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
|
//===-- llvm/AbstractTypeUser.h - AbstractTypeUser Interface -----*- C++ -*--=//
//
// The AbstractTypeUser class is an interface to be implemented by classes who
// could possible use an abstract type. Abstract types are denoted by the
// isAbstract flag set to true in the Type class. These are classes that
// contain an Opaque type in their structure somehow.
//
// Classes must implement this interface so that they may be notified when an
// abstract type is resolved. Abstract types may be resolved into more concrete
// types through: linking, parsing, and bytecode reading. When this happens,
// all of the users of the type must be updated to reference the new, more
// concrete type. They are notified through the AbstractTypeUser interface.
//
// In addition to this, AbstractTypeUsers must keep the use list of the
// potentially abstract type that they reference up-to-date. To do this in a
// nice, transparent way, the PATypeHandle class is used to hold "Potentially
// Abstract Types", and keep the use list of the abstract types up-to-date.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ABSTRACT_TYPE_USER_H
#define LLVM_ABSTRACT_TYPE_USER_H
class Type;
class DerivedType;
class AbstractTypeUser {
protected:
virtual ~AbstractTypeUser() {} // Derive from me
public:
// refineAbstractType - The callback method invoked when an abstract type
// has been found to be more concrete. A class must override this method to
// update its internal state to reference NewType instead of OldType. Soon
// after this method is invoked, OldType shall be deleted, so referencing it
// is quite unwise.
//
// Another case that is important to consider is when a type is refined, but
// stays in the same place in memory. In this case OldTy will equal NewTy.
// This callback just notifies ATU's that the underlying structure of the type
// has changed... but any previously used properties are still valid.
//
// Note that it is possible to refine a type with parameters OldTy==NewTy, and
// OldTy is no longer abstract. In this case, abstract type users should
// release their hold on a type, because it went from being abstract to
// concrete.
//
virtual void refineAbstractType(const DerivedType *OldTy,
const Type *NewTy) = 0;
// for debugging...
virtual void dump() const = 0;
};
// PATypeHandle - Handle to a Type subclass. This class is parameterized so
// that users can have handles to MethodType's that are still specialized, for
// example. This class is a simple class used to keep the use list of abstract
// types up-to-date.
//
template <class TypeSubClass>
class PATypeHandle {
const TypeSubClass *Ty;
AbstractTypeUser * const User;
// These functions are defined at the bottom of Type.h. See the comment there
// for justification.
inline void addUser();
inline void removeUser();
public:
// ctor - Add use to type if abstract. Note that Ty must not be null
inline PATypeHandle(const TypeSubClass *ty, AbstractTypeUser *user)
: Ty(ty), User(user) {
addUser();
}
// ctor - Add use to type if abstract.
inline PATypeHandle(const PATypeHandle &T) : Ty(T.Ty), User(T.User) {
addUser();
}
// dtor - Remove reference to type...
inline ~PATypeHandle() { removeUser(); }
// Automatic casting operator so that the handle may be used naturally
inline operator const TypeSubClass *() const { return Ty; }
inline const TypeSubClass *get() const { return Ty; }
// operator= - Allow assignment to handle
inline const TypeSubClass *operator=(const TypeSubClass *ty) {
if (Ty != ty) { // Ensure we don't accidentally drop last ref to Ty
removeUser();
Ty = ty;
addUser();
}
return Ty;
}
// operator= - Allow assignment to handle
inline const TypeSubClass *operator=(const PATypeHandle &T) {
return operator=(T.Ty);
}
inline bool operator==(const TypeSubClass *ty) {
return Ty == ty;
}
// operator-> - Allow user to dereference handle naturally...
inline const TypeSubClass *operator->() const { return Ty; }
// removeUserFromConcrete - This function should be called when the User is
// notified that our type is refined... and the type is being refined to
// itself, which is now a concrete type. When a type becomes concrete like
// this, we MUST remove ourself from the AbstractTypeUser list, even though
// the type is apparently concrete.
//
inline void removeUserFromConcrete();
};
// PATypeHolder - Holder class for a potentially abstract type. This functions
// as both a handle (as above) and an AbstractTypeUser. It uses the callback to
// keep its pointer member updated to the current version of the type.
//
struct PATypeHolder : public AbstractTypeUser, public PATypeHandle<Type> {
inline PATypeHolder(const Type *ty) : PATypeHandle<Type>(ty, this) {}
inline PATypeHolder(const PATypeHolder &T)
: AbstractTypeUser(T), PATypeHandle<Type>(T, this) {}
// refineAbstractType - All we do is update our PATypeHandle member to point
// to the new type.
//
virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
assert(get() == (const Type*)OldTy && "Can't refine to unknown value!");
// Check to see if the type just became concrete. If so, we have to
// removeUser to get off its AbstractTypeUser list
removeUserFromConcrete();
if ((const Type*)OldTy != NewTy)
PATypeHandle<Type>::operator=(NewTy);
}
// operator= - Allow assignment to handle
inline const Type *operator=(const Type *ty) {
return PATypeHandle<Type>::operator=(ty);
}
// operator= - Allow assignment to handle
inline const Type *operator=(const PATypeHandle<Type> &T) {
return PATypeHandle<Type>::operator=(T);
}
inline const Type *operator=(const PATypeHolder &H) {
return PATypeHandle<Type>::operator=(H);
}
void dump() const;
};
#endif
|
