llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-codegen Author: Vitaly Buka (vitalybuka) <details> <summary>Changes</summary> With #<!-- -->83470 it reduces UBSAN overhead from 52.5% to 12.6%. Measured as "Geomean difference" on "test-suite/MultiSource/Benchmarks" with PGO+ThinLTO build. On real server apps we see 95% of code instrumented, with 10% -> 1.5% UBSAN overhead improvements. We can pass this test only with subset of UBSAN, so base overhead is smaller. We have followup patches to improve it even further. --- Full diff: https://github.com/llvm/llvm-project/pull/84214.diff 2 Files Affected: - (modified) clang/lib/CodeGen/BackendUtil.cpp (+17) - (added) clang/test/CodeGen/remote-traps.cpp (+15) ``````````diff diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp index 056f790d41853d..6f9aa262f3d51e 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, @@ -743,6 +749,17 @@ 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( `````````` </details> https://github.com/llvm/llvm-project/pull/84214 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits