gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright 2002 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 2 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, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23
  24 #include "macroscope.h"
  25 #include "symtab.h"
  26 #include "target.h"
  27 #include "frame.h"
  28 #include "inferior.h"
  29
  30
  31 struct macro_scope *
  32 sal_macro_scope (struct symtab_and_line sal)
  33 {
  34   struct macro_source_file *main;
  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 = macro_main (sal.symtab->macro_table);
  44   ms->file = macro_lookup_inclusion (main, sal.symtab->filename);
  45
  46   if (! ms->file)
  47     internal_error
  48       (__FILE__, __LINE__,
  49        "\n"
  50        "the symtab `%s' refers to a preprocessor macro table which doesn't\n"
  51        "have any record of processing a file by that name.\n",
  52        sal.symtab->filename);
  53
  54   ms->line = sal.line;
  55
  56   return ms;
  57 }
  58
  59
  60 struct macro_scope *
  61 default_macro_scope ()
  62 {
  63   struct symtab_and_line sal;
  64   struct macro_source_file *main;
  65   struct macro_scope *ms;
  66
  67   /* If there's a selected frame, use its PC.  */
  68   if (selected_frame)
  69     sal = find_pc_line (selected_frame->pc, 0);
  70
  71   /* If the target has any registers at all, then use its PC.  Why we
  72      would have registers but no stack, I'm not sure.  */
  73   else if (target_has_registers)
  74     sal = find_pc_line (read_pc (), 0);
  75
  76   /* If all else fails, fall back to the current listing position.  */
  77   else
  78     {
  79       /* Don't call select_source_symtab here.  That can raise an
  80          error if symbols aren't loaded, but GDB calls the expression
  81          evaluator in all sorts of contexts.
  82
  83          For example, commands like `set width' call the expression
  84          evaluator to evaluate their numeric arguments.  If the
  85          current language is C, then that may call this function to
  86          choose a scope for macro expansion.  If you don't have any
  87          symbol files loaded, then select_source_symtab will raise an
  88          error.  But `set width' shouldn't raise an error just because
  89          it can't decide which scope to macro-expand its argument in.  */
  90       sal.symtab = current_source_symtab;
  91       sal.line = current_source_line;
  92     }
  93
  94   return sal_macro_scope (sal);
  95 }
  96
  97
  98 /* Look up the definition of the macro named NAME in scope at the source
  99    location given by BATON, which must be a pointer to a `struct
 100    macro_scope' structure.  */
 101 struct macro_definition *
 102 standard_macro_lookup (const char *name, void *baton)
 103 {
 104   struct macro_scope *ms = (struct macro_scope *) baton;
 105
 106   return macro_lookup_definition (ms->file, ms->line, name);
 107 }