Only update symbols on current thread when breaking or stepping in GDB.
R=ppi@chromium.org
Review URL: https://codereview.chromium.org/1253573008 .
Cr-Mirrored-From: https://github.com/domokit/mojo
Cr-Mirrored-Commit: c02a28868825edfa57ab77947b8cb15e741c5598
diff --git a/README.md b/README.md
index 9e063f1..d9dee44 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,7 @@
`about://tracing`.
#### GDB
-It is possible to inspect a Mojo Shell process using GDB. The `debugger` script
+It is possible to inspect a Mojo Shell process using GDB. The `mojo_debug` script
can be used to launch GDB and attach it to a running shell process (android
only):
@@ -47,9 +47,26 @@
mojo_debug gdb attach
```
+Once started, GDB will first stop the Mojo Shell execution, then load symbols
+from loaded Mojo applications. Please note that this initial step can take some
+time (up to several minutes in the worst case).
+
+After each execution pause, GDB will update the set of loaded symbols based on
+the selected thread only. If you need symbols for all threads, use the
+`update-symbols` GDB command:
+```sh
+(gdb) update-symbols
+```
+
+If you only want to update symbols for the current selected thread (for example,
+after changing threads), use the `current` option:
+```sh
+(gdb) update-symbols current
+```
+
#### Android crash stacks
When Mojo shell crashes on Android ("Unfortunately, Mojo shell has stopped.")
-due to a crash in native code, `debugger` can be used to find and symbolize the
+due to a crash in native code, `mojo_debug` can be used to find and symbolize the
stack trace present in the device log:
```sh
diff --git a/android_gdb/session.py b/android_gdb/session.py
index bc05c29..b16fe55 100644
--- a/android_gdb/session.py
+++ b/android_gdb/session.py
@@ -190,13 +190,33 @@
return True
return False
- def _update_symbols(self):
+ def _map_symbols_on_current_thread(self, mapped_files):
+ """Updates the symbols for the current thread using files from mapped_files.
+ """
+ frame = gdb.newest_frame()
+ while frame and frame.is_valid():
+ if frame.name() is None:
+ m = self._find_mapping_for_address(mapped_files, frame.pc())
+ if m is not None and self._try_to_map(m):
+ # Force gdb to recompute its frames.
+ _gdb_execute("info threads")
+ frame = gdb.newest_frame()
+ assert frame.is_valid()
+ if (frame.older() is not None and
+ frame.older().is_valid() and
+ frame.older().pc() != frame.pc()):
+ frame = frame.older()
+ else:
+ frame = None
+
+ def update_symbols(self, current_thread_only):
"""Updates the mapping between symbols as seen from GDB and local library
- files."""
+ files.
+
+ If current_thread_only is True, only update symbols for the current thread.
+ """
logging.info("Updating symbols")
mapped_files = _get_mapped_files()
- _gdb_execute("info threads")
- nb_threads = len(_gdb_execute("info threads").split("\n")) - 2
# Map all symbols from native libraries packages with the APK.
for file_mappings in mapped_files:
filename = file_mappings[0].filename
@@ -206,26 +226,20 @@
not filename.endswith('.dex')):
logging.info('Pre-mapping: %s' % file_mappings[0].filename)
self._try_to_map(file_mappings)
- for i in xrange(nb_threads):
- try:
- _gdb_execute("thread %d" % (i + 1))
- frame = gdb.newest_frame()
- while frame and frame.is_valid():
- if frame.name() is None:
- m = self._find_mapping_for_address(mapped_files, frame.pc())
- if m is not None and self._try_to_map(m):
- # Force gdb to recompute its frames.
- _gdb_execute("info threads")
- frame = gdb.newest_frame()
- assert frame.is_valid()
- if (frame.older() is not None and
- frame.older().is_valid() and
- frame.older().pc() != frame.pc()):
- frame = frame.older()
- else:
- frame = None
- except gdb.error:
- traceback.print_exc()
+
+ if current_thread_only:
+ self._map_symbols_on_current_thread(mapped_files)
+ else:
+ logging.info('Updating all threads\' symbols')
+ current_thread = gdb.selected_thread()
+ nb_threads = len(_gdb_execute("info threads").split("\n")) - 2
+ for i in xrange(nb_threads):
+ try:
+ _gdb_execute("thread %d" % (i + 1))
+ self._map_symbols_on_current_thread(mapped_files)
+ except gdb.error:
+ traceback.print_exc()
+ current_thread.switch()
def _get_device_application_pid(self, application):
"""Gets the PID of an application running on a device."""
@@ -266,8 +280,38 @@
_gdb_execute('target remote localhost:9999')
- self._update_symbols()
+ self.update_symbols(current_thread_only=False)
def on_stop(_):
- self._update_symbols()
+ self.update_symbols(current_thread_only=True)
gdb.events.stop.connect(on_stop)
gdb.events.exited.connect(self.stop)
+
+ # Register the update-symbols command.
+ UpdateSymbols(self)
+
+class UpdateSymbols(gdb.Command):
+ """Command to update symbols loaded into GDB.
+
+ GDB usage: update-symbols [all|current]
+ """
+ _UPDATE_COMMAND = "update-symbols"
+
+ def __init__(self, session):
+ super(UpdateSymbols, self).__init__(self._UPDATE_COMMAND, gdb.COMMAND_STACK)
+ self._session = session
+
+ def invoke(self, arg, _unused_from_tty):
+ if arg == 'current':
+ self._session.update_symbols(current_thread_only=True)
+ else:
+ self._session.update_symbols(current_thread_only=False)
+
+ def complete(self, text, _unused_word):
+ if text == self._UPDATE_COMMAND:
+ return ('all', 'current')
+ elif text in self._UPDATE_COMMAND + ' all':
+ return ['all']
+ elif text in self._UPDATE_COMMAND + ' current':
+ return ['current']
+ else:
+ return []
