ValueMapper.cpp revision 1bb95911de8d0821aff16bf0cb1e1dfe43856bf1 
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/Metadata.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/Support/ErrorHandling.h"
22using namespace llvm;
23
24Value *llvm::MapValue(const Value *V, ValueMapTy &VM) {
25  Value *&VMSlot = VM[V];
26  if (VMSlot) return VMSlot;      // Does it exist in the map yet?
27
28  // NOTE: VMSlot can be invalidated by any reference to VM, which can grow the
29  // DenseMap.  This includes any recursive calls to MapValue.
30
31  // Global values and metadata do not need to be seeded into the ValueMap if
32  // they are using the identity mapping.
33  if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MetadataBase>(V))
34    return VMSlot = const_cast<Value*>(V);
35
36  Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
37  if (C == 0) return 0;
38
39  if (isa<ConstantInt>(C) || isa<ConstantFP>(C) ||
40      isa<ConstantPointerNull>(C) || isa<ConstantAggregateZero>(C) ||
41      isa<UndefValue>(C) || isa<MDString>(C))
42    return VMSlot = C;           // Primitive constants map directly
43
44  if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
45    for (User::op_iterator b = CA->op_begin(), i = b, e = CA->op_end();
46         i != e; ++i) {
47      Value *MV = MapValue(*i, VM);
48      if (MV != *i) {
49        // This array must contain a reference to a global, make a new array
50        // and return it.
51        //
52        std::vector<Constant*> Values;
53        Values.reserve(CA->getNumOperands());
54        for (User::op_iterator j = b; j != i; ++j)
55          Values.push_back(cast<Constant>(*j));
56        Values.push_back(cast<Constant>(MV));
57        for (++i; i != e; ++i)
58          Values.push_back(cast<Constant>(MapValue(*i, VM)));
59        return VM[V] = ConstantArray::get(CA->getType(), Values);
60      }
61    }
62    return VM[V] = C;
63  }
64
65  if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
66    for (User::op_iterator b = CS->op_begin(), i = b, e = CS->op_end();
67         i != e; ++i) {
68      Value *MV = MapValue(*i, VM);
69      if (MV != *i) {
70        // This struct must contain a reference to a global, make a new struct
71        // and return it.
72        //
73        std::vector<Constant*> Values;
74        Values.reserve(CS->getNumOperands());
75        for (User::op_iterator j = b; j != i; ++j)
76          Values.push_back(cast<Constant>(*j));
77        Values.push_back(cast<Constant>(MV));
78        for (++i; i != e; ++i)
79          Values.push_back(cast<Constant>(MapValue(*i, VM)));
80        return VM[V] = ConstantStruct::get(CS->getType(), Values);
81      }
82    }
83    return VM[V] = C;
84  }
85
86  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
87    std::vector<Constant*> Ops;
88    for (User::op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i)
89      Ops.push_back(cast<Constant>(MapValue(*i, VM)));
90    return VM[V] = CE->getWithOperands(Ops);
91  }
92
93  if (ConstantVector *CV = dyn_cast<ConstantVector>(C)) {
94    for (User::op_iterator b = CV->op_begin(), i = b, e = CV->op_end();
95         i != e; ++i) {
96      Value *MV = MapValue(*i, VM);
97      if (MV != *i) {
98        // This vector value must contain a reference to a global, make a new
99        // vector constant and return it.
100        //
101        std::vector<Constant*> Values;
102        Values.reserve(CV->getNumOperands());
103        for (User::op_iterator j = b; j != i; ++j)
104          Values.push_back(cast<Constant>(*j));
105        Values.push_back(cast<Constant>(MV));
106        for (++i; i != e; ++i)
107          Values.push_back(cast<Constant>(MapValue(*i, VM)));
108        return VM[V] = ConstantVector::get(Values);
109      }
110    }
111    return VM[V] = C;
112  }
113
114  if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
115    Function *F = cast<Function>(MapValue(BA->getFunction(), VM));
116    BasicBlock *BB = cast<BasicBlock>(MapValue(BA->getBasicBlock(), VM));
117    return VM[V] = BlockAddress::get(F, BB);
118  }
119
120  llvm_unreachable("Unknown type of constant!");
121  return 0;
122}
123
124/// RemapInstruction - Convert the instruction operands from referencing the
125/// current values into those specified by ValueMap.
126///
127void llvm::RemapInstruction(Instruction *I, ValueMapTy &ValueMap) {
128  for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
129    Value *V = MapValue(*op, ValueMap);
130    assert(V && "Referenced value not in value map!");
131    *op = V;
132  }
133}
134