commit cbf647cc3a712ada34fcd78f7d39756193f323d2
author Yaxun Liu <Yaxun.Liu@amd.com> Sat Jul 08 13:24:52 2017 +0000
committer Yaxun Liu <Yaxun.Liu@amd.com> Sat Jul 08 13:24:52 2017 +0000
tree 7122745644a399b3aa8ac176c4fea1c9064462d5
parent affab3047e777ab69e09d18d23e8e7748b86b728

CodeGen: Fix address space of global variable

Certain targets (e.g. amdgcn) require global variable to stay in global or constant address
space. In C or C++ global variables are emitted in the default (generic) address space.
This patch introduces virtual functions TargetCodeGenInfo::getGlobalVarAddressSpace
and TargetInfo::getConstantAddressSpace to handle this in a general approach.

It only affects IR generated for amdgcn target.

Differential Revision: https://reviews.llvm.org/D33842

llvm-svn: 307470

clang/lib/CodeGen/TargetInfo.cpp

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 8d00e05..faec994 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -416,14 +416,33 @@
   return llvm::ConstantPointerNull::get(T);
 }
 
+unsigned TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
+                                                     const VarDecl *D) const {
+  assert(!CGM.getLangOpts().OpenCL &&
+         !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
+         "Address space agnostic languages only");
+  return D ? D->getType().getAddressSpace() : LangAS::Default;
+}
+
 llvm::Value *TargetCodeGenInfo::performAddrSpaceCast(
     CodeGen::CodeGenFunction &CGF, llvm::Value *Src, unsigned SrcAddr,
     unsigned DestAddr, llvm::Type *DestTy, bool isNonNull) const {
   // Since target may map different address spaces in AST to the same address
   // space, an address space conversion may end up as a bitcast.
+  if (auto *C = dyn_cast<llvm::Constant>(Src))
+    return performAddrSpaceCast(CGF.CGM, C, SrcAddr, DestAddr, DestTy);
   return CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(Src, DestTy);
 }
 
+llvm::Constant *
+TargetCodeGenInfo::performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *Src,
+                                        unsigned SrcAddr, unsigned DestAddr,
+                                        llvm::Type *DestTy) const {
+  // Since target may map different address spaces in AST to the same address
+  // space, an address space conversion may end up as a bitcast.
+  return llvm::ConstantExpr::getPointerCast(Src, DestTy);
+}
+
 static bool isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays);
 
 /// isEmptyField - Return true iff a the field is "empty", that is it
@@ -7325,6 +7344,8 @@
     return LangAS::FirstTargetAddressSpace +
            getABIInfo().getDataLayout().getAllocaAddrSpace();
   }
+  unsigned getGlobalVarAddressSpace(CodeGenModule &CGM,
+                                    const VarDecl *D) const override;
 };
 }
 
@@ -7408,6 +7429,31 @@
       llvm::ConstantPointerNull::get(NPT), PT);
 }
 
+unsigned
+AMDGPUTargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
+                                                  const VarDecl *D) const {
+  assert(!CGM.getLangOpts().OpenCL &&
+         !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
+         "Address space agnostic languages only");
+  unsigned DefaultGlobalAS =
+      LangAS::FirstTargetAddressSpace +
+      CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
+  if (!D)
+    return DefaultGlobalAS;
+
+  unsigned AddrSpace = D->getType().getAddressSpace();
+  assert(AddrSpace == LangAS::Default ||
+         AddrSpace >= LangAS::FirstTargetAddressSpace);
+  if (AddrSpace != LangAS::Default)
+    return AddrSpace;
+
+  if (CGM.isTypeConstant(D->getType(), false)) {
+    if (auto ConstAS = CGM.getTarget().getConstantAddressSpace())
+      return ConstAS.getValue();
+  }
+  return DefaultGlobalAS;
+}
+
 //===----------------------------------------------------------------------===//
 // SPARC v8 ABI Implementation.
 // Based on the SPARC Compliance Definition version 2.4.1.