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/* Functions for deciding which macros are currently in scope.

   Copyright (C) 2002, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

   Contributed by Red Hat, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "macroscope.h"

#include "symtab.h"

#include "source.h"

#include "target.h"

#include "frame.h"

#include "inferior.h"

#include "complaints.h"

/* A table of user-defined macros.  Unlike the macro tables used for

   symtabs, this one uses xmalloc for all its allocation, not an

   obstack, and it doesn't bcache anything; it just xmallocs things.  So

   it's perfectly possible to remove things from this, or redefine

   things.  */

struct macro_table *macro_user_macros;

struct macro_scope *

sal_macro_scope (struct symtab_and_line sal)

{

  struct macro_source_file *main_file, *inclusion;

  struct macro_scope *ms;

  if (! sal.symtab

      || ! sal.symtab->macro_table)

    return 0;

  ms = (struct macro_scope *) xmalloc (sizeof (*ms));

  main_file = macro_main (sal.symtab->macro_table);

  inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);

  if (inclusion)

    {

      ms->file = inclusion;

      ms->line = sal.line;

    }

  else

    {

      /* There are, unfortunately, cases where a compilation unit can

         have a symtab for a source file that doesn't appear in the

         macro table.  For example, at the moment, Dwarf doesn't have

         any way in the .debug_macinfo section to describe the effect

         of #line directives, so if you debug a YACC parser you'll get

         a macro table which only mentions the .c files generated by

         YACC, but symtabs that mention the .y files consumed by YACC.

         In the long run, we should extend the Dwarf macro info

         representation to handle #line directives, and get GCC to

         emit it.

         For the time being, though, we'll just treat these as

         occurring at the end of the main source file.  */

      ms->file = main_file;

      ms->line = -1;

      complaint (&symfile_complaints,

                 _("symtab found for `%s', but that file\n"

                 "is not covered in the compilation unit's macro information"),

                 sal.symtab->filename);

    }

  return ms;

}

struct macro_scope *

user_macro_scope (void)

{

  struct macro_scope *ms;

  ms = XNEW (struct macro_scope);

  ms->file = macro_main (macro_user_macros);

  ms->line = -1;

  return ms;

}

struct macro_scope *

default_macro_scope (void)

{

  struct symtab_and_line sal;

  struct macro_scope *ms;

  struct frame_info *frame;

  /* If there's a selected frame, use its PC.  */

  frame = deprecated_safe_get_selected_frame ();

  if (frame)

    sal = find_pc_line (get_frame_pc (frame), 0);

  /* Fall back to the current listing position.  */

  else

    {

      /* Don't call select_source_symtab here.  That can raise an

         error if symbols aren't loaded, but GDB calls the expression

         evaluator in all sorts of contexts.

         For example, commands like `set width' call the expression

         evaluator to evaluate their numeric arguments.  If the

         current language is C, then that may call this function to

         choose a scope for macro expansion.  If you don't have any

         symbol files loaded, then get_current_or_default would raise an

         error.  But `set width' shouldn't raise an error just because

         it can't decide which scope to macro-expand its argument in.  */

      struct symtab_and_line cursal =

                        get_current_source_symtab_and_line ();

      sal.symtab = cursal.symtab;

      sal.line = cursal.line;

    }

  ms = sal_macro_scope (sal);

  if (! ms)

    ms = user_macro_scope ();

  return ms;

}

/* Look up the definition of the macro named NAME in scope at the source

   location given by BATON, which must be a pointer to a `struct

   macro_scope' structure.  */

struct macro_definition *

standard_macro_lookup (const char *name, void *baton)

{

  struct macro_scope *ms = (struct macro_scope *) baton;

  struct macro_definition *result;

  /* Give user-defined macros priority over all others.  */

  result = macro_lookup_definition (macro_main (macro_user_macros), -1, name);

  if (! result)

    result = macro_lookup_definition (ms->file, ms->line, name);

  return result;

}

/* Provide a prototype to silence -Wmissing-prototypes.  */

extern initialize_file_ftype _initialize_macroscope;

void

_initialize_macroscope (void)

{

  macro_user_macros = new_macro_table (0, 0);

  macro_set_main (macro_user_macros, "<user-defined>");

  macro_allow_redefinitions (macro_user_macros);

}