/* Cache and manage frames for GDB, the GNU debugger.
- Copyright (C) 1986-2016 Free Software Foundation, Inc.
+ Copyright (C) 1986-2018 Free Software Foundation, Inc.
This file is part of GDB.
#include "frame-base.h"
#include "command.h"
#include "gdbcmd.h"
-#include "observer.h"
+#include "observable.h"
#include "objfiles.h"
#include "gdbthread.h"
#include "block.h"
#include "hashtab.h"
#include "valprint.h"
+/* The sentinel frame terminates the innermost end of the frame chain.
+ If unwound, it returns the information needed to construct an
+ innermost frame.
+
+ The current frame, which is the innermost frame, can be found at
+ sentinel_frame->prev. */
+
+static struct frame_info *sentinel_frame;
+
static struct frame_info *get_prev_frame_raw (struct frame_info *this_frame);
static const char *frame_stop_reason_symbol_string (enum unwind_stop_reason reason);
/* We keep a cache of stack frames, each of which is a "struct
frame_info". The innermost one gets allocated (in
- wait_for_inferior) each time the inferior stops; current_frame
+ wait_for_inferior) each time the inferior stops; sentinel_frame
points to it. Additional frames get allocated (in get_prev_frame)
as needed, and are chained through the next and prev fields. Any
time that the frame cache becomes invalid (most notably when we
struct program_space *pspace;
/* The frame's address space. */
- struct address_space *aspace;
+ const address_space *aspace;
/* The frame's low-level unwinder and corresponding cache. The
low-level unwinder is responsible for unwinding register values
fprintf_unfiltered (file, "!stack");
else if (id.stack_status == FID_STACK_UNAVAILABLE)
fprintf_unfiltered (file, "stack=<unavailable>");
+ else if (id.stack_status == FID_STACK_SENTINEL)
+ fprintf_unfiltered (file, "stack=<sentinel>");
else
fprintf_unfiltered (file, "stack=%s", hex_string (id.stack_addr));
fprintf_unfiltered (file, ",");
return frame;
}
+struct frame_info *
+skip_unwritable_frames (struct frame_info *frame)
+{
+ while (gdbarch_code_of_frame_writable (get_frame_arch (frame), frame) == 0)
+ {
+ frame = get_prev_frame (frame);
+ if (frame == NULL)
+ break;
+ }
+
+ return frame;
+}
+
/* See frame.h. */
struct frame_info *
if (fi == NULL)
return null_frame_id;
- gdb_assert (fi->this_id.p);
+ if (!fi->this_id.p)
+ {
+ int stashed;
+
+ /* If we haven't computed the frame id yet, then it must be that
+ this is the current frame. Compute it now, and stash the
+ result. The IDs of other frames are computed as soon as
+ they're created, in order to detect cycles. See
+ get_prev_frame_if_no_cycle. */
+ gdb_assert (fi->level == 0);
+
+ /* Compute. */
+ compute_frame_id (fi);
+
+ /* Since this is the first frame in the chain, this should
+ always succeed. */
+ stashed = frame_stash_add (fi);
+ gdb_assert (stashed);
+ }
+
return fi->this_id.value;
}
}
const struct frame_id null_frame_id = { 0 }; /* All zeros. */
+const struct frame_id sentinel_frame_id = { 0, 0, 0, FID_STACK_SENTINEL, 0, 1, 0 };
const struct frame_id outer_frame_id = { 0, 0, 0, FID_STACK_INVALID, 0, 1, 0 };
struct frame_id
if (!frame_id_p (id))
return NULL;
+ /* Check for the sentinel frame. */
+ if (frame_id_eq (id, sentinel_frame_id))
+ return sentinel_frame;
+
/* Try using the frame stash first. Finding it there removes the need
to perform the search by looping over all frames, which can be very
CPU-intensive if the number of frames is very high (the loop is O(n)
return REG_VALID;
}
-struct regcache *
+std::unique_ptr<readonly_detached_regcache>
frame_save_as_regcache (struct frame_info *this_frame)
{
- struct address_space *aspace = get_frame_address_space (this_frame);
- struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame),
- aspace);
- struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache);
+ std::unique_ptr<readonly_detached_regcache> regcache
+ (new readonly_detached_regcache (get_frame_arch (this_frame),
+ do_frame_register_read, this_frame));
- regcache_save (regcache, do_frame_register_read, this_frame);
- discard_cleanups (cleanups);
return regcache;
}
frame_pop (struct frame_info *this_frame)
{
struct frame_info *prev_frame;
- struct regcache *scratch;
- struct cleanup *cleanups;
if (get_frame_type (this_frame) == DUMMY_FRAME)
{
Save them in a scratch buffer so that there isn't a race between
trying to extract the old values from the current regcache while
at the same time writing new values into that same cache. */
- scratch = frame_save_as_regcache (prev_frame);
- cleanups = make_cleanup_regcache_xfree (scratch);
+ std::unique_ptr<readonly_detached_regcache> scratch
+ = frame_save_as_regcache (prev_frame);
/* FIXME: cagney/2003-03-16: It should be possible to tell the
target's register cache that it is about to be hit with a burst
Unfortunately, they don't implement it. Their lack of a formal
definition can lead to targets writing back bogus values
(arguably a bug in the target code mind). */
- /* Now copy those saved registers into the current regcache.
- Here, regcache_cpy() calls regcache_restore(). */
- regcache_cpy (get_current_regcache (), scratch);
- do_cleanups (cleanups);
+ /* Now copy those saved registers into the current regcache. */
+ get_current_regcache ()->restore (scratch.get ());
/* We've made right mess of GDB's local state, just discard
everything. */
*unavailablep = !value_entirely_available (value);
*lvalp = VALUE_LVAL (value);
*addrp = value_address (value);
- *realnump = VALUE_REGNUM (value);
+ if (*lvalp == lval_register)
+ *realnump = VALUE_REGNUM (value);
+ else
+ *realnump = -1;
if (bufferp)
{
/* Dispose of the new value. This prevents watchpoints from
trying to watch the saved frame pointer. */
release_value (value);
- value_free (value);
}
void
struct gdbarch *gdbarch = frame_unwind_arch (frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
int size = register_size (gdbarch, regnum);
- gdb_byte buf[MAX_REGISTER_SIZE];
+ struct value *value = frame_unwind_register_value (frame, regnum);
+
+ gdb_assert (value != NULL);
+
+ if (value_optimized_out (value))
+ {
+ throw_error (OPTIMIZED_OUT_ERROR,
+ _("Register %d was not saved"), regnum);
+ }
+ if (!value_entirely_available (value))
+ {
+ throw_error (NOT_AVAILABLE_ERROR,
+ _("Register %d is not available"), regnum);
+ }
+
+ LONGEST r = extract_signed_integer (value_contents_all (value), size,
+ byte_order);
- frame_unwind_register (frame, regnum, buf);
- return extract_signed_integer (buf, size, byte_order);
+ release_value (value);
+ return r;
}
LONGEST
struct gdbarch *gdbarch = frame_unwind_arch (frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
int size = register_size (gdbarch, regnum);
- gdb_byte buf[MAX_REGISTER_SIZE];
+ struct value *value = frame_unwind_register_value (frame, regnum);
+
+ gdb_assert (value != NULL);
+
+ if (value_optimized_out (value))
+ {
+ throw_error (OPTIMIZED_OUT_ERROR,
+ _("Register %d was not saved"), regnum);
+ }
+ if (!value_entirely_available (value))
+ {
+ throw_error (NOT_AVAILABLE_ERROR,
+ _("Register %d is not available"), regnum);
+ }
+
+ ULONGEST r = extract_unsigned_integer (value_contents_all (value), size,
+ byte_order);
- frame_unwind_register (frame, regnum, buf);
- return extract_unsigned_integer (buf, size, byte_order);
+ release_value (value);
+ return r;
}
ULONGEST
}
else
{
- gdb_byte buf[MAX_REGISTER_SIZE];
- enum lval_type lval;
- CORE_ADDR addr;
- int realnum;
+ struct value *value = frame_unwind_register_value (frame->next,
+ regnum);
+ gdb_assert (value != NULL);
+ *optimizedp = value_optimized_out (value);
+ *unavailablep = !value_entirely_available (value);
- frame_register (frame, regnum, optimizedp, unavailablep,
- &lval, &addr, &realnum, buf);
if (*optimizedp || *unavailablep)
- return 0;
- memcpy (myaddr, buf + offset, curr_len);
+ {
+ release_value (value);
+ return 0;
+ }
+ memcpy (myaddr, value_contents_all (value) + offset, curr_len);
+ release_value (value);
}
myaddr += curr_len;
}
else
{
- gdb_byte buf[MAX_REGISTER_SIZE];
-
- deprecated_frame_register_read (frame, regnum, buf);
- memcpy (buf + offset, myaddr, curr_len);
- put_frame_register (frame, regnum, buf);
+ struct value *value = frame_unwind_register_value (frame->next,
+ regnum);
+ gdb_assert (value != NULL);
+
+ memcpy ((char *) value_contents_writeable (value) + offset, myaddr,
+ curr_len);
+ put_frame_register (frame, regnum, value_contents_raw (value));
+ release_value (value);
}
myaddr += curr_len;
frame->level = -1;
frame->pspace = pspace;
- frame->aspace = get_regcache_aspace (regcache);
+ frame->aspace = regcache->aspace ();
/* Explicitly initialize the sentinel frame's cache. Provide it
with the underlying regcache. In the future additional
information, such as the frame's thread will be added. */
/* Link this frame back to itself. The frame is self referential
(the unwound PC is the same as the pc), so make it so. */
frame->next = frame;
- /* Make the sentinel frame's ID valid, but invalid. That way all
- comparisons with it should fail. */
+ /* The sentinel frame has a special ID. */
frame->this_id.p = 1;
- frame->this_id.value = null_frame_id;
+ frame->this_id.value = sentinel_frame_id;
if (frame_debug)
{
fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> ");
return frame;
}
-/* Info about the innermost stack frame (contents of FP register). */
-
-static struct frame_info *current_frame;
-
/* Cache for frame addresses already read by gdb. Valid only while
inferior is stopped. Control variables for the frame cache should
be local to this module. */
return data;
}
-/* Return the innermost (currently executing) stack frame. This is
- split into two functions. The function unwind_to_current_frame()
- is wrapped in catch exceptions so that, even when the unwind of the
- sentinel frame fails, the function still returns a stack frame. */
-
-static int
-unwind_to_current_frame (struct ui_out *ui_out, void *args)
-{
- struct frame_info *frame = get_prev_frame ((struct frame_info *) args);
-
- /* A sentinel frame can fail to unwind, e.g., because its PC value
- lands in somewhere like start. */
- if (frame == NULL)
- return 1;
- current_frame = frame;
- return 0;
-}
+static struct frame_info *get_prev_frame_always_1 (struct frame_info *this_frame);
struct frame_info *
get_current_frame (void)
{
+ struct frame_info *current_frame;
+
/* First check, and report, the lack of registers. Having GDB
report "No stack!" or "No memory" when the target doesn't even
have registers is very confusing. Besides, "printcmd.exp"
if (get_traceframe_number () < 0)
validate_registers_access ();
- if (current_frame == NULL)
- {
- struct frame_info *sentinel_frame =
- create_sentinel_frame (current_program_space, get_current_regcache ());
- if (catch_exceptions (current_uiout, unwind_to_current_frame,
- sentinel_frame, RETURN_MASK_ERROR) != 0)
- {
- /* Oops! Fake a current frame? Is this useful? It has a PC
- of zero, for instance. */
- current_frame = sentinel_frame;
- }
- }
+ if (sentinel_frame == NULL)
+ sentinel_frame =
+ create_sentinel_frame (current_program_space, get_current_regcache ());
+
+ /* Set the current frame before computing the frame id, to avoid
+ recursion inside compute_frame_id, in case the frame's
+ unwinder decides to do a symbol lookup (which depends on the
+ selected frame's block).
+
+ This call must always succeed. In particular, nothing inside
+ get_prev_frame_always_1 should try to unwind from the
+ sentinel frame, because that could fail/throw, and we always
+ want to leave with the current frame created and linked in --
+ we should never end up with the sentinel frame as outermost
+ frame. */
+ current_frame = get_prev_frame_always_1 (sentinel_frame);
+ gdb_assert (current_frame != NULL);
+
return current_frame;
}
return NULL;
}
+/* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
+ innermost (i.e. current) frame, return the sentinel frame. Thus,
+ unlike get_next_frame(), NULL will never be returned. */
+
+struct frame_info *
+get_next_frame_sentinel_okay (struct frame_info *this_frame)
+{
+ gdb_assert (this_frame != NULL);
+
+ /* Note that, due to the manner in which the sentinel frame is
+ constructed, this_frame->next still works even when this_frame
+ is the sentinel frame. But we disallow it here anyway because
+ calling get_next_frame_sentinel_okay() on the sentinel frame
+ is likely a coding error. */
+ gdb_assert (this_frame != sentinel_frame);
+
+ return this_frame->next;
+}
+
/* Observer for the target_changed event. */
static void
struct frame_info *fi;
/* Tear down all frame caches. */
- for (fi = current_frame; fi != NULL; fi = fi->prev)
+ for (fi = sentinel_frame; fi != NULL; fi = fi->prev)
{
if (fi->prologue_cache && fi->unwind->dealloc_cache)
fi->unwind->dealloc_cache (fi, fi->prologue_cache);
obstack_free (&frame_cache_obstack, 0);
obstack_init (&frame_cache_obstack);
- if (current_frame != NULL)
+ if (sentinel_frame != NULL)
annotate_frames_invalid ();
- current_frame = NULL; /* Invalidate cache */
+ sentinel_frame = NULL; /* Invalidate cache */
select_frame (NULL);
frame_stash_invalidate ();
if (frame_debug)
struct cleanup *prev_frame_cleanup;
prev_frame = get_prev_frame_raw (this_frame);
- if (prev_frame == NULL)
- return NULL;
+
+ /* Don't compute the frame id of the current frame yet. Unwinding
+ the sentinel frame can fail (e.g., if the thread is gone and we
+ can't thus read its registers). If we let the cycle detection
+ code below try to compute a frame ID, then an error thrown from
+ within the frame ID computation would result in the sentinel
+ frame as outermost frame, which is bogus. Instead, we'll compute
+ the current frame's ID lazily in get_frame_id. Note that there's
+ no point in doing cycle detection when there's only one frame, so
+ nothing is lost here. */
+ if (prev_frame->level == 0)
+ return prev_frame;
/* The cleanup will remove the previous frame that get_prev_frame_raw
linked onto THIS_FRAME. */
something should be calling get_selected_frame() or
get_current_frame(). */
gdb_assert (this_frame != NULL);
+
+ /* If this_frame is the current frame, then compute and stash
+ its frame id prior to fetching and computing the frame id of the
+ previous frame. Otherwise, the cycle detection code in
+ get_prev_frame_if_no_cycle() will not work correctly. When
+ get_frame_id() is called later on, an assertion error will
+ be triggered in the event of a cycle between the current
+ frame and its previous frame. */
+ if (this_frame->level == 0)
+ get_frame_id (this_frame);
+
frame_pc_p = get_frame_pc_if_available (this_frame, &frame_pc);
/* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
return get_prev_frame_always (this_frame);
}
+struct frame_id
+get_prev_frame_id_by_id (struct frame_id id)
+{
+ struct frame_id prev_id;
+ struct frame_info *frame;
+
+ frame = frame_find_by_id (id);
+
+ if (frame != NULL)
+ prev_id = get_frame_id (get_prev_frame (frame));
+ else
+ prev_id = null_frame_id;
+
+ return prev_id;
+}
+
CORE_ADDR
get_frame_pc (struct frame_info *frame)
{
return 1;
}
-void
-find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
+symtab_and_line
+find_frame_sal (frame_info *frame)
{
struct frame_info *next_frame;
int notcurrent;
/* If frame is inline, it certainly has symbols. */
gdb_assert (sym);
- init_sal (sal);
+
+ symtab_and_line sal;
if (SYMBOL_LINE (sym) != 0)
{
- sal->symtab = symbol_symtab (sym);
- sal->line = SYMBOL_LINE (sym);
+ sal.symtab = symbol_symtab (sym);
+ sal.line = SYMBOL_LINE (sym);
}
else
/* If the symbol does not have a location, we don't know where
the call site is. Do not pretend to. This is jarring, but
we can't do much better. */
- sal->pc = get_frame_pc (frame);
-
- sal->pspace = get_frame_program_space (frame);
+ sal.pc = get_frame_pc (frame);
- return;
+ sal.pspace = get_frame_program_space (frame);
+ return sal;
}
/* If FRAME is not the innermost frame, that normally means that
instruction/line, consequently, for such cases, want to get the
line containing fi->pc. */
if (!get_frame_pc_if_available (frame, &pc))
- {
- init_sal (sal);
- return;
- }
+ return {};
notcurrent = (pc != get_frame_address_in_block (frame));
- (*sal) = find_pc_line (pc, notcurrent);
+ return find_pc_line (pc, notcurrent);
}
/* Per "frame.h", return the ``address'' of the frame. Code should
return this_frame->pspace;
}
-struct address_space *
+const address_space *
get_frame_address_space (struct frame_info *frame)
{
return frame->aspace;
/* Clean up after a failed (wrong unwinder) attempt to unwind past
FRAME. */
-static void
-frame_cleanup_after_sniffer (void *arg)
+void
+frame_cleanup_after_sniffer (struct frame_info *frame)
{
- struct frame_info *frame = (struct frame_info *) arg;
-
/* The sniffer should not allocate a prologue cache if it did not
match this frame. */
gdb_assert (frame->prologue_cache == NULL);
}
/* Set FRAME's unwinder temporarily, so that we can call a sniffer.
- Return a cleanup which should be called if unwinding fails, and
- discarded if it succeeds. */
+ If sniffing fails, the caller should be sure to call
+ frame_cleanup_after_sniffer. */
-struct cleanup *
+void
frame_prepare_for_sniffer (struct frame_info *frame,
const struct frame_unwind *unwind)
{
gdb_assert (frame->unwind == NULL);
frame->unwind = unwind;
- return make_cleanup (frame_cleanup_after_sniffer, frame);
}
-extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
-
static struct cmd_list_element *set_backtrace_cmdlist;
static struct cmd_list_element *show_backtrace_cmdlist;
static void
-set_backtrace_cmd (char *args, int from_tty)
+set_backtrace_cmd (const char *args, int from_tty)
{
help_list (set_backtrace_cmdlist, "set backtrace ", all_commands,
gdb_stdout);
}
static void
-show_backtrace_cmd (char *args, int from_tty)
+show_backtrace_cmd (const char *args, int from_tty)
{
cmd_show_list (show_backtrace_cmdlist, from_tty, "");
}
frame_stash_create ();
- observer_attach_target_changed (frame_observer_target_changed);
+ gdb::observers::target_changed.attach (frame_observer_target_changed);
add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
Set backtrace specific variables.\n\
projects / deliverable / binutils-gdb.git / blobdiff