[CSSPGO] Support stale profile matching for LTO

[wlei]

Summary

As in per-link time, callsites could be optimized out by inlining, we don't have those original call targets in the IR in LTO time. Additionally, the inlined code doesn't actually belong to the original function, the IR locations or pseudo probe parsed from it are incorrect and could mislead the matching later.

This change adds the support to extract the original IR location info from the inlined code, specifically, it make sure to skip all the inlined code that doesn't belong the original function, but before that, it processes the inline frames of the debug info to extract the base frame and recover its callsite and callee target(name).

Measured on some stale profile instances, all showed some perf improvements.

[hoy]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2139–2142

nit: use PrevDIL->getSubprogramLinkageName() instead.

2146

Is the continue needed since instructions in the same BB may not from a single callsite.

[wlei]

addressing feedback

llvm/lib/Transforms/IPO/SampleProfile.cpp

2139–2142

Done, thanks!

2146

We need the continue, this is needed for all the inlined code, because it's not part of the original function.
otherwise the below code will extract the probe and callsite from a different function.

Note that this is under this condition, so it won't affect the original code.

if (DIL->getInlinedAt()) { 
   ....
   continue;
  }

[hoy]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2123

Might be good to mention IR flattening in the comment somewhere which is needed as the flattened profile is always used for matching.

2130

Do we also want to flatten for callsite probes?

[hoy]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2130

Also should this be done under FlattenProfileForMatching?

[wlei]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2130

Do we also want to flatten for callsite probes?

Block probe should be sufficient. for every callsite, there should be a block probe in the same BB, so their debug info inline stack is the same.

Also should this be done under FlattenProfileForMatching?

Not sure if this will works with FlattenProfileForMatching off. Maybe we even don't need this `FlattenProfileForMatching switch, I'm thinking FlattenIR or FlattenProfile should be always beneficial to the matching. Or maybe we need another switch FlattenIRForMatching

[wlei]

update the commment.

[hoy]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2130

Block probe should be sufficient. for every callsite, there should be a block probe in the same BB, so their debug info inline stack is the same.

Sounds good, as long as the inlinee has one block probe left, the original callsite should be recoverd.

Not sure if this will works with FlattenProfileForMatching off. Maybe we even don't need this `FlattenProfileForMatching switch, I'm thinking FlattenIR or FlattenProfile should be always beneficial to the matching. Or maybe we need another switch FlattenIRForMatching

I mean as long as the IR flattening and profile flattening are synchronized it should be fine. Maybe we should just retire the FlattenProfileForMatching switch as we always use flattened profile.

[wlei]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2130

Sounds good to retire FlattenProfileForMatching , I will do it in https://reviews.llvm.org/D156725, which already made some changes to FlattenProfileForMatching.

[wenlei]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2117

nit on function naming: it not only populates IRLocations, but also MatchedCallsiteLocs.

2134

Given we tested isa<PseudoProbeInst>(&I) above, is extractProbe ever going to fail? Remove the if check or replace it with an assertion?

2135

nit: "base inline" is not a canonical term and can be confusing. You mean top-level inliner frame?

2152

nit: instead of spraying TODOs for line-number-based AutoFDO, we can have a top-level top for AutoFDO, and also explain 1) the current behavior for AutoFDO, 2) what actually needs to be done for AutoFDO.

2153–2156

For readability, would it make sense to tweak the code a bit so it's explicit that we're handling not-inlined probes. Initially I got confused since it didn't pay attention to the continue above..

if (isa<PseudoProbeInst>(&I)) {
  get DIL to check for inlining..
  if (Inlined case)... 

  else { // not inlined case

  }
}

2158

I know this is old code, but what intrinsics are we skipping here, is that just for skipping probe intrinsics or something else? If it's for skipping probes, maybe we can consider this?

if (probe inst) {
  record empty string in IRLocations
else if (call inst) {
  record actual call site in IRLocations
}

or

if (probe inst) {
  record empty string in IRLocations
else if (not call inst) {
  continue
}
record actual call site in IRLocations

2376

As I read the code I noticed that "non-direct-call site" can be confusing as it can mean call site that is not direct call. But we really mean to say is 1) not a call site, 2) indirect call site?

[wenlei]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2117

More like findAnchorLocations?

[wlei]

addressing feedback

llvm/lib/Transforms/IPO/SampleProfile.cpp

2117

Sounds good to move MatchedCallsiteLocs out of populateIRLocations, I also saw you mentioned to break the functions in other patch, I will do the refactoring in a new diff.

Regarding the name findAnchorLocations, we use the term "Anchor" for both IR and Profile, see in the runStaleProfileMatching, we use the ProfileAnchors. So maybe still keep populateIRlocations or findIRLocations? after the refactoring, it should only be related with IR.

2134

Sounds good!

2135

changed to top-level frame.

2152

Thanks for the suggestion, refine the comments.

2153–2156

Sounds good!

2158

IntrinsicInst may not only be used for probe intrinsics. I can't remember clearly, but I vaguely remembered there were a lot of dbg intrinsics that messed up the matching, and the fix was to add this isa<IntrinsicInst>(&I) check.

[wenlei]

llvm/lib/Transforms/IPO/SampleProfile.cpp

2117

Assuming the part that deals with profile will be moved out of this function ,how about let's name it as findIRAnchors?

In runStaleProfileMatching, we find ProfileAnchors and match them with IRAnchors established here.

2376

Can you update the comments to avoid ambiguity of "non-direct-call site"?

[wlei]

rebase on https://reviews.llvm.org/D158817

[wenlei]

lgtm, thanks.

llvm/lib/Transforms/IPO/SampleProfile.cpp

private:
 
   LocToLocMap &getIRToProfileLocationMap(const Function &F) {
     auto Ret = FuncMappings.try_emplace(
         FunctionSamples::getCanonicalFnName(F.getName()), LocToLocMap());
     return Ret.first->second;
   }
   void distributeIRToProfileLocationMap();
   void distributeIRToProfileLocationMap(FunctionSamples &FS);
+  void populateIRLocations(
+      const Function &F, const FunctionSamples &FS,
+      std::unordered_set<LineLocation, LineLocationHash> &MatchedCallsiteLocs,
+      std::map<LineLocation, StringRef> &IRLocations);
   void populateProfileCallsites(
       const FunctionSamples &FS,
       StringMap<std::set<LineLocation>> &CalleeToCallsitesMap);
   void runStaleProfileMatching(
       const std::map<LineLocation, StringRef> &IRLocations,
       StringMap<std::set<LineLocation>> &CalleeToCallsitesMap,
       LocToLocMap &IRToProfileLocationMap);
 };
if (ReportProfileStaleness || PersistProfileStaleness ||
       SalvageStaleProfile) {
     MatchingManager =
         std::make_unique<SampleProfileMatcher>(M, *Reader, ProbeManager.get());
   }
 
   return true;
 }
 
+void SampleProfileMatcher::populateIRLocations(
+    const Function &F, const FunctionSamples &FS,
+    std::unordered_set<LineLocation, LineLocationHash> &MatchedCallsiteLocs,
+    std::map<LineLocation, StringRef> &IRLocations) {
+  for (auto &BB : F) {
+    for (auto &I : BB) {
+      // Process inlined code.
+      if (DILocation *DIL = I.getDebugLoc()) {
+        if (DIL->getInlinedAt()) {
+          // Recover the original callsite and call target by analyzing the
+          // inline frames from the debug info.
+          // TODO: Support line-number based location(AutoFDO).
+          if (FunctionSamples::ProfileIsProbeBased &&
+              isa<PseudoProbeInst>(&I)) {
+            // For pseudo probe mode, extracting inline info from the probe inst
+            // is enough.
+            if (std::optional<PseudoProbe> Probe = extractProbe(I)) {
+              // Find the base inline frame.
+              const DILocation *PrevDIL = DIL;
+              for (; DIL->getInlinedAt(); DIL = DIL->getInlinedAt())
+                PrevDIL = DIL;
+
+              LineLocation Callsite =
+                  FunctionSamples::getCallSiteIdentifier(DIL);
+              StringRef CalleeName = PrevDIL->getSubprogramLinkageName();
+              IRLocations.emplace(Callsite, CalleeName);
+            }
+          }
+          // Skip the inlined code since it doesn't belong to the original
+          // function.
+          continue;
+        }
+      }
+
+      // TODO: Support line-number based location(AutoFDO).
+      if (FunctionSamples::ProfileIsProbeBased && isa<PseudoProbeInst>(&I)) {
+        if (std::optional<PseudoProbe> Probe = extractProbe(I))
+          IRLocations.emplace(LineLocation(Probe->Id, 0), StringRef());
+      }
+
+      if (!isa<CallBase>(&I) || isa<IntrinsicInst>(&I))
+        continue;
+
+      const auto *CB = dyn_cast<CallBase>(&I);
+      if (auto &DLoc = I.getDebugLoc()) {
+        LineLocation IRCallsite = FunctionSamples::getCallSiteIdentifier(DLoc);
+
+        StringRef CalleeName;
+        if (Function *Callee = CB->getCalledFunction())
+          CalleeName = FunctionSamples::getCanonicalFnName(Callee->getName());
+
+        // Force to overwrite the callee name in case any non-call location was
+        // written before.
+        auto R = IRLocations.emplace(IRCallsite, CalleeName);
+        R.first->second = CalleeName;
+        assert((!FunctionSamples::ProfileIsProbeBased || R.second ||
+                R.first->second == CalleeName) &&
+               "Overwrite non-call or different callee name location for "
+               "pseudo probe callsite");
+
+        // Go through all the callsites on the IR and flag the callsite if the
+        // target name is the same as the one in the profile.
+        const auto CTM = FS.findCallTargetMapAt(IRCallsite);
+        const auto CallsiteFS = FS.findFunctionSamplesMapAt(IRCallsite);
+
+        // Indirect call case.
+        if (CalleeName.empty()) {
+          // Since indirect call does not have the CalleeName, check
+          // conservatively if callsite in the profile is a callsite location.
+          // This is to avoid nums of false positive since otherwise all the
+          // indirect call samples will be reported as mismatching.
+          if ((CTM && !CTM->empty()) || (CallsiteFS && !CallsiteFS->empty()))
+            MatchedCallsiteLocs.insert(IRCallsite);
+        } else {
+          // Check if the call target name is matched for direct call case.
+          if ((CTM && CTM->count(CalleeName)) ||
+              (CallsiteFS && CallsiteFS->count(CalleeName)))
+            MatchedCallsiteLocs.insert(IRCallsite);
+        }
+      }
+    }
+  }
+}
+
 void SampleProfileMatcher::countProfileMismatches(
     const FunctionSamples &FS,
     const std::unordered_set<LineLocation, LineLocationHash>
         &MatchedCallsiteLocs,
     uint64_t &FuncMismatchedCallsites, uint64_t &FuncProfiledCallsites) {
 
   auto isInvalidLineOffset = [](uint32_t LineOffset) {
     return LineOffset & 0x8000;
if (FuncDesc && ProbeManager->profileIsHashMismatched(*FuncDesc, FS)) {
       MismatchedFuncHashSamples += Count;
       NumMismatchedFuncHash++;
       IsFuncHashMismatch = true;
     }
   }
 
   std::unordered_set<LineLocation, LineLocationHash> MatchedCallsiteLocs;
   // The value of the map is the name of direct callsite and use empty StringRef
   // for non-direct-call site.
   std::map<LineLocation, StringRef> IRLocations;
-
   // Extract profile matching anchors and profile mismatch metrics in the IR.
-  for (auto &BB : F) {
-    for (auto &I : BB) {
-      // TODO: Support line-number based location(AutoFDO).
-      if (FunctionSamples::ProfileIsProbeBased && isa<PseudoProbeInst>(&I)) {
-        if (std::optional<PseudoProbe> Probe = extractProbe(I))
-          IRLocations.emplace(LineLocation(Probe->Id, 0), StringRef());
-      }
-
-      if (!isa<CallBase>(&I) || isa<IntrinsicInst>(&I))
-        continue;
-
-      const auto *CB = dyn_cast<CallBase>(&I);
-      if (auto &DLoc = I.getDebugLoc()) {
-        LineLocation IRCallsite = FunctionSamples::getCallSiteIdentifier(DLoc);
-
-        StringRef CalleeName;
-        if (Function *Callee = CB->getCalledFunction())
-          CalleeName = FunctionSamples::getCanonicalFnName(Callee->getName());
-
-        // Force to overwrite the callee name in case any non-call location was
-        // written before.
-        auto R = IRLocations.emplace(IRCallsite, CalleeName);
-        R.first->second = CalleeName;
-        assert((!FunctionSamples::ProfileIsProbeBased || R.second ||
-                R.first->second == CalleeName) &&
-               "Overwrite non-call or different callee name location for "
-               "pseudo probe callsite");
-
-        // Go through all the callsites on the IR and flag the callsite if the
-        // target name is the same as the one in the profile.
-        const auto CTM = FS.findCallTargetMapAt(IRCallsite);
-        const auto CallsiteFS = FS.findFunctionSamplesMapAt(IRCallsite);
-
-        // Indirect call case.
-        if (CalleeName.empty()) {
-          // Since indirect call does not have the CalleeName, check
-          // conservatively if callsite in the profile is a callsite location.
-          // This is to avoid nums of false positive since otherwise all the
-          // indirect call samples will be reported as mismatching.
-          if ((CTM && !CTM->empty()) || (CallsiteFS && !CallsiteFS->empty()))
-            MatchedCallsiteLocs.insert(IRCallsite);
-        } else {
-          // Check if the call target name is matched for direct call case.
-          if ((CTM && CTM->count(CalleeName)) ||
-              (CallsiteFS && CallsiteFS->count(CalleeName)))
-            MatchedCallsiteLocs.insert(IRCallsite);
-        }
-      }
-    }
-  }
+  populateIRLocations(F, FS, MatchedCallsiteLocs, IRLocations);
 
   // Detect profile mismatch for profile staleness metrics report.
   if (ReportProfileStaleness || PersistProfileStaleness) {
     uint64_t FuncMismatchedCallsites = 0;
     uint64_t FuncProfiledCallsites = 0;
     countProfileMismatches(FS, MatchedCallsiteLocs, FuncMismatchedCallsites,
                            FuncProfiledCallsites);
     TotalProfiledCallsites += FuncProfiledCallsites;

llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-matching-lto.prof

+main:6822:0
+ 1: 0
+ 2: 614
+ 3: 614
+ 4: 603
+ 5: 0
+ 7: 631 bar:631
+ 9: 636 bar:636
+ 6: foo:1900
+  1: 614
+  2: 554
+  3: 59
+  4: 614
+  6: 59 bar:59
+  !CFGChecksum: 563022570642068
+ 8: foo:1859
+  1: 589
+  2: 526
+  3: 63
+  4: 618
+  6: 63 bar:65
+  !CFGChecksum: 563022570642068
+ !CFGChecksum: 1125988587804525
+bar:2401:2401
+ 1: 2401
+ !CFGChecksum: 4294967295

llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-matching-lto.ll

+; REQUIRES: x86_64-linux
+; REQUIRES: asserts
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/pseudo-probe-stale-profile-matching-lto.prof --salvage-stale-profile -S --debug-only=sample-profile,sample-profile-impl 2>&1 | FileCheck %s
+
+
+; CHECK: Run stale profile matching for main
+
+; CHECK: Location is matched from 1 to 1
+; CHECK: Location is matched from 2 to 2
+; CHECK: Location is matched from 4 to 4
+; CHECK: Location is matched from 6 to 6
+; CHECK: Location is matched from 7 to 7
+; CHECK: Location is matched from 8 to 8
+; CHECK: Location is matched from 10 to 10
+
+; CHECK: Callsite with callee:foo is matched from 12 to 6
+; CHECK: Location is rematched backwards from 7 to 1
+; CHECK: Location is rematched backwards from 8 to 2
+; CHECK: Location is rematched backwards from 10 to 4
+; CHECK: Callsite with callee:bar is matched from 13 to 7
+; CHECK: Callsite with callee:foo is matched from 14 to 8
+; CHECK: Callsite with callee:bar is matched from 15 to 9
+
+
+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"
+
+@x = internal global i32 1, align 4, !dbg !0
+
+; Function Attrs: nounwind uwtable
+define dso_local i32 @main() local_unnamed_addr #0 !dbg !49 !prof !55 {
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 1, i32 0, i64 -1), !dbg !56
+  call void @llvm.dbg.value(metadata i32 0, metadata !53, metadata !DIExpression()), !dbg !57
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 2, i32 0, i64 6148914874488455168), !dbg !58
+  br label %1, !dbg !61
+
+1:                                                ; preds = %17, %0
+  %2 = phi i32 [ 0, %0 ], [ %28, %17 ]
+  call void @llvm.dbg.value(metadata i32 %2, metadata !53, metadata !DIExpression()), !dbg !57
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 4, i32 0, i64 -1), !dbg !63
+  %3 = load volatile i32, ptr @x, align 4, !dbg !65, !tbaa !66
+  call void @llvm.dbg.value(metadata i32 %2, metadata !70, metadata !DIExpression()), !dbg !76
+  call void @llvm.dbg.value(metadata i32 %3, metadata !75, metadata !DIExpression()), !dbg !76
+  call void @llvm.pseudoprobe(i64 6699318081062747564, i64 1, i32 0, i64 -1), !dbg !79
+  %4 = urem i32 %2, 10, !dbg !81
+  %5 = icmp eq i32 %4, 0, !dbg !81
+  %6 = zext i1 %5 to i32, !dbg !82
+  %7 = add nsw i32 %3, %6, !dbg !82
+  %8 = call i32 @bar(i32 noundef %7) #4, !dbg !83, !prof !84
+  call void @llvm.pseudoprobe(i64 6699318081062747564, i64 4, i32 0, i64 -1), !dbg !85
+  %9 = load volatile i32, ptr @x, align 4, !dbg !86, !tbaa !66
+  %10 = add nsw i32 %9, %8, !dbg !86
+  store volatile i32 %10, ptr @x, align 4, !dbg !86, !tbaa !66
+  %11 = load volatile i32, ptr @x, align 4, !dbg !87, !tbaa !66
+  %12 = call i32 @bar(i32 noundef %11) #4, !dbg !88, !prof !90
+  %13 = load volatile i32, ptr @x, align 4, !dbg !91, !tbaa !66
+  %14 = add nsw i32 %13, %12, !dbg !91
+  store volatile i32 %14, ptr @x, align 4, !dbg !91, !tbaa !66
+  %15 = load volatile i32, ptr @x, align 4, !dbg !92, !tbaa !66
+  %16 = icmp slt i32 %15, 0, !dbg !94
+  br i1 %16, label %30, label %17, !dbg !95, !prof !96
+
+17:                                               ; preds = %1
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 6, i32 0, i64 -1), !dbg !97
+  %18 = load volatile i32, ptr @x, align 4, !dbg !98, !tbaa !66
+  call void @llvm.dbg.value(metadata i32 %2, metadata !70, metadata !DIExpression()), !dbg !99
+  call void @llvm.dbg.value(metadata i32 %18, metadata !75, metadata !DIExpression()), !dbg !99
+  call void @llvm.pseudoprobe(i64 6699318081062747564, i64 1, i32 0, i64 -1), !dbg !102
+  %19 = zext i1 %5 to i32, !dbg !103
+  %20 = add nsw i32 %18, %19, !dbg !103
+  %21 = call i32 @bar(i32 noundef %20) #4, !dbg !104, !prof !84
+  call void @llvm.pseudoprobe(i64 6699318081062747564, i64 4, i32 0, i64 -1), !dbg !105
+  %22 = load volatile i32, ptr @x, align 4, !dbg !106, !tbaa !66
+  %23 = add nsw i32 %22, %21, !dbg !106
+  store volatile i32 %23, ptr @x, align 4, !dbg !106, !tbaa !66
+  %24 = load volatile i32, ptr @x, align 4, !dbg !107, !tbaa !66
+  %25 = call i32 @bar(i32 noundef %24) #4, !dbg !108, !prof !90
+  %26 = load volatile i32, ptr @x, align 4, !dbg !110, !tbaa !66
+  %27 = add nsw i32 %26, %25, !dbg !110
+  store volatile i32 %27, ptr @x, align 4, !dbg !110, !tbaa !66
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 7, i32 0, i64 -1), !dbg !111
+  %28 = add nuw nsw i32 %2, 1, !dbg !112
+  call void @llvm.dbg.value(metadata i32 %28, metadata !53, metadata !DIExpression()), !dbg !57
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 2, i32 0, i64 -6148914324732641280), !dbg !58
+  %29 = icmp eq i32 %28, 1000000, !dbg !114
+  br i1 %29, label %30, label %1, !dbg !61, !prof !116, !llvm.loop !117
+
+30:                                               ; preds = %17, %1
+  %31 = phi i32 [ 1, %1 ], [ 0, %17 ]
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 8, i32 0, i64 -1), !dbg !121
+  call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 10, i32 0, i64 -1), !dbg !122
+  ret i32 %31, !dbg !122
+}
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite)
+declare void @llvm.pseudoprobe(i64, i64, i32, i64) #1
+
+; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+; Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none) uwtable
+define available_externally dso_local i32 @bar(i32 noundef %0) local_unnamed_addr #3 !dbg !123 !prof !128 {
+  call void @llvm.dbg.value(metadata i32 %0, metadata !127, metadata !DIExpression()), !dbg !129
+  call void @llvm.pseudoprobe(i64 -2012135647395072713, i64 1, i32 0, i64 -1), !dbg !130
+  %2 = add nsw i32 %0, 1, !dbg !131
+  ret i32 %2, !dbg !132
+}
+
+attributes #0 = { nounwind uwtable "disable-tail-calls"="true" "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" "use-sample-profile" }
+attributes #1 = { nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) }
+attributes #2 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
+attributes #3 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) uwtable "disable-tail-calls"="true" "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" "use-sample-profile" }
+attributes #4 = { nounwind }
+
+!llvm.dbg.cu = !{!2, !7}
+!llvm.module.flags = !{!9, !10, !11, !12, !13, !14, !15, !16, !17}
+!llvm.ident = !{!46, !46}
+!llvm.pseudo_probe_desc = !{!47, !48}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 2, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C11, file: !3, producer: "clang version 18.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, debugInfoForProfiling: true, nameTableKind: None)
+!3 = !DIFile(filename: "file1.c", directory: "/home/", checksumkind: CSK_MD5, checksum: "03dfbda098b1285e8c9837f184747483")
+!4 = !{!0}
+!5 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !6)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = distinct !DICompileUnit(language: DW_LANG_C11, file: !8, producer: "clang version 18.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, debugInfoForProfiling: true, nameTableKind: None)
+!8 = !DIFile(filename: "file2.c", directory: "/home", checksumkind: CSK_MD5, checksum: "bd15f56a5a8604ec94485c3dbf9d0cdd")
+!9 = !{i32 7, !"Dwarf Version", i32 5}
+!10 = !{i32 2, !"Debug Info Version", i32 3}
+!11 = !{i32 1, !"wchar_size", i32 4}
+!12 = !{i32 8, !"PIC Level", i32 2}
+!13 = !{i32 7, !"PIE Level", i32 2}
+!14 = !{i32 7, !"uwtable", i32 2}
+!15 = !{i32 7, !"frame-pointer", i32 2}
+!16 = !{i32 1, !"EnableSplitLTOUnit", i32 0}
+!17 = !{i32 1, !"ProfileSummary", !18}
+!18 = !{!19, !20, !21, !22, !23, !24, !25, !26, !27, !28}
+!19 = !{!"ProfileFormat", !"SampleProfile"}
+!20 = !{!"TotalCount", i64 9258}
+!21 = !{!"MaxCount", i64 2401}
+!22 = !{!"MaxInternalCount", i64 0}
+!23 = !{!"MaxFunctionCount", i64 2401}
+!24 = !{!"NumCounts", i64 18}
+!25 = !{!"NumFunctions", i64 2}
+!26 = !{!"IsPartialProfile", i64 0}
+!27 = !{!"PartialProfileRatio", double 0.000000e+00}
+!28 = !{!"DetailedSummary", !29}
+!29 = !{!30, !31, !32, !33, !34, !35, !36, !37, !38, !39, !40, !41, !42, !43, !44, !45}
+!30 = !{i32 10000, i64 2401, i32 1}
+!31 = !{i32 100000, i64 2401, i32 1}
+!32 = !{i32 200000, i64 2401, i32 1}
+!33 = !{i32 300000, i64 636, i32 2}
+!34 = !{i32 400000, i64 618, i32 4}
+!35 = !{i32 500000, i64 614, i32 8}
+!36 = !{i32 600000, i64 614, i32 8}
+!37 = !{i32 700000, i64 614, i32 8}
+!38 = !{i32 800000, i64 589, i32 10}
+!39 = !{i32 900000, i64 554, i32 11}
+!40 = !{i32 950000, i64 526, i32 12}
+!41 = !{i32 990000, i64 59, i32 16}
+!42 = !{i32 999000, i64 59, i32 16}
+!43 = !{i32 999900, i64 59, i32 16}
+!44 = !{i32 999990, i64 59, i32 16}
+!45 = !{i32 999999, i64 59, i32 16}
+!46 = !{!"clang version 18.0.0"}
+!47 = !{i64 6699318081062747564, i64 563022570642068, !"foo"}
+!48 = !{i64 -2624081020897602054, i64 1126124211449298, !"main"}
+!49 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 11, type: !50, scopeLine: 12, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !52)
+!50 = !DISubroutineType(types: !51)
+!51 = !{!6}
+!52 = !{!53}
+!53 = !DILocalVariable(name: "i", scope: !54, file: !3, line: 13, type: !6)
+!54 = distinct !DILexicalBlock(scope: !49, file: !3, line: 13, column: 3)
+!55 = !{!"function_entry_count", i64 608}
+!56 = !DILocation(line: 13, column: 11, scope: !54)
+!57 = !DILocation(line: 0, scope: !54)
+!58 = !DILocation(line: 13, column: 18, scope: !59)
+!59 = !DILexicalBlockFile(scope: !60, file: !3, discriminator: 0)
+!60 = distinct !DILexicalBlock(scope: !54, file: !3, line: 13, column: 3)
+!61 = !DILocation(line: 13, column: 3, scope: !62)
+!62 = !DILexicalBlockFile(scope: !54, file: !3, discriminator: 2)
+!63 = !DILocation(line: 14, column: 15, scope: !64)
+!64 = distinct !DILexicalBlock(scope: !60, file: !3, line: 13, column: 40)
+!65 = !DILocation(line: 14, column: 18, scope: !64)
+!66 = !{!67, !67, i64 0}
+!67 = !{!"int", !68, i64 0}
+!68 = !{!"omnipotent char", !69, i64 0}
+!69 = !{!"Simple C/C++ TBAA"}
+!70 = !DILocalVariable(name: "i", arg: 1, scope: !71, file: !3, line: 6, type: !6)
+!71 = distinct !DISubprogram(name: "foo", scope: !3, file: !3, line: 6, type: !72, scopeLine: 6, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !74)
+!72 = !DISubroutineType(types: !73)
+!73 = !{!6, !6, !6}
+!74 = !{!70, !75}
+!75 = !DILocalVariable(name: "p", arg: 2, scope: !71, file: !3, line: 6, type: !6)
+!76 = !DILocation(line: 0, scope: !71, inlinedAt: !77)
+!77 = distinct !DILocation(line: 14, column: 11, scope: !78)
+!78 = !DILexicalBlockFile(scope: !64, file: !3, discriminator: 186646631)
+!79 = !DILocation(line: 7, column: 6, scope: !80, inlinedAt: !77)
+!80 = distinct !DILexicalBlock(scope: !71, file: !3, line: 7, column: 6)
+!81 = !DILocation(line: 7, column: 8, scope: !80, inlinedAt: !77)
+!82 = !DILocation(line: 7, column: 6, scope: !71, inlinedAt: !77)
+!83 = !DILocation(line: 0, scope: !80, inlinedAt: !77)
+!84 = !{!"branch_weights", i64 614}
+!85 = !DILocation(line: 9, column: 1, scope: !71, inlinedAt: !77)
+!86 = !DILocation(line: 14, column: 8, scope: !64)
+!87 = !DILocation(line: 15, column: 15, scope: !64)
+!88 = !DILocation(line: 15, column: 11, scope: !89)
+!89 = !DILexicalBlockFile(scope: !64, file: !3, discriminator: 186646639)
+!90 = !{!"branch_weights", i32 614}
+!91 = !DILocation(line: 15, column: 8, scope: !64)
+!92 = !DILocation(line: 16, column: 9, scope: !93)
+!93 = distinct !DILexicalBlock(scope: !64, file: !3, line: 16, column: 9)
+!94 = !DILocation(line: 16, column: 11, scope: !93)
+!95 = !DILocation(line: 16, column: 9, scope: !64)
+!96 = !{!"branch_weights", i32 0, i32 614}
+!97 = !DILocation(line: 18, column: 15, scope: !64)
+!98 = !DILocation(line: 18, column: 18, scope: !64)
+!99 = !DILocation(line: 0, scope: !71, inlinedAt: !100)
+!100 = distinct !DILocation(line: 18, column: 11, scope: !101)
+!101 = !DILexicalBlockFile(scope: !64, file: !3, discriminator: 186646647)
+!102 = !DILocation(line: 7, column: 6, scope: !80, inlinedAt: !100)
+!103 = !DILocation(line: 7, column: 6, scope: !71, inlinedAt: !100)
+!104 = !DILocation(line: 0, scope: !80, inlinedAt: !100)
+!105 = !DILocation(line: 9, column: 1, scope: !71, inlinedAt: !100)
+!106 = !DILocation(line: 18, column: 8, scope: !64)
+!107 = !DILocation(line: 19, column: 15, scope: !64)
+!108 = !DILocation(line: 19, column: 11, scope: !109)
+!109 = !DILexicalBlockFile(scope: !64, file: !3, discriminator: 186646655)
+!110 = !DILocation(line: 19, column: 8, scope: !64)
+!111 = !DILocation(line: 13, column: 36, scope: !59)
+!112 = !DILocation(line: 13, column: 36, scope: !113)
+!113 = !DILexicalBlockFile(scope: !60, file: !3, discriminator: 6)
+!114 = !DILocation(line: 13, column: 20, scope: !115)
+!115 = !DILexicalBlockFile(scope: !60, file: !3, discriminator: 2)
+!116 = !{!"branch_weights", i32 608, i32 614}
+!117 = distinct !{!117, !118, !119, !120}
+!118 = !DILocation(line: 13, column: 3, scope: !54)
+!119 = !DILocation(line: 20, column: 3, scope: !54)
+!120 = !{!"llvm.loop.mustprogress"}
+!121 = !DILocation(line: 0, scope: !49)
+!122 = !DILocation(line: 22, column: 1, scope: !49)
+!123 = distinct !DISubprogram(name: "bar", scope: !8, file: !8, line: 1, type: !124, scopeLine: 1, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !126)
+!124 = !DISubroutineType(types: !125)
+!125 = !{!6, !6}
+!126 = !{!127}
+!127 = !DILocalVariable(name: "x", arg: 1, scope: !123, file: !8, line: 1, type: !6)
+!128 = !{!"function_entry_count", i64 2401}
+!129 = !DILocation(line: 0, scope: !123)
+!130 = !DILocation(line: 5, column: 10, scope: !123)
+!131 = !DILocation(line: 5, column: 12, scope: !123)
+!132 = !DILocation(line: 5, column: 3, scope: !123)