ValueMapper.cpp revision c6646ebdb957a3c613d389be8b0135271b8b8ece 
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/Instruction.h"
18using namespace llvm;
19
20Value *llvm::MapValue(const Value *V, std::map<const Value*, Value*> &VM) {
21  Value *&VMSlot = VM[V];
22  if (VMSlot) return VMSlot;      // Does it exist in the map yet?
23
24  // Global values do not need to be seeded into the ValueMap if they are using
25  // the identity mapping.
26  if (isa<GlobalValue>(V))
27    return VMSlot = const_cast<Value*>(V);
28
29  if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
30    if (isa<ConstantIntegral>(C) || isa<ConstantFP>(C) ||
31        isa<ConstantPointerNull>(C))
32      return VMSlot = C;           // Primitive constants map directly
33    else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)) {
34      GlobalValue *MV = cast<GlobalValue>(MapValue((Value*)CPR->getValue(),VM));
35      return VMSlot = ConstantPointerRef::get(MV);
36    } else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
37      const std::vector<Use> &Vals = CA->getValues();
38      for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
39        Value *MV = MapValue(Vals[i], VM);
40        if (MV != Vals[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(Vals.size());
46          for (unsigned j = 0; j != i; ++j)
47            Values.push_back(cast<Constant>(Vals[j]));
48          Values.push_back(cast<Constant>(MV));
49          for (++i; i != e; ++i)
50            Values.push_back(cast<Constant>(MapValue(Vals[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      const std::vector<Use> &Vals = CS->getValues();
58      for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
59        Value *MV = MapValue(Vals[i], VM);
60        if (MV != Vals[i]) {
61          // This struct must contain a reference to a global, make a new struct
62          // and return it.
63          //
64          std::vector<Constant*> Values;
65          Values.reserve(Vals.size());
66          for (unsigned j = 0; j != i; ++j)
67            Values.push_back(cast<Constant>(Vals[j]));
68          Values.push_back(cast<Constant>(MV));
69          for (++i; i != e; ++i)
70            Values.push_back(cast<Constant>(MapValue(Vals[i], VM)));
71          return VMSlot = ConstantStruct::get(CS->getType(), Values);
72        }
73      }
74      return VMSlot = C;
75
76    } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
77      if (CE->getOpcode() == Instruction::Cast) {
78        Constant *MV = cast<Constant>(MapValue(CE->getOperand(0), VM));
79        return VMSlot = ConstantExpr::getCast(MV, CE->getType());
80      } else if (CE->getOpcode() == Instruction::GetElementPtr) {
81        std::vector<Constant*> Idx;
82        Constant *MV = cast<Constant>(MapValue(CE->getOperand(0), VM));
83        for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
84          Idx.push_back(cast<Constant>(MapValue(CE->getOperand(i), VM)));
85        return VMSlot = ConstantExpr::getGetElementPtr(MV, Idx);
86      } else {
87        assert(CE->getNumOperands() == 2 && "Must be binary operator?");
88        Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
89        Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
90        return VMSlot = ConstantExpr::get(CE->getOpcode(), MV1, MV2);
91      }
92
93    } else {
94      assert(0 && "Unknown type of constant!");
95    }
96  }
97
98  V->dump();
99  assert(0 && "Unknown value type: why didn't it get resolved?!");
100  return 0;
101}
102