From 4dc34ebf2a0716bf77ba110dab6777a3fc4397dd Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Sun, 20 May 2012 21:08:35 +0000
Subject: CUDA: add CodeGen support for global variable address spaces. Because
 in CUDA types do not have associated address spaces, globals are declared in
 their "native" address space, and accessed by bitcasting the pointer to
 address space 0.  This relies on address space 0 being a unified address
 space.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@157167 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CodeGenModule.cpp | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

(limited to 'lib/CodeGen/CodeGenModule.cpp')

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index f2dda5d658..0da493ffb5 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1172,11 +1172,12 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
     DeferredDecls.erase(DDI);
   }
 
+  unsigned AddrSpace = GetGlobalVarAddressSpace(D, Ty->getAddressSpace());
   llvm::GlobalVariable *GV =
     new llvm::GlobalVariable(getModule(), Ty->getElementType(), false,
                              llvm::GlobalValue::ExternalLinkage,
                              0, MangledName, 0,
-                             false, Ty->getAddressSpace());
+                             false, AddrSpace);
 
   // Handle things which are present even on external declarations.
   if (D) {
@@ -1202,7 +1203,10 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
     GV->setThreadLocal(D->isThreadSpecified());
   }
 
-  return GV;
+  if (AddrSpace != Ty->getAddressSpace())
+    return llvm::ConstantExpr::getBitCast(GV, Ty);
+  else
+    return GV;
 }
 
 
@@ -1487,6 +1491,20 @@ CodeGenModule::MaybeEmitGlobalStdInitializerListInitializer(const VarDecl *D,
   return llvmInit;
 }
 
+unsigned CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D,
+                                                 unsigned AddrSpace) {
+  if (LangOpts.CUDA && CodeGenOpts.CUDAIsDevice) {
+    if (D->hasAttr<CUDAConstantAttr>())
+      AddrSpace = getContext().getTargetAddressSpace(LangAS::cuda_constant);
+    else if (D->hasAttr<CUDASharedAttr>())
+      AddrSpace = getContext().getTargetAddressSpace(LangAS::cuda_shared);
+    else
+      AddrSpace = getContext().getTargetAddressSpace(LangAS::cuda_device);
+  }
+
+  return AddrSpace;
+}
+
 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   llvm::Constant *Init = 0;
   QualType ASTTy = D->getType();
@@ -1566,7 +1584,7 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   if (GV == 0 ||
       GV->getType()->getElementType() != InitType ||
       GV->getType()->getAddressSpace() !=
-        getContext().getTargetAddressSpace(ASTTy)) {
+       GetGlobalVarAddressSpace(D, getContext().getTargetAddressSpace(ASTTy))) {
 
     // Move the old entry aside so that we'll create a new one.
     Entry->setName(StringRef());
-- 
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