gas/depend.c

   1 /* depend.c - Handle dependency tracking.
   2    Copyright 1997, 1998, 2000, 2001 Free Software Foundation, Inc.
   3
   4    This file is part of GAS, the GNU Assembler.
   5
   6    GAS is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    GAS is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GAS; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19    02111-1307, USA.  */
  20
  21 #include "as.h"
  22
  23 /* The file to write to, or NULL if no dependencies being kept.  */
  24 static char * dep_file = NULL;
  25
  26 struct dependency
  27   {
  28     char * file;
  29     struct dependency * next;
  30   };
  31
  32 /* All the files we depend on.  */
  33 static struct dependency * dep_chain = NULL;
  34
  35 /* Current column in output file.  */
  36 static int column = 0;
  37
  38 static int quote_string_for_make PARAMS ((FILE *, char *));
  39 static void wrap_output PARAMS ((FILE *, char *, int));
  40
  41 /* Number of columns allowable.  */
  42 #define MAX_COLUMNS 72
  43 \f
  44 /* Start saving dependencies, to be written to FILENAME.  If this is
  45    never called, then dependency tracking is simply skipped.  */
  46
  47 void
  48 start_dependencies (filename)
  49      char *filename;
  50 {
  51   dep_file = filename;
  52 }
  53
  54 /* Noticed a new filename, so try to register it.  */
  55
  56 void
  57 register_dependency (filename)
  58      char *filename;
  59 {
  60   struct dependency *dep;
  61
  62   if (dep_file == NULL)
  63     return;
  64
  65   for (dep = dep_chain; dep != NULL; dep = dep->next)
  66     {
  67       if (!strcmp (filename, dep->file))
  68         return;
  69     }
  70
  71   dep = (struct dependency *) xmalloc (sizeof (struct dependency));
  72   dep->file = xstrdup (filename);
  73   dep->next = dep_chain;
  74   dep_chain = dep;
  75 }
  76
  77 /* Quote a file name the way `make' wants it, and print it to FILE.
  78    If FILE is NULL, do no printing, but return the length of the
  79    quoted string.
  80
  81    This code is taken from gcc with only minor changes.  */
  82
  83 static int
  84 quote_string_for_make (file, src)
  85      FILE *file;
  86      char *src;
  87 {
  88   char *p = src;
  89   int i = 0;
  90
  91   for (;;)
  92     {
  93       char c = *p++;
  94
  95       switch (c)
  96         {
  97         case '\0':
  98         case ' ':
  99         case '\t':
 100           {
 101             /* GNU make uses a weird quoting scheme for white space.
 102                A space or tab preceded by 2N+1 backslashes represents
 103                N backslashes followed by space; a space or tab
 104                preceded by 2N backslashes represents N backslashes at
 105                the end of a file name; and backslashes in other
 106                contexts should not be doubled.  */
 107             char *q;
 108
 109             for (q = p - 1; src < q && q[-1] == '\\'; q--)
 110               {
 111                 if (file)
 112                   putc ('\\', file);
 113                 i++;
 114               }
 115           }
 116           if (!c)
 117             return i;
 118           if (file)
 119             putc ('\\', file);
 120           i++;
 121           goto ordinary_char;
 122
 123         case '$':
 124           if (file)
 125             putc (c, file);
 126           i++;
 127           /* Fall through.  This can mishandle things like "$(" but
 128              there's no easy fix.  */
 129         default:
 130         ordinary_char:
 131           /* This can mishandle characters in the string "\0\n%*?[\\~";
 132              exactly which chars are mishandled depends on the `make' version.
 133              We know of no portable solution for this;
 134              even GNU make 3.76.1 doesn't solve the problem entirely.
 135              (Also, '\0' is mishandled due to our calling conventions.)  */
 136           if (file)
 137             putc (c, file);
 138           i++;
 139           break;
 140         }
 141     }
 142 }
 143
 144 /* Append some output to the file, keeping track of columns and doing
 145    wrapping as necessary.  */
 146
 147 static void
 148 wrap_output (f, string, spacer)
 149      FILE *f;
 150      char *string;
 151      int spacer;
 152 {
 153   int len = quote_string_for_make (NULL, string);
 154
 155   if (len == 0)
 156     return;
 157
 158   if (column
 159       && (MAX_COLUMNS
 160           - 1 /* spacer */
 161           - 2 /* ` \'   */
 162           < column + len))
 163     {
 164       fprintf (f, " \\\n ");
 165       column = 0;
 166       if (spacer == ' ')
 167         spacer = '\0';
 168     }
 169
 170   if (spacer == ' ')
 171     {
 172       putc (spacer, f);
 173       ++column;
 174     }
 175
 176   quote_string_for_make (f, string);
 177   column += len;
 178
 179   if (spacer == ':')
 180     {
 181       putc (spacer, f);
 182       ++column;
 183     }
 184 }
 185
 186 /* Print dependency file.  */
 187
 188 void
 189 print_dependencies ()
 190 {
 191   FILE *f;
 192   struct dependency *dep;
 193
 194   if (dep_file == NULL)
 195     return;
 196
 197   f = fopen (dep_file, FOPEN_WT);
 198   if (f == NULL)
 199     {
 200       as_warn (_("can't open `%s' for writing"), dep_file);
 201       return;
 202     }
 203
 204   column = 0;
 205   wrap_output (f, out_file_name, ':');
 206   for (dep = dep_chain; dep != NULL; dep = dep->next)
 207     wrap_output (f, dep->file, ' ');
 208
 209   putc ('\n', f);
 210
 211   if (fclose (f))
 212     as_warn (_("can't close `%s'"), dep_file);
 213 }