Currently the Gecko Profiler defines a moderate amount of stuff when
MOZ_GECKO_PROFILER is undefined. It also #includes various headers, including
JS ones. This is making it difficult to separate Gecko's media stack for
inclusion in Servo.
This patch greatly simplifies how things are exposed. The starting point is:
- GeckoProfiler.h can be #included unconditionally;
- everything else from the profiler must be guarded by MOZ_GECKO_PROFILER.
In practice this introduces way too many #ifdefs, so the patch loosens it by
adding no-op macros for a number of the most common operations.
The net result is that #ifdefs and macros are used a bit more, but almost
nothing is exposed in non-MOZ_GECKO_PROFILER builds (including
ProfilerMarkerPayload.h and GeckoProfiler.h), and understanding what is exposed
is much simpler than before.
Note also that in BHR, ThreadStackHelper is now entirely absent in
non-MOZ_GECKO_PROFILER builds.
This requires:
- Moving the constructors of ProfilerMarkerPayload and its subclasses into the
.h file so they are visible even when ProfilerMarkerPayload.cpp isn't
compiled.
- Similarly, using a macro to make StreamPayload() a crashing no-op when the
profiler isn't enabled. (It is never called in that case.)
This patch reduces the differences between builds where the profiler is enabled
and those where the profiler is disabled. It does this by removing numerous
MOZ_GECKO_PROFILER checks.
These changes have the following consequences.
- Various functions and classes are now defined in all builds, and so can be
used unconditionally: profiler_add_marker(), profiler_set_js_context(),
profiler_clear_js_context(), profiler_get_pseudo_stack(), AutoProfilerLabel.
(They are effectively no-ops in non-profiler builds, of course.)
- The no-op versions of PROFILER_* are now gone. The remaining versions are
almost no-ops when the profiler isn't built.
Once the |aPayload| argument to profile_add_marker() became a UniquePtr the
default value of nullptr caused compilation difficulties that could only be
fixed by #including ProfilerMarkerPayload.h into lots of additional places
(because the UniquePtr<T> instantiation required the T to be fully defined). To
get around this I just split profile_add_marker() into two functions, one with
1 argument and one with 2 arguments.
The patch also removes the definition of PROFILER_MARKER_PAYLOAD in the case
where MOZ_GECKO_PROFILER isn't defined. A comment explains why.
When we just had CycleCollectedJSContext (and no CycleCollectedJSRuntime) a
weird thing happened at shutdown:
1. We would call JS_DestroyContext from ~CycleCollectedJSContext. By that time,
the ~XPCJSContext destructor had already finished.
2. Destroying the context runs a final GC. That GC would call back into various
GC callbacks, such as TraceBlackJS and TraceGrayJS.
3. These callbacks would do a virtual method call:
http://searchfox.org/mozilla-central/rev/876c7dd30586f9c6f9c99ef7444f2d73c7acfe7c/xpcom/base/CycleCollectedJSRuntime.cpp#791
4. Normally this method call would call into
XPCContext::TraceNativeBlackRoots. However, C++ changes the vtable for an
object during destruction. So we would only call CycleCollectedJSContext's
version of TraceNativeBlackRoots, which is empty. So we never traced anything.
When I moved this code into the runtime, we actually do call into
XPCJSRuntime::TraceNativeBlackRoots at that time. So the behavior changed, and
that was causing crashes once I nulled out the TLS as you asked. So I removed
these callbacks for the last GC.
MozReview-Commit-ID: 3do13bjpwQj
This patch keeps a list of all the cooperatively scheduled contexts that are
linked to a runtime. In places where we need to iterate over all contexts (for
GC, specifically), it iterates over the list.
MozReview-Commit-ID: 3pKJX78f2l0
To run JS in separate cooperative threads, we need to split up per-thread state
from per-runtime state. This patch does that for XPConnect.
MozReview-Commit-ID: 407SlJ7nR6v
This change avoids lots of false positives for Coverity's CHECKED_RETURN
warning, caused by NS_WARN_IF's current use in both statement-style and
expression-style.
In the case where the code within the NS_WARN_IF has side-effects, I made the
following change.
> NS_WARN_IF(NS_FAILED(FunctionWithSideEffects()));
> -->
> Unused << NS_WARN_IF(NS_FAILED(FunctionWithSideEffects()));
In the case where the code within the NS_WARN_IF lacks side-effects, I made the
following change.
> NS_WARN_IF(!condWithoutSideEffects);
> -->
> NS_WARNING_ASSERTION(condWithoutSideEffects, "msg");
This has two improvements.
- The condition is not evaluated in non-debug builds.
- The sense of the condition is inverted to the familiar "this condition should
be true" sense used in assertions.
A common variation on the side-effect-free case is the following.
> nsresult rv = Fn();
> NS_WARN_IF_(NS_FAILED(rv));
> -->
> DebugOnly<nsresult rv> = Fn();
> NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Fn failed");
