From 8055aff448f1505e764d60ab10f7a202ee702761 Mon Sep 17 00:00:00 2001 From: Luca Dariz Date: Fri, 5 Sep 2014 14:43:52 +0200 Subject: Detect overflow of unsigned add, sub and mul operations This requires clang with -fsanitize=unsigned-integer-overflow tested with clang and llvm 3.4.2 --- lib/Module/IntrinsicCleaner.cpp | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'lib/Module') diff --git a/lib/Module/IntrinsicCleaner.cpp b/lib/Module/IntrinsicCleaner.cpp index 0f095269..ebdbd3a6 100644 --- a/lib/Module/IntrinsicCleaner.cpp +++ b/lib/Module/IntrinsicCleaner.cpp @@ -117,6 +117,7 @@ bool IntrinsicCleanerPass::runOnBasicBlock(BasicBlock &b, Module &M) { } case Intrinsic::uadd_with_overflow: + case Intrinsic::usub_with_overflow: case Intrinsic::umul_with_overflow: { IRBuilder<> builder(ii->getParent(), ii); @@ -124,13 +125,18 @@ bool IntrinsicCleanerPass::runOnBasicBlock(BasicBlock &b, Module &M) { Value *op2 = ii->getArgOperand(1); Value *result = 0; - if (ii->getIntrinsicID() == Intrinsic::uadd_with_overflow) + Value *overflow = 0; + if (ii->getIntrinsicID() == Intrinsic::uadd_with_overflow){ result = builder.CreateAdd(op1, op2); - else + overflow = builder.CreateICmpULT(result, op1); + } else if (ii->getIntrinsicID() == Intrinsic::usub_with_overflow){ + result = builder.CreateSub(op1, op2); + overflow = builder.CreateICmpUGT(result, op1); + } else if (ii->getIntrinsicID() == Intrinsic::umul_with_overflow){ result = builder.CreateMul(op1, op2); + overflow = builder.CreateICmpULT(result, op1); + } - Value *overflow = builder.CreateICmpULT(result, op1); - Value *resultStruct = builder.CreateInsertValue(UndefValue::get(ii->getType()), result, 0); resultStruct = builder.CreateInsertValue(resultStruct, overflow, 1); -- cgit 1.4.1