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Move SplitBlockAndInsertIfThen to BasicBlockUtils.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166278 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evgeniy Stepanov 2012-10-19 10:48:31 +00:00
parent 17f68c52d2
commit 4a2dec05ce
3 changed files with 68 additions and 35 deletions
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25
include/llvm/Transforms/Utils/BasicBlockUtils.h
View File

@ -25,9 +25,11 @@ namespace llvm {
class AliasAnalysis;
class Instruction;
class MDNode;
class Pass;
class ReturnInst;
class TargetLibraryInfo;
class TerminatorInst;
/// DeleteDeadBlock - Delete the specified block, which must have no
/// predecessors.
@ -203,6 +205,29 @@ void SplitLandingPadPredecessors(BasicBlock *OrigBB,ArrayRef<BasicBlock*> Preds,
ReturnInst *FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
BasicBlock *Pred);
/// SplitBlockAndInsertIfThen - Split the containing block at the
/// specified instruction - everything before and including Cmp stays
/// in the old basic block, and everything after Cmp is moved to a
/// new block. The two blocks are connected by a conditional branch
/// (with value of Cmp being the condition).
/// Before:
/// Head
/// Cmp
/// Tail
/// After:
/// Head
/// Cmp
/// if (Cmp)
/// ThenBlock
/// Tail
///
/// If Unreachable is true, then ThenBlock ends with
/// UnreachableInst, otherwise it branches to Tail.
/// Returns the NewBasicBlock's terminator.
TerminatorInst *SplitBlockAndInsertIfThen(Instruction *Cmp,
bool Unreachable, MDNode *BranchWeights = 0);
} // End llvm namespace
#endif

39
lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -245,38 +245,6 @@ static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
GlobalValue::PrivateLinkage, StrConst, "");
}
// Split the basic block and insert an if-then code.
// Before:
// Head
// Cmp
// Tail
// After:
// Head
// if (Cmp)
// ThenBlock
// Tail
//
// ThenBlock block is created and its terminator is returned.
// If Unreachable, ThenBlock is terminated with UnreachableInst, otherwise
// it is terminated with BranchInst to Tail.
static TerminatorInst *splitBlockAndInsertIfThen(Value *Cmp, bool Unreachable) {
Instruction *SplitBefore = cast<Instruction>(Cmp)->getNextNode();
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Tail = Head->splitBasicBlock(SplitBefore);
TerminatorInst *HeadOldTerm = Head->getTerminator();
LLVMContext &C = Head->getParent()->getParent()->getContext();
BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
TerminatorInst *CheckTerm;
if (Unreachable)
CheckTerm = new UnreachableInst(C, ThenBlock);
else
CheckTerm = BranchInst::Create(Tail, ThenBlock);
BranchInst *HeadNewTerm =
BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp);
ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
return CheckTerm;
}
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
// Shadow >> scale
Shadow = IRB.CreateLShr(Shadow, MappingScale);
@ -324,7 +292,7 @@ bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
Value *Cmp = IRB.CreateICmpNE(Length,
Constant::getNullValue(Length->getType()));
InsertBefore = splitBlockAndInsertIfThen(Cmp, false);
InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
}
instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
@ -480,7 +448,8 @@ void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
TerminatorInst *CrashTerm = 0;
if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
TerminatorInst *CheckTerm = splitBlockAndInsertIfThen(Cmp, false);
TerminatorInst *CheckTerm =
SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
IRB.SetInsertPoint(CheckTerm);
@ -491,7 +460,7 @@ void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
ReplaceInstWithInst(CheckTerm, NewTerm);
} else {
CrashTerm = splitBlockAndInsertIfThen(Cmp, true);
CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
}
Instruction *Crash =

39
lib/Transforms/Utils/BasicBlockUtils.cpp
View File

@ -687,3 +687,42 @@ ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
return cast<ReturnInst>(NewRet);
}
/// SplitBlockAndInsertIfThen - Split the containing block at the
/// specified instruction - everything before and including Cmp stays
/// in the old basic block, and everything after Cmp is moved to a
/// new block. The two blocks are connected by a conditional branch
/// (with value of Cmp being the condition).
/// Before:
/// Head
/// Cmp
/// Tail
/// After:
/// Head
/// Cmp
/// if (Cmp)
/// ThenBlock
/// Tail
///
/// If Unreachable is true, then ThenBlock ends with
/// UnreachableInst, otherwise it branches to Tail.
/// Returns the NewBasicBlock's terminator.
TerminatorInst *llvm::SplitBlockAndInsertIfThen(Instruction *Cmp,
bool Unreachable, MDNode *BranchWeights) {
Instruction *SplitBefore = Cmp->getNextNode();
BasicBlock *Head = SplitBefore->getParent();
BasicBlock *Tail = Head->splitBasicBlock(SplitBefore);
TerminatorInst *HeadOldTerm = Head->getTerminator();
LLVMContext &C = Head->getContext();
BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
TerminatorInst *CheckTerm;
if (Unreachable)
CheckTerm = new UnreachableInst(C, ThenBlock);
else
CheckTerm = BranchInst::Create(Tail, ThenBlock);
BranchInst *HeadNewTerm =
BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp);
HeadNewTerm->setMetadata(LLVMContext::MD_prof, BranchWeights);
ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
return CheckTerm;
}