[Impeller] Compute shader support (flutter#35750)

ci/licenses_golden/licenses_flutter

@@ -768,6 +768,10 @@ FILE: ../../../flutter/impeller/renderer/backend/metal/blit_pass_mtl.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/blit_pass_mtl.mm
 FILE: ../../../flutter/impeller/renderer/backend/metal/command_buffer_mtl.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/command_buffer_mtl.mm
+FILE: ../../../flutter/impeller/renderer/backend/metal/compute_pass_mtl.h
+FILE: ../../../flutter/impeller/renderer/backend/metal/compute_pass_mtl.mm
+FILE: ../../../flutter/impeller/renderer/backend/metal/compute_pipeline_mtl.h
+FILE: ../../../flutter/impeller/renderer/backend/metal/compute_pipeline_mtl.mm
 FILE: ../../../flutter/impeller/renderer/backend/metal/context_mtl.h
 FILE: ../../../flutter/impeller/renderer/backend/metal/context_mtl.mm
 FILE: ../../../flutter/impeller/renderer/backend/metal/device_buffer_mtl.h
@@ -849,6 +853,14 @@ FILE: ../../../flutter/impeller/renderer/command.cc
 FILE: ../../../flutter/impeller/renderer/command.h
 FILE: ../../../flutter/impeller/renderer/command_buffer.cc
 FILE: ../../../flutter/impeller/renderer/command_buffer.h
+FILE: ../../../flutter/impeller/renderer/compute_command.cc
+FILE: ../../../flutter/impeller/renderer/compute_command.h
+FILE: ../../../flutter/impeller/renderer/compute_pass.cc
+FILE: ../../../flutter/impeller/renderer/compute_pass.h
+FILE: ../../../flutter/impeller/renderer/compute_pipeline_builder.cc
+FILE: ../../../flutter/impeller/renderer/compute_pipeline_builder.h
+FILE: ../../../flutter/impeller/renderer/compute_pipeline_descriptor.cc
+FILE: ../../../flutter/impeller/renderer/compute_pipeline_descriptor.h
 FILE: ../../../flutter/impeller/renderer/context.cc
 FILE: ../../../flutter/impeller/renderer/context.h
 FILE: ../../../flutter/impeller/renderer/descriptor_set_layout.h

impeller/blobcat/blob.fbs

@@ -7,6 +7,7 @@ namespace impeller.fb;
 enum Stage:byte {
   kVertex,
   kFragment,
+  kCompute,
 }
 
 table Blob {

impeller/blobcat/blob_library.cc

@@ -18,6 +18,8 @@ constexpr BlobShaderType ToShaderType(fb::Stage stage) {
       return BlobShaderType::kVertex;
     case fb::Stage::kFragment:
       return BlobShaderType::kFragment;
+    case fb::Stage::kCompute:
+      return BlobShaderType::kCompute;
   }
   FML_UNREACHABLE();
 }

impeller/blobcat/blob_types.h

@@ -9,6 +9,7 @@ namespace impeller {
 enum class BlobShaderType {
   kVertex,
   kFragment,
+  kCompute,
 };
 
 }  // namespace impeller

impeller/blobcat/blob_writer.cc

@@ -22,6 +22,8 @@ std::optional<BlobShaderType> InferShaderTypefromFileExtension(
     return BlobShaderType::kVertex;
   } else if (path == ".frag") {
     return BlobShaderType::kFragment;
+  } else if (path == ".comp") {
+    return BlobShaderType::kCompute;
   }
   return std::nullopt;
 }
@@ -88,6 +90,8 @@ constexpr fb::Stage ToStage(BlobShaderType type) {
       return fb::Stage::kVertex;
     case BlobShaderType::kFragment:
       return fb::Stage::kFragment;
+    case BlobShaderType::kCompute:
+      return fb::Stage::kCompute;
   }
   FML_UNREACHABLE();
 }

impeller/compiler/code_gen_template.h

@@ -20,6 +20,8 @@ constexpr std::string_view kReflectionHeaderTemplate =
 
 #include "impeller/renderer/command.h"                    {# // nogncheck #}
 
+#include "impeller/renderer/compute_command.h"            {# // nogncheck #}
+
 #include "impeller/renderer/descriptor_set_layout.h"      {# // nogncheck #}
 
 #include "impeller/renderer/sampler.h"                    {# // nogncheck #}

impeller/compiler/reflector.cc

@@ -84,6 +84,21 @@ static std::string ExecutionModelToString(spv::ExecutionModel model) {
   }
 }
 
+static std::string ExecutionModelToCommandTypeName(
+    spv::ExecutionModel execution_model) {
+  switch (execution_model) {
+    case spv::ExecutionModel::ExecutionModelVertex:
+    case spv::ExecutionModel::ExecutionModelFragment:
+    case spv::ExecutionModel::ExecutionModelTessellationControl:
+    case spv::ExecutionModel::ExecutionModelTessellationEvaluation:
+      return "Command&";
+    case spv::ExecutionModel::ExecutionModelGLCompute:
+      return "ComputeCommand&";
+    default:
+      return "unsupported";
+  }
+}
+
 static std::string StringToShaderStage(std::string str) {
   if (str == "vertex") {
     return "ShaderStage::kVertex";
@@ -209,11 +224,11 @@ std::optional<nlohmann::json> Reflector::GenerateTemplateArguments() const {
     return std::nullopt;
   }
 
+  auto execution_model = entrypoints.front().execution_model;
   {
     root["entrypoint"] = options_.entry_point_name;
     root["shader_name"] = options_.shader_name;
-    root["shader_stage"] =
-        ExecutionModelToString(entrypoints.front().execution_model);
+    root["shader_stage"] = ExecutionModelToString(execution_model);
     root["header_file_name"] = options_.header_file_name;
   }
 
@@ -315,7 +330,8 @@ std::optional<nlohmann::json> Reflector::GenerateTemplateArguments() const {
         });
   }
 
-  root["bind_prototypes"] = EmitBindPrototypes(shader_resources);
+  root["bind_prototypes"] =
+      EmitBindPrototypes(shader_resources, execution_model);
 
   return root;
 }
@@ -887,7 +903,8 @@ std::string Reflector::GetMemberNameAtIndex(
 }
 
 std::vector<Reflector::BindPrototype> Reflector::ReflectBindPrototypes(
-    const spirv_cross::ShaderResources& resources) const {
+    const spirv_cross::ShaderResources& resources,
+    spv::ExecutionModel execution_model) const {
   std::vector<BindPrototype> prototypes;
   for (const auto& uniform_buffer : resources.uniform_buffers) {
     auto& proto = prototypes.emplace_back(BindPrototype{});
@@ -900,7 +917,7 @@ std::vector<Reflector::BindPrototype> Reflector::ReflectBindPrototypes(
       proto.docstring = stream.str();
     }
     proto.args.push_back(BindPrototypeArgument{
-        .type_name = "Command&",
+        .type_name = ExecutionModelToCommandTypeName(execution_model),
         .argument_name = "command",
     });
     proto.args.push_back(BindPrototypeArgument{
@@ -919,7 +936,7 @@ std::vector<Reflector::BindPrototype> Reflector::ReflectBindPrototypes(
       proto.docstring = stream.str();
     }
     proto.args.push_back(BindPrototypeArgument{
-        .type_name = "Command&",
+        .type_name = ExecutionModelToCommandTypeName(execution_model),
         .argument_name = "command",
     });
     proto.args.push_back(BindPrototypeArgument{
@@ -938,7 +955,7 @@ std::vector<Reflector::BindPrototype> Reflector::ReflectBindPrototypes(
       proto.docstring = stream.str();
     }
     proto.args.push_back(BindPrototypeArgument{
-        .type_name = "Command&",
+        .type_name = ExecutionModelToCommandTypeName(execution_model),
         .argument_name = "command",
     });
     proto.args.push_back(BindPrototypeArgument{
@@ -992,8 +1009,9 @@ std::vector<Reflector::BindPrototype> Reflector::ReflectBindPrototypes(
 }
 
 nlohmann::json::array_t Reflector::EmitBindPrototypes(
-    const spirv_cross::ShaderResources& resources) const {
-  const auto prototypes = ReflectBindPrototypes(resources);
+    const spirv_cross::ShaderResources& resources,
+    spv::ExecutionModel execution_model) const {
+  const auto prototypes = ReflectBindPrototypes(resources, execution_model);
   nlohmann::json::array_t result;
   for (const auto& res : prototypes) {
     auto& item = result.emplace_back(nlohmann::json::object_t{});

impeller/compiler/reflector.h

@@ -118,10 +118,12 @@ class Reflector {
       const spirv_cross::TypeID& type_id) const;
 
   std::vector<BindPrototype> ReflectBindPrototypes(
-      const spirv_cross::ShaderResources& resources) const;
+      const spirv_cross::ShaderResources& resources,
+      spv::ExecutionModel execution_model) const;
 
   nlohmann::json::array_t EmitBindPrototypes(
-      const spirv_cross::ShaderResources& resources) const;
+      const spirv_cross::ShaderResources& resources,
+      spv::ExecutionModel execution_model) const;
 
   std::optional<StructDefinition> ReflectPerVertexStructDefinition(
       const spirv_cross::SmallVector<spirv_cross::Resource>& stage_inputs)