ValueMapper.cpp revision 82731c793a9fbe53d8c5e784e3638cd3ad09d5ca 
1//===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the MapValue function, which is shared by various parts of
11// the lib/Transforms/Utils library.
12//
13//===----------------------------------------------------------------------===//
14
15#include "ValueMapper.h"
16#include "llvm/Constants.h"
17#include "llvm/GlobalValue.h"
18#include "llvm/Instruction.h"
19#include <iostream>
20
21using namespace llvm;
22
23Value *llvm::MapValue(const Value *V, std::map<const Value*, Value*> &VM) {
24  Value *&VMSlot = VM[V];
25  if (VMSlot) return VMSlot;      // Does it exist in the map yet?
26
27  // Global values do not need to be seeded into the ValueMap if they are using
28  // the identity mapping.
29  if (isa<GlobalValue>(V))
30    return VMSlot = const_cast<Value*>(V);
31
32  if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
33    if (isa<ConstantIntegral>(C) || isa<ConstantFP>(C) ||
34        isa<ConstantPointerNull>(C) || isa<ConstantAggregateZero>(C) ||
35        isa<UndefValue>(C))
36      return VMSlot = C;           // Primitive constants map directly
37    else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
38      for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
39        Value *MV = MapValue(CA->getOperand(i), VM);
40        if (MV != CA->getOperand(i)) {
41          // This array must contain a reference to a global, make a new array
42          // and return it.
43          //
44          std::vector<Constant*> Values;
45          Values.reserve(CA->getNumOperands());
46          for (unsigned j = 0; j != i; ++j)
47            Values.push_back(CA->getOperand(j));
48          Values.push_back(cast<Constant>(MV));
49          for (++i; i != e; ++i)
50            Values.push_back(cast<Constant>(MapValue(CA->getOperand(i), VM)));
51          return VMSlot = ConstantArray::get(CA->getType(), Values);
52        }
53      }
54      return VMSlot = C;
55
56    } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
57      for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
58        Value *MV = MapValue(CS->getOperand(i), VM);
59        if (MV != CS->getOperand(i)) {
60          // This struct must contain a reference to a global, make a new struct
61          // and return it.
62          //
63          std::vector<Constant*> Values;
64          Values.reserve(CS->getNumOperands());
65          for (unsigned j = 0; j != i; ++j)
66            Values.push_back(CS->getOperand(j));
67          Values.push_back(cast<Constant>(MV));
68          for (++i; i != e; ++i)
69            Values.push_back(cast<Constant>(MapValue(CS->getOperand(i), VM)));
70          return VMSlot = ConstantStruct::get(CS->getType(), Values);
71        }
72      }
73      return VMSlot = C;
74
75    } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
76      if (CE->getOpcode() == Instruction::Cast) {
77        Constant *MV = cast<Constant>(MapValue(CE->getOperand(0), VM));
78        return VMSlot = ConstantExpr::getCast(MV, CE->getType());
79      } else if (CE->getOpcode() == Instruction::GetElementPtr) {
80        std::vector<Constant*> Idx;
81        Constant *MV = cast<Constant>(MapValue(CE->getOperand(0), VM));
82        for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
83          Idx.push_back(cast<Constant>(MapValue(CE->getOperand(i), VM)));
84        return VMSlot = ConstantExpr::getGetElementPtr(MV, Idx);
85      } else if (CE->getOpcode() == Instruction::Select) {
86        Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
87        Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
88        Constant *MV3 = cast<Constant>(MapValue(CE->getOperand(2), VM));
89        return VMSlot = ConstantExpr::getSelect(MV1, MV2, MV3);
90      } else {
91        assert(CE->getNumOperands() == 2 && "Must be binary operator?");
92        Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
93        Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
94        return VMSlot = ConstantExpr::get(CE->getOpcode(), MV1, MV2);
95      }
96
97    } else {
98      assert(0 && "Unknown type of constant!");
99    }
100  }
101
102  V->dump();
103  assert(0 && "Unknown value type: why didn't it get resolved?!");
104  return 0;
105}
106
107/// RemapInstruction - Convert the instruction operands from referencing the
108/// current values into those specified by ValueMap.
109///
110void llvm::RemapInstruction(Instruction *I,
111                            std::map<const Value *, Value*> &ValueMap) {
112  for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
113    const Value *Op = I->getOperand(op);
114    Value *V = MapValue(Op, ValueMap);
115#ifndef NDEBUG
116    if (!V) {
117      std::cerr << "Val = \n" << *Op << "Addr = " << (void*)Op;
118      std::cerr << "\nInst = " << *I;
119    }
120#endif
121    assert(V && "Referenced value not in value map!");
122    I->setOperand(op, V);
123  }
124}
125