[llvm] [SampleFDO] Match functions with the same base function name (PR #126688)
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Thu Feb 13 00:01:00 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Lei Wang (wlei-llvm)
<details>
<summary>Changes</summary>
Sometimes, there may be no anchors for the profile or IR but the functions still match. Introduce a check to match the functions if their demangled base names are the same.
---
Full diff: https://github.com/llvm/llvm-project/pull/126688.diff
4 Files Affected:
- (modified) llvm/lib/Transforms/IPO/CMakeLists.txt (+1)
- (modified) llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp (+28)
- (added) llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof (+12)
- (added) llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll (+133)
``````````diff
diff --git a/llvm/lib/Transforms/IPO/CMakeLists.txt b/llvm/lib/Transforms/IPO/CMakeLists.txt
index 15cb57399d246..a1ebd0cbbbe3c 100644
--- a/llvm/lib/Transforms/IPO/CMakeLists.txt
+++ b/llvm/lib/Transforms/IPO/CMakeLists.txt
@@ -64,6 +64,7 @@ add_llvm_component_library(LLVMipo
FrontendOpenMP
InstCombine
IRReader
+ Demangle
Linker
Object
ProfileData
diff --git a/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp b/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
index 313a50477a314..f203da82785be 100644
--- a/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfileMatcher.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/SampleProfileMatcher.h"
+#include "llvm/Demangle/Demangle.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/Support/CommandLine.h"
@@ -727,6 +728,33 @@ bool SampleProfileMatcher::functionMatchesProfileHelper(
// two sequences are.
float Similarity = 0.0;
+ // Match the functions if they have the same base name(after demangling) and
+ // skip the similarity check.
+ ItaniumPartialDemangler Demangler;
+ // Helper lambda to demangle and get the base name. If the demangling failed,
+ // return an empty string.
+ auto GetBaseName = [&](StringRef FName) {
+ auto FunctionName = FName.str();
+ if (Demangler.partialDemangle(FunctionName.c_str()))
+ return std::string();
+ constexpr size_t MaxBaseNameSize = 4096;
+ char BaseNameBuf[MaxBaseNameSize] = {};
+ size_t BaseNameSize = MaxBaseNameSize;
+ char *BaseNamePtr =
+ Demangler.getFunctionBaseName(BaseNameBuf, &BaseNameSize);
+ return (BaseNamePtr && BaseNameSize)
+ ? std::string(BaseNamePtr, BaseNameSize)
+ : std::string();
+ };
+ auto IRBaseName = GetBaseName(IRFunc.getName());
+ auto ProfBaseName = GetBaseName(ProfFunc.stringRef());
+ if (!IRBaseName.empty() && IRBaseName == ProfBaseName) {
+ LLVM_DEBUG(dbgs() << "The functions " << IRFunc.getName() << "(IR) and "
+ << ProfFunc << "(Profile) share the same base name: "
+ << IRBaseName << ".\n");
+ return true;
+ }
+
const auto *FSForMatching = getFlattenedSamplesFor(ProfFunc);
// With extbinary profile format, initial profile loading only reads profile
// based on current function names in the module.
diff --git a/llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof b/llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof
new file mode 100644
index 0000000000000..e194d4d4aae32
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/Inputs/pseudo-probe-stale-profile-name-similarity.prof
@@ -0,0 +1,12 @@
+main:200:0
+ 1: 0
+ 2: 50
+ 3: 0
+ 4: 50
+ 5: 52 _Z3fooi:52
+ 6: 50
+ 7: 0
+ !CFGChecksum: 281582264815352
+_Z3fooi:52:52
+ 1: 52
+ !CFGChecksum: 4294967295000
diff --git a/llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll b/llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll
new file mode 100644
index 0000000000000..4e435f4586465
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/pseudo-probe-stale-profile-name-similarity.ll
@@ -0,0 +1,133 @@
+; REQUIRES: x86_64-linux
+; REQUIRES: asserts
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/pseudo-probe-stale-profile-name-similarity.prof --salvage-stale-profile --salvage-unused-profile -S --debug-only=sample-profile,sample-profile-matcher,sample-profile-impl 2>&1 | FileCheck %s
+
+; CHECK: Function _Z3fool is not in profile or profile symbol list.
+; CHECK: Run stale profile matching for main
+; CHECK: The functions _Z3fool(IR) and _Z3fooi(Profile) share the same base name: foo
+; CHECK: Function:_Z3fool matches profile:_Z3fooi
+; CHECK: Run stale profile matching for _Z3fool
+
+
+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"
+
+ at x = dso_local global i32 0, align 4, !dbg !0
+
+; Function Attrs: mustprogress noinline nounwind uwtable
+define dso_local void @_Z3fool(i64 noundef %y) #0 !dbg !17 {
+entry:
+ #dbg_value(i64 %y, !22, !DIExpression(), !23)
+ call void @llvm.pseudoprobe(i64 5326982120444056491, i64 1, i32 0, i64 -1), !dbg !24
+ %0 = load volatile i32, ptr @x, align 4, !dbg !25, !tbaa !26
+ %conv = sext i32 %0 to i64, !dbg !25
+ %add = add nsw i64 %conv, %y, !dbg !25
+ %conv1 = trunc i64 %add to i32, !dbg !25
+ store volatile i32 %conv1, ptr @x, align 4, !dbg !25, !tbaa !26
+ ret void, !dbg !30
+}
+
+; Function Attrs: mustprogress norecurse nounwind uwtable
+define dso_local noundef i32 @main() #1 !dbg !31 {
+entry:
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 1, i32 0, i64 -1), !dbg !37
+ #dbg_value(i32 0, !35, !DIExpression(), !38)
+ br label %for.cond, !dbg !39
+
+for.cond: ; preds = %for.body, %entry
+ %i.0 = phi i32 [ 0, %entry ], [ %inc, %for.body ], !dbg !40
+ #dbg_value(i32 %i.0, !35, !DIExpression(), !38)
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 2, i32 0, i64 -1), !dbg !41
+ %cmp = icmp slt i32 %i.0, 1000000, !dbg !43
+ br i1 %cmp, label %for.body, label %for.cond.cleanup, !dbg !44
+
+for.cond.cleanup: ; preds = %for.cond
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 3, i32 0, i64 -1), !dbg !45
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 7, i32 0, i64 -1), !dbg !46
+ ret i32 0, !dbg !46
+
+for.body: ; preds = %for.cond
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 4, i32 0, i64 -1), !dbg !47
+ %conv = sext i32 %i.0 to i64, !dbg !47
+ call void @_Z3fool(i64 noundef %conv), !dbg !49
+ call void @llvm.pseudoprobe(i64 -2624081020897602054, i64 6, i32 0, i64 -1), !dbg !51
+ %inc = add nsw i32 %i.0, 1, !dbg !51
+ #dbg_value(i32 %inc, !35, !DIExpression(), !38)
+ br label %for.cond, !dbg !52, !llvm.loop !53
+}
+
+; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+declare void @llvm.lifetime.start.p0(i64 immarg, ptr captures(none)) #2
+
+; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+declare void @llvm.lifetime.end.p0(i64 immarg, ptr captures(none)) #2
+
+; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite)
+declare void @llvm.pseudoprobe(i64, i64, i32, i64) #3
+
+attributes #0 = { mustprogress noinline nounwind uwtable "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 = { mustprogress norecurse nounwind uwtable "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 #2 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+attributes #3 = { mustprogress nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!7, !8, !9, !10, !11, !12, !13}
+!llvm.ident = !{!14}
+!llvm.pseudo_probe_desc = !{!15, !16}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 21.0.0git (https://github.com/llvm/llvm-project.git c9f1d2cbf18990311ea1287cc154e3784a10a3b0)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "test_rename.c", directory: "/home", checksumkind: CSK_MD5, checksum: "2991f6c78cef4c393285c97c0f5dabc4")
+!4 = !{!0}
+!5 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !6)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = !{i32 7, !"Dwarf Version", i32 5}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{i32 1, !"wchar_size", i32 4}
+!10 = !{i32 8, !"PIC Level", i32 2}
+!11 = !{i32 7, !"PIE Level", i32 2}
+!12 = !{i32 7, !"uwtable", i32 2}
+!13 = !{i32 7, !"debug-info-assignment-tracking", i1 true}
+!14 = !{!"clang version 21.0.0git (https://github.com/llvm/llvm-project.git c9f1d2cbf18990311ea1287cc154e3784a10a3b0)"}
+!15 = !{i64 5326982120444056491, i64 4294967295, !"_Z3fool"}
+!16 = !{i64 -2624081020897602054, i64 281582264815352, !"main"}
+!17 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fool", scope: !3, file: !3, line: 3, type: !18, scopeLine: 3, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !21)
+!18 = !DISubroutineType(types: !19)
+!19 = !{null, !20}
+!20 = !DIBasicType(name: "long", size: 64, encoding: DW_ATE_signed)
+!21 = !{!22}
+!22 = !DILocalVariable(name: "y", arg: 1, scope: !17, file: !3, line: 3, type: !20)
+!23 = !DILocation(line: 0, scope: !17)
+!24 = !DILocation(line: 4, column: 9, scope: !17)
+!25 = !DILocation(line: 4, column: 6, scope: !17)
+!26 = !{!27, !27, i64 0}
+!27 = !{!"int", !28, i64 0}
+!28 = !{!"omnipotent char", !29, i64 0}
+!29 = !{!"Simple C++ TBAA"}
+!30 = !DILocation(line: 5, column: 1, scope: !17)
+!31 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 7, type: !32, scopeLine: 7, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !34)
+!32 = !DISubroutineType(types: !33)
+!33 = !{!6}
+!34 = !{!35}
+!35 = !DILocalVariable(name: "i", scope: !36, file: !3, line: 8, type: !6)
+!36 = distinct !DILexicalBlock(scope: !31, file: !3, line: 8, column: 3)
+!37 = !DILocation(line: 8, column: 12, scope: !36)
+!38 = !DILocation(line: 0, scope: !36)
+!39 = !DILocation(line: 8, column: 8, scope: !36)
+!40 = !DILocation(line: 8, scope: !36)
+!41 = !DILocation(line: 8, column: 19, scope: !42)
+!42 = distinct !DILexicalBlock(scope: !36, file: !3, line: 8, column: 3)
+!43 = !DILocation(line: 8, column: 21, scope: !42)
+!44 = !DILocation(line: 8, column: 3, scope: !36)
+!45 = !DILocation(line: 0, scope: !31)
+!46 = !DILocation(line: 11, column: 1, scope: !31)
+!47 = !DILocation(line: 9, column: 11, scope: !48)
+!48 = distinct !DILexicalBlock(scope: !42, file: !3, line: 8, column: 41)
+!49 = !DILocation(line: 9, column: 7, scope: !50)
+!50 = !DILexicalBlockFile(scope: !48, file: !3, discriminator: 455082031)
+!51 = !DILocation(line: 8, column: 37, scope: !42)
+!52 = !DILocation(line: 8, column: 3, scope: !42)
+!53 = distinct !{!53, !44, !54, !55}
+!54 = !DILocation(line: 10, column: 3, scope: !36)
+!55 = !{!"llvm.loop.mustprogress"}
``````````
</details>
https://github.com/llvm/llvm-project/pull/126688
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