[PGO] Make emitted symbols hidden

[abrachet]

Summary

This was reverted because it was breaking when targeting Darwin which
tried to export these symbols which are now hidden. It should be safe
to just stop attempting to export these symbols in the clang driver,
though Apple folks will need to change their TAPI allow list described
in the commit where these symbols were originally exported
https://github.com/llvm/llvm-project/commit/f5380185623be243ba0f1b18d4bd594ac5cc7163

Bug: https://github.com/llvm/llvm-project/issues/58265

[MaskRay]

I think __llvm_profile_raw_version can be made hidden but can you state the motivation?

[davidxl]

Is it due to the mixing instrumented shared libraries built with different compiler and profile versions?

[abrachet]

It's just not necessary for these symbols to have default visibility. and its preferable that the compiler expose as few implementation details as possible. We track the abi's of our shared objects closely with llvm-ifs and were surprised to find these symbols publicly exposed

[mcgrathr]

lgtm

[MaskRay]

The subject should change the emitted symbol to __llvm_profile_raw_version.

[mcgrathr]

In D135340#3840704, @MaskRay wrote:

The subject should change the emitted symbol to __llvm_profile_raw_version.

This change affects __llvm_profile_raw_version and __llvm_profile_filename.
The invariant that should be maintained is that *all* symbols this instrumentation injects should have hidden visibility (if they're not local).

[delcypher]

This definitely needs some more eyes from Apple engineers. Unfortunately @vsk isn't too active on this part of the compiler anymore. I don't work on PGO myself or TAPI so I can't approve this change. I've added @arphaman and @cishida who might have opinions here.

[cishida]

This change LGTM. My understanding of the history here, is that these symbols were exported expecting to be eventually referenced when profiling options are used but weren't always consistently exported. This kind of inconsistency of symbol exports breaks TAPI verification. In the recent past we've had a similar issue where the symbols got optimized out based on the optimization level. If __llvm_profile_raw_version and __llvm_profile_filename always have hidden visibility this should be fine for TAPI.

[zequanwu]

This causing instrprof-darwin-dead-strip.c failed on mac.

FAIL: Profile-x86_64 :: instrprof-darwin-dead-strip.c (1 of 238)
******************** TEST 'Profile-x86_64 :: instrprof-darwin-dead-strip.c' FAILED ********************
Script:
--
: 'RUN: at line 4';      /Users/zequanwu/llvm-project/build/cmake/./bin/clang   -arch x86_64 -stdlib=libc++ -mmacosx-version-min=10.10 -isysroot /Users/zequanwu/llvm-project/build/cmake/../../sysroot/MacOSX.sdk   -fprofile-instr-generate=/Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.profraw -fcoverage-mapping -mllvm -enable-name-compression=false -DCODE=1 -Wl,-dead_strip -o /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c
: 'RUN: at line 5';    /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp
: 'RUN: at line 6';   llvm-profdata merge -o /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.profdata /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.profraw
: 'RUN: at line 7';   llvm-profdata show --all-functions /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.profdata | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=PROF
: 'RUN: at line 8';   llvm-cov show /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp -instr-profile /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.profdata | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=COV
: 'RUN: at line 9';   nm /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=NM
: 'RUN: at line 10';   otool -V -s __DATA __llvm_prf_names /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=PRF_NAMES
: 'RUN: at line 11';   otool -V -s __DATA __llvm_prf_cnts /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=PRF_CNTS
: 'RUN: at line 13';      /Users/zequanwu/llvm-project/build/cmake/./bin/clang  -Wl,-lto_library,/Users/zequanwu/llvm-project/build/cmake/./lib/libLTO.dylib -flto  -arch x86_64 -stdlib=libc++ -mmacosx-version-min=10.10 -isysroot /Users/zequanwu/llvm-project/build/cmake/../../sysroot/MacOSX.sdk   -fprofile-instr-generate=/Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto.profraw -fcoverage-mapping -mllvm -enable-name-compression=false -DCODE=1 -Wl,-dead_strip -flto -o /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c
: 'RUN: at line 14';    /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto
: 'RUN: at line 15';   llvm-profdata merge -o /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto.profdata /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto.profraw
: 'RUN: at line 16';   llvm-profdata show --all-functions /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto.profdata | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=PROF
: 'RUN: at line 17';   llvm-cov show /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto -instr-profile /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto.profdata | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=COV
: 'RUN: at line 18';   nm /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=NM
: 'RUN: at line 19';   otool -V -s __DATA __llvm_prf_names /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=PRF_NAMES
: 'RUN: at line 20';   otool -V -s __DATA __llvm_prf_cnts /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.lto | FileCheck /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c -check-prefix=PRF_CNTS
: 'RUN: at line 28';      /Users/zequanwu/llvm-project/build/cmake/./bin/clang   -arch x86_64 -stdlib=libc++ -mmacosx-version-min=10.10 -isysroot /Users/zequanwu/llvm-project/build/cmake/../../sysroot/MacOSX.sdk   -fprofile-instr-generate -fcoverage-mapping -Wl,-dead_strip -dynamiclib -o /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.nocode.dylib /Users/zequanwu/llvm-project/compiler-rt/test/profile/instrprof-darwin-dead-strip.c
: 'RUN: at line 29';   nm -jgU /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.nocode.dylib > /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.nocode.syms
: 'RUN: at line 30';   nm -jgU /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp | grep -vE "main|foo|mh_execute_header" > /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.code.syms
: 'RUN: at line 31';   diff /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.nocode.syms /Users/zequanwu/llvm-project/build/cmake/projects/compiler-rt/test/profile/Profile-x86_64/Output/instrprof-darwin-dead-strip.c.tmp.code.syms
--
Exit Code: 1

Command Output (stdout):
--
1d0
< ___llvm_profile_filename

--

[abrachet]

The error @zequanwu ran into happens only on MacOS because it this Darwin-only test happens to be the only one that tests instrprof with no code. __llvm_profile_filename doesn't get emitted in this case so it ends up pulling in the one in libprofile.a which is not hidden. I've changed this to make __llvm_profile_filename hidden, as well as __llvm_profile_raw_version even though that symbol is always emitted.

@cishida, to verify, the comment in InstrProfilingVersionVar.c said that __llvm_profile_raw_version was not hidden on Apple platforms because of TAPI, it should be ok to mark this as hidden in libprofile.a, right? I'm guessing this should be no different than when the symbol is emitted by llvm.

[thakis]

This is still breaking Profile-x86_64 :: instrprof-darwin-dead-strip.c on mac. I'm reverting this again for now.

[abrachet]

Use sed to filter nm output instead of grep. grep exits with exit code 1 because there are no matching lines. This is expected because there are no more external symbols other than _main and __mh_execute_header, note _foo has been dead stripped.

[abrachet]

In D135340#3882280, @thakis wrote:

This is still breaking Profile-x86_64 :: instrprof-darwin-dead-strip.c on mac. I'm reverting this again for now.

Sorry about that, I've tested it locally and it should be good to go now. But I'll give some time before resubmitting if you'd like to look it over.

clang/lib/Driver/ToolChains/Darwin.cpp

void Darwin::addProfileRTLibs(const ArgList &Args,
   AddLinkRuntimeLib(Args, CmdArgs, "profile",
                     RuntimeLinkOptions(RLO_AlwaysLink));
 
   bool ForGCOV = needsGCovInstrumentation(Args);
 
   // If we have a symbol export directive and we're linking in the profile
   // runtime, automatically export symbols necessary to implement some of the
   // runtime's functionality.
-  if (hasExportSymbolDirective(Args)) {
-    if (ForGCOV) {
-      addExportedSymbol(CmdArgs, "___gcov_dump");
-      addExportedSymbol(CmdArgs, "___gcov_reset");
-      addExportedSymbol(CmdArgs, "_writeout_fn_list");
-      addExportedSymbol(CmdArgs, "_reset_fn_list");
-    } else {
-      addExportedSymbol(CmdArgs, "___llvm_profile_filename");
-      addExportedSymbol(CmdArgs, "___llvm_profile_raw_version");
-    }
+  if (hasExportSymbolDirective(Args) && ForGCOV) {
   }
 
   // Align __llvm_prf_{cnts,data} sections to the maximum expected page
   // alignment. This allows profile counters to be mmap()'d to disk. Note that
   // it's not enough to just page-align __llvm_prf_cnts: the following section
   // must also be page-aligned so that its data is not clobbered by mmap().
   //
   // The section alignment is only needed when continuous profile sync is

clang/test/Driver/darwin-ld.c

 // LINK_VERSION_DIGITS: invalid version number in '-mlinker-version=133.3.0.1a'
 
 // RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=PROFILE_SECTALIGN %s < %t.log
 // RUN: %clang -target arm64-apple-ios12 -fprofile-instr-generate -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=PROFILE_SECTALIGN %s < %t.log
 // PROFILE_SECTALIGN: "-sectalign" "__DATA" "__llvm_prf_cnts" "0x4000" "-sectalign" "__DATA" "__llvm_prf_data" "0x4000"
 
-// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -exported_symbols_list /dev/null -### %t.o 2> %t.log
-// RUN: FileCheck -check-prefix=PROFILE_EXPORT %s < %t.log
-// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -Wl,-exported_symbols_list,/dev/null -### %t.o 2> %t.log
-// RUN: FileCheck -check-prefix=PROFILE_EXPORT %s < %t.log
-// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -Wl,-exported_symbol,foo -### %t.o 2> %t.log
-// RUN: FileCheck -check-prefix=PROFILE_EXPORT %s < %t.log
-// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -Xlinker -exported_symbol -Xlinker foo -### %t.o 2> %t.log
-// RUN: FileCheck -check-prefix=PROFILE_EXPORT %s < %t.log
-// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -Xlinker -exported_symbols_list -Xlinker /dev/null -### %t.o 2> %t.log
-// RUN: FileCheck -check-prefix=PROFILE_EXPORT %s < %t.log
-// PROFILE_EXPORT: "-exported_symbol" "___llvm_profile_filename" "-exported_symbol" "___llvm_profile_raw_version"
-//
 // RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate --coverage -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=NO_PROFILE_EXPORT %s < %t.log
 // NO_PROFILE_EXPORT-NOT: "-exported_symbol"
 //
 // RUN: %clang -target x86_64-apple-darwin12 --coverage -exported_symbols_list /dev/null -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log
 // RUN: %clang -target x86_64-apple-darwin12 -fprofile-arcs -Wl,-exported_symbols_list,/dev/null -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log

compiler-rt/lib/profile/InstrProfilingNameVar.c

 /*===- InstrProfilingNameVar.c - profile name variable setup  -------------===*\
 |*
 |* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 |* See https://llvm.org/LICENSE.txt for license information.
 |* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 |*
 \*===----------------------------------------------------------------------===*/
 
 #include "InstrProfiling.h"
 
 /* char __llvm_profile_filename[1]
  *
  * The runtime should only provide its own definition of this symbol when the
  * user has not specified one. Set this up by moving the runtime's copy of this
  * symbol to an object file within the archive.
  */
-COMPILER_RT_WEAK char INSTR_PROF_PROFILE_NAME_VAR[1] = {0};
+COMPILER_RT_WEAK COMPILER_RT_VISIBILITY char INSTR_PROF_PROFILE_NAME_VAR[1] = {0};

compiler-rt/lib/profile/InstrProfilingVersionVar.c

 /*===- InstrProfilingVersionVar.c - profile version variable setup  -------===*\
 |*
 |* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 |* See https://llvm.org/LICENSE.txt for license information.
 |* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 |*
 \*===----------------------------------------------------------------------===*/
 
 #include "InstrProfiling.h"
 
 /* uint64 __llvm_profile_raw_version
  *
  * The runtime should only provide its own definition of this symbol when the
  * user has not specified one. Set this up by moving the runtime's copy of this
  * symbol to an object file within the archive.
- *
- * Hide this symbol everywhere except Apple platforms, where its presence is
- * checked by the TAPI tool.
  */
-#if !defined(__APPLE__)
-#define VERSION_VAR_VISIBILITY COMPILER_RT_VISIBILITY
-#else
-#define VERSION_VAR_VISIBILITY
-#endif
-VERSION_VAR_VISIBILITY COMPILER_RT_WEAK uint64_t INSTR_PROF_RAW_VERSION_VAR =
+COMPILER_RT_VISIBILITY COMPILER_RT_WEAK uint64_t INSTR_PROF_RAW_VERSION_VAR =
     INSTR_PROF_RAW_VERSION;

compiler-rt/test/profile/instrprof-darwin-dead-strip.c

 // Note: We expect foo() and some of the profiling data associated with it to
 // be dead-stripped.
 
 // Note: When there is no code in a program, we expect to see the exact same
 // set of external functions provided by the profile runtime.
 
 // RUN: %clang_profgen -fcoverage-mapping -Wl,-dead_strip -dynamiclib -o %t.nocode.dylib %s
 // RUN: nm -jgU %t.nocode.dylib > %t.nocode.syms
-// RUN: nm -jgU %t | grep -vE "main|foo|mh_execute_header" > %t.code.syms
+// RUN: nm -jgU %t | sed -e '/_\{1,\}main/d' -e '/_\{1,\}mh_execute_header/d' > %t.code.syms
 // RUN: diff %t.nocode.syms %t.code.syms
 
 #ifdef CODE
 
 // COV: [[@LINE+1]]{{ *}}|{{ *}}0|void foo()
 void foo() {}
 
 // COV: [[@LINE+1]]{{ *}}|{{ *}}1|int main

llvm/lib/ProfileData/InstrProf.cpp

 void createProfileFileNameVar(Module &M, StringRef InstrProfileOutput) {
   if (InstrProfileOutput.empty())
     return;
   Constant *ProfileNameConst =
       ConstantDataArray::getString(M.getContext(), InstrProfileOutput, true);
   GlobalVariable *ProfileNameVar = new GlobalVariable(
       M, ProfileNameConst->getType(), true, GlobalValue::WeakAnyLinkage,
       ProfileNameConst, INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR));
+  ProfileNameVar->setVisibility(GlobalValue::HiddenVisibility);
   Triple TT(M.getTargetTriple());
   if (TT.supportsCOMDAT()) {
     ProfileNameVar->setLinkage(GlobalValue::ExternalLinkage);
     ProfileNameVar->setComdat(M.getOrInsertComdat(
         StringRef(INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR))));
   }
 }
 

llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp

static GlobalVariable *createIRLevelProfileFlagVar(Module &M, bool IsCS) {
   if (DebugInfoCorrelate)
     ProfileVersion |= VARIANT_MASK_DBG_CORRELATE;
   if (PGOFunctionEntryCoverage)
     ProfileVersion |=
         VARIANT_MASK_BYTE_COVERAGE | VARIANT_MASK_FUNCTION_ENTRY_ONLY;
   auto IRLevelVersionVariable = new GlobalVariable(
       M, IntTy64, true, GlobalValue::WeakAnyLinkage,
       Constant::getIntegerValue(IntTy64, APInt(64, ProfileVersion)), VarName);
-  IRLevelVersionVariable->setVisibility(GlobalValue::DefaultVisibility);
+  IRLevelVersionVariable->setVisibility(GlobalValue::HiddenVisibility);
   Triple TT(M.getTargetTriple());
   if (TT.supportsCOMDAT()) {
     IRLevelVersionVariable->setLinkage(GlobalValue::ExternalLinkage);
     IRLevelVersionVariable->setComdat(M.getOrInsertComdat(VarName));
   }
   return IRLevelVersionVariable;
 }
 

llvm/test/Transforms/PGOProfile/branch1.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -S | FileCheck %s --check-prefix=GEN --check-prefix=GEN-COMDAT
 ; RUN: opt < %s -mtriple=x86_64-apple-darwin -passes=pgo-instr-gen -S | FileCheck %s --check-prefix=GEN --check-prefix=GEN-DARWIN-LINKONCE
 
 ; RUN: llvm-profdata merge %S/Inputs/branch1.proftext -o %t.profdata
 ; RUN: llvm-profdata merge %S/Inputs/branch1_large_count.proftext -o %t.l.profdata
 
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.l.profdata -S | FileCheck %s --check-prefix=USE-LARGE
 
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -pass-remarks=pgo-instrumentation -pgo-emit-branch-prob -S 2>&1| FileCheck %s --check-prefix=ANALYSIS
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 ; GEN-DARWIN-LINKONCE: target triple = "x86_64-apple-darwin"
 
 ; GEN-COMDAT: $__llvm_profile_raw_version = comdat any
-; GEN-COMDAT: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN-COMDAT: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN-LINKONCE: @__llvm_profile_raw_version = linkonce constant i64 {{[0-9]+}}
 ; GEN: @__profn_test_br_1 = private constant [9 x i8] c"test_br_1"
 
 define i32 @test_br_1(i32 %i) {
 ; USE-LABEL: @test_br_1
 ; USE-SAME: !prof ![[FUNC_ENTRY_COUNT:[0-9]+]]
 entry:
 ; GEN: entry:

llvm/test/Transforms/PGOProfile/branch2.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=false -S | FileCheck %s --check-prefixes=GEN,NOTENTRY
 ; RUN: llvm-profdata merge %S/Inputs/branch2.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 
 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=true  -S | FileCheck %s --check-prefixes=GEN,ENTRY
 ; RUN: llvm-profdata merge %S/Inputs/branch2_entry.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use  -pgo-instrument-entry=true -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_test_br_2 = private constant [9 x i8] c"test_br_2"
 
 define i32 @test_br_2(i32 %i) {
 entry:
 ; GEN: entry:
 ; NOTENTRY-NOT: llvm.instrprof.increment
 ; ENTRY: call void @llvm.instrprof.increment(ptr @__profn_test_br_2, i64 {{[0-9]+}}, i32 2, i32 0)
   %cmp = icmp sgt i32 %i, 0

llvm/test/Transforms/PGOProfile/comdat_internal.ll

 ; RUN: opt < %s -passes=pgo-instr-gen,instrprof -S | FileCheck %s
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 $foo = comdat any
 ; CHECK: $foo = comdat any
 
 ; CHECK: $__llvm_profile_raw_version = comdat any
 ; CHECK: $__profc__stdin__foo.[[#FOO_HASH:]] = comdat any
 
 @bar = global ptr @foo, align 8
 
-; CHECK: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; CHECK: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; CHECK-NOT: __profn__stdin__foo
 ; CHECK: @__profc__stdin__foo.[[#FOO_HASH]] = private global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat, align 8
 ; CHECK: @__profd__stdin__foo.[[#FOO_HASH]] = private global { i64, i64, i64, ptr, ptr, i32, [2 x i16] } { i64 -5640069336071256030, i64 [[#FOO_HASH]], i64 sub (i64 ptrtoint (ptr @__profc__stdin__foo.742261418966908927 to i64), i64 ptrtoint (ptr @__profd__stdin__foo.742261418966908927 to i64)), ptr null
 ; CHECK-NOT: @foo
 ; CHECK-SAME: , ptr null, i32 1, [2 x i16] zeroinitializer }, section "__llvm_prf_data", comdat($__profc__stdin__foo.[[#FOO_HASH]]), align 8
 ; CHECK: @__llvm_prf_nm
 ; CHECK: @llvm.compiler.used
 
 define internal i32 @foo() comdat {
 entry:
   ret i32 1
 }

llvm/test/Transforms/PGOProfile/criticaledge.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=false -S | FileCheck %s --check-prefix=GEN
 ; RUN: llvm-profdata merge %S/Inputs/criticaledge.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 ;
 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=true -S | FileCheck %s --check-prefix=GEN
 ; RUN: llvm-profdata merge %S/Inputs/criticaledge_entry.proftext -o %t2.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=true -pgo-test-profile-file=%t2.profdata -S | FileCheck %s --check-prefix=USE
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_test_criticalEdge = private constant [17 x i8] c"test_criticalEdge"
 ; GEN: @__profn__stdin__bar = private constant [11 x i8] c"<stdin>:bar"
 
 define i32 @test_criticalEdge(i32 %i, i32 %j) {
 entry:
 ; CHECK: entry:
 ; NOTENTRY-NOT: call void @llvm.instrprof.increment
 ; ENTRY:   call void @llvm.instrprof.increment(ptr @__profn_test_criticalEdge, i64 {{[0-9]+}}, i32 8, i32 0)

llvm/test/Transforms/PGOProfile/filename.ll

+; RUN: opt < %s -passes='thinlto-pre-link<O2>' --cs-profilegen-file=file -cspgo-kind=cspgo-instr-gen-pipeline -S | FileCheck %s
+
+; CHECK: $__llvm_profile_filename = comdat any
+; CHECK: @__llvm_profile_filename = hidden local_unnamed_addr constant [5 x i8] c"file\00", comdat
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @test() {
+  ret i32 0
+}

llvm/test/Transforms/PGOProfile/instr_entry_bb.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry -S | FileCheck %s --check-prefix=GEN
 ; RUN: opt < %s -passes=pgo-instr-gen,instrprof -pgo-instrument-entry -atomic-first-counter -S | FileCheck %s --check-prefix=GENA
 
 ; RUN: llvm-profdata merge %S/Inputs/branch2.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -pgo-instrument-entry -S | FileCheck %s --check-prefix=USE
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_test_br_2 = private constant [9 x i8] c"test_br_2"
 
 define i32 @test_br_2(i32 %i) {
 entry:
 ; GEN: entry:
 ; GEN: call void @llvm.instrprof.increment(ptr @__profn_test_br_2, i64 {{[0-9]+}}, i32 2, i32 0)
 ; GENA: entry:
 ; GENA: %{{[0-9+]}} = atomicrmw add ptr @__profc_test_br_2, i64 1 monotonic

llvm/test/Transforms/PGOProfile/landingpad.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=false -S | FileCheck %s --check-prefixes=GEN,NOTENTRY
 ; RUN: llvm-profdata merge %S/Inputs/landingpad.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 ;
 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=true -S | FileCheck %s --check-prefixes=GEN,ENTRY
 ; RUN: llvm-profdata merge %S/Inputs/landingpad_entry.proftext -o %t2.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=true -pgo-test-profile-file=%t2.profdata -S | FileCheck %s --check-prefix=USE
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @val = global i32 0, align 4
 @_ZTIi = external constant ptr
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_bar = private constant [3 x i8] c"bar"
 ; GEN: @__profn_foo = private constant [3 x i8] c"foo"
 
 define i32 @bar(i32 %i) {
 entry:
 ; GEN: entry:
 ; GEN: call void @llvm.instrprof.increment(ptr @__profn_bar, i64 {{[0-9]+}}, i32 2, i32 0)
   %rem = srem i32 %i, 3

llvm/test/Transforms/PGOProfile/loop1.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=false -S | FileCheck %s --check-prefixes=GEN,NOTENTRY
 ; RUN: llvm-profdata merge %S/Inputs/loop1.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=true -S | FileCheck %s --check-prefixes=GEN,ENTRY
 ; RUN: llvm-profdata merge %S/Inputs/loop1_entry.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=true -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_test_simple_for = private constant [15 x i8] c"test_simple_for"
 
 define i32 @test_simple_for(i32 %n) {
 entry:
 ; GEN: entry:
 ; NOTENTRY: call void @llvm.instrprof.increment(ptr @__profn_test_simple_for, i64 {{[0-9]+}}, i32 2, i32 1)
 ; ENTRY: call void @llvm.instrprof.increment(ptr @__profn_test_simple_for, i64 {{[0-9]+}}, i32 2, i32 0)
   br label %for.cond

llvm/test/Transforms/PGOProfile/loop2.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=false -S | FileCheck %s --check-prefixes=GEN,NOTENTRY
 ; RUN: llvm-profdata merge %S/Inputs/loop2.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=true -S | FileCheck %s --check-prefixes=GEN,ENTRY
 ; RUN: llvm-profdata merge %S/Inputs/loop2_entry.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=true -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_test_nested_for = private constant [15 x i8] c"test_nested_for"
 
 define i32 @test_nested_for(i32 %r, i32 %s) {
 entry:
 ; GEN: entry:
 ; NOTENTRY: call void @llvm.instrprof.increment(ptr @__profn_test_nested_for, i64 {{[0-9]+}}, i32 3, i32 2)
 ; ENTRY: call void @llvm.instrprof.increment(ptr @__profn_test_nested_for, i64 {{[0-9]+}}, i32 3, i32 0)
   br label %for.cond.outer

llvm/test/Transforms/PGOProfile/lto_cspgo_gen.ll

 ; REQUIRES: x86-registered-target
 
 ; RUN: opt -passes='thinlto-pre-link<O2>' --cs-profilegen-file=alloc -cspgo-kind=cspgo-instr-gen-pipeline -module-summary %s -o %t.bc
 ; RUN: llvm-dis %t.bc -o - | FileCheck %s --check-prefix=IRPGOPRE
 
 ;; Symbol __llvm_profile_filename and __llvm_profile_raw_version are non-prevailing here.
 ; RUN: llvm-lto2 run -lto-cspgo-profile-file=alloc -lto-cspgo-gen -save-temps -o %t %t.bc \
 ; RUN:   -r=%t.bc,f,px \
 ; RUN:   -r=%t.bc,__llvm_profile_filename,x \
 ; RUN:   -r=%t.bc,__llvm_profile_raw_version,x
 ; RUN: llvm-dis %t.0.0.preopt.bc -o - | FileCheck %s --check-prefix=IRPGOBE
 
 ;; Before LTO, we should have the __llvm_profile_raw_version definition.
-; IRPGOPRE: @__llvm_profile_raw_version = constant i64
+; IRPGOPRE: @__llvm_profile_raw_version = hidden constant i64
 
 ;; Non-prevailing __llvm_profile_raw_version is discarded by LTO. Ensure the
 ;; declaration is retained.
-; IRPGOBE: @__llvm_profile_raw_version = external constant i64
+; IRPGOBE: @__llvm_profile_raw_version = external hidden constant i64
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 $f = comdat any
 
 ; Function Attrs: nofree norecurse nosync nounwind readnone uwtable willreturn mustprogress
 define i32 @f() {
 entry:
   ret i32 1
 }
 
 !llvm.module.flags = !{!0}
 !0 = !{i32 1, !"ThinLTO", i32 0}

llvm/test/Transforms/PGOProfile/single_bb.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -S | FileCheck %s --check-prefix=GEN
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_single_bb = private constant [9 x i8] c"single_bb"
 
 define i32 @single_bb() {
 entry:
 ; GEN: entry:
 ; GEN: call void @llvm.instrprof.increment(ptr @__profn_single_bb, i64 {{[0-9]+}}, i32 1, i32 0)
   ret i32 0
 }

llvm/test/Transforms/PGOProfile/switch.ll

 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=false -S | FileCheck %s --check-prefixes=GEN,NOTENTRY
 ; RUN: llvm-profdata merge %S/Inputs/switch.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=false -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 ; RUN: opt < %s -passes=pgo-instr-gen -pgo-instrument-entry=true -S | FileCheck %s --check-prefixes=GEN,ENTRY
 ; RUN: llvm-profdata merge %S/Inputs/switch_entry.proftext -o %t.profdata
 ; RUN: opt < %s -passes=pgo-instr-use -pgo-instrument-entry=true -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 ; GEN: $__llvm_profile_raw_version = comdat any
-; GEN: @__llvm_profile_raw_version = constant i64 {{[0-9]+}}, comdat
+; GEN: @__llvm_profile_raw_version = hidden constant i64 {{[0-9]+}}, comdat
 ; GEN: @__profn_test_switch = private constant [11 x i8] c"test_switch"
 
 define void @test_switch(i32 %i) {
 entry:
 ; GEN: entry:
 ; NOTENTRY-NOT: call void @llvm.instrprof.increment
 ; ENTRY: call void @llvm.instrprof.increment(ptr @__profn_test_switch, i64 {{[0-9]+}}, i32 4, i32 0)
   switch i32 %i, label %sw.default [

llvm/test/Transforms/PGOProfile/thinlto_cspgo_gen.ll

 ; RUN:   -r=%t2.bc,odd,pl \
 ; RUN:   -r=%t2.bc,even,pl \
 ; RUN:   -r=%t2.bc,__llvm_profile_filename,x \
 ; RUN:   -r=%t2.bc,__llvm_profile_raw_version,x
 ; RUN: llvm-dis %t.1.4.opt.bc -o - | FileCheck %s --check-prefixes=CSGEN,PREVAILING
 ; RUN: llvm-dis %t.2.4.opt.bc -o - | FileCheck %s --check-prefixes=CSGEN,NOPREVAILING
 
 ;; Prevailing __llvm_profile_raw_version is kept by LTO.
-; PREVAILING: @__llvm_profile_raw_version = constant i64
+; PREVAILING: @__llvm_profile_raw_version = hidden constant i64
 
 ;; Non-prevailing __llvm_profile_raw_version is discarded by LTO. Ensure the
 ;; declaration is retained.
-; NOPREVAILING: @__llvm_profile_raw_version = external constant i64
+; NOPREVAILING: @__llvm_profile_raw_version = external hidden constant i64
 ; CSGEN: @__profc_
 ; CSGEN: @__profd_
 
 source_filename = "cspgo.c"
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 define dso_local void @foo() #0 !prof !29 {