1/* CPP Library - directive only preprocessing for distributed compilation.
2   Copyright (C) 2007
3   Free Software Foundation, Inc.
4   Contributed by Ollie Wild <aaw@google.com>.
5
6This program is free software; you can redistribute it and/or modify it
7under the terms of the GNU General Public License as published by the
8Free Software Foundation; either version 2, or (at your option) any
9later version.
10
11This program is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with this program; if not, write to the Free Software
18Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
19
20#include "config.h"
21#include "system.h"
22#include "cpplib.h"
23#include "internal.h"
24
25/* DO (Directive only) flags. */
26#define DO_BOL		 (1 << 0) /* At the beginning of a logical line. */
27#define DO_STRING	 (1 << 1) /* In a string constant. */
28#define DO_CHAR		 (1 << 2) /* In a character constant. */
29#define DO_BLOCK_COMMENT (1 << 3) /* In a block comment. */
30#define DO_LINE_COMMENT	 (1 << 4) /* In a single line "//-style" comment. */
31
32#define DO_LINE_SPECIAL (DO_STRING | DO_CHAR | DO_LINE_COMMENT)
33#define DO_SPECIAL	(DO_LINE_SPECIAL | DO_BLOCK_COMMENT)
34
35/* Writes out the preprocessed file, handling spacing and paste
36   avoidance issues.  */
37void
38_cpp_preprocess_dir_only (cpp_reader *pfile,
39			  const struct _cpp_dir_only_callbacks *cb)
40{
41  struct cpp_buffer *buffer;
42  const unsigned char *cur, *base, *next_line, *rlimit;
43  cppchar_t c, last_c;
44  unsigned flags;
45  int lines, col;
46  source_location loc;
47
48 restart:
49  /* Buffer initialization ala _cpp_clean_line(). */
50  buffer = pfile->buffer;
51  buffer->cur_note = buffer->notes_used = 0;
52  buffer->cur = buffer->line_base = buffer->next_line;
53  buffer->need_line = false;
54
55  /* This isn't really needed.  It prevents a compiler warning, though. */
56  loc = pfile->line_table->highest_line;
57
58  /* Scan initialization. */
59  next_line = cur = base = buffer->cur;
60  rlimit = buffer->rlimit;
61  flags = DO_BOL;
62  lines = 0;
63  col = 1;
64
65  for (last_c = '\n', c = *cur; cur < rlimit; last_c = c, c = *++cur, ++col)
66    {
67      /* Skip over escaped newlines. */
68      if (__builtin_expect (c == '\\', false))
69	{
70	  const unsigned char *tmp = cur + 1;
71
72	  while (is_nvspace (*tmp) && tmp < rlimit)
73	    tmp++;
74	  if (*tmp == '\r')
75	    tmp++;
76	  if (*tmp == '\n' && tmp < rlimit)
77	    {
78	      CPP_INCREMENT_LINE (pfile, 0);
79	      lines++;
80	      col = 0;
81	      cur = tmp;
82	      c = last_c;
83	      continue;
84	    }
85	}
86
87      if (__builtin_expect (last_c == '#', false) && !(flags & DO_SPECIAL))
88	{
89	  if (c != '#' && (flags & DO_BOL))
90	  {
91	    struct line_maps *line_table;
92
93	    if (!pfile->state.skipping && next_line != base)
94	      cb->print_lines (lines, base, next_line - base);
95
96	    /* Prep things for directive handling. */
97	    buffer->next_line = cur;
98	    buffer->need_line = true;
99	    _cpp_get_fresh_line (pfile);
100
101	    /* Ensure proper column numbering for generated error messages. */
102	    buffer->line_base -= col - 1;
103
104	    _cpp_handle_directive (pfile, 0 /* ignore indented */);
105
106	    /* Sanitize the line settings.  Duplicate #include's can mess
107	       things up. */
108	    line_table = pfile->line_table;
109	    line_table->highest_location = line_table->highest_line;
110
111	    /* The if block prevents us from outputing line information when
112	       the file ends with a directive and no newline.  Note that we
113	       must use pfile->buffer, not buffer. */
114	    if (pfile->buffer->cur != pfile->buffer->rlimit)
115	      cb->maybe_print_line (pfile->line_table->highest_line);
116
117	    goto restart;
118	  }
119
120	  flags &= ~DO_BOL;
121	  pfile->mi_valid = false;
122	}
123      else if (__builtin_expect (last_c == '/', false) \
124	       && !(flags & DO_SPECIAL) && c != '*' && c != '/')
125	{
126	  /* If a previous slash is not starting a block comment, clear the
127	     DO_BOL flag.  */
128	  flags &= ~DO_BOL;
129	  pfile->mi_valid = false;
130	}
131
132      switch (c)
133	{
134	case '/':
135	  if ((flags & DO_BLOCK_COMMENT) && last_c == '*')
136	    {
137	      flags &= ~DO_BLOCK_COMMENT;
138	      c = 0;
139	    }
140	  else if (!(flags & DO_SPECIAL) && last_c == '/')
141	    flags |= DO_LINE_COMMENT;
142	  else if (!(flags & DO_SPECIAL))
143	    /* Mark the position for possible error reporting. */
144	    LINEMAP_POSITION_FOR_COLUMN (loc, pfile->line_table, col);
145
146	  break;
147
148	case '*':
149	  if (!(flags & DO_SPECIAL))
150	    {
151	      if (last_c == '/')
152		flags |= DO_BLOCK_COMMENT;
153	      else
154		{
155		  flags &= ~DO_BOL;
156		  pfile->mi_valid = false;
157		}
158	    }
159
160	  break;
161
162	case '\'':
163	case '"':
164	  {
165	    unsigned state = (c == '"') ? DO_STRING : DO_CHAR;
166
167	    if (!(flags & DO_SPECIAL))
168	      {
169		flags |= state;
170		flags &= ~DO_BOL;
171		pfile->mi_valid = false;
172	      }
173	    else if ((flags & state) && last_c != '\\')
174	      flags &= ~state;
175
176	    break;
177	  }
178
179	case '\\':
180	  {
181	    if ((flags & (DO_STRING | DO_CHAR)) && last_c == '\\')
182	      c = 0;
183
184	    if (!(flags & DO_SPECIAL))
185	      {
186		flags &= ~DO_BOL;
187		pfile->mi_valid = false;
188	      }
189
190	    break;
191	  }
192
193	case '\n':
194	  CPP_INCREMENT_LINE (pfile, 0);
195	  lines++;
196	  col = 0;
197	  flags &= ~DO_LINE_SPECIAL;
198	  if (!(flags & DO_SPECIAL))
199	    flags |= DO_BOL;
200	  break;
201
202	case '#':
203	  next_line = cur;
204	  /* Don't update DO_BOL yet. */
205	  break;
206
207	case ' ': case '\t': case '\f': case '\v': case '\0':
208	  break;
209
210	default:
211	  if (!(flags & DO_SPECIAL))
212	    {
213	      flags &= ~DO_BOL;
214	      pfile->mi_valid = false;
215	    }
216	  break;
217	}
218    }
219
220  if (flags & DO_BLOCK_COMMENT)
221    cpp_error_with_line (pfile, CPP_DL_ERROR, loc, 0, "unterminated comment");
222
223  if (!pfile->state.skipping && cur != base)
224    cb->print_lines (lines, base, cur - base);
225
226  _cpp_pop_buffer (pfile);
227  if (pfile->buffer)
228    goto restart;
229}
230