depend.c revision 38889 
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.  */
24static char *dep_file = NULL;
25
26struct dependency
27{
28  char *file;
29  struct dependency *next;
30};
31
32/* All the files we depend on.  */
33static struct dependency *dep_chain = NULL;
34
35/* Current column in output file.  */
36static int column = 0;
37
38static int quote_string_for_make PARAMS ((FILE *, char *));
39static void wrap_output PARAMS ((FILE *, char *, int));
40
41/* Number of columns allowable.  */
42#define MAX_COLUMNS 72
43
44
45
46/* Start saving dependencies, to be written to FILENAME.  If this is
47   never called, then dependency tracking is simply skipped.  */
48
49void
50start_dependencies (filename)
51     char *filename;
52{
53  dep_file = filename;
54}
55
56/* Noticed a new filename, so try to register it.  */
57
58void
59register_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
85static int
86quote_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
146static void
147wrap_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
183void
184print_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}
209