Subversion Repositories openrisc_2011-10-31

/* Helper routines for C++ support in GDB.

   Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc.

   Contributed by David Carlton and by Kealia, 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 "cp-support.h"

#include "gdb_obstack.h"

#include "symtab.h"

#include "symfile.h"

#include "gdb_assert.h"

#include "block.h"

#include "objfiles.h"

#include "gdbtypes.h"

#include "dictionary.h"

#include "command.h"

#include "frame.h"

/* When set, the file that we're processing is known to have debugging

   info for C++ namespaces.  */

/* NOTE: carlton/2004-01-13: No currently released version of GCC (the

   latest of which is 3.3.x at the time of this writing) produces this

   debug info.  GCC 3.4 should, however.  */

unsigned char processing_has_namespace_info;

/* This contains our best guess as to the name of the current

   enclosing namespace(s)/class(es), if any.  For example, if we're

   within the method foo() in the following code:

    namespace N {

      class C {

        void foo () {

        }

      };

    }

   then processing_current_prefix should be set to "N::C".  If

   processing_has_namespace_info is false, then this variable might

   not be reliable.  */

const char *processing_current_prefix;

/* List of using directives that are active in the current file.  */

static struct using_direct *using_list;

static struct using_direct *cp_add_using (const char *name,

                                          unsigned int inner_len,

                                          unsigned int outer_len,

                                          struct using_direct *next);

static struct using_direct *cp_copy_usings (struct using_direct *using,

                                            struct obstack *obstack);

static struct symbol *lookup_namespace_scope (const char *name,

                                              const char *linkage_name,

                                              const struct block *block,

                                              const domain_enum domain,

                                              struct symtab **symtab,

                                              const char *scope,

                                              int scope_len);

static struct symbol *lookup_symbol_file (const char *name,

                                          const char *linkage_name,

                                          const struct block *block,

                                          const domain_enum domain,

                                          struct symtab **symtab,

                                          int anonymous_namespace);

static struct type *cp_lookup_transparent_type_loop (const char *name,

                                                     const char *scope,

                                                     int scope_len);

static void initialize_namespace_symtab (struct objfile *objfile);

static struct block *get_possible_namespace_block (struct objfile *objfile);

static void free_namespace_block (struct symtab *symtab);

static int check_possible_namespace_symbols_loop (const char *name,

                                                  int len,

                                                  struct objfile *objfile);

static int check_one_possible_namespace_symbol (const char *name,

                                                int len,

                                                struct objfile *objfile);

static

struct symbol *lookup_possible_namespace_symbol (const char *name,

                                                 struct symtab **symtab);

static void maintenance_cplus_namespace (char *args, int from_tty);

/* Set up support for dealing with C++ namespace info in the current

   symtab.  */

void cp_initialize_namespace ()

{

  processing_has_namespace_info = 0;

  using_list = NULL;

}

/* Add all the using directives we've gathered to the current symtab.

   STATIC_BLOCK should be the symtab's static block; OBSTACK is used

   for allocation.  */

void

cp_finalize_namespace (struct block *static_block,

                       struct obstack *obstack)

{

  if (using_list != NULL)

    {

      block_set_using (static_block,

                       cp_copy_usings (using_list, obstack),

                       obstack);

      using_list = NULL;

    }

}

/* Check to see if SYMBOL refers to an object contained within an

   anonymous namespace; if so, add an appropriate using directive.  */

/* Optimize away strlen ("(anonymous namespace)").  */

#define ANONYMOUS_NAMESPACE_LEN 21

void

cp_scan_for_anonymous_namespaces (const struct symbol *symbol)

{

  if (!processing_has_namespace_info

      && SYMBOL_CPLUS_DEMANGLED_NAME (symbol) != NULL)

    {

      const char *name = SYMBOL_CPLUS_DEMANGLED_NAME (symbol);

      unsigned int previous_component;

      unsigned int next_component;

      const char *len;

      /* Start with a quick-and-dirty check for mention of "(anonymous

         namespace)".  */

      if (!cp_is_anonymous (name))

        return;

      previous_component = 0;

      next_component = cp_find_first_component (name + previous_component);

      while (name[next_component] == ':')

        {

          if ((next_component - previous_component) == ANONYMOUS_NAMESPACE_LEN

              && strncmp (name + previous_component,

                          "(anonymous namespace)",

                          ANONYMOUS_NAMESPACE_LEN) == 0)

            {

              /* We've found a component of the name that's an

                 anonymous namespace.  So add symbols in it to the

                 namespace given by the previous component if there is

                 one, or to the global namespace if there isn't.  */

              cp_add_using_directive (name,

                                      previous_component == 0

                                      ? 0 : previous_component - 2,

                                      next_component);

            }

          /* The "+ 2" is for the "::".  */

          previous_component = next_component + 2;

          next_component = (previous_component

                            + cp_find_first_component (name

                                                       + previous_component));

        }

    }

}

/* Add a using directive to using_list.  NAME is the start of a string

   that should contain the namespaces we want to add as initial

   substrings, OUTER_LENGTH is the end of the outer namespace, and

   INNER_LENGTH is the end of the inner namespace.  If the using

   directive in question has already been added, don't add it

   twice.  */

void

cp_add_using_directive (const char *name, unsigned int outer_length,

                        unsigned int inner_length)

{

  struct using_direct *current;

  struct using_direct *new;

  /* Has it already been added?  */

  for (current = using_list; current != NULL; current = current->next)

    {

      if ((strncmp (current->inner, name, inner_length) == 0)

          && (strlen (current->inner) == inner_length)

          && (strlen (current->outer) == outer_length))

        return;

    }

  using_list = cp_add_using (name, inner_length, outer_length,

                             using_list);

}

/* Record the namespace that the function defined by SYMBOL was

   defined in, if necessary.  BLOCK is the associated block; use

   OBSTACK for allocation.  */

void

cp_set_block_scope (const struct symbol *symbol,

                    struct block *block,

                    struct obstack *obstack)

{

  /* Make sure that the name was originally mangled: if not, there

     certainly isn't any namespace information to worry about!  */

  if (SYMBOL_CPLUS_DEMANGLED_NAME (symbol) != NULL)

    {

      if (processing_has_namespace_info)

        {

          block_set_scope

            (block, obsavestring (processing_current_prefix,

                                  strlen (processing_current_prefix),

                                  obstack),

             obstack);

        }

      else

        {

          /* Try to figure out the appropriate namespace from the

             demangled name.  */

          /* FIXME: carlton/2003-04-15: If the function in question is

             a method of a class, the name will actually include the

             name of the class as well.  This should be harmless, but

             is a little unfortunate.  */

          const char *name = SYMBOL_CPLUS_DEMANGLED_NAME (symbol);

          unsigned int prefix_len = cp_entire_prefix_len (name);

          block_set_scope (block,

                           obsavestring (name, prefix_len, obstack),

                           obstack);

        }

    }

}

/* Test whether or not NAMESPACE looks like it mentions an anonymous

   namespace; return nonzero if so.  */

int

cp_is_anonymous (const char *namespace)

{

  return (strstr (namespace, "(anonymous namespace)")

          != NULL);

}

/* Create a new struct using direct whose inner namespace is the

   initial substring of NAME of leng INNER_LEN and whose outer

   namespace is the initial substring of NAME of length OUTER_LENGTH.

   Set its next member in the linked list to NEXT; allocate all memory

   using xmalloc.  It copies the strings, so NAME can be a temporary

   string.  */

static struct using_direct *

cp_add_using (const char *name,

              unsigned int inner_len,

              unsigned int outer_len,

              struct using_direct *next)

{

  struct using_direct *retval;

  gdb_assert (outer_len < inner_len);

  retval = xmalloc (sizeof (struct using_direct));

  retval->inner = savestring (name, inner_len);

  retval->outer = savestring (name, outer_len);

  retval->next = next;

  return retval;

}

/* Make a copy of the using directives in the list pointed to by

   USING, using OBSTACK to allocate memory.  Free all memory pointed

   to by USING via xfree.  */

static struct using_direct *

cp_copy_usings (struct using_direct *using,

                struct obstack *obstack)

{

  if (using == NULL)

    {

      return NULL;

    }

  else

    {

      struct using_direct *retval

        = obstack_alloc (obstack, sizeof (struct using_direct));

      retval->inner = obsavestring (using->inner, strlen (using->inner),

                                    obstack);

      retval->outer = obsavestring (using->outer, strlen (using->outer),

                                    obstack);

      retval->next = cp_copy_usings (using->next, obstack);

      xfree (using->inner);

      xfree (using->outer);

      xfree (using);

      return retval;

    }

}

/* The C++-specific version of name lookup for static and global

   names.  This makes sure that names get looked for in all namespaces

   that are in scope.  NAME is the natural name of the symbol that

   we're looking for, LINKAGE_NAME (which is optional) is its linkage

   name, BLOCK is the block that we're searching within, DOMAIN says

   what kind of symbols we're looking for, and if SYMTAB is non-NULL,

   we should store the symtab where we found the symbol in it.  */

struct symbol *

cp_lookup_symbol_nonlocal (const char *name,

                           const char *linkage_name,

                           const struct block *block,

                           const domain_enum domain,

                           struct symtab **symtab)

{

  return lookup_namespace_scope (name, linkage_name, block, domain,

                                 symtab, block_scope (block), 0);

}

/* Lookup NAME at namespace scope (or, in C terms, in static and

   global variables).  SCOPE is the namespace that the current

   function is defined within; only consider namespaces whose length

   is at least SCOPE_LEN.  Other arguments are as in

   cp_lookup_symbol_nonlocal.

   For example, if we're within a function A::B::f and looking for a

   symbol x, this will get called with NAME = "x", SCOPE = "A::B", and

   SCOPE_LEN = 0.  It then calls itself with NAME and SCOPE the same,

   but with SCOPE_LEN = 1.  And then it calls itself with NAME and

   SCOPE the same, but with SCOPE_LEN = 4.  This third call looks for

   "A::B::x"; if it doesn't find it, then the second call looks for

   "A::x", and if that call fails, then the first call looks for

   "x".  */

static struct symbol *

lookup_namespace_scope (const char *name,

                        const char *linkage_name,

                        const struct block *block,

                        const domain_enum domain,

                        struct symtab **symtab,

                        const char *scope,

                        int scope_len)

{

  char *namespace;

  if (scope[scope_len] != '\0')

    {

      /* Recursively search for names in child namespaces first.  */

      struct symbol *sym;

      int new_scope_len = scope_len;

      /* If the current scope is followed by "::", skip past that.  */

      if (new_scope_len != 0)

        {

          gdb_assert (scope[new_scope_len] == ':');

          new_scope_len += 2;

        }

      new_scope_len += cp_find_first_component (scope + new_scope_len);

      sym = lookup_namespace_scope (name, linkage_name, block,

                                    domain, symtab,

                                    scope, new_scope_len);

      if (sym != NULL)

        return sym;

    }

  /* Okay, we didn't find a match in our children, so look for the

     name in the current namespace.  */

  namespace = alloca (scope_len + 1);

  strncpy (namespace, scope, scope_len);

  namespace[scope_len] = '\0';

  return cp_lookup_symbol_namespace (namespace, name, linkage_name,

                                     block, domain, symtab);

}

/* Look up NAME in the C++ namespace NAMESPACE, applying the using

   directives that are active in BLOCK.  Other arguments are as in

   cp_lookup_symbol_nonlocal.  */

struct symbol *

cp_lookup_symbol_namespace (const char *namespace,

                            const char *name,

                            const char *linkage_name,

                            const struct block *block,

                            const domain_enum domain,

                            struct symtab **symtab)

{

  const struct using_direct *current;

  struct symbol *sym;

  /* First, go through the using directives.  If any of them add new

     names to the namespace we're searching in, see if we can find a

     match by applying them.  */

  for (current = block_using (block);

       current != NULL;

       current = current->next)

    {

      if (strcmp (namespace, current->outer) == 0)

        {

          sym = cp_lookup_symbol_namespace (current->inner,

                                            name,

                                            linkage_name,

                                            block,

                                            domain,

                                            symtab);

          if (sym != NULL)

            return sym;

        }

    }

  /* We didn't find anything by applying any of the using directives

     that are still applicable; so let's see if we've got a match

     using the current namespace.  */

  if (namespace[0] == '\0')

    {

      return lookup_symbol_file (name, linkage_name, block,

                                 domain, symtab, 0);

    }

  else

    {

      char *concatenated_name

        = alloca (strlen (namespace) + 2 + strlen (name) + 1);

      strcpy (concatenated_name, namespace);

      strcat (concatenated_name, "::");

      strcat (concatenated_name, name);

      sym = lookup_symbol_file (concatenated_name, linkage_name,

                                block, domain, symtab,

                                cp_is_anonymous (namespace));

      return sym;

    }

}

/* Look up NAME in BLOCK's static block and in global blocks.  If

   ANONYMOUS_NAMESPACE is nonzero, the symbol in question is located

   within an anonymous namespace.  Other arguments are as in

   cp_lookup_symbol_nonlocal.  */

static struct symbol *

lookup_symbol_file (const char *name,

                    const char *linkage_name,

                    const struct block *block,

                    const domain_enum domain,

                    struct symtab **symtab,

                    int anonymous_namespace)

{

  struct symbol *sym = NULL;

  sym = lookup_symbol_static (name, linkage_name, block, domain, symtab);

  if (sym != NULL)

    return sym;

  if (anonymous_namespace)

    {

      /* Symbols defined in anonymous namespaces have external linkage

         but should be treated as local to a single file nonetheless.

         So we only search the current file's global block.  */

      const struct block *global_block = block_global_block (block);

      if (global_block != NULL)

        sym = lookup_symbol_aux_block (name, linkage_name, global_block,

                                       domain, symtab);

    }

  else

    {

      sym = lookup_symbol_global (name, linkage_name, block, domain, symtab);

    }

  if (sym != NULL)

    return sym;

  /* Now call "lookup_possible_namespace_symbol".  Symbols in here

     claim to be associated to namespaces, but this claim might be

     incorrect: the names in question might actually correspond to

     classes instead of namespaces.  But if they correspond to

     classes, then we should have found a match for them above.  So if

     we find them now, they should be genuine.  */

  /* FIXME: carlton/2003-06-12: This is a hack and should eventually

     be deleted: see comments below.  */

  if (domain == VAR_DOMAIN)

    {

      sym = lookup_possible_namespace_symbol (name, symtab);

      if (sym != NULL)

        return sym;

    }

  return NULL;

}

/* Look up a type named NESTED_NAME that is nested inside the C++

   class or namespace given by PARENT_TYPE, from within the context

   given by BLOCK.  Return NULL if there is no such nested type.  */

struct type *

cp_lookup_nested_type (struct type *parent_type,

                       const char *nested_name,

                       const struct block *block)

{

  switch (TYPE_CODE (parent_type))

    {

    case TYPE_CODE_STRUCT:

    case TYPE_CODE_NAMESPACE:

      {

        /* NOTE: carlton/2003-11-10: We don't treat C++ class members

           of classes like, say, data or function members.  Instead,

           they're just represented by symbols whose names are

           qualified by the name of the surrounding class.  This is

           just like members of namespaces; in particular,

           lookup_symbol_namespace works when looking them up.  */

        const char *parent_name = TYPE_TAG_NAME (parent_type);

        struct symbol *sym = cp_lookup_symbol_namespace (parent_name,

                                                         nested_name,

                                                         NULL,

                                                         block,

                                                         VAR_DOMAIN,

                                                         NULL);

        if (sym == NULL || SYMBOL_CLASS (sym) != LOC_TYPEDEF)

          return NULL;

        else

          return SYMBOL_TYPE (sym);

      }

    default:

      internal_error (__FILE__, __LINE__,

                      _("cp_lookup_nested_type called on a non-aggregate type."));

    }

}

/* The C++-version of lookup_transparent_type.  */

/* FIXME: carlton/2004-01-16: The problem that this is trying to

   address is that, unfortunately, sometimes NAME is wrong: it may not

   include the name of namespaces enclosing the type in question.

   lookup_transparent_type gets called when the the type in question

   is a declaration, and we're trying to find its definition; but, for

   declarations, our type name deduction mechanism doesn't work.

   There's nothing we can do to fix this in general, I think, in the

   absence of debug information about namespaces (I've filed PR

   gdb/1511 about this); until such debug information becomes more

   prevalent, one heuristic which sometimes looks is to search for the

   definition in namespaces containing the current namespace.

   We should delete this functions once the appropriate debug

   information becomes more widespread.  (GCC 3.4 will be the first

   released version of GCC with such information.)  */

struct type *

cp_lookup_transparent_type (const char *name)

{

  /* First, try the honest way of looking up the definition.  */

  struct type *t = basic_lookup_transparent_type (name);

  const char *scope;

  if (t != NULL)

    return t;

  /* If that doesn't work and we're within a namespace, look there

     instead.  */

  scope = block_scope (get_selected_block (0));

  if (scope[0] == '\0')

    return NULL;

  return cp_lookup_transparent_type_loop (name, scope, 0);

}

/* Lookup the the type definition associated to NAME in

   namespaces/classes containing SCOPE whose name is strictly longer

   than LENGTH.  LENGTH must be the index of the start of a

   component of SCOPE.  */

static struct type *

cp_lookup_transparent_type_loop (const char *name, const char *scope,

                                 int length)

{

  int scope_length = length + cp_find_first_component (scope + length);

  char *full_name;

  /* If the current scope is followed by "::", look in the next

     component.  */

  if (scope[scope_length] == ':')

    {

      struct type *retval

        = cp_lookup_transparent_type_loop (name, scope, scope_length + 2);

      if (retval != NULL)

        return retval;

    }

  full_name = alloca (scope_length + 2 + strlen (name) + 1);

  strncpy (full_name, scope, scope_length);

  strncpy (full_name + scope_length, "::", 2);

  strcpy (full_name + scope_length + 2, name);

  return basic_lookup_transparent_type (full_name);

}

/* Now come functions for dealing with symbols associated to

   namespaces.  (They're used to store the namespaces themselves, not

   objects that live in the namespaces.)  These symbols come in two

   varieties: if we run into a DW_TAG_namespace DIE, then we know that

   we have a namespace, so dwarf2read.c creates a symbol for it just

   like normal.  But, unfortunately, versions of GCC through at least

   3.3 don't generate those DIE's.  Our solution is to try to guess

   their existence by looking at demangled names.  This might cause us

   to misidentify classes as namespaces, however.  So we put those

   symbols in a special block (one per objfile), and we only search

   that block as a last resort.  */

/* FIXME: carlton/2003-06-12: Once versions of GCC that generate

   DW_TAG_namespace have been out for a year or two, we should get rid

   of all of this "possible namespace" nonsense.  */

/* Allocate everything necessary for the possible namespace block

   associated to OBJFILE.  */

static void

initialize_namespace_symtab (struct objfile *objfile)

{

  struct symtab *namespace_symtab;

  struct blockvector *bv;

  struct block *bl;

  namespace_symtab = allocate_symtab ("<<C++-namespaces>>", objfile);

  namespace_symtab->language = language_cplus;

  namespace_symtab->free_code = free_nothing;

  namespace_symtab->dirname = NULL;

  bv = obstack_alloc (&objfile->objfile_obstack,

                      sizeof (struct blockvector)

                      + FIRST_LOCAL_BLOCK * sizeof (struct block *));

  BLOCKVECTOR_NBLOCKS (bv) = FIRST_LOCAL_BLOCK + 1;

  BLOCKVECTOR (namespace_symtab) = bv;

  /* Allocate empty GLOBAL_BLOCK and STATIC_BLOCK. */

  bl = allocate_block (&objfile->objfile_obstack);

  BLOCK_DICT (bl) = dict_create_linear (&objfile->objfile_obstack,

                                        NULL);

  BLOCKVECTOR_BLOCK (bv, GLOBAL_BLOCK) = bl;

  bl = allocate_block (&objfile->objfile_obstack);

  BLOCK_DICT (bl) = dict_create_linear (&objfile->objfile_obstack,

                                        NULL);

  BLOCKVECTOR_BLOCK (bv, STATIC_BLOCK) = bl;

  /* Allocate the possible namespace block; we put it where the first

     local block will live, though I don't think there's any need to

     pretend that it's actually a local block (e.g. by setting

     BLOCK_SUPERBLOCK appropriately).  We don't use the global or

     static block because we don't want it searched during the normal

     search of all global/static blocks in lookup_symbol: we only want

     it used as a last resort.  */

  /* NOTE: carlton/2003-09-11: I considered not associating the fake

     symbols to a block/symtab at all.  But that would cause problems

     with lookup_symbol's SYMTAB argument and with block_found, so

     having a symtab/block for this purpose seems like the best

     solution for now.  */

  bl = allocate_block (&objfile->objfile_obstack);

  BLOCK_DICT (bl) = dict_create_hashed_expandable ();

  BLOCKVECTOR_BLOCK (bv, FIRST_LOCAL_BLOCK) = bl;

  namespace_symtab->free_func = free_namespace_block;

  objfile->cp_namespace_symtab = namespace_symtab;

}

/* Locate the possible namespace block associated to OBJFILE,

   allocating it if necessary.  */

static struct block *

get_possible_namespace_block (struct objfile *objfile)

{

  if (objfile->cp_namespace_symtab == NULL)

    initialize_namespace_symtab (objfile);

  return BLOCKVECTOR_BLOCK (BLOCKVECTOR (objfile->cp_namespace_symtab),

                            FIRST_LOCAL_BLOCK);

}

/* Free the dictionary associated to the possible namespace block.  */

static void

free_namespace_block (struct symtab *symtab)

{

  struct block *possible_namespace_block;

  possible_namespace_block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab),

                                                FIRST_LOCAL_BLOCK);

  gdb_assert (possible_namespace_block != NULL);

  dict_free (BLOCK_DICT (possible_namespace_block));

}

/* Ensure that there are symbols in the possible namespace block

   associated to OBJFILE for all initial substrings of NAME that look

   like namespaces or classes.  NAME should end in a member variable:

   it shouldn't consist solely of namespaces.  */

void

cp_check_possible_namespace_symbols (const char *name, struct objfile *objfile)

{

  check_possible_namespace_symbols_loop (name,