// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// 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.

#ifndef rr_Nucleus_hpp
#define rr_Nucleus_hpp

#include <atomic>
#include <cassert>
#include <cstdarg>
#include <cstdint>
#include <memory>
#include <vector>

#ifdef None
#undef None  // TODO(b/127920555)
#endif

static_assert(sizeof(short) == 2, "Reactor's 'Short' type is 16-bit, and requires the C++ 'short' to match that.");
static_assert(sizeof(int) == 4, "Reactor's 'Int' type is 32-bit, and requires the C++ 'int' to match that.");

namespace rr
{
	class Type;
	class Value;
	class SwitchCases;
	class BasicBlock;
	class Routine;

	// Optimization holds the optimization settings for code generation.
	class Optimization
	{
	public:
		enum class Level
		{
			None,
			Less,
			Default,
			Aggressive,
		};

		enum class Pass
		{
			Disabled,
			InstructionCombining,
			CFGSimplification,
			LICM,
			AggressiveDCE,
			GVN,
			Reassociate,
			DeadStoreElimination,
			SCCP,
			ScalarReplAggregates,
			EarlyCSEPass,

			Count,
		};

		using Passes = std::vector<Pass>;

		Optimization(Level level = Level::Default, const Passes& passes = {})
			: level(level), passes(passes)
		{
			#if defined(REACTOR_DEFAULT_OPT_LEVEL)
			{
				this->level = Level::REACTOR_DEFAULT_OPT_LEVEL;
			}
			#endif
		}

		Level getLevel() const { return level; }
		const Passes & getPasses() const { return passes; }

	private:
		Level level = Level::Default;
		Passes passes;
	};

	// Config holds the Reactor configuration settings.
	class Config
	{
	public:
		// Edit holds a number of modifications to a config, that can be applied
		// on an existing Config to produce a new Config with the specified
		// changes.
		class Edit
		{
		public:
			static const Edit None;

			Edit & set(Optimization::Level level) { optLevel = level; optLevelChanged = true; return *this; }
			Edit & add(Optimization::Pass pass) { optPassEdits.push_back({ListEdit::Add, pass}); return *this; }
			Edit & remove(Optimization::Pass pass) { optPassEdits.push_back({ListEdit::Remove, pass}); return *this; }
			Edit & clearOptimizationPasses() { optPassEdits.push_back({ListEdit::Clear, Optimization::Pass::Disabled}); return *this; }

			Config apply(const Config &cfg) const;

		private:
			enum class ListEdit { Add, Remove, Clear };
			using OptPassesEdit = std::pair<ListEdit, Optimization::Pass>;

			template <typename T>
			void apply(const std::vector<std::pair<ListEdit, T>> & edits, std::vector<T>& list) const;

			Optimization::Level optLevel;
			bool optLevelChanged = false;
			std::vector<OptPassesEdit> optPassEdits;
		};

		Config() = default;
		Config(const Optimization & optimization) : optimization(optimization) {}

		const Optimization & getOptimization() const { return optimization; }

	private:
		Optimization optimization;
	};

	class Nucleus
	{
	public:
		Nucleus();

		virtual ~Nucleus();

		// Default configuration to use when no other configuration is specified.
		// The new configuration will be applied to subsequent reactor calls.
		static void setDefaultConfig(const Config &cfg);
		static void adjustDefaultConfig(const Config::Edit &cfgEdit);
		static Config getDefaultConfig();

		std::shared_ptr<Routine> acquireRoutine(const char *name, const Config::Edit &cfgEdit = Config::Edit::None);

		static Value *allocateStackVariable(Type *type, int arraySize = 0);
		static BasicBlock *createBasicBlock();
		static BasicBlock *getInsertBlock();
		static void setInsertBlock(BasicBlock *basicBlock);

		static void createFunction(Type *ReturnType, std::vector<Type*> &Params);
		static Value *getArgument(unsigned int index);

		// Coroutines
		using CoroutineHandle = void*;

		template <typename... ARGS>
		using CoroutineBegin = CoroutineHandle(ARGS...);
		using CoroutineAwait = bool(CoroutineHandle, void* yieldValue);
		using CoroutineDestroy = void(CoroutineHandle);

		enum CoroutineEntries
		{
			CoroutineEntryBegin = 0,
			CoroutineEntryAwait,
			CoroutineEntryDestroy,
			CoroutineEntryCount
		};

		static void createCoroutine(Type *ReturnType, std::vector<Type*> &Params);
		std::shared_ptr<Routine> acquireCoroutine(const char *name, const Config::Edit &cfg = Config::Edit::None);
		static void yield(Value*);

		// Terminators
		static void createRetVoid();
		static void createRet(Value *V);
		static void createBr(BasicBlock *dest);
		static void createCondBr(Value *cond, BasicBlock *ifTrue, BasicBlock *ifFalse);

		// Binary operators
		static Value *createAdd(Value *lhs, Value *rhs);
		static Value *createSub(Value *lhs, Value *rhs);
		static Value *createMul(Value *lhs, Value *rhs);
		static Value *createUDiv(Value *lhs, Value *rhs);
		static Value *createSDiv(Value *lhs, Value *rhs);
		static Value *createFAdd(Value *lhs, Value *rhs);
		static Value *createFSub(Value *lhs, Value *rhs);
		static Value *createFMul(Value *lhs, Value *rhs);
		static Value *createFDiv(Value *lhs, Value *rhs);
		static Value *createURem(Value *lhs, Value *rhs);
		static Value *createSRem(Value *lhs, Value *rhs);
		static Value *createFRem(Value *lhs, Value *rhs);
		static Value *createShl(Value *lhs, Value *rhs);
		static Value *createLShr(Value *lhs, Value *rhs);
		static Value *createAShr(Value *lhs, Value *rhs);
		static Value *createAnd(Value *lhs, Value *rhs);
		static Value *createOr(Value *lhs, Value *rhs);
		static Value *createXor(Value *lhs, Value *rhs);

		// Unary operators
		static Value *createNeg(Value *V);
		static Value *createFNeg(Value *V);
		static Value *createNot(Value *V);

		// Memory instructions
		static Value *createLoad(Value *ptr, Type *type, bool isVolatile = false, unsigned int alignment = 0, bool atomic = false , std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createStore(Value *value, Value *ptr, Type *type, bool isVolatile = false, unsigned int aligment = 0, bool atomic = false, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createGEP(Value *ptr, Type *type, Value *index, bool unsignedIndex);

		// Masked Load / Store instructions
		static Value *createMaskedLoad(Value *base, Type *elementType, Value *mask, unsigned int alignment, bool zeroMaskedLanes);
		static void createMaskedStore(Value *base, Value *value, Value *mask, unsigned int alignment);

		// Barrier instructions
		static void createFence(std::memory_order memoryOrder);

		// Atomic instructions
		static Value *createAtomicAdd(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicSub(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicAnd(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicOr(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicXor(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicMin(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicMax(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicUMin(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicUMax(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicExchange(Value *ptr, Value *value, std::memory_order memoryOrder = std::memory_order_relaxed);
		static Value *createAtomicCompareExchange(Value *ptr, Value *value, Value *compare, std::memory_order memoryOrderEqual, std::memory_order memoryOrderUnequal);

		// Cast/Conversion Operators
		static Value *createTrunc(Value *V, Type *destType);
		static Value *createZExt(Value *V, Type *destType);
		static Value *createSExt(Value *V, Type *destType);
		static Value *createFPToUI(Value *V, Type *destType);
		static Value *createFPToSI(Value *V, Type *destType);
		static Value *createSIToFP(Value *V, Type *destType);
		static Value *createFPTrunc(Value *V, Type *destType);
		static Value *createFPExt(Value *V, Type *destType);
		static Value *createBitCast(Value *V, Type *destType);

		// Compare instructions
		static Value *createPtrEQ(Value *lhs, Value *rhs);
		static Value *createICmpEQ(Value *lhs, Value *rhs);
		static Value *createICmpNE(Value *lhs, Value *rhs);
		static Value *createICmpUGT(Value *lhs, Value *rhs);
		static Value *createICmpUGE(Value *lhs, Value *rhs);
		static Value *createICmpULT(Value *lhs, Value *rhs);
		static Value *createICmpULE(Value *lhs, Value *rhs);
		static Value *createICmpSGT(Value *lhs, Value *rhs);
		static Value *createICmpSGE(Value *lhs, Value *rhs);
		static Value *createICmpSLT(Value *lhs, Value *rhs);
		static Value *createICmpSLE(Value *lhs, Value *rhs);
		static Value *createFCmpOEQ(Value *lhs, Value *rhs);
		static Value *createFCmpOGT(Value *lhs, Value *rhs);
		static Value *createFCmpOGE(Value *lhs, Value *rhs);
		static Value *createFCmpOLT(Value *lhs, Value *rhs);
		static Value *createFCmpOLE(Value *lhs, Value *rhs);
		static Value *createFCmpONE(Value *lhs, Value *rhs);
		static Value *createFCmpORD(Value *lhs, Value *rhs);
		static Value *createFCmpUNO(Value *lhs, Value *rhs);
		static Value *createFCmpUEQ(Value *lhs, Value *rhs);
		static Value *createFCmpUGT(Value *lhs, Value *rhs);
		static Value *createFCmpUGE(Value *lhs, Value *rhs);
		static Value *createFCmpULT(Value *lhs, Value *rhs);
		static Value *createFCmpULE(Value *lhs, Value *rhs);
		static Value *createFCmpUNE(Value *lhs, Value *rhs);

		// Vector instructions
		static Value *createExtractElement(Value *vector, Type *type, int index);
		static Value *createInsertElement(Value *vector, Value *element, int index);
		static Value *createShuffleVector(Value *V1, Value *V2, const int *select);

		// Other instructions
		static Value *createSelect(Value *C, Value *ifTrue, Value *ifFalse);
		static SwitchCases *createSwitch(Value *control, BasicBlock *defaultBranch, unsigned numCases);
		static void addSwitchCase(SwitchCases *switchCases, int label, BasicBlock *branch);
		static void createUnreachable();

		// Constant values
		static Value *createNullValue(Type *type);
		static Value *createConstantLong(int64_t i);
		static Value *createConstantInt(int i);
		static Value *createConstantInt(unsigned int i);
		static Value *createConstantBool(bool b);
		static Value *createConstantByte(signed char i);
		static Value *createConstantByte(unsigned char i);
		static Value *createConstantShort(short i);
		static Value *createConstantShort(unsigned short i);
		static Value *createConstantFloat(float x);
		static Value *createNullPointer(Type *type);
		static Value *createConstantVector(const int64_t *constants, Type *type);
		static Value *createConstantVector(const double *constants, Type *type);

		static Type *getPointerType(Type *elementType);
	};
}

#endif   // rr_Nucleus_hpp