1 //===-- Lint.cpp - Check for common errors in LLVM IR ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass statically checks for common and easily-identified constructs
11 // which produce undefined or likely unintended behavior in LLVM IR.
13 // It is not a guarantee of correctness, in two ways. First, it isn't
14 // comprehensive. There are checks which could be done statically which are
15 // not yet implemented. Some of these are indicated by TODO comments, but
16 // those aren't comprehensive either. Second, many conditions cannot be
17 // checked statically. This pass does no dynamic instrumentation, so it
18 // can't check for all possible problems.
20 // Another limitation is that it assumes all code will be executed. A store
21 // through a null pointer in a basic block which is never reached is harmless,
22 // but this pass will warn about it anyway. This is the main reason why most
23 // of these checks live here instead of in the Verifier pass.
25 // Optimization passes may make conditions that this pass checks for more or
26 // less obvious. If an optimization pass appears to be introducing a warning,
27 // it may be that the optimization pass is merely exposing an existing
28 // condition in the code.
30 // This code may be run before instcombine. In many cases, instcombine checks
31 // for the same kinds of things and turns instructions with undefined behavior
32 // into unreachable (or equivalent). Because of this, this pass makes some
33 // effort to look through bitcasts and so on.
35 //===----------------------------------------------------------------------===//
37 #include "llvm/Analysis/Passes.h"
38 #include "llvm/Analysis/AliasAnalysis.h"
39 #include "llvm/Analysis/InstructionSimplify.h"
40 #include "llvm/Analysis/ConstantFolding.h"
41 #include "llvm/Analysis/Dominators.h"
42 #include "llvm/Analysis/Lint.h"
43 #include "llvm/Analysis/Loads.h"
44 #include "llvm/Analysis/ValueTracking.h"
45 #include "llvm/Assembly/Writer.h"
46 #include "llvm/Target/TargetData.h"
47 #include "llvm/Pass.h"
48 #include "llvm/PassManager.h"
49 #include "llvm/IntrinsicInst.h"
50 #include "llvm/Function.h"
51 #include "llvm/Support/CallSite.h"
52 #include "llvm/Support/Debug.h"
53 #include "llvm/Support/InstVisitor.h"
54 #include "llvm/Support/raw_ostream.h"
55 #include "llvm/ADT/STLExtras.h"
60 static unsigned Read = 1;
61 static unsigned Write = 2;
62 static unsigned Callee = 4;
63 static unsigned Branchee = 8;
66 class Lint : public FunctionPass, public InstVisitor<Lint> {
67 friend class InstVisitor<Lint>;
69 void visitFunction(Function &F);
71 void visitCallSite(CallSite CS);
72 void visitMemoryReference(Instruction &I, Value *Ptr,
73 unsigned Size, unsigned Align,
74 const Type *Ty, unsigned Flags);
76 void visitCallInst(CallInst &I);
77 void visitInvokeInst(InvokeInst &I);
78 void visitReturnInst(ReturnInst &I);
79 void visitLoadInst(LoadInst &I);
80 void visitStoreInst(StoreInst &I);
81 void visitXor(BinaryOperator &I);
82 void visitSub(BinaryOperator &I);
83 void visitLShr(BinaryOperator &I);
84 void visitAShr(BinaryOperator &I);
85 void visitShl(BinaryOperator &I);
86 void visitSDiv(BinaryOperator &I);
87 void visitUDiv(BinaryOperator &I);
88 void visitSRem(BinaryOperator &I);
89 void visitURem(BinaryOperator &I);
90 void visitAllocaInst(AllocaInst &I);
91 void visitVAArgInst(VAArgInst &I);
92 void visitIndirectBrInst(IndirectBrInst &I);
93 void visitExtractElementInst(ExtractElementInst &I);
94 void visitInsertElementInst(InsertElementInst &I);
95 void visitUnreachableInst(UnreachableInst &I);
97 Value *findValue(Value *V, bool OffsetOk) const;
98 Value *findValueImpl(Value *V, bool OffsetOk,
99 SmallPtrSet<Value *, 4> &Visited) const;
107 std::string Messages;
108 raw_string_ostream MessagesStr;
110 static char ID; // Pass identification, replacement for typeid
111 Lint() : FunctionPass(ID), MessagesStr(Messages) {}
113 virtual bool runOnFunction(Function &F);
115 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
116 AU.setPreservesAll();
117 AU.addRequired<AliasAnalysis>();
118 AU.addRequired<DominatorTree>();
120 virtual void print(raw_ostream &O, const Module *M) const {}
122 void WriteValue(const Value *V) {
124 if (isa<Instruction>(V)) {
125 MessagesStr << *V << '\n';
127 WriteAsOperand(MessagesStr, V, true, Mod);
132 // CheckFailed - A check failed, so print out the condition and the message
133 // that failed. This provides a nice place to put a breakpoint if you want
134 // to see why something is not correct.
135 void CheckFailed(const Twine &Message,
136 const Value *V1 = 0, const Value *V2 = 0,
137 const Value *V3 = 0, const Value *V4 = 0) {
138 MessagesStr << Message.str() << "\n";
148 INITIALIZE_PASS_BEGIN(Lint, "lint", "Statically lint-checks LLVM IR",
150 INITIALIZE_PASS_DEPENDENCY(DominatorTree)
151 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
152 INITIALIZE_PASS_END(Lint, "lint", "Statically lint-checks LLVM IR",
155 // Assert - We know that cond should be true, if not print an error message.
156 #define Assert(C, M) \
157 do { if (!(C)) { CheckFailed(M); return; } } while (0)
158 #define Assert1(C, M, V1) \
159 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
160 #define Assert2(C, M, V1, V2) \
161 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
162 #define Assert3(C, M, V1, V2, V3) \
163 do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
164 #define Assert4(C, M, V1, V2, V3, V4) \
165 do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
167 // Lint::run - This is the main Analysis entry point for a
170 bool Lint::runOnFunction(Function &F) {
172 AA = &getAnalysis<AliasAnalysis>();
173 DT = &getAnalysis<DominatorTree>();
174 TD = getAnalysisIfAvailable<TargetData>();
176 dbgs() << MessagesStr.str();
181 void Lint::visitFunction(Function &F) {
182 // This isn't undefined behavior, it's just a little unusual, and it's a
183 // fairly common mistake to neglect to name a function.
184 Assert1(F.hasName() || F.hasLocalLinkage(),
185 "Unusual: Unnamed function with non-local linkage", &F);
187 // TODO: Check for irreducible control flow.
190 void Lint::visitCallSite(CallSite CS) {
191 Instruction &I = *CS.getInstruction();
192 Value *Callee = CS.getCalledValue();
194 visitMemoryReference(I, Callee, AliasAnalysis::UnknownSize,
195 0, 0, MemRef::Callee);
197 if (Function *F = dyn_cast<Function>(findValue(Callee, /*OffsetOk=*/false))) {
198 Assert1(CS.getCallingConv() == F->getCallingConv(),
199 "Undefined behavior: Caller and callee calling convention differ",
202 const FunctionType *FT = F->getFunctionType();
203 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
205 Assert1(FT->isVarArg() ?
206 FT->getNumParams() <= NumActualArgs :
207 FT->getNumParams() == NumActualArgs,
208 "Undefined behavior: Call argument count mismatches callee "
209 "argument count", &I);
211 Assert1(FT->getReturnType() == I.getType(),
212 "Undefined behavior: Call return type mismatches "
213 "callee return type", &I);
215 // Check argument types (in case the callee was casted) and attributes.
216 // TODO: Verify that caller and callee attributes are compatible.
217 Function::arg_iterator PI = F->arg_begin(), PE = F->arg_end();
218 CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
219 for (; AI != AE; ++AI) {
222 Argument *Formal = PI++;
223 Assert1(Formal->getType() == Actual->getType(),
224 "Undefined behavior: Call argument type mismatches "
225 "callee parameter type", &I);
227 // Check that noalias arguments don't alias other arguments. The
228 // AliasAnalysis API isn't expressive enough for what we really want
229 // to do. Known partial overlap is not distinguished from the case
230 // where nothing is known.
231 if (Formal->hasNoAliasAttr() && Actual->getType()->isPointerTy())
232 for (CallSite::arg_iterator BI = CS.arg_begin(); BI != AE; ++BI) {
233 Assert1(AI == BI || AA->alias(*AI, *BI) != AliasAnalysis::MustAlias,
234 "Unusual: noalias argument aliases another argument", &I);
237 // Check that an sret argument points to valid memory.
238 if (Formal->hasStructRetAttr() && Actual->getType()->isPointerTy()) {
240 cast<PointerType>(Formal->getType())->getElementType();
241 visitMemoryReference(I, Actual, AA->getTypeStoreSize(Ty),
242 TD ? TD->getABITypeAlignment(Ty) : 0,
243 Ty, MemRef::Read | MemRef::Write);
249 if (CS.isCall() && cast<CallInst>(CS.getInstruction())->isTailCall())
250 for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
252 Value *Obj = findValue(*AI, /*OffsetOk=*/true);
253 Assert1(!isa<AllocaInst>(Obj),
254 "Undefined behavior: Call with \"tail\" keyword references "
259 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I))
260 switch (II->getIntrinsicID()) {
263 // TODO: Check more intrinsics
265 case Intrinsic::memcpy: {
266 MemCpyInst *MCI = cast<MemCpyInst>(&I);
267 // TODO: If the size is known, use it.
268 visitMemoryReference(I, MCI->getDest(), AliasAnalysis::UnknownSize,
269 MCI->getAlignment(), 0,
271 visitMemoryReference(I, MCI->getSource(), AliasAnalysis::UnknownSize,
272 MCI->getAlignment(), 0,
275 // Check that the memcpy arguments don't overlap. The AliasAnalysis API
276 // isn't expressive enough for what we really want to do. Known partial
277 // overlap is not distinguished from the case where nothing is known.
279 if (const ConstantInt *Len =
280 dyn_cast<ConstantInt>(findValue(MCI->getLength(),
281 /*OffsetOk=*/false)))
282 if (Len->getValue().isIntN(32))
283 Size = Len->getValue().getZExtValue();
284 Assert1(AA->alias(MCI->getSource(), Size, MCI->getDest(), Size) !=
285 AliasAnalysis::MustAlias,
286 "Undefined behavior: memcpy source and destination overlap", &I);
289 case Intrinsic::memmove: {
290 MemMoveInst *MMI = cast<MemMoveInst>(&I);
291 // TODO: If the size is known, use it.
292 visitMemoryReference(I, MMI->getDest(), AliasAnalysis::UnknownSize,
293 MMI->getAlignment(), 0,
295 visitMemoryReference(I, MMI->getSource(), AliasAnalysis::UnknownSize,
296 MMI->getAlignment(), 0,
300 case Intrinsic::memset: {
301 MemSetInst *MSI = cast<MemSetInst>(&I);
302 // TODO: If the size is known, use it.
303 visitMemoryReference(I, MSI->getDest(), AliasAnalysis::UnknownSize,
304 MSI->getAlignment(), 0,
309 case Intrinsic::vastart:
310 Assert1(I.getParent()->getParent()->isVarArg(),
311 "Undefined behavior: va_start called in a non-varargs function",
314 visitMemoryReference(I, CS.getArgument(0), AliasAnalysis::UnknownSize,
315 0, 0, MemRef::Read | MemRef::Write);
317 case Intrinsic::vacopy:
318 visitMemoryReference(I, CS.getArgument(0), AliasAnalysis::UnknownSize,
319 0, 0, MemRef::Write);
320 visitMemoryReference(I, CS.getArgument(1), AliasAnalysis::UnknownSize,
323 case Intrinsic::vaend:
324 visitMemoryReference(I, CS.getArgument(0), AliasAnalysis::UnknownSize,
325 0, 0, MemRef::Read | MemRef::Write);
328 case Intrinsic::stackrestore:
329 // Stackrestore doesn't read or write memory, but it sets the
330 // stack pointer, which the compiler may read from or write to
331 // at any time, so check it for both readability and writeability.
332 visitMemoryReference(I, CS.getArgument(0), AliasAnalysis::UnknownSize,
333 0, 0, MemRef::Read | MemRef::Write);
338 void Lint::visitCallInst(CallInst &I) {
339 return visitCallSite(&I);
342 void Lint::visitInvokeInst(InvokeInst &I) {
343 return visitCallSite(&I);
346 void Lint::visitReturnInst(ReturnInst &I) {
347 Function *F = I.getParent()->getParent();
348 Assert1(!F->doesNotReturn(),
349 "Unusual: Return statement in function with noreturn attribute",
352 if (Value *V = I.getReturnValue()) {
353 Value *Obj = findValue(V, /*OffsetOk=*/true);
354 Assert1(!isa<AllocaInst>(Obj),
355 "Unusual: Returning alloca value", &I);
359 // TODO: Check that the reference is in bounds.
360 // TODO: Check readnone/readonly function attributes.
361 void Lint::visitMemoryReference(Instruction &I,
362 Value *Ptr, unsigned Size, unsigned Align,
363 const Type *Ty, unsigned Flags) {
364 // If no memory is being referenced, it doesn't matter if the pointer
369 Value *UnderlyingObject = findValue(Ptr, /*OffsetOk=*/true);
370 Assert1(!isa<ConstantPointerNull>(UnderlyingObject),
371 "Undefined behavior: Null pointer dereference", &I);
372 Assert1(!isa<UndefValue>(UnderlyingObject),
373 "Undefined behavior: Undef pointer dereference", &I);
374 Assert1(!isa<ConstantInt>(UnderlyingObject) ||
375 !cast<ConstantInt>(UnderlyingObject)->isAllOnesValue(),
376 "Unusual: All-ones pointer dereference", &I);
377 Assert1(!isa<ConstantInt>(UnderlyingObject) ||
378 !cast<ConstantInt>(UnderlyingObject)->isOne(),
379 "Unusual: Address one pointer dereference", &I);
381 if (Flags & MemRef::Write) {
382 if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(UnderlyingObject))
383 Assert1(!GV->isConstant(),
384 "Undefined behavior: Write to read-only memory", &I);
385 Assert1(!isa<Function>(UnderlyingObject) &&
386 !isa<BlockAddress>(UnderlyingObject),
387 "Undefined behavior: Write to text section", &I);
389 if (Flags & MemRef::Read) {
390 Assert1(!isa<Function>(UnderlyingObject),
391 "Unusual: Load from function body", &I);
392 Assert1(!isa<BlockAddress>(UnderlyingObject),
393 "Undefined behavior: Load from block address", &I);
395 if (Flags & MemRef::Callee) {
396 Assert1(!isa<BlockAddress>(UnderlyingObject),
397 "Undefined behavior: Call to block address", &I);
399 if (Flags & MemRef::Branchee) {
400 Assert1(!isa<Constant>(UnderlyingObject) ||
401 isa<BlockAddress>(UnderlyingObject),
402 "Undefined behavior: Branch to non-blockaddress", &I);
406 if (Align == 0 && Ty) Align = TD->getABITypeAlignment(Ty);
409 unsigned BitWidth = TD->getTypeSizeInBits(Ptr->getType());
410 APInt Mask = APInt::getAllOnesValue(BitWidth),
411 KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
412 ComputeMaskedBits(Ptr, Mask, KnownZero, KnownOne, TD);
413 Assert1(!(KnownOne & APInt::getLowBitsSet(BitWidth, Log2_32(Align))),
414 "Undefined behavior: Memory reference address is misaligned", &I);
419 void Lint::visitLoadInst(LoadInst &I) {
420 visitMemoryReference(I, I.getPointerOperand(),
421 AA->getTypeStoreSize(I.getType()), I.getAlignment(),
422 I.getType(), MemRef::Read);
425 void Lint::visitStoreInst(StoreInst &I) {
426 visitMemoryReference(I, I.getPointerOperand(),
427 AA->getTypeStoreSize(I.getOperand(0)->getType()),
429 I.getOperand(0)->getType(), MemRef::Write);
432 void Lint::visitXor(BinaryOperator &I) {
433 Assert1(!isa<UndefValue>(I.getOperand(0)) ||
434 !isa<UndefValue>(I.getOperand(1)),
435 "Undefined result: xor(undef, undef)", &I);
438 void Lint::visitSub(BinaryOperator &I) {
439 Assert1(!isa<UndefValue>(I.getOperand(0)) ||
440 !isa<UndefValue>(I.getOperand(1)),
441 "Undefined result: sub(undef, undef)", &I);
444 void Lint::visitLShr(BinaryOperator &I) {
445 if (ConstantInt *CI =
446 dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
447 Assert1(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
448 "Undefined result: Shift count out of range", &I);
451 void Lint::visitAShr(BinaryOperator &I) {
452 if (ConstantInt *CI =
453 dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
454 Assert1(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
455 "Undefined result: Shift count out of range", &I);
458 void Lint::visitShl(BinaryOperator &I) {
459 if (ConstantInt *CI =
460 dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
461 Assert1(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
462 "Undefined result: Shift count out of range", &I);
465 static bool isZero(Value *V, TargetData *TD) {
466 // Assume undef could be zero.
467 if (isa<UndefValue>(V)) return true;
469 unsigned BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
470 APInt Mask = APInt::getAllOnesValue(BitWidth),
471 KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
472 ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD);
473 return KnownZero.isAllOnesValue();
476 void Lint::visitSDiv(BinaryOperator &I) {
477 Assert1(!isZero(I.getOperand(1), TD),
478 "Undefined behavior: Division by zero", &I);
481 void Lint::visitUDiv(BinaryOperator &I) {
482 Assert1(!isZero(I.getOperand(1), TD),
483 "Undefined behavior: Division by zero", &I);
486 void Lint::visitSRem(BinaryOperator &I) {
487 Assert1(!isZero(I.getOperand(1), TD),
488 "Undefined behavior: Division by zero", &I);
491 void Lint::visitURem(BinaryOperator &I) {
492 Assert1(!isZero(I.getOperand(1), TD),
493 "Undefined behavior: Division by zero", &I);
496 void Lint::visitAllocaInst(AllocaInst &I) {
497 if (isa<ConstantInt>(I.getArraySize()))
498 // This isn't undefined behavior, it's just an obvious pessimization.
499 Assert1(&I.getParent()->getParent()->getEntryBlock() == I.getParent(),
500 "Pessimization: Static alloca outside of entry block", &I);
502 // TODO: Check for an unusual size (MSB set?)
505 void Lint::visitVAArgInst(VAArgInst &I) {
506 visitMemoryReference(I, I.getOperand(0), AliasAnalysis::UnknownSize, 0, 0,
507 MemRef::Read | MemRef::Write);
510 void Lint::visitIndirectBrInst(IndirectBrInst &I) {
511 visitMemoryReference(I, I.getAddress(), AliasAnalysis::UnknownSize, 0, 0,
514 Assert1(I.getNumDestinations() != 0,
515 "Undefined behavior: indirectbr with no destinations", &I);
518 void Lint::visitExtractElementInst(ExtractElementInst &I) {
519 if (ConstantInt *CI =
520 dyn_cast<ConstantInt>(findValue(I.getIndexOperand(),
521 /*OffsetOk=*/false)))
522 Assert1(CI->getValue().ult(I.getVectorOperandType()->getNumElements()),
523 "Undefined result: extractelement index out of range", &I);
526 void Lint::visitInsertElementInst(InsertElementInst &I) {
527 if (ConstantInt *CI =
528 dyn_cast<ConstantInt>(findValue(I.getOperand(2),
529 /*OffsetOk=*/false)))
530 Assert1(CI->getValue().ult(I.getType()->getNumElements()),
531 "Undefined result: insertelement index out of range", &I);
534 void Lint::visitUnreachableInst(UnreachableInst &I) {
535 // This isn't undefined behavior, it's merely suspicious.
536 Assert1(&I == I.getParent()->begin() ||
537 prior(BasicBlock::iterator(&I))->mayHaveSideEffects(),
538 "Unusual: unreachable immediately preceded by instruction without "
542 /// findValue - Look through bitcasts and simple memory reference patterns
543 /// to identify an equivalent, but more informative, value. If OffsetOk
544 /// is true, look through getelementptrs with non-zero offsets too.
546 /// Most analysis passes don't require this logic, because instcombine
547 /// will simplify most of these kinds of things away. But it's a goal of
548 /// this Lint pass to be useful even on non-optimized IR.
549 Value *Lint::findValue(Value *V, bool OffsetOk) const {
550 SmallPtrSet<Value *, 4> Visited;
551 return findValueImpl(V, OffsetOk, Visited);
554 /// findValueImpl - Implementation helper for findValue.
555 Value *Lint::findValueImpl(Value *V, bool OffsetOk,
556 SmallPtrSet<Value *, 4> &Visited) const {
557 // Detect self-referential values.
558 if (!Visited.insert(V))
559 return UndefValue::get(V->getType());
561 // TODO: Look through sext or zext cast, when the result is known to
562 // be interpreted as signed or unsigned, respectively.
563 // TODO: Look through eliminable cast pairs.
564 // TODO: Look through calls with unique return values.
565 // TODO: Look through vector insert/extract/shuffle.
566 V = OffsetOk ? V->getUnderlyingObject() : V->stripPointerCasts();
567 if (LoadInst *L = dyn_cast<LoadInst>(V)) {
568 BasicBlock::iterator BBI = L;
569 BasicBlock *BB = L->getParent();
570 SmallPtrSet<BasicBlock *, 4> VisitedBlocks;
572 if (!VisitedBlocks.insert(BB)) break;
573 if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(),
575 return findValueImpl(U, OffsetOk, Visited);
576 if (BBI != BB->begin()) break;
577 BB = BB->getUniquePredecessor();
581 } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
582 if (Value *W = PN->hasConstantValue(DT))
583 return findValueImpl(W, OffsetOk, Visited);
584 } else if (CastInst *CI = dyn_cast<CastInst>(V)) {
585 if (CI->isNoopCast(TD ? TD->getIntPtrType(V->getContext()) :
586 Type::getInt64Ty(V->getContext())))
587 return findValueImpl(CI->getOperand(0), OffsetOk, Visited);
588 } else if (ExtractValueInst *Ex = dyn_cast<ExtractValueInst>(V)) {
589 if (Value *W = FindInsertedValue(Ex->getAggregateOperand(),
593 return findValueImpl(W, OffsetOk, Visited);
594 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
595 // Same as above, but for ConstantExpr instead of Instruction.
596 if (Instruction::isCast(CE->getOpcode())) {
597 if (CastInst::isNoopCast(Instruction::CastOps(CE->getOpcode()),
598 CE->getOperand(0)->getType(),
600 TD ? TD->getIntPtrType(V->getContext()) :
601 Type::getInt64Ty(V->getContext())))
602 return findValueImpl(CE->getOperand(0), OffsetOk, Visited);
603 } else if (CE->getOpcode() == Instruction::ExtractValue) {
604 const SmallVector<unsigned, 4> &Indices = CE->getIndices();
605 if (Value *W = FindInsertedValue(CE->getOperand(0),
609 return findValueImpl(W, OffsetOk, Visited);
613 // As a last resort, try SimplifyInstruction or constant folding.
614 if (Instruction *Inst = dyn_cast<Instruction>(V)) {
615 if (Value *W = SimplifyInstruction(Inst, TD))
617 return findValueImpl(W, OffsetOk, Visited);
618 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
619 if (Value *W = ConstantFoldConstantExpression(CE, TD))
621 return findValueImpl(W, OffsetOk, Visited);
627 //===----------------------------------------------------------------------===//
628 // Implement the public interfaces to this file...
629 //===----------------------------------------------------------------------===//
631 FunctionPass *llvm::createLintPass() {
635 /// lintFunction - Check a function for errors, printing messages on stderr.
637 void llvm::lintFunction(const Function &f) {
638 Function &F = const_cast<Function&>(f);
639 assert(!F.isDeclaration() && "Cannot lint external functions");
641 FunctionPassManager FPM(F.getParent());
642 Lint *V = new Lint();
647 /// lintModule - Check a module for errors, printing messages on stderr.
649 void llvm::lintModule(const Module &M) {
651 Lint *V = new Lint();
653 PM.run(const_cast<Module&>(M));