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//===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the PHITransAddr class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_PHITRANSADDR_H
#define LLVM_ANALYSIS_PHITRANSADDR_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Instruction.h"
namespace llvm {
class AssumptionCache;
class DominatorTree;
class DataLayout;
class TargetLibraryInfo;
/// PHITransAddr - An address value which tracks and handles phi translation.
/// As we walk "up" the CFG through predecessors, we need to ensure that the
/// address we're tracking is kept up to date. For example, if we're analyzing
/// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
/// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
/// incorrect pointer in the predecessor block.
///
/// This is designed to be a relatively small object that lives on the stack and
/// is copyable.
///
class PHITransAddr {
/// Addr - The actual address we're analyzing.
Value *Addr;
/// The DataLayout we are playing with if known, otherwise null.
const DataLayout *DL;
/// TLI - The target library info if known, otherwise null.
const TargetLibraryInfo *TLI;
/// A cache of @llvm.assume calls used by SimplifyInstruction.
AssumptionCache *AC;
/// InstInputs - The inputs for our symbolic address.
SmallVector<Instruction*, 4> InstInputs;
public:
PHITransAddr(Value *addr, const DataLayout *DL, AssumptionCache *AC)
: Addr(addr), DL(DL), TLI(nullptr), AC(AC) {
// If the address is an instruction, the whole thing is considered an input.
if (Instruction *I = dyn_cast<Instruction>(Addr))
InstInputs.push_back(I);
}
Value *getAddr() const { return Addr; }
/// NeedsPHITranslationFromBlock - Return true if moving from the specified
/// BasicBlock to its predecessors requires PHI translation.
bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
// We do need translation if one of our input instructions is defined in
// this block.
for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
if (InstInputs[i]->getParent() == BB)
return true;
return false;
}
/// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
/// if we have some hope of doing it. This should be used as a filter to
/// avoid calling PHITranslateValue in hopeless situations.
bool IsPotentiallyPHITranslatable() const;
/// PHITranslateValue - PHI translate the current address up the CFG from
/// CurBB to Pred, updating our state to reflect any needed changes. If the
/// dominator tree DT is non-null, the translated value must dominate
/// PredBB. This returns true on failure and sets Addr to null.
bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB,
const DominatorTree *DT);
/// PHITranslateWithInsertion - PHI translate this value into the specified
/// predecessor block, inserting a computation of the value if it is
/// unavailable.
///
/// All newly created instructions are added to the NewInsts list. This
/// returns null on failure.
///
Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
const DominatorTree &DT,
SmallVectorImpl<Instruction*> &NewInsts);
void dump() const;
/// Verify - Check internal consistency of this data structure. If the
/// structure is valid, it returns true. If invalid, it prints errors and
/// returns false.
bool Verify() const;
private:
Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB,
const DominatorTree *DT);
/// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block. All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
BasicBlock *PredBB, const DominatorTree &DT,
SmallVectorImpl<Instruction*> &NewInsts);
/// AddAsInput - If the specified value is an instruction, add it as an input.
Value *AddAsInput(Value *V) {
// If V is an instruction, it is now an input.
if (Instruction *VI = dyn_cast<Instruction>(V))
InstInputs.push_back(VI);
return V;
}
};
} // end namespace llvm
#endif
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