caio/clang-p2996
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Fix some layering violations where CGObjCMac's NSString emission was

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performed at the CodeGenModule level.

Would be NFC except we now also use a different uniquing structure so
that we don't get spurious conflicts if you ask for both an NSString
and a CFString for the same content (which is possible with builtins).

llvm-svn: 288287
This commit is contained in:
John McCall
2016-11-30 23:15:55 +00:00
parent 78a695321e
commit cd21d54139
3 changed files with 127 additions and 135 deletions
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133
clang/lib/CodeGen/CGObjCMac.cpp
View File

@@ -888,6 +888,15 @@ protected:
/// DefinedNonLazyCategories - List of defined "non-lazy" categories.
SmallVector<llvm::GlobalValue*, 16> DefinedNonLazyCategories;
/// Cached reference to the class for constant strings. This value has type
/// int * but is actually an Obj-C class pointer.
llvm::WeakVH ConstantStringClassRef;
/// \brief The LLVM type corresponding to NSConstantString.
llvm::StructType *NSConstantStringType = nullptr;
llvm::StringMap<llvm::GlobalVariable *> NSConstantStringMap;
/// GetNameForMethod - Return a name for the given method.
/// \param[out] NameOut - The return value.
void GetNameForMethod(const ObjCMethodDecl *OMD,
@@ -1054,6 +1063,7 @@ public:
}
ConstantAddress GenerateConstantString(const StringLiteral *SL) override;
ConstantAddress GenerateConstantNSString(const StringLiteral *SL);
llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD=nullptr) override;
@@ -1070,6 +1080,9 @@ public:
/// forward references will be filled in with empty bodies if no
/// definition is seen. The return value has type ProtocolPtrTy.
virtual llvm::Constant *GetOrEmitProtocolRef(const ObjCProtocolDecl *PD)=0;
virtual llvm::Constant *getNSConstantStringClassRef() = 0;
llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
const CGBlockInfo &blockInfo) override;
llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
@@ -1266,6 +1279,8 @@ private:
public:
CGObjCMac(CodeGen::CodeGenModule &cgm);
llvm::Constant *getNSConstantStringClassRef() override;
llvm::Function *ModuleInitFunction() override;
CodeGen::RValue GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
@@ -1536,7 +1551,9 @@ private:
public:
CGObjCNonFragileABIMac(CodeGen::CodeGenModule &cgm);
// FIXME. All stubs for now!
llvm::Constant *getNSConstantStringClassRef() override;
llvm::Function *ModuleInitFunction() override;
CodeGen::RValue GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
@@ -1846,11 +1863,115 @@ llvm::Constant *CGObjCMac::GetEHType(QualType T) {
};
*/
ConstantAddress CGObjCCommonMac::GenerateConstantString(
const StringLiteral *SL) {
return (CGM.getLangOpts().NoConstantCFStrings == 0 ?
CGM.GetAddrOfConstantCFString(SL) :
CGM.GetAddrOfConstantString(SL));
ConstantAddress
CGObjCCommonMac::GenerateConstantString(const StringLiteral *SL) {
return (!CGM.getLangOpts().NoConstantCFStrings
? CGM.GetAddrOfConstantCFString(SL)
: GenerateConstantNSString(SL));
}
static llvm::StringMapEntry<llvm::GlobalVariable *> &
GetConstantStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
const StringLiteral *Literal, unsigned &StringLength) {
StringRef String = Literal->getString();
StringLength = String.size();
return *Map.insert(std::make_pair(String, nullptr)).first;
}
llvm::Constant *CGObjCMac::getNSConstantStringClassRef() {
if (llvm::Value *V = ConstantStringClassRef)
return cast<llvm::Constant>(V);
auto &StringClass = CGM.getLangOpts().ObjCConstantStringClass;
std::string str =
StringClass.empty() ? "_NSConstantStringClassReference"
: "_" + StringClass + "ClassReference";
llvm::Type *PTy = llvm::ArrayType::get(CGM.IntTy, 0);
auto GV = CGM.CreateRuntimeVariable(PTy, str);
auto V = llvm::ConstantExpr::getBitCast(GV, CGM.IntTy->getPointerTo());
ConstantStringClassRef = V;
return V;
}
llvm::Constant *CGObjCNonFragileABIMac::getNSConstantStringClassRef() {
if (llvm::Value *V = ConstantStringClassRef)
return cast<llvm::Constant>(V);
auto &StringClass = CGM.getLangOpts().ObjCConstantStringClass;
std::string str =
StringClass.empty() ? "OBJC_CLASS_$_NSConstantString"
: "OBJC_CLASS_$_" + StringClass;
auto GV = GetClassGlobal(str);
// Make sure the result is of the correct type.
auto V = llvm::ConstantExpr::getBitCast(GV, CGM.IntTy->getPointerTo());
ConstantStringClassRef = V;
return V;
}
ConstantAddress
CGObjCCommonMac::GenerateConstantNSString(const StringLiteral *Literal) {
unsigned StringLength = 0;
llvm::StringMapEntry<llvm::GlobalVariable *> &Entry =
GetConstantStringEntry(NSConstantStringMap, Literal, StringLength);
if (auto *C = Entry.second)
return ConstantAddress(C, CharUnits::fromQuantity(C->getAlignment()));
// If we don't already have it, get _NSConstantStringClassReference.
llvm::Constant *Class = getNSConstantStringClassRef();
// If we don't already have it, construct the type for a constant NSString.
if (!NSConstantStringType) {
NSConstantStringType =
llvm::StructType::create({
CGM.Int32Ty->getPointerTo(),
CGM.Int8PtrTy,
CGM.IntTy
}, "struct.__builtin_NSString");
}
ConstantInitBuilder Builder(CGM);
auto Fields = Builder.beginStruct(NSConstantStringType);
// Class pointer.
Fields.add(Class);
// String pointer.
llvm::Constant *C =
llvm::ConstantDataArray::getString(VMContext, Entry.first());
llvm::GlobalValue::LinkageTypes Linkage = llvm::GlobalValue::PrivateLinkage;
bool isConstant = !CGM.getLangOpts().WritableStrings;
auto *GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(), isConstant,
Linkage, C, ".str");
GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
// Don't enforce the target's minimum global alignment, since the only use
// of the string is via this class initializer.
GV->setAlignment(1);
Fields.addBitCast(GV, CGM.Int8PtrTy);
// String length.
Fields.addInt(CGM.IntTy, StringLength);
// The struct.
CharUnits Alignment = CGM.getPointerAlign();
GV = Fields.finishAndCreateGlobal("_unnamed_nsstring_", Alignment,
/*constant*/ true,
llvm::GlobalVariable::PrivateLinkage);
const char *NSStringSection = "__OBJC,__cstring_object,regular,no_dead_strip";
const char *NSStringNonFragileABISection =
"__DATA,__objc_stringobj,regular,no_dead_strip";
// FIXME. Fix section.
GV->setSection(CGM.getLangOpts().ObjCRuntime.isNonFragile()
? NSStringNonFragileABISection
: NSStringSection);
Entry.second = GV;
return ConstantAddress(GV, Alignment);
}
enum {

122
clang/lib/CodeGen/CodeGenModule.cpp
View File

@@ -3131,14 +3131,6 @@ GetConstantCFStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
nullptr)).first;
}
static llvm::StringMapEntry<llvm::GlobalVariable *> &
GetConstantStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
const StringLiteral *Literal, unsigned &StringLength) {
StringRef String = Literal->getString();
StringLength = String.size();
return *Map.insert(std::make_pair(String, nullptr)).first;
}
ConstantAddress
CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
unsigned StringLength = 0;
@@ -3265,120 +3257,6 @@ CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
return ConstantAddress(GV, Alignment);
}
ConstantAddress
CodeGenModule::GetAddrOfConstantString(const StringLiteral *Literal) {
unsigned StringLength = 0;
llvm::StringMapEntry<llvm::GlobalVariable *> &Entry =
GetConstantStringEntry(CFConstantStringMap, Literal, StringLength);
if (auto *C = Entry.second)
return ConstantAddress(C, CharUnits::fromQuantity(C->getAlignment()));
llvm::Constant *Zero = llvm::Constant::getNullValue(Int32Ty);
llvm::Constant *Zeros[] = { Zero, Zero };
llvm::Value *V;
// If we don't already have it, get _NSConstantStringClassReference.
if (!ConstantStringClassRef) {
std::string StringClass(getLangOpts().ObjCConstantStringClass);
llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
llvm::Constant *GV;
if (LangOpts.ObjCRuntime.isNonFragile()) {
std::string str =
StringClass.empty() ? "OBJC_CLASS_$_NSConstantString"
: "OBJC_CLASS_$_" + StringClass;
GV = getObjCRuntime().GetClassGlobal(str);
// Make sure the result is of the correct type.
llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
V = llvm::ConstantExpr::getBitCast(GV, PTy);
ConstantStringClassRef = V;
} else {
std::string str =
StringClass.empty() ? "_NSConstantStringClassReference"
: "_" + StringClass + "ClassReference";
llvm::Type *PTy = llvm::ArrayType::get(Ty, 0);
GV = CreateRuntimeVariable(PTy, str);
// Decay array -> ptr
V = llvm::ConstantExpr::getGetElementPtr(PTy, GV, Zeros);
ConstantStringClassRef = V;
}
} else
V = ConstantStringClassRef;
if (!NSConstantStringType) {
// Construct the type for a constant NSString.
RecordDecl *D = Context.buildImplicitRecord("__builtin_NSString");
D->startDefinition();
QualType FieldTypes[3];
// const int *isa;
FieldTypes[0] = Context.getPointerType(Context.IntTy.withConst());
// const char *str;
FieldTypes[1] = Context.getPointerType(Context.CharTy.withConst());
// unsigned int length;
FieldTypes[2] = Context.UnsignedIntTy;
// Create fields
for (unsigned i = 0; i < 3; ++i) {
FieldDecl *Field = FieldDecl::Create(Context, D,
SourceLocation(),
SourceLocation(), nullptr,
FieldTypes[i], /*TInfo=*/nullptr,
/*BitWidth=*/nullptr,
/*Mutable=*/false,
ICIS_NoInit);
Field->setAccess(AS_public);
D->addDecl(Field);
}
D->completeDefinition();
QualType NSTy = Context.getTagDeclType(D);
NSConstantStringType = cast<llvm::StructType>(getTypes().ConvertType(NSTy));
}
ConstantInitBuilder Builder(*this);
auto Fields = Builder.beginStruct(NSConstantStringType);
// Class pointer.
Fields.add(cast<llvm::ConstantExpr>(V));
// String pointer.
llvm::Constant *C =
llvm::ConstantDataArray::getString(VMContext, Entry.first());
llvm::GlobalValue::LinkageTypes Linkage = llvm::GlobalValue::PrivateLinkage;
bool isConstant = !LangOpts.WritableStrings;
auto *GV = new llvm::GlobalVariable(getModule(), C->getType(), isConstant,
Linkage, C, ".str");
GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
// Don't enforce the target's minimum global alignment, since the only use
// of the string is via this class initializer.
CharUnits Align = getContext().getTypeAlignInChars(getContext().CharTy);
GV->setAlignment(Align.getQuantity());
Fields.add(
llvm::ConstantExpr::getGetElementPtr(GV->getValueType(), GV, Zeros));
// String length.
Fields.addInt(IntTy, StringLength);
// The struct.
CharUnits Alignment = getPointerAlign();
GV = Fields.finishAndCreateGlobal("_unnamed_nsstring_", Alignment,
/*constant*/ true,
llvm::GlobalVariable::PrivateLinkage);
const char *NSStringSection = "__OBJC,__cstring_object,regular,no_dead_strip";
const char *NSStringNonFragileABISection =
"__DATA,__objc_stringobj,regular,no_dead_strip";
// FIXME. Fix section.
GV->setSection(LangOpts.ObjCRuntime.isNonFragile()
? NSStringNonFragileABISection
: NSStringSection);
Entry.second = GV;
return ConstantAddress(GV, Alignment);
}
QualType CodeGenModule::getObjCFastEnumerationStateType() {
if (ObjCFastEnumerationStateType.isNull()) {
RecordDecl *D = Context.buildImplicitRecord("__objcFastEnumerationState");

7
clang/lib/CodeGen/CodeGenModule.h
View File

@@ -434,13 +434,6 @@ private:
/// int * but is actually an Obj-C class pointer.
llvm::WeakVH CFConstantStringClassRef;
/// Cached reference to the class for constant strings. This value has type
/// int * but is actually an Obj-C class pointer.
llvm::WeakVH ConstantStringClassRef;
/// \brief The LLVM type corresponding to NSConstantString.
llvm::StructType *NSConstantStringType = nullptr;
/// \brief The type used to describe the state of a fast enumeration in
/// Objective-C's for..in loop.
QualType ObjCFastEnumerationStateType;