aboutsummaryrefslogtreecommitdiff
path: root/lib/Transforms/Utils/ValueMapper.cpp
blob: a30b09321b5e6e5e0f364d46770fd883fa07d67d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
//===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MapValue function, which is shared by various parts of
// the lib/Transforms/Utils library.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/ValueMapper.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Metadata.h"
using namespace llvm;

// Out of line method to get vtable etc for class.
void ValueMapTypeRemapper::anchor() {}

Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
                      ValueMapTypeRemapper *TypeMapper) {
  ValueToValueMapTy::iterator I = VM.find(V);
  
  // If the value already exists in the map, use it.
  if (I != VM.end() && I->second) return I->second;
  
  // Global values do not need to be seeded into the VM if they
  // are using the identity mapping.
  if (isa<GlobalValue>(V) || isa<MDString>(V))
    return VM[V] = const_cast<Value*>(V);
  
  if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
    // Inline asm may need *type* remapping.
    FunctionType *NewTy = IA->getFunctionType();
    if (TypeMapper) {
      NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));

      if (NewTy != IA->getFunctionType())
        V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
                           IA->hasSideEffects(), IA->isAlignStack());
    }
    
    return VM[V] = const_cast<Value*>(V);
  }
  

  if (const MDNode *MD = dyn_cast<MDNode>(V)) {
    // If this is a module-level metadata and we know that nothing at the module
    // level is changing, then use an identity mapping.
    if (!MD->isFunctionLocal() && (Flags & RF_NoModuleLevelChanges))
      return VM[V] = const_cast<Value*>(V);
    
    // Create a dummy node in case we have a metadata cycle.
    MDNode *Dummy = MDNode::getTemporary(V->getContext(), ArrayRef<Value*>());
    VM[V] = Dummy;
    
    // Check all operands to see if any need to be remapped.
    for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
      Value *OP = MD->getOperand(i);
      if (OP == 0 || MapValue(OP, VM, Flags, TypeMapper) == OP) continue;

      // Ok, at least one operand needs remapping.  
      SmallVector<Value*, 4> Elts;
      Elts.reserve(MD->getNumOperands());
      for (i = 0; i != e; ++i) {
        Value *Op = MD->getOperand(i);
        Elts.push_back(Op ? MapValue(Op, VM, Flags, TypeMapper) : 0);
      }
      MDNode *NewMD = MDNode::get(V->getContext(), Elts);
      Dummy->replaceAllUsesWith(NewMD);
      VM[V] = NewMD;
      MDNode::deleteTemporary(Dummy);
      return NewMD;
    }

    VM[V] = const_cast<Value*>(V);
    MDNode::deleteTemporary(Dummy);

    // No operands needed remapping.  Use an identity mapping.
    return const_cast<Value*>(V);
  }

  // Okay, this either must be a constant (which may or may not be mappable) or
  // is something that is not in the mapping table.
  Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
  if (C == 0)
    return 0;
  
  if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
    Function *F = 
      cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper));
    BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
                                                       Flags, TypeMapper));
    return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
  }
  
  // Otherwise, we have some other constant to remap.  Start by checking to see
  // if all operands have an identity remapping.
  unsigned OpNo = 0, NumOperands = C->getNumOperands();
  Value *Mapped = 0;
  for (; OpNo != NumOperands; ++OpNo) {
    Value *Op = C->getOperand(OpNo);
    Mapped = MapValue(Op, VM, Flags, TypeMapper);
    if (Mapped != C) break;
  }
  
  // See if the type mapper wants to remap the type as well.
  Type *NewTy = C->getType();
  if (TypeMapper)
    NewTy = TypeMapper->remapType(NewTy);

  // If the result type and all operands match up, then just insert an identity
  // mapping.
  if (OpNo == NumOperands && NewTy == C->getType())
    return VM[V] = C;
  
  // Okay, we need to create a new constant.  We've already processed some or
  // all of the operands, set them all up now.
  SmallVector<Constant*, 8> Ops;
  Ops.reserve(NumOperands);
  for (unsigned j = 0; j != OpNo; ++j)
    Ops.push_back(cast<Constant>(C->getOperand(j)));
  
  // If one of the operands mismatch, push it and the other mapped operands.
  if (OpNo != NumOperands) {
    Ops.push_back(cast<Constant>(Mapped));
  
    // Map the rest of the operands that aren't processed yet.
    for (++OpNo; OpNo != NumOperands; ++OpNo)
      Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
                             Flags, TypeMapper));
  }
  
  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
    return VM[V] = CE->getWithOperands(Ops, NewTy);
  if (isa<ConstantArray>(C))
    return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
  if (isa<ConstantStruct>(C))
    return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
  if (isa<ConstantVector>(C))
    return VM[V] = ConstantVector::get(Ops);
  // If this is a no-operand constant, it must be because the type was remapped.
  if (isa<UndefValue>(C))
    return VM[V] = UndefValue::get(NewTy);
  if (isa<ConstantAggregateZero>(C))
    return VM[V] = ConstantAggregateZero::get(NewTy);
  assert(isa<ConstantPointerNull>(C));
  return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
}

/// RemapInstruction - Convert the instruction operands from referencing the
/// current values into those specified by VMap.
///
void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
                            RemapFlags Flags, ValueMapTypeRemapper *TypeMapper){
  // Remap operands.
  for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
    Value *V = MapValue(*op, VMap, Flags, TypeMapper);
    // If we aren't ignoring missing entries, assert that something happened.
    if (V != 0)
      *op = V;
    else
      assert((Flags & RF_IgnoreMissingEntries) &&
             "Referenced value not in value map!");
  }

  // Remap phi nodes' incoming blocks.
  if (PHINode *PN = dyn_cast<PHINode>(I)) {
    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
      Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
      // If we aren't ignoring missing entries, assert that something happened.
      if (V != 0)
        PN->setIncomingBlock(i, cast<BasicBlock>(V));
      else
        assert((Flags & RF_IgnoreMissingEntries) &&
               "Referenced block not in value map!");
    }
  }

  // Remap attached metadata.
  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
  I->getAllMetadata(MDs);
  for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
       MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI) {
    MDNode *Old = MI->second;
    MDNode *New = MapValue(Old, VMap, Flags, TypeMapper);
    if (New != Old)
      I->setMetadata(MI->first, New);
  }
  
  // If the instruction's type is being remapped, do so now.
  if (TypeMapper)
    I->mutateType(TypeMapper->remapType(I->getType()));
}