[clang] [clang] Add optional pass to remove UBSAN traps using PGO (PR #84214)
Vitaly Buka via cfe-commits
cfe-commits at lists.llvm.org
Fri Mar 8 21:57:39 PST 2024
https://github.com/vitalybuka updated https://github.com/llvm/llvm-project/pull/84214
>From feb5bfa786d1660a7fe0b6c48ec9048cdd315800 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Wed, 6 Mar 2024 10:03:46 -0800
Subject: [PATCH 1/4] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
=?UTF-8?q?itial=20version?=
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Created using spr 1.3.4
---
clang/lib/CodeGen/BackendUtil.cpp | 17 +++++++++++++++++
clang/test/CodeGen/remote-traps.cpp | 15 +++++++++++++++
2 files changed, 32 insertions(+)
create mode 100644 clang/test/CodeGen/remote-traps.cpp
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 7310e3817c79a1..d89e53f69c4a51 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -76,6 +76,7 @@
#include "llvm/Transforms/Instrumentation/MemProfiler.h"
#include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
#include "llvm/Transforms/Instrumentation/PGOInstrumentation.h"
+#include "llvm/Transforms/Instrumentation/RemoveTrapsPass.h"
#include "llvm/Transforms/Instrumentation/SanitizerBinaryMetadata.h"
#include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
#include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
@@ -83,6 +84,7 @@
#include "llvm/Transforms/Scalar/EarlyCSE.h"
#include "llvm/Transforms/Scalar/GVN.h"
#include "llvm/Transforms/Scalar/JumpThreading.h"
+#include "llvm/Transforms/Scalar/SimplifyCFG.h"
#include "llvm/Transforms/Utils/Debugify.h"
#include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
@@ -98,6 +100,10 @@ using namespace llvm;
namespace llvm {
extern cl::opt<bool> PrintPipelinePasses;
+cl::opt<bool> ClRemoveTraps("clang-remove-traps", cl::Optional,
+ cl::desc("Insert remove-traps pass."),
+ cl::init(false));
+
// Experiment to move sanitizers earlier.
static cl::opt<bool> ClSanitizeOnOptimizerEarlyEP(
"sanitizer-early-opt-ep", cl::Optional,
@@ -744,6 +750,17 @@ static void addSanitizers(const Triple &TargetTriple,
// LastEP does not need GlobalsAA.
PB.registerOptimizerLastEPCallback(SanitizersCallback);
}
+
+ if (ClRemoveTraps) {
+ PB.registerOptimizerEarlyEPCallback([&](ModulePassManager &MPM,
+ OptimizationLevel Level) {
+ FunctionPassManager FPM;
+ FPM.addPass(RemoveTrapsPass());
+ FPM.addPass(
+ SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
+ MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
+ });
+ }
}
void EmitAssemblyHelper::RunOptimizationPipeline(
diff --git a/clang/test/CodeGen/remote-traps.cpp b/clang/test/CodeGen/remote-traps.cpp
new file mode 100644
index 00000000000000..7d4eb76a7d81e9
--- /dev/null
+++ b/clang/test/CodeGen/remote-traps.cpp
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -O1 -emit-llvm -fsanitize=signed-integer-overflow -fsanitize-trap=signed-integer-overflow %s -o - | FileCheck %s
+// RUN: %clang_cc1 -O1 -emit-llvm -fsanitize=signed-integer-overflow -fsanitize-trap=signed-integer-overflow -mllvm -clang-remove-traps -mllvm -remove-traps-random-rate=1 %s -o - | FileCheck %s --implicit-check-not="call void @llvm.ubsantrap" --check-prefixes=REMOVE
+
+int f(int x) {
+ return x + 123;
+}
+
+// CHECK-LABEL: define dso_local noundef i32 @_Z1fi(
+// CHECK: call { i32, i1 } @llvm.sadd.with.overflow.i32(
+// CHECK: trap:
+// CHECK-NEXT: call void @llvm.ubsantrap(i8 0)
+// CHECK-NEXT: unreachable, !nosanitize !2
+
+// REMOVE-LABEL: define dso_local noundef i32 @_Z1fi(
+// REMOVE: call { i32, i1 } @llvm.sadd.with.overflow.i32(
>From 0b2b44e04b8c900c29f52e340ebdfc6824607773 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Wed, 6 Mar 2024 10:08:47 -0800
Subject: [PATCH 2/4] comment
Created using spr 1.3.4
---
clang/lib/CodeGen/BackendUtil.cpp | 3 +++
1 file changed, 3 insertions(+)
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index d89e53f69c4a51..fa49a364cf5600 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -752,6 +752,9 @@ static void addSanitizers(const Triple &TargetTriple,
}
if (ClRemoveTraps) {
+ // We can optimize after inliner, and PGO profile matching, which are part
+ // of `buildModuleSimplificationPipeline`. The hook below is called after
+ // that, from `buildModuleOptimizationPipeline`.
PB.registerOptimizerEarlyEPCallback([&](ModulePassManager &MPM,
OptimizationLevel Level) {
FunctionPassManager FPM;
>From 000854eb9d18cd9cfd6eaf7d29e5954fb18d454c Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Wed, 6 Mar 2024 10:22:16 -0800
Subject: [PATCH 3/4] comment
Created using spr 1.3.4
---
clang/lib/CodeGen/BackendUtil.cpp | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index fa49a364cf5600..55a45022c7cb17 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -752,9 +752,10 @@ static void addSanitizers(const Triple &TargetTriple,
}
if (ClRemoveTraps) {
- // We can optimize after inliner, and PGO profile matching, which are part
- // of `buildModuleSimplificationPipeline`. The hook below is called after
- // that, from `buildModuleOptimizationPipeline`.
+ // We can optimize after inliner, and PGO profile matching. The hook below
+ // is called from `buildModuleOptimizationPipeline` just after profile use,
+ // and inliner is a part of `buildModuleSimplificationPipeline`, which is
+ // before `buildModuleOptimizationPipeline`.
PB.registerOptimizerEarlyEPCallback([&](ModulePassManager &MPM,
OptimizationLevel Level) {
FunctionPassManager FPM;
>From d1b8488dd73d39ddc5124c9ecd72e72f128af1f8 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Fri, 8 Mar 2024 21:57:19 -0800
Subject: [PATCH 4/4] Use ScalarOptimizerLateEPCallback
Created using spr 1.3.4
---
clang/lib/CodeGen/BackendUtil.cpp | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index a8c374c89b0936..e0c4b3b12b9b46 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -753,17 +753,15 @@ static void addSanitizers(const Triple &TargetTriple,
if (ClRemoveTraps) {
// We can optimize after inliner, and PGO profile matching. The hook below
- // is called from `buildModuleOptimizationPipeline` just after profile use,
- // and inliner is a part of `buildModuleSimplificationPipeline`, which is
- // before `buildModuleOptimizationPipeline`.
- PB.registerOptimizerEarlyEPCallback([](ModulePassManager &MPM,
- OptimizationLevel Level) {
- FunctionPassManager FPM;
- FPM.addPass(RemoveTrapsPass());
- FPM.addPass(
- SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
- MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
- });
+ // is called at the end `buildFunctionSimplificationPipeline`, which called
+ // from `buildInlinerPipeline`, which called after profile matching.
+ PB.registerScalarOptimizerLateEPCallback(
+ [](FunctionPassManager &FPM, OptimizationLevel Level) {
+ // RemoveTrapsPass expects trap blocks precedded by conditional
+ // branches, which often is not the case without SimplifyCFG.
+ FPM.addPass(SimplifyCFGPass());
+ FPM.addPass(RemoveTrapsPass());
+ });
}
}
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