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/CGExpr.cpp

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 2ee1c96..9f40ee5 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -338,9 +338,10 @@
   }
 }
 
-static Address
-createReferenceTemporary(CodeGenFunction &CGF,
-                         const MaterializeTemporaryExpr *M, const Expr *Inner) {
+static Address createReferenceTemporary(CodeGenFunction &CGF,
+                                        const MaterializeTemporaryExpr *M,
+                                        const Expr *Inner) {
+  auto &TCG = CGF.getTargetHooks();
   switch (M->getStorageDuration()) {
   case SD_FullExpression:
   case SD_Automatic: {
@@ -353,13 +354,24 @@
         (Ty->isArrayType() || Ty->isRecordType()) &&
         CGF.CGM.isTypeConstant(Ty, true))
       if (llvm::Constant *Init = CGF.CGM.EmitConstantExpr(Inner, Ty, &CGF)) {
-        auto *GV = new llvm::GlobalVariable(
-            CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
-            llvm::GlobalValue::PrivateLinkage, Init, ".ref.tmp");
-        CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty);
-        GV->setAlignment(alignment.getQuantity());
-        // FIXME: Should we put the new global into a COMDAT?
-        return Address(GV, alignment);
+        if (auto AddrSpace = CGF.getTarget().getConstantAddressSpace()) {
+          auto AS = AddrSpace.getValue();
+          auto *GV = new llvm::GlobalVariable(
+              CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
+              llvm::GlobalValue::PrivateLinkage, Init, ".ref.tmp", nullptr,
+              llvm::GlobalValue::NotThreadLocal,
+              CGF.getContext().getTargetAddressSpace(AS));
+          CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty);
+          GV->setAlignment(alignment.getQuantity());
+          llvm::Constant *C = GV;
+          if (AS != LangAS::Default)
+            C = TCG.performAddrSpaceCast(
+                CGF.CGM, GV, AS, LangAS::Default,
+                GV->getValueType()->getPointerTo(
+                    CGF.getContext().getTargetAddressSpace(LangAS::Default)));
+          // FIXME: Should we put the new global into a COMDAT?
+          return Address(C, alignment);
+        }
       }
     return CGF.CreateMemTemp(Ty, "ref.tmp");
   }
@@ -440,9 +452,11 @@
 
   // Create and initialize the reference temporary.
   Address Object = createReferenceTemporary(*this, M, E);
-  if (auto *Var = dyn_cast<llvm::GlobalVariable>(Object.getPointer())) {
+  if (auto *Var = dyn_cast<llvm::GlobalVariable>(
+          Object.getPointer()->stripPointerCasts())) {
     Object = Address(llvm::ConstantExpr::getBitCast(
-        Var, ConvertTypeForMem(E->getType())->getPointerTo()),
+                         cast<llvm::Constant>(Object.getPointer()),
+                         ConvertTypeForMem(E->getType())->getPointerTo()),
                      Object.getAlignment());
     // If the temporary is a global and has a constant initializer or is a
     // constant temporary that we promoted to a global, we may have already