1//===--- LambdaCapture.h - Types for C++ Lambda Captures --------*- 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/// \file
11/// Defines the LambdaCapture class.
12///
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_AST_LAMBDACAPTURE_H
16#define LLVM_CLANG_AST_LAMBDACAPTURE_H
17
18#include "clang/AST/Decl.h"
19#include "clang/Basic/Lambda.h"
20#include "llvm/ADT/PointerIntPair.h"
21
22namespace clang {
23
24/// Describes the capture of a variable or of \c this, or of a
25/// C++1y init-capture.
26class LambdaCapture {
27 enum {
28 /// Flag used by the Capture class to indicate that the given
29 /// capture was implicit.
30 Capture_Implicit = 0x01,
31
32 /// Flag used by the Capture class to indicate that the
33 /// given capture was by-copy.
34 ///
35 /// This includes the case of a non-reference init-capture.
36 Capture_ByCopy = 0x02,
37
38 /// Flag used by the Capture class to distinguish between a capture
39 /// of '*this' and a capture of a VLA type.
40 Capture_This = 0x04
41 };
42
43 // Decl could represent:
44 // - a VarDecl* that represents the variable that was captured or the
45 // init-capture.
46 // - or, is a nullptr and Capture_This is set in Bits if this represents a
47 // capture of '*this' by value or reference.
48 // - or, is a nullptr and Capture_This is not set in Bits if this represents
49 // a capture of a VLA type.
50 llvm::PointerIntPair<Decl*, 3> DeclAndBits;
51
52 SourceLocation Loc;
53 SourceLocation EllipsisLoc;
54
55 friend class ASTStmtReader;
56 friend class ASTStmtWriter;
57
58public:
59 /// Create a new capture of a variable or of \c this.
60 ///
61 /// \param Loc The source location associated with this capture.
62 ///
63 /// \param Kind The kind of capture (this, byref, bycopy), which must
64 /// not be init-capture.
65 ///
66 /// \param Implicit Whether the capture was implicit or explicit.
67 ///
68 /// \param Var The local variable being captured, or null if capturing
69 /// \c this.
70 ///
71 /// \param EllipsisLoc The location of the ellipsis (...) for a
72 /// capture that is a pack expansion, or an invalid source
73 /// location to indicate that this is not a pack expansion.
74 LambdaCapture(SourceLocation Loc, bool Implicit, LambdaCaptureKind Kind,
75 VarDecl *Var = nullptr,
76 SourceLocation EllipsisLoc = SourceLocation());
77
78 /// Determine the kind of capture.
79 LambdaCaptureKind getCaptureKind() const;
80
81 /// Determine whether this capture handles the C++ \c this
82 /// pointer.
83 bool capturesThis() const {
84 return DeclAndBits.getPointer() == nullptr &&
85 (DeclAndBits.getInt() & Capture_This);
86 }
87
88 /// Determine whether this capture handles a variable.
89 bool capturesVariable() const {
90 return dyn_cast_or_null<VarDecl>(DeclAndBits.getPointer());
91 }
92
93 /// Determine whether this captures a variable length array bound
94 /// expression.
95 bool capturesVLAType() const {
96 return DeclAndBits.getPointer() == nullptr &&
97 !(DeclAndBits.getInt() & Capture_This);
98 }
99
100 /// Retrieve the declaration of the local variable being
101 /// captured.
102 ///
103 /// This operation is only valid if this capture is a variable capture
104 /// (other than a capture of \c this).
105 VarDecl *getCapturedVar() const {
106 assert(capturesVariable() && "No variable available for capture");
107 return static_cast<VarDecl *>(DeclAndBits.getPointer());
108 }
109
110 /// Determine whether this was an implicit capture (not
111 /// written between the square brackets introducing the lambda).
112 bool isImplicit() const {
113 return DeclAndBits.getInt() & Capture_Implicit;
114 }
115
116 /// Determine whether this was an explicit capture (written
117 /// between the square brackets introducing the lambda).
118 bool isExplicit() const { return !isImplicit(); }
119
120 /// Retrieve the source location of the capture.
121 ///
122 /// For an explicit capture, this returns the location of the
123 /// explicit capture in the source. For an implicit capture, this
124 /// returns the location at which the variable or \c this was first
125 /// used.
126 SourceLocation getLocation() const { return Loc; }
127
128 /// Determine whether this capture is a pack expansion,
129 /// which captures a function parameter pack.
130 bool isPackExpansion() const { return EllipsisLoc.isValid(); }
131
132 /// Retrieve the location of the ellipsis for a capture
133 /// that is a pack expansion.
134 SourceLocation getEllipsisLoc() const {
135 assert(isPackExpansion() && "No ellipsis location for a non-expansion");
136 return EllipsisLoc;
137 }
138};
139
140} // end namespace clang
141
142#endif // LLVM_CLANG_AST_LAMBDACAPTURE_H
143