Vulkan: Warm up glslang on startup

As soon as glslang is initialized (which is done when EGL is
initialized), try to compile a simple shader.  This will warm up
glslang's internals to avoid hitches on first shader compilation when a
WebGL application starts.

Potential future optimization is to use a worker thread to do this.

Bug: chromium:1091440
Change-Id: I6ac22e982d748af52a6e8b61239889425edc2edb
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2280401
Reviewed-by: Jamie Madill <[email protected]>
Commit-Queue: Shahbaz Youssefi <[email protected]>

Author: ShabbyX

src/libANGLE/renderer/glslang_wrapper_utils.cpp

@@ -36,6 +36,7 @@ ANGLE_REENABLE_EXTRA_SEMI_WARNING
 #include "common/utilities.h"
 #include "libANGLE/Caps.h"
 #include "libANGLE/ProgramLinkedResources.h"
+#include "libANGLE/trace.h"
 
 #define ANGLE_GLSLANG_CHECK(CALLBACK, TEST, ERR) \
     do                                           \
@@ -99,6 +100,29 @@ void GetBuiltInResourcesFromCaps(const gl::Caps &caps, TBuiltInResource *outBuil
     outBuiltInResources->maxClipDistances                 = caps.maxClipDistances;
 }
 
+// Run at startup to warm up glslang's internals to avoid hitches on first shader compile.
+void GlslangWarmup()
+{
+    ANGLE_TRACE_EVENT0("gpu.angle,startup", "GlslangWarmup");
+
+    EShMessages messages = static_cast<EShMessages>(EShMsgSpvRules | EShMsgVulkanRules);
+    // EShMessages messages = EShMsgDefault;
+
+    TBuiltInResource builtInResources(glslang::DefaultTBuiltInResource);
+    glslang::TShader dummyShader(EShLangVertex);
+
+    const char *kShaderString = R"(#version 450 core
+        void main(){}
+    )";
+    const int kShaderLength   = static_cast<int>(strlen(kShaderString));
+
+    dummyShader.setStringsWithLengths(&kShaderString, &kShaderLength, 1);
+    dummyShader.setEntryPoint("main");
+
+    bool result = dummyShader.parse(&builtInResources, 450, ECoreProfile, false, false, messages);
+    ASSERT(result);
+}
+
 // Test if there are non-zero indices in the uniform name, returning false in that case.  This
 // happens for multi-dimensional arrays, where a uniform is created for every possible index of the
 // array (except for the innermost dimension).  When assigning decorations (set/binding/etc), only
@@ -1704,6 +1728,7 @@ void GlslangInitialize()
 {
     int result = ShInitialize();
     ASSERT(result != 0);
+    GlslangWarmup();
 }
 
 void GlslangRelease()
@@ -1937,6 +1962,8 @@ angle::Result GlslangGetShaderSpirvCode(const GlslangErrorCallback &callback,
             continue;
         }
 
+        ANGLE_TRACE_EVENT0("gpu.angle", "GlslangGetShaderSpirvCode TShader::parse");
+
         const char *shaderString = shaderSources[shaderType].c_str();
         int shaderLength         = static_cast<int>(shaderSources[shaderType].size());
 
@@ -1976,4 +2003,5 @@ angle::Result GlslangGetShaderSpirvCode(const GlslangErrorCallback &callback,
 
     return angle::Result::Continue;
 }
+
 }  // namespace rx

src/libANGLE/renderer/vulkan/ProgramVk.cpp

@@ -286,6 +286,8 @@ std::unique_ptr<LinkEvent> ProgramVk::link(const gl::Context *context,
                                            const gl::ProgramLinkedResources &resources,
                                            gl::InfoLog &infoLog)
 {
+    ANGLE_TRACE_EVENT0("gpu.angle", "ProgramVk::link");
+
     ContextVk *contextVk = vk::GetImpl(context);
     // Link resources before calling GetShaderSource to make sure they are ready for the set/binding
     // assignment done in that function.