gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002, 2007 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., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, 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_file, *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_file = macro_main (sal.symtab->macro_table);
  46   inclusion = macro_lookup_inclusion (main_file, 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_file;
  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_scope *ms;
  87
  88   /* If there's a selected frame, use its PC.  */
  89   if (deprecated_selected_frame)
  90     sal = find_pc_line (get_frame_pc (deprecated_selected_frame), 0);
  91
  92   /* If the target has any registers at all, then use its PC.  Why we
  93      would have registers but no stack, I'm not sure.  */
  94   else if (target_has_registers)
  95     sal = find_pc_line (read_pc (), 0);
  96
  97   /* If all else fails, fall back to the current listing position.  */
  98   else
  99     {
 100       /* Don't call select_source_symtab here.  That can raise an
 101          error if symbols aren't loaded, but GDB calls the expression
 102          evaluator in all sorts of contexts.
 103
 104          For example, commands like `set width' call the expression
 105          evaluator to evaluate their numeric arguments.  If the
 106          current language is C, then that may call this function to
 107          choose a scope for macro expansion.  If you don't have any
 108          symbol files loaded, then get_current_or_default would raise an
 109          error.  But `set width' shouldn't raise an error just because
 110          it can't decide which scope to macro-expand its argument in.  */
 111       struct symtab_and_line cursal =
 112                         get_current_source_symtab_and_line ();
 113
 114       sal.symtab = cursal.symtab;
 115       sal.line = cursal.line;
 116     }
 117
 118   return sal_macro_scope (sal);
 119 }
 120
 121
 122 /* Look up the definition of the macro named NAME in scope at the source
 123    location given by BATON, which must be a pointer to a `struct
 124    macro_scope' structure.  */
 125 struct macro_definition *
 126 standard_macro_lookup (const char *name, void *baton)
 127 {
 128   struct macro_scope *ms = (struct macro_scope *) baton;
 129
 130   return macro_lookup_definition (ms->file, ms->line, name);
 131 }