gcc/scan-decls.c

   1 /* scan-decls.c - Extracts declarations from cpp output.
   2    Copyright (C) 1993, 1995, 1997, 1998 Free Software Foundation, Inc.
   3
   4 This program is free software; you can redistribute it and/or modify it
   5 under the terms of the GNU General Public License as published by the
   6 Free Software Foundation; either version 2, or (at your option) any
   7 later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17
  18    Written by Per Bothner <bothner@cygnus.com>, July 1993.  */
  19
  20 #include "hconfig.h"
  21 #include "system.h"
  22 #include "gansidecl.h"
  23 #include "cpplib.h"
  24 #include "scan.h"
  25
  26 int brace_nesting = 0;
  27
  28 /* The first extern_C_braces_length elements of extern_C_braces
  29    indicate the (brace nesting levels of) left braces that were
  30    prefixed by extern "C".  */
  31 int extern_C_braces_length = 0;
  32 char extern_C_braces[20];
  33 #define in_extern_C_brace (extern_C_braces_length>0)
  34
  35 /* True if the function declaration currently being scanned is
  36    prefixed by extern "C".  */
  37 int current_extern_C = 0;
  38
  39 static void
  40 skip_to_closing_brace (pfile)
  41      cpp_reader *pfile;
  42 {
  43   int nesting = 1;
  44   for (;;)
  45     {
  46       enum cpp_token token = cpp_get_token (pfile);
  47       if (token == CPP_EOF)
  48         break;
  49       if (token == CPP_LBRACE)
  50         nesting++;
  51       if (token == CPP_RBRACE && --nesting == 0)
  52         break;
  53     }
  54 }
  55
  56 /* This function scans a C source file (actually, the output of cpp),
  57    reading from FP.  It looks for function declarations, and
  58    external variable declarations.
  59
  60    The following grammar (as well as some extra stuff) is recognized:
  61
  62    declaration:
  63      (decl-specifier)* declarator ("," declarator)* ";"
  64    decl-specifier:
  65      identifier
  66      keyword
  67      extern "C"
  68    declarator:
  69      (ptr-operator)* dname [ "(" argument-declaration-list ")" ]
  70    ptr-operator:
  71      ("*" | "&") ("const" | "volatile")*
  72    dname:
  73      identifier
  74
  75 Here dname is the actual name being declared.
  76 */
  77
  78 int
  79 scan_decls (pfile, argc, argv)
  80      cpp_reader *pfile;
  81      int argc;
  82      char **argv;
  83 {
  84   int saw_extern, saw_inline;
  85   int start_written;
  86   /* If declarator_start is non-zero, it marks the start of the current
  87      declarator.  If it is zero, we are either still parsing the
  88      decl-specs, or prev_id_start marks the start of the declarator.  */
  89   int declarator_start;
  90   int prev_id_start, prev_id_end;
  91   enum cpp_token token;
  92
  93  new_statement:
  94   CPP_SET_WRITTEN (pfile, 0);
  95   start_written = 0;
  96   token = cpp_get_token (pfile);
  97
  98  handle_statement:
  99   current_extern_C = 0;
 100   saw_extern = 0;
 101   saw_inline = 0;
 102   if (token == CPP_RBRACE)
 103     {
 104       /* Pop an 'extern "C"' nesting level, if appropriate.  */
 105       if (extern_C_braces_length
 106           && extern_C_braces[extern_C_braces_length - 1] == brace_nesting)
 107         extern_C_braces_length--;
 108       brace_nesting--;
 109       goto new_statement;
 110     }
 111   if (token == CPP_LBRACE)
 112     {
 113       brace_nesting++;
 114       goto new_statement;
 115     }
 116   if (token == CPP_EOF)
 117     return 0;
 118   if (token == CPP_SEMICOLON)
 119     goto new_statement;
 120   if (token != CPP_NAME)
 121     goto new_statement;
 122
 123   prev_id_start = 0;
 124   declarator_start = 0;
 125   for (;;)
 126     {
 127       switch (token)
 128         {
 129         case CPP_LPAREN:
 130           /* Looks like this is the start of a formal parameter list.  */
 131           if (prev_id_start)
 132             {
 133               int nesting = 1;
 134               int have_arg_list = 0;
 135               cpp_buffer *fbuf = cpp_file_buffer (pfile);
 136               long func_lineno;
 137               cpp_buf_line_and_col (fbuf, &func_lineno, NULL);
 138               for (;;)
 139                 {
 140                   token = cpp_get_token (pfile);
 141                   if (token == CPP_LPAREN)
 142                     nesting++;
 143                   else if (token == CPP_RPAREN)
 144                     {
 145                       nesting--;
 146                       if (nesting == 0)
 147                         break;
 148                     }
 149                   else if (token == CPP_EOF)
 150                     break;
 151                   else if (token == CPP_NAME || token == CPP_3DOTS)
 152                     have_arg_list = 1;
 153                 }
 154               recognized_function (pfile->token_buffer + prev_id_start,
 155                                    prev_id_end - prev_id_start,
 156                                    (saw_inline ? 'I'
 157                                     : in_extern_C_brace || current_extern_C
 158                                     ? 'F' : 'f'),
 159                                    pfile->token_buffer, prev_id_start,
 160                                    have_arg_list,
 161                                    fbuf->nominal_fname, func_lineno);
 162               token = cpp_get_non_space_token (pfile);
 163               if (token == CPP_LBRACE)
 164                 {
 165                   /* skip body of (normally) inline function */
 166                   skip_to_closing_brace (pfile);
 167                   goto new_statement;
 168                 }
 169               goto maybe_handle_comma;
 170             }
 171           break;
 172         case CPP_OTHER:
 173           if (CPP_WRITTEN (pfile) == start_written + 1
 174               && (CPP_PWRITTEN (pfile)[-1] == '*'
 175                   || CPP_PWRITTEN (pfile)[-1] == '&'))
 176             declarator_start = start_written;
 177           else
 178             goto handle_statement;
 179           break;
 180         case CPP_COMMA:
 181         case CPP_SEMICOLON:
 182           if (prev_id_start && saw_extern)
 183             {
 184               recognized_extern (pfile->token_buffer + prev_id_start,
 185                                  prev_id_end - prev_id_start,
 186                                  pfile->token_buffer,
 187                                  prev_id_start);
 188             }
 189           /* ... fall through ...  */
 190         maybe_handle_comma:
 191           if (token != CPP_COMMA)
 192             goto new_statement;
 193         handle_comma:
 194           /* Handle multiple declarators in a single declaration,
 195              as in:  extern char *strcpy (), *strcat (), ... ; */
 196           if (declarator_start == 0)
 197             declarator_start = prev_id_start;
 198           CPP_SET_WRITTEN (pfile, declarator_start);
 199           break;
 200         case CPP_NAME:
 201           /* "inline" and "extern" are recognized but skipped */
 202           if (strcmp (pfile->token_buffer, "inline") == 0)
 203             {
 204               saw_inline = 1;
 205               CPP_SET_WRITTEN (pfile, start_written);
 206             }
 207           if (strcmp (pfile->token_buffer, "extern") == 0)
 208             {
 209               saw_extern = 1;
 210               CPP_SET_WRITTEN (pfile, start_written);
 211               token = cpp_get_non_space_token (pfile);
 212               if (token == CPP_STRING
 213                   && strcmp (pfile->token_buffer, "\"C\"") == 0)
 214                 {
 215                   CPP_SET_WRITTEN (pfile, start_written);
 216                   current_extern_C = 1;
 217                   token = cpp_get_non_space_token (pfile);
 218                   if (token == CPP_LBRACE)
 219                     {
 220                       brace_nesting++;
 221                       extern_C_braces[extern_C_braces_length++]
 222                         = brace_nesting;
 223                       goto new_statement;
 224                     }
 225                 }
 226               else
 227                 continue;
 228               break;
 229             }
 230           /* This may be the name of a variable or function.  */
 231           prev_id_start = start_written;
 232           prev_id_end = CPP_WRITTEN (pfile);
 233           break;
 234
 235         case CPP_EOF:
 236           return 0;
 237
 238         case CPP_LBRACE:  case CPP_RBRACE:  case CPP_DIRECTIVE:
 239           goto new_statement;  /* handle_statement? */
 240
 241         case CPP_HSPACE:  case CPP_VSPACE:  case CPP_COMMENT:  case CPP_POP:
 242           /* Skip initial white space.  */
 243           if (start_written == 0)
 244             CPP_SET_WRITTEN (pfile, 0);
 245           break;
 246
 247          default:
 248           prev_id_start = 0;
 249         }
 250
 251       start_written = CPP_WRITTEN (pfile);
 252       token = cpp_get_token (pfile);
 253     }
 254 }