ValueMapper.cpp revision e7a6663eb155eb8eb5de24cf22f632790485e5f9 
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"
18
19Value *MapValue(const Value *V, std::map<const Value*, Value*> &VM) {
20  Value *&VMSlot = VM[V];
21  if (VMSlot) return VMSlot;      // Does it exist in the map yet?
22
23  // Global values do not need to be seeded into the ValueMap if they are using
24  // the identity mapping.
25  if (isa<GlobalValue>(V))
26    return VMSlot = const_cast<Value*>(V);
27
28  if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
29    if (isa<ConstantIntegral>(C) || isa<ConstantFP>(C) ||
30        isa<ConstantPointerNull>(C))
31      return VMSlot = C;           // Primitive constants map directly
32    else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)) {
33      GlobalValue *MV = cast<GlobalValue>(MapValue((Value*)CPR->getValue(),VM));
34      return VMSlot = ConstantPointerRef::get(MV);
35    } else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
36      const std::vector<Use> &Vals = CA->getValues();
37      for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
38        Value *MV = MapValue(Vals[i], VM);
39        if (MV != Vals[i]) {
40          // This array must contain a reference to a global, make a new array
41          // and return it.
42          //
43          std::vector<Constant*> Values;
44          Values.reserve(Vals.size());
45          for (unsigned j = 0; j != i; ++j)
46            Values.push_back(cast<Constant>(Vals[j]));
47          Values.push_back(cast<Constant>(MV));
48          for (++i; i != e; ++i)
49            Values.push_back(cast<Constant>(MapValue(Vals[i], VM)));
50          return VMSlot = ConstantArray::get(CA->getType(), Values);
51        }
52      }
53      return VMSlot = C;
54
55    } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
56      const std::vector<Use> &Vals = CS->getValues();
57      for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
58        Value *MV = MapValue(Vals[i], VM);
59        if (MV != Vals[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(Vals.size());
65          for (unsigned j = 0; j != i; ++j)
66            Values.push_back(cast<Constant>(Vals[j]));
67          Values.push_back(cast<Constant>(MV));
68          for (++i; i != e; ++i)
69            Values.push_back(cast<Constant>(MapValue(Vals[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::Shl ||
86                 CE->getOpcode() == Instruction::Shr) {
87        assert(CE->getNumOperands() == 2 && "Must be a shift!");
88        Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
89        Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
90        return VMSlot = ConstantExpr::getShift(CE->getOpcode(), MV1, MV2);
91      } else {
92        assert(CE->getNumOperands() == 2 && "Must be binary operator?");
93        Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
94        Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
95        return VMSlot = ConstantExpr::get(CE->getOpcode(), MV1, MV2);
96      }
97
98    } else {
99      assert(0 && "Unknown type of constant!");
100    }
101  }
102
103  V->dump();
104  assert(0 && "Unknown value type: why didn't it get resolved?!");
105  return 0;
106}
107
108