CodeGen: Emit string literal in constant address space
Some targets have constant address space (e.g. amdgcn). For them string literal should be
emitted in constant address space then casted to default address space.
Differential Revision: https://reviews.llvm.org/D46643
llvm-svn: 332279
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 3a27d99..50b653c 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3044,6 +3044,39 @@
return getTargetCodeGenInfo().getGlobalVarAddressSpace(*this, D);
}
+LangAS CodeGenModule::getStringLiteralAddressSpace() const {
+ // OpenCL v1.2 s6.5.3: a string literal is in the constant address space.
+ if (LangOpts.OpenCL)
+ return LangAS::opencl_constant;
+ if (auto AS = getTarget().getConstantAddressSpace())
+ return AS.getValue();
+ return LangAS::Default;
+}
+
+// In address space agnostic languages, string literals are in default address
+// space in AST. However, certain targets (e.g. amdgcn) request them to be
+// emitted in constant address space in LLVM IR. To be consistent with other
+// parts of AST, string literal global variables in constant address space
+// need to be casted to default address space before being put into address
+// map and referenced by other part of CodeGen.
+// In OpenCL, string literals are in constant address space in AST, therefore
+// they should not be casted to default address space.
+static llvm::Constant *
+castStringLiteralToDefaultAddressSpace(CodeGenModule &CGM,
+ llvm::GlobalVariable *GV) {
+ llvm::Constant *Cast = GV;
+ if (!CGM.getLangOpts().OpenCL) {
+ if (auto AS = CGM.getTarget().getConstantAddressSpace()) {
+ if (AS != LangAS::Default)
+ Cast = CGM.getTargetCodeGenInfo().performAddrSpaceCast(
+ CGM, GV, AS.getValue(), LangAS::Default,
+ GV->getValueType()->getPointerTo(
+ CGM.getContext().getTargetAddressSpace(LangAS::Default)));
+ }
+ }
+ return Cast;
+}
+
template<typename SomeDecl>
void CodeGenModule::MaybeHandleStaticInExternC(const SomeDecl *D,
llvm::GlobalValue *GV) {
@@ -4039,10 +4072,8 @@
GenerateStringLiteral(llvm::Constant *C, llvm::GlobalValue::LinkageTypes LT,
CodeGenModule &CGM, StringRef GlobalName,
CharUnits Alignment) {
- // OpenCL v1.2 s6.5.3: a string literal is in the constant address space.
- unsigned AddrSpace = 0;
- if (CGM.getLangOpts().OpenCL)
- AddrSpace = CGM.getContext().getTargetAddressSpace(LangAS::opencl_constant);
+ unsigned AddrSpace = CGM.getContext().getTargetAddressSpace(
+ CGM.getStringLiteralAddressSpace());
llvm::Module &M = CGM.getModule();
// Create a global variable for this string
@@ -4104,7 +4135,9 @@
SanitizerMD->reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>",
QualType());
- return ConstantAddress(GV, Alignment);
+
+ return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
+ Alignment);
}
/// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
@@ -4148,7 +4181,9 @@
GlobalName, Alignment);
if (Entry)
*Entry = GV;
- return ConstantAddress(GV, Alignment);
+
+ return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
+ Alignment);
}
ConstantAddress CodeGenModule::GetAddrOfGlobalTemporary(