/* Definitions for frame unwinder, for GDB, the GNU debugger.
- Copyright 2003 Free Software Foundation, Inc.
+ Copyright (C) 2003-2020 Free Software Foundation, 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 2 of the License, or
+ 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,
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., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "frame.h"
#include "frame-unwind.h"
-#include "gdb_assert.h"
#include "dummy-frame.h"
+#include "inline-frame.h"
+#include "value.h"
+#include "regcache.h"
+#include "gdb_obstack.h"
+#include "target.h"
+#include "gdbarch.h"
+#include "dwarf2/frame-tailcall.h"
static struct gdbarch_data *frame_unwind_data;
+struct frame_unwind_table_entry
+{
+ const struct frame_unwind *unwinder;
+ struct frame_unwind_table_entry *next;
+};
+
struct frame_unwind_table
{
- frame_unwind_sniffer_ftype **sniffer;
- int nr;
+ struct frame_unwind_table_entry *list;
+ /* The head of the OSABI part of the search list. */
+ struct frame_unwind_table_entry **osabi_head;
};
-/* Append a predicate to the end of the table. */
-static void
-append_predicate (struct frame_unwind_table *table,
- frame_unwind_sniffer_ftype *sniffer)
+/* A helper function to add an unwinder to a list. LINK says where to
+ install the new unwinder. The new link is returned. */
+
+static struct frame_unwind_table_entry **
+add_unwinder (struct obstack *obstack, const struct frame_unwind *unwinder,
+ struct frame_unwind_table_entry **link)
{
- table->sniffer = xrealloc (table->sniffer, ((table->nr + 1)
- * sizeof (frame_unwind_sniffer_ftype *)));
- table->sniffer[table->nr] = sniffer;
- table->nr++;
+ *link = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
+ (*link)->unwinder = unwinder;
+ return &(*link)->next;
}
static void *
-frame_unwind_init (struct gdbarch *gdbarch)
+frame_unwind_init (struct obstack *obstack)
{
- struct frame_unwind_table *table = XCALLOC (1, struct frame_unwind_table);
- append_predicate (table, dummy_frame_sniffer);
+ struct frame_unwind_table *table
+ = OBSTACK_ZALLOC (obstack, struct frame_unwind_table);
+
+ /* Start the table out with a few default sniffers. OSABI code
+ can't override this. */
+ struct frame_unwind_table_entry **link = &table->list;
+
+ link = add_unwinder (obstack, &dummy_frame_unwind, link);
+ /* The DWARF tailcall sniffer must come before the inline sniffer.
+ Otherwise, we can end up in a situation where a DWARF frame finds
+ tailcall information, but then the inline sniffer claims a frame
+ before the tailcall sniffer, resulting in confusion. This is
+ safe to do always because the tailcall sniffer can only ever be
+ activated if the newer frame was created using the DWARF
+ unwinder, and it also found tailcall information. */
+ link = add_unwinder (obstack, &dwarf2_tailcall_frame_unwind, link);
+ link = add_unwinder (obstack, &inline_frame_unwind, link);
+
+ /* The insertion point for OSABI sniffers. */
+ table->osabi_head = link;
return table;
}
void
-frame_unwind_append_sniffer (struct gdbarch *gdbarch,
- frame_unwind_sniffer_ftype *sniffer)
+frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
+ const struct frame_unwind *unwinder)
+{
+ struct frame_unwind_table *table
+ = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
+ struct frame_unwind_table_entry *entry;
+
+ /* Insert the new entry at the start of the list. */
+ entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
+ entry->unwinder = unwinder;
+ entry->next = (*table->osabi_head);
+ (*table->osabi_head) = entry;
+}
+
+void
+frame_unwind_append_unwinder (struct gdbarch *gdbarch,
+ const struct frame_unwind *unwinder)
+{
+ struct frame_unwind_table *table
+ = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
+ struct frame_unwind_table_entry **ip;
+
+ /* Find the end of the list and insert the new entry there. */
+ for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next);
+ (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
+ (*ip)->unwinder = unwinder;
+}
+
+/* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for
+ THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME
+ unchanged and returns 0. */
+
+static int
+frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
+ const struct frame_unwind *unwinder)
{
- struct frame_unwind_table *table =
- gdbarch_data (gdbarch, frame_unwind_data);
- if (table == NULL)
+ int res = 0;
+
+ frame_prepare_for_sniffer (this_frame, unwinder);
+
+ try
{
- /* ULGH, called during architecture initialization. Patch
- things up. */
- table = frame_unwind_init (gdbarch);
- deprecated_set_gdbarch_data (gdbarch, frame_unwind_data, table);
+ res = unwinder->sniffer (unwinder, this_frame, this_cache);
}
- append_predicate (table, sniffer);
-}
-
-const struct frame_unwind *
-frame_unwind_find_by_frame (struct frame_info *next_frame)
-{
- int i;
- struct gdbarch *gdbarch = get_frame_arch (next_frame);
- struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
- if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES && legacy_frame_p (gdbarch))
- /* Seriously old code. Don't even try to use this new mechanism.
- (Note: The variable USE_GENERIC_DUMMY_FRAMES is deprecated, not
- the dummy frame mechanism. All architectures should be using
- generic dummy frames). */
- return legacy_saved_regs_unwind;
- for (i = 0; i < table->nr; i++)
+ catch (const gdb_exception &ex)
{
- const struct frame_unwind *desc;
- desc = table->sniffer[i] (next_frame);
- if (desc != NULL)
- return desc;
+ /* Catch all exceptions, caused by either interrupt or error.
+ Reset *THIS_CACHE. */
+ *this_cache = NULL;
+ frame_cleanup_after_sniffer (this_frame);
+
+ if (ex.error == NOT_AVAILABLE_ERROR)
+ {
+ /* This usually means that not even the PC is available,
+ thus most unwinders aren't able to determine if they're
+ the best fit. Keep trying. Fallback prologue unwinders
+ should always accept the frame. */
+ return 0;
+ }
+ throw;
}
- return legacy_saved_regs_unwind;
+
+ if (res)
+ return 1;
+ else
+ {
+ /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
+ so. */
+ frame_cleanup_after_sniffer (this_frame);
+ return 0;
+ }
+ gdb_assert_not_reached ("frame_unwind_try_unwinder");
}
-extern initialize_file_ftype _initialize_frame_unwind; /* -Wmissing-prototypes */
+/* Iterate through sniffers for THIS_FRAME frame until one returns with an
+ unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
+ by this function. Possibly initialize THIS_CACHE. */
+
+void
+frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache)
+{
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ struct frame_unwind_table *table
+ = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
+ struct frame_unwind_table_entry *entry;
+ const struct frame_unwind *unwinder_from_target;
+
+ unwinder_from_target = target_get_unwinder ();
+ if (unwinder_from_target != NULL
+ && frame_unwind_try_unwinder (this_frame, this_cache,
+ unwinder_from_target))
+ return;
+
+ unwinder_from_target = target_get_tailcall_unwinder ();
+ if (unwinder_from_target != NULL
+ && frame_unwind_try_unwinder (this_frame, this_cache,
+ unwinder_from_target))
+ return;
+
+ for (entry = table->list; entry != NULL; entry = entry->next)
+ if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder))
+ return;
+
+ internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed"));
+}
+
+/* A default frame sniffer which always accepts the frame. Used by
+ fallback prologue unwinders. */
+
+int
+default_frame_sniffer (const struct frame_unwind *self,
+ struct frame_info *this_frame,
+ void **this_prologue_cache)
+{
+ return 1;
+}
+
+/* The default frame unwinder stop_reason callback. */
+
+enum unwind_stop_reason
+default_frame_unwind_stop_reason (struct frame_info *this_frame,
+ void **this_cache)
+{
+ struct frame_id this_id = get_frame_id (this_frame);
+
+ if (frame_id_eq (this_id, outer_frame_id))
+ return UNWIND_OUTERMOST;
+ else
+ return UNWIND_NO_REASON;
+}
+
+/* See frame-unwind.h. */
+
+CORE_ADDR
+default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+ int pc_regnum = gdbarch_pc_regnum (gdbarch);
+ CORE_ADDR pc = frame_unwind_register_unsigned (next_frame, pc_regnum);
+ pc = gdbarch_addr_bits_remove (gdbarch, pc);
+ return pc;
+}
+
+/* See frame-unwind.h. */
+
+CORE_ADDR
+default_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+ int sp_regnum = gdbarch_sp_regnum (gdbarch);
+ return frame_unwind_register_unsigned (next_frame, sp_regnum);
+}
+
+/* Helper functions for value-based register unwinding. These return
+ a (possibly lazy) value of the appropriate type. */
+
+/* Return a value which indicates that FRAME did not save REGNUM. */
+
+struct value *
+frame_unwind_got_optimized (struct frame_info *frame, int regnum)
+{
+ struct gdbarch *gdbarch = frame_unwind_arch (frame);
+ struct type *type = register_type (gdbarch, regnum);
+ struct value *val;
+
+ /* Return an lval_register value, so that we print it as
+ "<not saved>". */
+ val = allocate_value_lazy (type);
+ set_value_lazy (val, 0);
+ mark_value_bytes_optimized_out (val, 0, TYPE_LENGTH (type));
+ VALUE_LVAL (val) = lval_register;
+ VALUE_REGNUM (val) = regnum;
+ VALUE_NEXT_FRAME_ID (val)
+ = get_frame_id (get_next_frame_sentinel_okay (frame));
+ return val;
+}
+
+/* Return a value which indicates that FRAME copied REGNUM into
+ register NEW_REGNUM. */
+
+struct value *
+frame_unwind_got_register (struct frame_info *frame,
+ int regnum, int new_regnum)
+{
+ return value_of_register_lazy (frame, new_regnum);
+}
+
+/* Return a value which indicates that FRAME saved REGNUM in memory at
+ ADDR. */
+
+struct value *
+frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr)
+{
+ struct gdbarch *gdbarch = frame_unwind_arch (frame);
+ struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr);
+
+ set_value_stack (v, 1);
+ return v;
+}
+
+/* Return a value which indicates that FRAME's saved version of
+ REGNUM has a known constant (computed) value of VAL. */
+
+struct value *
+frame_unwind_got_constant (struct frame_info *frame, int regnum,
+ ULONGEST val)
+{
+ struct gdbarch *gdbarch = frame_unwind_arch (frame);
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ struct value *reg_val;
+
+ reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+ store_unsigned_integer (value_contents_writeable (reg_val),
+ register_size (gdbarch, regnum), byte_order, val);
+ return reg_val;
+}
+
+struct value *
+frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf)
+{
+ struct gdbarch *gdbarch = frame_unwind_arch (frame);
+ struct value *reg_val;
+
+ reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+ memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum));
+ return reg_val;
+}
+
+/* Return a value which indicates that FRAME's saved version of REGNUM
+ has a known constant (computed) value of ADDR. Convert the
+ CORE_ADDR to a target address if necessary. */
+
+struct value *
+frame_unwind_got_address (struct frame_info *frame, int regnum,
+ CORE_ADDR addr)
+{
+ struct gdbarch *gdbarch = frame_unwind_arch (frame);
+ struct value *reg_val;
+
+ reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+ pack_long (value_contents_writeable (reg_val),
+ register_type (gdbarch, regnum), addr);
+ return reg_val;
+}
+void _initialize_frame_unwind ();
void
-_initialize_frame_unwind (void)
+_initialize_frame_unwind ()
{
- frame_unwind_data = gdbarch_data_register_post_init (frame_unwind_init);
+ frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init);
}
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