1 //===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===//
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 file declares the PHITransAddr class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_PHITRANSADDR_H
15 #define LLVM_ANALYSIS_PHITRANSADDR_H
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/IR/Instruction.h"
21 class AssumptionCache;
24 class TargetLibraryInfo;
26 /// PHITransAddr - An address value which tracks and handles phi translation.
27 /// As we walk "up" the CFG through predecessors, we need to ensure that the
28 /// address we're tracking is kept up to date. For example, if we're analyzing
29 /// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
30 /// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
31 /// incorrect pointer in the predecessor block.
33 /// This is designed to be a relatively small object that lives on the stack and
37 /// Addr - The actual address we're analyzing.
40 /// The DataLayout we are playing with.
43 /// TLI - The target library info if known, otherwise null.
44 const TargetLibraryInfo *TLI;
46 /// A cache of @llvm.assume calls used by SimplifyInstruction.
49 /// InstInputs - The inputs for our symbolic address.
50 SmallVector<Instruction*, 4> InstInputs;
52 PHITransAddr(Value *addr, const DataLayout &DL, AssumptionCache *AC)
53 : Addr(addr), DL(DL), TLI(nullptr), AC(AC) {
54 // If the address is an instruction, the whole thing is considered an input.
55 if (Instruction *I = dyn_cast<Instruction>(Addr))
56 InstInputs.push_back(I);
59 Value *getAddr() const { return Addr; }
61 /// NeedsPHITranslationFromBlock - Return true if moving from the specified
62 /// BasicBlock to its predecessors requires PHI translation.
63 bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
64 // We do need translation if one of our input instructions is defined in
66 for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
67 if (InstInputs[i]->getParent() == BB)
72 /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
73 /// if we have some hope of doing it. This should be used as a filter to
74 /// avoid calling PHITranslateValue in hopeless situations.
75 bool IsPotentiallyPHITranslatable() const;
77 /// PHITranslateValue - PHI translate the current address up the CFG from
78 /// CurBB to Pred, updating our state to reflect any needed changes. If
79 /// 'MustDominate' is true, the translated value must dominate
80 /// PredBB. This returns true on failure and sets Addr to null.
81 bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB,
82 const DominatorTree *DT, bool MustDominate);
84 /// PHITranslateWithInsertion - PHI translate this value into the specified
85 /// predecessor block, inserting a computation of the value if it is
88 /// All newly created instructions are added to the NewInsts list. This
89 /// returns null on failure.
91 Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
92 const DominatorTree &DT,
93 SmallVectorImpl<Instruction*> &NewInsts);
97 /// Verify - Check internal consistency of this data structure. If the
98 /// structure is valid, it returns true. If invalid, it prints errors and
102 Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB,
103 const DominatorTree *DT);
105 /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
106 /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
107 /// block. All newly created instructions are added to the NewInsts list.
108 /// This returns null on failure.
110 Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
111 BasicBlock *PredBB, const DominatorTree &DT,
112 SmallVectorImpl<Instruction*> &NewInsts);
114 /// AddAsInput - If the specified value is an instruction, add it as an input.
115 Value *AddAsInput(Value *V) {
116 // If V is an instruction, it is now an input.
117 if (Instruction *VI = dyn_cast<Instruction>(V))
118 InstInputs.push_back(VI);
124 } // end namespace llvm