From: Artem Belevich <tra@google.com>
Date: Wed, 23 Sep 2015 17:44:53 +0000 (+0000)
Subject: [CUDA] __global__ functions should always be visible externally.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b7a9667a4192f47243f2fc4bb2665d421c3d52ad;p=clang

[CUDA] __global__ functions should always be visible externally.

Adjust __global__ functions with DiscardableODR linkage to use
StrongODR linkage instead, so they are visible externally.

Differential Revision: http://reviews.llvm.org/D13067

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@248400 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index b98e3d4ed9..85add92792 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -8284,13 +8284,13 @@ static GVALinkage basicGVALinkageForFunction(const ASTContext &Context,
   return GVA_DiscardableODR;
 }
 
-static GVALinkage adjustGVALinkageForDLLAttribute(GVALinkage L, const Decl *D) {
+static GVALinkage adjustGVALinkageForAttributes(GVALinkage L, const Decl *D) {
   // See http://msdn.microsoft.com/en-us/library/xa0d9ste.aspx
   // dllexport/dllimport on inline functions.
   if (D->hasAttr<DLLImportAttr>()) {
     if (L == GVA_DiscardableODR || L == GVA_StrongODR)
       return GVA_AvailableExternally;
-  } else if (D->hasAttr<DLLExportAttr>()) {
+  } else if (D->hasAttr<DLLExportAttr>() || D->hasAttr<CUDAGlobalAttr>()) {
     if (L == GVA_DiscardableODR)
       return GVA_StrongODR;
   }
@@ -8298,8 +8298,8 @@ static GVALinkage adjustGVALinkageForDLLAttribute(GVALinkage L, const Decl *D) {
 }
 
 GVALinkage ASTContext::GetGVALinkageForFunction(const FunctionDecl *FD) const {
-  return adjustGVALinkageForDLLAttribute(basicGVALinkageForFunction(*this, FD),
-                                         FD);
+  return adjustGVALinkageForAttributes(basicGVALinkageForFunction(*this, FD),
+                                       FD);
 }
 
 static GVALinkage basicGVALinkageForVariable(const ASTContext &Context,
@@ -8355,8 +8355,8 @@ static GVALinkage basicGVALinkageForVariable(const ASTContext &Context,
 }
 
 GVALinkage ASTContext::GetGVALinkageForVariable(const VarDecl *VD) {
-  return adjustGVALinkageForDLLAttribute(basicGVALinkageForVariable(*this, VD),
-                                         VD);
+  return adjustGVALinkageForAttributes(basicGVALinkageForVariable(*this, VD),
+                                       VD);
 }
 
 bool ASTContext::DeclMustBeEmitted(const Decl *D) {
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index ddf189ae12..9cc082152b 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -3351,9 +3351,6 @@ static void handleGlobalAttr(Sema &S, Decl *D, const AttributeList &Attr) {
               CUDAGlobalAttr(Attr.getRange(), S.Context,
                              Attr.getAttributeSpellingListIndex()));
 
-  // Add implicit attribute((used)) so we don't eliminate kernels
-  // because there is nothing referencing them on device side.
-  D->addAttr(UsedAttr::CreateImplicit(S.Context));
 }
 
 static void handleGNUInlineAttr(Sema &S, Decl *D, const AttributeList &Attr) {
diff --git a/test/CodeGenCUDA/ptx-kernels.cu b/test/CodeGenCUDA/ptx-kernels.cu
index 3a8722a342..6280e604f2 100644
--- a/test/CodeGenCUDA/ptx-kernels.cu
+++ b/test/CodeGenCUDA/ptx-kernels.cu
@@ -6,11 +6,6 @@
 
 #include "Inputs/cuda.h"
 
-// Make sure that all __global__ functions are added to @llvm.used
-// CHECK: @llvm.used = appending global
-// CHECK-SAME: @global_function
-// CHECK-SAME: @_Z16templated_kernelIiEvT_
-
 // CHECK-LABEL: define void @device_function
 extern "C"
 __device__ void device_function() {}
@@ -24,7 +19,7 @@ __global__ void global_function() {
 
 // Make sure host-instantiated kernels are preserved on device side.
 template <typename T> __global__ void templated_kernel(T param) {}
-// CHECK-LABEL: define linkonce_odr void @_Z16templated_kernelIiEvT_
+// CHECK-LABEL: define weak_odr void @_Z16templated_kernelIiEvT_
 void host_function() { templated_kernel<<<0,0>>>(0); }
 
 // CHECK: !{{[0-9]+}} = !{void ()* @global_function, !"kernel", i32 1}