[MemProf] Expand optimization scope to internal linkage function (#73236)

Now MemProf can't do IR annotation right in the local linkage function
and global initial function __cxx_global_var_init. In llvm-profdata
which convert raw memory profile to memory profile, it uses function
name in dwarf to create GUID. But when llvm consumes memory profile, it
use `getIRPGOFuncName` or `getPGOFuncName` which returns local linkage
function as `FileName;FunctionName` or `FileName:FunctionName` to get
function name and create GUID. So profile creator's GUID is not same as
profile consumer.
So I think MemProf should be used with `unique-internal-linkage-names`
and don't use PGOFuncName.
__cxx_global_var_init is created later than where
UniqueInternalLinkageNames works. So I add uniq suffix to
__cxx_global_var_init additionally.

Co-authored-by: lifengxiang <[email protected]>

Author: lifengxiang1025

llvm/lib/Transforms/Instrumentation/MemProfiler.cpp

@@ -676,25 +676,17 @@ static void readMemprof(Module &M, Function &F,
                         IndexedInstrProfReader *MemProfReader,
                         const TargetLibraryInfo &TLI) {
   auto &Ctx = M.getContext();
-
-  auto FuncName = getIRPGOFuncName(F);
+  // Previously we used getIRPGOFuncName() here. If F is local linkage,
+  // getIRPGOFuncName() returns FuncName with prefix 'FileName;'. But
+  // llvm-profdata uses FuncName in dwarf to create GUID which doesn't
+  // contain FileName's prefix. It caused local linkage function can't
+  // find MemProfRecord. So we use getName() now.
+  // 'unique-internal-linkage-names' can make MemProf work better for local
+  // linkage function.
+  auto FuncName = F.getName();
   auto FuncGUID = Function::getGUID(FuncName);
   std::optional<memprof::MemProfRecord> MemProfRec;
   auto Err = MemProfReader->getMemProfRecord(FuncGUID).moveInto(MemProfRec);
-  if (Err) {
-    // If we don't find getIRPGOFuncName(), try getPGOFuncName() to handle
-    // profiles built by older compilers
-    Err = handleErrors(std::move(Err), [&](const InstrProfError &IE) -> Error {
-      if (IE.get() != instrprof_error::unknown_function)
-        return make_error<InstrProfError>(IE);
-      auto FuncName = getPGOFuncName(F);
-      auto FuncGUID = Function::getGUID(FuncName);
-      if (auto Err =
-              MemProfReader->getMemProfRecord(FuncGUID).moveInto(MemProfRec))
-        return Err;
-      return Error::success();
-    });
-  }
   if (Err) {
     handleAllErrors(std::move(Err), [&](const InstrProfError &IPE) {
       auto Err = IPE.get();

llvm/test/Transforms/PGOProfile/Inputs/memprof_internal_linkage.exe

@@ -127,3 +127,21 @@ ${CLANG} ${COMMON_FLAGS} -fmemory-profile -DUSE_MUSTTAIL=1 ${OUTDIR}/memprof_mis
 env MEMPROF_OPTIONS=log_path=stdout ${OUTDIR}/memprof_missing_leaf.exe > ${OUTDIR}/memprof_missing_leaf.memprofraw
 
 rm ${OUTDIR}/memprof_missing_leaf.cc
+
+cat > ${OUTDIR}/memprof_internal_linkage.cc << EOF
+#include <cstring>
+#include <unistd.h>
+static void foo() {
+  int *a = new int[5];
+  memset(a, 0, 5);
+}
+int main(int argc, char **argv) {
+  foo();
+  return 0;
+}
+EOF
+
+${CLANG} ${COMMON_FLAGS} -fmemory-profile -funique-internal-linkage-names ${OUTDIR}/memprof_internal_linkage.cc -o ${OUTDIR}/memprof_internal_linkage.exe
+env MEMPROF_OPTIONS=log_path=stdout ${OUTDIR}/memprof_internal_linkage.exe > ${OUTDIR}/memprof_internal_linkage.memprofraw
+
+rm ${OUTDIR}/memprof_internal_linkage.cc

llvm/test/Transforms/PGOProfile/Inputs/memprof_internal_linkage.memprofraw

@@ -0,0 +1,84 @@
+;; Tests memprof when contains internal linkage function.
+
+;; Avoid failures on big-endian systems that can't read the profile properly
+; REQUIRES: x86_64-linux
+
+;; TODO: Use text profile inputs once that is available for memprof.
+;; # To update the Inputs below, run Inputs/update_memprof_inputs.sh.
+;; # To generate below LLVM IR for use in matching.
+;; $ clang++ -gmlt -fdebug-info-for-profiling -S %S/Inputs/memprof_internal_linkage.cc -emit-llvm -funique-internal-linkage-names
+
+; RUN: llvm-profdata merge %S/Inputs/memprof_internal_linkage.memprofraw --profiled-binary %S/Inputs/memprof_internal_linkage.exe -o %t.memprofdata
+; RUN: opt < %s -passes='memprof-use<profile-filename=%t.memprofdata>' -S | FileCheck %s
+
+; CHECK: call {{.*}} @_Znam{{.*}} #[[ATTR:[0-9]+]]
+; CHECK: attributes #[[ATTR]] = { builtin allocsize(0) "memprof"="notcold" }
+
+; ModuleID = 'memprof_internal_linkage.cc'
+source_filename = "memprof_internal_linkage.cc"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: mustprogress noinline norecurse optnone uwtable
+define dso_local noundef i32 @main(i32 noundef %argc, ptr noundef %argv) #0 !dbg !10 {
+entry:
+  %retval = alloca i32, align 4
+  %argc.addr = alloca i32, align 4
+  %argv.addr = alloca ptr, align 8
+  store i32 0, ptr %retval, align 4
+  store i32 %argc, ptr %argc.addr, align 4
+  store ptr %argv, ptr %argv.addr, align 8
+  call void @_ZL3foov.__uniq.231888424933890731874095357293037629092() #4, !dbg !14
+  ret i32 0, !dbg !15
+}
+
+; Function Attrs: mustprogress noinline optnone uwtable
+define internal void @_ZL3foov.__uniq.231888424933890731874095357293037629092() #1 !dbg !16 {
+entry:
+  %a = alloca ptr, align 8
+  %call = call noalias noundef nonnull ptr @_Znam(i64 noundef 20) #5, !dbg !17
+  store ptr %call, ptr %a, align 8, !dbg !18
+  %0 = load ptr, ptr %a, align 8, !dbg !19
+  call void @llvm.memset.p0.i64(ptr align 4 %0, i8 0, i64 5, i1 false), !dbg !20
+  ret void, !dbg !21
+}
+
+; Function Attrs: nobuiltin allocsize(0)
+declare noundef nonnull ptr @_Znam(i64 noundef) #2
+
+; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
+declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #3
+
+attributes #0 = { mustprogress noinline norecurse optnone uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #1 = { mustprogress noinline optnone uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "sample-profile-suffix-elision-policy"="selected" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #2 = { nobuiltin allocsize(0) "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #3 = { nocallback nofree nounwind willreturn memory(argmem: write) }
+attributes #4 = { "sample-profile-suffix-elision-policy"="selected" }
+attributes #5 = { builtin allocsize(0) }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 18.0.0 (https://github.com/llvm/llvm-project.git a604a1112a611ea867dc4e8d164021c7b055e18a)", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, splitDebugInlining: false, debugInfoForProfiling: true, nameTableKind: None)
+!1 = !DIFile(filename: "memprof_internal_linkage.cc", directory: ".", checksumkind: CSK_MD5, checksum: "de848419432086fd9ed6dda04f3bf0ac")
+!2 = !{i32 7, !"Dwarf Version", i32 5}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{i32 8, !"PIC Level", i32 2}
+!6 = !{i32 7, !"PIE Level", i32 2}
+!7 = !{i32 7, !"uwtable", i32 2}
+!8 = !{i32 7, !"frame-pointer", i32 2}
+!9 = !{!"clang version 18.0.0 (https://github.com/llvm/llvm-project.git a604a1112a611ea867dc4e8d164021c7b055e18a)"}
+!10 = distinct !DISubprogram(name: "main", scope: !11, file: !11, line: 7, type: !12, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0)
+!11 = !DIFile(filename: "memprof_internal_linkage.cc", directory: ".", checksumkind: CSK_MD5, checksum: "de848419432086fd9ed6dda04f3bf0ac")
+!12 = !DISubroutineType(types: !13)
+!13 = !{}
+!14 = !DILocation(line: 8, column: 3, scope: !10)
+!15 = !DILocation(line: 9, column: 3, scope: !10)
+!16 = distinct !DISubprogram(name: "foo", linkageName: "_ZL3foov.__uniq.231888424933890731874095357293037629092", scope: !11, file: !11, line: 3, type: !12, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition, unit: !0)
+!17 = !DILocation(line: 4, column: 12, scope: !16)
+!18 = !DILocation(line: 4, column: 8, scope: !16)
+!19 = !DILocation(line: 5, column: 10, scope: !16)
+!20 = !DILocation(line: 5, column: 3, scope: !16)
+!21 = !DILocation(line: 6, column: 1, scope: !16)