[HIP] Fix visibility of `__constant__` variables.

Summary:
- `__constant__` variables should not be `hidden` as the linker may turn
  them into `LOCAL` symbols.

Reviewers: yaxunl

Subscribers: jvesely, nhaehnle, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61194

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@359344 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/TargetInfo.cpp

@@ -7847,7 +7847,8 @@ static bool requiresAMDGPUProtectedVisibility(const Decl *D,
 
   return D->hasAttr<OpenCLKernelAttr>() ||
          (isa<FunctionDecl>(D) && D->hasAttr<CUDAGlobalAttr>()) ||
-         (isa<VarDecl>(D) && D->hasAttr<CUDADeviceAttr>());
+         (isa<VarDecl>(D) &&
+          (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>()));
 }
 
 void AMDGPUTargetCodeGenInfo::setTargetAttributes(

test/CodeGenCUDA/amdgpu-visibility.cu

@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -fcuda-is-device -fapply-global-visibility-to-externs -fvisibility default -emit-llvm -o - %s | FileCheck --check-prefix=CHECK-DEFAULT %s
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -fcuda-is-device -fapply-global-visibility-to-externs -fvisibility protected -emit-llvm -o - %s | FileCheck --check-prefix=CHECK-PROTECTED %s
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa -fcuda-is-device -fapply-global-visibility-to-externs -fvisibility hidden -emit-llvm -o - %s | FileCheck --check-prefix=CHECK-HIDDEN %s
+
+#include "Inputs/cuda.h"
+
+// CHECK-DEFAULT: @c = addrspace(4) externally_initialized global
+// CHECK-DEFAULT: @g = addrspace(1) externally_initialized global
+// CHECK-PROTECTED: @c = protected addrspace(4) externally_initialized global
+// CHECK-PROTECTED: @g = protected addrspace(1) externally_initialized global
+// CHECK-HIDDEN: @c = protected addrspace(4) externally_initialized global
+// CHECK-HIDDEN: @g = protected addrspace(1) externally_initialized global
+__constant__ int c;
+__device__ int g;
+
+// CHECK-DEFAULT: define amdgpu_kernel void @_Z3foov()
+// CHECK-PROTECTED: define protected amdgpu_kernel void @_Z3foov()
+// CHECK-HIDDEN: define protected amdgpu_kernel void @_Z3foov()
+__global__ void foo() {
+  g = c;
+}