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Merge PCHWriterDecl.cpp's isRequiredDecl and CodeGenModule::MayDeferGeneration into a new function, 

DeclIsRequiredFunctionOrFileScopedVar.

This is essentially a CodeGen predicate that is also needed by the PCH mechanism to determine whether a decl
needs to be deserialized during PCH loading for codegen purposes.
Since this logic is shared by CodeGen and the PCH mechanism, move it to the ASTContext,
thus CodeGenModule's GetLinkageForFunction/GetLinkageForVariable and the GVALinkage enum is moved out of CodeGen.

This fixes current (and avoids future) codegen-from-PCH bugs.

llvm-svn: 109784
This commit is contained in:
Argyrios Kyrtzidis 2010-07-29 18:15:58 +00:00
parent 7f4b81af7a
commit c81af03fb3
8 changed files with 192 additions and 215 deletions
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11
clang/include/clang/AST/ASTContext.h
View File

@ -1339,6 +1339,17 @@ public:
/// when it is called.
void AddDeallocation(void (*Callback)(void*), void *Data);
GVALinkage GetGVALinkageForFunction(const FunctionDecl *FD);
GVALinkage GetGVALinkageForVariable(const VarDecl *VD);
/// \brief Determines if the decl can be CodeGen'ed or deserialized from PCH
/// lazily, only when used; this is only relevant for function or file scoped
/// var definitions.
///
/// \returns true if the function/var must be CodeGen'ed/deserialized even if
/// it is not used.
bool DeclIsRequiredFunctionOrFileScopedVar(const Decl *D);
//===--------------------------------------------------------------------===//
// Statistics
//===--------------------------------------------------------------------===//

11
clang/include/clang/Basic/Linkage.h
View File

@ -41,6 +41,17 @@ enum Linkage {
ExternalLinkage
};
/// \brief A more specific kind of linkage. This is relevant to CodeGen and
/// PCH reading.
enum GVALinkage {
GVA_Internal,
GVA_C99Inline,
GVA_CXXInline,
GVA_StrongExternal,
GVA_TemplateInstantiation,
GVA_ExplicitTemplateInstantiation
};
/// \brief Determine whether the given linkage is semantically
/// external.
inline bool isExternalLinkage(Linkage L) {

160
clang/lib/AST/ASTContext.cpp
View File

@ -5445,3 +5445,163 @@ ASTContext::UsualArithmeticConversionsType(QualType lhs, QualType rhs) {
}
return destType;
}
GVALinkage ASTContext::GetGVALinkageForFunction(const FunctionDecl *FD) {
GVALinkage External = GVA_StrongExternal;
Linkage L = FD->getLinkage();
if (L == ExternalLinkage && getLangOptions().CPlusPlus &&
FD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return GVA_Internal;
case ExternalLinkage:
switch (FD->getTemplateSpecializationKind()) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
External = GVA_StrongExternal;
break;
case TSK_ExplicitInstantiationDefinition:
return GVA_ExplicitTemplateInstantiation;
case TSK_ExplicitInstantiationDeclaration:
case TSK_ImplicitInstantiation:
External = GVA_TemplateInstantiation;
break;
}
}
if (!FD->isInlined())
return External;
if (!getLangOptions().CPlusPlus || FD->hasAttr<GNUInlineAttr>()) {
// GNU or C99 inline semantics. Determine whether this symbol should be
// externally visible.
if (FD->isInlineDefinitionExternallyVisible())
return External;
// C99 inline semantics, where the symbol is not externally visible.
return GVA_C99Inline;
}
// C++0x [temp.explicit]p9:
// [ Note: The intent is that an inline function that is the subject of
// an explicit instantiation declaration will still be implicitly
// instantiated when used so that the body can be considered for
// inlining, but that no out-of-line copy of the inline function would be
// generated in the translation unit. -- end note ]
if (FD->getTemplateSpecializationKind()
== TSK_ExplicitInstantiationDeclaration)
return GVA_C99Inline;
return GVA_CXXInline;
}
GVALinkage ASTContext::GetGVALinkageForVariable(const VarDecl *VD) {
// If this is a static data member, compute the kind of template
// specialization. Otherwise, this variable is not part of a
// template.
TemplateSpecializationKind TSK = TSK_Undeclared;
if (VD->isStaticDataMember())
TSK = VD->getTemplateSpecializationKind();
Linkage L = VD->getLinkage();
if (L == ExternalLinkage && getLangOptions().CPlusPlus &&
VD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return GVA_Internal;
case ExternalLinkage:
switch (TSK) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
return GVA_StrongExternal;
case TSK_ExplicitInstantiationDeclaration:
llvm_unreachable("Variable should not be instantiated");
// Fall through to treat this like any other instantiation.
case TSK_ExplicitInstantiationDefinition:
return GVA_ExplicitTemplateInstantiation;
case TSK_ImplicitInstantiation:
return GVA_TemplateInstantiation;
}
}
return GVA_StrongExternal;
}
bool ASTContext::DeclIsRequiredFunctionOrFileScopedVar(const Decl *D) {
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (!VD->isFileVarDecl())
return false;
} else if (!isa<FunctionDecl>(D))
return false;
// Aliases and used decls are required.
if (D->hasAttr<AliasAttr>() || D->hasAttr<UsedAttr>())
return true;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// Forward declarations aren't required.
if (!FD->isThisDeclarationADefinition())
return false;
// Constructors and destructors are required.
if (FD->hasAttr<ConstructorAttr>() || FD->hasAttr<DestructorAttr>())
return true;
// The key function for a class is required.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
const CXXRecordDecl *RD = MD->getParent();
if (MD->isOutOfLine() && RD->isDynamicClass()) {
const CXXMethodDecl *KeyFunc = getKeyFunction(RD);
if (KeyFunc && KeyFunc->getCanonicalDecl() == MD->getCanonicalDecl())
return true;
}
}
GVALinkage Linkage = GetGVALinkageForFunction(FD);
// static, static inline, always_inline, and extern inline functions can
// always be deferred. Normal inline functions can be deferred in C99/C++.
// Implicit template instantiations can also be deferred in C++.
if (Linkage == GVA_Internal || Linkage == GVA_C99Inline ||
Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation)
return false;
return true;
}
const VarDecl *VD = cast<VarDecl>(D);
assert(VD->isFileVarDecl() && "Expected file scoped var");
// Structs that have non-trivial constructors or destructors are required.
// FIXME: Handle references.
if (const RecordType *RT = VD->getType()->getAs<RecordType>()) {
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
if (!RD->hasTrivialConstructor() || !RD->hasTrivialDestructor())
return true;
}
}
GVALinkage L = GetGVALinkageForVariable(VD);
if (L == GVA_Internal || L == GVA_TemplateInstantiation) {
if (!(VD->getInit() && VD->getInit()->HasSideEffects(*this)))
return false;
}
return true;
}

159
clang/lib/CodeGen/CodeGenModule.cpp
View File

@ -322,68 +322,9 @@ void CodeGenModule::EmitAnnotations() {
gv->setSection("llvm.metadata");
}
static CodeGenModule::GVALinkage
GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
const LangOptions &Features) {
CodeGenModule::GVALinkage External = CodeGenModule::GVA_StrongExternal;
Linkage L = FD->getLinkage();
if (L == ExternalLinkage && Context.getLangOptions().CPlusPlus &&
FD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return CodeGenModule::GVA_Internal;
case ExternalLinkage:
switch (FD->getTemplateSpecializationKind()) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
External = CodeGenModule::GVA_StrongExternal;
break;
case TSK_ExplicitInstantiationDefinition:
return CodeGenModule::GVA_ExplicitTemplateInstantiation;
case TSK_ExplicitInstantiationDeclaration:
case TSK_ImplicitInstantiation:
External = CodeGenModule::GVA_TemplateInstantiation;
break;
}
}
if (!FD->isInlined())
return External;
if (!Features.CPlusPlus || FD->hasAttr<GNUInlineAttr>()) {
// GNU or C99 inline semantics. Determine whether this symbol should be
// externally visible.
if (FD->isInlineDefinitionExternallyVisible())
return External;
// C99 inline semantics, where the symbol is not externally visible.
return CodeGenModule::GVA_C99Inline;
}
// C++0x [temp.explicit]p9:
// [ Note: The intent is that an inline function that is the subject of
// an explicit instantiation declaration will still be implicitly
// instantiated when used so that the body can be considered for
// inlining, but that no out-of-line copy of the inline function would be
// generated in the translation unit. -- end note ]
if (FD->getTemplateSpecializationKind()
== TSK_ExplicitInstantiationDeclaration)
return CodeGenModule::GVA_C99Inline;
return CodeGenModule::GVA_CXXInline;
}
llvm::GlobalValue::LinkageTypes
CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
GVALinkage Linkage = getContext().GetGVALinkageForFunction(D);
if (Linkage == GVA_Internal)
return llvm::Function::InternalLinkage;
@ -641,102 +582,12 @@ llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
return llvm::ConstantStruct::get(VMContext, Fields, 4, false);
}
static CodeGenModule::GVALinkage
GetLinkageForVariable(ASTContext &Context, const VarDecl *VD) {
// If this is a static data member, compute the kind of template
// specialization. Otherwise, this variable is not part of a
// template.
TemplateSpecializationKind TSK = TSK_Undeclared;
if (VD->isStaticDataMember())
TSK = VD->getTemplateSpecializationKind();
Linkage L = VD->getLinkage();
if (L == ExternalLinkage && Context.getLangOptions().CPlusPlus &&
VD->getType()->getLinkage() == UniqueExternalLinkage)
L = UniqueExternalLinkage;
switch (L) {
case NoLinkage:
case InternalLinkage:
case UniqueExternalLinkage:
return CodeGenModule::GVA_Internal;
case ExternalLinkage:
switch (TSK) {
case TSK_Undeclared:
case TSK_ExplicitSpecialization:
return CodeGenModule::GVA_StrongExternal;
case TSK_ExplicitInstantiationDeclaration:
llvm_unreachable("Variable should not be instantiated");
// Fall through to treat this like any other instantiation.
case TSK_ExplicitInstantiationDefinition:
return CodeGenModule::GVA_ExplicitTemplateInstantiation;
case TSK_ImplicitInstantiation:
return CodeGenModule::GVA_TemplateInstantiation;
}
}
return CodeGenModule::GVA_StrongExternal;
}
bool CodeGenModule::MayDeferGeneration(const ValueDecl *Global) {
// Never defer when EmitAllDecls is specified or the decl has
// attribute used.
if (Features.EmitAllDecls || Global->hasAttr<UsedAttr>())
// Never defer when EmitAllDecls is specified.
if (Features.EmitAllDecls)
return false;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(Global)) {
// Constructors and destructors should never be deferred.
if (FD->hasAttr<ConstructorAttr>() ||
FD->hasAttr<DestructorAttr>())
return false;
// The key function for a class must never be deferred.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Global)) {
const CXXRecordDecl *RD = MD->getParent();
if (MD->isOutOfLine() && RD->isDynamicClass()) {
const CXXMethodDecl *KeyFunction = getContext().getKeyFunction(RD);
if (KeyFunction &&
KeyFunction->getCanonicalDecl() == MD->getCanonicalDecl())
return false;
}
}
GVALinkage Linkage = GetLinkageForFunction(getContext(), FD, Features);
// static, static inline, always_inline, and extern inline functions can
// always be deferred. Normal inline functions can be deferred in C99/C++.
// Implicit template instantiations can also be deferred in C++.
if (Linkage == GVA_Internal || Linkage == GVA_C99Inline ||
Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation)
return true;
return false;
}
const VarDecl *VD = cast<VarDecl>(Global);
assert(VD->isFileVarDecl() && "Invalid decl");
// We never want to defer structs that have non-trivial constructors or
// destructors.
// FIXME: Handle references.
if (const RecordType *RT = VD->getType()->getAs<RecordType>()) {
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
if (!RD->hasTrivialConstructor() || !RD->hasTrivialDestructor())
return false;
}
}
GVALinkage L = GetLinkageForVariable(getContext(), VD);
if (L == GVA_Internal || L == GVA_TemplateInstantiation) {
if (!(VD->getInit() && VD->getInit()->HasSideEffects(Context)))
return true;
}
return false;
return !getContext().DeclIsRequiredFunctionOrFileScopedVar(Global);
}
llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
@ -1271,7 +1122,7 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
GV->setAlignment(getContext().getDeclAlign(D).getQuantity());
// Set the llvm linkage type as appropriate.
GVALinkage Linkage = GetLinkageForVariable(getContext(), D);
GVALinkage Linkage = getContext().GetGVALinkageForVariable(D);
if (Linkage == GVA_Internal)
GV->setLinkage(llvm::Function::InternalLinkage);
else if (D->hasAttr<DLLImportAttr>())

9
clang/lib/CodeGen/CodeGenModule.h
View File

@ -504,15 +504,6 @@ public:
void EmitVTable(CXXRecordDecl *Class, bool DefinitionRequired);
enum GVALinkage {
GVA_Internal,
GVA_C99Inline,
GVA_CXXInline,
GVA_StrongExternal,
GVA_TemplateInstantiation,
GVA_ExplicitTemplateInstantiation
};
llvm::GlobalVariable::LinkageTypes
getFunctionLinkage(const FunctionDecl *FD);

53
clang/lib/Frontend/PCHWriterDecl.cpp
View File

@ -1081,63 +1081,12 @@ void PCHWriter::WriteDeclsBlockAbbrevs() {
/// clients to use a separate API call to "realize" the decl. This should be
/// relatively painless since they would presumably only do it for top-level
/// decls.
//
// FIXME: This predicate is essentially IRgen's predicate to determine whether a
// declaration can be deferred. Merge them somehow.
static bool isRequiredDecl(const Decl *D, ASTContext &Context) {
// File scoped assembly must be seen.
if (isa<FileScopeAsmDecl>(D))
return true;
// Otherwise if this isn't a function or a file scoped variable it doesn't
// need to be seen.
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (!VD->isFileVarDecl())
return false;
} else if (!isa<FunctionDecl>(D))
return false;
// Aliases and used decls must be seen.
if (D->hasAttr<AliasAttr>() || D->hasAttr<UsedAttr>())
return true;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// Forward declarations don't need to be seen.
if (!FD->isThisDeclarationADefinition())
return false;
// Constructors and destructors must be seen.
if (FD->hasAttr<ConstructorAttr>() || FD->hasAttr<DestructorAttr>())
return true;
// Otherwise, this is required unless it is static.
//
// FIXME: Inlines.
return FD->getStorageClass() != FunctionDecl::Static;
} else {
const VarDecl *VD = cast<VarDecl>(D);
// Structs that have non-trivial constructors or destructors must be seen.
if (const RecordType *RT = VD->getType()->getAs<RecordType>()) {
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
if (!RD->hasTrivialConstructor() || !RD->hasTrivialDestructor())
return true;
}
}
// In C++, this doesn't need to be seen if it is marked "extern".
if (Context.getLangOptions().CPlusPlus && !VD->getInit() &&
(VD->getStorageClass() == VarDecl::Extern ||
VD->isExternC()))
return false;
// In C, this doesn't need to be seen unless it is a definition.
if (!Context.getLangOptions().CPlusPlus && !VD->getInit())
return false;
// Otherwise, this is required unless it is static.
return VD->getStorageClass() != VarDecl::Static;
}
return Context.DeclIsRequiredFunctionOrFileScopedVar(D);
}
void PCHWriter::WriteDecl(ASTContext &Context, Decl *D) {

1
clang/test/PCH/cxx-required-decls.cpp
View File

@ -6,3 +6,4 @@
// RUN: %clang_cc1 -include-pch %t %s -emit-llvm -o - | FileCheck %s
// CHECK: @_ZL5globS = internal global %struct.S zeroinitializer
// CHECK: @_ZL3bar = internal global i32 0, align 4

3
clang/test/PCH/cxx-required-decls.h
View File

@ -5,3 +5,6 @@ struct S {
};
static S globS;
extern int ext_foo;
static int bar = ++ext_foo;