gcc/file-prefix-map.c

   1 /* Implementation of file prefix remapping support (-f*-prefix-map options).
   2    Copyright (C) 2017-2021 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published by the
   6    Free Software Foundation; either version 3, or (at your option) any
   7    later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; see the file COPYING3.  If not see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include "config.h"
  19 #include "system.h"
  20 #include "coretypes.h"
  21 #include "diagnostic.h"
  22 #include "file-prefix-map.h"
  23
  24 /* Structure recording the mapping from source file and directory names at
  25    compile time to those to be embedded in the compilation result (debug
  26    information, the __FILE__ macro expansion, etc).  */
  27 struct file_prefix_map
  28 {
  29   const char *old_prefix;
  30   const char *new_prefix;
  31   size_t old_len;
  32   size_t new_len;
  33   struct file_prefix_map *next;
  34 };
  35
  36 /* Record a file prefix mapping in the specified map.  ARG is the argument to
  37    -f*-prefix-map and must be of the form OLD=NEW.  OPT is the option name
  38    for diagnostics.  */
  39 static void
  40 add_prefix_map (file_prefix_map *&maps, const char *arg, const char *opt)
  41 {
  42   file_prefix_map *map;
  43   const char *p;
  44
  45   /* Note: looking for the last '='. The thinking is we can control the paths
  46      inside our projects but not where the users build them.  */
  47   p = strrchr (arg, '=');
  48   if (!p)
  49     {
  50       error ("invalid argument %qs to %qs", arg, opt);
  51       return;
  52     }
  53   map = XNEW (file_prefix_map);
  54   map->old_prefix = xstrndup (arg, p - arg);
  55   map->old_len = p - arg;
  56   p++;
  57   map->new_prefix = xstrdup (p);
  58   map->new_len = strlen (p);
  59   map->next = maps;
  60   maps = map;
  61 }
  62
  63 /* Perform user-specified mapping of filename prefixes.  Return the
  64    GC-allocated new name corresponding to FILENAME or FILENAME if no
  65    remapping was performed.  */
  66
  67 static const char *
  68 remap_filename (file_prefix_map *maps, const char *filename)
  69 {
  70   file_prefix_map *map;
  71   char *s;
  72   const char *name;
  73   size_t name_len;
  74
  75   for (map = maps; map; map = map->next)
  76     if (filename_ncmp (filename, map->old_prefix, map->old_len) == 0)
  77       break;
  78   if (!map)
  79     return filename;
  80   name = filename + map->old_len;
  81   name_len = strlen (name) + 1;
  82
  83   s = (char *) ggc_alloc_atomic (name_len + map->new_len);
  84   memcpy (s, map->new_prefix, map->new_len);
  85   memcpy (s + map->new_len, name, name_len);
  86   return s;
  87 }
  88
  89 /* NOTE: if adding another -f*-prefix-map option then don't forget to
  90    ignore it in DW_AT_producer (dwarf2out.c).  */
  91
  92 /* Linked lists of file_prefix_map structures.  */
  93 static file_prefix_map *macro_prefix_maps; /* -fmacro-prefix-map  */
  94 static file_prefix_map *debug_prefix_maps; /* -fdebug-prefix-map  */
  95
  96 /* Record a file prefix mapping for -fmacro-prefix-map.  */
  97 void
  98 add_macro_prefix_map (const char *arg)
  99 {
 100   add_prefix_map (macro_prefix_maps, arg, "-fmacro-prefix-map");
 101 }
 102
 103 /* Record a file prefix mapping for -fdebug-prefix-map.  */
 104 void
 105 add_debug_prefix_map (const char *arg)
 106 {
 107   add_prefix_map (debug_prefix_maps, arg, "-fdebug-prefix-map");
 108 }
 109
 110 /* Record a file prefix mapping for all -f*-prefix-map.  */
 111 void
 112 add_file_prefix_map (const char *arg)
 113 {
 114   add_prefix_map (macro_prefix_maps, arg, "-ffile-prefix-map");
 115   add_prefix_map (debug_prefix_maps, arg, "-ffile-prefix-map");
 116 }
 117
 118 /* Remap using -fmacro-prefix-map.  Return the GC-allocated new name
 119    corresponding to FILENAME or FILENAME if no remapping was performed.  */
 120 const char *
 121 remap_macro_filename (const char *filename)
 122 {
 123   return remap_filename (macro_prefix_maps, filename);
 124 }
 125
 126 /* Remap using -fdebug-prefix-map.  Return the GC-allocated new name
 127    corresponding to FILENAME or FILENAME if no remapping was performed.  */
 128 const char *
 129 remap_debug_filename (const char *filename)
 130 {
 131   return remap_filename (debug_prefix_maps, filename);
 132 }