dawn.node: add support for the experimental subgroup extensions.

In addition to adding the FeatureName enums, it adds a new IDL file,
DawnExtensions.idl that's merged along with Browser.idl and webgpu.idl
and will contain IDL for Dawn-specific extensions.

Also updates idlgen to support merging enums.

Bug: dawn:464
Change-Id: I02bd8e210c52dda038f0fac68bbcc275274cd74b
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/146387
Reviewed-by: Ben Clayton <[email protected]>
Kokoro: Kokoro <[email protected]>
Commit-Queue: Corentin Wallez <[email protected]>

Author: Kangz

src/dawn/node/binding/Converter.cpp

@@ -1610,6 +1610,12 @@ bool Converter::Convert(wgpu::FeatureName& out, interop::GPUFeatureName in) {
         case interop::GPUFeatureName::kFloat32Filterable:
             out = wgpu::FeatureName::Float32Filterable;
             return true;
+        case interop::GPUFeatureName::kChromiumExperimentalSubgroups:
+            out = wgpu::FeatureName::ChromiumExperimentalSubgroups;
+            return true;
+        case interop::GPUFeatureName::kChromiumExperimentalSubgroupUniformControlFlow:
+            out = wgpu::FeatureName::ChromiumExperimentalSubgroupUniformControlFlow;
+            return true;
     }
     return false;
 }
@@ -1649,6 +1655,12 @@ bool Converter::Convert(interop::GPUFeatureName& out, wgpu::FeatureName in) {
         case wgpu::FeatureName::Float32Filterable:
             out = interop::GPUFeatureName::kFloat32Filterable;
             return true;
+        case wgpu::FeatureName::ChromiumExperimentalSubgroups:
+            out = interop::GPUFeatureName::kChromiumExperimentalSubgroups;
+            return true;
+        case wgpu::FeatureName::ChromiumExperimentalSubgroupUniformControlFlow:
+            out = interop::GPUFeatureName::kChromiumExperimentalSubgroupUniformControlFlow;
+            return true;
 
         case wgpu::FeatureName::PipelineStatisticsQuery:
         case wgpu::FeatureName::DawnInternalUsages:

src/dawn/node/interop/CMakeLists.txt

@@ -23,6 +23,7 @@ idlgen(
     IDLS
         "${CMAKE_CURRENT_SOURCE_DIR}/Browser.idl"
         "${WEBGPU_IDL_PATH}"
+        "${CMAKE_CURRENT_SOURCE_DIR}/DawnExtensions.idl"
     DEPENDS
         "${CMAKE_CURRENT_SOURCE_DIR}/WebGPUCommon.tmpl"
     OUTPUT
@@ -35,6 +36,7 @@ idlgen(
     IDLS
         "${CMAKE_CURRENT_SOURCE_DIR}/Browser.idl"
         "${WEBGPU_IDL_PATH}"
+        "${CMAKE_CURRENT_SOURCE_DIR}/DawnExtensions.idl"
     DEPENDS
         "${CMAKE_CURRENT_SOURCE_DIR}/WebGPUCommon.tmpl"
     OUTPUT

src/dawn/node/interop/DawnExtensions.idl

@@ -0,0 +1,21 @@
+// Copyright 2023 The Dawn Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// An IDL file that adds support for Dawn extensions that are not part of the
+// upstream webgpu.idl.
+
+enum GPUFeatureName {
+    "chromium-experimental-subgroups",
+    "chromium-experimental-subgroup-uniform-control-flow",
+};

tools/src/cmd/idlgen/main.go

@@ -205,6 +205,7 @@ func simplify(in *ast.File) (*ast.File, declarations) {
 		interfaces := map[string]*ast.Interface{}
 		mixins := map[string]*ast.Mixin{}
 		includes := []*ast.Includes{}
+		enums := map[string]*ast.Enum{}
 		for _, d := range in.Declarations {
 			switch d := d.(type) {
 			case *ast.Interface:
@@ -222,6 +223,16 @@ func simplify(in *ast.File) (*ast.File, declarations) {
 				s.declarations[d.Name] = d
 			case *ast.Includes:
 				includes = append(includes, d)
+			case *ast.Enum:
+				if e, ok := enums[d.Name]; ok {
+					// Merge partial enums into one enum
+					e.Values = append(e.Values, d.Values...)
+				} else {
+					clone := *d
+					d := &clone
+					enums[d.Name] = d
+					s.declarations[d.Name] = d
+				}
 			default:
 				if name := nameOf(d); name != "" {
 					s.declarations[nameOf(d)] = d