1 //===- ValueMapper.h - Remapping for constants and metadata -----*- C++ -*-===//
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 interface which is used by various parts of
11 // the Transforms/Utils library to implement cloning and linking facilities.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_TRANSFORMS_UTILS_VALUEMAPPER_H
16 #define LLVM_TRANSFORMS_UTILS_VALUEMAPPER_H
17 
18 #include "llvm/IR/ValueMap.h"
19 
20 namespace llvm {
21   class Value;
22   class Instruction;
23   typedef ValueMap<const Value *, WeakVH> ValueToValueMapTy;
24 
25   /// ValueMapTypeRemapper - This is a class that can be implemented by clients
26   /// to remap types when cloning constants and instructions.
27   class ValueMapTypeRemapper {
28     virtual void anchor();  // Out of line method.
29   public:
~ValueMapTypeRemapper()30     virtual ~ValueMapTypeRemapper() {}
31 
32     /// remapType - The client should implement this method if they want to
33     /// remap types while mapping values.
34     virtual Type *remapType(Type *SrcTy) = 0;
35   };
36 
37   /// ValueMaterializer - This is a class that can be implemented by clients
38   /// to materialize Values on demand.
39   class ValueMaterializer {
40     virtual void anchor(); // Out of line method.
41   public:
~ValueMaterializer()42     virtual ~ValueMaterializer() {}
43 
44     /// materializeValueFor - The client should implement this method if they
45     /// want to generate a mapped Value on demand. For example, if linking
46     /// lazily.
47     virtual Value *materializeValueFor(Value *V) = 0;
48   };
49 
50   /// RemapFlags - These are flags that the value mapping APIs allow.
51   enum RemapFlags {
52     RF_None = 0,
53 
54     /// RF_NoModuleLevelChanges - If this flag is set, the remapper knows that
55     /// only local values within a function (such as an instruction or argument)
56     /// are mapped, not global values like functions and global metadata.
57     RF_NoModuleLevelChanges = 1,
58 
59     /// RF_IgnoreMissingEntries - If this flag is set, the remapper ignores
60     /// entries that are not in the value map.  If it is unset, it aborts if an
61     /// operand is asked to be remapped which doesn't exist in the mapping.
62     RF_IgnoreMissingEntries = 2
63   };
64 
65   static inline RemapFlags operator|(RemapFlags LHS, RemapFlags RHS) {
66     return RemapFlags(unsigned(LHS)|unsigned(RHS));
67   }
68 
69   Value *MapValue(const Value *V, ValueToValueMapTy &VM,
70                   RemapFlags Flags = RF_None,
71                   ValueMapTypeRemapper *TypeMapper = nullptr,
72                   ValueMaterializer *Materializer = nullptr);
73 
74   Metadata *MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
75                         RemapFlags Flags = RF_None,
76                         ValueMapTypeRemapper *TypeMapper = nullptr,
77                         ValueMaterializer *Materializer = nullptr);
78 
79   /// MapMetadata - provide versions that preserve type safety for MDNodes.
80   MDNode *MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
81                       RemapFlags Flags = RF_None,
82                       ValueMapTypeRemapper *TypeMapper = nullptr,
83                       ValueMaterializer *Materializer = nullptr);
84 
85   void RemapInstruction(Instruction *I, ValueToValueMapTy &VM,
86                         RemapFlags Flags = RF_None,
87                         ValueMapTypeRemapper *TypeMapper = nullptr,
88                         ValueMaterializer *Materializer = nullptr);
89 
90   /// MapValue - provide versions that preserve type safety for Constants.
91   inline Constant *MapValue(const Constant *V, ValueToValueMapTy &VM,
92                             RemapFlags Flags = RF_None,
93                             ValueMapTypeRemapper *TypeMapper = nullptr,
94                             ValueMaterializer *Materializer = nullptr) {
95     return cast<Constant>(MapValue((const Value*)V, VM, Flags, TypeMapper,
96                                    Materializer));
97   }
98 
99 } // End llvm namespace
100 
101 #endif
102