[HIP] Fix visibility of `__constant__` variables.

[hliao]

Summary

• __constant__ variables should not be hidden as the linker may turn them into LOCAL symbols.

[yaxunl]

clang/lib/CodeGen/TargetInfo.cpp

7851 ↗

(On Diff #196857)

is format right?

clang/test/CodeGenCUDA/amdgpu-visibility.cu

1 ↗

(On Diff #196857)

do we need -fapply-global-visibility-to-externs?

[hliao]

clang/lib/CodeGen/TargetInfo.cpp

7851 ↗

(On Diff #196857)

yeah, it's the format after clang-format. It seems that clang-format try to apply the same indent for LHS & RHS of a binary operator. With the leading parenthesis, RHS in a newline is indented with one more space.

[hliao]

clang/test/CodeGenCUDA/amdgpu-visibility.cu

1 ↗

(On Diff #196857)

that's so far the option applied for both AMDGPU & HIP (targetting non-MS) by default in clang frontend. Check AMDGPUToolChain::addClangTargetOptions and HIPToolChain::addClangTargetOptions

[yaxunl]

LGTM. Thanks!

lib/CodeGen/TargetInfo.cpp

 
 static bool requiresAMDGPUProtectedVisibility(const Decl *D,
                                               llvm::GlobalValue *GV) {
   if (GV->getVisibility() != llvm::GlobalValue::HiddenVisibility)
     return false;
 
   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(
     const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &M) const {
   if (requiresAMDGPUProtectedVisibility(D, GV)) {
     GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
     GV->setDSOLocal(true);
   }

test/CodeGenCUDA/amdgpu-visibility.cu

+// 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;
+}