gas/depend.c

   1 /* depend.c - Handle dependency tracking.
   2    Copyright 1997, 1998, 2000, 2001, 2003, 2007 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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA
  19    02110-1301, 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 (FILE *, char *);
  39 static void wrap_output (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 (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 (char *filename)
  57 {
  58   struct dependency *dep;
  59
  60   if (dep_file == NULL)
  61     return;
  62
  63   for (dep = dep_chain; dep != NULL; dep = dep->next)
  64     {
  65       if (!strcmp (filename, dep->file))
  66         return;
  67     }
  68
  69   dep = (struct dependency *) xmalloc (sizeof (struct dependency));
  70   dep->file = xstrdup (filename);
  71   dep->next = dep_chain;
  72   dep_chain = dep;
  73 }
  74
  75 /* Quote a file name the way `make' wants it, and print it to FILE.
  76    If FILE is NULL, do no printing, but return the length of the
  77    quoted string.
  78
  79    This code is taken from gcc with only minor changes.  */
  80
  81 static int
  82 quote_string_for_make (FILE *file, char *src)
  83 {
  84   char *p = src;
  85   int i = 0;
  86
  87   for (;;)
  88     {
  89       char c = *p++;
  90
  91       switch (c)
  92         {
  93         case '\0':
  94         case ' ':
  95         case '\t':
  96           {
  97             /* GNU make uses a weird quoting scheme for white space.
  98                A space or tab preceded by 2N+1 backslashes represents
  99                N backslashes followed by space; a space or tab
 100                preceded by 2N backslashes represents N backslashes at
 101                the end of a file name; and backslashes in other
 102                contexts should not be doubled.  */
 103             char *q;
 104
 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 (FILE *f, char *string, int spacer)
 145 {
 146   int len = quote_string_for_make (NULL, string);
 147
 148   if (len == 0)
 149     return;
 150
 151   if (column
 152       && (MAX_COLUMNS
 153           - 1 /* spacer */
 154           - 2 /* ` \'   */
 155           < column + len))
 156     {
 157       fprintf (f, " \\\n ");
 158       column = 0;
 159       if (spacer == ' ')
 160         spacer = '\0';
 161     }
 162
 163   if (spacer == ' ')
 164     {
 165       putc (spacer, f);
 166       ++column;
 167     }
 168
 169   quote_string_for_make (f, string);
 170   column += len;
 171
 172   if (spacer == ':')
 173     {
 174       putc (spacer, f);
 175       ++column;
 176     }
 177 }
 178
 179 /* Print dependency file.  */
 180
 181 void
 182 print_dependencies (void)
 183 {
 184   FILE *f;
 185   struct dependency *dep;
 186
 187   if (dep_file == NULL)
 188     return;
 189
 190   f = fopen (dep_file, FOPEN_WT);
 191   if (f == NULL)
 192     {
 193       as_warn (_("can't open `%s' for writing"), dep_file);
 194       return;
 195     }
 196
 197   column = 0;
 198   wrap_output (f, out_file_name, ':');
 199   for (dep = dep_chain; dep != NULL; dep = dep->next)
 200     wrap_output (f, dep->file, ' ');
 201
 202   putc ('\n', f);
 203
 204   if (fclose (f))
 205     as_warn (_("can't close `%s'"), dep_file);
 206 }