MacroArgs.h revision 360784 
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