gcc/file-prefix-map.cc

   1 /* Implementation of file prefix remapping support (-f*-prefix-map options).
   2    Copyright (C) 2017-2024 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   bool canonicalize;
  34   struct file_prefix_map *next;
  35 };
  36
  37 /* Record a file prefix mapping in the specified map.  ARG is the argument to
  38    -f*-prefix-map and must be of the form OLD=NEW.  OPT is the option name
  39    for diagnostics.  */
  40 static void
  41 add_prefix_map (file_prefix_map *&maps, const char *arg, const char *opt)
  42 {
  43   file_prefix_map *map;
  44   const char *p;
  45
  46   /* Note: looking for the last '='. The thinking is we can control the paths
  47      inside our projects but not where the users build them.  */
  48   p = strrchr (arg, '=');
  49   if (!p)
  50     {
  51       error ("invalid argument %qs to %qs", arg, opt);
  52       return;
  53     }
  54   map = XNEW (file_prefix_map);
  55   map->canonicalize = flag_canon_prefix_map;
  56   map->old_prefix = xstrndup (arg, p - arg);
  57   map->old_len = p - arg;
  58   if (map->canonicalize)
  59     {
  60       char *realname = lrealpath (map->old_prefix);
  61       free (const_cast <char *> (map->old_prefix));
  62       map->old_prefix = realname;
  63       map->old_len = strlen (realname);
  64     }
  65   p++;
  66   map->new_prefix = xstrdup (p);
  67   map->new_len = strlen (p);
  68   map->next = maps;
  69   maps = map;
  70 }
  71
  72 /* Perform user-specified mapping of filename prefixes.  Return the
  73    GC-allocated new name corresponding to FILENAME or FILENAME if no
  74    remapping was performed.  */
  75
  76 static const char *
  77 remap_filename (file_prefix_map *maps, const char *filename)
  78 {
  79   file_prefix_map *map;
  80   char *s;
  81   const char *name;
  82   const char *realname = NULL;
  83   size_t name_len;
  84
  85   if (!filename)
  86     return filename;
  87
  88   for (map = maps; map; map = map->next)
  89     if (map->canonicalize)
  90       {
  91         if (realname == NULL)
  92           {
  93             if (lbasename (filename) == filename)
  94               realname = filename;
  95             else
  96               realname = lrealpath (filename);
  97           }
  98         if (filename_ncmp (realname, map->old_prefix, map->old_len) == 0)
  99           break;
 100       }
 101     else if (filename_ncmp (filename, map->old_prefix, map->old_len) == 0)
 102       break;
 103   if (!map)
 104     {
 105       if (realname != filename)
 106         free (const_cast <char *> (realname));
 107       return filename;
 108     }
 109   if (map->canonicalize)
 110     name = realname + map->old_len;
 111   else
 112     name = filename + map->old_len;
 113   name_len = strlen (name) + 1;
 114
 115   s = (char *) ggc_alloc_atomic (name_len + map->new_len);
 116   memcpy (s, map->new_prefix, map->new_len);
 117   memcpy (s + map->new_len, name, name_len);
 118   if (realname != filename)
 119     free (const_cast <char *> (realname));
 120   return s;
 121 }
 122
 123 /* NOTE: if adding another -f*-prefix-map option then don't forget to
 124    ignore it in DW_AT_producer (gen_command_line_string in opts.cc).  */
 125
 126 /* Linked lists of file_prefix_map structures.  */
 127 static file_prefix_map *macro_prefix_maps; /* -fmacro-prefix-map  */
 128 static file_prefix_map *debug_prefix_maps; /* -fdebug-prefix-map  */
 129 static file_prefix_map *profile_prefix_maps; /* -fprofile-prefix-map  */
 130
 131 /* Record a file prefix mapping for -fmacro-prefix-map.  */
 132 void
 133 add_macro_prefix_map (const char *arg)
 134 {
 135   add_prefix_map (macro_prefix_maps, arg, "-fmacro-prefix-map");
 136 }
 137
 138 /* Record a file prefix mapping for -fdebug-prefix-map.  */
 139 void
 140 add_debug_prefix_map (const char *arg)
 141 {
 142   add_prefix_map (debug_prefix_maps, arg, "-fdebug-prefix-map");
 143 }
 144
 145 /* Record a file prefix mapping for all -f*-prefix-map.  */
 146 void
 147 add_file_prefix_map (const char *arg)
 148 {
 149   add_prefix_map (macro_prefix_maps, arg, "-ffile-prefix-map");
 150   add_prefix_map (debug_prefix_maps, arg, "-ffile-prefix-map");
 151   add_prefix_map (profile_prefix_maps, arg, "-ffile-prefix-map");
 152 }
 153
 154 /* Record a file prefix mapping for -fprofile-prefix-map.  */
 155 void
 156 add_profile_prefix_map (const char *arg)
 157 {
 158   add_prefix_map (profile_prefix_maps, arg, "-fprofile-prefix-map");
 159 }
 160
 161 /* Remap using -fmacro-prefix-map.  Return the GC-allocated new name
 162    corresponding to FILENAME or FILENAME if no remapping was performed.  */
 163 const char *
 164 remap_macro_filename (const char *filename)
 165 {
 166   return remap_filename (macro_prefix_maps, filename);
 167 }
 168
 169 /* Remap using -fdebug-prefix-map.  Return the GC-allocated new name
 170    corresponding to FILENAME or FILENAME if no remapping was performed.  */
 171 const char *
 172 remap_debug_filename (const char *filename)
 173 {
 174   return remap_filename (debug_prefix_maps, filename);
 175 }
 176
 177 /* Remap using -fprofile-prefix-map.  Return the GC-allocated new name
 178    corresponding to FILENAME or FILENAME if no remapping was performed.  */
 179 const char *
 180 remap_profile_filename (const char *filename)
 181 {
 182   return remap_filename (profile_prefix_maps, filename);
 183 }