[InstrProf] Mark __llvm_profile_runtime hidden to match libclang_rt.profile definition

[justincady]

Summary

Mark the symbol hidden to match INSTR_PROF_PROFILE_RUNTIME_VAR in compiler-rt.

Fixes second issue discussed at https://discourse.llvm.org/t/63090

[MaskRay]

This change does not mark the symbol hidden on Windows to match libclang_rt.profile's default visibility for Windows targets.

Just drop the special case.

This change looks good to me because of COMPILER_RT_VISIBILITY extern int INSTR_PROF_PROFILE_RUNTIME_VAR;

llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp

1247

Remove Windows special case. The visibility is a no-op on Windows.

[justincady]

Remove special case for Windows based on MaskRay's comment.

[justincady]

llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp

1247

Done, thank you. I was trying to match COMPILER_RT_VISIBILITY not setting visibility for Windows, but did not realize it isn't set because it's a no-op.

[justincady]

@MaskRay Does this change require any further review? If it is good to go, would you please land it for me? I don't have commit access.

Thanks!

llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp

bool InstrProfiling::emitRuntimeHook() {
   if (M->getGlobalVariable(getInstrProfRuntimeHookVarName()))
     return false;
 
   // Declare an external variable that will pull in the runtime initialization.
   auto *Int32Ty = Type::getInt32Ty(M->getContext());
   auto *Var =
       new GlobalVariable(*M, Int32Ty, false, GlobalValue::ExternalLinkage,
                          nullptr, getInstrProfRuntimeHookVarName());
+  Var->setVisibility(GlobalValue::HiddenVisibility);
 
   if (TT.isOSBinFormatELF() && !TT.isPS()) {
     // Mark the user variable as used so that it isn't stripped out.
     CompilerUsedVars.push_back(Var);
   } else {
     // Make a function that uses it.
     auto *User = Function::Create(FunctionType::get(Int32Ty, false),
                                   GlobalValue::LinkOnceODRLinkage,

llvm/test/Instrumentation/InstrProfiling/profiling.ll

 ;; Test runtime symbols and various linkages.
 
 ; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -passes=instrprof -S | FileCheck %s --check-prefixes=MACHO
 ; RUN: opt < %s -mtriple=x86_64 -passes=instrprof -S | FileCheck %s --check-prefix=ELF_GENERIC
 ; RUN: opt < %s -mtriple=x86_64-unknown-linux -passes=instrprof -S | FileCheck %s --check-prefixes=ELF,ELFRT
 ; RUN: opt < %s -mtriple=x86_64-unknown-fuchsia -passes=instrprof -S | FileCheck %s --check-prefixes=ELF,ELFRT
 ; RUN: opt < %s -mtriple=x86_64-scei-ps4 -passes=instrprof -S | FileCheck %s --check-prefixes=ELF,PS
 ; RUN: opt < %s -mtriple=x86_64-sie-ps5 -passes=instrprof -S | FileCheck %s --check-prefixes=ELF,PS
 ; RUN: opt < %s  -mtriple=x86_64-pc-win32-coff -passes=instrprof -S | FileCheck %s --check-prefixes=COFF
 ; RUN: opt < %s -mtriple=powerpc64-ibm-aix-xcoff -passes=instrprof -S | FileCheck %s --check-prefixes=XCOFF
+; RUN: opt < %s -mtriple=x86_64-pc-freebsd13 -passes=instrprof -S | FileCheck %s --check-prefixes=ELF
 
-; MACHO: @__llvm_profile_runtime = external global i32
-; ELF_GENERIC: @__llvm_profile_runtime = external global i32
+; MACHO: @__llvm_profile_runtime = external hidden global i32
+; ELF_GENERIC: @__llvm_profile_runtime = external hidden global i32
 ; ELF-NOT: @__llvm_profile_runtime = external global i32
-; XCOFF: @__llvm_profile_runtime = external global i32
+; XCOFF: @__llvm_profile_runtime = external hidden global i32
+; COFF: @__llvm_profile_runtime = external hidden global i32
 
 ; ELF: $__profc_foo = comdat nodeduplicate
 ; ELF: $__profc_foo_weak = comdat nodeduplicate
 ; ELF: $"__profc_linkage.ll:foo_internal" = comdat nodeduplicate
 ; ELF: $__profc_foo_inline = comdat nodeduplicate
 ; ELF: $__profc_foo_extern = comdat any
 
 @__profn_foo = private constant [3 x i8] c"foo"