[llvm] [memprof] Undrift MemProfRecord (PR #120138)
Kazu Hirata via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 17 13:11:25 PST 2024
https://github.com/kazutakahirata updated https://github.com/llvm/llvm-project/pull/120138
>From 678c2ae73337bb4bee218da1d00ab4bf26622ef6 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Tue, 19 Nov 2024 13:04:13 -0800
Subject: [PATCH 1/3] [memprof] Undrift MemProfRecord
This patch undrifts source locations in MemProfRecord before readMemprof
starts the matching process.
The thoery of operation is as follows:
1. Collect the lists of direct calls, one from the IR and the other
from the profile.
2. Compute the correspondence (called undrift map in the patch)
between the two lists with longestCommonSequence.
3. Apply the undrift map just before readMemprof consumes
MemProfRecord.
The new function gated by a flag that is off by default.
The test case is identical to recently added
memprof_annotate_yaml.test except that the source location in the
profile has been modified.
---
.../Instrumentation/MemProfiler.cpp | 47 ++++++++++++++++++-
.../PGOProfile/memprof-undrift.test | 47 +++++++++++++++++++
2 files changed, 92 insertions(+), 2 deletions(-)
create mode 100644 llvm/test/Transforms/PGOProfile/memprof-undrift.test
diff --git a/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp b/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
index c980869a1c0d82..b416ef30f406bb 100644
--- a/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
@@ -171,6 +171,10 @@ static cl::opt<std::string>
cl::desc("The default memprof options"),
cl::Hidden, cl::init(""));
+static cl::opt<bool> UndriftProfile("memprof-undrift-profile",
+ cl::desc("Undrift MemProf profile"),
+ cl::init(false), cl::Hidden);
+
extern cl::opt<bool> MemProfReportHintedSizes;
// Instrumentation statistics
@@ -907,10 +911,38 @@ memprof::computeUndriftMap(Module &M, IndexedInstrProfReader *MemProfReader,
return UndriftMaps;
}
+// Given a MemProfRecord, undrift all the source locations present in the
+// record in place.
+static void
+undriftMemProfRecord(const DenseMap<uint64_t, LocToLocMap> &UndriftMaps,
+ memprof::MemProfRecord &MemProfRec) {
+ // Undrift a call stack in place.
+ auto UndriftCallStack = [&](std::vector<Frame> &CallStack) {
+ for (auto &F : CallStack) {
+ auto I = UndriftMaps.find(F.Function);
+ if (I == UndriftMaps.end())
+ continue;
+ auto J = I->second.find(LineLocation(F.LineOffset, F.Column));
+ if (J == I->second.end())
+ continue;
+ auto &NewLoc = J->second;
+ F.LineOffset = NewLoc.LineOffset;
+ F.Column = NewLoc.Column;
+ }
+ };
+
+ for (auto &AS : MemProfRec.AllocSites)
+ UndriftCallStack(AS.CallStack);
+
+ for (auto &CS : MemProfRec.CallSites)
+ UndriftCallStack(CS);
+}
+
static void
readMemprof(Module &M, Function &F, IndexedInstrProfReader *MemProfReader,
const TargetLibraryInfo &TLI,
- std::map<uint64_t, AllocMatchInfo> &FullStackIdToAllocMatchInfo) {
+ std::map<uint64_t, AllocMatchInfo> &FullStackIdToAllocMatchInfo,
+ DenseMap<uint64_t, LocToLocMap> &UndriftMaps) {
auto &Ctx = M.getContext();
// Previously we used getIRPGOFuncName() here. If F is local linkage,
// getIRPGOFuncName() returns FuncName with prefix 'FileName;'. But
@@ -958,6 +990,11 @@ readMemprof(Module &M, Function &F, IndexedInstrProfReader *MemProfReader,
NumOfMemProfFunc++;
+ // If requested, undrfit MemProfRecord so that the source locations in it
+ // match those in the IR.
+ if (UndriftProfile)
+ undriftMemProfRecord(UndriftMaps, *MemProfRec);
+
// Detect if there are non-zero column numbers in the profile. If not,
// treat all column numbers as 0 when matching (i.e. ignore any non-zero
// columns in the IR). The profiled binary might have been built with
@@ -1176,6 +1213,11 @@ PreservedAnalyses MemProfUsePass::run(Module &M, ModuleAnalysisManager &AM) {
auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
+ TargetLibraryInfo &TLI = FAM.getResult<TargetLibraryAnalysis>(*M.begin());
+ DenseMap<uint64_t, LocToLocMap> UndriftMaps;
+ if (UndriftProfile)
+ UndriftMaps = computeUndriftMap(M, MemProfReader.get(), TLI);
+
// Map from the stack has of each allocation context in the function profiles
// to the total profiled size (bytes), allocation type, and whether we matched
// it to an allocation in the IR.
@@ -1186,7 +1228,8 @@ PreservedAnalyses MemProfUsePass::run(Module &M, ModuleAnalysisManager &AM) {
continue;
const TargetLibraryInfo &TLI = FAM.getResult<TargetLibraryAnalysis>(F);
- readMemprof(M, F, MemProfReader.get(), TLI, FullStackIdToAllocMatchInfo);
+ readMemprof(M, F, MemProfReader.get(), TLI, FullStackIdToAllocMatchInfo,
+ UndriftMaps);
}
if (ClPrintMemProfMatchInfo) {
diff --git a/llvm/test/Transforms/PGOProfile/memprof-undrift.test b/llvm/test/Transforms/PGOProfile/memprof-undrift.test
new file mode 100644
index 00000000000000..db3c48db110b58
--- /dev/null
+++ b/llvm/test/Transforms/PGOProfile/memprof-undrift.test
@@ -0,0 +1,47 @@
+; REQUIRES: x86_64-linux
+
+; Make sure that we can undrift the MemProf profile and annotate the IR
+; accordingly.
+
+; RUN: split-file %s %t
+; RUN: llvm-profdata merge %t/memprof_annotate_yaml.yaml -o %t/memprof_annotate_yaml.memprofdata
+; RUN: opt < %t/memprof_annotate_yaml.ll -passes='memprof-use<profile-filename=%t/memprof_annotate_yaml.memprofdata>' -memprof-undrift-profile -S 2>&1 | FileCheck %s
+
+;--- memprof_annotate_yaml.yaml
+---
+HeapProfileRecords:
+ - GUID: _Z3foov
+ AllocSites:
+ - Callstack:
+ - { Function: _Z3foov, LineOffset: 3, Column: 30, IsInlineFrame: false }
+ - { Function: main, LineOffset: 2, Column: 5, IsInlineFrame: false }
+ MemInfoBlock:
+ # With these numbers, llvm::memprof::getAllocType will determine that
+ # the call to new is cold. See MemoryProfileInfo.cpp for details.
+ TotalSize: 400
+ AllocCount: 1
+ TotalLifetimeAccessDensity: 1
+ TotalLifetime: 1000000
+ CallSites: []
+...
+;--- memprof_annotate_yaml.ll
+define dso_local ptr @_Z3foov() !dbg !4 {
+entry:
+ %call = call ptr @_Znam(i64 4) #0, !dbg !5
+; CHECK: call ptr @_Znam(i64 4) #[[ATTR:[0-9]+]],
+ ret ptr %call
+}
+
+declare ptr @_Znam(i64)
+
+attributes #0 = { builtin allocsize(0) }
+; CHECK: attributes #[[ATTR]] = {{.*}} "memprof"="cold"
+
+!llvm.module.flags = !{!2, !3}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1)
+!1 = !DIFile(filename: "t", directory: "/")
+!2 = !{i32 7, !"Dwarf Version", i32 5}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 1, unit: !0)
+!5 = !DILocation(line: 1, column: 22, scope: !4)
>From a8fa34b30e2c63d4dc49ad0c87a5ccf88296b0fd Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Mon, 16 Dec 2024 19:55:21 -0800
Subject: [PATCH 2/3] Address comments.
---
.../PGOProfile/memprof-undrift.test | 48 ++++++++++++++-----
1 file changed, 37 insertions(+), 11 deletions(-)
diff --git a/llvm/test/Transforms/PGOProfile/memprof-undrift.test b/llvm/test/Transforms/PGOProfile/memprof-undrift.test
index db3c48db110b58..071c70015e4bcc 100644
--- a/llvm/test/Transforms/PGOProfile/memprof-undrift.test
+++ b/llvm/test/Transforms/PGOProfile/memprof-undrift.test
@@ -13,35 +13,61 @@ HeapProfileRecords:
- GUID: _Z3foov
AllocSites:
- Callstack:
- - { Function: _Z3foov, LineOffset: 3, Column: 30, IsInlineFrame: false }
+ - { Function: _Z3foov, LineOffset: 10, Column: 50, IsInlineFrame: true }
+ - { Function: _Z3barv, LineOffset: 20, Column: 30, IsInlineFrame: false }
- { Function: main, LineOffset: 2, Column: 5, IsInlineFrame: false }
MemInfoBlock:
- # With these numbers, llvm::memprof::getAllocType will determine that
- # the call to new is cold. See MemoryProfileInfo.cpp for details.
- TotalSize: 400
AllocCount: 1
- TotalLifetimeAccessDensity: 1
+ TotalSize: 400
TotalLifetime: 1000000
+ TotalLifetimeAccessDensity: 1
CallSites: []
+ - GUID: _Z3barv
+ AllocSites:
+ - Callstack:
+ - { Function: _Z3foov, LineOffset: 10, Column: 50, IsInlineFrame: true }
+ - { Function: _Z3barv, LineOffset: 20, Column: 30, IsInlineFrame: false }
+ - { Function: main, LineOffset: 2, Column: 5, IsInlineFrame: false }
+ MemInfoBlock:
+ AllocCount: 1
+ TotalSize: 400
+ TotalLifetime: 1000000
+ TotalLifetimeAccessDensity: 1
+ CallSites:
+ - - { Function: _Z3foov, LineOffset: 10, Column: 50, IsInlineFrame: true }
+ - { Function: _Z3barv, LineOffset: 20, Column: 30, IsInlineFrame: false }
...
;--- memprof_annotate_yaml.ll
define dso_local ptr @_Z3foov() !dbg !4 {
+; CHECK-LABEL: @_Z3foov
entry:
%call = call ptr @_Znam(i64 4) #0, !dbg !5
-; CHECK: call ptr @_Znam(i64 4) #[[ATTR:[0-9]+]],
+; CHECK: = call {{.*}} #[[ATTR:[0-9]+]]
ret ptr %call
}
-declare ptr @_Znam(i64)
+declare ptr @_Znam(i64 noundef)
+
+define dso_local ptr @_Z3barv() !dbg !6 {
+; CHECK-LABEL: @_Z3barv
+entry:
+ %call.i = call ptr @_Znam(i64 4) #0, !dbg !7
+; CHECK: = call {{.*}} #[[ATTR]]
+ ret ptr %call.i
+}
attributes #0 = { builtin allocsize(0) }
-; CHECK: attributes #[[ATTR]] = {{.*}} "memprof"="cold"
+; CHECK: attributes #[[ATTR]] = { builtin allocsize(0) "memprof"="cold" }
+!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2, !3}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1)
-!1 = !DIFile(filename: "t", directory: "/")
+!1 = !DIFile(filename: "undrift.cc", directory: "/")
!2 = !{i32 7, !"Dwarf Version", i32 5}
!3 = !{i32 2, !"Debug Info Version", i32 3}
-!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 1, unit: !0)
-!5 = !DILocation(line: 1, column: 22, scope: !4)
+!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 55, unit: !0)
+!5 = !DILocation(line: 55, column: 53, scope: !4)
+!6 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 56, unit: !0)
+!7 = !DILocation(line: 55, column: 53, scope: !4, inlinedAt: !8)
+!8 = distinct !DILocation(line: 56, column: 22, scope: !6)
>From 491042ed7cc82063c2e3f006e033d0caaa420f3f Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Tue, 17 Dec 2024 13:06:41 -0800
Subject: [PATCH 3/3] Rename the option to memprof-salvage-stale-profile.
---
llvm/lib/Transforms/Instrumentation/MemProfiler.cpp | 11 ++++++-----
llvm/test/Transforms/PGOProfile/memprof-undrift.test | 2 +-
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp b/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
index b416ef30f406bb..729cf8f42bc449 100644
--- a/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
@@ -171,9 +171,10 @@ static cl::opt<std::string>
cl::desc("The default memprof options"),
cl::Hidden, cl::init(""));
-static cl::opt<bool> UndriftProfile("memprof-undrift-profile",
- cl::desc("Undrift MemProf profile"),
- cl::init(false), cl::Hidden);
+static cl::opt<bool>
+ SalvageStaleProfile("memprof-salvage-stale-profile",
+ cl::desc("Salvage stale MemProf profile"),
+ cl::init(false), cl::Hidden);
extern cl::opt<bool> MemProfReportHintedSizes;
@@ -992,7 +993,7 @@ readMemprof(Module &M, Function &F, IndexedInstrProfReader *MemProfReader,
// If requested, undrfit MemProfRecord so that the source locations in it
// match those in the IR.
- if (UndriftProfile)
+ if (SalvageStaleProfile)
undriftMemProfRecord(UndriftMaps, *MemProfRec);
// Detect if there are non-zero column numbers in the profile. If not,
@@ -1215,7 +1216,7 @@ PreservedAnalyses MemProfUsePass::run(Module &M, ModuleAnalysisManager &AM) {
TargetLibraryInfo &TLI = FAM.getResult<TargetLibraryAnalysis>(*M.begin());
DenseMap<uint64_t, LocToLocMap> UndriftMaps;
- if (UndriftProfile)
+ if (SalvageStaleProfile)
UndriftMaps = computeUndriftMap(M, MemProfReader.get(), TLI);
// Map from the stack has of each allocation context in the function profiles
diff --git a/llvm/test/Transforms/PGOProfile/memprof-undrift.test b/llvm/test/Transforms/PGOProfile/memprof-undrift.test
index 071c70015e4bcc..bf5f115f78b608 100644
--- a/llvm/test/Transforms/PGOProfile/memprof-undrift.test
+++ b/llvm/test/Transforms/PGOProfile/memprof-undrift.test
@@ -5,7 +5,7 @@
; RUN: split-file %s %t
; RUN: llvm-profdata merge %t/memprof_annotate_yaml.yaml -o %t/memprof_annotate_yaml.memprofdata
-; RUN: opt < %t/memprof_annotate_yaml.ll -passes='memprof-use<profile-filename=%t/memprof_annotate_yaml.memprofdata>' -memprof-undrift-profile -S 2>&1 | FileCheck %s
+; RUN: opt < %t/memprof_annotate_yaml.ll -passes='memprof-use<profile-filename=%t/memprof_annotate_yaml.memprofdata>' -memprof-salvage-stale-profile -S 2>&1 | FileCheck %s
;--- memprof_annotate_yaml.yaml
---
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