Bug 1622327. Add support for adding profiling event markers to WebRender. r=kvark

I plan on using this to add texture cache reallocation events.

Differential Revision: https://phabricator.services.mozilla.com/D66792

--HG--
extra : moz-landing-system : lando

gfx/layers/wr/WebRenderBridgeParent.cpp

@@ -72,6 +72,14 @@ void gecko_profiler_end_marker(const char* name) {
 #endif
 }
 
+void gecko_profiler_event_marker(const char* name) {
+#ifdef MOZ_GECKO_PROFILER
+  profiler_tracing_marker("WebRender", name,
+                          JS::ProfilingCategoryPair::GRAPHICS,
+                          TRACING_EVENT);
+#endif
+}
+
 void gecko_profiler_add_text_marker(const char* name, const char* text_bytes,
                                     size_t text_len, uint64_t microseconds) {
 #ifdef MOZ_GECKO_PROFILER

gfx/webrender_bindings/src/bindings.rs

@@ -819,6 +819,7 @@ pub unsafe extern "C" fn wr_renderer_flush_pipeline_info(renderer: &mut Renderer
 extern "C" {
     pub fn gecko_profiler_start_marker(name: *const c_char);
     pub fn gecko_profiler_end_marker(name: *const c_char);
+    pub fn gecko_profiler_event_marker(name: *const c_char);
     pub fn gecko_profiler_add_text_marker(
         name: *const c_char,
         text_bytes: *const c_char,
@@ -845,6 +846,12 @@ impl ProfilerHooks for GeckoProfilerHooks {
         }
     }
 
+    fn event_marker(&self, label: &CStr) {
+        unsafe {
+            gecko_profiler_event_marker(label.as_ptr());
+        }
+    }
+
     fn add_text_marker(&self, label: &CStr, text: &str, duration: Duration) {
         unsafe {
             // NB: This can be as_micros() once we require Rust 1.33.

gfx/webrender_bindings/webrender_ffi.h

@@ -33,6 +33,7 @@ void gecko_profiler_unregister_thread();
 
 void gecko_profiler_start_marker(const char* name);
 void gecko_profiler_end_marker(const char* name);
+void gecko_profiler_event_marker(const char* name);
 void gecko_profiler_add_text_marker(const char* name, const char* text_ptr,
                                     size_t text_len, uint64_t microseconds);
 bool gecko_profiler_thread_is_being_profiled();

gfx/wr/webrender/src/profiler.rs

@@ -82,6 +82,10 @@ pub trait ProfilerHooks : Send + Sync {
     /// be a C string (null terminated).
     fn end_marker(&self, label: &CStr);
 
+    /// Called to mark an event happening. The label must
+    /// be a C string (null terminated).
+    fn event_marker(&self, label: &CStr);
+
     /// Called with a duration to indicate a text marker that just ended. Text
     /// markers allow different types of entries to be recorded on the same row
     /// in the timeline, by adding labels to the entry.
@@ -123,6 +127,15 @@ pub fn add_text_marker(label: &CStr, text: &str, duration: Duration) {
     }
 }
 
+/// Records a marker of the given duration that just ended.
+pub fn add_event_marker(label: &CStr) {
+    unsafe {
+        if let Some(ref hooks) = PROFILER_HOOKS {
+            hooks.event_marker(label);
+        }
+    }
+}
+
 /// Returns true if the current thread is being profiled.
 pub fn thread_is_being_profiled() -> bool {
     unsafe {