move the bounds checking pass to the instrumentation folder, where it belongs. I dunno why in the world I dropped it in the Scalar folder in the first place.
No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160587 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Instrumentation/BoundsChecking.cpp b/lib/Transforms/Instrumentation/BoundsChecking.cpp
new file mode 100644
index 0000000..09e0f14
--- /dev/null
+++ b/lib/Transforms/Instrumentation/BoundsChecking.cpp
@@ -0,0 +1,209 @@
+//===- BoundsChecking.cpp - Instrumentation for run-time bounds checking --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a pass that instruments the code to perform run-time
+// bounds checking on loads, stores, and other memory intrinsics.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "bounds-checking"
+#include "llvm/IRBuilder.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Pass.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/MemoryBuiltins.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/TargetFolder.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Instrumentation.h"
+using namespace llvm;
+
+static cl::opt<bool> SingleTrapBB("bounds-checking-single-trap",
+ cl::desc("Use one trap block per function"));
+
+STATISTIC(ChecksAdded, "Bounds checks added");
+STATISTIC(ChecksSkipped, "Bounds checks skipped");
+STATISTIC(ChecksUnable, "Bounds checks unable to add");
+
+typedef IRBuilder<true, TargetFolder> BuilderTy;
+
+namespace {
+ struct BoundsChecking : public FunctionPass {
+ static char ID;
+
+ BoundsChecking(unsigned _Penalty = 5) : FunctionPass(ID), Penalty(_Penalty){
+ initializeBoundsCheckingPass(*PassRegistry::getPassRegistry());
+ }
+
+ virtual bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<TargetData>();
+ }
+
+ private:
+ const TargetData *TD;
+ ObjectSizeOffsetEvaluator *ObjSizeEval;
+ BuilderTy *Builder;
+ Instruction *Inst;
+ BasicBlock *TrapBB;
+ unsigned Penalty;
+
+ BasicBlock *getTrapBB();
+ void emitBranchToTrap(Value *Cmp = 0);
+ bool computeAllocSize(Value *Ptr, APInt &Offset, Value* &OffsetValue,
+ APInt &Size, Value* &SizeValue);
+ bool instrument(Value *Ptr, Value *Val);
+ };
+}
+
+char BoundsChecking::ID = 0;
+INITIALIZE_PASS(BoundsChecking, "bounds-checking", "Run-time bounds checking",
+ false, false)
+
+
+/// getTrapBB - create a basic block that traps. All overflowing conditions
+/// branch to this block. There's only one trap block per function.
+BasicBlock *BoundsChecking::getTrapBB() {
+ if (TrapBB && SingleTrapBB)
+ return TrapBB;
+
+ Function *Fn = Inst->getParent()->getParent();
+ BasicBlock::iterator PrevInsertPoint = Builder->GetInsertPoint();
+ TrapBB = BasicBlock::Create(Fn->getContext(), "trap", Fn);
+ Builder->SetInsertPoint(TrapBB);
+
+ llvm::Value *F = Intrinsic::getDeclaration(Fn->getParent(), Intrinsic::trap);
+ CallInst *TrapCall = Builder->CreateCall(F);
+ TrapCall->setDoesNotReturn();
+ TrapCall->setDoesNotThrow();
+ TrapCall->setDebugLoc(Inst->getDebugLoc());
+ Builder->CreateUnreachable();
+
+ Builder->SetInsertPoint(PrevInsertPoint);
+ return TrapBB;
+}
+
+
+/// 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) {
+ // check if the comparison is always false
+ ConstantInt *C = dyn_cast_or_null<ConstantInt>(Cmp);
+ if (C) {
+ ++ChecksSkipped;
+ if (!C->getZExtValue())
+ return;
+ else
+ Cmp = 0; // unconditional branch
+ }
+
+ Instruction *Inst = Builder->GetInsertPoint();
+ BasicBlock *OldBB = Inst->getParent();
+ BasicBlock *Cont = OldBB->splitBasicBlock(Inst);
+ OldBB->getTerminator()->eraseFromParent();
+
+ if (Cmp)
+ BranchInst::Create(getTrapBB(), Cont, Cmp, OldBB);
+ else
+ BranchInst::Create(getTrapBB(), OldBB);
+}
+
+
+/// instrument - adds run-time bounds checks to memory accessing instructions.
+/// Ptr is the pointer that will be read/written, and InstVal is either the
+/// result from the load or the value being stored. It is used to determine the
+/// size of memory block that is touched.
+/// Returns true if any change was made to the IR, false otherwise.
+bool BoundsChecking::instrument(Value *Ptr, Value *InstVal) {
+ uint64_t NeededSize = TD->getTypeStoreSize(InstVal->getType());
+ DEBUG(dbgs() << "Instrument " << *Ptr << " for " << Twine(NeededSize)
+ << " bytes\n");
+
+ SizeOffsetEvalType SizeOffset = ObjSizeEval->compute(Ptr);
+
+ if (!ObjSizeEval->bothKnown(SizeOffset)) {
+ ++ChecksUnable;
+ return false;
+ }
+
+ Value *Size = SizeOffset.first;
+ Value *Offset = SizeOffset.second;
+ ConstantInt *SizeCI = dyn_cast<ConstantInt>(Size);
+
+ IntegerType *IntTy = TD->getIntPtrType(Inst->getContext());
+ Value *NeededSizeVal = ConstantInt::get(IntTy, NeededSize);
+
+ // three checks are required to ensure safety:
+ // . Offset >= 0 (since the offset is given from the base ptr)
+ // . Size >= Offset (unsigned)
+ // . Size - Offset >= NeededSize (unsigned)
+ //
+ // optimization: if Size >= 0 (signed), skip 1st check
+ // FIXME: add NSW/NUW here? -- we dont care if the subtraction overflows
+ Value *ObjSize = Builder->CreateSub(Size, Offset);
+ Value *Cmp2 = Builder->CreateICmpULT(Size, Offset);
+ Value *Cmp3 = Builder->CreateICmpULT(ObjSize, NeededSizeVal);
+ Value *Or = Builder->CreateOr(Cmp2, Cmp3);
+ if (!SizeCI || SizeCI->getValue().slt(0)) {
+ Value *Cmp1 = Builder->CreateICmpSLT(Offset, ConstantInt::get(IntTy, 0));
+ Or = Builder->CreateOr(Cmp1, Or);
+ }
+ emitBranchToTrap(Or);
+
+ ++ChecksAdded;
+ return true;
+}
+
+bool BoundsChecking::runOnFunction(Function &F) {
+ TD = &getAnalysis<TargetData>();
+
+ TrapBB = 0;
+ BuilderTy TheBuilder(F.getContext(), TargetFolder(TD));
+ Builder = &TheBuilder;
+ ObjectSizeOffsetEvaluator TheObjSizeEval(TD, F.getContext());
+ ObjSizeEval = &TheObjSizeEval;
+
+ // check HANDLE_MEMORY_INST in include/llvm/Instruction.def for memory
+ // touching instructions
+ std::vector<Instruction*> WorkList;
+ for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i) {
+ Instruction *I = &*i;
+ if (isa<LoadInst>(I) || isa<StoreInst>(I) || isa<AtomicCmpXchgInst>(I) ||
+ isa<AtomicRMWInst>(I))
+ WorkList.push_back(I);
+ }
+
+ bool MadeChange = false;
+ for (std::vector<Instruction*>::iterator i = WorkList.begin(),
+ e = WorkList.end(); i != e; ++i) {
+ Inst = *i;
+
+ Builder->SetInsertPoint(Inst);
+ if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
+ MadeChange |= instrument(LI->getPointerOperand(), LI);
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
+ MadeChange |= instrument(SI->getPointerOperand(), SI->getValueOperand());
+ } else if (AtomicCmpXchgInst *AI = dyn_cast<AtomicCmpXchgInst>(Inst)) {
+ MadeChange |= instrument(AI->getPointerOperand(),AI->getCompareOperand());
+ } else if (AtomicRMWInst *AI = dyn_cast<AtomicRMWInst>(Inst)) {
+ MadeChange |= instrument(AI->getPointerOperand(), AI->getValOperand());
+ } else {
+ llvm_unreachable("unknown Instruction type");
+ }
+ }
+ return MadeChange;
+}
+
+FunctionPass *llvm::createBoundsCheckingPass(unsigned Penalty) {
+ return new BoundsChecking(Penalty);
+}