ValueMapper.cpp revision f58c34d5315a35d489c5c203ae45430ccb53f973 
1//===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// 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 "llvm/Transforms/Utils/ValueMapper.h"
16#include "llvm/DerivedTypes.h"  // For getNullValue(Type::Int32Ty)
17#include "llvm/Constants.h"
18#include "llvm/Function.h"
19#include "llvm/IntrinsicInst.h"
20#include "llvm/Metadata.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/Support/ErrorHandling.h"
23using namespace llvm;
24
25Value *llvm::MapValue(const Value *V, ValueMapTy &VM) {
26  Value *&VMSlot = VM[V];
27  if (VMSlot) return VMSlot;      // Does it exist in the map yet?
28
29  // NOTE: VMSlot can be invalidated by any reference to VM, which can grow the
30  // DenseMap.  This includes any recursive calls to MapValue.
31
32  // Global values and non-function-local metadata do not need to be seeded into
33  // the ValueMap if they are using the identity mapping.
34  if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MDString>(V) ||
35      (isa<MDNode>(V) && !dyn_cast<MDNode>(V)->isFunctionLocal()))
36    return VMSlot = const_cast<Value*>(V);
37
38  if (isa<MDNode>(V)) {
39    const MDNode *MD = dyn_cast<MDNode>(V);
40    std::vector<Value*> Elts;
41    Elts.reserve(MD->getNumOperands());
42    for (unsigned i = 0; i != MD->getNumOperands(); i++)
43      Elts.push_back(MapValue(MD->getOperand(i), VM));
44    return VM[V] = MDNode::get(V->getContext(), Elts.data(), Elts.size());
45  }
46
47  Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
48  if (C == 0) return 0;
49
50  if (isa<ConstantInt>(C) || isa<ConstantFP>(C) ||
51      isa<ConstantPointerNull>(C) || isa<ConstantAggregateZero>(C) ||
52      isa<UndefValue>(C) || isa<MDString>(C))
53    return VMSlot = C;           // Primitive constants map directly
54
55  if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
56    for (User::op_iterator b = CA->op_begin(), i = b, e = CA->op_end();
57         i != e; ++i) {
58      Value *MV = MapValue(*i, VM);
59      if (MV != *i) {
60        // This array must contain a reference to a global, make a new array
61        // and return it.
62        //
63        std::vector<Constant*> Values;
64        Values.reserve(CA->getNumOperands());
65        for (User::op_iterator j = b; j != i; ++j)
66          Values.push_back(cast<Constant>(*j));
67        Values.push_back(cast<Constant>(MV));
68        for (++i; i != e; ++i)
69          Values.push_back(cast<Constant>(MapValue(*i, VM)));
70        return VM[V] = ConstantArray::get(CA->getType(), Values);
71      }
72    }
73    return VM[V] = C;
74  }
75
76  if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
77    for (User::op_iterator b = CS->op_begin(), i = b, e = CS->op_end();
78         i != e; ++i) {
79      Value *MV = MapValue(*i, VM);
80      if (MV != *i) {
81        // This struct must contain a reference to a global, make a new struct
82        // and return it.
83        //
84        std::vector<Constant*> Values;
85        Values.reserve(CS->getNumOperands());
86        for (User::op_iterator j = b; j != i; ++j)
87          Values.push_back(cast<Constant>(*j));
88        Values.push_back(cast<Constant>(MV));
89        for (++i; i != e; ++i)
90          Values.push_back(cast<Constant>(MapValue(*i, VM)));
91        return VM[V] = ConstantStruct::get(CS->getType(), Values);
92      }
93    }
94    return VM[V] = C;
95  }
96
97  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
98    std::vector<Constant*> Ops;
99    for (User::op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i)
100      Ops.push_back(cast<Constant>(MapValue(*i, VM)));
101    return VM[V] = CE->getWithOperands(Ops);
102  }
103
104  if (ConstantVector *CV = dyn_cast<ConstantVector>(C)) {
105    for (User::op_iterator b = CV->op_begin(), i = b, e = CV->op_end();
106         i != e; ++i) {
107      Value *MV = MapValue(*i, VM);
108      if (MV != *i) {
109        // This vector value must contain a reference to a global, make a new
110        // vector constant and return it.
111        //
112        std::vector<Constant*> Values;
113        Values.reserve(CV->getNumOperands());
114        for (User::op_iterator j = b; j != i; ++j)
115          Values.push_back(cast<Constant>(*j));
116        Values.push_back(cast<Constant>(MV));
117        for (++i; i != e; ++i)
118          Values.push_back(cast<Constant>(MapValue(*i, VM)));
119        return VM[V] = ConstantVector::get(Values);
120      }
121    }
122    return VM[V] = C;
123  }
124
125  if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
126    Function *F = cast<Function>(MapValue(BA->getFunction(), VM));
127    BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(),VM));
128    return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
129  }
130
131  llvm_unreachable("Unknown type of constant!");
132  return 0;
133}
134
135/// RemapInstruction - Convert the instruction operands from referencing the
136/// current values into those specified by ValueMap.
137///
138void llvm::RemapInstruction(Instruction *I, ValueMapTy &ValueMap) {
139  for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
140    Value *V = MapValue(*op, ValueMap);
141    assert(V && "Referenced value not in value map!");
142    *op = V;
143  }
144}
145
146