gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002, 2007, 2008, 2009, 2010, 2011
   3    Free Software Foundation, Inc.
   4    Contributed by Red Hat, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22
  23 #include "macroscope.h"
  24 #include "symtab.h"
  25 #include "source.h"
  26 #include "target.h"
  27 #include "frame.h"
  28 #include "inferior.h"
  29 #include "complaints.h"
  30
  31 /* A table of user-defined macros.  Unlike the macro tables used for
  32    symtabs, this one uses xmalloc for all its allocation, not an
  33    obstack, and it doesn't bcache anything; it just xmallocs things.  So
  34    it's perfectly possible to remove things from this, or redefine
  35    things.  */
  36 struct macro_table *macro_user_macros;
  37
  38
  39 struct macro_scope *
  40 sal_macro_scope (struct symtab_and_line sal)
  41 {
  42   struct macro_source_file *main_file, *inclusion;
  43   struct macro_scope *ms;
  44
  45   if (! sal.symtab
  46       || ! sal.symtab->macro_table)
  47     return 0;
  48
  49   ms = (struct macro_scope *) xmalloc (sizeof (*ms));
  50
  51   main_file = macro_main (sal.symtab->macro_table);
  52   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
  53
  54   if (inclusion)
  55     {
  56       ms->file = inclusion;
  57       ms->line = sal.line;
  58     }
  59   else
  60     {
  61       /* There are, unfortunately, cases where a compilation unit can
  62          have a symtab for a source file that doesn't appear in the
  63          macro table.  For example, at the moment, Dwarf doesn't have
  64          any way in the .debug_macinfo section to describe the effect
  65          of #line directives, so if you debug a YACC parser you'll get
  66          a macro table which only mentions the .c files generated by
  67          YACC, but symtabs that mention the .y files consumed by YACC.
  68
  69          In the long run, we should extend the Dwarf macro info
  70          representation to handle #line directives, and get GCC to
  71          emit it.
  72
  73          For the time being, though, we'll just treat these as
  74          occurring at the end of the main source file.  */
  75       ms->file = main_file;
  76       ms->line = -1;
  77
  78       complaint (&symfile_complaints,
  79                  _("symtab found for `%s', but that file\n"
  80                  "is not covered in the compilation unit's macro information"),
  81                  sal.symtab->filename);
  82     }
  83
  84   return ms;
  85 }
  86
  87
  88 struct macro_scope *
  89 user_macro_scope (void)
  90 {
  91   struct macro_scope *ms;
  92
  93   ms = XNEW (struct macro_scope);
  94   ms->file = macro_main (macro_user_macros);
  95   ms->line = -1;
  96   return ms;
  97 }
  98
  99 struct macro_scope *
 100 default_macro_scope (void)
 101 {
 102   struct symtab_and_line sal;
 103   struct macro_scope *ms;
 104   struct frame_info *frame;
 105   CORE_ADDR pc;
 106
 107   /* If there's a selected frame, use its PC.  */
 108   frame = deprecated_safe_get_selected_frame ();
 109   if (frame && get_frame_pc_if_available (frame, &pc))
 110     sal = find_pc_line (pc, 0);
 111
 112   /* Fall back to the current listing position.  */
 113   else
 114     {
 115       /* Don't call select_source_symtab here.  That can raise an
 116          error if symbols aren't loaded, but GDB calls the expression
 117          evaluator in all sorts of contexts.
 118
 119          For example, commands like `set width' call the expression
 120          evaluator to evaluate their numeric arguments.  If the
 121          current language is C, then that may call this function to
 122          choose a scope for macro expansion.  If you don't have any
 123          symbol files loaded, then get_current_or_default would raise an
 124          error.  But `set width' shouldn't raise an error just because
 125          it can't decide which scope to macro-expand its argument in.  */
 126       struct symtab_and_line cursal =
 127                         get_current_source_symtab_and_line ();
 128
 129       sal.symtab = cursal.symtab;
 130       sal.line = cursal.line;
 131     }
 132
 133   ms = sal_macro_scope (sal);
 134   if (! ms)
 135     ms = user_macro_scope ();
 136
 137   return ms;
 138 }
 139
 140
 141 /* Look up the definition of the macro named NAME in scope at the source
 142    location given by BATON, which must be a pointer to a `struct
 143    macro_scope' structure.  */
 144 struct macro_definition *
 145 standard_macro_lookup (const char *name, void *baton)
 146 {
 147   struct macro_scope *ms = (struct macro_scope *) baton;
 148   struct macro_definition *result;
 149
 150   /* Give user-defined macros priority over all others.  */
 151   result = macro_lookup_definition (macro_main (macro_user_macros), -1, name);
 152   if (! result)
 153     result = macro_lookup_definition (ms->file, ms->line, name);
 154   return result;
 155 }
 156
 157 /* Provide a prototype to silence -Wmissing-prototypes.  */
 158 extern initialize_file_ftype _initialize_macroscope;
 159
 160 void
 161 _initialize_macroscope (void)
 162 {
 163   macro_user_macros = new_macro_table (0, 0);
 164   macro_set_main (macro_user_macros, "<user-defined>");
 165   macro_allow_redefinitions (macro_user_macros);
 166 }