// Copyright Epic Games, Inc. All Rights Reserved.

#include "ShaderConductorContext.h"
#include "HAL/ExceptionHandling.h"

#if PLATFORM_MAC || PLATFORM_WINDOWS || PLATFORM_LINUX
THIRD_PARTY_INCLUDES_START
	#include "ShaderConductor/ShaderConductor.hpp"
THIRD_PARTY_INCLUDES_END
#endif


ESCWErrorCode GSCWErrorCode = ESCWErrorCode::NotSet;

namespace CrossCompiler
{

#if PLATFORM_MAC || PLATFORM_WINDOWS || PLATFORM_LINUX

	// Inner wrapper function is required here because '__try'-statement cannot be used with function that requires object unwinding
	static void InnerScRewriteWrapper(
		const ShaderConductor::Compiler::SourceDesc& InSourceDesc,
		const ShaderConductor::Compiler::Options& InOptions,
		ShaderConductor::Compiler::ResultDesc& OutResultDesc)
	{
		OutResultDesc = ShaderConductor::Compiler::Rewrite(InSourceDesc, InOptions);
	}

	static bool ScRewriteWrapper(
		const ShaderConductor::Compiler::SourceDesc& InSourceDesc,
		const ShaderConductor::Compiler::Options& InOptions,
		ShaderConductor::Compiler::ResultDesc& OutResultDesc,
		bool& bOutException)
	{
		bOutException = false;
#if !PLATFORM_SEH_EXCEPTIONS_DISABLED
		__try
#endif
		{
			InnerScRewriteWrapper(InSourceDesc, InOptions, OutResultDesc);
			return true;
		}
#if !PLATFORM_SEH_EXCEPTIONS_DISABLED
		__except (EXCEPTION_EXECUTE_HANDLER)
		{
			GSCWErrorCode = ESCWErrorCode::CrashInsidePlatformCompiler;
			FMemory::Memzero(OutResultDesc);
			bOutException = true;
			return false;
		}
#endif
	}

	// Inner wrapper function is required here because '__try'-statement cannot be used with function that requires object unwinding
	static void InnerScCompileWrapper(
		const ShaderConductor::Compiler::SourceDesc& InSourceDesc,
		const ShaderConductor::Compiler::Options& InOptions,
		const ShaderConductor::Compiler::TargetDesc& InTargetDesc,
		ShaderConductor::Compiler::ResultDesc& OutResultDesc)
	{
		OutResultDesc = ShaderConductor::Compiler::Compile(InSourceDesc, InOptions, InTargetDesc);
	}

	static bool ScCompileWrapper(
		const ShaderConductor::Compiler::SourceDesc& InSourceDesc,
		const ShaderConductor::Compiler::Options& InOptions,
		const ShaderConductor::Compiler::TargetDesc& InTargetDesc,
		ShaderConductor::Compiler::ResultDesc& OutResultDesc,
		bool& bOutException)
	{
		bOutException = false;
#if !PLATFORM_SEH_EXCEPTIONS_DISABLED
		__try
#endif
		{
			InnerScCompileWrapper(InSourceDesc, InOptions, InTargetDesc, OutResultDesc);
			return true;
		}
#if !PLATFORM_SEH_EXCEPTIONS_DISABLED
		__except (EXCEPTION_EXECUTE_HANDLER)
		{
			GSCWErrorCode = ESCWErrorCode::CrashInsidePlatformCompiler;
			FMemory::Memzero(OutResultDesc);
			bOutException = true;
			return false;
		}
#endif
	}

	// Inner wrapper function is required here because '__try'-statement cannot be used with function that requires object unwinding
	static void InnerScCompileWrapper(
		const ShaderConductor::Compiler::ResultDesc& InBinaryDesc,
		const ShaderConductor::Compiler::SourceDesc& InSourceDesc,
		const ShaderConductor::Compiler::TargetDesc& InTargetDesc,
		const ShaderConductor::Compiler::Options& InOptions,
		ShaderConductor::Compiler::ResultDesc& OutResultDesc)
	{
		OutResultDesc = ShaderConductor::Compiler::ConvertBinary(InBinaryDesc, InSourceDesc, InOptions, InTargetDesc);
	}

	static bool ScConvertBinaryWrapper(
		const ShaderConductor::Compiler::ResultDesc& InBinaryDesc,
		const ShaderConductor::Compiler::SourceDesc& InSourceDesc,
		const ShaderConductor::Compiler::TargetDesc& InTargetDesc,
		const ShaderConductor::Compiler::Options& InOptions,
		ShaderConductor::Compiler::ResultDesc& OutResultDesc,
		bool& bOutException)
	{
		bOutException = false;
#if !PLATFORM_SEH_EXCEPTIONS_DISABLED
		__try
#endif
		{
			InnerScCompileWrapper(InBinaryDesc, InSourceDesc, InTargetDesc, InOptions, OutResultDesc);
			return true;
		}
#if !PLATFORM_SEH_EXCEPTIONS_DISABLED
		__except (EXCEPTION_EXECUTE_HANDLER)
		{
			GSCWErrorCode = ESCWErrorCode::CrashInsidePlatformCompiler;
			FMemory::Memzero(OutResultDesc);
			bOutException = true;
			return false;
		}
#endif
	}

	// Converts the byte array 'InString' (without null terminator) to the output ANSI string 'OutString' (with appended null terminator).
	static void ConvertByteArrayToAnsiString(const ANSICHAR* InString, uint32 InStringLength, TArray<ANSICHAR>& OutString)
	{
		// 'FCStringAnsi::Strncpy()' will put a '\0' character at the end
		OutString.SetNum(InStringLength + 1);
		FCStringAnsi::Strncpy(OutString.GetData(), InString, OutString.Num());
	}

	// Converts the FString to the output ANSI string 'OutString'.
	static void ConvertFStringToAnsiString(const FString& InString, TArray<ANSICHAR>& OutString)
	{
		ConvertByteArrayToAnsiString(TCHAR_TO_ANSI(*InString), InString.Len(), OutString);
	}

	// Copies the NULL-terminated string 'InString' to 'OutString'. Also copies the '\0' character at the end.
	static void CopyAnsiString(const ANSICHAR* InString, TArray<ANSICHAR>& OutString)
	{
		// 'InString' is NULL-terminated, so we can use 'FCStringAnsi::Strlen()'
		if (InString != nullptr)
		{
			ConvertByteArrayToAnsiString(InString, FCStringAnsi::Strlen(InString), OutString);
		}
	}

	// Converts the specified ShaderConductor blob to FString.
	static bool ConvertByteArrayToFString(const void* InData, uint32 InSize, FString& OutString)
	{
		if (InData != nullptr && InSize > 0)
		{
			FUTF8ToTCHAR UTF8Converter(reinterpret_cast<const ANSICHAR*>(InData), InSize);
			OutString = FString(UTF8Converter.Length(), UTF8Converter.Get());
			return true;
		}
		return false;
	}

	// Converts the specified ShaderConductor blob to FString.
	static bool ConvertScBlobToFString(ShaderConductor::Blob* Blob, FString& OutString)
	{
		if (Blob && Blob->Size() > 0)
		{
			return ConvertByteArrayToFString(Blob->Data(), Blob->Size(), OutString);
		}
		return false;
	}

	static ShaderConductor::ShaderStage ToShaderConductorShaderStage(EShaderFrequency Frequency)
	{
		check(Frequency >= SF_Vertex && Frequency <= SF_RayCallable);
		switch (Frequency)
		{
		case SF_Vertex:			return ShaderConductor::ShaderStage::VertexShader;
		case SF_Mesh:			checkf(0, TEXT("SF_Mesh not support in ShaderConductor")); break;
		case SF_Amplification:	checkf(0, TEXT("SF_Amplification not support in ShaderConductor")); break;
		case SF_Pixel:			return ShaderConductor::ShaderStage::PixelShader;
		case SF_Geometry:		return ShaderConductor::ShaderStage::GeometryShader;
		case SF_Compute:		return ShaderConductor::ShaderStage::ComputeShader;

		case SF_RayGen:			return ShaderConductor::ShaderStage::RayGen;
		case SF_RayMiss:		return ShaderConductor::ShaderStage::RayMiss;
		case SF_RayHitGroup:	return ShaderConductor::ShaderStage::RayHitGroup;
		case SF_RayCallable:	return ShaderConductor::ShaderStage::RayCallable;

		default: break;
		}
		return ShaderConductor::ShaderStage::NumShaderStages;
	}

	// Wrapper structure to hold all intermediate buffers for ShaderConductor
	struct FShaderConductorContext::FShaderConductorIntermediates
	{
		FShaderConductorIntermediates()
			: Stage(ShaderConductor::ShaderStage::NumShaderStages)
		{
		}

		TArray<ANSICHAR> ShaderSource;
		TArray<ANSICHAR> Filename;
		TArray<ANSICHAR> EntryPoint;
		ShaderConductor::ShaderStage Stage;
		TArray<TPair<TArray<ANSICHAR>, TArray<ANSICHAR>>> Defines;
		TArray<ShaderConductor::MacroDefine> DefineRefs;
		TArray<TPair<TArray<ANSICHAR>, TArray<ANSICHAR>>> Flags;
		TArray<ShaderConductor::MacroDefine> FlagRefs;
		TArray<TArray<ANSICHAR>> CustomDxcArgs;
		TArray<ANSICHAR const*> CustomDxcArgRefs;
		TArray<ANSICHAR const*> DxcArgRefs;
	};

	static void ConvertScSourceDesc(const FShaderConductorContext::FShaderConductorIntermediates& Intermediates, ShaderConductor::Compiler::SourceDesc& OutSourceDesc)
	{
		// Convert descriptor with pointers to the ANSI strings
		OutSourceDesc.source = Intermediates.ShaderSource.GetData();
		OutSourceDesc.fileName = Intermediates.Filename.GetData();
		OutSourceDesc.entryPoint = Intermediates.EntryPoint.GetData();
		OutSourceDesc.stage = Intermediates.Stage;
		if (Intermediates.DefineRefs.Num() > 0)
		{
			OutSourceDesc.defines = Intermediates.DefineRefs.GetData();
			OutSourceDesc.numDefines = static_cast<uint32>(Intermediates.DefineRefs.Num());
		}
		else
		{
			OutSourceDesc.defines = nullptr;
			OutSourceDesc.numDefines = 0;
		}
	}

	static const ANSICHAR* GetHlslVersionString(int32 Version)
	{
		switch (Version)
		{
		case 50: return "50";
		case 60: return "60";
		case 61: return "61";
		case 62: return "62";
		case 63: return "63";
		case 64: return "64";
		case 65: return "65";
		case 66: return "66";
		default: return nullptr;
		}
	}

	static void ConvertScTargetDescLanguageHlsl(const FShaderConductorTarget& InTarget, ShaderConductor::Compiler::TargetDesc& OutTargetDesc)
	{
		OutTargetDesc.language = ShaderConductor::ShadingLanguage::Hlsl;
		OutTargetDesc.version = GetHlslVersionString(InTarget.Version);
		checkf(OutTargetDesc.version, TEXT("Unsupported target shader version for HLSL: SM%d.%d"), InTarget.Version / 10, InTarget.Version % 10);
	}

	static const ANSICHAR* GetGlslFamilyVersionString(int32 Version)
	{
		switch (Version)
		{
		//ESSL
		case 310: return "310";
		case 320: return "320";
		//GLSL
		case 330: return "330";
		case 430: return "430";
		case 440: return "440";
		case 450: return "450";
		case 460: return "460";
		default: return nullptr;
		}
	}

	static void ConvertScTargetDescLanguageGlslFamily(const FShaderConductorTarget& InTarget, ShaderConductor::Compiler::TargetDesc& OutTargetDesc)
	{
		OutTargetDesc.language = (InTarget.Language == EShaderConductorLanguage::Glsl ? ShaderConductor::ShadingLanguage::Glsl : ShaderConductor::ShadingLanguage::Essl);
		OutTargetDesc.version = GetGlslFamilyVersionString(InTarget.Version);
		checkf(OutTargetDesc.version, TEXT("Unsupported target shader version for GLSL family: %d"), InTarget.Version);
	}

	static const ANSICHAR* GetMetalFamilyVersionString(int32 Version)
	{
		switch (Version)
		{
		case 20400: return "20400";
		case 20300: return "20300";
		case 20200: return "20200";
		case 20100: return "20100";
		case 20000: return "20000";
		case 10200: return "10200";
		case 10100: return "10100";
		case 10000: return "10000";
		default: return nullptr;
		}
	}

	static void ConvertScTargetDescLanguageMetalFamily(const FShaderConductorTarget& InTarget, ShaderConductor::Compiler::TargetDesc& OutTargetDesc)
	{
		OutTargetDesc.language = (InTarget.Language == EShaderConductorLanguage::Metal_macOS ? ShaderConductor::ShadingLanguage::Msl_macOS : ShaderConductor::ShadingLanguage::Msl_iOS);
		OutTargetDesc.version = GetMetalFamilyVersionString(InTarget.Version);
		checkf(OutTargetDesc.version, TEXT("Unsupported target shader version for Metal family: %d"), InTarget.Version);
	}

	// Converts an array of FString to a C-style array of char* pointers
	static void ConvertStringArrayToAnsiArray(const TArray<FString>& InPairs, TArray<TArray<ANSICHAR>>& OutPairs, TArray<const char*>& OutPairRefs)
	{
		// Convert map into an array container
		TArray<ANSICHAR> Value;
		for (const FString& Iter : InPairs)
		{
			ConvertFStringToAnsiString(Iter, Value);
			OutPairs.Emplace(MoveTemp(Value));
		}

		// Store references after all elements have been added to the container so the pointers remain valid
		OutPairRefs.SetNum(OutPairs.Num());
		for (int32 Index = 0; Index < OutPairs.Num(); ++Index)
		{
			OutPairRefs[Index] = OutPairs[Index].GetData();
		}
	}

	// Converts a map of string pairs to a C-Style macro defines array
	static void ConvertStringMapToMacroDefines(const TMap<FString,FString>& InPairs, TArray<TPair<TArray<ANSICHAR>, TArray<ANSICHAR>>>& OutPairs, TArray<ShaderConductor::MacroDefine>& OutPairRefs)
	{
		// Convert map into an array container
		TArray<ANSICHAR> Name, Value;
		for (const TPair<FString, FString>& Iter : InPairs)
		{
			ConvertFStringToAnsiString(Iter.Key, Name);
			ConvertFStringToAnsiString(Iter.Value, Value);
			OutPairs.Emplace(MoveTemp(Name), MoveTemp(Value));
		}

		// Store references after all elements have been added to the container so the pointers remain valid
		OutPairRefs.SetNum(OutPairs.Num());
		for (int32 Index = 0; Index < OutPairs.Num(); ++Index)
		{
			OutPairRefs[Index].name = OutPairs[Index].Key.GetData();
			OutPairRefs[Index].value = OutPairs[Index].Value.GetData();
		}
	}

	static void ConvertScTargetDesc(FShaderConductorContext::FShaderConductorIntermediates& Intermediates, const FShaderConductorTarget& InTarget, ShaderConductor::Compiler::TargetDesc& OutTargetDesc)
	{
		// Convert FString to ANSI string and store them as intermediates
		FMemory::Memzero(OutTargetDesc);

		Intermediates.Flags.Empty();
		Intermediates.FlagRefs.Empty();

		switch (InTarget.Language)
		{
		case EShaderConductorLanguage::Hlsl:
			ConvertScTargetDescLanguageHlsl(InTarget, OutTargetDesc);
			break;
		case EShaderConductorLanguage::Glsl:
		case EShaderConductorLanguage::Essl:
			ConvertScTargetDescLanguageGlslFamily(InTarget, OutTargetDesc);
			break;
		case EShaderConductorLanguage::Metal_macOS:
		case EShaderConductorLanguage::Metal_iOS:
			ConvertScTargetDescLanguageMetalFamily(InTarget, OutTargetDesc);
			break;
		}

		// Convert flags map into an array container
		ConvertStringMapToMacroDefines(InTarget.CompileFlags.GetDefinitionMap(), Intermediates.Flags, Intermediates.FlagRefs);

		OutTargetDesc.options = Intermediates.FlagRefs.GetData();
		OutTargetDesc.numOptions = static_cast<uint32>(Intermediates.FlagRefs.Num());

		// Wrap input function into lambda to convert to ShaderConductor interface
		if (InTarget.VariableTypeRenameCallback)
		{
			OutTargetDesc.variableTypeRenameCallback = [InnerCallback = InTarget.VariableTypeRenameCallback](const char* VariableName, const char* TypeName) -> ShaderConductor::Blob
			{
				// Forward callback to public interface callback
				FString RenamedTypeName;
				if (InnerCallback(FAnsiStringView(VariableName), FAnsiStringView(TypeName), RenamedTypeName))
				{
					if (!RenamedTypeName.IsEmpty())
					{
						// Convert renamed type name from FString to ShaderConductor::Blob
						return ShaderConductor::Blob(TCHAR_TO_ANSI(*RenamedTypeName), RenamedTypeName.Len() + 1);
					}
				}
				return ShaderConductor::Blob{};
			};
		}
	}

	static void ConvertScOptions(const FShaderConductorOptions& InOptions, ShaderConductor::Compiler::Options& OutOptions, const TArray<ANSICHAR const*>& CustomDxcArgRefs, TArray<ANSICHAR const*>& DxcArgRefs)
	{
		// Validate input shader model with respect to certain language features.
		checkf(
			(!InOptions.bEnable16bitTypes || InOptions.ShaderModel >= FHlslShaderModel{ 6, 2 }),
			TEXT("DXC option '-enable-16bit-types' only supported with SM6.2+ but SM%u.%u was specified"),
			InOptions.ShaderModel.Major, InOptions.ShaderModel.Minor
		);

		OutOptions.removeUnusedGlobals = InOptions.bRemoveUnusedGlobals;
		OutOptions.packMatricesInRowMajor = InOptions.bPackMatricesInRowMajor;
		OutOptions.enable16bitTypes = InOptions.bEnable16bitTypes;
		OutOptions.enableDebugInfo = InOptions.bEnableDebugInfo;
		OutOptions.disableOptimizations = InOptions.bDisableOptimizations;
		OutOptions.enableFMAPass = InOptions.bEnableFMAPass;
		OutOptions.enableSeparateSamplers = InOptions.bEnableSeparateSamplersInGlsl;
		OutOptions.remapAttributeLocations = InOptions.bRemapAttributeLocations;
		OutOptions.shaderModel = ShaderConductor::Compiler::ShaderModel
		{
			static_cast<uint8>(InOptions.ShaderModel.Major),
			static_cast<uint8>(InOptions.ShaderModel.Minor)
		};

		DxcArgRefs.Empty();

		// Select language version
		DxcArgRefs.Add("-spirv");
		DxcArgRefs.Add("-Qunused-arguments");

		switch (InOptions.HlslVersion)
		{
		case 2015:
			DxcArgRefs.Add("-HV");
			DxcArgRefs.Add("2015");
			break;
		case 2016:
			DxcArgRefs.Add("-HV");
			DxcArgRefs.Add("2016");
			break;
		case 2017:
			DxcArgRefs.Add("-HV");
			DxcArgRefs.Add("2017");
			break;
		case 2018:
			// Default
			break;
		case 2021:
			DxcArgRefs.Add("-HV");
			DxcArgRefs.Add("2021");
			break;
		default:
			checkf(false, TEXT("Invalid HLSL version: expected 2015, 2016, 2017, 2018, or 2021 but %u was specified"), InOptions.HlslVersion);
			break;
		}

		// Add additional DXC arguments that are not exposed by ShaderConductor API directly
		if (InOptions.bDisableScalarBlockLayout)
		{
			DxcArgRefs.Add("-fspv-no-scalar-block-layout");
		}

		if (InOptions.bPreserveStorageInput)
		{
			DxcArgRefs.Add("-fspv-preserve-storage-input");
		}

		using ETargetEnvironment = CrossCompiler::FShaderConductorOptions::ETargetEnvironment;
		switch (InOptions.TargetEnvironment)
		{
		default:
			checkf(false, TEXT("Unexpected SPIR-V target environment: %d"), (uint32)InOptions.TargetEnvironment);
		case ETargetEnvironment::Vulkan_1_0:
			DxcArgRefs.Add("-fspv-target-env=vulkan1.0");
			break;
		case ETargetEnvironment::Vulkan_1_1:
			DxcArgRefs.Add("-fspv-target-env=vulkan1.1");
			break;
		case ETargetEnvironment::Vulkan_1_2:
			DxcArgRefs.Add("-fspv-target-env=vulkan1.2");
			break;
		}

		if (DxcArgRefs.Num() > 0)
		{
			// Use DXC argument container and append custom arguments
			DxcArgRefs.Append(CustomDxcArgRefs);
			OutOptions.numDXCArgs = DxcArgRefs.Num();
			OutOptions.DXCArgs = (const char**)DxcArgRefs.GetData();
		}
		else if (CustomDxcArgRefs.Num() > 0)
		{
			// Use custom DXC arguments only
			OutOptions.numDXCArgs = CustomDxcArgRefs.Num();
			OutOptions.DXCArgs = (const char**)CustomDxcArgRefs.GetData();
		}
		else
		{
			// No additional DXC arguments
			OutOptions.numDXCArgs = 0;
			OutOptions.DXCArgs = nullptr;
		}
	}

	// Returns whether the specified line of text contains only these characters, making it a valid line marker from DXC: ' ', '\t', '~', '^'
	static bool IsTextLineDxcLineMarker(const FString& Line)
	{
		bool bContainsLineMarkerChars = false;
		for (TCHAR Char : Line)
		{
			if (Char == TCHAR('~') || Char == TCHAR('^'))
			{
				// Line contains at least one of the necessary characters to be a potential DXC line marker.
				bContainsLineMarkerChars = true;
			}
			else if (!(Char == TCHAR(' ') || Char == TCHAR('\t')))
			{
				// Illegal character for a potential DXC line marker.
				return false;
			}
		}
		return bContainsLineMarkerChars;
	}

	// Converts the error blob from ShaderConductor into an array of error reports (of type FShaderCompilerError).
	static void ConvertScCompileErrors(ShaderConductor::Blob& ErrorBlob, TArray<FShaderCompilerError>& OutErrors)
	{
		// Convert blob into FString
		FString ErrorString;
		if (ConvertScBlobToFString(&ErrorBlob, ErrorString))
		{
			// Convert FString into array of FString (one for each line)
			TArray<FString> ErrorStringLines;
			ErrorString.ParseIntoArray(ErrorStringLines, TEXT("\n"));

			// Forward parsed array of lines to primary conversion function
			FShaderConductorContext::ConvertCompileErrors(MoveTemp(ErrorStringLines), OutErrors);
		}
	}

	FShaderConductorContext::FShaderConductorContext()
		: Intermediates(new FShaderConductorIntermediates())
	{
	}

	FShaderConductorContext::~FShaderConductorContext()
	{
		delete Intermediates;
	}

	FShaderConductorContext::FShaderConductorContext(FShaderConductorContext&& Rhs)
		: Errors(MoveTemp(Rhs.Errors))
		, Intermediates(Rhs.Intermediates)
	{
		Rhs.Intermediates = nullptr;
	}

	FShaderConductorContext& FShaderConductorContext::operator = (FShaderConductorContext&& Rhs)
	{
		Errors = MoveTemp(Rhs.Errors);
		delete Intermediates;
		Intermediates = Rhs.Intermediates;
		Rhs.Intermediates = nullptr;
		return *this;
	}

	bool FShaderConductorContext::LoadSource(const FString& ShaderSource, const FString& Filename, const FString& EntryPoint, EShaderFrequency ShaderStage, const FShaderCompilerDefinitions* Definitions, const TArray<FString>* ExtraDxcArgs)
	{
		// Convert FString to ANSI string and store them as intermediates
		ConvertFStringToAnsiString(ShaderSource, Intermediates->ShaderSource);
		ConvertFStringToAnsiString(Filename, Intermediates->Filename);
		ConvertFStringToAnsiString(EntryPoint, Intermediates->EntryPoint);

		// Convert macro definitions map into an array container
		if (Definitions != nullptr)
		{
			ConvertStringMapToMacroDefines(Definitions->GetDefinitionMap(), Intermediates->Defines, Intermediates->DefineRefs);
		}

		if (ExtraDxcArgs && ExtraDxcArgs->Num() > 0)
		{
			ConvertStringArrayToAnsiArray(*ExtraDxcArgs, Intermediates->CustomDxcArgs, Intermediates->CustomDxcArgRefs);
		}

		// Convert shader stage
		Intermediates->Stage = ToShaderConductorShaderStage(ShaderStage);

		return true;
	}

	bool FShaderConductorContext::LoadSource(const ANSICHAR* ShaderSource, const ANSICHAR* Filename, const ANSICHAR* EntryPoint, EShaderFrequency ShaderStage, const FShaderCompilerDefinitions* Definitions, const TArray<FString>* ExtraDxcArgs)
	{
		// Store ANSI strings as intermediates
		CopyAnsiString(ShaderSource, Intermediates->ShaderSource);
		CopyAnsiString(Filename, Intermediates->Filename);
		CopyAnsiString(EntryPoint, Intermediates->EntryPoint);

		// Convert macro definitions map into an array container
		if (Definitions != nullptr)
		{
			ConvertStringMapToMacroDefines(Definitions->GetDefinitionMap(), Intermediates->Defines, Intermediates->DefineRefs);
		}

		if (ExtraDxcArgs && ExtraDxcArgs->Num() > 0)
		{
			ConvertStringArrayToAnsiArray(*ExtraDxcArgs, Intermediates->CustomDxcArgs, Intermediates->CustomDxcArgRefs);
		}

		// Convert shader stage
		Intermediates->Stage = ToShaderConductorShaderStage(ShaderStage);

		return true;
	}

	bool FShaderConductorContext::RewriteHlsl(const FShaderConductorOptions& Options, FString* OutSource)
	{
		// Convert descriptors for ShaderConductor interface
		ShaderConductor::Compiler::SourceDesc ScSourceDesc;
		ConvertScSourceDesc(*Intermediates, ScSourceDesc);

		ShaderConductor::Compiler::Options ScOptions;
		ConvertScOptions(Options, ScOptions, {}, Intermediates->DxcArgRefs);

		// Rewrite HLSL with wrapper function to catch exceptions from ShaderConductor
		bool bSucceeded = false;
		bool bException = false;
		ShaderConductor::Compiler::ResultDesc ResultDesc;
		ScRewriteWrapper(ScSourceDesc, ScOptions, ResultDesc, bException);

		if (!ResultDesc.hasError && !bException && ResultDesc.target.Size() > 0)
		{
			// Copy rewritten HLSL code into intermediate source code.
			ConvertByteArrayToAnsiString(reinterpret_cast<const ANSICHAR*>(ResultDesc.target.Data()), ResultDesc.target.Size(), Intermediates->ShaderSource);

			// If output source is specified, also convert to TCHAR string
			if (OutSource != nullptr)
			{
				*OutSource = ANSI_TO_TCHAR(Intermediates->ShaderSource.GetData());
			}
			bSucceeded = true;
		}
		else
		{
			if (bException)
			{
				Errors.Add(TEXT("ShaderConductor exception during rewrite"));
			}
			bSucceeded = false;
		}

		// Append compile error and warning to output reports
		ConvertScCompileErrors(ResultDesc.errorWarningMsg, Errors);

		return bSucceeded;
	}

	bool FShaderConductorContext::CompileHlslToSpirv(const FShaderConductorOptions& Options, TArray<uint32>& OutSpirv)
	{
		// Convert descriptors for ShaderConductor interface
		ShaderConductor::Compiler::SourceDesc ScSourceDesc;
		ConvertScSourceDesc(*Intermediates, ScSourceDesc);

		ShaderConductor::Compiler::TargetDesc ScTargetDesc;
		FMemory::Memzero(ScTargetDesc);
		ScTargetDesc.language = ShaderConductor::ShadingLanguage::SpirV;

		ShaderConductor::Compiler::Options ScOptions;
		ConvertScOptions(Options, ScOptions, Intermediates->CustomDxcArgRefs, Intermediates->DxcArgRefs);

		// Compile HLSL source code to SPIR-V
		bool bSucceeded = false;
		bool bException = false;
		ShaderConductor::Compiler::ResultDesc ResultDesc;
		ScCompileWrapper(ScSourceDesc, ScOptions, ScTargetDesc, ResultDesc, bException);

		if (!ResultDesc.hasError && !bException && ResultDesc.target.Size() > 0)
		{
			// Copy result blob into output SPIR-V module
			OutSpirv = TArray<uint32>(reinterpret_cast<const uint32*>(ResultDesc.target.Data()), ResultDesc.target.Size() / 4);
			bSucceeded = true;
		}
		else
		{
			if (bException)
			{
				Errors.Add(TEXT("ShaderConductor exception during compilation"));
			}
			bSucceeded = false;
		}

		// Append compile error and warning to output reports
		ConvertScCompileErrors(ResultDesc.errorWarningMsg, Errors);

		return bSucceeded;
	}

	bool FShaderConductorContext::OptimizeSpirv(TArray<uint32>& Spirv, const ANSICHAR* const* OptConfigs, int32 OptConfigCount)
	{
		// Ignore this call if no optimization configurations were specified
		if (OptConfigCount > 0)
		{
			check(OptConfigs != nullptr);

			// Convert input SPIR-V module to Blob instance for ShaderConductor interface
			ShaderConductor::Compiler::ResultDesc SpirvInput;
			SpirvInput.target = ShaderConductor::Blob(Spirv.GetData(), Spirv.Num() * sizeof(uint32));
			SpirvInput.isText = false;
			SpirvInput.hasError = false;

			// Run optimization passes through ShaderConductor
			ShaderConductor::Compiler::ResultDesc SpirvOutput = ShaderConductor::Compiler::Optimize(SpirvInput, OptConfigs, static_cast<uint32_t>(OptConfigCount));
			if (!SpirvOutput.hasError && SpirvOutput.target.Size() > 0)
			{
				// Convert Blob instance back to our SPIR-V module
				Spirv = TArray<uint32>(reinterpret_cast<const uint32*>(SpirvOutput.target.Data()), SpirvOutput.target.Size() / 4);
			}
			else
			{
				// Extract errors
				if (SpirvOutput.errorWarningMsg.Size() > 0)
				{
					FString ErrorString;
					if (ConvertScBlobToFString(&SpirvOutput.errorWarningMsg, ErrorString))
					{
						Errors.Add(*ErrorString);
					}
				}
				return false;
			}
		}
		return true;
	}

	bool FShaderConductorContext::CompileSpirvToSource(const FShaderConductorOptions& Options, const FShaderConductorTarget& Target, const void* InSpirv, uint32 InSpirvByteSize, FString& OutSource)
	{
		return CompileSpirvToSourceBuffer(
			Options, Target, InSpirv, InSpirvByteSize,
			[&OutSource](const void* Data, uint32 Size)
			{
				// Convert source buffer to FString
				ConvertByteArrayToFString(Data, Size, OutSource);
			}
		);
	}

	bool FShaderConductorContext::CompileSpirvToSourceAnsi(const FShaderConductorOptions& Options, const FShaderConductorTarget& Target, const void* InSpirv, uint32 InSpirvByteSize, TArray<ANSICHAR>& OutSource)
	{
		return CompileSpirvToSourceBuffer(
			Options, Target, InSpirv, InSpirvByteSize,
			[&OutSource](const void* Data, uint32 Size)
			{
				// Convert source buffer to ANSI string
				ConvertByteArrayToAnsiString(reinterpret_cast<const ANSICHAR*>(Data), Size, OutSource);
			}
		);
	}

	bool FShaderConductorContext::CompileSpirvToSourceBuffer(const FShaderConductorOptions& Options, const FShaderConductorTarget& Target, const void* InSpirv, uint32 InSpirvByteSize, const TFunction<void(const void* Data, uint32 Size)>& OutputCallback)
	{
		check(OutputCallback != nullptr);
		check(InSpirv != nullptr);
		check(InSpirvByteSize > 0);
		checkf(InSpirvByteSize % 4 == 0, TEXT("SPIR-V code unaligned. Size must be a multiple of 4, but %u was specified."), InSpirvByteSize);

		// Convert descriptors for ShaderConductor interface
		ShaderConductor::Compiler::SourceDesc ScSourceDesc;
		ConvertScSourceDesc(*Intermediates, ScSourceDesc);

		ShaderConductor::Compiler::TargetDesc ScTargetDesc;
		ConvertScTargetDesc(*Intermediates, Target, ScTargetDesc);

		ShaderConductor::Compiler::Options ScOptions;
		ConvertScOptions(Options, ScOptions, Intermediates->CustomDxcArgRefs, Intermediates->DxcArgRefs);

		ShaderConductor::Compiler::ResultDesc ScBinaryDesc;
		ScBinaryDesc.target.Reset(InSpirv, InSpirvByteSize);
		ScBinaryDesc.isText = false;
		ScBinaryDesc.hasError = false;

		// Convert the input SPIR-V into Metal high level source
		bool bSucceeded = false;
		bool bException = false;
		ShaderConductor::Compiler::ResultDesc ResultDesc;
		ScConvertBinaryWrapper(ScBinaryDesc, ScSourceDesc, ScTargetDesc, ScOptions, ResultDesc, bException);

		if (!ResultDesc.hasError && !bException && ResultDesc.target.Size() > 0)
		{
			// Copy result blob into output SPIR-V module
			OutputCallback(ResultDesc.target.Data(), ResultDesc.target.Size());
			bSucceeded = true;
		}
		else
		{
			if (bException)
			{
				Errors.Add(TEXT("ShaderConductor exception during SPIR-V binary conversion"));
			}
			bSucceeded = false;
		}

		// Append compile error and warning to output reports
		if (ResultDesc.errorWarningMsg.Size() > 0)
		{
			FString ErrorString;
			if (ConvertScBlobToFString(&ResultDesc.errorWarningMsg, ErrorString))
			{
				Errors.Add(*ErrorString);
			}
		}

		return bSucceeded;
	}

	void FShaderConductorContext::FlushErrors(TArray<FShaderCompilerError>& OutErrors)
	{
		if (OutErrors.Num() > 0)
		{
			// Append internal list of errors to output list, then clear internal list
			for (const FShaderCompilerError& ErrorEntry : Errors)
			{
				OutErrors.Add(ErrorEntry);
			}
			Errors.Empty();
		}
		else
		{
			// Move internal list of errors into output list
			OutErrors = MoveTemp(Errors);
		}
	}

	const ANSICHAR* FShaderConductorContext::GetSourceString() const
	{
		return (Intermediates->ShaderSource.Num() > 0 ? Intermediates->ShaderSource.GetData() : nullptr);
	}

	int32 FShaderConductorContext::GetSourceLength() const
	{
		return (Intermediates->ShaderSource.Num() > 0 ? (Intermediates->ShaderSource.Num() - 1) : 0);
	}

	void FShaderConductorContext::ConvertCompileErrors(TArray<FString>&& ErrorStringLines, TArray<FShaderCompilerError>& OutErrors)
	{
		// Returns whether the specified line in the 'ErrorStringLines' array has a line marker.
		auto HasErrorLineMarker = [&ErrorStringLines](int32 LineIndex)
		{
			if (LineIndex + 2 < ErrorStringLines.Num())
			{
				return IsTextLineDxcLineMarker(ErrorStringLines[LineIndex + 2]);
			}
			return false;
		};

		// Iterate over all errors. Most (but not all) contain a highlighted line and line marker.
		for (int32 LineIndex = 0; LineIndex < ErrorStringLines.Num();)
		{
			if (HasErrorLineMarker(LineIndex))
			{
				// Add current line as error with highlighted source line (LineIndex+1) and line marker (LineIndex+2)
				OutErrors.Emplace(MoveTemp(ErrorStringLines[LineIndex]), MoveTemp(ErrorStringLines[LineIndex + 1]), MoveTemp(ErrorStringLines[LineIndex + 2]));
				LineIndex += 3;
			}
			else
			{
				// Add current line as single error
				OutErrors.Emplace(MoveTemp(ErrorStringLines[LineIndex]));
				LineIndex += 1;
			}
		}
	}

	bool FShaderConductorContext::Disassemble(EShaderConductorIR Language, const void* Binary, uint32 BinaryByteSize, TArray<ANSICHAR>& OutAssemblyText)
	{
		// Initialize Blob with input SPIR-V code
		ShaderConductor::Compiler::DisassembleDesc BinaryDesc;
		switch (Language)
		{
		case EShaderConductorIR::Spirv:
			BinaryDesc.language = ShaderConductor::ShadingLanguage::SpirV;
			break;
		case EShaderConductorIR::Dxil:
			BinaryDesc.language = ShaderConductor::ShadingLanguage::Dxil;
			break;
		}
		BinaryDesc.binary = reinterpret_cast<const uint8_t*>(Binary);
		BinaryDesc.binarySize = BinaryByteSize;

		// Disassemble via ShaderConductor interface
		ShaderConductor::Compiler::ResultDesc TextOutput = ShaderConductor::Compiler::Disassemble(BinaryDesc);
		if (TextOutput.isText && !TextOutput.hasError)
		{
			// Convert and return output to ANSI string
			ConvertByteArrayToAnsiString(reinterpret_cast<const ANSICHAR*>(TextOutput.target.Data()), TextOutput.target.Size(), OutAssemblyText);
			return true;
		}

		return false;
	}

#else // PLATFORM_MAC || PLATFORM_WINDOWS || PLATFORM_LINUX

	FShaderConductorContext::FShaderConductorContext()
	{
		checkf(0, TEXT("Cannot instantiate FShaderConductorContext for unsupported platform"));
	}

	FShaderConductorContext::~FShaderConductorContext()
	{
		// Dummy
	}

	FShaderConductorContext::FShaderConductorContext(FShaderConductorContext&& Rhs)
	{
		// Dummy
	}

	FShaderConductorContext& FShaderConductorContext::operator = (FShaderConductorContext&& Rhs)
	{
		return *this; // Dummy
	}

	bool FShaderConductorContext::LoadSource(const FString& ShaderSource, const FString& Filename, const FString& EntryPoint, EShaderFrequency ShaderStage, const FShaderCompilerDefinitions* Definitions, const TArray<FString>* ExtraDxcArgs)
	{
		return false; // Dummy
	}

	bool FShaderConductorContext::LoadSource(const ANSICHAR* ShaderSource, const ANSICHAR* Filename, const ANSICHAR* EntryPoint, EShaderFrequency ShaderStage, const FShaderCompilerDefinitions* Definitions, const TArray<FString>* ExtraDxcArgs)
	{
		return false; // Dummy
	}

	bool FShaderConductorContext::RewriteHlsl(const FShaderConductorOptions& Options, FString* OutSource)
	{
		return false; // Dummy
	}

	bool FShaderConductorContext::CompileHlslToSpirv(const FShaderConductorOptions& Options, TArray<uint32>& OutSpirv)
	{
		return false; // Dummy
	}

	bool FShaderConductorContext::CompileSpirvToSource(const FShaderConductorOptions& Options, const FShaderConductorTarget& Target, const void* InSpirv, uint32 InSpirvByteSize, FString& OutSource)
	{
		return false; // Dummy
	}

	bool FShaderConductorContext::CompileSpirvToSourceAnsi(const FShaderConductorOptions& Options, const FShaderConductorTarget& Target, const void* InSpirv, uint32 InSpirvByteSize, TArray<ANSICHAR>& OutSource)
	{
		return false; // Dummy
	}

	bool FShaderConductorContext::CompileSpirvToSourceBuffer(const FShaderConductorOptions& Options, const FShaderConductorTarget& Target, const void* InSpirv, uint32 InSpirvByteSize, const TFunction<void(const void* Data, uint32 Size)>& OutputCallback)
	{
		return false; // Dummy
	}

	void FShaderConductorContext::FlushErrors(TArray<FShaderCompilerError>& OutErrors)
	{
		// Dummy
	}

	const ANSICHAR* FShaderConductorContext::GetSourceString() const
	{
		return nullptr; // Dummy
	}

	int32 FShaderConductorContext::GetSourceLength() const
	{
		return 0; // Dummy
	}

	void FShaderConductorContext::ConvertCompileErrors(const TArray<FString>& ErrorStringLines, TArray<FShaderCompilerError>& OutErrors)
	{
		// Dummy
	}

	bool FShaderConductorContext::Disassemble(EShaderConductorIR Language, const void* Binary, uint32 BinaryByteSize, TArray<ANSICHAR>& OutAssemblyText)
	{
		return false; // Dummy
	}

#endif // PLATFORM_MAC || PLATFORM_WINDOWS || PLATFORM_LINUX

	bool FShaderConductorContext::IsIntermediateSpirvOutputVariable(const ANSICHAR* SpirvVariableName)
	{
		// This is only true for "temp.var.hullMainRetVal" which is generated by DXC as intermediate output variable to communicate patch constant data in a Hull Shader.
		return (SpirvVariableName != nullptr && FCStringAnsi::Strcmp(SpirvVariableName, FShaderConductorContext::GetIdentifierTable().IntermediateTessControlOutput) == 0);
	}

	const FShaderConductorIdentifierTable& FShaderConductorContext::GetIdentifierTable()
	{
		static const FShaderConductorIdentifierTable IdentifierTable
		{
			/*InputAttribute:*/					"in.var.ATTRIBUTE",
			/*GlobalsUniformBuffer:*/			"$Globals",
			/*IntermediateTessControlOutput:*/	"temp.var.hullMainRetVal",
			/*DummySampler:*/					"SPIRV_Cross_DummySampler",
		};
		return IdentifierTable;
	}

	static const TCHAR* GetGlslShaderFileExt(EShaderFrequency ShaderStage)
	{
		switch (ShaderStage)
		{
		case SF_Vertex:			return TEXT("vert");
		case SF_Mesh:			return TEXT("mesh");
		case SF_Amplification:	return TEXT("task");
		case SF_Pixel:			return TEXT("frag");
		case SF_Geometry:		return TEXT("geom");
		case SF_Compute:		return TEXT("comp");
		case SF_RayGen:			return TEXT("rgen");
		case SF_RayMiss:		return TEXT("rmiss");
		case SF_RayHitGroup:	return TEXT("rahit"); // rahit/rchit
		case SF_RayCallable:	return TEXT("rcall");
		default:				return TEXT("glsl");
		}
	}

	const TCHAR* FShaderConductorContext::GetShaderFileExt(EShaderConductorLanguage Language, EShaderFrequency ShaderStage)
	{
		switch (Language)
		{
		case EShaderConductorLanguage::Hlsl:		return TEXT("hlsl");
		case EShaderConductorLanguage::Glsl:		[[fallthrough]];
		case EShaderConductorLanguage::Essl:		return GetGlslShaderFileExt(ShaderStage);
		case EShaderConductorLanguage::Metal_macOS: [[fallthrough]];
		case EShaderConductorLanguage::Metal_iOS:	return TEXT("metal");
		default:									return TEXT("");
		}
	}

	void FShaderConductorContext::Shutdown()
	{
#if PLATFORM_LINUX
		ShaderConductor::Compiler::Shutdown();
#endif
	}

} // namespace CrossCompiler