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[HWASAN] Emit optimization remarks #88332

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Merged
merged 1 commit into from
Apr 11, 2024
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[HWASAN] Emit optimization remarks #88332

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50 changes: 35 additions & 15 deletions llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/DomTreeUpdater.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/StackSafetyAnalysis.h"
Expand Down Expand Up @@ -1492,23 +1493,42 @@ bool HWAddressSanitizer::instrumentStack(memtag::StackInfo &SInfo,
return true;
}

static void emitRemark(const Function &F, OptimizationRemarkEmitter &ORE,
bool Skip) {
if (Skip) {
ORE.emit([&]() {
return OptimizationRemark(DEBUG_TYPE, "Skip", &F)
<< "Skipped: F=" << ore::NV("Function", &F);
});
} else {
ORE.emit([&]() {
return OptimizationRemarkMissed(DEBUG_TYPE, "Sanitize", &F)
<< "Sanitized: F=" << ore::NV("Function", &F);
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@fmayer fmayer Jun 6, 2024 •
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Why do we need this arg? We already have the F in the output either way.

Now the output looks like this

--- !Missed
Pass:            hwasan
Name:            Sanitize
Function:        test_retptr
Args:
  - String:          'Sanitized: F='
  - Function:        test_retptr
...

I suggest just making this OptimizationRemarkMissed(DEBUG_TYPE, "Sanitize", &F); Same above

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Also, wouldn't it be better to have the same name for the Skip and non skip-Cases, and just distinguish by the Miss / Pass

});
}
}

bool HWAddressSanitizer::selectiveInstrumentationShouldSkip(
Function &F, FunctionAnalysisManager &FAM) const {
if (ClRandomSkipRate.getNumOccurrences()) {
std::bernoulli_distribution D(ClRandomSkipRate);
return !D(*Rng);
}
if (!ClHotPercentileCutoff.getNumOccurrences())
return false;
auto &MAMProxy = FAM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
ProfileSummaryInfo *PSI =
MAMProxy.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
if (!PSI || !PSI->hasProfileSummary()) {
++NumNoProfileSummaryFuncs;
return false;
}
return PSI->isFunctionHotInCallGraphNthPercentile(
ClHotPercentileCutoff, &F, FAM.getResult<BlockFrequencyAnalysis>(F));
bool Skip = [&]() {
if (ClRandomSkipRate.getNumOccurrences()) {
std::bernoulli_distribution D(ClRandomSkipRate);
return !D(*Rng);
}
if (!ClHotPercentileCutoff.getNumOccurrences())
return false;
auto &MAMProxy = FAM.getResult<ModuleAnalysisManagerFunctionProxy>(F);
ProfileSummaryInfo *PSI =
MAMProxy.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
if (!PSI || !PSI->hasProfileSummary()) {
++NumNoProfileSummaryFuncs;
return false;
}
return PSI->isFunctionHotInCallGraphNthPercentile(
ClHotPercentileCutoff, &F, FAM.getResult<BlockFrequencyAnalysis>(F));
}();
emitRemark(F, FAM.getResult<OptimizationRemarkEmitterAnalysis>(F), Skip);
return Skip;
}

void HWAddressSanitizer::sanitizeFunction(Function &F,
Expand Down
12 changes: 8 additions & 4 deletions llvm/test/Instrumentation/HWAddressSanitizer/pgo-opt-out.ll
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Original file line number Diff line number Diff line change
@@ -1,17 +1,21 @@
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -S -hwasan-percentile-cutoff-hot=700000 | FileCheck %s --check-prefix=HOT70
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -S -hwasan-percentile-cutoff-hot=990000 | FileCheck %s --check-prefix=HOT99
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -S -hwasan-random-rate=1.0 | FileCheck %s --check-prefix=ALL
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -S -hwasan-random-rate=0.0 | FileCheck %s --check-prefix=NONE
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -pass-remarks=hwasan -pass-remarks-missed=hwasan -S -hwasan-percentile-cutoff-hot=700000 2>&1 | FileCheck %s --check-prefix=HOT70
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -pass-remarks=hwasan -pass-remarks-missed=hwasan -S -hwasan-percentile-cutoff-hot=990000 2>&1 | FileCheck %s --check-prefix=HOT99
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -pass-remarks=hwasan -pass-remarks-missed=hwasan -S -hwasan-random-rate=1.0 2>&1 | FileCheck %s --check-prefix=ALL
; RUN: opt < %s -passes='require<profile-summary>,hwasan' -pass-remarks=hwasan -pass-remarks-missed=hwasan -S -hwasan-random-rate=0.0 2>&1 | FileCheck %s --check-prefix=NONE

; HOT70: remark: <unknown>:0:0: Sanitized: F=sanitized
; HOT70: @sanitized
; HOT70-NEXT: @__hwasan_tls

; HOT99: remark: <unknown>:0:0: Skipped: F=sanitized
; HOT99: @sanitized
; HOT99-NEXT: %x = alloca i8, i64 4

; ALL: remark: <unknown>:0:0: Sanitized: F=sanitize
; ALL: @sanitized
; ALL-NEXT: @__hwasan_tls

; NONE: remark: <unknown>:0:0: Skipped: F=sanitized
; NONE: @sanitized
; NONE-NEXT: %x = alloca i8, i64 4

Expand Down