1//===--- MacroArgs.h - Formal argument info for Macros ----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the MacroArgs interface.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_LEX_MACROARGS_H
14#define LLVM_CLANG_LEX_MACROARGS_H
15
16#include "clang/Basic/LLVM.h"
17#include "clang/Lex/Token.h"
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/Support/TrailingObjects.h"
20#include <vector>
21
22namespace clang {
23 class MacroInfo;
24 class Preprocessor;
25 class SourceLocation;
26
27/// MacroArgs - An instance of this class captures information about
28/// the formal arguments specified to a function-like macro invocation.
29class MacroArgs final
30 : private llvm::TrailingObjects<MacroArgs, Token> {
31
32 friend TrailingObjects;
33 /// NumUnexpArgTokens - The number of raw, unexpanded tokens for the
34 /// arguments. All of the actual argument tokens are allocated immediately
35 /// after the MacroArgs object in memory. This is all of the arguments
36 /// concatenated together, with 'EOF' markers at the end of each argument.
37 unsigned NumUnexpArgTokens;
38
39 /// VarargsElided - True if this is a C99 style varargs macro invocation and
40 /// there was no argument specified for the "..." argument. If the argument
41 /// was specified (even empty) or this isn't a C99 style varargs function, or
42 /// if in strict mode and the C99 varargs macro had only a ... argument, this
43 /// is false.
44 bool VarargsElided;
45
46 /// PreExpArgTokens - Pre-expanded tokens for arguments that need them. Empty
47 /// if not yet computed. This includes the EOF marker at the end of the
48 /// stream.
49 std::vector<std::vector<Token> > PreExpArgTokens;
50
51 /// ArgCache - This is a linked list of MacroArgs objects that the
52 /// Preprocessor owns which we use to avoid thrashing malloc/free.
53 MacroArgs *ArgCache;
54
55 /// MacroArgs - The number of arguments the invoked macro expects.
56 unsigned NumMacroArgs;
57
58 MacroArgs(unsigned NumToks, bool varargsElided, unsigned MacroArgs)
59 : NumUnexpArgTokens(NumToks), VarargsElided(varargsElided),
60 ArgCache(nullptr), NumMacroArgs(MacroArgs) {}
61 ~MacroArgs() = default;
62
63public:
64 /// MacroArgs ctor function - Create a new MacroArgs object with the specified
65 /// macro and argument info.
66 static MacroArgs *create(const MacroInfo *MI,
67 ArrayRef<Token> UnexpArgTokens,
68 bool VarargsElided, Preprocessor &PP);
69
70 /// destroy - Destroy and deallocate the memory for this object.
71 ///
72 void destroy(Preprocessor &PP);
73
74 /// ArgNeedsPreexpansion - If we can prove that the argument won't be affected
75 /// by pre-expansion, return false. Otherwise, conservatively return true.
76 bool ArgNeedsPreexpansion(const Token *ArgTok, Preprocessor &PP) const;
77
78 /// getUnexpArgument - Return a pointer to the first token of the unexpanded
79 /// token list for the specified formal.
80 ///
81 const Token *getUnexpArgument(unsigned Arg) const;
82
83 /// getArgLength - Given a pointer to an expanded or unexpanded argument,
84 /// return the number of tokens, not counting the EOF, that make up the
85 /// argument.
86 static unsigned getArgLength(const Token *ArgPtr);
87
88 /// getPreExpArgument - Return the pre-expanded form of the specified
89 /// argument.
90 const std::vector<Token> &
91 getPreExpArgument(unsigned Arg, Preprocessor &PP);
92
93 /// getNumMacroArguments - Return the number of arguments the invoked macro
94 /// expects.
95 unsigned getNumMacroArguments() const { return NumMacroArgs; }
96
97 /// isVarargsElidedUse - Return true if this is a C99 style varargs macro
98 /// invocation and there was no argument specified for the "..." argument. If
99 /// the argument was specified (even empty) or this isn't a C99 style varargs
100 /// function, or if in strict mode and the C99 varargs macro had only a ...
101 /// argument, this returns false.
102 bool isVarargsElidedUse() const { return VarargsElided; }
103
104 /// Returns true if the macro was defined with a variadic (ellipsis) parameter
105 /// AND was invoked with at least one token supplied as a variadic argument
106 /// (after pre-expansion).
107 ///
108 /// \code
109 /// #define F(a) a
110 /// #define V(a, ...) __VA_OPT__(a)
111 /// F() <-- returns false on this invocation.
112 /// V(,a) <-- returns true on this invocation.
113 /// V(,) <-- returns false on this invocation.
114 /// V(,F()) <-- returns false on this invocation.
115 /// \endcode
116 ///
117 bool invokedWithVariadicArgument(const MacroInfo *const MI, Preprocessor &PP);
118
119 /// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
120 /// tokens into the literal string token that should be produced by the C #
121 /// preprocessor operator. If Charify is true, then it should be turned into
122 /// a character literal for the Microsoft charize (#@) extension.
123 ///
124 static Token StringifyArgument(const Token *ArgToks,
125 Preprocessor &PP, bool Charify,
126 SourceLocation ExpansionLocStart,
127 SourceLocation ExpansionLocEnd);
128
129
130 /// deallocate - This should only be called by the Preprocessor when managing
131 /// its freelist.
132 MacroArgs *deallocate();
133};
134
135} // end namespace clang
136
137#endif
138