663 lines
25 KiB
C++
663 lines
25 KiB
C++
//===-- Lint.cpp - Check for common errors in LLVM IR ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass statically checks for common and easily-identified constructs
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// which produce undefined or likely unintended behavior in LLVM IR.
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//
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// It is not a guarantee of correctness, in two ways. First, it isn't
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// comprehensive. There are checks which could be done statically which are
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// not yet implemented. Some of these are indicated by TODO comments, but
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// those aren't comprehensive either. Second, many conditions cannot be
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// checked statically. This pass does no dynamic instrumentation, so it
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// can't check for all possible problems.
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//
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// Another limitation is that it assumes all code will be executed. A store
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// through a null pointer in a basic block which is never reached is harmless,
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// but this pass will warn about it anyway. This is the main reason why most
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// of these checks live here instead of in the Verifier pass.
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//
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// Optimization passes may make conditions that this pass checks for more or
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// less obvious. If an optimization pass appears to be introducing a warning,
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// it may be that the optimization pass is merely exposing an existing
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// condition in the code.
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//
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// This code may be run before instcombine. In many cases, instcombine checks
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// for the same kinds of things and turns instructions with undefined behavior
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// into unreachable (or equivalent). Because of this, this pass makes some
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// effort to look through bitcasts and so on.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/Passes.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/Analysis/ConstantFolding.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/Lint.h"
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#include "llvm/Analysis/Loads.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Pass.h"
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#include "llvm/PassManager.h"
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#include "llvm/IntrinsicInst.h"
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#include "llvm/Function.h"
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#include "llvm/Support/CallSite.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/InstVisitor.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/ADT/STLExtras.h"
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using namespace llvm;
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namespace {
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namespace MemRef {
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static unsigned Read = 1;
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static unsigned Write = 2;
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static unsigned Callee = 4;
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static unsigned Branchee = 8;
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}
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class Lint : public FunctionPass, public InstVisitor<Lint> {
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friend class InstVisitor<Lint>;
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void visitFunction(Function &F);
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void visitCallSite(CallSite CS);
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void visitMemoryReference(Instruction &I, Value *Ptr,
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unsigned Size, unsigned Align,
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const Type *Ty, unsigned Flags);
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void visitCallInst(CallInst &I);
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void visitInvokeInst(InvokeInst &I);
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void visitReturnInst(ReturnInst &I);
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void visitLoadInst(LoadInst &I);
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void visitStoreInst(StoreInst &I);
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void visitXor(BinaryOperator &I);
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void visitSub(BinaryOperator &I);
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void visitLShr(BinaryOperator &I);
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void visitAShr(BinaryOperator &I);
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void visitShl(BinaryOperator &I);
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void visitSDiv(BinaryOperator &I);
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void visitUDiv(BinaryOperator &I);
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void visitSRem(BinaryOperator &I);
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void visitURem(BinaryOperator &I);
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void visitAllocaInst(AllocaInst &I);
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void visitVAArgInst(VAArgInst &I);
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void visitIndirectBrInst(IndirectBrInst &I);
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void visitExtractElementInst(ExtractElementInst &I);
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void visitInsertElementInst(InsertElementInst &I);
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void visitUnreachableInst(UnreachableInst &I);
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Value *findValue(Value *V, bool OffsetOk) const;
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Value *findValueImpl(Value *V, bool OffsetOk,
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SmallPtrSet<Value *, 4> &Visited) const;
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public:
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Module *Mod;
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AliasAnalysis *AA;
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DominatorTree *DT;
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TargetData *TD;
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std::string Messages;
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raw_string_ostream MessagesStr;
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static char ID; // Pass identification, replacement for typeid
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Lint() : FunctionPass(ID), MessagesStr(Messages) {}
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virtual bool runOnFunction(Function &F);
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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AU.addRequired<AliasAnalysis>();
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AU.addRequired<DominatorTree>();
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}
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virtual void print(raw_ostream &O, const Module *M) const {}
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void WriteValue(const Value *V) {
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if (!V) return;
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if (isa<Instruction>(V)) {
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MessagesStr << *V << '\n';
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} else {
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WriteAsOperand(MessagesStr, V, true, Mod);
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MessagesStr << '\n';
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}
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}
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void WriteType(const Type *T) {
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if (!T) return;
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MessagesStr << ' ';
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WriteTypeSymbolic(MessagesStr, T, Mod);
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}
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// CheckFailed - A check failed, so print out the condition and the message
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// that failed. This provides a nice place to put a breakpoint if you want
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// to see why something is not correct.
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void CheckFailed(const Twine &Message,
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const Value *V1 = 0, const Value *V2 = 0,
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const Value *V3 = 0, const Value *V4 = 0) {
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MessagesStr << Message.str() << "\n";
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WriteValue(V1);
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WriteValue(V2);
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WriteValue(V3);
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WriteValue(V4);
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}
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void CheckFailed(const Twine &Message, const Value *V1,
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const Type *T2, const Value *V3 = 0) {
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MessagesStr << Message.str() << "\n";
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WriteValue(V1);
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WriteType(T2);
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WriteValue(V3);
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}
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void CheckFailed(const Twine &Message, const Type *T1,
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const Type *T2 = 0, const Type *T3 = 0) {
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MessagesStr << Message.str() << "\n";
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WriteType(T1);
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WriteType(T2);
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WriteType(T3);
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}
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};
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}
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char Lint::ID = 0;
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INITIALIZE_PASS(Lint, "lint", "Statically lint-checks LLVM IR", false, true);
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// Assert - We know that cond should be true, if not print an error message.
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#define Assert(C, M) \
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do { if (!(C)) { CheckFailed(M); return; } } while (0)
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#define Assert1(C, M, V1) \
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do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
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#define Assert2(C, M, V1, V2) \
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do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
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#define Assert3(C, M, V1, V2, V3) \
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do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
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#define Assert4(C, M, V1, V2, V3, V4) \
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do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
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// Lint::run - This is the main Analysis entry point for a
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// function.
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//
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bool Lint::runOnFunction(Function &F) {
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Mod = F.getParent();
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AA = &getAnalysis<AliasAnalysis>();
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DT = &getAnalysis<DominatorTree>();
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TD = getAnalysisIfAvailable<TargetData>();
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visit(F);
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dbgs() << MessagesStr.str();
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Messages.clear();
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return false;
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}
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void Lint::visitFunction(Function &F) {
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// This isn't undefined behavior, it's just a little unusual, and it's a
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// fairly common mistake to neglect to name a function.
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Assert1(F.hasName() || F.hasLocalLinkage(),
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"Unusual: Unnamed function with non-local linkage", &F);
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// TODO: Check for irreducible control flow.
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}
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void Lint::visitCallSite(CallSite CS) {
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Instruction &I = *CS.getInstruction();
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Value *Callee = CS.getCalledValue();
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visitMemoryReference(I, Callee, ~0u, 0, 0, MemRef::Callee);
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if (Function *F = dyn_cast<Function>(findValue(Callee, /*OffsetOk=*/false))) {
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Assert1(CS.getCallingConv() == F->getCallingConv(),
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"Undefined behavior: Caller and callee calling convention differ",
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&I);
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const FunctionType *FT = F->getFunctionType();
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unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
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Assert1(FT->isVarArg() ?
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FT->getNumParams() <= NumActualArgs :
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FT->getNumParams() == NumActualArgs,
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"Undefined behavior: Call argument count mismatches callee "
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"argument count", &I);
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Assert1(FT->getReturnType() == I.getType(),
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"Undefined behavior: Call return type mismatches "
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"callee return type", &I);
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// Check argument types (in case the callee was casted) and attributes.
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// TODO: Verify that caller and callee attributes are compatible.
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Function::arg_iterator PI = F->arg_begin(), PE = F->arg_end();
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CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
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for (; AI != AE; ++AI) {
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Value *Actual = *AI;
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if (PI != PE) {
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Argument *Formal = PI++;
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Assert1(Formal->getType() == Actual->getType(),
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"Undefined behavior: Call argument type mismatches "
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"callee parameter type", &I);
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// Check that noalias arguments don't alias other arguments. The
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// AliasAnalysis API isn't expressive enough for what we really want
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// to do. Known partial overlap is not distinguished from the case
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// where nothing is known.
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if (Formal->hasNoAliasAttr() && Actual->getType()->isPointerTy())
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for (CallSite::arg_iterator BI = CS.arg_begin(); BI != AE; ++BI) {
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Assert1(AI == BI || AA->alias(*AI, *BI) != AliasAnalysis::MustAlias,
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"Unusual: noalias argument aliases another argument", &I);
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}
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// Check that an sret argument points to valid memory.
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if (Formal->hasStructRetAttr() && Actual->getType()->isPointerTy()) {
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const Type *Ty =
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cast<PointerType>(Formal->getType())->getElementType();
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visitMemoryReference(I, Actual, AA->getTypeStoreSize(Ty),
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TD ? TD->getABITypeAlignment(Ty) : 0,
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Ty, MemRef::Read | MemRef::Write);
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}
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}
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}
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}
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if (CS.isCall() && cast<CallInst>(CS.getInstruction())->isTailCall())
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for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
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AI != AE; ++AI) {
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Value *Obj = findValue(*AI, /*OffsetOk=*/true);
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Assert1(!isa<AllocaInst>(Obj),
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"Undefined behavior: Call with \"tail\" keyword references "
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"alloca", &I);
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}
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if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I))
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switch (II->getIntrinsicID()) {
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default: break;
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// TODO: Check more intrinsics
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case Intrinsic::memcpy: {
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MemCpyInst *MCI = cast<MemCpyInst>(&I);
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// TODO: If the size is known, use it.
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visitMemoryReference(I, MCI->getDest(), ~0u, MCI->getAlignment(), 0,
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MemRef::Write);
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visitMemoryReference(I, MCI->getSource(), ~0u, MCI->getAlignment(), 0,
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MemRef::Read);
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// Check that the memcpy arguments don't overlap. The AliasAnalysis API
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// isn't expressive enough for what we really want to do. Known partial
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// overlap is not distinguished from the case where nothing is known.
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unsigned Size = 0;
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if (const ConstantInt *Len =
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dyn_cast<ConstantInt>(findValue(MCI->getLength(),
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/*OffsetOk=*/false)))
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if (Len->getValue().isIntN(32))
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Size = Len->getValue().getZExtValue();
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Assert1(AA->alias(MCI->getSource(), Size, MCI->getDest(), Size) !=
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AliasAnalysis::MustAlias,
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"Undefined behavior: memcpy source and destination overlap", &I);
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break;
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}
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case Intrinsic::memmove: {
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MemMoveInst *MMI = cast<MemMoveInst>(&I);
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// TODO: If the size is known, use it.
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visitMemoryReference(I, MMI->getDest(), ~0u, MMI->getAlignment(), 0,
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MemRef::Write);
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visitMemoryReference(I, MMI->getSource(), ~0u, MMI->getAlignment(), 0,
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MemRef::Read);
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break;
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}
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case Intrinsic::memset: {
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MemSetInst *MSI = cast<MemSetInst>(&I);
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// TODO: If the size is known, use it.
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visitMemoryReference(I, MSI->getDest(), ~0u, MSI->getAlignment(), 0,
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MemRef::Write);
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break;
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}
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case Intrinsic::vastart:
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Assert1(I.getParent()->getParent()->isVarArg(),
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"Undefined behavior: va_start called in a non-varargs function",
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&I);
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visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
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MemRef::Read | MemRef::Write);
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break;
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case Intrinsic::vacopy:
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visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0, MemRef::Write);
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visitMemoryReference(I, CS.getArgument(1), ~0u, 0, 0, MemRef::Read);
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break;
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case Intrinsic::vaend:
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visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
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MemRef::Read | MemRef::Write);
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break;
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case Intrinsic::stackrestore:
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// Stackrestore doesn't read or write memory, but it sets the
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// stack pointer, which the compiler may read from or write to
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// at any time, so check it for both readability and writeability.
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visitMemoryReference(I, CS.getArgument(0), ~0u, 0, 0,
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MemRef::Read | MemRef::Write);
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break;
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}
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}
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void Lint::visitCallInst(CallInst &I) {
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return visitCallSite(&I);
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}
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void Lint::visitInvokeInst(InvokeInst &I) {
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return visitCallSite(&I);
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}
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void Lint::visitReturnInst(ReturnInst &I) {
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Function *F = I.getParent()->getParent();
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Assert1(!F->doesNotReturn(),
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"Unusual: Return statement in function with noreturn attribute",
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&I);
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if (Value *V = I.getReturnValue()) {
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Value *Obj = findValue(V, /*OffsetOk=*/true);
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Assert1(!isa<AllocaInst>(Obj),
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"Unusual: Returning alloca value", &I);
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}
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}
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// TODO: Check that the reference is in bounds.
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// TODO: Check readnone/readonly function attributes.
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void Lint::visitMemoryReference(Instruction &I,
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Value *Ptr, unsigned Size, unsigned Align,
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const Type *Ty, unsigned Flags) {
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// If no memory is being referenced, it doesn't matter if the pointer
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// is valid.
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if (Size == 0)
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return;
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Value *UnderlyingObject = findValue(Ptr, /*OffsetOk=*/true);
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Assert1(!isa<ConstantPointerNull>(UnderlyingObject),
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"Undefined behavior: Null pointer dereference", &I);
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Assert1(!isa<UndefValue>(UnderlyingObject),
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"Undefined behavior: Undef pointer dereference", &I);
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Assert1(!isa<ConstantInt>(UnderlyingObject) ||
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!cast<ConstantInt>(UnderlyingObject)->isAllOnesValue(),
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"Unusual: All-ones pointer dereference", &I);
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Assert1(!isa<ConstantInt>(UnderlyingObject) ||
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!cast<ConstantInt>(UnderlyingObject)->isOne(),
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"Unusual: Address one pointer dereference", &I);
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if (Flags & MemRef::Write) {
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if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(UnderlyingObject))
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Assert1(!GV->isConstant(),
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"Undefined behavior: Write to read-only memory", &I);
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Assert1(!isa<Function>(UnderlyingObject) &&
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!isa<BlockAddress>(UnderlyingObject),
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"Undefined behavior: Write to text section", &I);
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}
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if (Flags & MemRef::Read) {
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Assert1(!isa<Function>(UnderlyingObject),
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"Unusual: Load from function body", &I);
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Assert1(!isa<BlockAddress>(UnderlyingObject),
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"Undefined behavior: Load from block address", &I);
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}
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if (Flags & MemRef::Callee) {
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Assert1(!isa<BlockAddress>(UnderlyingObject),
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"Undefined behavior: Call to block address", &I);
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}
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if (Flags & MemRef::Branchee) {
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Assert1(!isa<Constant>(UnderlyingObject) ||
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isa<BlockAddress>(UnderlyingObject),
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"Undefined behavior: Branch to non-blockaddress", &I);
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}
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if (TD) {
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if (Align == 0 && Ty) Align = TD->getABITypeAlignment(Ty);
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if (Align != 0) {
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unsigned BitWidth = TD->getTypeSizeInBits(Ptr->getType());
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APInt Mask = APInt::getAllOnesValue(BitWidth),
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KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
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ComputeMaskedBits(Ptr, Mask, KnownZero, KnownOne, TD);
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Assert1(!(KnownOne & APInt::getLowBitsSet(BitWidth, Log2_32(Align))),
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"Undefined behavior: Memory reference address is misaligned", &I);
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}
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}
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}
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void Lint::visitLoadInst(LoadInst &I) {
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visitMemoryReference(I, I.getPointerOperand(),
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AA->getTypeStoreSize(I.getType()), I.getAlignment(),
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I.getType(), MemRef::Read);
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}
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void Lint::visitStoreInst(StoreInst &I) {
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visitMemoryReference(I, I.getPointerOperand(),
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AA->getTypeStoreSize(I.getOperand(0)->getType()),
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I.getAlignment(),
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I.getOperand(0)->getType(), MemRef::Write);
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}
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void Lint::visitXor(BinaryOperator &I) {
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Assert1(!isa<UndefValue>(I.getOperand(0)) ||
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!isa<UndefValue>(I.getOperand(1)),
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"Undefined result: xor(undef, undef)", &I);
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}
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void Lint::visitSub(BinaryOperator &I) {
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Assert1(!isa<UndefValue>(I.getOperand(0)) ||
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!isa<UndefValue>(I.getOperand(1)),
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"Undefined result: sub(undef, undef)", &I);
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}
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void Lint::visitLShr(BinaryOperator &I) {
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if (ConstantInt *CI =
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dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
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Assert1(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
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"Undefined result: Shift count out of range", &I);
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}
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void Lint::visitAShr(BinaryOperator &I) {
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if (ConstantInt *CI =
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dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
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Assert1(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
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"Undefined result: Shift count out of range", &I);
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}
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void Lint::visitShl(BinaryOperator &I) {
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if (ConstantInt *CI =
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dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
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Assert1(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
|
|
"Undefined result: Shift count out of range", &I);
|
|
}
|
|
|
|
static bool isZero(Value *V, TargetData *TD) {
|
|
// Assume undef could be zero.
|
|
if (isa<UndefValue>(V)) return true;
|
|
|
|
unsigned BitWidth = cast<IntegerType>(V->getType())->getBitWidth();
|
|
APInt Mask = APInt::getAllOnesValue(BitWidth),
|
|
KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
|
|
ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD);
|
|
return KnownZero.isAllOnesValue();
|
|
}
|
|
|
|
void Lint::visitSDiv(BinaryOperator &I) {
|
|
Assert1(!isZero(I.getOperand(1), TD),
|
|
"Undefined behavior: Division by zero", &I);
|
|
}
|
|
|
|
void Lint::visitUDiv(BinaryOperator &I) {
|
|
Assert1(!isZero(I.getOperand(1), TD),
|
|
"Undefined behavior: Division by zero", &I);
|
|
}
|
|
|
|
void Lint::visitSRem(BinaryOperator &I) {
|
|
Assert1(!isZero(I.getOperand(1), TD),
|
|
"Undefined behavior: Division by zero", &I);
|
|
}
|
|
|
|
void Lint::visitURem(BinaryOperator &I) {
|
|
Assert1(!isZero(I.getOperand(1), TD),
|
|
"Undefined behavior: Division by zero", &I);
|
|
}
|
|
|
|
void Lint::visitAllocaInst(AllocaInst &I) {
|
|
if (isa<ConstantInt>(I.getArraySize()))
|
|
// This isn't undefined behavior, it's just an obvious pessimization.
|
|
Assert1(&I.getParent()->getParent()->getEntryBlock() == I.getParent(),
|
|
"Pessimization: Static alloca outside of entry block", &I);
|
|
|
|
// TODO: Check for an unusual size (MSB set?)
|
|
}
|
|
|
|
void Lint::visitVAArgInst(VAArgInst &I) {
|
|
visitMemoryReference(I, I.getOperand(0), ~0u, 0, 0,
|
|
MemRef::Read | MemRef::Write);
|
|
}
|
|
|
|
void Lint::visitIndirectBrInst(IndirectBrInst &I) {
|
|
visitMemoryReference(I, I.getAddress(), ~0u, 0, 0, MemRef::Branchee);
|
|
|
|
Assert1(I.getNumDestinations() != 0,
|
|
"Undefined behavior: indirectbr with no destinations", &I);
|
|
}
|
|
|
|
void Lint::visitExtractElementInst(ExtractElementInst &I) {
|
|
if (ConstantInt *CI =
|
|
dyn_cast<ConstantInt>(findValue(I.getIndexOperand(),
|
|
/*OffsetOk=*/false)))
|
|
Assert1(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),
|
|
/*OffsetOk=*/false)))
|
|
Assert1(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.
|
|
Assert1(&I == I.getParent()->begin() ||
|
|
prior(BasicBlock::iterator(&I))->mayHaveSideEffects(),
|
|
"Unusual: unreachable immediately preceded by instruction without "
|
|
"side effects", &I);
|
|
}
|
|
|
|
/// findValue - Look through bitcasts and simple memory reference patterns
|
|
/// to identify an equivalent, but more informative, value. If OffsetOk
|
|
/// is true, look through getelementptrs with non-zero offsets too.
|
|
///
|
|
/// 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, bool OffsetOk) const {
|
|
SmallPtrSet<Value *, 4> Visited;
|
|
return findValueImpl(V, OffsetOk, Visited);
|
|
}
|
|
|
|
/// findValueImpl - Implementation helper for findValue.
|
|
Value *Lint::findValueImpl(Value *V, bool OffsetOk,
|
|
SmallPtrSet<Value *, 4> &Visited) const {
|
|
// Detect self-referential values.
|
|
if (!Visited.insert(V))
|
|
return UndefValue::get(V->getType());
|
|
|
|
// TODO: Look through sext or zext cast, when the result is known to
|
|
// be interpreted as signed or unsigned, respectively.
|
|
// TODO: Look through eliminable cast pairs.
|
|
// TODO: Look through calls with unique return values.
|
|
// TODO: Look through vector insert/extract/shuffle.
|
|
V = OffsetOk ? V->getUnderlyingObject() : V->stripPointerCasts();
|
|
if (LoadInst *L = dyn_cast<LoadInst>(V)) {
|
|
BasicBlock::iterator BBI = L;
|
|
BasicBlock *BB = L->getParent();
|
|
SmallPtrSet<BasicBlock *, 4> VisitedBlocks;
|
|
for (;;) {
|
|
if (!VisitedBlocks.insert(BB)) break;
|
|
if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(),
|
|
BB, BBI, 6, AA))
|
|
return findValueImpl(U, OffsetOk, Visited);
|
|
if (BBI != BB->begin()) break;
|
|
BB = BB->getUniquePredecessor();
|
|
if (!BB) break;
|
|
BBI = BB->end();
|
|
}
|
|
} else if (PHINode *PN = dyn_cast<PHINode>(V)) {
|
|
if (Value *W = PN->hasConstantValue(DT))
|
|
return findValueImpl(W, OffsetOk, Visited);
|
|
} else if (CastInst *CI = dyn_cast<CastInst>(V)) {
|
|
if (CI->isNoopCast(TD ? TD->getIntPtrType(V->getContext()) :
|
|
Type::getInt64Ty(V->getContext())))
|
|
return findValueImpl(CI->getOperand(0), OffsetOk, Visited);
|
|
} else if (ExtractValueInst *Ex = dyn_cast<ExtractValueInst>(V)) {
|
|
if (Value *W = FindInsertedValue(Ex->getAggregateOperand(),
|
|
Ex->idx_begin(),
|
|
Ex->idx_end()))
|
|
if (W != V)
|
|
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(),
|
|
TD ? TD->getIntPtrType(V->getContext()) :
|
|
Type::getInt64Ty(V->getContext())))
|
|
return findValueImpl(CE->getOperand(0), OffsetOk, Visited);
|
|
} else if (CE->getOpcode() == Instruction::ExtractValue) {
|
|
const SmallVector<unsigned, 4> &Indices = CE->getIndices();
|
|
if (Value *W = FindInsertedValue(CE->getOperand(0),
|
|
Indices.begin(),
|
|
Indices.end()))
|
|
if (W != V)
|
|
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, TD))
|
|
if (W != Inst)
|
|
return findValueImpl(W, OffsetOk, Visited);
|
|
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
|
|
if (Value *W = ConstantFoldConstantExpression(CE, TD))
|
|
if (W != V)
|
|
return findValueImpl(W, OffsetOk, Visited);
|
|
}
|
|
|
|
return V;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Implement the public interfaces to this file...
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
FunctionPass *llvm::createLintPass() {
|
|
return new Lint();
|
|
}
|
|
|
|
/// lintFunction - Check a function for errors, printing messages on stderr.
|
|
///
|
|
void llvm::lintFunction(const Function &f) {
|
|
Function &F = const_cast<Function&>(f);
|
|
assert(!F.isDeclaration() && "Cannot lint external functions");
|
|
|
|
FunctionPassManager FPM(F.getParent());
|
|
Lint *V = new Lint();
|
|
FPM.add(V);
|
|
FPM.run(F);
|
|
}
|
|
|
|
/// lintModule - Check a module for errors, printing messages on stderr.
|
|
///
|
|
void llvm::lintModule(const Module &M) {
|
|
PassManager PM;
|
|
Lint *V = new Lint();
|
|
PM.add(V);
|
|
PM.run(const_cast<Module&>(M));
|
|
}
|