1 //===-- SemaConcept.h - Semantic Analysis for Constraints and Concepts ----===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file provides semantic analysis for C++ constraints and concepts.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_SEMA_SEMACONCEPT_H
15 #define LLVM_CLANG_SEMA_SEMACONCEPT_H
16 #include "clang/AST/ASTConcept.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/DeclTemplate.h"
20 #include "clang/Basic/SourceLocation.h"
21 #include "llvm/ADT/PointerUnion.h"
22 #include "llvm/ADT/Optional.h"
23 #include "llvm/ADT/SmallVector.h"
30 struct AtomicConstraint {
31 const Expr *ConstraintExpr;
32 Optional<MutableArrayRef<TemplateArgumentLoc>> ParameterMapping;
34 AtomicConstraint(Sema &S, const Expr *ConstraintExpr) :
35 ConstraintExpr(ConstraintExpr) { };
37 bool hasMatchingParameterMapping(ASTContext &C,
38 const AtomicConstraint &Other) const {
39 if (!ParameterMapping != !Other.ParameterMapping)
41 if (!ParameterMapping)
43 if (ParameterMapping->size() != Other.ParameterMapping->size())
46 for (unsigned I = 0, S = ParameterMapping->size(); I < S; ++I)
47 if (!C.getCanonicalTemplateArgument((*ParameterMapping)[I].getArgument())
48 .structurallyEquals(C.getCanonicalTemplateArgument(
49 (*Other.ParameterMapping)[I].getArgument())))
54 bool subsumes(ASTContext &C, const AtomicConstraint &Other) const {
55 // C++ [temp.constr.order] p2
56 // - an atomic constraint A subsumes another atomic constraint B
57 // if and only if the A and B are identical [...]
59 // C++ [temp.constr.atomic] p2
60 // Two atomic constraints are identical if they are formed from the
61 // same expression and the targets of the parameter mappings are
62 // equivalent according to the rules for expressions [...]
64 // We do not actually substitute the parameter mappings into the
65 // constraint expressions, therefore the constraint expressions are
66 // the originals, and comparing them will suffice.
67 if (ConstraintExpr != Other.ConstraintExpr)
70 // Check that the parameter lists are identical
71 return hasMatchingParameterMapping(C, Other);
75 /// \brief A normalized constraint, as defined in C++ [temp.constr.normal], is
76 /// either an atomic constraint, a conjunction of normalized constraints or a
77 /// disjunction of normalized constraints.
78 struct NormalizedConstraint {
81 enum CompoundConstraintKind { CCK_Conjunction, CCK_Disjunction };
83 using CompoundConstraint = llvm::PointerIntPair<
84 std::pair<NormalizedConstraint, NormalizedConstraint> *, 1,
85 CompoundConstraintKind>;
87 llvm::PointerUnion<AtomicConstraint *, CompoundConstraint> Constraint;
89 NormalizedConstraint(AtomicConstraint *C): Constraint{C} { };
90 NormalizedConstraint(ASTContext &C, NormalizedConstraint LHS,
91 NormalizedConstraint RHS, CompoundConstraintKind Kind)
92 : Constraint{CompoundConstraint{
93 new (C) std::pair<NormalizedConstraint, NormalizedConstraint>{
94 std::move(LHS), std::move(RHS)}, Kind}} { };
96 NormalizedConstraint(ASTContext &C, const NormalizedConstraint &Other) {
97 if (Other.isAtomic()) {
98 Constraint = new (C) AtomicConstraint(*Other.getAtomicConstraint());
100 Constraint = CompoundConstraint(
101 new (C) std::pair<NormalizedConstraint, NormalizedConstraint>{
102 NormalizedConstraint(C, Other.getLHS()),
103 NormalizedConstraint(C, Other.getRHS())},
104 Other.getCompoundKind());
107 NormalizedConstraint(NormalizedConstraint &&Other):
108 Constraint(Other.Constraint) {
109 Other.Constraint = nullptr;
111 NormalizedConstraint &operator=(const NormalizedConstraint &Other) = delete;
112 NormalizedConstraint &operator=(NormalizedConstraint &&Other) {
113 if (&Other != this) {
114 NormalizedConstraint Temp(std::move(Other));
115 std::swap(Constraint, Temp.Constraint);
120 CompoundConstraintKind getCompoundKind() const {
121 assert(!isAtomic() && "getCompoundKind called on atomic constraint.");
122 return Constraint.get<CompoundConstraint>().getInt();
125 bool isAtomic() const { return Constraint.is<AtomicConstraint *>(); }
127 NormalizedConstraint &getLHS() const {
128 assert(!isAtomic() && "getLHS called on atomic constraint.");
129 return Constraint.get<CompoundConstraint>().getPointer()->first;
132 NormalizedConstraint &getRHS() const {
133 assert(!isAtomic() && "getRHS called on atomic constraint.");
134 return Constraint.get<CompoundConstraint>().getPointer()->second;
137 AtomicConstraint *getAtomicConstraint() const {
139 "getAtomicConstraint called on non-atomic constraint.");
140 return Constraint.get<AtomicConstraint *>();
144 static Optional<NormalizedConstraint>
145 fromConstraintExprs(Sema &S, NamedDecl *D, ArrayRef<const Expr *> E);
146 static Optional<NormalizedConstraint>
147 fromConstraintExpr(Sema &S, NamedDecl *D, const Expr *E);
152 #endif //LLVM_CLANG_SEMA_SEMACONCEPT_H