gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002, 2007, 2008 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
  31 struct macro_scope *
  32 sal_macro_scope (struct symtab_and_line sal)
  33 {
  34   struct macro_source_file *main_file, *inclusion;
  35   struct macro_scope *ms;
  36
  37   if (! sal.symtab
  38       || ! sal.symtab->macro_table)
  39     return 0;
  40
  41   ms = (struct macro_scope *) xmalloc (sizeof (*ms));
  42
  43   main_file = macro_main (sal.symtab->macro_table);
  44   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
  45
  46   if (inclusion)
  47     {
  48       ms->file = inclusion;
  49       ms->line = sal.line;
  50     }
  51   else
  52     {
  53       /* There are, unfortunately, cases where a compilation unit can
  54          have a symtab for a source file that doesn't appear in the
  55          macro table.  For example, at the moment, Dwarf doesn't have
  56          any way in the .debug_macinfo section to describe the effect
  57          of #line directives, so if you debug a YACC parser you'll get
  58          a macro table which only mentions the .c files generated by
  59          YACC, but symtabs that mention the .y files consumed by YACC.
  60
  61          In the long run, we should extend the Dwarf macro info
  62          representation to handle #line directives, and get GCC to
  63          emit it.
  64
  65          For the time being, though, we'll just treat these as
  66          occurring at the end of the main source file.  */
  67       ms->file = main_file;
  68       ms->line = -1;
  69
  70       complaint (&symfile_complaints,
  71                  _("symtab found for `%s', but that file\n"
  72                  "is not covered in the compilation unit's macro information"),
  73                  sal.symtab->filename);
  74     }
  75
  76   return ms;
  77 }
  78
  79
  80 struct macro_scope *
  81 default_macro_scope (void)
  82 {
  83   struct symtab_and_line sal;
  84   struct macro_scope *ms;
  85   struct frame_info *frame;
  86
  87   /* If there's a selected frame, use its PC.  */
  88   frame = deprecated_safe_get_selected_frame ();
  89   if (frame)
  90     sal = find_pc_line (get_frame_pc (frame), 0);
  91
  92   /* Fall back to the current listing position.  */
  93   else
  94     {
  95       /* Don't call select_source_symtab here.  That can raise an
  96          error if symbols aren't loaded, but GDB calls the expression
  97          evaluator in all sorts of contexts.
  98
  99          For example, commands like `set width' call the expression
 100          evaluator to evaluate their numeric arguments.  If the
 101          current language is C, then that may call this function to
 102          choose a scope for macro expansion.  If you don't have any
 103          symbol files loaded, then get_current_or_default would raise an
 104          error.  But `set width' shouldn't raise an error just because
 105          it can't decide which scope to macro-expand its argument in.  */
 106       struct symtab_and_line cursal =
 107                         get_current_source_symtab_and_line ();
 108
 109       sal.symtab = cursal.symtab;
 110       sal.line = cursal.line;
 111     }
 112
 113   return sal_macro_scope (sal);
 114 }
 115
 116
 117 /* Look up the definition of the macro named NAME in scope at the source
 118    location given by BATON, which must be a pointer to a `struct
 119    macro_scope' structure.  */
 120 struct macro_definition *
 121 standard_macro_lookup (const char *name, void *baton)
 122 {
 123   struct macro_scope *ms = (struct macro_scope *) baton;
 124
 125   return macro_lookup_definition (ms->file, ms->line, name);
 126 }