[cuda] treat file scope __asm as __host__ and ignore it during device-side compilation.

Currently clang emits file-scope asm during *both* host and device
compilation modes which is usually a wrong thing to do.

There's no way to attach any attribute to an __asm statement, so
there's no way to differentiate between host-side and device-side
file-scope asm.  This patch makes clang to match nvcc behavior and
emit file-scope-asm only during host-side compilation.

Differential Revision: http://reviews.llvm.org/D9270

llvm-svn: 235905

2 files changed, 9 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index b30885d4cdb..c517d17666d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3356,6 +3356,9 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
     break;
 
   case Decl::FileScopeAsm: {
+    // File-scope asm is ignored during device-side CUDA compilation.
+    if (LangOpts.CUDA && LangOpts.CUDAIsDevice)
+      break;
     auto *AD = cast<FileScopeAsmDecl>(D);
     getModule().appendModuleInlineAsm(AD->getAsmString()->getString());
     break;
diff --git a/clang/test/CodeGenCUDA/filter-decl.cu b/clang/test/CodeGenCUDA/filter-decl.cu
index faaeb69fe1c..e69473f3e84 100644
--- a/clang/test/CodeGenCUDA/filter-decl.cu
+++ b/clang/test/CodeGenCUDA/filter-decl.cu
@@ -3,6 +3,12 @@
 
 #include "Inputs/cuda.h"
 
+// This has to be at the top of the file as that's where file-scope
+// asm ends up.
+// CHECK-HOST: module asm "file scope asm is host only"
+// CHECK-DEVICE-NOT: module asm "file scope asm is host only"
+__asm__("file scope asm is host only");
+
 // CHECK-HOST-NOT: constantdata = global
 // CHECK-DEVICE: constantdata = global
 __constant__ char constantdata[256];