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-rw-r--r--lib/CodeGen/CGCXX.cpp113
-rw-r--r--lib/CodeGen/CodeGenModule.cpp29
-rw-r--r--lib/CodeGen/CodeGenModule.h26
3 files changed, 142 insertions, 26 deletions
diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index c4c52aac03..f0d01969a9 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -26,17 +26,88 @@
using namespace clang;
using namespace CodeGen;
+/// Try to emit a definition as a global alias for another definition.
+bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
+ GlobalDecl TargetDecl) {
+ // Find the referrent.
+ llvm::GlobalValue *Ref = cast<llvm::GlobalValue>(GetAddrOfGlobal(TargetDecl));
+
+ // Look for an existing entry.
+ const char *MangledName = getMangledName(AliasDecl);
+ llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
+ if (Entry) {
+ assert(Entry->isDeclaration() && "definition already exists for alias");
+ assert(Entry->getType() == Ref->getType() &&
+ "declaration exists with different type");
+ }
+
+ // The alias will use the linkage of the referrent. If we can't
+ // support aliases with that linkage, fail.
+ llvm::GlobalValue::LinkageTypes Linkage
+ = getFunctionLinkage(cast<FunctionDecl>(AliasDecl.getDecl()));
+
+ switch (Linkage) {
+ // We can definitely emit aliases to definitions with external linkage.
+ case llvm::GlobalValue::ExternalLinkage:
+ case llvm::GlobalValue::ExternalWeakLinkage:
+ break;
+
+ // Same with local linkage.
+ case llvm::GlobalValue::InternalLinkage:
+ case llvm::GlobalValue::PrivateLinkage:
+ case llvm::GlobalValue::LinkerPrivateLinkage:
+ break;
+
+ // We should try to support linkonce linkages.
+ case llvm::GlobalValue::LinkOnceAnyLinkage:
+ case llvm::GlobalValue::LinkOnceODRLinkage:
+ return true;
+
+ // Other linkages will probably never be supported.
+ default:
+ return true;
+ }
+
+ // Create the alias with no name.
+ llvm::GlobalAlias *Alias =
+ new llvm::GlobalAlias(Ref->getType(), Linkage, "", Ref, &getModule());
+
+ // Switch any previous uses to the alias and continue.
+ if (Entry) {
+ Entry->replaceAllUsesWith(Alias);
+ Entry->eraseFromParent();
+ }
+ Entry = Alias;
+
+ // Finally, set up the alias with its proper name and attributes.
+ Alias->setName(MangledName);
+ SetCommonAttributes(AliasDecl.getDecl(), Alias);
+
+ return false;
+}
void CodeGenModule::EmitCXXConstructors(const CXXConstructorDecl *D) {
- EmitGlobal(GlobalDecl(D, Ctor_Complete));
+ // The constructor used for constructing this as a base class;
+ // ignores virtual bases.
EmitGlobal(GlobalDecl(D, Ctor_Base));
+
+ // The constructor used for constructing this as a complete class;
+ // constucts the virtual bases, then calls the base constructor.
+ EmitGlobal(GlobalDecl(D, Ctor_Complete));
}
void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
CXXCtorType Type) {
+ // The complete constructor is equivalent to the base constructor
+ // for classes with no virtual bases. Try to emit it as an alias.
+ if (Type == Ctor_Complete &&
+ !D->getParent()->getNumVBases() &&
+ !TryEmitDefinitionAsAlias(GlobalDecl(D, Ctor_Complete),
+ GlobalDecl(D, Ctor_Base)))
+ return;
- llvm::Function *Fn = GetAddrOfCXXConstructor(D, Type);
+ llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXConstructor(D, Type));
CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
@@ -44,15 +115,17 @@ void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
SetLLVMFunctionAttributesForDefinition(D, Fn);
}
-llvm::Function *
+llvm::GlobalValue *
CodeGenModule::GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
CXXCtorType Type) {
+ const char *Name = getMangledCXXCtorName(D, Type);
+ if (llvm::GlobalValue *V = GlobalDeclMap[Name])
+ return V;
+
const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
const llvm::FunctionType *FTy =
getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type),
FPT->isVariadic());
-
- const char *Name = getMangledCXXCtorName(D, Type);
return cast<llvm::Function>(
GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
}
@@ -67,15 +140,32 @@ const char *CodeGenModule::getMangledCXXCtorName(const CXXConstructorDecl *D,
}
void CodeGenModule::EmitCXXDestructors(const CXXDestructorDecl *D) {
+ // The destructor used for destructing this as a base class; ignores
+ // virtual bases.
+ EmitGlobal(GlobalDecl(D, Dtor_Base));
+
+ // The destructor used for destructing this as a most-derived class;
+ // call the base destructor and then destructs any virtual bases.
+ EmitGlobal(GlobalDecl(D, Dtor_Complete));
+
+ // The destructor in a virtual table is always a 'deleting'
+ // destructor, which calls the complete destructor and then uses the
+ // appropriate operator delete.
if (D->isVirtual())
EmitGlobal(GlobalDecl(D, Dtor_Deleting));
- EmitGlobal(GlobalDecl(D, Dtor_Complete));
- EmitGlobal(GlobalDecl(D, Dtor_Base));
}
void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
CXXDtorType Type) {
- llvm::Function *Fn = GetAddrOfCXXDestructor(D, Type);
+ // The complete destructor is equivalent to the base destructor for
+ // classes with no virtual bases, so try to emit it as an alias.
+ if (Type == Dtor_Complete &&
+ !D->getParent()->getNumVBases() &&
+ !TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Complete),
+ GlobalDecl(D, Dtor_Base)))
+ return;
+
+ llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXDestructor(D, Type));
CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
@@ -83,13 +173,16 @@ void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
SetLLVMFunctionAttributesForDefinition(D, Fn);
}
-llvm::Function *
+llvm::GlobalValue *
CodeGenModule::GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
CXXDtorType Type) {
+ const char *Name = getMangledCXXDtorName(D, Type);
+ if (llvm::GlobalValue *V = GlobalDeclMap[Name])
+ return V;
+
const llvm::FunctionType *FTy =
getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), false);
- const char *Name = getMangledCXXDtorName(D, Type);
return cast<llvm::Function>(
GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
}
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 5a552c490a..41575e41e5 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -316,24 +316,20 @@ GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
return CodeGenModule::GVA_CXXInline;
}
-/// SetFunctionDefinitionAttributes - Set attributes for a global.
-///
-/// FIXME: This is currently only done for aliases and functions, but not for
-/// variables (these details are set in EmitGlobalVarDefinition for variables).
-void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
- llvm::GlobalValue *GV) {
+llvm::GlobalValue::LinkageTypes
+CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
if (Linkage == GVA_Internal) {
- GV->setLinkage(llvm::Function::InternalLinkage);
+ return llvm::Function::InternalLinkage;
} else if (D->hasAttr<DLLExportAttr>()) {
- GV->setLinkage(llvm::Function::DLLExportLinkage);
+ return llvm::Function::DLLExportLinkage;
} else if (D->hasAttr<WeakAttr>()) {
- GV->setLinkage(llvm::Function::WeakAnyLinkage);
+ return llvm::Function::WeakAnyLinkage;
} else if (Linkage == GVA_C99Inline) {
// In C99 mode, 'inline' functions are guaranteed to have a strong
// definition somewhere else, so we can use available_externally linkage.
- GV->setLinkage(llvm::Function::AvailableExternallyLinkage);
+ return llvm::Function::AvailableExternallyLinkage;
} else if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) {
// In C++, the compiler has to emit a definition in every translation unit
// that references the function. We should use linkonce_odr because
@@ -341,13 +337,22 @@ void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
// don't need to codegen it. b) if the function persists, it needs to be
// merged with other definitions. c) C++ has the ODR, so we know the
// definition is dependable.
- GV->setLinkage(llvm::Function::LinkOnceODRLinkage);
+ return llvm::Function::LinkOnceODRLinkage;
} else {
assert(Linkage == GVA_StrongExternal);
// Otherwise, we have strong external linkage.
- GV->setLinkage(llvm::Function::ExternalLinkage);
+ return llvm::Function::ExternalLinkage;
}
+}
+
+/// SetFunctionDefinitionAttributes - Set attributes for a global.
+///
+/// FIXME: This is currently only done for aliases and functions, but not for
+/// variables (these details are set in EmitGlobalVarDefinition for variables).
+void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
+ llvm::GlobalValue *GV) {
+ GV->setLinkage(getFunctionLinkage(D));
SetCommonAttributes(D, GV);
}
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 8280766c70..a5e1d9f12b 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -206,6 +206,19 @@ public:
/// GlobalValue.
void setGlobalVisibility(llvm::GlobalValue *GV, const Decl *D) const;
+ llvm::Constant *GetAddrOfGlobal(GlobalDecl GD) {
+ if (isa<CXXConstructorDecl>(GD.getDecl()))
+ return GetAddrOfCXXConstructor(cast<CXXConstructorDecl>(GD.getDecl()),
+ GD.getCtorType());
+ else if (isa<CXXDestructorDecl>(GD.getDecl()))
+ return GetAddrOfCXXDestructor(cast<CXXDestructorDecl>(GD.getDecl()),
+ GD.getDtorType());
+ else if (isa<FunctionDecl>(GD.getDecl()))
+ return GetAddrOfFunction(GD);
+ else
+ return GetAddrOfGlobalVar(cast<VarDecl>(GD.getDecl()));
+ }
+
/// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
/// given global variable. If Ty is non-null and if the global doesn't exist,
/// then it will be greated with the specified type instead of whatever the
@@ -291,13 +304,13 @@ public:
/// GetAddrOfCXXConstructor - Return the address of the constructor of the
/// given type.
- llvm::Function *GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
- CXXCtorType Type);
+ llvm::GlobalValue *GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
+ CXXCtorType Type);
/// GetAddrOfCXXDestructor - Return the address of the constructor of the
/// given type.
- llvm::Function *GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
- CXXDtorType Type);
+ llvm::GlobalValue *GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
+ CXXDtorType Type);
/// getBuiltinLibFunction - Given a builtin id for a function like
/// "__builtin_fabsf", return a Function* for "fabsf".
@@ -417,6 +430,9 @@ public:
GVA_TemplateInstantiation
};
+ llvm::GlobalVariable::LinkageTypes
+ getFunctionLinkage(const FunctionDecl *FD);
+
/// getVtableLinkage - Return the appropriate linkage for the vtable, VTT,
/// and type information of the given class.
static llvm::GlobalVariable::LinkageTypes
@@ -468,6 +484,8 @@ private:
// C++ related functions.
+ bool TryEmitDefinitionAsAlias(GlobalDecl Alias, GlobalDecl Target);
+
void EmitNamespace(const NamespaceDecl *D);
void EmitLinkageSpec(const LinkageSpecDecl *D);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-05-09 11:08:49 +0000