gas/depend.c

   1 /* depend.c - Handle dependency tracking.
   2    Copyright 1997, 1998, 2000, 2001, 2003, 2004, 2005, 2007
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #include "as.h"
  23 #include "filenames.h"
  24
  25 /* The file to write to, or NULL if no dependencies being kept.  */
  26 static char * dep_file = NULL;
  27
  28 struct dependency
  29   {
  30     char * file;
  31     struct dependency * next;
  32   };
  33
  34 /* All the files we depend on.  */
  35 static struct dependency * dep_chain = NULL;
  36
  37 /* Current column in output file.  */
  38 static int column = 0;
  39
  40 static int quote_string_for_make (FILE *, char *);
  41 static void wrap_output (FILE *, char *, int);
  42
  43 /* Number of columns allowable.  */
  44 #define MAX_COLUMNS 72
  45 \f
  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 (char *filename)
  51 {
  52   dep_file = filename;
  53 }
  54
  55 /* Noticed a new filename, so try to register it.  */
  56
  57 void
  58 register_dependency (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 (!filename_cmp (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 *file, char *src)
  85 {
  86   char *p = src;
  87   int i = 0;
  88
  89   for (;;)
  90     {
  91       char c = *p++;
  92
  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
 107             for (q = p - 1; src < q && q[-1] == '\\'; q--)
 108               {
 109                 if (file)
 110                   putc ('\\', file);
 111                 i++;
 112               }
 113           }
 114           if (!c)
 115             return i;
 116           if (file)
 117             putc ('\\', file);
 118           i++;
 119           goto ordinary_char;
 120
 121         case '$':
 122           if (file)
 123             putc (c, file);
 124           i++;
 125           /* Fall through.  This can mishandle things like "$(" but
 126              there's no easy fix.  */
 127         default:
 128         ordinary_char:
 129           /* This can mishandle characters in the string "\0\n%*?[\\~";
 130              exactly which chars are mishandled depends on the `make' version.
 131              We know of no portable solution for this;
 132              even GNU make 3.76.1 doesn't solve the problem entirely.
 133              (Also, '\0' is mishandled due to our calling conventions.)  */
 134           if (file)
 135             putc (c, file);
 136           i++;
 137           break;
 138         }
 139     }
 140 }
 141
 142 /* Append some output to the file, keeping track of columns and doing
 143    wrapping as necessary.  */
 144
 145 static void
 146 wrap_output (FILE *f, char *string, int spacer)
 147 {
 148   int len = quote_string_for_make (NULL, string);
 149
 150   if (len == 0)
 151     return;
 152
 153   if (column
 154       && (MAX_COLUMNS
 155           - 1 /* spacer */
 156           - 2 /* ` \'   */
 157           < 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 (void)
 185 {
 186   FILE *f;
 187   struct dependency *dep;
 188
 189   if (dep_file == NULL)
 190     return;
 191
 192   f = fopen (dep_file, FOPEN_WT);
 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 }