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Diffstat (limited to 'include/llvm/Analysis/PointerTracking.h')
-rw-r--r-- | include/llvm/Analysis/PointerTracking.h | 132 |
1 files changed, 0 insertions, 132 deletions
diff --git a/include/llvm/Analysis/PointerTracking.h b/include/llvm/Analysis/PointerTracking.h deleted file mode 100644 index 6b49e18..0000000 --- a/include/llvm/Analysis/PointerTracking.h +++ /dev/null @@ -1,132 +0,0 @@ -//===- PointerTracking.h - Pointer Bounds Tracking --------------*- C++ -*-===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements tracking of pointer bounds. -// It knows that the libc functions "calloc" and "realloc" allocate memory, thus -// you should avoid using this pass if they mean something else for your -// language. -// -// All methods assume that the pointer is not NULL, if it is then the returned -// allocation size is wrong, and the result from checkLimits is wrong too. -// It also assumes that pointers are valid, and that it is not analyzing a -// use-after-free scenario. -// Due to these limitations the "size" returned by these methods should be -// considered as either 0 or the returned size. -// -// Another analysis pass should be used to find use-after-free/NULL dereference -// bugs. -// -//===----------------------------------------------------------------------===// - -#ifndef LLVM_ANALYSIS_POINTERTRACKING_H -#define LLVM_ANALYSIS_POINTERTRACKING_H - -#include "llvm/ADT/SmallPtrSet.h" -#include "llvm/Analysis/Dominators.h" -#include "llvm/Instructions.h" -#include "llvm/Pass.h" -#include "llvm/Support/PredIteratorCache.h" - -namespace llvm { - class DominatorTree; - class ScalarEvolution; - class SCEV; - class Loop; - class LoopInfo; - class TargetData; - - // Result from solver, assuming pointer is not NULL, - // and it is not a use-after-free situation. - enum SolverResult { - AlwaysFalse,// always false with above constraints - AlwaysTrue,// always true with above constraints - Unknown // it can sometimes be true, sometimes false, or it is undecided - }; - - class PointerTracking : public FunctionPass { - public: - typedef ICmpInst::Predicate Predicate; - static char ID; - PointerTracking(); - - virtual bool doInitialization(Module &M); - - // If this pointer directly points to an allocation, return - // the number of elements of type Ty allocated. - // Otherwise return CouldNotCompute. - // Since allocations can fail by returning NULL, the real element count - // for every allocation is either 0 or the value returned by this function. - const SCEV *getAllocationElementCount(Value *P) const; - - // Same as getAllocationSize() but returns size in bytes. - // We consider one byte as 8 bits. - const SCEV *getAllocationSizeInBytes(Value *V) const; - - // Given a Pointer, determine a base pointer of known size, and an offset - // therefrom. - // When unable to determine, sets Base to NULL, and Limit/Offset to - // CouldNotCompute. - // BaseSize, and Offset are in bytes: Pointer == Base + Offset - void getPointerOffset(Value *Pointer, Value *&Base, const SCEV *& BaseSize, - const SCEV *&Offset) const; - - // Compares the 2 scalar evolution expressions according to predicate, - // and if it can prove that the result is always true or always false - // return AlwaysTrue/AlwaysFalse. Otherwise it returns Unknown. - enum SolverResult compareSCEV(const SCEV *A, Predicate Pred, const SCEV *B, - const Loop *L); - - // Determines whether the condition LHS <Pred> RHS is sufficient - // for the condition A <Pred> B to hold. - // Currently only ULT/ULE is supported. - // This errs on the side of returning false. - bool conditionSufficient(const SCEV *LHS, Predicate Pred1, const SCEV *RHS, - const SCEV *A, Predicate Pred2, const SCEV *B, - const Loop *L); - - // Determines whether Offset is known to be always in [0, Limit) bounds. - // This errs on the side of returning Unknown. - enum SolverResult checkLimits(const SCEV *Offset, const SCEV *Limit, - BasicBlock *BB); - - virtual bool runOnFunction(Function &F); - virtual void getAnalysisUsage(AnalysisUsage &AU) const; - void print(raw_ostream &OS, const Module* = 0) const; - Value *computeAllocationCountValue(Value *P, const Type *&Ty) const; - private: - Function *FF; - TargetData *TD; - ScalarEvolution *SE; - LoopInfo *LI; - DominatorTree *DT; - - Function *callocFunc; - Function *reallocFunc; - PredIteratorCache predCache; - - SmallPtrSet<const SCEV*, 1> analyzing; - - enum SolverResult isLoopGuardedBy(const Loop *L, Predicate Pred, - const SCEV *A, const SCEV *B) const; - static bool isMonotonic(const SCEV *S); - bool scevPositive(const SCEV *A, const Loop *L, bool strict=true) const; - bool conditionSufficient(Value *Cond, bool negated, - const SCEV *A, Predicate Pred, const SCEV *B); - Value *getConditionToReach(BasicBlock *A, - DomTreeNodeBase<BasicBlock> *B, - bool &negated); - Value *getConditionToReach(BasicBlock *A, - BasicBlock *B, - bool &negated); - const SCEV *computeAllocationCount(Value *P, const Type *&Ty) const; - const SCEV *computeAllocationCountForType(Value *P, const Type *Ty) const; - }; -} -#endif - |