gas/depend.c

   1 /* depend.c - Handle dependency tracking.
   2    Copyright (C) 1997, 1998 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   char *file;
  28   struct dependency *next;
  29 };
  30
  31 /* All the files we depend on.  */
  32 static struct dependency *dep_chain = NULL;
  33
  34 /* Current column in output file.  */
  35 static int column = 0;
  36
  37 static int quote_string_for_make PARAMS ((FILE *, char *));
  38 static void wrap_output PARAMS ((FILE *, char *, int));
  39
  40 /* Number of columns allowable.  */
  41 #define MAX_COLUMNS 72
  42 \f
  43 /* Start saving dependencies, to be written to FILENAME.  If this is
  44    never called, then dependency tracking is simply skipped.  */
  45
  46 void
  47 start_dependencies (filename)
  48      char *filename;
  49 {
  50   dep_file = filename;
  51 }
  52
  53 /* Noticed a new filename, so try to register it.  */
  54
  55 void
  56 register_dependency (filename)
  57      char *filename;
  58 {
  59   struct dependency *dep;
  60
  61   if (dep_file == NULL)
  62     return;
  63
  64   for (dep = dep_chain; dep != NULL; dep = dep->next)
  65     {
  66       if (!strcmp (filename, dep->file))
  67         return;
  68     }
  69
  70   dep = (struct dependency *) xmalloc (sizeof (struct dependency));
  71   dep->file = xstrdup (filename);
  72   dep->next = dep_chain;
  73   dep_chain = dep;
  74 }
  75
  76 /* Quote a file name the way `make' wants it, and print it to FILE.
  77    If FILE is NULL, do no printing, but return the length of the
  78    quoted string.
  79
  80    This code is taken from gcc with only minor changes.  */
  81
  82 static int
  83 quote_string_for_make (file, src)
  84      FILE *file;
  85      char *src;
  86 {
  87   char *p = src;
  88   int i = 0;
  89   for (;;)
  90     {
  91       char c = *p++;
  92       switch (c)
  93         {
  94         case '\0':
  95         case ' ':
  96         case '\t':
  97           {
  98             /* GNU make uses a weird quoting scheme for white space.
  99                A space or tab preceded by 2N+1 backslashes represents
 100                N backslashes followed by space; a space or tab
 101                preceded by 2N backslashes represents N backslashes at
 102                the end of a file name; and backslashes in other
 103                contexts should not be doubled.  */
 104             char *q;
 105             for (q = p - 1; src < q && q[-1] == '\\'; q--)
 106               {
 107                 if (file)
 108                   putc ('\\', file);
 109                 i++;
 110               }
 111           }
 112           if (!c)
 113             return i;
 114           if (file)
 115             putc ('\\', file);
 116           i++;
 117           goto ordinary_char;
 118
 119         case '$':
 120           if (file)
 121             putc (c, file);
 122           i++;
 123           /* Fall through.  This can mishandle things like "$(" but
 124              there's no easy fix.  */
 125         default:
 126         ordinary_char:
 127           /* This can mishandle characters in the string "\0\n%*?[\\~";
 128              exactly which chars are mishandled depends on the `make' version.
 129              We know of no portable solution for this;
 130              even GNU make 3.76.1 doesn't solve the problem entirely.
 131              (Also, '\0' is mishandled due to our calling conventions.)  */
 132           if (file)
 133             putc (c, file);
 134           i++;
 135           break;
 136         }
 137     }
 138 }
 139
 140 /* Append some output to the file, keeping track of columns and doing
 141    wrapping as necessary.  */
 142
 143 static void
 144 wrap_output (f, string, spacer)
 145      FILE *f;
 146      char *string;
 147      int spacer;
 148 {
 149   int len = quote_string_for_make (NULL, string);
 150
 151   if (len == 0)
 152     return;
 153
 154   if (column
 155       && (MAX_COLUMNS
 156           - 1 /* spacer */
 157           - 2 /* ` \'   */
 158           < column + len))
 159     {
 160       fprintf (f, " \\\n ");
 161       column = 0;
 162       if (spacer == ' ')
 163         spacer = '\0';
 164     }
 165
 166   if (spacer == ' ')
 167     {
 168       putc (spacer, f);
 169       ++column;
 170     }
 171
 172   quote_string_for_make (f, string);
 173   column += len;
 174
 175   if (spacer == ':')
 176     {
 177       putc (spacer, f);
 178       ++column;
 179     }
 180 }
 181
 182 /* Print dependency file.  */
 183
 184 void
 185 print_dependencies ()
 186 {
 187   FILE *f;
 188   struct dependency *dep;
 189
 190   if (dep_file == NULL)
 191     return;
 192
 193   f = fopen (dep_file, "w");
 194   if (f == NULL)
 195     {
 196       as_warn (_("Can't open `%s' for writing"), dep_file);
 197       return;
 198     }
 199
 200   column = 0;
 201   wrap_output (f, out_file_name, ':');
 202   for (dep = dep_chain; dep != NULL; dep = dep->next)
 203     wrap_output (f, dep->file, ' ');
 204
 205   putc ('\n', f);
 206
 207   if (fclose (f))
 208     as_warn (_("Can't close `%s'"), dep_file);
 209 }