[SampleFDO] Match functions with the same base function name #126688
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@llvm/pr-subscribers-llvm-transforms Author: Lei Wang (wlei-llvm) ChangesSometimes, 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:
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"
+
+@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"}
|
|
@llvm/pr-subscribers-pgo Author: Lei Wang (wlei-llvm) ChangesSometimes, 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:
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"
+
+@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"}
|
WenleiHe
reviewed
Feb 16, 2025
Comment on lines
+746
to
+747
| ? std::string(BaseNamePtr, BaseNameSize) | ||
| : std::string(); |
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Haven't looked closely, but is BaseNamePtr reusing some the buffer from BaseNameBuf? We cannot return anything pointing to local buffer.
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I checked the https://cplusplus.com/reference/string/string/string/, for std::string ctor
(4) from c-string
Copies the null-terminated character sequence (C-string) pointed by s.
the std::string(const char* s, size_t n) ctor doesn't reuse the memory from the input s but creates an internal memory to copy the value. So it doesn't return value from the local buffer(BaseNameBuf)
| ? std::string(BaseNamePtr, BaseNameSize) | ||
| : std::string(); | ||
| }; | ||
| auto IRBaseName = GetBaseName(IRFunc.getName()); |
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Does the base name include parameters? can we differentiate overload functions with the base name only? If not, I wonder if we should treat base name comparison as a fall back only when there is no anchor in functions?
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Good point. It doesn't include the parameters. I was thinking to make the check in the early place so that if it passes, we can skip the later anchor LCS which is a heavy check.
If not, I wonder if we should treat base name comparison as a fall back only when there is no anchor in functions?
I see, but then it doesn't work for the case I mentioned in other comment, where all the anchors are mismatched but the function still match. Seems like a tradeoff
(1) mismatch between overload functions vs (2) mismatch with all parameter changes.
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Ok, I wonder if we should do this in bottom-up manner.
For leaf functions, base-name match is enough to conclude a match (currently we conclude mismatch as we don't have enough number of anchors there), but for non-leaf, it can still depend on match from its child? That should safer?
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I guess if we are not doing the function/profile comparison recursively, what I suggested above won't work.
Are we doing it recursively when we cannot decide if where a callee funciton/profile is a match?
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I guess if we are not doing the function/profile comparison recursively, what I suggested above won't work.
Are we doing it recursively when we cannot decide if where a callee funciton/profile is a match?
Yeah, we don't do it recursively, we only look up for two levels for a matched caller.
|
@kazutakahirata I think this is relevant for memprof anchor matching too. |
I observed some cases: |
david-xl
approved these changes
Mar 10, 2025
basioli-k
added a commit
that referenced
this pull request
Mar 24, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/15074 Here is the relevant piece of the build log for the reference |
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Sometimes, there may be no matched anchors but the functions still match. e.g. if the function’s template typename changes, all the callsites that use the type are mismatched and the caller function that contains those callsite are mismatched. Introduce a check to match the functions if their demangled base names are the same.