depend.c revision 77298 
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  char *file;
28  struct dependency *next;
29};
30
31/* All the files we depend on.  */
32static struct dependency *dep_chain = NULL;
33
34/* Current column in output file.  */
35static int column = 0;
36
37static int quote_string_for_make PARAMS ((FILE *, char *));
38static void wrap_output PARAMS ((FILE *, char *, int));
39
40/* Number of columns allowable.  */
41#define MAX_COLUMNS 72
42
43/* Start saving dependencies, to be written to FILENAME.  If this is
44   never called, then dependency tracking is simply skipped.  */
45
46void
47start_dependencies (filename)
48     char *filename;
49{
50  dep_file = filename;
51}
52
53/* Noticed a new filename, so try to register it.  */
54
55void
56register_dependency (filename)
57     char *filename;
58{
59  struct dependency *dep;
60
61  if (dep_file == NULL)
62    return;
63
64  for (dep = dep_chain; dep != NULL; dep = dep->next)
65    {
66      if (!strcmp (filename, dep->file))
67	return;
68    }
69
70  dep = (struct dependency *) xmalloc (sizeof (struct dependency));
71  dep->file = xstrdup (filename);
72  dep->next = dep_chain;
73  dep_chain = dep;
74}
75
76/* Quote a file name the way `make' wants it, and print it to FILE.
77   If FILE is NULL, do no printing, but return the length of the
78   quoted string.
79
80   This code is taken from gcc with only minor changes.  */
81
82static int
83quote_string_for_make (file, src)
84     FILE *file;
85     char *src;
86{
87  char *p = src;
88  int i = 0;
89  for (;;)
90    {
91      char c = *p++;
92      switch (c)
93	{
94	case '\0':
95	case ' ':
96	case '\t':
97	  {
98	    /* GNU make uses a weird quoting scheme for white space.
99	       A space or tab preceded by 2N+1 backslashes represents
100	       N backslashes followed by space; a space or tab
101	       preceded by 2N backslashes represents N backslashes at
102	       the end of a file name; and backslashes in other
103	       contexts should not be doubled.  */
104	    char *q;
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
143static void
144wrap_output (f, string, spacer)
145     FILE *f;
146     char *string;
147     int spacer;
148{
149  int len = quote_string_for_make (NULL, string);
150
151  if (len == 0)
152    return;
153
154  if (column
155      && (MAX_COLUMNS
156	  - 1 /* spacer */
157	  - 2 /* ` \'   */
158	  < column + len))
159    {
160      fprintf (f, " \\\n ");
161      column = 0;
162      if (spacer == ' ')
163	spacer = '\0';
164    }
165
166  if (spacer == ' ')
167    {
168      putc (spacer, f);
169      ++column;
170    }
171
172  quote_string_for_make (f, string);
173  column += len;
174
175  if (spacer == ':')
176    {
177      putc (spacer, f);
178      ++column;
179    }
180}
181
182/* Print dependency file.  */
183
184void
185print_dependencies ()
186{
187  FILE *f;
188  struct dependency *dep;
189
190  if (dep_file == NULL)
191    return;
192
193  f = fopen (dep_file, "w");
194  if (f == NULL)
195    {
196      as_warn (_("Can't open `%s' for writing"), dep_file);
197      return;
198    }
199
200  column = 0;
201  wrap_output (f, out_file_name, ':');
202  for (dep = dep_chain; dep != NULL; dep = dep->next)
203    wrap_output (f, dep->file, ' ');
204
205  putc ('\n', f);
206
207  if (fclose (f))
208    as_warn (_("Can't close `%s'"), dep_file);
209}
210