[Perf, Test] (ShaderTranspiler, DirectGLES): answer both pass-gate probes from one SPIR-V parse

MobileGL/MG_Backend/DirectGLES/Managers.cpp

@@ -4909,9 +4909,32 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 // fails to compile and every draw made with it silently renders nothing.
                 // Gated on the module actually declaring the output, so no other stage pays an
                 // optimizer round trip for it.
+                // One parse of the module answers every armed pass gate below. The per-gate
+                // Declares* probes each cost a BuildModule per stage, and on a driver where both
+                // gates are armed (Mali: no GL_OES_viewport_array AND integer multisample
+                // squeezed to 1) the doubled parse made compile-heavy workloads ~10% slower.
+                // Probing the pre-lowering module is sound for both gates: demoting
+                // gl_ViewportIndex neither adds nor removes multisampled image types.
+                // Recomputed here rather than calling GL_Getter's GetAdvertisedMaxSamples():
+                // this is backend code and must not reach into the GL frontend. 4 is that
+                // translation unit's kFrontendMaxSamples, which is the source of truth -
+                // keep the two in step.
+                constexpr Int kFrontendMaxSamples = 4;
+                const Int advertisedMaxSamples =
+                    std::max(g_GLESCapabilities.MaxSamples, kFrontendMaxSamples);
+                const Bool viewportLoweringArmed = !g_GLESCapabilities.SupportsViewportArray;
+                const Bool sampleClampArmed =
+                    g_GLESCapabilities.MaxColorTextureSamples < advertisedMaxSamples ||
+                    g_GLESCapabilities.MaxIntegerSamples < advertisedMaxSamples ||
+                    g_GLESCapabilities.MaxDepthTextureSamples < advertisedMaxSamples;
+                MG_Util::ShaderTranspiler::ShaderCompiler::SpirvGateFeatures spirvGates;
+                if (viewportLoweringArmed || sampleClampArmed) {
+                    spirvGates = MG_Util::ShaderTranspiler::ShaderCompiler::ProbeSpirvGateFeatures(
+                        *effectiveSpirv);
+                }
+
                 Vector<unsigned int> loweredViewportSpirv;
-                if (!g_GLESCapabilities.SupportsViewportArray &&
-                    MG_Util::ShaderTranspiler::ShaderCompiler::DeclaresViewportIndexBuiltin(*effectiveSpirv) &&
+                if (viewportLoweringArmed && spirvGates.WritesViewportIndexOutput &&
                     MG_Util::ShaderTranspiler::ShaderCompiler::LowerViewportIndexForEssl(
                         *effectiveSpirv, loweredViewportSpirv, enableSpirvValidation) &&
                     !loweredViewportSpirv.empty()) {
@@ -4937,28 +4960,15 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 // optimizer round trip for it. DirectVulkan is deliberately not given this: it
                 // allocates the sample count it was asked for, so its modules are already right.
                 Vector<unsigned int> clampedSampleSpirv;
-                {
-                    // Recomputed here rather than calling GL_Getter's GetAdvertisedMaxSamples():
-                    // this is backend code and must not reach into the GL frontend. 4 is that
-                    // translation unit's kFrontendMaxSamples, which is the source of truth -
-                    // keep the two in step.
-                    constexpr Int kFrontendMaxSamples = 4;
-                    const Int advertisedMaxSamples =
-                        std::max(g_GLESCapabilities.MaxSamples, kFrontendMaxSamples);
-                    if ((g_GLESCapabilities.MaxColorTextureSamples < advertisedMaxSamples ||
-                         g_GLESCapabilities.MaxIntegerSamples < advertisedMaxSamples ||
-                         g_GLESCapabilities.MaxDepthTextureSamples < advertisedMaxSamples) &&
-                        MG_Util::ShaderTranspiler::ShaderCompiler::DeclaresMultisampledImage(
-                            *effectiveSpirv) &&
-                        MG_Util::ShaderTranspiler::ShaderCompiler::ClampMultisampleFetchesForEssl(
-                            *effectiveSpirv, clampedSampleSpirv,
-                            g_GLESCapabilities.MaxColorTextureSamples,
-                            g_GLESCapabilities.MaxIntegerSamples,
-                            g_GLESCapabilities.MaxDepthTextureSamples, advertisedMaxSamples,
-                            enableSpirvValidation) &&
-                        !clampedSampleSpirv.empty()) {
-                        effectiveSpirv = &clampedSampleSpirv;
-                    }
+                if (sampleClampArmed && spirvGates.DeclaresMultisampledImage &&
+                    MG_Util::ShaderTranspiler::ShaderCompiler::ClampMultisampleFetchesForEssl(
+                        *effectiveSpirv, clampedSampleSpirv,
+                        g_GLESCapabilities.MaxColorTextureSamples,
+                        g_GLESCapabilities.MaxIntegerSamples,
+                        g_GLESCapabilities.MaxDepthTextureSamples, advertisedMaxSamples,
+                        enableSpirvValidation) &&
+                    !clampedSampleSpirv.empty()) {
+                    effectiveSpirv = &clampedSampleSpirv;
                 }
 
                 // GLSL ES has no ARRAY vertex inputs, and SPIRV-Cross refuses the whole module

MobileGL/MG_Test/ShaderTranspiler/ClampMultisampleFetchTest.cpp

@@ -247,6 +247,26 @@ TEST_F(ClampMultisampleFetchTest, TheProbeAnswersOnlyForAMultisampledImage) {
     EXPECT_FALSE(ShaderCompiler::DeclaresMultisampledImage({}));
 }
 
+// The combined probe answers both gate questions from one parse; it must agree with the
+// per-gate probes on the same modules and stay quiet for an empty stage.
+TEST_F(ClampMultisampleFetchTest, TheCombinedProbeAgreesWithThePerGateOnes) {
+    const Vector<Uint32> integerMs = CompileFragment(kIntegerMultisampleFetch);
+    ASSERT_FALSE(integerMs.empty());
+    const auto msFeatures = ShaderCompiler::ProbeSpirvGateFeatures(integerMs);
+    EXPECT_TRUE(msFeatures.DeclaresMultisampledImage);
+    EXPECT_FALSE(msFeatures.WritesViewportIndexOutput);
+
+    const Vector<Uint32> plain = CompileFragment(kNoMultisampleFetch);
+    ASSERT_FALSE(plain.empty());
+    const auto plainFeatures = ShaderCompiler::ProbeSpirvGateFeatures(plain);
+    EXPECT_FALSE(plainFeatures.DeclaresMultisampledImage);
+    EXPECT_FALSE(plainFeatures.WritesViewportIndexOutput);
+
+    const auto emptyFeatures = ShaderCompiler::ProbeSpirvGateFeatures({});
+    EXPECT_FALSE(emptyFeatures.DeclaresMultisampledImage);
+    EXPECT_FALSE(emptyFeatures.WritesViewportIndexOutput);
+}
+
 // The overwhelming majority of modules. Behind the probe they never reach the pass at all, but the
 // pass has to be inert for them on its own, or a future caller that forgets the gate silently
 // re-serialises every shader in the program.

MobileGL/MG_Util/ShaderTranspiler/ShaderCompiler.cpp

@@ -672,6 +672,28 @@ namespace MobileGL {
                 return ClampMultisampleFetchPass::DeclaresMultisampledImage(binary);
             }
 
+            ShaderCompiler::SpirvGateFeatures ShaderCompiler::ProbeSpirvGateFeatures(
+                const Vector<Uint32>& binary) {
+                SpirvGateFeatures features;
+                if (binary.empty()) {
+                    return features;
+                }
+                std::unique_ptr<spvtools::opt::IRContext> context = spvtools::BuildModule(
+                    SPV_ENV_VULKAN_1_1,
+                    [](spv_message_level_t, const char*, const spv_position_t&, const char*) {},
+                    binary.data(), binary.size());
+                if (!context) {
+                    // Unparseable here means unusable downstream too; let the ordinary transpile
+                    // path produce the error rather than inventing a verdict from it.
+                    return features;
+                }
+                features.WritesViewportIndexOutput =
+                    LowerViewportIndexPass::DeclaresViewportIndexBuiltin(context.get());
+                features.DeclaresMultisampledImage =
+                    ClampMultisampleFetchPass::DeclaresMultisampledImage(context.get());
+                return features;
+            }
+
             bool ShaderCompiler::SplitArrayVertexInputsForEssl(const Vector<Uint32>& inputBinary,
                                                                Vector<uint32_t>& outputBinary,
                                                                const bool enableSpirvValidation) {

MobileGL/MG_Util/ShaderTranspiler/ShaderCompiler.h

@@ -65,6 +65,16 @@ namespace MobileGL {
                 // above has anything to do. The gate that keeps every other stage off an
                 // optimizer round trip it does not need.
                 static bool DeclaresMultisampledImage(const Vector<Uint32>& binary);
+                // Both gate questions above answered from ONE parse. Every armed gate costs a
+                // BuildModule per shader stage, and on a driver where both are armed (Mali: no
+                // GL_OES_viewport_array AND integer multisample squeezed to 1) the separate
+                // probes made compile-heavy workloads measurably slower - ReservedNames-class
+                // CTS cases paid ~10%. Callers with more than one armed gate use this instead.
+                struct SpirvGateFeatures {
+                    Bool WritesViewportIndexOutput = false;
+                    Bool DeclaresMultisampledImage = false;
+                };
+                static SpirvGateFeatures ProbeSpirvGateFeatures(const Vector<Uint32>& binary);
                 // Replaces an ARRAY vertex input with one input per element at consecutive
                 // locations, seeding a Private copy of the array so indexed reads still work.
                 // GLSL ES has no array vertex inputs and SPIRV-Cross refuses the whole module

MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/ClampMultisampleFetchPass.cpp

@@ -198,6 +198,10 @@ namespace MobileGL {
                     // path produce the error rather than inventing a verdict from it.
                     return false;
                 }
+                return DeclaresMultisampledImage(context.get());
+            }
+
+            bool ClampMultisampleFetchPass::DeclaresMultisampledImage(IRContext* context) {
                 for (const Instruction& type : context->module()->types_values()) {
                     if (IsMultisampledImageType(&type)) {
                         return true;

MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/ClampMultisampleFetchPass.h

@@ -74,6 +74,10 @@ namespace MobileGL {
                 // that read a multisample texture directly.
                 static bool DeclaresMultisampledImage(const Vector<Uint32>& binary);
 
+                // Same question answered from an already-built module, so one parse can feed
+                // several gates (ShaderCompiler::ProbeSpirvGateFeatures).
+                static bool DeclaresMultisampledImage(spvtools::opt::IRContext* context);
+
                 static spvtools::Optimizer::PassToken CreateClampMultisampleFetchPass(
                     Int32 maxColorSamples, Int32 maxIntegerSamples, Int32 maxDepthSamples,
                     Int32 advertisedMaxSamples);

MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerViewportIndexPass.cpp

@@ -138,9 +138,13 @@ namespace MobileGL {
                     // path produce the error rather than inventing a verdict from it.
                     return false;
                 }
+                return DeclaresViewportIndexBuiltin(context.get());
+            }
+
+            bool LowerViewportIndexPass::DeclaresViewportIndexBuiltin(IRContext* context) {
                 for (const Instruction& annotation : context->annotations()) {
                     if (IsViewportIndexBuiltinDecoration(annotation) &&
-                        GetDecoratedViewportIndexOutput(context.get(), annotation) != nullptr) {
+                        GetDecoratedViewportIndexOutput(context, annotation) != nullptr) {
                         return true;
                     }
                 }

MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/LowerViewportIndexPass.h

@@ -44,6 +44,10 @@ namespace MobileGL {
                 // but the handful that route viewports from the shader.
                 static bool DeclaresViewportIndexBuiltin(const Vector<Uint32>& binary);
 
+                // Same question answered from an already-built module, so one parse can feed
+                // several gates (ShaderCompiler::ProbeSpirvGateFeatures).
+                static bool DeclaresViewportIndexBuiltin(spvtools::opt::IRContext* context);
+
                 static spvtools::Optimizer::PassToken CreateLowerViewportIndexPass();
             };
         } // namespace ShaderTranspiler