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