Use llvm.compiler.used instead of llvm.used for objc symbols.
LLVM currently has a hack (shouldEmitUsedDirectiveFor) that causes it to not
print no_dead_strip for symbols starting with 'l' or 'L'. These are exactly the
ones that the clang's objc codegen is producing. The net result, is that it is
equivalent to llvm.compiler.used.
The need for putting the private symbol in llvm.compiler.used should be clear
(the objc runtime uses them). The reason for also putting the weak symbols in
it is for LTO: ld64 will not ask us to preserve the it.
llvm-svn: 203172
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 8ce0303..46de0e5 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -332,7 +332,7 @@
var->setSection(SA->getName());
if (D.hasAttr<UsedAttr>())
- CGM.AddUsedGlobal(var);
+ CGM.addUsedGlobal(var);
// We may have to cast the constant because of the initializer
// mismatch above.
diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 0cb38f2..bd7c8bf 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -2676,7 +2676,7 @@
Protocols[PD->getIdentifier()] = Entry;
}
assertPrivateName(Entry);
- CGM.AddUsedGlobal(Entry);
+ CGM.addCompilerUsedGlobal(Entry);
return Entry;
}
@@ -3156,7 +3156,7 @@
GV->setInitializer(Init);
GV->setSection(Section);
GV->setAlignment(4);
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
} else
GV = CreateMetadataVar(Name, Init, Section, 4, true);
assertPrivateName(GV);
@@ -3229,7 +3229,7 @@
assertPrivateName(GV);
GV->setSection("__OBJC,__meta_class,regular,no_dead_strip");
GV->setAlignment(4);
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
return GV;
}
@@ -3446,7 +3446,7 @@
if (Align)
GV->setAlignment(Align);
if (AddToUsed)
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
return GV;
}
@@ -5006,7 +5006,7 @@
assertPrivateName(I->second);
I->second->setInitializer(llvm::ConstantStruct::get(ObjCTypes.ProtocolTy,
Values));
- CGM.AddUsedGlobal(I->second);
+ CGM.addCompilerUsedGlobal(I->second);
}
// Add assembler directives to add lazy undefined symbol references
@@ -5534,7 +5534,7 @@
assertPrivateName(GV);
GV->setAlignment(CGM.getDataLayout().getABITypeAlignment(Init->getType()));
GV->setSection(SectionName);
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
}
void CGObjCNonFragileABIMac::FinishNonFragileABIModule() {
@@ -5960,7 +5960,7 @@
ProtocolName);
PTGV->setSection("__DATA, __objc_protorefs, coalesced, no_dead_strip");
PTGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
- CGM.AddUsedGlobal(PTGV);
+ CGM.addCompilerUsedGlobal(PTGV);
return CGF.Builder.CreateLoad(PTGV);
}
@@ -6048,7 +6048,7 @@
GCATV->setAlignment(
CGM.getDataLayout().getABITypeAlignment(ObjCTypes.CategorynfABITy));
GCATV->setSection("__DATA, __objc_const");
- CGM.AddUsedGlobal(GCATV);
+ CGM.addCompilerUsedGlobal(GCATV);
DefinedCategories.push_back(GCATV);
// Determine if this category is also "non-lazy".
@@ -6108,7 +6108,7 @@
assertPrivateName(GV);
GV->setAlignment(CGM.getDataLayout().getABITypeAlignment(Init->getType()));
GV->setSection(Section);
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
return llvm::ConstantExpr::getBitCast(GV, ObjCTypes.MethodListnfABIPtrTy);
}
@@ -6229,7 +6229,7 @@
CGM.getDataLayout().getABITypeAlignment(Init->getType()));
GV->setSection("__DATA, __objc_const");
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
return llvm::ConstantExpr::getBitCast(GV, ObjCTypes.IvarListnfABIPtrTy);
}
@@ -6372,7 +6372,7 @@
Protocols[PD->getIdentifier()] = Entry;
}
Entry->setVisibility(llvm::GlobalValue::HiddenVisibility);
- CGM.AddUsedGlobal(Entry);
+ CGM.addCompilerUsedGlobal(Entry);
// Use this protocol meta-data to build protocol list table in section
// __DATA, __objc_protolist
@@ -6384,7 +6384,7 @@
CGM.getDataLayout().getABITypeAlignment(ObjCTypes.ProtocolnfABIPtrTy));
PTGV->setSection("__DATA, __objc_protolist, coalesced, no_dead_strip");
PTGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
- CGM.AddUsedGlobal(PTGV);
+ CGM.addCompilerUsedGlobal(PTGV);
return Entry;
}
@@ -6437,7 +6437,7 @@
GV->setSection("__DATA, __objc_const");
GV->setAlignment(
CGM.getDataLayout().getABITypeAlignment(Init->getType()));
- CGM.AddUsedGlobal(GV);
+ CGM.addCompilerUsedGlobal(GV);
return llvm::ConstantExpr::getBitCast(GV,
ObjCTypes.ProtocolListnfABIPtrTy);
}
@@ -6683,7 +6683,7 @@
CGM.getDataLayout().getABITypeAlignment(
ObjCTypes.ClassnfABIPtrTy));
Entry->setSection("__DATA, __objc_classrefs, regular, no_dead_strip");
- CGM.AddUsedGlobal(Entry);
+ CGM.addCompilerUsedGlobal(Entry);
}
assertPrivateName(Entry);
return CGF.Builder.CreateLoad(Entry);
@@ -6717,7 +6717,7 @@
CGM.getDataLayout().getABITypeAlignment(
ObjCTypes.ClassnfABIPtrTy));
Entry->setSection("__DATA, __objc_superrefs, regular, no_dead_strip");
- CGM.AddUsedGlobal(Entry);
+ CGM.addCompilerUsedGlobal(Entry);
}
assertPrivateName(Entry);
return CGF.Builder.CreateLoad(Entry);
@@ -6742,7 +6742,7 @@
CGM.getDataLayout().getABITypeAlignment(ObjCTypes.ClassnfABIPtrTy));
Entry->setSection("__DATA, __objc_superrefs, regular, no_dead_strip");
- CGM.AddUsedGlobal(Entry);
+ CGM.addCompilerUsedGlobal(Entry);
}
assertPrivateName(Entry);
@@ -6827,7 +6827,7 @@
Casted, "\01L_OBJC_SELECTOR_REFERENCES_");
Entry->setExternallyInitialized(true);
Entry->setSection("__DATA, __objc_selrefs, literal_pointers, no_dead_strip");
- CGM.AddUsedGlobal(Entry);
+ CGM.addCompilerUsedGlobal(Entry);
}
assertPrivateName(Entry);
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index f0265b3..9b3e329 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -258,7 +258,7 @@
EmitCtorList(GlobalDtors, "llvm.global_dtors");
EmitGlobalAnnotations();
EmitStaticExternCAliases();
- EmitLLVMUsed();
+ emitLLVMUsed();
if (CodeGenOpts.Autolink &&
(Context.getLangOpts().Modules || !LinkerOptionsMetadata.empty())) {
@@ -699,7 +699,7 @@
GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
if (D->hasAttr<UsedAttr>())
- AddUsedGlobal(GV);
+ addUsedGlobal(GV);
if (const SectionAttr *SA = D->getAttr<SectionAttr>())
GV->setSection(SA->getName());
@@ -776,39 +776,51 @@
llvm::Attribute::NoBuiltin);
}
-void CodeGenModule::AddUsedGlobal(llvm::GlobalValue *GV) {
+void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV) {
assert(!GV->isDeclaration() &&
"Only globals with definition can force usage.");
LLVMUsed.push_back(GV);
}
-void CodeGenModule::EmitLLVMUsed() {
+void CodeGenModule::addCompilerUsedGlobal(llvm::GlobalValue *GV) {
+ assert(!GV->isDeclaration() &&
+ "Only globals with definition can force usage.");
+ LLVMCompilerUsed.push_back(GV);
+}
+
+static void emitUsed(CodeGenModule &CGM, StringRef Name,
+ std::vector<llvm::WeakVH> &List) {
// Don't create llvm.used if there is no need.
- if (LLVMUsed.empty())
+ if (List.empty())
return;
- // Convert LLVMUsed to what ConstantArray needs.
+ // Convert List to what ConstantArray needs.
SmallVector<llvm::Constant*, 8> UsedArray;
- UsedArray.resize(LLVMUsed.size());
- for (unsigned i = 0, e = LLVMUsed.size(); i != e; ++i) {
+ UsedArray.resize(List.size());
+ for (unsigned i = 0, e = List.size(); i != e; ++i) {
UsedArray[i] =
- llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*LLVMUsed[i]),
- Int8PtrTy);
+ llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(&*List[i]),
+ CGM.Int8PtrTy);
}
if (UsedArray.empty())
return;
- llvm::ArrayType *ATy = llvm::ArrayType::get(Int8PtrTy, UsedArray.size());
+ llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
llvm::GlobalVariable *GV =
- new llvm::GlobalVariable(getModule(), ATy, false,
+ new llvm::GlobalVariable(CGM.getModule(), ATy, false,
llvm::GlobalValue::AppendingLinkage,
llvm::ConstantArray::get(ATy, UsedArray),
- "llvm.used");
+ Name);
GV->setSection("llvm.metadata");
}
+void CodeGenModule::emitLLVMUsed() {
+ emitUsed(*this, "llvm.used", LLVMUsed);
+ emitUsed(*this, "llvm.compiler.used", LLVMCompilerUsed);
+}
+
void CodeGenModule::AppendLinkerOptions(StringRef Opts) {
llvm::Value *MDOpts = llvm::MDString::get(getLLVMContext(), Opts);
LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
@@ -3054,7 +3066,7 @@
IdentifierInfo *Name = I->first;
llvm::GlobalValue *Val = I->second;
if (Val && !getModule().getNamedValue(Name->getName()))
- AddUsedGlobal(new llvm::GlobalAlias(Val->getType(), Val->getLinkage(),
+ addUsedGlobal(new llvm::GlobalAlias(Val->getType(), Val->getLinkage(),
Name->getName(), Val, &getModule()));
}
}
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 151cb33..11272fc 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -298,6 +298,7 @@
/// forcing visibility of symbols which may otherwise be optimized
/// out.
std::vector<llvm::WeakVH> LLVMUsed;
+ std::vector<llvm::WeakVH> LLVMCompilerUsed;
/// GlobalCtors - Store the list of global constructors and their respective
/// priorities to be emitted when the translation unit is complete.
@@ -799,10 +800,11 @@
template<typename SomeDecl>
void MaybeHandleStaticInExternC(const SomeDecl *D, llvm::GlobalValue *GV);
- /// AddUsedGlobal - Add a global which should be forced to be
- /// present in the object file; these are emitted to the llvm.used
- /// metadata global.
- void AddUsedGlobal(llvm::GlobalValue *GV);
+ /// Add a global to a list to be added to the llvm.used metadata.
+ void addUsedGlobal(llvm::GlobalValue *GV);
+
+ /// Add a global to a list to be added to the llvm.compiler.used metadata.
+ void addCompilerUsedGlobal(llvm::GlobalValue *GV);
/// AddCXXDtorEntry - Add a destructor and object to add to the C++ global
/// destructor function.
@@ -1104,9 +1106,8 @@
/// still have a use for.
void EmitDeferredVTables();
- /// EmitLLVMUsed - Emit the llvm.used metadata used to force
- /// references to global which may otherwise be optimized out.
- void EmitLLVMUsed();
+ /// Emit the llvm.used and llvm.compiler.used metadata.
+ void emitLLVMUsed();
/// \brief Emit the link options introduced by imported modules.
void EmitModuleLinkOptions();