1/* depend.c - Handle dependency tracking.
2   Copyright 1997, 1998, 2000, 2001, 2003 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, 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.  */
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 (FILE *, char *);
39static void wrap_output (FILE *, char *, int);
40
41/* Number of columns allowable.  */
42#define MAX_COLUMNS 72
43
44/* Start saving dependencies, to be written to FILENAME.  If this is
45   never called, then dependency tracking is simply skipped.  */
46
47void
48start_dependencies (char *filename)
49{
50  dep_file = filename;
51}
52
53/* Noticed a new filename, so try to register it.  */
54
55void
56register_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
81static int
82quote_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
143static void
144wrap_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
181void
182print_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}
207