Support HLSL ingestion in ImpellerC (flutter/engine#37461)

engine/src/flutter/impeller/compiler/compiler.cc

@@ -265,12 +265,24 @@ Compiler::Compiler(const fml::Mapping& source_mapping,
   // here are irrelevant and get in the way of generating reflection code.
   spirv_options.SetGenerateDebugInfo();
 
-  // Expects GLSL 4.60 (Core Profile).
-  // https://www.khronos.org/registry/OpenGL/specs/gl/GLSLangSpec.4.60.pdf
-  spirv_options.SetSourceLanguage(
-      shaderc_source_language::shaderc_source_language_glsl);
-  spirv_options.SetForcedVersionProfile(460,
-                                        shaderc_profile::shaderc_profile_core);
+  switch (options_.source_language) {
+    case SourceLanguage::kGLSL:
+      // Expects GLSL 4.60 (Core Profile).
+      // https://www.khronos.org/registry/OpenGL/specs/gl/GLSLangSpec.4.60.pdf
+      spirv_options.SetSourceLanguage(
+          shaderc_source_language::shaderc_source_language_glsl);
+      spirv_options.SetForcedVersionProfile(
+          460, shaderc_profile::shaderc_profile_core);
+      break;
+    case SourceLanguage::kHLSL:
+      spirv_options.SetSourceLanguage(
+          shaderc_source_language::shaderc_source_language_hlsl);
+      break;
+    case SourceLanguage::kUnknown:
+      COMPILER_ERROR << "Source language invalid.";
+      return;
+  }
+
   SetLimitations(spirv_options);
 
   switch (source_options.target_platform) {
@@ -347,7 +359,9 @@ Compiler::Compiler(const fml::Mapping& source_mapping,
 
   shaderc::Compiler spv_compiler;
   if (!spv_compiler.IsValid()) {
-    COMPILER_ERROR << "Could not initialize the GLSL to SPIRV compiler.";
+    COMPILER_ERROR << "Could not initialize the "
+                   << SourceLanguageToString(options_.source_language)
+                   << " to SPIRV compiler.";
     return;
   }
 
@@ -364,7 +378,8 @@ Compiler::Compiler(const fml::Mapping& source_mapping,
           ));
   if (spv_result_->GetCompilationStatus() !=
       shaderc_compilation_status::shaderc_compilation_status_success) {
-    COMPILER_ERROR << "GLSL to SPIRV failed; "
+    COMPILER_ERROR << SourceLanguageToString(options_.source_language)
+                   << " to SPIRV failed; "
                    << ShaderCErrorToString(spv_result_->GetCompilationStatus())
                    << ". " << spv_result_->GetNumErrors() << " error(s) and "
                    << spv_result_->GetNumWarnings() << " warning(s).";

engine/src/flutter/impeller/compiler/compiler_test.cc

@@ -66,19 +66,21 @@ std::unique_ptr<fml::FileMapping> CompilerTest::GetReflectionJson(
 }
 
 bool CompilerTest::CanCompileAndReflect(const char* fixture_name,
-                                        SourceType source_type) const {
+                                        SourceType source_type,
+                                        SourceLanguage source_language) const {
   auto fixture = flutter::testing::OpenFixtureAsMapping(fixture_name);
-  if (!fixture->GetMapping()) {
+  if (!fixture || !fixture->GetMapping()) {
     VALIDATION_LOG << "Could not find shader in fixtures: " << fixture_name;
     return false;
   }
 
   SourceOptions source_options(fixture_name, source_type);
   source_options.target_platform = GetParam();
+  source_options.source_language = source_language;
   source_options.working_directory = std::make_shared<fml::UniqueFD>(
       flutter::testing::OpenFixturesDirectory());
   source_options.entry_point_name = EntryPointFunctionNameFromSourceName(
-      fixture_name, SourceTypeFromFileName(fixture_name));
+      fixture_name, SourceTypeFromFileName(fixture_name), source_language);
 
   Reflector::Options reflector_options;
   reflector_options.header_file_name = ReflectionHeaderName(fixture_name);

engine/src/flutter/impeller/compiler/compiler_test.h

@@ -26,7 +26,8 @@ class CompilerTest : public ::testing::TestWithParam<TargetPlatform> {
 
   bool CanCompileAndReflect(
       const char* fixture_name,
-      SourceType source_type = SourceType::kUnknown) const;
+      SourceType source_type = SourceType::kUnknown,
+      SourceLanguage source_language = SourceLanguage::kGLSL) const;
 
  private:
   fml::UniqueFD intermediates_directory_;

engine/src/flutter/impeller/compiler/compiler_unittests.cc

@@ -28,6 +28,13 @@ TEST(CompilerTest, ShaderKindMatchingIsSuccessful) {
 TEST_P(CompilerTest, CanCompile) {
   ASSERT_TRUE(CanCompileAndReflect("sample.vert"));
   ASSERT_TRUE(CanCompileAndReflect("sample.vert", SourceType::kVertexShader));
+  ASSERT_TRUE(CanCompileAndReflect("sample.vert", SourceType::kVertexShader,
+                                   SourceLanguage::kGLSL));
+}
+
+TEST_P(CompilerTest, CanCompileHLSL) {
+  ASSERT_TRUE(CanCompileAndReflect(
+      "simple.vert.hlsl", SourceType::kVertexShader, SourceLanguage::kHLSL));
 }
 
 TEST_P(CompilerTest, CanCompileTessellationControlShader) {

engine/src/flutter/impeller/compiler/impellerc_main.cc

@@ -59,6 +59,7 @@ bool Main(const fml::CommandLine& command_line) {
 
   SourceOptions options;
   options.target_platform = switches.target_platform;
+  options.source_language = switches.source_language;
   if (switches.input_type == SourceType::kUnknown) {
     options.type = SourceTypeFromFileName(switches.source_file_name);
   } else {
@@ -69,7 +70,7 @@ bool Main(const fml::CommandLine& command_line) {
   options.include_dirs = switches.include_directories;
   options.defines = switches.defines;
   options.entry_point_name = EntryPointFunctionNameFromSourceName(
-      switches.source_file_name, options.type);
+      switches.source_file_name, options.type, options.source_language);
   options.json_format = switches.json_format;
 
   Reflector::Options reflector_options;

engine/src/flutter/impeller/compiler/source_options.h

@@ -19,6 +19,7 @@ namespace compiler {
 struct SourceOptions {
   SourceType type = SourceType::kUnknown;
   TargetPlatform target_platform = TargetPlatform::kUnknown;
+  SourceLanguage source_language = SourceLanguage::kUnknown;
   std::shared_ptr<fml::UniqueFD> working_directory;
   std::vector<IncludeDir> include_dirs;
   std::string file_name = "main.glsl";

engine/src/flutter/impeller/compiler/switches.cc

@@ -4,10 +4,13 @@
 
 #include "impeller/compiler/switches.h"
 
+#include <algorithm>
+#include <cctype>
 #include <filesystem>
 #include <map>
 
 #include "flutter/fml/file.h"
+#include "impeller/compiler/types.h"
 #include "impeller/compiler/utilities.h"
 
 namespace impeller {
@@ -44,7 +47,7 @@ void Switches::PrintHelp(std::ostream& stream) {
     stream << " --" << platform.first;
   }
   stream << " ]" << std::endl;
-  stream << "--input=<glsl_file>" << std::endl;
+  stream << "--input=<source_file>" << std::endl;
   stream << "[optional] --input-kind={";
   for (const auto& source_type : kKnownSourceTypes) {
     stream << source_type.first << ", ";
@@ -52,6 +55,8 @@ void Switches::PrintHelp(std::ostream& stream) {
   stream << "}" << std::endl;
   stream << "--sl=<sl_output_file>" << std::endl;
   stream << "--spirv=<spirv_output_file>" << std::endl;
+  stream << "[optional] --source-language=glsl|hlsl (default: glsl)"
+         << std::endl;
   stream << "[optional] --iplr (causes --sl file to be emitted in iplr format)"
          << std::endl;
   stream << "[optional] --reflection-json=<reflection_json_file>" << std::endl;
@@ -120,6 +125,16 @@ Switches::Switches(const fml::CommandLine& command_line)
     return;
   }
 
+  auto language =
+      command_line.GetOptionValueWithDefault("source-language", "glsl");
+  std::transform(language.begin(), language.end(), language.begin(),
+                 [](char x) { return std::tolower(x); });
+  if (language == "glsl") {
+    source_language = SourceLanguage::kGLSL;
+  } else if (language == "hlsl") {
+    source_language = SourceLanguage::kHLSL;
+  }
+
   for (const auto& include_dir_path : command_line.GetOptionValues("include")) {
     if (!include_dir_path.data()) {
       continue;
@@ -161,6 +176,11 @@ bool Switches::AreValid(std::ostream& explain) const {
     valid = false;
   }
 
+  if (source_language == SourceLanguage::kUnknown) {
+    explain << "Invalid source language type." << std::endl;
+    valid = false;
+  }
+
   if (!working_directory || !working_directory->is_valid()) {
     explain << "Could not figure out working directory." << std::endl;
     valid = false;

engine/src/flutter/impeller/compiler/switches.h

@@ -32,6 +32,7 @@ struct Switches {
   std::string depfile_path;
   std::vector<std::string> defines;
   bool json_format;
+  SourceLanguage source_language = SourceLanguage::kUnknown;
 
   Switches();
 

engine/src/flutter/impeller/compiler/switches_unittests.cc

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <initializer_list>
+#include <vector>
+
 #include "flutter/fml/command_line.h"
 #include "flutter/fml/file.h"
 #include "flutter/testing/testing.h"
@@ -12,6 +15,19 @@ namespace impeller {
 namespace compiler {
 namespace testing {
 
+Switches MakeSwitchesDesktopGL(
+    std::initializer_list<const char*> additional_options = {}) {
+  std::vector<const char*> options = {"--opengl-desktop", "--input=input.vert",
+                                      "--sl=output.vert",
+                                      "--spirv=output.spirv"};
+  options.insert(options.end(), additional_options.begin(),
+                 additional_options.end());
+
+  auto cl = fml::CommandLineFromIteratorsWithArgv0("impellerc", options.begin(),
+                                                   options.end());
+  return Switches(cl);
+}
+
 TEST(SwitchesTest, DoesntMangleUnicodeIncludes) {
   const char* directory_name = "test_shader_include_Ã<EFBFBD>";
   fml::CreateDirectory(flutter::testing::OpenFixturesDirectory(),
@@ -21,16 +37,26 @@ TEST(SwitchesTest, DoesntMangleUnicodeIncludes) {
       std::string(flutter::testing::GetFixturesPath()) + "/" + directory_name;
   auto include_option = "--include=" + include_path;
 
-  const auto cl = fml::CommandLineFromInitializerList(
-      {"impellerc", "--opengl-desktop", "--input=input.vert",
-       "--sl=output.vert", "--spirv=output.spirv", include_option.c_str()});
-  Switches switches(cl);
+  Switches switches = MakeSwitchesDesktopGL({include_option.c_str()});
+
   ASSERT_TRUE(switches.AreValid(std::cout));
   ASSERT_EQ(switches.include_directories.size(), 1u);
   ASSERT_NE(switches.include_directories[0].dir, nullptr);
   ASSERT_EQ(switches.include_directories[0].name, include_path);
 }
 
+TEST(SwitchesTest, SourceLanguageDefaultsToGLSL) {
+  Switches switches = MakeSwitchesDesktopGL();
+  ASSERT_TRUE(switches.AreValid(std::cout));
+  ASSERT_EQ(switches.source_language, SourceLanguage::kGLSL);
+}
+
+TEST(SwitchesTest, SourceLanguageCanBeSetToHLSL) {
+  Switches switches = MakeSwitchesDesktopGL({"--source-language=hLsL"});
+  ASSERT_TRUE(switches.AreValid(std::cout));
+  ASSERT_EQ(switches.source_language, SourceLanguage::kHLSL);
+}
+
 }  // namespace testing
 }  // namespace compiler
 }  // namespace impeller

engine/src/flutter/impeller/compiler/types.cc

@@ -74,8 +74,25 @@ std::string TargetPlatformToString(TargetPlatform platform) {
   FML_UNREACHABLE();
 }
 
-std::string EntryPointFunctionNameFromSourceName(const std::string& file_name,
-                                                 SourceType type) {
+std::string SourceLanguageToString(SourceLanguage source_language) {
+  switch (source_language) {
+    case SourceLanguage::kUnknown:
+      return "Unknown";
+    case SourceLanguage::kGLSL:
+      return "GLSL";
+    case SourceLanguage::kHLSL:
+      return "HLSL";
+  }
+}
+
+std::string EntryPointFunctionNameFromSourceName(
+    const std::string& file_name,
+    SourceType type,
+    SourceLanguage source_language) {
+  if (source_language == SourceLanguage::kHLSL) {
+    return "main";
+  }
+
   std::stringstream stream;
   std::filesystem::path file_path(file_name);
   stream << Utf8FromPath(file_path.stem()) << "_";

engine/src/flutter/impeller/compiler/types.h

@@ -37,6 +37,12 @@ enum class TargetPlatform {
   kSkSL,
 };
 
+enum class SourceLanguage {
+  kUnknown,
+  kGLSL,
+  kHLSL,
+};
+
 bool TargetPlatformIsMetal(TargetPlatform platform);
 
 bool TargetPlatformIsOpenGL(TargetPlatform platform);
@@ -47,10 +53,14 @@ std::string SourceTypeToString(SourceType type);
 
 std::string TargetPlatformToString(TargetPlatform platform);
 
+std::string SourceLanguageToString(SourceLanguage source_language);
+
 std::string TargetPlatformSLExtension(TargetPlatform platform);
 
-std::string EntryPointFunctionNameFromSourceName(const std::string& file_name,
-                                                 SourceType type);
+std::string EntryPointFunctionNameFromSourceName(
+    const std::string& file_name,
+    SourceType type,
+    SourceLanguage source_language);
 
 bool TargetPlatformNeedsSL(TargetPlatform platform);
 

engine/src/flutter/impeller/fixtures/BUILD.gn

@@ -61,6 +61,7 @@ test_fixtures("file_fixtures") {
     "sample.tese",
     "sample.vert",
     "sample_with_binding.vert",
+    "simple.vert.hlsl",
     "sa%m#ple.vert",
     "struct_def_bug.vert",
     "table_mountain_nx.png",

engine/src/flutter/impeller/fixtures/simple.vert.hlsl

@@ -0,0 +1,18 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+struct VertexInput {
+  float3 position : POSITION;
+};
+
+struct VertexOutput {
+  float4 position : SV_POSITION;
+};
+
+VertexOutput
+main(VertexInput input) {
+  VertexOutput output;
+  output.position = float4(input.position, 1.0);
+  return output;
+}