binutils-gdb/gdb/target-descriptions.c

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/* Target description support for GDB.
Copyright (C) 2006
Free Software Foundation, Inc.
Contributed by CodeSourcery.
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 2 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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include "defs.h"
#include "arch-utils.h"
#include "target.h"
#include "target-descriptions.h"
#include "gdb_assert.h"
/* Types. */
struct target_desc
{
};
/* Global state. These variables are associated with the current
target; if GDB adds support for multiple simultaneous targets, then
these variables should become target-specific data. */
/* A flag indicating that a description has already been fetched from
the current target, so it should not be queried again. */
static int target_desc_fetched;
/* The description fetched from the current target, or NULL if the
current target did not supply any description. Only valid when
target_desc_fetched is set. Only the description initialization
code should access this; normally, the description should be
accessed through the gdbarch object. */
static const struct target_desc *current_target_desc;
/* Fetch the current target's description, and switch the current
architecture to one which incorporates that description. */
void
target_find_description (void)
{
/* If we've already fetched a description from the target, don't do
it again. This allows a target to fetch the description early,
during its to_open or to_create_inferior, if it needs extra
information about the target to initialize. */
if (target_desc_fetched)
return;
/* The current architecture should not have any target description
specified. It should have been cleared, e.g. when we
disconnected from the previous target. */
gdb_assert (gdbarch_target_desc (current_gdbarch) == NULL);
current_target_desc = target_read_description (&current_target);
/* If a non-NULL description was returned, then update the current
architecture. */
if (current_target_desc)
{
struct gdbarch_info info;
gdbarch_info_init (&info);
info.target_desc = current_target_desc;
if (!gdbarch_update_p (info))
warning (_("Could not use target-supplied description"));
}
/* Now that we know this description is usable, record that we
fetched it. */
target_desc_fetched = 1;
}
/* Discard any description fetched from the current target, and switch
the current architecture to one with no target description. */
void
target_clear_description (void)
{
struct gdbarch_info info;
if (!target_desc_fetched)
return;
target_desc_fetched = 0;
current_target_desc = NULL;
gdbarch_info_init (&info);
if (!gdbarch_update_p (info))
internal_error (__FILE__, __LINE__,
_("Could not remove target-supplied description"));
}
/* Return the global current target description. This should only be
used by gdbarch initialization code; most access should be through
an existing gdbarch. */
const struct target_desc *
target_current_description (void)
{
if (target_desc_fetched)
return current_target_desc;
return NULL;
}
/* Methods for constructing a target description. */
struct target_desc *
allocate_target_description (void)
{
return XZALLOC (struct target_desc);
}