1/* depend.c - Handle dependency tracking.
2   Copyright (C) 1997-2017 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#include "filenames.h"
23
24/* The file to write to, or NULL if no dependencies being kept.  */
25static char * dep_file = NULL;
26
27struct dependency
28{
29  char * file;
30  struct dependency * next;
31};
32
33/* All the files we depend on.  */
34static struct dependency * dep_chain = NULL;
35
36/* Current column in output file.  */
37static int column = 0;
38
39static int quote_string_for_make (FILE *, const char *);
40static void wrap_output (FILE *, const char *, int);
41
42/* Number of columns allowable.  */
43#define MAX_COLUMNS 72
44
45/* Start saving dependencies, to be written to FILENAME.  If this is
46   never called, then dependency tracking is simply skipped.  */
47
48void
49start_dependencies (char *filename)
50{
51  dep_file = filename;
52}
53
54/* Noticed a new filename, so try to register it.  */
55
56void
57register_dependency (const 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 (!filename_cmp (filename, dep->file))
67	return;
68    }
69
70  dep = XNEW (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 *file, const char *src)
84{
85  const char *p = src;
86  int i = 0;
87
88  for (;;)
89    {
90      char c = *p++;
91
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	    const char *q;
105
106	    for (q = p - 1; src < q && q[-1] == '\\'; q--)
107	      {
108		if (file)
109		  putc ('\\', file);
110		i++;
111	      }
112	  }
113	  if (!c)
114	    return i;
115	  if (file)
116	    putc ('\\', file);
117	  i++;
118	  goto ordinary_char;
119
120	case '$':
121	  if (file)
122	    putc (c, file);
123	  i++;
124	  /* Fall through.  */
125	  /* This can mishandle things like "$(" but there's no easy fix.  */
126	default:
127	ordinary_char:
128	  /* This can mishandle characters in the string "\0\n%*?[\\~";
129	     exactly which chars are mishandled depends on the `make' version.
130	     We know of no portable solution for this;
131	     even GNU make 3.76.1 doesn't solve the problem entirely.
132	     (Also, '\0' is mishandled due to our calling conventions.)  */
133	  if (file)
134	    putc (c, file);
135	  i++;
136	  break;
137	}
138    }
139}
140
141/* Append some output to the file, keeping track of columns and doing
142   wrapping as necessary.  */
143
144static void
145wrap_output (FILE *f, const char *string, int spacer)
146{
147  int len = quote_string_for_make (NULL, string);
148
149  if (len == 0)
150    return;
151
152  if (column
153      && (MAX_COLUMNS
154	  - 1 /* spacer */
155	  - 2 /* ` \'   */
156	  < column + len))
157    {
158      fprintf (f, " \\\n ");
159      column = 0;
160      if (spacer == ' ')
161	spacer = '\0';
162    }
163
164  if (spacer == ' ')
165    {
166      putc (spacer, f);
167      ++column;
168    }
169
170  quote_string_for_make (f, string);
171  column += len;
172
173  if (spacer == ':')
174    {
175      putc (spacer, f);
176      ++column;
177    }
178}
179
180/* Print dependency file.  */
181
182void
183print_dependencies (void)
184{
185  FILE *f;
186  struct dependency *dep;
187
188  if (dep_file == NULL)
189    return;
190
191  f = fopen (dep_file, FOPEN_WT);
192  if (f == NULL)
193    {
194      as_warn (_("can't open `%s' for writing"), dep_file);
195      return;
196    }
197
198  column = 0;
199  wrap_output (f, out_file_name, ':');
200  for (dep = dep_chain; dep != NULL; dep = dep->next)
201    wrap_output (f, dep->file, ' ');
202
203  putc ('\n', f);
204
205  if (fclose (f))
206    as_warn (_("can't close `%s'"), dep_file);
207}
208