gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002-2013 Free Software Foundation, Inc.
   3    Contributed by Red Hat, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21
  22 #include "macroscope.h"
  23 #include "symtab.h"
  24 #include "source.h"
  25 #include "target.h"
  26 #include "frame.h"
  27 #include "inferior.h"
  28 #include "complaints.h"
  29
  30 /* A table of user-defined macros.  Unlike the macro tables used for
  31    symtabs, this one uses xmalloc for all its allocation, not an
  32    obstack, and it doesn't bcache anything; it just xmallocs things.  So
  33    it's perfectly possible to remove things from this, or redefine
  34    things.  */
  35 struct macro_table *macro_user_macros;
  36
  37
  38 struct macro_scope *
  39 sal_macro_scope (struct symtab_and_line sal)
  40 {
  41   struct macro_source_file *main_file, *inclusion;
  42   struct macro_scope *ms;
  43
  44   if (! sal.symtab
  45       || ! sal.symtab->macro_table)
  46     return 0;
  47
  48   ms = (struct macro_scope *) xmalloc (sizeof (*ms));
  49
  50   main_file = macro_main (sal.symtab->macro_table);
  51   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
  52
  53   if (inclusion)
  54     {
  55       ms->file = inclusion;
  56       ms->line = sal.line;
  57     }
  58   else
  59     {
  60       /* There are, unfortunately, cases where a compilation unit can
  61          have a symtab for a source file that doesn't appear in the
  62          macro table.  For example, at the moment, Dwarf doesn't have
  63          any way in the .debug_macinfo section to describe the effect
  64          of #line directives, so if you debug a YACC parser you'll get
  65          a macro table which only mentions the .c files generated by
  66          YACC, but symtabs that mention the .y files consumed by YACC.
  67
  68          In the long run, we should extend the Dwarf macro info
  69          representation to handle #line directives, and get GCC to
  70          emit it.
  71
  72          For the time being, though, we'll just treat these as
  73          occurring at the end of the main source file.  */
  74       ms->file = main_file;
  75       ms->line = -1;
  76
  77       complaint (&symfile_complaints,
  78                  _("symtab found for `%s', but that file\n"
  79                  "is not covered in the compilation unit's macro information"),
  80                  symtab_to_filename_for_display (sal.symtab));
  81     }
  82
  83   return ms;
  84 }
  85
  86
  87 struct macro_scope *
  88 user_macro_scope (void)
  89 {
  90   struct macro_scope *ms;
  91
  92   ms = XNEW (struct macro_scope);
  93   ms->file = macro_main (macro_user_macros);
  94   ms->line = -1;
  95   return ms;
  96 }
  97
  98 struct macro_scope *
  99 default_macro_scope (void)
 100 {
 101   struct symtab_and_line sal;
 102   struct macro_scope *ms;
 103   struct frame_info *frame;
 104   CORE_ADDR pc;
 105
 106   /* If there's a selected frame, use its PC.  */
 107   frame = deprecated_safe_get_selected_frame ();
 108   if (frame && get_frame_pc_if_available (frame, &pc))
 109     sal = find_pc_line (pc, 0);
 110
 111   /* Fall back to the current listing position.  */
 112   else
 113     {
 114       /* Don't call select_source_symtab here.  That can raise an
 115          error if symbols aren't loaded, but GDB calls the expression
 116          evaluator in all sorts of contexts.
 117
 118          For example, commands like `set width' call the expression
 119          evaluator to evaluate their numeric arguments.  If the
 120          current language is C, then that may call this function to
 121          choose a scope for macro expansion.  If you don't have any
 122          symbol files loaded, then get_current_or_default would raise an
 123          error.  But `set width' shouldn't raise an error just because
 124          it can't decide which scope to macro-expand its argument in.  */
 125       struct symtab_and_line cursal =
 126                         get_current_source_symtab_and_line ();
 127
 128       sal.symtab = cursal.symtab;
 129       sal.line = cursal.line;
 130     }
 131
 132   ms = sal_macro_scope (sal);
 133   if (! ms)
 134     ms = user_macro_scope ();
 135
 136   return ms;
 137 }
 138
 139
 140 /* Look up the definition of the macro named NAME in scope at the source
 141    location given by BATON, which must be a pointer to a `struct
 142    macro_scope' structure.  */
 143 struct macro_definition *
 144 standard_macro_lookup (const char *name, void *baton)
 145 {
 146   struct macro_scope *ms = (struct macro_scope *) baton;
 147   struct macro_definition *result;
 148
 149   /* Give user-defined macros priority over all others.  */
 150   result = macro_lookup_definition (macro_main (macro_user_macros), -1, name);
 151   if (! result)
 152     result = macro_lookup_definition (ms->file, ms->line, name);
 153   return result;
 154 }
 155
 156 /* Provide a prototype to silence -Wmissing-prototypes.  */
 157 extern initialize_file_ftype _initialize_macroscope;
 158
 159 void
 160 _initialize_macroscope (void)
 161 {
 162   macro_user_macros = new_macro_table (NULL, NULL, NULL);
 163   macro_set_main (macro_user_macros, "<user-defined>");
 164   macro_allow_redefinitions (macro_user_macros);
 165 }