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 {
  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   for (;;)
  91     {
  92       char c = *p++;
  93       switch (c)
  94         {
  95         case '\0':
  96         case ' ':
  97         case '\t':
  98           {
  99             /* GNU make uses a weird quoting scheme for white space.
 100                A space or tab preceded by 2N+1 backslashes represents
 101                N backslashes followed by space; a space or tab
 102                preceded by 2N backslashes represents N backslashes at
 103                the end of a file name; and backslashes in other
 104                contexts should not be doubled.  */
 105             char *q;
 106             for (q = p - 1; src < q && q[-1] == '\\'; q--)
 107               {
 108                 if (file)
 109                   putc ('\\', file);
 110                 i++;
 111               }
 112           }
 113           if (!c)
 114             return i;
 115           if (file)
 116             putc ('\\', file);
 117           i++;
 118           goto ordinary_char;
 119
 120         case '$':
 121           if (file)
 122             putc (c, file);
 123           i++;
 124           /* Fall through.  This can mishandle things like "$(" but
 125              there's no easy fix.  */
 126         default:
 127         ordinary_char:
 128           /* This can mishandle characters in the string "\0\n%*?[\\~";
 129              exactly which chars are mishandled depends on the `make' version.
 130              We know of no portable solution for this;
 131              even GNU make 3.76.1 doesn't solve the problem entirely.
 132              (Also, '\0' is mishandled due to our calling conventions.)  */
 133           if (file)
 134             putc (c, file);
 135           i++;
 136           break;
 137         }
 138     }
 139 }
 140
 141 /* Append some output to the file, keeping track of columns and doing
 142    wrapping as necessary.  */
 143
 144 static void
 145 wrap_output (f, string, spacer)
 146      FILE *f;
 147      char *string;
 148      int spacer;
 149 {
 150   int len = quote_string_for_make (NULL, string);
 151
 152   if (len == 0)
 153     return;
 154
 155   if (column
 156       && (MAX_COLUMNS
 157           - 1 /* spacer */
 158           - 2 /* ` \'   */
 159           < column + len))
 160     {
 161       fprintf (f, " \\\n ");
 162       column = 0;
 163       if (spacer == ' ')
 164         spacer = '\0';
 165     }
 166
 167   if (spacer == ' ')
 168     {
 169       putc (spacer, f);
 170       ++column;
 171     }
 172
 173   quote_string_for_make (f, string);
 174   column += len;
 175
 176   if (spacer == ':')
 177     {
 178       putc (spacer, f);
 179       ++column;
 180     }
 181 }
 182
 183 /* Print dependency file.  */
 184
 185 void
 186 print_dependencies ()
 187 {
 188   FILE *f;
 189   struct dependency *dep;
 190
 191   if (dep_file == NULL)
 192     return;
 193
 194   f = fopen (dep_file, "w");
 195   if (f == NULL)
 196     {
 197       as_warn (_("Can't open `%s' for writing"), dep_file);
 198       return;
 199     }
 200
 201   column = 0;
 202   wrap_output (f, out_file_name, ':');
 203   for (dep = dep_chain; dep != NULL; dep = dep->next)
 204     wrap_output (f, dep->file, ' ');
 205
 206   putc ('\n', f);
 207
 208   if (fclose (f))
 209     as_warn (_("Can't close `%s'"), dep_file);
 210 }