (ResQT.isNull()) {
if (New->isCXXClassMember() && New->isOutOfLine())
diag::err_member_def_does_not_match_ret_type) << New;
Diag(New->getLocation(), diag::err_ovl_diff_return_type);
Diag(Old->getLocation(), PrevDiag) << Old << Old->getType();
return true;
NewQType = ResQT;
const CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old);
CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New);
if (OldMethod && NewMethod) {
// Preserve triviality.
// MSVC allows explicit template specialization at class scope:
// 2 CXMethodDecls referring to the same function will be injected.
// We don't want a redeclartion error.
bool IsClassScopeExplicitSpecialization =
OldMethod->isFunctionTemplateSpecialization() &&
bool isFriend = NewMethod->getFriendObjectKind();
if (!isFriend && NewMethod->getLexicalDeclContext()->isRecord() &&
!IsClassScopeExplicitSpecialization) {
// -- Member function declarations with the same name and the
// same parameter types cannot be overloaded if any of them
// is a static member function declaration.
if (OldMethod->isStatic() || NewMethod->isStatic()) {
Diag(New->getLocation(), diag::err_ovl_static_nonstatic_member);
Diag(Old->getLocation(), PrevDiag) << Old << Old->getType();
return true;
// C++ [class.mem]p1:
// [...] A member shall not be declared twice in the
// member-specification, except that a nested class or member
// class template can be declared and then later defined.
if (ActiveTemplateInstantiations.empty()) {
unsigned NewDiag;
if (isa<CXXConstructorDecl>(OldMethod))
NewDiag = diag::err_constructor_redeclared;
else if (isa<CXXDestructorDecl>(NewMethod))
NewDiag = diag::err_destructor_redeclared;
else if (isa<CXXConversionDecl>(NewMethod))
NewDiag = diag::err_conv_function_redeclared;
NewDiag = diag::err_member_redeclared;
Diag(New->getLocation(), NewDiag);
} else {
Diag(New->getLocation(), diag::err_member_redeclared_in_instantiation)
<< New << New->getType();
Diag(Old->getLocation(), PrevDiag) << Old << Old->getType();
// Complain if this is an explicit declaration of a special
// member that was initially declared implicitly.
// As an exception, it's okay to befriend such methods in order
// to permit the implicit constructor/destructor/operator calls.
} else if (OldMethod->isImplicit()) {
if (isFriend) {
} else {
<< New << getSpecialMember(OldMethod);
return true;
} else if (OldMethod->isExplicitlyDefaulted() && !isFriend) {
<< getSpecialMember(OldMethod);
return true;
// (C++98 8.3.5p3):
// All declarations for a function shall agree exactly in both the
// return type and the parameter-type-list.
// We also want to respect all the extended bits except noreturn.
// noreturn should now match unless the old type info didn't have it.
QualType OldQTypeForComparison = OldQType;
if (!OldTypeInfo.getNoReturn() && NewTypeInfo.getNoReturn()) {
assert(OldQType == QualType(OldType, 0));
const FunctionType *OldTypeForComparison
= Context.adjustFunctionType(OldType, OldTypeInfo.withNoReturn(true));
OldQTypeForComparison = QualType(OldTypeForComparison, 0);
if (OldQTypeForComparison == NewQType)
return MergeCompatibleFunctionDecls(New, Old, S);
// Fall through for conflicting redeclarations and redefinitions.
// C: Function types need to be compatible, not identical. This handles
// duplicate function decls like "void f(int); void f(enum X);" properly.
if (!getLangOpts().CPlusPlus &&
Context.typesAreCompatible(OldQType, NewQType)) {
const FunctionType *OldFuncType = OldQType->getAs<FunctionType>();
const FunctionType *NewFuncType = NewQType->getAs<FunctionType>();
const FunctionProtoType *OldProto = 0;
if (isa<FunctionNoProtoType>(NewFuncType) &&
(OldProto = dyn_cast<FunctionProtoType>(OldFuncType))) {
// The old declaration provided a function prototype, but the
// new declaration does not. Merge in the prototype.
assert(!OldProto->hasExceptionSpec() && "Exception spec in C");
SmallVector<QualType, 16> ParamTypes(OldProto->arg_type_begin(),
NewQType = Context.getFunctionType(NewFuncType->getResultType(),, ParamTypes.size(),
// Synthesize a parameter for each argument type.
SmallVector<ParmVarDecl*, 16> Params;
for (FunctionProtoType::arg_type_iterator
ParamType = OldProto->arg_type_begin(),
ParamEnd = OldProto->arg_type_end();
ParamType != ParamEnd; ++ParamType) {
ParmVarDecl *Param = ParmVarDecl::Create(Context, New,
SourceLocation(), 0,
*ParamType, /*TInfo=*/0,
SC_None, SC_None,
Param->setScopeInfo(0, Params.size());
return MergeCompatibleFunctionDecls(New, Old, S);
// GNU C permits a K&R definition to follow a prototype declaration
// if the declared types of the parameters in the K&R definition
// match the types in the prototype declaration, even when the
// promoted types of the parameters from the K&R definition differ
// from the types in the prototype. GCC then keeps the types from
// the prototype.
// If a variadic prototype is followed by a non-variadic K&R definition,
// the K&R definition becomes variadic. This is sort of an edge case, but
// it's legal per the standard depending on how you read C99 and
// C99 6.9.1p8.
if (!getLangOpts().CPlusPlus &&
Old->hasPrototype() && !New->hasPrototype() &&
New->getType()->getAs<FunctionProtoType>() &&
Old->getNumParams() == New->getNumParams()) {
SmallVector<QualType, 16> ArgTypes;
SmallVector<GNUCompatibleParamWarning, 16> Warnings;
const FunctionProtoType *OldProto
= Old->getType()->getAs<FunctionProtoType>();
const FunctionProtoType *NewProto
= New->getType()->getAs<FunctionProtoType>();
// Determine whether this is the GNU C extension.
QualType MergedReturn = Context.mergeTypes(OldProto->getResultType(),
bool LooseCompatible = !MergedReturn.isNull();
for (unsigned Idx = 0, End = Old->getNumParams();
LooseCompatible && Idx != End; ++Idx) {
ParmVarDecl *OldParm = Old->getParamDecl(Idx);
ParmVarDecl *NewParm = New->getParamDecl(Idx);
if (Context.typesAreCompatible(OldParm->getType(),
NewProto->getArgType(Idx))) {
} else if (Context.typesAreCompatible(OldParm->getType(),
/*CompareUnqualified=*/true)) {
GNUCompatibleParamWarning Warn
= { OldParm, NewParm, NewProto->getArgType(Idx) };
} else
LooseCompatible = false;
if (LooseCompatible) {
for (unsigned Warn = 0; Warn < Warnings.size(); ++Warn) {
<< Warnings[Warn].PromotedType
<< Warnings[Warn].OldParm->getType();
if (Warnings[Warn].OldParm->getLocation().isValid())
New->setType(Context.getFunctionType(MergedReturn, &ArgTypes[0],
return MergeCompatibleFunctionDecls(New, Old, S);
// Fall through to diagnose conflicting types.
// A function that has already been declared has been redeclared or defined
// with a different type- show appropriate diagnostic
if (unsigned BuiltinID = Old->getBuiltinID()) {
// The user has declared a builtin function with an incompatible
// signature.
if (Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) {
// The function the user is redeclaring is a library-defined
// function like 'malloc' or 'printf'. Warn about the
// redeclaration, then pretend that we don't know about this
// library built-in.
Diag(New->getLocation(), diag::warn_redecl_library_builtin) << New;
Diag(Old->getLocation(), diag::note_previous_builtin_declaration)
<< Old << Old->getType();
return false;
PrevDiag = diag::note_previous_builtin_declaration;
Diag(New->getLocation(), diag::err_conflicting_types) << New->getDeclName();
Diag(Old->getLocation(), PrevDiag) << Old << Old->getType();
return true;
/// \brief Completes the merge of two function declarations that are
/// known to be compatible.
/// This routine handles the merging of attributes and other
/// properties of function declarations form the old declaration to
/// the new declaration, once we know that New is in fact a
/// redeclaration of Old.
/// \returns false
bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old,
Scope *S) {
// Merge the attributes
mergeDeclAttributes(New, Old);
// Merge the storage class.
if (Old->getStorageClass() != SC_Extern &&
Old->getStorageClass() != SC_None)
// Merge "pure" flag.
if (Old->isPure())
// Merge attributes from the parameters. These can mismatch with K&R
// declarations.
if (New->getNumParams() == Old->getNumParams())
for (unsigned i = 0, e = New->getNumParams(); i != e; ++i)
mergeParamDeclAttributes(New->getParamDecl(i), Old->getParamDecl(i),
if (getLangOpts().CPlusPlus)
return MergeCXXFunctionDecl(New, Old, S);
return false;
void Sema::mergeObjCMethodDecls(ObjCMethodDecl *newMethod,
ObjCMethodDecl *oldMethod) {
// Merge the attributes, including deprecated/unavailable
mergeDeclAttributes(newMethod, oldMethod, /* mergeDeprecation */true);
// Merge attributes from the parameters.
ObjCMethodDecl::param_const_iterator oi = oldMethod->param_begin(),
oe = oldMethod->param_end();
for (ObjCMethodDecl::param_iterator
ni = newMethod->param_begin(), ne = newMethod->param_end();
ni != ne && oi != oe; ++ni, ++oi)
mergeParamDeclAttributes(*ni, *oi, Context);
CheckObjCMethodOverride(newMethod, oldMethod, true);
/// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
/// scope as a previous declaration 'Old'. Figure out how to merge their types,
/// emitting diagnostics as appropriate.
/// Declarations using the auto type specifier (C++ []) call back
/// to here in AddInitializerToDecl. We can't check them before the initializer
/// is attached.
void Sema::MergeVarDeclTypes(VarDecl *New, VarDecl *Old) {
if (New->isInvalidDecl() || Old->isInvalidDecl())
QualType MergedT;
if (getLangOpts().CPlusPlus) {
AutoType *AT = New->getType()->getContainedAutoType();
if (AT && !AT->isDeduced()) {
// We don't know what the new type is until the initializer is attached.
} else if (Context.hasSameType(New->getType(), Old->getType())) {
// These could still be something that needs exception specs checked.
return MergeVarDeclExceptionSpecs(New, Old);
// C++ []p10:
// [...] the types specified by all declarations referring to a given
// object or function shall be identical, except that declarations for an
// array object can specify array types that differ by the presence or
// absence of a major array bound (8.3.4).
else if (Old->getType()->isIncompleteArrayType() &&
New->getType()->isArrayType()) {
CanQual<ArrayType> OldArray
= Context.getCanonicalType(Old->getType())->getAs<ArrayType>();
CanQual<ArrayType> NewArray
= Context.getCanonicalType(New->getType())->getAs<ArrayType>();
if (OldArray->getElementType() == NewArray->getElementType())
MergedT = New->getType();
} else if (Old->getType()->isArrayType() &&
New->getType()->isIncompleteArrayType()) {
CanQual<ArrayType> OldArray
= Context.getCanonicalType(Old->getType())->getAs<ArrayType>();
CanQual<ArrayType> NewArray
= Context.getCanonicalType(New->getType())->getAs<ArrayType>();
if (OldArray->getElementType() == NewArray->getElementType())
MergedT = Old->getType();
} else if (New->getType()->isObjCObjectPointerType()
&& Old->getType()->isObjCObjectPointerType()) {
MergedT = Context.mergeObjCGCQualifiers(New->getType(),
} else {
MergedT = Context.mergeTypes(New->getType(), Old->getType());
if (MergedT.isNull()) {
Diag(New->getLocation(), diag::err_redefinition_different_type)
<< New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
return New->setInvalidDecl();
/// MergeVarDecl - We just parsed a variable 'New' which has the same name
/// and scope as a previous declaration 'Old'. Figure out how to resolve this
/// situation, merging decls or emitting diagnostics as appropriate.
/// Tentative definition rules (C99 6.9.2p2) are checked by
/// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
/// definitions here, since the initializer hasn't been attached.
void Sema::MergeVarDecl(VarDecl *New, LookupResult &Previous) {
// If the new decl is already invalid, don't do any other checking.
if (New->isInvalidDecl())
// Verify the old decl was also a variable.
VarDecl *Old = 0;
if (!Previous.isSingleResult() ||
!(Old = dyn_cast<VarDecl>(Previous.getFoundDecl()))) {
Diag(New->getLocation(), diag::err_redefinition_different_kind)
<< New->getDeclName();
return New->setInvalidDecl();
// C++ [class.mem]p1:
// A member shall not be declared twice in the member-specification [...]
// Here, we need only consider static data members.
if (Old->isStaticDataMember() && !New->isOutOfLine()) {
Diag(New->getLocation(), diag::err_duplicate_member)
<< New->getIdentifier();
Diag(Old->getLocation(), diag::note_previous_declaration);
mergeDeclAttributes(New, Old);
// Warn if an already-declared variable is made a weak_import in a subsequent
// declaration
if (New->getAttr<WeakImportAttr>() &&
Old->getStorageClass() == SC_None &&
!Old->getAttr<WeakImportAttr>()) {
Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
// Remove weak_import attribute on new declaration.
// Merge the types.
MergeVarDeclTypes(New, Old);
if (New->isInvalidDecl())
// C99 6.2.2p4: Check if we have a static decl followed by a non-static.
if (New->getStorageClass() == SC_Static &&
(Old->getStorageClass() == SC_None || Old->hasExternalStorage())) {
Diag(New->getLocation(), diag::err_static_non_static) << New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
return New->setInvalidDecl();
// C99 6.2.2p4:
// For an identifier declared with the storage-class specifier
// extern in a scope in which a prior declaration of that
// identifier is visible,23) if the prior declaration specifies
// internal or external linkage, the linkage of the identifier at
// the later declaration is the same as the linkage specified at
// the prior declaration. If no prior declaration is visible, or
// if the prior declaration specifies no linkage, then the
// identifier has external linkage.
if (New->hasExternalStorage() && Old->hasLinkage())
/* Okay */;
else if (New->getStorageClass() != SC_Static &&
Old->getStorageClass() == SC_Static) {
Diag(New->getLocation(), diag::err_non_static_static) << New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_definition);
return New->setInvalidDecl();
// Check if extern is followed by non-extern and vice-versa.
if (