MacroArgs.cpp revision 193326 
1//===--- TokenLexer.cpp - Lex from a token stream -------------------------===//
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 implements the TokenLexer interface.
11//
12//===----------------------------------------------------------------------===//
13
14#include "MacroArgs.h"
15#include "clang/Lex/MacroInfo.h"
16#include "clang/Lex/Preprocessor.h"
17#include "clang/Lex/LexDiagnostic.h"
18using namespace clang;
19
20/// MacroArgs ctor function - This destroys the vector passed in.
21MacroArgs *MacroArgs::create(const MacroInfo *MI,
22                             const Token *UnexpArgTokens,
23                             unsigned NumToks, bool VarargsElided) {
24  assert(MI->isFunctionLike() &&
25         "Can't have args for an object-like macro!");
26
27  // Allocate memory for the MacroArgs object with the lexer tokens at the end.
28  MacroArgs *Result = (MacroArgs*)malloc(sizeof(MacroArgs) +
29                                         NumToks*sizeof(Token));
30  // Construct the macroargs object.
31  new (Result) MacroArgs(NumToks, VarargsElided);
32
33  // Copy the actual unexpanded tokens to immediately after the result ptr.
34  if (NumToks)
35    memcpy(const_cast<Token*>(Result->getUnexpArgument(0)),
36           UnexpArgTokens, NumToks*sizeof(Token));
37
38  return Result;
39}
40
41/// destroy - Destroy and deallocate the memory for this object.
42///
43void MacroArgs::destroy() {
44  // Run the dtor to deallocate the vectors.
45  this->~MacroArgs();
46  // Release the memory for the object.
47  free(this);
48}
49
50
51/// getArgLength - Given a pointer to an expanded or unexpanded argument,
52/// return the number of tokens, not counting the EOF, that make up the
53/// argument.
54unsigned MacroArgs::getArgLength(const Token *ArgPtr) {
55  unsigned NumArgTokens = 0;
56  for (; ArgPtr->isNot(tok::eof); ++ArgPtr)
57    ++NumArgTokens;
58  return NumArgTokens;
59}
60
61
62/// getUnexpArgument - Return the unexpanded tokens for the specified formal.
63///
64const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
65  // The unexpanded argument tokens start immediately after the MacroArgs object
66  // in memory.
67  const Token *Start = (const Token *)(this+1);
68  const Token *Result = Start;
69  // Scan to find Arg.
70  for (; Arg; ++Result) {
71    assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
72    if (Result->is(tok::eof))
73      --Arg;
74  }
75  assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
76  return Result;
77}
78
79
80/// ArgNeedsPreexpansion - If we can prove that the argument won't be affected
81/// by pre-expansion, return false.  Otherwise, conservatively return true.
82bool MacroArgs::ArgNeedsPreexpansion(const Token *ArgTok,
83                                     Preprocessor &PP) const {
84  // If there are no identifiers in the argument list, or if the identifiers are
85  // known to not be macros, pre-expansion won't modify it.
86  for (; ArgTok->isNot(tok::eof); ++ArgTok)
87    if (IdentifierInfo *II = ArgTok->getIdentifierInfo()) {
88      if (II->hasMacroDefinition() && PP.getMacroInfo(II)->isEnabled())
89        // Return true even though the macro could be a function-like macro
90        // without a following '(' token.
91        return true;
92    }
93  return false;
94}
95
96/// getPreExpArgument - Return the pre-expanded form of the specified
97/// argument.
98const std::vector<Token> &
99MacroArgs::getPreExpArgument(unsigned Arg, Preprocessor &PP) {
100  assert(Arg < NumUnexpArgTokens && "Invalid argument number!");
101
102  // If we have already computed this, return it.
103  if (PreExpArgTokens.empty())
104    PreExpArgTokens.resize(NumUnexpArgTokens);
105
106  std::vector<Token> &Result = PreExpArgTokens[Arg];
107  if (!Result.empty()) return Result;
108
109  const Token *AT = getUnexpArgument(Arg);
110  unsigned NumToks = getArgLength(AT)+1;  // Include the EOF.
111
112  // Otherwise, we have to pre-expand this argument, populating Result.  To do
113  // this, we set up a fake TokenLexer to lex from the unexpanded argument
114  // list.  With this installed, we lex expanded tokens until we hit the EOF
115  // token at the end of the unexp list.
116  PP.EnterTokenStream(AT, NumToks, false /*disable expand*/,
117                      false /*owns tokens*/);
118
119  // Lex all of the macro-expanded tokens into Result.
120  do {
121    Result.push_back(Token());
122    Token &Tok = Result.back();
123    PP.Lex(Tok);
124  } while (Result.back().isNot(tok::eof));
125
126  // Pop the token stream off the top of the stack.  We know that the internal
127  // pointer inside of it is to the "end" of the token stream, but the stack
128  // will not otherwise be popped until the next token is lexed.  The problem is
129  // that the token may be lexed sometime after the vector of tokens itself is
130  // destroyed, which would be badness.
131  PP.RemoveTopOfLexerStack();
132  return Result;
133}
134
135
136/// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of
137/// tokens into the literal string token that should be produced by the C #
138/// preprocessor operator.  If Charify is true, then it should be turned into
139/// a character literal for the Microsoft charize (#@) extension.
140///
141Token MacroArgs::StringifyArgument(const Token *ArgToks,
142                                   Preprocessor &PP, bool Charify) {
143  Token Tok;
144  Tok.startToken();
145  Tok.setKind(tok::string_literal);
146
147  const Token *ArgTokStart = ArgToks;
148
149  // Stringify all the tokens.
150  llvm::SmallString<128> Result;
151  Result += "\"";
152
153  bool isFirst = true;
154  for (; ArgToks->isNot(tok::eof); ++ArgToks) {
155    const Token &Tok = *ArgToks;
156    if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine()))
157      Result += ' ';
158    isFirst = false;
159
160    // If this is a string or character constant, escape the token as specified
161    // by 6.10.3.2p2.
162    if (Tok.is(tok::string_literal) ||       // "foo"
163        Tok.is(tok::wide_string_literal) ||  // L"foo"
164        Tok.is(tok::char_constant)) {        // 'x' and L'x'.
165      std::string Str = Lexer::Stringify(PP.getSpelling(Tok));
166      Result.append(Str.begin(), Str.end());
167    } else {
168      // Otherwise, just append the token.  Do some gymnastics to get the token
169      // in place and avoid copies where possible.
170      unsigned CurStrLen = Result.size();
171      Result.resize(CurStrLen+Tok.getLength());
172      const char *BufPtr = &Result[CurStrLen];
173      unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr);
174
175      // If getSpelling returned a pointer to an already uniqued version of the
176      // string instead of filling in BufPtr, memcpy it onto our string.
177      if (BufPtr != &Result[CurStrLen])
178        memcpy(&Result[CurStrLen], BufPtr, ActualTokLen);
179
180      // If the token was dirty, the spelling may be shorter than the token.
181      if (ActualTokLen != Tok.getLength())
182        Result.resize(CurStrLen+ActualTokLen);
183    }
184  }
185
186  // If the last character of the string is a \, and if it isn't escaped, this
187  // is an invalid string literal, diagnose it as specified in C99.
188  if (Result.back() == '\\') {
189    // Count the number of consequtive \ characters.  If even, then they are
190    // just escaped backslashes, otherwise it's an error.
191    unsigned FirstNonSlash = Result.size()-2;
192    // Guaranteed to find the starting " if nothing else.
193    while (Result[FirstNonSlash] == '\\')
194      --FirstNonSlash;
195    if ((Result.size()-1-FirstNonSlash) & 1) {
196      // Diagnose errors for things like: #define F(X) #X   /   F(\)
197      PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal);
198      Result.pop_back();  // remove one of the \'s.
199    }
200  }
201  Result += '"';
202
203  // If this is the charify operation and the result is not a legal character
204  // constant, diagnose it.
205  if (Charify) {
206    // First step, turn double quotes into single quotes:
207    Result[0] = '\'';
208    Result[Result.size()-1] = '\'';
209
210    // Check for bogus character.
211    bool isBad = false;
212    if (Result.size() == 3)
213      isBad = Result[1] == '\'';   // ''' is not legal. '\' already fixed above.
214    else
215      isBad = (Result.size() != 4 || Result[1] != '\\');  // Not '\x'
216
217    if (isBad) {
218      PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify);
219      Result = "' '";  // Use something arbitrary, but legal.
220    }
221  }
222
223  PP.CreateString(&Result[0], Result.size(), Tok);
224  return Tok;
225}
226
227/// getStringifiedArgument - Compute, cache, and return the specified argument
228/// that has been 'stringified' as required by the # operator.
229const Token &MacroArgs::getStringifiedArgument(unsigned ArgNo,
230                                               Preprocessor &PP) {
231  assert(ArgNo < NumUnexpArgTokens && "Invalid argument number!");
232  if (StringifiedArgs.empty()) {
233    StringifiedArgs.resize(getNumArguments());
234    memset(&StringifiedArgs[0], 0,
235           sizeof(StringifiedArgs[0])*getNumArguments());
236  }
237  if (StringifiedArgs[ArgNo].isNot(tok::string_literal))
238    StringifiedArgs[ArgNo] = StringifyArgument(getUnexpArgument(ArgNo), PP);
239  return StringifiedArgs[ArgNo];
240}
241