Commit cac06860 authored by hsmahesha's avatar hsmahesha
Browse files

[HIP] Make sure, unused hip-pinned-shadow global var is kept within device code 

Summary:
hip-pinned-shadow global var should remain in the final code object irrespective
of whether it is used or not within the code. Add it to used list, so that it
will not get eliminated when it is unused.

Reviewers: yaxunl, tra, hliao

Reviewed By: yaxunl

Subscribers: hliao, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D75402
parent 952ad470

clang/lib/CodeGen/CodeGenModule.cpp

+13 −5
Original line number Diff line number Diff line
@@ -1916,9 +1916,9 @@ void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F, 
  }

}



void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV) {

  assert(!GV->isDeclaration() &&

         "Only globals with definition can force usage.");

void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV, bool SkipCheck) {

  assert(SkipCheck || (!GV->isDeclaration() &&

                       "Only globals with definition can force usage."));

  LLVMUsed.emplace_back(GV);

}
@@ -4071,9 +4071,17 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D, 
    }

  }



  if (!IsHIPPinnedShadowVar)

  // HIPPinnedShadowVar should remain in the final code object irrespective of

  // whether it is used or not within the code. Add it to used list, so that

  // it will not get eliminated when it is unused. Also, it is an extern var

  // within device code, and it should *not* get initialized within device code.

  if (IsHIPPinnedShadowVar)

    addUsedGlobal(GV, /*SkipCheck=*/true);

  else

    GV->setInitializer(Init);

  if (emitter) emitter->finalize(GV);



  if (emitter)

    emitter->finalize(GV);



  // If it is safe to mark the global 'constant', do so now.

  GV->setConstant(!NeedsGlobalCtor && !NeedsGlobalDtor &&

clang/lib/CodeGen/CodeGenModule.h

+1 −1
Original line number Diff line number Diff line
@@ -1037,7 +1037,7 @@ public: 
  void MaybeHandleStaticInExternC(const SomeDecl *D, llvm::GlobalValue *GV);



  /// Add a global to a list to be added to the llvm.used metadata.

  void addUsedGlobal(llvm::GlobalValue *GV);

  void addUsedGlobal(llvm::GlobalValue *GV, bool SkipCheck = false);



  /// Add a global to a list to be added to the llvm.compiler.used metadata.

  void addCompilerUsedGlobal(llvm::GlobalValue *GV);

clang/test/CodeGenCUDA/hip-pinned-shadow.cu

+4 −0
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ 
// RUN:     -emit-llvm -o - -x hip %s | FileCheck -check-prefixes=HIPDEV %s

// RUN: %clang_cc1 -triple x86_64 -std=c++11 \

// RUN:     -emit-llvm -o - -x hip %s | FileCheck -check-prefixes=HIPHOST %s

// RUN: %clang_cc1 -triple amdgcn -fcuda-is-device -std=c++11 -fvisibility hidden -fapply-global-visibility-to-externs \

// RUN:     -O3 -emit-llvm -o - -x hip %s | FileCheck -check-prefixes=HIPDEVUNSED %s



struct textureReference {

  int a;
@@ -21,3 +23,5 @@ __attribute__((hip_pinned_shadow)) texture<float, 2, 1> tex; 
// HIPDEV-NOT: declare{{.*}}void @_ZN7textureIfLi2ELi1EEC1Ev

// HIPHOST:  define{{.*}}@_ZN7textureIfLi2ELi1EEC1Ev

// HIPHOST:  call i32 @__hipRegisterVar{{.*}}@tex{{.*}}i32 0, i32 4, i32 0, i32 0)

// HIPDEVUNSED: @tex = external addrspace(1) global %struct.texture

// HIPDEVUNSED-NOT: declare{{.*}}void @_ZN7textureIfLi2ELi1EEC1Ev