Bug 1646266 - CorePS buffer access - r=gregtatum

The upcoming profiler-specific add-marker function will need to know which `ProfileChunkedBuffer` to serialize to, `profiler_get_core_buffer()` give access to the profiler's buffer, and `CachedCoreBuffer()` keeps it stored in a function-static object.

Differential Revision: https://phabricator.services.mozilla.com/D87256

mozglue/baseprofiler/core/platform.cpp

@@ -419,7 +419,7 @@ class CorePS {
   PS_GET_LOCKLESS(int, MainThreadId)
 
   // No PSLockRef is needed for this field because it's immutable.
-  PS_GET_LOCKLESS(TimeStamp, ProcessStartTime)
+  PS_GET_LOCKLESS(const TimeStamp&, ProcessStartTime)
 
   // No PSLockRef is needed for this field because it's thread-safe.
   PS_GET_LOCKLESS(ProfileChunkedBuffer&, CoreBuffer)
@@ -568,6 +568,11 @@ class CorePS {
 
 CorePS* CorePS::sInstance = nullptr;
 
+ProfileChunkedBuffer& profiler_get_core_buffer() {
+  MOZ_ASSERT(CorePS::Exists());
+  return CorePS::CoreBuffer();
+}
+
 class SamplerThread;
 
 static SamplerThread* NewSamplerThread(PSLockRef aLock, uint32_t aGeneration,

mozglue/baseprofiler/public/BaseProfilerMarkersDetail.h

@@ -22,6 +22,23 @@
 
 #  include <limits>
 
+namespace mozilla::baseprofiler {
+// Implemented in platform.cpp
+MFBT_API ProfileChunkedBuffer& profiler_get_core_buffer();
+}  // namespace mozilla::baseprofiler
+
+namespace mozilla::base_profiler_markers_detail {
+
+// Get the core buffer from the profiler, and cache it in a
+// non-templated-function static reference.
+inline ProfileChunkedBuffer& CachedBaseCoreBuffer() {
+  static ProfileChunkedBuffer& coreBuffer =
+      baseprofiler::profiler_get_core_buffer();
+  return coreBuffer;
+}
+
+}  // namespace mozilla::base_profiler_markers_detail
+
 namespace mozilla {
 
 // ----------------------------------------------------------------------------

tools/profiler/core/platform.cpp

@@ -695,6 +695,11 @@ class CorePS {
 
 CorePS* CorePS::sInstance = nullptr;
 
+ProfileChunkedBuffer& profiler_get_core_buffer() {
+  MOZ_ASSERT(CorePS::Exists());
+  return CorePS::CoreBuffer();
+}
+
 class SamplerThread;
 
 static SamplerThread* NewSamplerThread(PSLockRef aLock, uint32_t aGeneration,

tools/profiler/public/ProfilerMarkersDetail.h

@@ -23,6 +23,20 @@
 // Header that specializes the (de)serializers for xpcom types.
 #  include "mozilla/ProfileBufferEntrySerializationGeckoExtensions.h"
 
+// Implemented in platform.cpp
+mozilla::ProfileChunkedBuffer& profiler_get_core_buffer();
+
+namespace profiler_markers_detail {
+
+// Get the core buffer from the profiler, and cache it in a
+// non-templated-function static reference.
+inline mozilla::ProfileChunkedBuffer& CachedCoreBuffer() {
+  static mozilla::ProfileChunkedBuffer& coreBuffer = profiler_get_core_buffer();
+  return coreBuffer;
+}
+
+}  // namespace profiler_markers_detail
+
 #endif  // MOZ_GECKO_PROFILER
 
 #endif  // ProfilerMarkersDetail_h