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btrace, gdbserver: read branch trace incrementally

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Read branch trace data incrementally and extend the current trace rather than
discarding it and reading the entire trace buffer each time.

If the branch trace buffer overflowed, we can't extend the current trace so we
discard it and start anew by reading the entire branch trace buffer.

2014-01-16  Markus Metzger  <markus.t.metzger@intel.com>

	* common/linux-btrace.c (perf_event_read_bts, linux_read_btrace):
	Support delta reads.
	(linux_disable_btrace): Change return type.
	* common/linux-btrace.h (linux_read_btrace): Change parameters
	and return type to allow error reporting.  Update users.
	(linux_disable_btrace): Change return type.  Update users.
	* common/btrace-common.h (btrace_read_type) <BTRACE_READ_DELTA>:
	New.
	(btrace_error): New.
	(btrace_block) <begin>: Comment on BEGIN == 0.
	* btrace.c (btrace_compute_ftrace): Start from the end of
	the current trace.
	(btrace_stitch_trace, btrace_clear_history): New.
	(btrace_fetch): Read delta trace, return if replaying.
	(btrace_clear): Move clear history code to btrace_clear_history.
	(parse_xml_btrace): Throw an error if parsing failed.
	* target.h (struct target_ops) <to_read_btrace>: Change parameters
	and return type to allow error reporting.
	(target_read_btrace): Change parameters and return type to allow
	error reporting.
	* target.c (target_read_btrace): Update.
	* remote.c (remote_read_btrace): Support delta reads.  Pass
	errors on.
	* NEWS: Announce it.

gdbserver/
	* target.h (target_ops) <read_btrace>: Change parameters and
	return type to allow error reporting.
	* server.c (handle_qxfer_btrace): Support delta reads.  Pass
	trace reading errors on.
	* linux-low.c (linux_low_read_btrace): Pass trace reading
	errors on.
	(linux_low_disable_btrace): New.
This commit is contained in:
Markus Metzger 2013-06-03 15:39:35 +02:00
parent 0b722aec57
commit 969c39fbcd
16 changed files with 369 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
gdb/ChangeLog
View File

@ -1,3 +1,30 @@
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* common/linux-btrace.c (perf_event_read_bts, linux_read_btrace):
Support delta reads.
(linux_disable_btrace): Change return type.
* common/linux-btrace.h (linux_read_btrace): Change parameters
and return type to allow error reporting. Update users.
(linux_disable_btrace): Change return type. Update users.
* common/btrace-common.h (btrace_read_type) <BTRACE_READ_DELTA>:
New.
(btrace_error): New.
(btrace_block) <begin>: Comment on BEGIN == 0.
* btrace.c (btrace_compute_ftrace): Start from the end of
the current trace.
(btrace_stitch_trace, btrace_clear_history): New.
(btrace_fetch): Read delta trace, return if replaying.
(btrace_clear): Move clear history code to btrace_clear_history.
(parse_xml_btrace): Throw an error if parsing failed.
* target.h (struct target_ops) <to_read_btrace>: Change parameters
and return type to allow error reporting.
(target_read_btrace): Change parameters and return type to allow
error reporting.
* target.c (target_read_btrace): Update.
* remote.c (remote_read_btrace): Support delta reads. Pass
errors on.
* NEWS: Announce it.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* record.h (record_btrace_frame_unwind)

6
gdb/NEWS
View File

@ -22,6 +22,12 @@
For locations inside the execution trace, the back trace is computed
based on the information stored in the execution trace.
* New remote packets
qXfer:btrace:read's annex
The qXfer:btrace:read packet supports a new annex 'delta' to read
branch trace incrementally.
*** Changes in GDB 7.7
* Improved support for process record-replay and reverse debugging on

6
gdb/amd64-linux-nat.c
View File

@ -1173,10 +1173,10 @@ amd64_linux_enable_btrace (ptid_t ptid)
static void
amd64_linux_disable_btrace (struct btrace_target_info *tinfo)
{
int errcode = linux_disable_btrace (tinfo);
enum btrace_error errcode = linux_disable_btrace (tinfo);
if (errcode != 0)
error (_("Could not disable branch tracing: %s."), safe_strerror (errcode));
if (errcode != BTRACE_ERR_NONE)
error (_("Could not disable branch tracing."));
}
/* Teardown branch tracing. */

156
gdb/btrace.c
View File

@ -599,9 +599,9 @@ btrace_compute_ftrace (struct btrace_thread_info *btinfo,
DEBUG ("compute ftrace");
gdbarch = target_gdbarch ();
begin = NULL;
end = NULL;
level = INT_MAX;
begin = btinfo->begin;
end = btinfo->end;
level = begin != NULL ? -btinfo->level : INT_MAX;
blk = VEC_length (btrace_block_s, btrace);
while (blk != 0)
@ -728,27 +728,158 @@ btrace_teardown (struct thread_info *tp)
btrace_clear (tp);
}
/* Adjust the block trace in order to stitch old and new trace together.
BTRACE is the new delta trace between the last and the current stop.
BTINFO is the old branch trace until the last stop.
May modify BTRACE as well as the existing trace in BTINFO.
Return 0 on success, -1 otherwise. */
static int
btrace_stitch_trace (VEC (btrace_block_s) **btrace,
const struct btrace_thread_info *btinfo)
{
struct btrace_function *last_bfun;
struct btrace_insn *last_insn;
btrace_block_s *first_new_block;
/* If we don't have trace, there's nothing to do. */
if (VEC_empty (btrace_block_s, *btrace))
return 0;
last_bfun = btinfo->end;
gdb_assert (last_bfun != NULL);
/* Beware that block trace starts with the most recent block, so the
chronologically first block in the new trace is the last block in
the new trace's block vector. */
first_new_block = VEC_last (btrace_block_s, *btrace);
last_insn = VEC_last (btrace_insn_s, last_bfun->insn);
/* If the current PC at the end of the block is the same as in our current
trace, there are two explanations:
1. we executed the instruction and some branch brought us back.
2. we have not made any progress.
In the first case, the delta trace vector should contain at least two
entries.
In the second case, the delta trace vector should contain exactly one
entry for the partial block containing the current PC. Remove it. */
if (first_new_block->end == last_insn->pc
&& VEC_length (btrace_block_s, *btrace) == 1)
{
VEC_pop (btrace_block_s, *btrace);
return 0;
}
DEBUG ("stitching %s to %s", ftrace_print_insn_addr (last_insn),
core_addr_to_string_nz (first_new_block->end));
/* Do a simple sanity check to make sure we don't accidentally end up
with a bad block. This should not occur in practice. */
if (first_new_block->end < last_insn->pc)
{
warning (_("Error while trying to read delta trace. Falling back to "
"a full read."));
return -1;
}
/* We adjust the last block to start at the end of our current trace. */
gdb_assert (first_new_block->begin == 0);
first_new_block->begin = last_insn->pc;
/* We simply pop the last insn so we can insert it again as part of
the normal branch trace computation.
Since instruction iterators are based on indices in the instructions
vector, we don't leave any pointers dangling. */
DEBUG ("pruning insn at %s for stitching",
ftrace_print_insn_addr (last_insn));
VEC_pop (btrace_insn_s, last_bfun->insn);
/* The instructions vector may become empty temporarily if this has
been the only instruction in this function segment.
This violates the invariant but will be remedied shortly by
btrace_compute_ftrace when we add the new trace. */
return 0;
}
/* Clear the branch trace histories in BTINFO. */
static void
btrace_clear_history (struct btrace_thread_info *btinfo)
{
xfree (btinfo->insn_history);
xfree (btinfo->call_history);
xfree (btinfo->replay);
btinfo->insn_history = NULL;
btinfo->call_history = NULL;
btinfo->replay = NULL;
}
/* See btrace.h. */
void
btrace_fetch (struct thread_info *tp)
{
struct btrace_thread_info *btinfo;
struct btrace_target_info *tinfo;
VEC (btrace_block_s) *btrace;
struct cleanup *cleanup;
int errcode;
DEBUG ("fetch thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
btrace = NULL;
btinfo = &tp->btrace;
if (btinfo->target == NULL)
tinfo = btinfo->target;
if (tinfo == NULL)
return;
/* There's no way we could get new trace while replaying.
On the other hand, delta trace would return a partial record with the
current PC, which is the replay PC, not the last PC, as expected. */
if (btinfo->replay != NULL)
return;
btrace = target_read_btrace (btinfo->target, BTRACE_READ_NEW);
cleanup = make_cleanup (VEC_cleanup (btrace_block_s), &btrace);
/* Let's first try to extend the trace we already have. */
if (btinfo->end != NULL)
{
errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_DELTA);
if (errcode == 0)
{
/* Success. Let's try to stitch the traces together. */
errcode = btrace_stitch_trace (&btrace, btinfo);
}
else
{
/* We failed to read delta trace. Let's try to read new trace. */
errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_NEW);
/* If we got any new trace, discard what we have. */
if (errcode == 0 && !VEC_empty (btrace_block_s, btrace))
btrace_clear (tp);
}
/* If we were not able to read the trace, we start over. */
if (errcode != 0)
{
btrace_clear (tp);
errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_ALL);
}
}
else
errcode = target_read_btrace (&btrace, tinfo, BTRACE_READ_ALL);
/* If we were not able to read the branch trace, signal an error. */
if (errcode != 0)
error (_("Failed to read branch trace."));
/* Compute the trace, provided we have any. */
if (!VEC_empty (btrace_block_s, btrace))
{
btrace_clear (tp);
btrace_clear_history (btinfo);
btrace_compute_ftrace (btinfo, btrace);
}
@ -783,13 +914,7 @@ btrace_clear (struct thread_info *tp)
btinfo->begin = NULL;
btinfo->end = NULL;
xfree (btinfo->insn_history);
xfree (btinfo->call_history);
xfree (btinfo->replay);
btinfo->insn_history = NULL;
btinfo->call_history = NULL;
btinfo->replay = NULL;
btrace_clear_history (btinfo);
}
/* See btrace.h. */
@ -881,10 +1006,7 @@ parse_xml_btrace (const char *buffer)
errcode = gdb_xml_parse_quick (_("btrace"), "btrace.dtd", btrace_elements,
buffer, &btrace);
if (errcode != 0)
{
do_cleanups (cleanup);
return NULL;
}
error (_("Error parsing branch trace."));
/* Keep parse results. */
discard_cleanups (cleanup);

27
gdb/common/btrace-common.h
View File

@ -42,7 +42,9 @@
asynchronous, e.g. interrupts. */
struct btrace_block
{
/* The address of the first byte of the first instruction in the block. */
/* The address of the first byte of the first instruction in the block.
The address may be zero if we do not know the beginning of this block,
such as for the first block in a delta trace. */
CORE_ADDR begin;
/* The address of the first byte of the last instruction in the block. */
@ -67,7 +69,28 @@ enum btrace_read_type
BTRACE_READ_ALL,
/* Send all available trace, if it changed. */
BTRACE_READ_NEW
BTRACE_READ_NEW,
/* Send the trace since the last request. This will fail if the trace
buffer overflowed. */
BTRACE_READ_DELTA
};
/* Enumeration of btrace errors. */
enum btrace_error
{
/* No error. Everything is OK. */
BTRACE_ERR_NONE,
/* An unknown error. */
BTRACE_ERR_UNKNOWN,
/* Branch tracing is not supported on this system. */
BTRACE_ERR_NOT_SUPPORTED,
/* The branch trace buffer overflowed; no delta read possible. */
BTRACE_ERR_OVERFLOW
};
#endif /* BTRACE_COMMON_H */

95
gdb/common/linux-btrace.c
View File

@ -172,11 +172,11 @@ perf_event_sample_ok (const struct perf_event_sample *sample)
static VEC (btrace_block_s) *
perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
const uint8_t *end, const uint8_t *start)
const uint8_t *end, const uint8_t *start, size_t size)
{
VEC (btrace_block_s) *btrace = NULL;
struct perf_event_sample sample;
size_t read = 0, size = (end - begin);
size_t read = 0;
struct btrace_block block = { 0, 0 };
struct regcache *regcache;
@ -252,6 +252,13 @@ perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
block.end = psample->bts.from;
}
/* Push the last block (i.e. the first one of inferior execution), as well.
We don't know where it ends, but we know where it starts. If we're
reading delta trace, we can fill in the start address later on.
Otherwise we will prune it. */
block.begin = 0;
VEC_safe_push (btrace_block_s, btrace, &block);
return btrace;
}
@ -476,7 +483,7 @@ linux_enable_btrace (ptid_t ptid)
/* See linux-btrace.h. */
int
enum btrace_error
linux_disable_btrace (struct btrace_target_info *tinfo)
{
int errcode;
@ -484,12 +491,12 @@ linux_disable_btrace (struct btrace_target_info *tinfo)
errno = 0;
errcode = munmap (tinfo->buffer, perf_event_mmap_size (tinfo));
if (errcode != 0)
return errno;
return BTRACE_ERR_UNKNOWN;
close (tinfo->file);
xfree (tinfo);
return 0;
return BTRACE_ERR_NONE;
}
/* Check whether the branch trace has changed. */
@ -504,21 +511,24 @@ linux_btrace_has_changed (struct btrace_target_info *tinfo)
/* See linux-btrace.h. */
VEC (btrace_block_s) *
linux_read_btrace (struct btrace_target_info *tinfo,
enum btrace_error
linux_read_btrace (VEC (btrace_block_s) **btrace,
struct btrace_target_info *tinfo,
enum btrace_read_type type)
{
VEC (btrace_block_s) *btrace = NULL;
volatile struct perf_event_mmap_page *header;
const uint8_t *begin, *end, *start;
unsigned long data_head, retries = 5;
size_t buffer_size;
unsigned long data_head, data_tail, retries = 5;
size_t buffer_size, size;
/* For delta reads, we return at least the partial last block containing
the current PC. */
if (type == BTRACE_READ_NEW && !linux_btrace_has_changed (tinfo))
return NULL;
return BTRACE_ERR_NONE;
header = perf_event_header (tinfo);
buffer_size = perf_event_buffer_size (tinfo);
data_tail = tinfo->data_head;
/* We may need to retry reading the trace. See below. */
while (retries--)
@ -526,22 +536,44 @@ linux_read_btrace (struct btrace_target_info *tinfo,
data_head = header->data_head;
/* Delete any leftover trace from the previous iteration. */
VEC_free (btrace_block_s, btrace);
VEC_free (btrace_block_s, *btrace);
/* If there's new trace, let's read it. */
if (data_head != tinfo->data_head)
if (type == BTRACE_READ_DELTA)
{
/* Data_head keeps growing; the buffer itself is circular. */
begin = perf_event_buffer_begin (tinfo);
start = begin + data_head % buffer_size;
/* Determine the number of bytes to read and check for buffer
overflows. */
if (data_head <= buffer_size)
end = start;
else
end = perf_event_buffer_end (tinfo);
/* Check for data head overflows. We might be able to recover from
those but they are very unlikely and it's not really worth the
effort, I think. */
if (data_head < data_tail)
return BTRACE_ERR_OVERFLOW;
btrace = perf_event_read_bts (tinfo, begin, end, start);
/* If the buffer is smaller than the trace delta, we overflowed. */
size = data_head - data_tail;
if (buffer_size < size)
return BTRACE_ERR_OVERFLOW;
}
else
{
/* Read the entire buffer. */
size = buffer_size;
/* Adjust the size if the buffer has not overflowed, yet. */
if (data_head < size)
size = data_head;
}
/* Data_head keeps growing; the buffer itself is circular. */
begin = perf_event_buffer_begin (tinfo);
start = begin + data_head % buffer_size;
if (data_head <= buffer_size)
end = start;
else
end = perf_event_buffer_end (tinfo);
*btrace = perf_event_read_bts (tinfo, begin, end, start, size);
/* The stopping thread notifies its ptracer before it is scheduled out.
On multi-core systems, the debugger might therefore run while the
@ -554,7 +586,13 @@ linux_read_btrace (struct btrace_target_info *tinfo,
tinfo->data_head = data_head;
return btrace;
/* Prune the incomplete last block (i.e. the first one of inferior execution)
if we're not doing a delta read. There is no way of filling in its zeroed
BEGIN element. */
if (!VEC_empty (btrace_block_s, *btrace) && type != BTRACE_READ_DELTA)
VEC_pop (btrace_block_s, *btrace);
return BTRACE_ERR_NONE;
}
#else /* !HAVE_LINUX_PERF_EVENT_H */
@ -577,19 +615,20 @@ linux_enable_btrace (ptid_t ptid)
/* See linux-btrace.h. */
int
enum btrace_error
linux_disable_btrace (struct btrace_target_info *tinfo)
{
return ENOSYS;
return BTRACE_ERR_NOT_SUPPORTED;
}
/* See linux-btrace.h. */
VEC (btrace_block_s) *
linux_read_btrace (struct btrace_target_info *tinfo,
enum btrace_error
linux_read_btrace (VEC (btrace_block_s) **btrace,
struct btrace_target_info *tinfo,
enum btrace_read_type type)
{
return NULL;
return BTRACE_ERR_NOT_SUPPORTED;
}
#endif /* !HAVE_LINUX_PERF_EVENT_H */

15
gdb/common/linux-btrace.h
View File

@ -61,17 +61,18 @@ struct btrace_target_info
int ptr_bits;
};
/* Check whether branch tracing is supported. */
/* See to_supports_btrace in target.h. */
extern int linux_supports_btrace (void);
/* Enable branch tracing for @ptid. */
/* See to_enable_btrace in target.h. */
extern struct btrace_target_info *linux_enable_btrace (ptid_t ptid);
/* Disable branch tracing and deallocate @tinfo. */
extern int linux_disable_btrace (struct btrace_target_info *tinfo);
/* See to_disable_btrace in target.h. */
extern enum btrace_error linux_disable_btrace (struct btrace_target_info *ti);
/* Read branch trace data. */
extern VEC (btrace_block_s) *linux_read_btrace (struct btrace_target_info *,
enum btrace_read_type);
/* See to_read_btrace in target.h. */
extern enum btrace_error linux_read_btrace (VEC (btrace_block_s) **btrace,
struct btrace_target_info *btinfo,
enum btrace_read_type type);
#endif /* LINUX_BTRACE_H */

8
gdb/doc/gdb.texinfo
View File

@ -39978,6 +39978,14 @@ Returns all available branch trace.
@item new
Returns all available branch trace if the branch trace changed since
the last read request.
@item delta
Returns the new branch trace since the last read request. Adds a new
block to the end of the trace that begins at zero and ends at the source
location of the first branch in the trace buffer. This extra block is
used to stitch traces together.
If the trace buffer overflowed, returns an error indicating the overflow.
@end table
This packet is not probed by default; the remote stub must request it

10
gdb/gdbserver/ChangeLog
View File

@ -1,3 +1,13 @@
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* target.h (target_ops) <read_btrace>: Change parameters and
return type to allow error reporting.
* server.c (handle_qxfer_btrace): Support delta reads. Pass
trace reading errors on.
* linux-low.c (linux_low_read_btrace): Pass trace reading
errors on.
(linux_low_disable_btrace): New.
2014-01-15 Doug Evans <dje@google.com>
* inferiors.c (thread_id_to_gdb_id): Delete.

36
gdb/gdbserver/linux-low.c
View File

@ -5705,7 +5705,7 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
#ifdef HAVE_LINUX_BTRACE
/* Enable branch tracing. */
/* See to_enable_btrace target method. */
static struct btrace_target_info *
linux_low_enable_btrace (ptid_t ptid)
@ -5725,17 +5725,39 @@ linux_low_enable_btrace (ptid_t ptid)
return tinfo;
}
/* Read branch trace data as btrace xml document. */
/* See to_disable_btrace target method. */
static void
static int
linux_low_disable_btrace (struct btrace_target_info *tinfo)
{
enum btrace_error err;
err = linux_disable_btrace (tinfo);
return (err == BTRACE_ERR_NONE ? 0 : -1);
}
/* See to_read_btrace target method. */
static int
linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer,
int type)
{
VEC (btrace_block_s) *btrace;
struct btrace_block *block;
enum btrace_error err;
int i;
btrace = linux_read_btrace (tinfo, type);
btrace = NULL;
err = linux_read_btrace (&btrace, tinfo, type);
if (err != BTRACE_ERR_NONE)
{
if (err == BTRACE_ERR_OVERFLOW)
buffer_grow_str0 (buffer, "E.Overflow.");
else
buffer_grow_str0 (buffer, "E.Generic Error.");
return -1;
}
buffer_grow_str (buffer, "<!DOCTYPE btrace SYSTEM \"btrace.dtd\">\n");
buffer_grow_str (buffer, "<btrace version=\"1.0\">\n");
@ -5744,9 +5766,11 @@ linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer,
buffer_xml_printf (buffer, "<block begin=\"0x%s\" end=\"0x%s\"/>\n",
paddress (block->begin), paddress (block->end));
buffer_grow_str (buffer, "</btrace>\n");
buffer_grow_str0 (buffer, "</btrace>\n");
VEC_free (btrace_block_s, btrace);
return 0;
}
#endif /* HAVE_LINUX_BTRACE */
@ -5819,7 +5843,7 @@ static struct target_ops linux_target_ops = {
#ifdef HAVE_LINUX_BTRACE
linux_supports_btrace,
linux_low_enable_btrace,
linux_disable_btrace,
linux_low_disable_btrace,
linux_low_read_btrace,
#else
NULL,

11
gdb/gdbserver/server.c
View File

@ -1348,7 +1348,7 @@ handle_qxfer_btrace (const char *annex,
{
static struct buffer cache;
struct thread_info *thread;
int type;
int type, result;
if (the_target->read_btrace == NULL || writebuf != NULL)
return -2;
@ -1380,6 +1380,8 @@ handle_qxfer_btrace (const char *annex,
type = BTRACE_READ_ALL;
else if (strcmp (annex, "new") == 0)
type = BTRACE_READ_NEW;
else if (strcmp (annex, "delta") == 0)
type = BTRACE_READ_DELTA;
else
{
strcpy (own_buf, "E.Bad annex.");
@ -1390,7 +1392,12 @@ handle_qxfer_btrace (const char *annex,
{
buffer_free (&cache);
target_read_btrace (thread->btrace, &cache, type);
result = target_read_btrace (thread->btrace, &cache, type);
if (result != 0)
{
memcpy (own_buf, cache.buffer, cache.used_size);
return -3;
}
}
else if (offset > cache.used_size)
{

9
gdb/gdbserver/target.h
View File

@ -356,12 +356,15 @@ struct target_ops
information struct for reading and for disabling branch trace. */
struct btrace_target_info *(*enable_btrace) (ptid_t ptid);
/* Disable branch tracing. */
/* Disable branch tracing.
Returns zero on success, non-zero otherwise. */
int (*disable_btrace) (struct btrace_target_info *tinfo);
/* Read branch trace data into buffer. We use an int to specify the type
to break a cyclic dependency. */
void (*read_btrace) (struct btrace_target_info *, struct buffer *, int type);
to break a cyclic dependency.
Return 0 on success; print an error message into BUFFER and return -1,
otherwise. */
int (*read_btrace) (struct btrace_target_info *, struct buffer *, int type);
/* Return true if target supports range stepping. */
int (*supports_range_stepping) (void);

6
gdb/i386-linux-nat.c
View File

@ -1084,10 +1084,10 @@ i386_linux_enable_btrace (ptid_t ptid)
static void
i386_linux_disable_btrace (struct btrace_target_info *tinfo)
{
int errcode = linux_disable_btrace (tinfo);
enum btrace_error errcode = linux_disable_btrace (tinfo);
if (errcode != 0)
error (_("Could not disable branch tracing: %s."), safe_strerror (errcode));
if (errcode != BTRACE_ERR_NONE)
error (_("Could not disable branch tracing."));
}
/* Teardown branch tracing. */

23
gdb/remote.c
View File

@ -11489,13 +11489,14 @@ remote_teardown_btrace (struct btrace_target_info *tinfo)
/* Read the branch trace. */
static VEC (btrace_block_s) *
remote_read_btrace (struct btrace_target_info *tinfo,
static enum btrace_error
remote_read_btrace (VEC (btrace_block_s) **btrace,
struct btrace_target_info *tinfo,
enum btrace_read_type type)
{
struct packet_config *packet = &remote_protocol_packets[PACKET_qXfer_btrace];
struct remote_state *rs = get_remote_state ();
VEC (btrace_block_s) *btrace = NULL;
struct cleanup *cleanup;
const char *annex;
char *xml;
@ -11514,6 +11515,9 @@ remote_read_btrace (struct btrace_target_info *tinfo,
case BTRACE_READ_NEW:
annex = "new";
break;
case BTRACE_READ_DELTA:
annex = "delta";
break;
default:
internal_error (__FILE__, __LINE__,
_("Bad branch tracing read type: %u."),
@ -11522,15 +11526,14 @@ remote_read_btrace (struct btrace_target_info *tinfo,
xml = target_read_stralloc (&current_target,
TARGET_OBJECT_BTRACE, annex);
if (xml != NULL)
{
struct cleanup *cleanup = make_cleanup (xfree, xml);
if (xml == NULL)
return BTRACE_ERR_UNKNOWN;
btrace = parse_xml_btrace (xml);
do_cleanups (cleanup);
}
cleanup = make_cleanup (xfree, xml);
*btrace = parse_xml_btrace (xml);
do_cleanups (cleanup);
return btrace;
return BTRACE_ERR_NONE;
}
static int

9
gdb/target.c
View File

@ -4232,18 +4232,19 @@ target_teardown_btrace (struct btrace_target_info *btinfo)
/* See target.h. */
VEC (btrace_block_s) *
target_read_btrace (struct btrace_target_info *btinfo,
enum btrace_error
target_read_btrace (VEC (btrace_block_s) **btrace,
struct btrace_target_info *btinfo,
enum btrace_read_type type)
{
struct target_ops *t;
for (t = current_target.beneath; t != NULL; t = t->beneath)
if (t->to_read_btrace != NULL)
return t->to_read_btrace (btinfo, type);
return t->to_read_btrace (btrace, btinfo, type);
tcomplain ();
return NULL;
return BTRACE_ERR_NOT_SUPPORTED;
}
/* See target.h. */

15
gdb/target.h
View File

@ -839,9 +839,13 @@ struct target_ops
be attempting to talk to a remote target. */
void (*to_teardown_btrace) (struct btrace_target_info *tinfo);
/* Read branch trace data. */
VEC (btrace_block_s) *(*to_read_btrace) (struct btrace_target_info *,
enum btrace_read_type);
/* Read branch trace data for the thread indicated by BTINFO into DATA.
DATA is cleared before new trace is added.
The branch trace will start with the most recent block and continue
towards older blocks. */
enum btrace_error (*to_read_btrace) (VEC (btrace_block_s) **data,
struct btrace_target_info *btinfo,
enum btrace_read_type type);
/* Stop trace recording. */
void (*to_stop_recording) (void);
@ -1998,8 +2002,9 @@ extern void target_disable_btrace (struct btrace_target_info *btinfo);
extern void target_teardown_btrace (struct btrace_target_info *btinfo);
/* See to_read_btrace in struct target_ops. */
extern VEC (btrace_block_s) *target_read_btrace (struct btrace_target_info *,
enum btrace_read_type);
extern enum btrace_error target_read_btrace (VEC (btrace_block_s) **,
struct btrace_target_info *,
enum btrace_read_type);
/* See to_stop_recording in struct target_ops. */
extern void target_stop_recording (void);