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
|
//===--- PropertyRelations.cpp - Relations between property rules ---------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2021 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// Utility functions used during property map construction to record rewrite
// loops that describe certain special identities between rewrite rules that
// are discovered by the property map.
//
// For example, a superclass requirement implies an AnyObject layout
// requirement in the Swift language; if both are specified in some set of
// user-written requirements, the latter requirement is redundant and should
// be dropped from the minimal generic signature.
//
// This is described by recording a rewrite loop connecting the superclass rule
// and the AnyObject layout rule via a special rewrite step known as a
// "relation".
//
//===----------------------------------------------------------------------===//
#include "swift/AST/Type.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include "RewriteSystem.h"
using namespace swift;
using namespace rewriting;
RewriteSystem::Relation
RewriteSystem::getRelation(unsigned index) const {
return Relations[index];
}
/// Record a relation that transforms the left hand side when it appears
/// at the end of a term to the right hand side. Returns the relation ID,
/// which can be passed to RewriteStep::forRelation().
unsigned RewriteSystem::recordRelation(Term lhs, Term rhs) {
auto key = std::make_pair(lhs, rhs);
auto found = RelationMap.find(key);
if (found != RelationMap.end())
return found->second;
unsigned index = Relations.size();
Relations.push_back(key);
auto inserted = RelationMap.insert(std::make_pair(key, index));
assert(inserted.second);
(void) inserted;
return index;
}
/// Given a left-hand side symbol [p1] and a right-hand side symbol
/// [p2], record a relation ([p1].[p2] => [p1]), which denotes that
/// the property p1 implies the property p2.
///
/// An example is a superclass requirement that implies a layout
/// requirement.
unsigned RewriteSystem::recordRelation(Symbol lhsProperty,
Symbol rhsProperty) {
assert(lhsProperty.isProperty());
assert(rhsProperty.isProperty());
MutableTerm lhsTerm;
lhsTerm.add(lhsProperty);
lhsTerm.add(rhsProperty);
MutableTerm rhsTerm;
rhsTerm.add(lhsProperty);
// Record a relation ([p1].[p2] => [p1]).
return recordRelation(
Term::get(lhsTerm, Context),
Term::get(rhsTerm, Context));
}
/// Record a relation ([concrete: C].[P] => [concrete: C].[concrete: C : P])
/// or ([superclass: C].[P] => [superclass: C].[concrete: C : P]) which combines
/// a concrete type symbol (or a superclass symbol) with a protocol
/// symbol to form a single a concrete conformance symbol.
unsigned RewriteSystem::recordConcreteConformanceRelation(
Symbol concreteSymbol, Symbol protocolSymbol,
Symbol concreteConformanceSymbol) {
assert(protocolSymbol.getKind() == Symbol::Kind::Protocol);
assert(protocolSymbol.getProtocol() ==
concreteConformanceSymbol.getProtocol());
assert(concreteSymbol.getKind() == Symbol::Kind::Superclass ||
concreteSymbol.getKind() == Symbol::Kind::ConcreteType);
MutableTerm lhsTerm;
lhsTerm.add(concreteSymbol);
lhsTerm.add(protocolSymbol);
MutableTerm rhsTerm;
rhsTerm.add(concreteSymbol);
rhsTerm.add(concreteConformanceSymbol);
return recordRelation(
Term::get(lhsTerm, Context),
Term::get(rhsTerm, Context));
}
/// Record a relation ([concrete: C : P].[P:X].[concrete: C.X] =>
/// [concrete: C : P].[P:X]) which "concretizes" a nested type C.X of a
/// type parameter conforming to P known to equal the concrete type C.
unsigned RewriteSystem::recordConcreteTypeWitnessRelation(
Symbol concreteConformanceSymbol,
Symbol associatedTypeSymbol,
Symbol typeWitnessSymbol) {
assert(concreteConformanceSymbol.getKind() ==
Symbol::Kind::ConcreteConformance);
assert(associatedTypeSymbol.getKind() ==
Symbol::Kind::AssociatedType);
assert(concreteConformanceSymbol.getProtocol() ==
associatedTypeSymbol.getProtocol());
assert(typeWitnessSymbol.getKind() == Symbol::Kind::ConcreteType);
MutableTerm rhsTerm;
rhsTerm.add(concreteConformanceSymbol);
rhsTerm.add(associatedTypeSymbol);
MutableTerm lhsTerm(rhsTerm);
lhsTerm.add(typeWitnessSymbol);
return recordRelation(
Term::get(lhsTerm, Context),
Term::get(rhsTerm, Context));
}
/// Record a relation ([concrete: C : P].[P:X].[concrete: C] =>
/// [concrete: C : P].[P:X]) which "ties off" a nested type C.X that is
/// equivalent to C.
unsigned RewriteSystem::recordSameTypeWitnessRelation(
Symbol concreteConformanceSymbol,
Symbol associatedTypeSymbol) {
assert(concreteConformanceSymbol.getKind() ==
Symbol::Kind::ConcreteConformance);
assert(associatedTypeSymbol.getKind() ==
Symbol::Kind::AssociatedType);
MutableTerm rhsTerm;
rhsTerm.add(concreteConformanceSymbol);
auto concreteSymbol = Symbol::forConcreteType(
concreteConformanceSymbol.getConcreteType(),
concreteConformanceSymbol.getSubstitutions(),
Context);
MutableTerm lhsTerm(rhsTerm);
lhsTerm.add(associatedTypeSymbol);
lhsTerm.add(concreteSymbol);
return recordRelation(
Term::get(lhsTerm, Context),
Term::get(rhsTerm, Context));
}
|
