Add LINK_STATUS to completion query

This stores program LINK_STATUS to the GL_QUERY_RESULT of
GL_PROGRAM_COMPLETION_QUERY_CHROMIUM. WebGL useProgram checks
the status before using it. By caching this status, useProgram
no longer stalls on the round-trip to the GPU thread.

Bug: 962337
Change-Id: Ifcc15044b1e6e6813e0599d90a76556b2401396a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1607573
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661134}

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_completion_query.txt

@@ -28,8 +28,13 @@ Overview
         glEndQueryEXT(PROGRAM_COMPLETION_QUERY_CHROMIUM);
         GLuint available = 0u;
         glGetQueryObjectuivEXT(query, GL_QUERY_RESULT_AVAILABLE, &available);
+        if (available)
+        {
+          GLuint result = 0u;
+          glGetQueryObjectuivEXT(query, GL_QUERY_RESULT, &result);
+        }
     If 'available' returns true, that's equivalent to COMPLETION_STATUS_KHR
-    returning true.
+    returning true. Then LINK_STATUS can be obtained from 'result'.
 
 New Procedures and Functions
 

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

@@ -2156,8 +2156,13 @@ error::Error GLES2DecoderPassthroughImpl::ProcessQueries(bool did_finish) {
           } else {
             program_completion_query_deferred = true;
           }
+          result = 0;
+        } else {
+          GLint link_status = 0;
+          api()->glGetProgramivFn(query.program_service_id, GL_LINK_STATUS,
+                                  &link_status);
+          result = link_status;
         }
-        result = 0;
         break;
 
       default:

third_party/blink/renderer/modules/webgl/webgl_program.cc

@@ -162,8 +162,16 @@ void WebGLProgram::CacheInfoIfNeeded(WebGLRenderingContextBase* context) {
   if (!object_)
     return;
   gpu::gles2::GLES2Interface* gl = context->ContextGL();
-  link_status_ = 0;
-  gl->GetProgramiv(object_, GL_LINK_STATUS, &link_status_);
+  GLint link_status = 0;
+  gl->GetProgramiv(object_, GL_LINK_STATUS, &link_status);
+  setLinkStatus(link_status);
+}
+
+void WebGLProgram::setLinkStatus(bool link_status) {
+  if (info_valid_)
+    return;
+
+  link_status_ = link_status;
   if (link_status_ == GL_TRUE) {
     required_transform_feedback_buffer_count_ =
         required_transform_feedback_buffer_count_after_next_link_;

third_party/blink/renderer/modules/webgl/webgl_program.h

@@ -42,6 +42,7 @@ class WebGLProgram final : public WebGLSharedPlatform3DObject {
   static WebGLProgram* Create(WebGLRenderingContextBase*);
 
   bool LinkStatus(WebGLRenderingContextBase*);
+  void setLinkStatus(bool link_status);
 
   bool CompletionStatus(WebGLRenderingContextBase*);
 

third_party/blink/renderer/modules/webgl/webgl_rendering_context_base.cc

@@ -8210,6 +8210,11 @@ bool WebGLRenderingContextBase::checkProgramCompletionQueryAvailable(
     GLuint available;
     ContextGL()->GetQueryObjectuivEXT(id, GL_QUERY_RESULT_AVAILABLE,
                                       &available);
+    if (available) {
+      GLuint result = 0u;
+      ContextGL()->GetQueryObjectuivEXT(id, GL_QUERY_RESULT, &result);
+      program->setLinkStatus(result);
+    }
     *completed = (available == GL_TRUE);
     return true;
   }