gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002, 2007, 2008, 2009 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 /* A table of user-defined macros.  Unlike the macro tables used for
  31    symtabs, this one uses xmalloc for all its allocation, not an
  32    obstack, and it doesn't bcache anything; it just xmallocs things.  So
  33    it's perfectly possible to remove things from this, or redefine
  34    things.  */
  35 struct macro_table *macro_user_macros;
  36
  37
  38 struct macro_scope *
  39 sal_macro_scope (struct symtab_and_line sal)
  40 {
  41   struct macro_source_file *main_file, *inclusion;
  42   struct macro_scope *ms;
  43
  44   if (! sal.symtab
  45       || ! sal.symtab->macro_table)
  46     return 0;
  47
  48   ms = (struct macro_scope *) xmalloc (sizeof (*ms));
  49
  50   main_file = macro_main (sal.symtab->macro_table);
  51   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
  52
  53   if (inclusion)
  54     {
  55       ms->file = inclusion;
  56       ms->line = sal.line;
  57     }
  58   else
  59     {
  60       /* There are, unfortunately, cases where a compilation unit can
  61          have a symtab for a source file that doesn't appear in the
  62          macro table.  For example, at the moment, Dwarf doesn't have
  63          any way in the .debug_macinfo section to describe the effect
  64          of #line directives, so if you debug a YACC parser you'll get
  65          a macro table which only mentions the .c files generated by
  66          YACC, but symtabs that mention the .y files consumed by YACC.
  67
  68          In the long run, we should extend the Dwarf macro info
  69          representation to handle #line directives, and get GCC to
  70          emit it.
  71
  72          For the time being, though, we'll just treat these as
  73          occurring at the end of the main source file.  */
  74       ms->file = main_file;
  75       ms->line = -1;
  76
  77       complaint (&symfile_complaints,
  78                  _("symtab found for `%s', but that file\n"
  79                  "is not covered in the compilation unit's macro information"),
  80                  sal.symtab->filename);
  81     }
  82
  83   return ms;
  84 }
  85
  86
  87 struct macro_scope *
  88 user_macro_scope (void)
  89 {
  90   struct macro_scope *ms;
  91   ms = XNEW (struct macro_scope);
  92   ms->file = macro_main (macro_user_macros);
  93   ms->line = -1;
  94   return ms;
  95 }
  96
  97 struct macro_scope *
  98 default_macro_scope (void)
  99 {
 100   struct symtab_and_line sal;
 101   struct macro_scope *ms;
 102   struct frame_info *frame;
 103
 104   /* If there's a selected frame, use its PC.  */
 105   frame = deprecated_safe_get_selected_frame ();
 106   if (frame)
 107     sal = find_pc_line (get_frame_pc (frame), 0);
 108
 109   /* Fall back to the current listing position.  */
 110   else
 111     {
 112       /* Don't call select_source_symtab here.  That can raise an
 113          error if symbols aren't loaded, but GDB calls the expression
 114          evaluator in all sorts of contexts.
 115
 116          For example, commands like `set width' call the expression
 117          evaluator to evaluate their numeric arguments.  If the
 118          current language is C, then that may call this function to
 119          choose a scope for macro expansion.  If you don't have any
 120          symbol files loaded, then get_current_or_default would raise an
 121          error.  But `set width' shouldn't raise an error just because
 122          it can't decide which scope to macro-expand its argument in.  */
 123       struct symtab_and_line cursal =
 124                         get_current_source_symtab_and_line ();
 125
 126       sal.symtab = cursal.symtab;
 127       sal.line = cursal.line;
 128     }
 129
 130   ms = sal_macro_scope (sal);
 131   if (! ms)
 132     ms = user_macro_scope ();
 133
 134   return ms;
 135 }
 136
 137
 138 /* Look up the definition of the macro named NAME in scope at the source
 139    location given by BATON, which must be a pointer to a `struct
 140    macro_scope' structure.  */
 141 struct macro_definition *
 142 standard_macro_lookup (const char *name, void *baton)
 143 {
 144   struct macro_scope *ms = (struct macro_scope *) baton;
 145   struct macro_definition *result;
 146
 147   /* Give user-defined macros priority over all others.  */
 148   result = macro_lookup_definition (macro_main (macro_user_macros), -1, name);
 149   if (! result)
 150     result = macro_lookup_definition (ms->file, ms->line, name);
 151   return result;
 152 }
 153
 154 /* Provide a prototype to silence -Wmissing-prototypes.  */
 155 extern initialize_file_ftype _initialize_macroscope;
 156
 157 void
 158 _initialize_macroscope (void)
 159 {
 160   macro_user_macros = new_macro_table (0, 0);
 161   macro_set_main (macro_user_macros, "<user-defined>");
 162   macro_allow_redefinitions (macro_user_macros);
 163 }