1 /* depend.c - Handle dependency tracking. 2 Copyright (C) 1997-2016 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 '$': 121 if (file) 122 putc (c, file); 123 i++; 124 /* Fall through. This can mishandle things like "$(" but 125 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 } 208