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BoundsChecking: add a couple of simple tests and fix a bug in branch emition

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157329 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nuno Lopes
2012-05-23 16:24:52 +00:00
parent ee8100d70a
commit 2b52630094
2 changed files with 97 additions and 7 deletions
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26
lib/Transforms/Scalar/BoundsChecking.cpp
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@@ -62,6 +62,7 @@ namespace {
unsigned Penalty;
BasicBlock *getTrapBB();
void emitBranchToTrap(Value *Cmp = 0);
ConstTriState computeAllocSize(Value *Alloc, uint64_t &Size,
Value* &SizeValue);
bool instrument(Value *Ptr, Value *Val);
@@ -94,6 +95,22 @@ BasicBlock *BoundsChecking::getTrapBB() {
}
/// emitBranchToTrap - emit a branch instruction to a trap block.
/// If Cmp is non-null, perform a jump only if its value evaluates to true.
void BoundsChecking::emitBranchToTrap(Value *Cmp) {
Instruction *Inst = Builder->GetInsertPoint();
BasicBlock *OldBB = Inst->getParent();
BasicBlock *Cont = OldBB->splitBasicBlock(Inst);
OldBB->getTerminator()->eraseFromParent();
// FIXME: add unlikely branch taken metadata?
if (Cmp)
BranchInst::Create(getTrapBB(), Cont, Cmp, OldBB);
else
BranchInst::Create(getTrapBB(), OldBB);
}
/// computeAllocSize - compute the object size allocated by an allocation
/// site. Returns NotConst if the size is not constant (in SizeValue), Const if
/// the size is constant (in Size), and Dunno if the size could not be
@@ -254,7 +271,7 @@ bool BoundsChecking::instrument(Value *Ptr, Value *InstVal) {
if (!OffsetValue && ConstAlloc == Const) {
if (Size < Offset || (Size - Offset) < NeededSize) {
// Out of bounds
Builder->CreateBr(getTrapBB());
emitBranchToTrap();
++ChecksAdded;
return true;
}
@@ -278,13 +295,8 @@ bool BoundsChecking::instrument(Value *Ptr, Value *InstVal) {
Value *Cmp1 = Builder->CreateICmpULT(SizeValue, OffsetValue);
Value *Cmp2 = Builder->CreateICmpULT(ObjSize, NeededSizeVal);
Value *Or = Builder->CreateOr(Cmp1, Cmp2);
emitBranchToTrap(Or);
// FIXME: add unlikely branch taken metadata?
Instruction *Inst = Builder->GetInsertPoint();
BasicBlock *OldBB = Inst->getParent();
BasicBlock *Cont = OldBB->splitBasicBlock(Inst);
OldBB->getTerminator()->eraseFromParent();
BranchInst::Create(getTrapBB(), Cont, Or, OldBB);
++ChecksAdded;
return true;
}