1//===--- MacroArgs.h - Formal argument info for Macros ----------*- 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// This file defines the MacroArgs interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LEX_MACROARGS_H
15#define LLVM_CLANG_LEX_MACROARGS_H
16
17#include "clang/Basic/LLVM.h"
18#include "clang/Lex/Token.h"
19#include "llvm/ADT/ArrayRef.h"
20#include "llvm/Support/TrailingObjects.h"
21#include <vector>
22
23namespace clang {
24  class MacroInfo;
25  class Preprocessor;
26  class SourceLocation;
27
28/// MacroArgs - An instance of this class captures information about
29/// the formal arguments specified to a function-like macro invocation.
30class MacroArgs final
31    : private llvm::TrailingObjects<MacroArgs, Token> {
32
33  friend TrailingObjects;
34  /// NumUnexpArgTokens - The number of raw, unexpanded tokens for the
35  /// arguments.  All of the actual argument tokens are allocated immediately
36  /// after the MacroArgs object in memory.  This is all of the arguments
37  /// concatenated together, with 'EOF' markers at the end of each argument.
38  unsigned NumUnexpArgTokens;
39
40  /// VarargsElided - True if this is a C99 style varargs macro invocation and
41  /// there was no argument specified for the "..." argument.  If the argument
42  /// was specified (even empty) or this isn't a C99 style varargs function, or
43  /// if in strict mode and the C99 varargs macro had only a ... argument, this
44  /// is false.
45  bool VarargsElided;
46
47  /// PreExpArgTokens - Pre-expanded tokens for arguments that need them.  Empty
48  /// if not yet computed.  This includes the EOF marker at the end of the
49  /// stream.
50  std::vector<std::vector<Token> > PreExpArgTokens;
51
52  /// StringifiedArgs - This contains arguments in 'stringified' form.  If the
53  /// stringified form of an argument has not yet been computed, this is empty.
54  std::vector<Token> StringifiedArgs;
55
56  /// ArgCache - This is a linked list of MacroArgs objects that the
57  /// Preprocessor owns which we use to avoid thrashing malloc/free.
58  MacroArgs *ArgCache;
59
60  /// MacroArgs - The number of arguments the invoked macro expects.
61  unsigned NumMacroArgs;
62
63  MacroArgs(unsigned NumToks, bool varargsElided, unsigned MacroArgs)
64      : NumUnexpArgTokens(NumToks), VarargsElided(varargsElided),
65        ArgCache(nullptr), NumMacroArgs(MacroArgs) {}
66  ~MacroArgs() = default;
67
68public:
69  /// MacroArgs ctor function - Create a new MacroArgs object with the specified
70  /// macro and argument info.
71  static MacroArgs *create(const MacroInfo *MI,
72                           ArrayRef<Token> UnexpArgTokens,
73                           bool VarargsElided, Preprocessor &PP);
74
75  /// destroy - Destroy and deallocate the memory for this object.
76  ///
77  void destroy(Preprocessor &PP);
78
79  /// ArgNeedsPreexpansion - If we can prove that the argument won't be affected
80  /// by pre-expansion, return false.  Otherwise, conservatively return true.
81  bool ArgNeedsPreexpansion(const Token *ArgTok, Preprocessor &PP) const;
82
83  /// getUnexpArgument - Return a pointer to the first token of the unexpanded
84  /// token list for the specified formal.
85  ///
86  const Token *getUnexpArgument(unsigned Arg) const;
87
88  /// getArgLength - Given a pointer to an expanded or unexpanded argument,
89  /// return the number of tokens, not counting the EOF, that make up the
90  /// argument.
91  static unsigned getArgLength(const Token *ArgPtr);
92
93  /// getPreExpArgument - Return the pre-expanded form of the specified
94  /// argument.
95  const std::vector<Token> &
96    getPreExpArgument(unsigned Arg, Preprocessor &PP);
97
98  /// getStringifiedArgument - Compute, cache, and return the specified argument
99  /// that has been 'stringified' as required by the # operator.
100  const Token &getStringifiedArgument(unsigned ArgNo, Preprocessor &PP,
101                                      SourceLocation ExpansionLocStart,
102                                      SourceLocation ExpansionLocEnd);
103
104  /// getNumMacroArguments - Return the number of arguments the invoked macro
105  /// expects.
106  unsigned getNumMacroArguments() const { return NumMacroArgs; }
107
108  /// isVarargsElidedUse - Return true if this is a C99 style varargs macro
109  /// invocation and there was no argument specified for the "..." argument.  If
110  /// the argument was specified (even empty) or this isn't a C99 style varargs
111  /// function, or if in strict mode and the C99 varargs macro had only a ...
112  /// argument, this returns false.
113  bool isVarargsElidedUse() const { return VarargsElided; }
114
115  /// Returns true if the macro was defined with a variadic (ellipsis) parameter
116  /// AND was invoked with at least one token supplied as a variadic argument.
117  ///
118  /// \code
119  ///   #define F(a)  a
120  ///   #define V(a, ...) __VA_OPT__(a)
121  ///   F()    <-- returns false on this invocation.
122  ///   V(,a)  <-- returns true on this invocation.
123  ///   V(,)   <-- returns false on this invocation.
124  /// \endcode
125  ///
126
127  bool invokedWithVariadicArgument(const MacroInfo *const MI) const;
128
129  /// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
130  /// tokens into the literal string token that should be produced by the C #
131  /// preprocessor operator.  If Charify is true, then it should be turned into
132  /// a character literal for the Microsoft charize (#@) extension.
133  ///
134  static Token StringifyArgument(const Token *ArgToks,
135                                 Preprocessor &PP, bool Charify,
136                                 SourceLocation ExpansionLocStart,
137                                 SourceLocation ExpansionLocEnd);
138
139
140  /// deallocate - This should only be called by the Preprocessor when managing
141  /// its freelist.
142  MacroArgs *deallocate();
143};
144
145}  // end namespace clang
146
147#endif
148