#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LegacyPassManager.h"
void visitInsertElementInst(InsertElementInst &I);
void visitUnreachableInst(UnreachableInst &I);
- Value *findValue(Value *V, const DataLayout &DL, bool OffsetOk) const;
- Value *findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
+ Value *findValue(Value *V, bool OffsetOk) const;
+ Value *findValueImpl(Value *V, bool OffsetOk,
SmallPtrSetImpl<Value *> &Visited) const;
public:
Module *Mod;
+ const DataLayout *DL;
AliasAnalysis *AA;
AssumptionCache *AC;
DominatorTree *DT;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
- AU.addRequired<AliasAnalysis>();
+ AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
AU.addRequired<DominatorTreeWrapperPass>();
WriteValues({V1, Vs...});
}
};
-} // namespace
+}
char Lint::ID = 0;
INITIALIZE_PASS_BEGIN(Lint, "lint", "Statically lint-checks LLVM IR",
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
INITIALIZE_PASS_END(Lint, "lint", "Statically lint-checks LLVM IR",
false, true)
//
bool Lint::runOnFunction(Function &F) {
Mod = F.getParent();
- AA = &getAnalysis<AliasAnalysis>();
+ DL = &F.getParent()->getDataLayout();
+ AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
void Lint::visitCallSite(CallSite CS) {
Instruction &I = *CS.getInstruction();
Value *Callee = CS.getCalledValue();
- const DataLayout &DL = CS->getModule()->getDataLayout();
visitMemoryReference(I, Callee, MemoryLocation::UnknownSize, 0, nullptr,
MemRef::Callee);
- if (Function *F = dyn_cast<Function>(findValue(Callee, DL,
+ if (Function *F = dyn_cast<Function>(findValue(Callee,
/*OffsetOk=*/false))) {
Assert(CS.getCallingConv() == F->getCallingConv(),
"Undefined behavior: Caller and callee calling convention differ",
for (; AI != AE; ++AI) {
Value *Actual = *AI;
if (PI != PE) {
- Argument *Formal = PI++;
+ Argument *Formal = &*PI++;
Assert(Formal->getType() == Actual->getType(),
"Undefined behavior: Call argument type mismatches "
"callee parameter type",
if (Formal->hasStructRetAttr() && Actual->getType()->isPointerTy()) {
Type *Ty =
cast<PointerType>(Formal->getType())->getElementType();
- visitMemoryReference(I, Actual, AA->getTypeStoreSize(Ty),
- DL.getABITypeAlignment(Ty), Ty,
+ visitMemoryReference(I, Actual, DL->getTypeStoreSize(Ty),
+ DL->getABITypeAlignment(Ty), Ty,
MemRef::Read | MemRef::Write);
}
}
if (CS.isCall() && cast<CallInst>(CS.getInstruction())->isTailCall())
for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
AI != AE; ++AI) {
- Value *Obj = findValue(*AI, DL, /*OffsetOk=*/true);
+ Value *Obj = findValue(*AI, /*OffsetOk=*/true);
Assert(!isa<AllocaInst>(Obj),
"Undefined behavior: Call with \"tail\" keyword references "
"alloca",
// overlap is not distinguished from the case where nothing is known.
uint64_t Size = 0;
if (const ConstantInt *Len =
- dyn_cast<ConstantInt>(findValue(MCI->getLength(), DL,
+ dyn_cast<ConstantInt>(findValue(MCI->getLength(),
/*OffsetOk=*/false)))
if (Len->getValue().isIntN(32))
Size = Len->getValue().getZExtValue();
visitMemoryReference(I, CS.getArgument(0), MemoryLocation::UnknownSize, 0,
nullptr, MemRef::Read | MemRef::Write);
break;
-
- case Intrinsic::eh_begincatch:
- visitEHBeginCatch(II);
- break;
- case Intrinsic::eh_endcatch:
- visitEHEndCatch(II);
- break;
}
}
"Unusual: Return statement in function with noreturn attribute", &I);
if (Value *V = I.getReturnValue()) {
- Value *Obj =
- findValue(V, F->getParent()->getDataLayout(), /*OffsetOk=*/true);
+ Value *Obj = findValue(V, /*OffsetOk=*/true);
Assert(!isa<AllocaInst>(Obj), "Unusual: Returning alloca value", &I);
}
}
if (Size == 0)
return;
- Value *UnderlyingObject =
- findValue(Ptr, I.getModule()->getDataLayout(), /*OffsetOk=*/true);
+ Value *UnderlyingObject = findValue(Ptr, /*OffsetOk=*/true);
Assert(!isa<ConstantPointerNull>(UnderlyingObject),
"Undefined behavior: Null pointer dereference", &I);
Assert(!isa<UndefValue>(UnderlyingObject),
// Check for buffer overflows and misalignment.
// Only handles memory references that read/write something simple like an
// alloca instruction or a global variable.
- auto &DL = I.getModule()->getDataLayout();
int64_t Offset = 0;
- if (Value *Base = GetPointerBaseWithConstantOffset(Ptr, Offset, DL)) {
+ if (Value *Base = GetPointerBaseWithConstantOffset(Ptr, Offset, *DL)) {
// OK, so the access is to a constant offset from Ptr. Check that Ptr is
// something we can handle and if so extract the size of this base object
// along with its alignment.
if (AllocaInst *AI = dyn_cast<AllocaInst>(Base)) {
Type *ATy = AI->getAllocatedType();
if (!AI->isArrayAllocation() && ATy->isSized())
- BaseSize = DL.getTypeAllocSize(ATy);
+ BaseSize = DL->getTypeAllocSize(ATy);
BaseAlign = AI->getAlignment();
if (BaseAlign == 0 && ATy->isSized())
- BaseAlign = DL.getABITypeAlignment(ATy);
+ BaseAlign = DL->getABITypeAlignment(ATy);
} else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Base)) {
// If the global may be defined differently in another compilation unit
// then don't warn about funky memory accesses.
if (GV->hasDefinitiveInitializer()) {
Type *GTy = GV->getType()->getElementType();
if (GTy->isSized())
- BaseSize = DL.getTypeAllocSize(GTy);
+ BaseSize = DL->getTypeAllocSize(GTy);
BaseAlign = GV->getAlignment();
if (BaseAlign == 0 && GTy->isSized())
- BaseAlign = DL.getABITypeAlignment(GTy);
+ BaseAlign = DL->getABITypeAlignment(GTy);
}
}
// Accesses that say that the memory is more aligned than it is are not
// defined.
if (Align == 0 && Ty && Ty->isSized())
- Align = DL.getABITypeAlignment(Ty);
+ Align = DL->getABITypeAlignment(Ty);
Assert(!BaseAlign || Align <= MinAlign(BaseAlign, Offset),
"Undefined behavior: Memory reference address is misaligned", &I);
}
void Lint::visitLoadInst(LoadInst &I) {
visitMemoryReference(I, I.getPointerOperand(),
- AA->getTypeStoreSize(I.getType()), I.getAlignment(),
+ DL->getTypeStoreSize(I.getType()), I.getAlignment(),
I.getType(), MemRef::Read);
}
void Lint::visitStoreInst(StoreInst &I) {
visitMemoryReference(I, I.getPointerOperand(),
- AA->getTypeStoreSize(I.getOperand(0)->getType()),
+ DL->getTypeStoreSize(I.getOperand(0)->getType()),
I.getAlignment(),
I.getOperand(0)->getType(), MemRef::Write);
}
}
void Lint::visitLShr(BinaryOperator &I) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(
- findValue(I.getOperand(1), I.getModule()->getDataLayout(),
- /*OffsetOk=*/false)))
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(I.getOperand(1),
+ /*OffsetOk=*/false)))
Assert(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
"Undefined result: Shift count out of range", &I);
}
void Lint::visitAShr(BinaryOperator &I) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(
- I.getOperand(1), I.getModule()->getDataLayout(), /*OffsetOk=*/false)))
+ if (ConstantInt *CI =
+ dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
Assert(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
"Undefined result: Shift count out of range", &I);
}
void Lint::visitShl(BinaryOperator &I) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(
- I.getOperand(1), I.getModule()->getDataLayout(), /*OffsetOk=*/false)))
+ if (ConstantInt *CI =
+ dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
Assert(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
"Undefined result: Shift count out of range", &I);
}
-static bool
-allPredsCameFromLandingPad(BasicBlock *BB,
- SmallSet<BasicBlock *, 4> &VisitedBlocks) {
- VisitedBlocks.insert(BB);
- if (BB->isLandingPad())
- return true;
- // If we find a block with no predecessors, the search failed.
- if (pred_empty(BB))
- return false;
- for (BasicBlock *Pred : predecessors(BB)) {
- if (VisitedBlocks.count(Pred))
- continue;
- if (!allPredsCameFromLandingPad(Pred, VisitedBlocks))
- return false;
- }
- return true;
-}
-
-static bool
-allSuccessorsReachEndCatch(BasicBlock *BB, BasicBlock::iterator InstBegin,
- IntrinsicInst **SecondBeginCatch,
- SmallSet<BasicBlock *, 4> &VisitedBlocks) {
- VisitedBlocks.insert(BB);
- for (BasicBlock::iterator I = InstBegin, E = BB->end(); I != E; ++I) {
- IntrinsicInst *IC = dyn_cast<IntrinsicInst>(I);
- if (IC && IC->getIntrinsicID() == Intrinsic::eh_endcatch)
- return true;
- // If we find another begincatch while looking for an endcatch,
- // that's also an error.
- if (IC && IC->getIntrinsicID() == Intrinsic::eh_begincatch) {
- *SecondBeginCatch = IC;
- return false;
- }
- }
-
- // If we reach a block with no successors while searching, the
- // search has failed.
- if (succ_empty(BB))
- return false;
- // Otherwise, search all of the successors.
- for (BasicBlock *Succ : successors(BB)) {
- if (VisitedBlocks.count(Succ))
- continue;
- if (!allSuccessorsReachEndCatch(Succ, Succ->begin(), SecondBeginCatch,
- VisitedBlocks))
- return false;
- }
- return true;
-}
-
-void Lint::visitEHBeginCatch(IntrinsicInst *II) {
- // The checks in this function make a potentially dubious assumption about
- // the CFG, namely that any block involved in a catch is only used for the
- // catch. This will very likely be true of IR generated by a front end,
- // but it may cease to be true, for example, if the IR is run through a
- // pass which combines similar blocks.
- //
- // In general, if we encounter a block the isn't dominated by the catch
- // block while we are searching the catch block's successors for a call
- // to end catch intrinsic, then it is possible that it will be legal for
- // a path through this block to never reach a call to llvm.eh.endcatch.
- // An analogous statement could be made about our search for a landing
- // pad among the catch block's predecessors.
- //
- // What is actually required is that no path is possible at runtime that
- // reaches a call to llvm.eh.begincatch without having previously visited
- // a landingpad instruction and that no path is possible at runtime that
- // calls llvm.eh.begincatch and does not subsequently call llvm.eh.endcatch
- // (mentally adjusting for the fact that in reality these calls will be
- // removed before code generation).
- //
- // Because this is a lint check, we take a pessimistic approach and warn if
- // the control flow is potentially incorrect.
-
- SmallSet<BasicBlock *, 4> VisitedBlocks;
- BasicBlock *CatchBB = II->getParent();
-
- // The begin catch must occur in a landing pad block or all paths
- // to it must have come from a landing pad.
- Assert(allPredsCameFromLandingPad(CatchBB, VisitedBlocks),
- "llvm.eh.begincatch may be reachable without passing a landingpad",
- II);
-
- // Reset the visited block list.
- VisitedBlocks.clear();
-
- IntrinsicInst *SecondBeginCatch = nullptr;
-
- // This has to be called before it is asserted. Otherwise, the first assert
- // below can never be hit.
- bool EndCatchFound = allSuccessorsReachEndCatch(
- CatchBB, std::next(static_cast<BasicBlock::iterator>(II)),
- &SecondBeginCatch, VisitedBlocks);
- Assert(
- SecondBeginCatch == nullptr,
- "llvm.eh.begincatch may be called a second time before llvm.eh.endcatch",
- II, SecondBeginCatch);
- Assert(EndCatchFound,
- "Some paths from llvm.eh.begincatch may not reach llvm.eh.endcatch",
- II);
-}
-
-static bool allPredCameFromBeginCatch(
- BasicBlock *BB, BasicBlock::reverse_iterator InstRbegin,
- IntrinsicInst **SecondEndCatch, SmallSet<BasicBlock *, 4> &VisitedBlocks) {
- VisitedBlocks.insert(BB);
- // Look for a begincatch in this block.
- for (BasicBlock::reverse_iterator RI = InstRbegin, RE = BB->rend(); RI != RE;
- ++RI) {
- IntrinsicInst *IC = dyn_cast<IntrinsicInst>(&*RI);
- if (IC && IC->getIntrinsicID() == Intrinsic::eh_begincatch)
- return true;
- // If we find another end catch before we find a begin catch, that's
- // an error.
- if (IC && IC->getIntrinsicID() == Intrinsic::eh_endcatch) {
- *SecondEndCatch = IC;
- return false;
- }
- // If we encounter a landingpad instruction, the search failed.
- if (isa<LandingPadInst>(*RI))
- return false;
- }
- // If while searching we find a block with no predeccesors,
- // the search failed.
- if (pred_empty(BB))
- return false;
- // Search any predecessors we haven't seen before.
- for (BasicBlock *Pred : predecessors(BB)) {
- if (VisitedBlocks.count(Pred))
- continue;
- if (!allPredCameFromBeginCatch(Pred, Pred->rbegin(), SecondEndCatch,
- VisitedBlocks))
- return false;
- }
- return true;
-}
-
-void Lint::visitEHEndCatch(IntrinsicInst *II) {
- // The check in this function makes a potentially dubious assumption about
- // the CFG, namely that any block involved in a catch is only used for the
- // catch. This will very likely be true of IR generated by a front end,
- // but it may cease to be true, for example, if the IR is run through a
- // pass which combines similar blocks.
- //
- // In general, if we encounter a block the isn't post-dominated by the
- // end catch block while we are searching the end catch block's predecessors
- // for a call to the begin catch intrinsic, then it is possible that it will
- // be legal for a path to reach the end catch block without ever having
- // called llvm.eh.begincatch.
- //
- // What is actually required is that no path is possible at runtime that
- // reaches a call to llvm.eh.endcatch without having previously visited
- // a call to llvm.eh.begincatch (mentally adjusting for the fact that in
- // reality these calls will be removed before code generation).
- //
- // Because this is a lint check, we take a pessimistic approach and warn if
- // the control flow is potentially incorrect.
-
- BasicBlock *EndCatchBB = II->getParent();
-
- // Alls paths to the end catch call must pass through a begin catch call.
-
- // If llvm.eh.begincatch wasn't called in the current block, we'll use this
- // lambda to recursively look for it in predecessors.
- SmallSet<BasicBlock *, 4> VisitedBlocks;
- IntrinsicInst *SecondEndCatch = nullptr;
-
- // This has to be called before it is asserted. Otherwise, the first assert
- // below can never be hit.
- bool BeginCatchFound =
- allPredCameFromBeginCatch(EndCatchBB, BasicBlock::reverse_iterator(II),
- &SecondEndCatch, VisitedBlocks);
- Assert(
- SecondEndCatch == nullptr,
- "llvm.eh.endcatch may be called a second time after llvm.eh.begincatch",
- II, SecondEndCatch);
- Assert(BeginCatchFound,
- "llvm.eh.endcatch may be reachable without passing llvm.eh.begincatch",
- II);
-}
-
static bool isZero(Value *V, const DataLayout &DL, DominatorTree *DT,
AssumptionCache *AC) {
// Assume undef could be zero.
}
void Lint::visitExtractElementInst(ExtractElementInst &I) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(
- findValue(I.getIndexOperand(), I.getModule()->getDataLayout(),
- /*OffsetOk=*/false)))
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(I.getIndexOperand(),
+ /*OffsetOk=*/false)))
Assert(CI->getValue().ult(I.getVectorOperandType()->getNumElements()),
"Undefined result: extractelement index out of range", &I);
}
void Lint::visitInsertElementInst(InsertElementInst &I) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(
- findValue(I.getOperand(2), I.getModule()->getDataLayout(),
- /*OffsetOk=*/false)))
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(I.getOperand(2),
+ /*OffsetOk=*/false)))
Assert(CI->getValue().ult(I.getType()->getNumElements()),
"Undefined result: insertelement index out of range", &I);
}
void Lint::visitUnreachableInst(UnreachableInst &I) {
// This isn't undefined behavior, it's merely suspicious.
- Assert(&I == I.getParent()->begin() ||
- std::prev(BasicBlock::iterator(&I))->mayHaveSideEffects(),
+ Assert(&I == &I.getParent()->front() ||
+ std::prev(I.getIterator())->mayHaveSideEffects(),
"Unusual: unreachable immediately preceded by instruction without "
"side effects",
&I);
/// Most analysis passes don't require this logic, because instcombine
/// will simplify most of these kinds of things away. But it's a goal of
/// this Lint pass to be useful even on non-optimized IR.
-Value *Lint::findValue(Value *V, const DataLayout &DL, bool OffsetOk) const {
+Value *Lint::findValue(Value *V, bool OffsetOk) const {
SmallPtrSet<Value *, 4> Visited;
- return findValueImpl(V, DL, OffsetOk, Visited);
+ return findValueImpl(V, OffsetOk, Visited);
}
/// findValueImpl - Implementation helper for findValue.
-Value *Lint::findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
+Value *Lint::findValueImpl(Value *V, bool OffsetOk,
SmallPtrSetImpl<Value *> &Visited) const {
// Detect self-referential values.
if (!Visited.insert(V).second)
// TODO: Look through eliminable cast pairs.
// TODO: Look through calls with unique return values.
// TODO: Look through vector insert/extract/shuffle.
- V = OffsetOk ? GetUnderlyingObject(V, DL) : V->stripPointerCasts();
+ V = OffsetOk ? GetUnderlyingObject(V, *DL) : V->stripPointerCasts();
if (LoadInst *L = dyn_cast<LoadInst>(V)) {
- BasicBlock::iterator BBI = L;
+ BasicBlock::iterator BBI = L->getIterator();
BasicBlock *BB = L->getParent();
SmallPtrSet<BasicBlock *, 4> VisitedBlocks;
for (;;) {
if (!VisitedBlocks.insert(BB).second)
break;
- if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(),
- BB, BBI, 6, AA))
- return findValueImpl(U, DL, OffsetOk, Visited);
+ if (Value *U =
+ FindAvailableLoadedValue(L->getPointerOperand(),
+ BB, BBI, DefMaxInstsToScan, AA))
+ return findValueImpl(U, OffsetOk, Visited);
if (BBI != BB->begin()) break;
BB = BB->getUniquePredecessor();
if (!BB) break;
} else if (PHINode *PN = dyn_cast<PHINode>(V)) {
if (Value *W = PN->hasConstantValue())
if (W != V)
- return findValueImpl(W, DL, OffsetOk, Visited);
+ return findValueImpl(W, OffsetOk, Visited);
} else if (CastInst *CI = dyn_cast<CastInst>(V)) {
- if (CI->isNoopCast(DL))
- return findValueImpl(CI->getOperand(0), DL, OffsetOk, Visited);
+ if (CI->isNoopCast(*DL))
+ return findValueImpl(CI->getOperand(0), OffsetOk, Visited);
} else if (ExtractValueInst *Ex = dyn_cast<ExtractValueInst>(V)) {
if (Value *W = FindInsertedValue(Ex->getAggregateOperand(),
Ex->getIndices()))
if (W != V)
- return findValueImpl(W, DL, OffsetOk, Visited);
+ return findValueImpl(W, OffsetOk, Visited);
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
// Same as above, but for ConstantExpr instead of Instruction.
if (Instruction::isCast(CE->getOpcode())) {
if (CastInst::isNoopCast(Instruction::CastOps(CE->getOpcode()),
CE->getOperand(0)->getType(), CE->getType(),
- DL.getIntPtrType(V->getType())))
- return findValueImpl(CE->getOperand(0), DL, OffsetOk, Visited);
+ DL->getIntPtrType(V->getType())))
+ return findValueImpl(CE->getOperand(0), OffsetOk, Visited);
} else if (CE->getOpcode() == Instruction::ExtractValue) {
ArrayRef<unsigned> Indices = CE->getIndices();
if (Value *W = FindInsertedValue(CE->getOperand(0), Indices))
if (W != V)
- return findValueImpl(W, DL, OffsetOk, Visited);
+ return findValueImpl(W, OffsetOk, Visited);
}
}
// As a last resort, try SimplifyInstruction or constant folding.
if (Instruction *Inst = dyn_cast<Instruction>(V)) {
- if (Value *W = SimplifyInstruction(Inst, DL, TLI, DT, AC))
- return findValueImpl(W, DL, OffsetOk, Visited);
+ if (Value *W = SimplifyInstruction(Inst, *DL, TLI, DT, AC))
+ return findValueImpl(W, OffsetOk, Visited);
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
- if (Value *W = ConstantFoldConstantExpression(CE, DL, TLI))
+ if (Value *W = ConstantFoldConstantExpression(CE, *DL, TLI))
if (W != V)
- return findValueImpl(W, DL, OffsetOk, Visited);
+ return findValueImpl(W, OffsetOk, Visited);
}
return V;
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