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"
23 class TargetLibraryInfo;
25 /// PHITransAddr - An address value which tracks and handles phi translation.
26 /// As we walk "up" the CFG through predecessors, we need to ensure that the
27 /// address we're tracking is kept up to date. For example, if we're analyzing
28 /// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
29 /// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
30 /// incorrect pointer in the predecessor block.
32 /// This is designed to be a relatively small object that lives on the stack and
36 /// Addr - The actual address we're analyzing.
39 /// TD - The target data we are playing with if known, otherwise null.
42 /// TLI - The target library info if known, otherwise null.
43 const TargetLibraryInfo *TLI;
45 /// InstInputs - The inputs for our symbolic address.
46 SmallVector<Instruction*, 4> InstInputs;
48 PHITransAddr(Value *addr, const DataLayout *td) : Addr(addr), TD(td), TLI(0) {
49 // If the address is an instruction, the whole thing is considered an input.
50 if (Instruction *I = dyn_cast<Instruction>(Addr))
51 InstInputs.push_back(I);
54 Value *getAddr() const { return Addr; }
56 /// NeedsPHITranslationFromBlock - Return true if moving from the specified
57 /// BasicBlock to its predecessors requires PHI translation.
58 bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
59 // We do need translation if one of our input instructions is defined in
61 for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
62 if (InstInputs[i]->getParent() == BB)
67 /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
68 /// if we have some hope of doing it. This should be used as a filter to
69 /// avoid calling PHITranslateValue in hopeless situations.
70 bool IsPotentiallyPHITranslatable() const;
72 /// PHITranslateValue - PHI translate the current address up the CFG from
73 /// CurBB to Pred, updating our state to reflect any needed changes. If the
74 /// dominator tree DT is non-null, the translated value must dominate
75 /// PredBB. This returns true on failure and sets Addr to null.
76 bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB,
77 const DominatorTree *DT);
79 /// PHITranslateWithInsertion - PHI translate this value into the specified
80 /// predecessor block, inserting a computation of the value if it is
83 /// All newly created instructions are added to the NewInsts list. This
84 /// returns null on failure.
86 Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
87 const DominatorTree &DT,
88 SmallVectorImpl<Instruction*> &NewInsts);
92 /// Verify - Check internal consistency of this data structure. If the
93 /// structure is valid, it returns true. If invalid, it prints errors and
97 Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB,
98 const DominatorTree *DT);
100 /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
101 /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
102 /// block. All newly created instructions are added to the NewInsts list.
103 /// This returns null on failure.
105 Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
106 BasicBlock *PredBB, const DominatorTree &DT,
107 SmallVectorImpl<Instruction*> &NewInsts);
109 /// AddAsInput - If the specified value is an instruction, add it as an input.
110 Value *AddAsInput(Value *V) {
111 // If V is an instruction, it is now an input.
112 if (Instruction *VI = dyn_cast<Instruction>(V))
113 InstInputs.push_back(VI);
119 } // end namespace llvm