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