CodeGen: Cast alloca to expected address space

Alloca always returns a pointer in alloca address space, which may
be different from the type defined by the language. For example,
in C++ the auto variables are in the default address space. Therefore
cast alloca to the expected address space when necessary.

Differential Revision: https://reviews.llvm.org/D32248

llvm-svn: 303370

1 files changed, 17 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 0fa8eeb1c3e..d6abfa15e54 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -11,14 +11,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "CodeGenFunction.h"
 #include "CGBlocks.h"
 #include "CGCXXABI.h"
 #include "CGCleanup.h"
 #include "CGDebugInfo.h"
 #include "CGOpenCLRuntime.h"
 #include "CGOpenMPRuntime.h"
+#include "CodeGenFunction.h"
 #include "CodeGenModule.h"
+#include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/CharUnits.h"
 #include "clang/AST/Decl.h"
@@ -1105,6 +1106,21 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
     address = Address(vla, alignment);
   }
 
+  // Alloca always returns a pointer in alloca address space, which may
+  // be different from the type defined by the language. For example,
+  // in C++ the auto variables are in the default address space. Therefore
+  // cast alloca to the expected address space when necessary.
+  auto T = D.getType();
+  assert(T.getAddressSpace() == LangAS::Default);
+  if (getASTAllocaAddressSpace() != LangAS::Default) {
+    auto *Addr = getTargetHooks().performAddrSpaceCast(
+        *this, address.getPointer(), getASTAllocaAddressSpace(),
+        T.getAddressSpace(),
+        address.getElementType()->getPointerTo(
+            getContext().getTargetAddressSpace(T.getAddressSpace())),
+        /*non-null*/ true);
+    address = Address(Addr, address.getAlignment());
+  }
   setAddrOfLocalVar(&D, address);
   emission.Addr = address;