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 "source.h"
  27 #include "target.h"
  28 #include "frame.h"
  29 #include "inferior.h"
  30 #include "complaints.h"
  31
  32
  33 struct macro_scope *
  34 sal_macro_scope (struct symtab_and_line sal)
  35 {
  36   struct macro_source_file *main, *inclusion;
  37   struct macro_scope *ms;
  38
  39   if (! sal.symtab
  40       || ! sal.symtab->macro_table)
  41     return 0;
  42
  43   ms = (struct macro_scope *) xmalloc (sizeof (*ms));
  44
  45   main = macro_main (sal.symtab->macro_table);
  46   inclusion = macro_lookup_inclusion (main, sal.symtab->filename);
  47
  48   if (inclusion)
  49     {
  50       ms->file = inclusion;
  51       ms->line = sal.line;
  52     }
  53   else
  54     {
  55       /* There are, unfortunately, cases where a compilation unit can
  56          have a symtab for a source file that doesn't appear in the
  57          macro table.  For example, at the moment, Dwarf doesn't have
  58          any way in the .debug_macinfo section to describe the effect
  59          of #line directives, so if you debug a YACC parser you'll get
  60          a macro table which only mentions the .c files generated by
  61          YACC, but symtabs that mention the .y files consumed by YACC.
  62
  63          In the long run, we should extend the Dwarf macro info
  64          representation to handle #line directives, and get GCC to
  65          emit it.
  66
  67          For the time being, though, we'll just treat these as
  68          occurring at the end of the main source file.  */
  69       ms->file = main;
  70       ms->line = -1;
  71
  72       complaint (&symfile_complaints,
  73                  "symtab found for `%s', but that file\n"
  74                  "is not covered in the compilation unit's macro information",
  75                  sal.symtab->filename);
  76     }
  77
  78   return ms;
  79 }
  80
  81
  82 struct macro_scope *
  83 default_macro_scope (void)
  84 {
  85   struct symtab_and_line sal;
  86   struct macro_source_file *main;
  87   struct macro_scope *ms;
  88
  89   /* If there's a selected frame, use its PC.  */
  90   if (deprecated_selected_frame)
  91     sal = find_pc_line (get_frame_pc (deprecated_selected_frame), 0);
  92
  93   /* If the target has any registers at all, then use its PC.  Why we
  94      would have registers but no stack, I'm not sure.  */
  95   else if (target_has_registers)
  96     sal = find_pc_line (read_pc (), 0);
  97
  98   /* If all else fails, fall back to the current listing position.  */
  99   else
 100     {
 101       /* Don't call select_source_symtab here.  That can raise an
 102          error if symbols aren't loaded, but GDB calls the expression
 103          evaluator in all sorts of contexts.
 104
 105          For example, commands like `set width' call the expression
 106          evaluator to evaluate their numeric arguments.  If the
 107          current language is C, then that may call this function to
 108          choose a scope for macro expansion.  If you don't have any
 109          symbol files loaded, then get_current_or_default would raise an
 110          error.  But `set width' shouldn't raise an error just because
 111          it can't decide which scope to macro-expand its argument in.  */
 112       struct symtab_and_line cursal =
 113                         get_current_source_symtab_and_line ();
 114
 115       sal.symtab = cursal.symtab;
 116       sal.line = cursal.line;
 117     }
 118
 119   return sal_macro_scope (sal);
 120 }
 121
 122
 123 /* Look up the definition of the macro named NAME in scope at the source
 124    location given by BATON, which must be a pointer to a `struct
 125    macro_scope' structure.  */
 126 struct macro_definition *
 127 standard_macro_lookup (const char *name, void *baton)
 128 {
 129   struct macro_scope *ms = (struct macro_scope *) baton;
 130
 131   return macro_lookup_definition (ms->file, ms->line, name);
 132 }