This was causing a crash on nightly. The browser would try to collect only a
native stack, and then attempt to dereference the null pointer for the
pseudostack. I think this didn't happen on infra as it only occurs when the user
has hung a sufficient number of times.
MozReview-Commit-ID: 6RSW2llKBjT
This patch uses the profiler_suspend_sample_thread method which was added in
part 1.
With this patch, we no longer manually run code to pause the target thread,
instead using the profiler's provided code to do so. In addition, we no longer
manually walk the stack to collect native stack frames, instead relying on the
profiler's cross-platform stack walking logic.
This helps remove some of the code from ThreadStackHelper which was redundant
with the profiler. Much of the pseudostack code in ThreadStackHelper is also
redundant, and should hopefully be eliminated in a follow-up.
MozReview-Commit-ID: 4RjLHt6inH9
These annotations aren't doing anything useful. The important thing with
the PseudoStack is that, during pushes, the stack pointer incrementing happens
after the new entry is written, and this is ensured by the stack pointer being
Atomic.
The patch also improves the comments on PseudoStack.
This includes renaming its fields to match SpiderMonkey naming conventions
instead of Gecko naming conventions.
This patch is just about moving the code. The next patch will change
SpiderMonkey to actually use PseudoStack directly.
ProfileEntry has |string|, which can be static or dynamic, and |dynamicString|.
If |string| is dynamic, the FRAME_LABEL_COPY flag must be set, and it will be
copied into profiler output.
But there is only one place that uses dynamic |string| values, in SpiderMonkey.
And that place doesn't use |dynamicString|. So this patch changes that place to
use an empty |string| and put the old dynamic |string| value in
|dynamicString|. This in turn removes the need for FRAME_LABEL_COPY.
One minor wrinkle is that when |dynamicString| is used the old code put a space
between |string| and |dynamicString|. The new code omits the space if |string|
is empty.
The patch also renames ProfileEntry::string as ProfileEntry::label_, which
better matches how it's used, and ProfileEntry::dynamicString as
ProfileEntry::dynamicString_ so the getter can be renamed dynamicString().
This patch uses the profiler_suspend_sample_thread method which was added in
part 1.
With this patch, we no longer manually run code to pause the target thread,
instead using the profiler's provided code to do so. In addition, we no longer
manually walk the stack to collect native stack frames, instead relying on the
profiler's cross-platform stack walking logic.
This helps remove some of the code from ThreadStackHelper which was redundant
with the profiler. Much of the pseudostack code in ThreadStackHelper is also
redundant, and should hopefully be eliminated in a follow-up.
MozReview-Commit-ID: 4RjLHt6inH9
This possibly incurs an extra function call (depends on exactly how much inling
the compiler does). But it helps enormously with subsequent refactorings,
because PseudoStack (and related types) don't need to be visible in
GeckoProfiler.h, which is exported outside the profiler.
This commit contains a few things:
* Update our copy of google-breakpad to upstream c53ed143108948eb7e2d7ee77dc8c0d92050ce7c
* Get rid of all but one local patch, fold a few related local patches into one
* Misc build fixup to sync with upstream--adding a few new moz.build files,
source files
* The final bits of unhooking Breakpad from the profiler:
** Revert to only building toolkit/crashreporter if MOZ_CRASHREPORTER.
** Stop building bits of Breakpad that we only needed for the profiler.
** Remove a few bits of profiler code that were used to interface with Breakpad.
** Remove toolkit/crashreporter/breakpad-logging, which was only used to
suppress Breakpad logging for the in-process stackwalker.
* Upstream removed their Android-compat sys/ucontext.h because the Android NDK
added it, but the bionic we're using for Gonk builds is too old, so add a
copy of the previous version of those files to
toolkit/crashreporter/gonk-include to keep Gonk building.
* Consolidate moz.build files under toolkit/crashreporter/google-breakpad/client/linux
The breakpad dependency in ThreadStackHelper is preventing us from
upgrading our in-tree copy to a newer version (bug 1069556). This patch
gets rid of that dependency. This makes native stack frames not work
for BHR, but because of the ftp.m.o decommissioning, native
symbolication was already broken and naive stack frames already don't
work, so we don't really lose anything from this patch.
Eventually we want to make ThreadStackHelper use other means of
unwinding, such as LUL for Linux
I added | #if 0 | around the code to fill the thread context, but left
the code in because I think we'll evenually want to reuse some of that
code.
The bulk of this commit was generated by running:
run-clang-tidy.py \
-checks='-*,llvm-namespace-comment' \
-header-filter=^/.../mozilla-central/.* \
-fix
When we're inside the hang monitor's signal handler, we must not read any string labels. Doing so may result in on-demand decompression kicking in on Android, which may result in a deadlock.
