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- /* Definitions for frame unwinder, for GDB, the GNU debugger.
- Copyright (C) 2003-2022 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 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 "frame.h"
- #include "frame-unwind.h"
- #include "dummy-frame.h"
- #include "inline-frame.h"
- #include "value.h"
- #include "regcache.h"
- #include "gdbsupport/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
- {
- struct frame_unwind_table_entry *list;
- /* The head of the OSABI part of the search list. */
- struct frame_unwind_table_entry **osabi_head;
- };
- /* 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)
- {
- *link = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
- (*link)->unwinder = unwinder;
- return &(*link)->next;
- }
- static void *
- frame_unwind_init (struct obstack *obstack)
- {
- 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_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)
- {
- int res = 0;
- unsigned int entry_generation = get_frame_cache_generation ();
- frame_prepare_for_sniffer (this_frame, unwinder);
- try
- {
- frame_debug_printf ("trying unwinder \"%s\"", unwinder->name);
- res = unwinder->sniffer (unwinder, this_frame, this_cache);
- }
- catch (const gdb_exception &ex)
- {
- frame_debug_printf ("caught exception: %s", ex.message->c_str ());
- /* Catch all exceptions, caused by either interrupt or error.
- Reset *THIS_CACHE, unless something reinitialized the frame
- cache meanwhile, in which case THIS_FRAME/THIS_CACHE are now
- dangling. */
- if (get_frame_cache_generation () == entry_generation)
- {
- *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;
- }
- if (res)
- {
- frame_debug_printf ("yes");
- return 1;
- }
- else
- {
- frame_debug_printf ("no");
- /* 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");
- }
- /* 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)
- {
- FRAME_SCOPED_DEBUG_ENTER_EXIT;
- frame_debug_printf ("this_frame=%d", frame_relative_level (this_frame));
- 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);
- return allocate_optimized_out_value (type);
- }
- /* 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).data (),
- register_size (gdbarch, regnum), byte_order, val);
- return reg_val;
- }
- struct value *
- frame_unwind_got_bytes (struct frame_info *frame, int regnum, const 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).data (), 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).data (),
- register_type (gdbarch, regnum), addr);
- return reg_val;
- }
- void _initialize_frame_unwind ();
- void
- _initialize_frame_unwind ()
- {
- frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init);
- }
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