/* Definitions for frame unwinder, for GDB, the GNU debugger.
- Copyright (C) 2003, 2004, 2007, 2008, 2009 Free Software Foundation, Inc.
+ Copyright (C) 2003-2020 Free Software Foundation, Inc.
This file is part of GDB.
#include "inline-frame.h"
#include "value.h"
#include "regcache.h"
-
-#include "gdb_assert.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 **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. */
- table->list = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
- table->list->unwinder = dummy_frame_unwind;
- table->list->next = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
- table->list->next->unwinder = inline_frame_unwind;
+ 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 = &table->list->next->next;
+ table->osabi_head = link;
return table;
}
frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
const struct frame_unwind *unwinder)
{
- struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
+ 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. */
frame_unwind_append_unwinder (struct gdbarch *gdbarch,
const struct frame_unwind *unwinder)
{
- struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
+ 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. */
(*ip)->unwinder = unwinder;
}
-const struct frame_unwind *
-frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache)
+/* 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 i;
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
- struct frame_unwind_table_entry *entry;
- struct cleanup *old_cleanup;
- for (entry = table->list; entry != NULL; entry = entry->next)
+ int res = 0;
+
+ frame_prepare_for_sniffer (this_frame, unwinder);
+
+ try
+ {
+ res = unwinder->sniffer (unwinder, this_frame, this_cache);
+ }
+ catch (const gdb_exception &ex)
{
- struct cleanup *old_cleanup;
+ /* Catch all exceptions, caused by either interrupt or error.
+ Reset *THIS_CACHE. */
+ *this_cache = NULL;
+ frame_cleanup_after_sniffer (this_frame);
- old_cleanup = frame_prepare_for_sniffer (this_frame, entry->unwinder);
- if (entry->unwinder->sniffer (entry->unwinder, this_frame,
- this_cache))
+ if (ex.error == NOT_AVAILABLE_ERROR)
{
- discard_cleanups (old_cleanup);
- return entry->unwinder;
+ /* 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;
}
- do_cleanups (old_cleanup);
+ throw;
+ }
+
+ 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");
+}
+
+/* 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"));
}
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. */
frame_unwind_got_optimized (struct frame_info *frame, int regnum)
{
struct gdbarch *gdbarch = frame_unwind_arch (frame);
- struct value *reg_val;
-
- reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
- set_value_optimized_out (reg_val, 1);
- return reg_val;
+ 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)
+frame_unwind_got_register (struct frame_info *frame,
+ int regnum, int new_regnum)
{
return value_of_register_lazy (frame, new_regnum);
}
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);
- return 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
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), val);
+ register_size (gdbarch, regnum), byte_order, val);
return reg_val;
}
return reg_val;
}
-extern initialize_file_ftype _initialize_frame_unwind; /* -Wmissing-prototypes */
-
+void _initialize_frame_unwind ();
void
-_initialize_frame_unwind (void)
+_initialize_frame_unwind ()
{
frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init);
}
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