1 /* depend.c - Handle dependency tracking.
2 Copyright (C) 1997-2023 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. */
25 static char * dep_file = NULL;
26
27 struct dependency
28 {
29 char * file;
30 struct dependency * next;
31 };
32
33 /* All the files we depend on. */
34 static struct dependency * dep_chain = NULL;
35
36 /* Current column in output file. */
37 static int column = 0;
38
39 static int quote_string_for_make (FILE *, const char *);
40 static 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
48 void
49 start_dependencies (char *filename)
50 {
51 dep_file = filename;
52 }
53
54 /* Noticed a new filename, so try to register it. */
55
56 void
57 register_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
82 static int
83 quote_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
144 static void
145 wrap_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
182 void
183 print_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 }