/*===================== begin_copyright_notice ==================================

Copyright (c) 2017 Intel Corporation

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
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The above copyright notice and this permission notice shall be included
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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======================= end_copyright_notice ==================================*/
#pragma once
#include "Compiler/CISACodeGen/helper.h"
#include "Compiler/CISACodeGen/TranslationTable.hpp"
#include "Compiler/CISACodeGen/ShaderCodeGen.hpp"
#include "Compiler/CISACodeGen/WIAnalysis.hpp"
#include "Compiler/MetaDataUtilsWrapper.h"
#include "Compiler/MetaDataApi/MetaDataApi.h"

#include "common/LLVMWarningsPush.hpp"
#include <llvm/IR/PassManager.h>
#include <llvm/IR/IRBuilder.h>
#include <llvm/ADT/SmallBitVector.h>
#include "common/LLVMWarningsPop.hpp"
#include "common/IGCIRBuilder.h"

#include <map>

/// @brief ConstantCoalescing merges multiple constant loads into one load
/// of larger quantity
/// - change to oword loads if the address is uniform
/// - change to gather4 or sampler loads if the address is not uniform

using namespace llvm;

namespace IGC
{

struct BufChunk
{
    llvm::Value*       bufIdxV;     // buffer index when it is indirect
    llvm::Value*       baseIdxV;    // base-address index when it is indirect
    uint         addrSpace;         // resource address space when it is direct
    uint         elementSize;       // size in bytes of the basic data element
    uint         chunkStart;        // offset of the first data element in chunk in units of elementSize
    uint         chunkSize;         // chunk size in elements
    llvm::Instruction* chunkIO;     // coalesced load
};

class ConstantCoalescing : public llvm::FunctionPass
{
public:
    static char ID;
    ConstantCoalescing();

    virtual void getAnalysisUsage(llvm::AnalysisUsage &AU) const override
    {
        AU.setPreservesCFG();
        AU.addPreservedID(WIAnalysis::ID);
        AU.addRequired<DominatorTreeWrapperPass>();
        AU.addRequired<WIAnalysis>();
        AU.addRequired<MetaDataUtilsWrapper>();
        AU.addRequired<CodeGenContextWrapper>();
        AU.addRequired<TranslationTable>();
        AU.addPreservedID(TranslationTable::ID);

    }

    void ProcessBlock(llvm::BasicBlock* blk,
                     std::vector<BufChunk*> &dircb_owlds,
                     std::vector<BufChunk*> &indcb_owlds,
                     std::vector<BufChunk*> &indcb_gathers );
    void ProcessFunction(llvm::Function* function);

    virtual bool runOnFunction(llvm::Function &func) override;
private:

    class IRBuilderWrapper : protected llvm::IGCIRBuilder<>
    {

    public:
        IRBuilderWrapper(LLVMContext &C, TranslationTable* pTT) : llvm::IGCIRBuilder<>(C), m_TT(pTT)
        {

        }

        /// \brief Get a constant 32-bit value.
        ConstantInt *getInt32(uint32_t C) {
            return IGCIRBuilder<>::getInt32(C);
        }

        using IGCIRBuilder<>::getCurrentDebugLocation;
        using IGCIRBuilder<>::getInt32Ty;
        using IGCIRBuilder<>::getFloatTy;
        using IGCIRBuilder<>::SetInsertPoint;

        //Instruction creators:

        Value *CreateAdd(Value *LHS, Value *RHS, const Twine &Name = "",
            bool HasNUW = false, bool HasNSW = false) {
            Value * val = IGCIRBuilder<>::CreateAdd(LHS, RHS, Name, HasNUW, HasNSW);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateAnd(Value *LHS, Value *RHS, const Twine &Name = "") {
            Value * val = IRBuilder<>::CreateAnd(LHS, RHS, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreatePtrToInt(Value *V, Type *DestTy,
            const Twine &Name = "") {
            Value* val = IGCIRBuilder<>::CreatePtrToInt(V, DestTy, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        LoadInst *CreateLoad(Value *Ptr, const char *Name) {
            LoadInst* val = IGCIRBuilder<>::CreateLoad(Ptr, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }
        LoadInst *CreateLoad(Value *Ptr, const Twine &Name = "") {
            LoadInst* val = IGCIRBuilder<>::CreateLoad(Ptr, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }
        LoadInst *CreateLoad(Value *Ptr, bool isVolatile, const Twine &Name = "") {
            LoadInst* val = IGCIRBuilder<>::CreateLoad(Ptr, isVolatile, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        CallInst *CreateCall2(Value *Callee, Value *Arg1, Value *Arg2,
            const Twine &Name = "") {
            CallInst *val = IGCIRBuilder<>::CreateCall2(Callee, Arg1, Arg2, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateMul(Value *LHS, Value *RHS, const Twine &Name = "",
            bool HasNUW = false, bool HasNSW = false) {
            Value *val = IGCIRBuilder<>::CreateMul(LHS, RHS, Name, HasNUW, HasNSW);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateShl(Value *LHS, Value *RHS, const Twine &Name = "",
            bool HasNUW = false, bool HasNSW = false) {
            Value *val = IGCIRBuilder<>::CreateShl(LHS, RHS, Name, HasNUW, HasNSW);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateLShr(Value *LHS, Value *RHS, const Twine &Name = "",
            bool isExact = false) {
            Value *val = IGCIRBuilder<>::CreateLShr(LHS, RHS, Name, isExact);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateBitCast(Value *V, Type *DestTy,
            const Twine &Name = "") {
            Value *val = IGCIRBuilder<>::CreateBitCast(V, DestTy, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateZExt(Value *V, Type *DestTy, const Twine &Name = "") {
            Value *val = IRBuilder<>::CreateZExt(V, DestTy, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateZExtOrTrunc(Value *V, Type *DestTy, const Twine &Name = "") {
            Value *val = IRBuilder<>::CreateZExtOrTrunc(V, DestTy, Name);
            if (val != V)
            {
                m_TT->RegisterNewValueAndAssignID(val);
            }
            return val;
        }


        Value *CreateExtractElement(Value *Vec, Value *Idx,
            const Twine &Name = "") {
            Value *val = IGCIRBuilder<>::CreateExtractElement(Vec, Idx, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        CallInst *CreateCall(Value *Callee, ArrayRef<Value *> Args,
            const Twine &Name = "") {
            CallInst *val = IGCIRBuilder<>::CreateCall(Callee, Args, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

        Value *CreateInsertElement(Value *Vec, Value *NewElt, Value *Idx,
            const Twine &Name = "") {
            Value *val = IGCIRBuilder<>::CreateInsertElement(Vec, NewElt, Idx, Name);
            m_TT->RegisterNewValueAndAssignID(val);
            return val;
        }

    private:
        TranslationTable* m_TT;
    };

    CodeGenContext* m_ctx;
    llvm::Function* curFunc;
    // agent to modify the llvm-ir
    IRBuilderWrapper *irBuilder;
    // maintain the uniformness info
    WIAnalysis *wiAns;
    const llvm::DataLayout *dataLayout;
    TranslationTable *m_TT;


    /// check if two access have the same buffer-base
    bool   CompareBufferBase(llvm::Value *bufIdxV1, uint bufid1, llvm::Value *bufIdxV2, uint bufid2);
    /// find element base and element imm-offset
    llvm::Value* SimpleBaseOffset(llvm::Value *elt_idxv, uint& offset);
    /// used along ocl path, based upon int2ptr
    bool   DecomposePtrExp(llvm::Value *ptr_val, llvm::Value*& buf_idxv, llvm::Value*& elt_idxv, uint& eltid);
    uint   CheckVectorElementUses(llvm::Instruction *load);
    void   AdjustChunk(BufChunk *cov_chunk, uint start_adj, uint size_adj);
    void   EnlargeChunk(BufChunk *cov_chunk, uint size_adj);
    void   MoveExtracts(BufChunk *cov_chunk, llvm::Instruction *load, uint start_adj);
    llvm::Value* FormChunkAddress(BufChunk *chunk);
    void   CombineTwoLoads(BufChunk *cov_chunk, llvm::Instruction *load, uint eltid, uint numelt);
    llvm::Instruction *CreateChunkLoad(llvm::Instruction *load, BufChunk *chunk, uint eltid, uint alignment);
    llvm::Instruction *AddChunkExtract(llvm::Instruction *load, uint offset);
    llvm::Instruction *FindOrAddChunkExtract(BufChunk *cov_chunk, uint eltid);
    llvm::Instruction *EnlargeChunkAddExtract(BufChunk *cov_chunk, uint size_adj, uint eltid);
    llvm::Instruction *AdjustChunkAddExtract(BufChunk *cov_chunk, uint start_adj, uint size_adj, uint eltid);
    llvm::Instruction *CreateSamplerLoad(llvm::Value* index, uint addrSpace);
    void MergeUniformLoad(llvm::Instruction *load,
        llvm::Value *bufIdxV, uint addrSpace,
        llvm::Value *eltIdxV, uint offsetInBytes,
        uint maxEltPlus,
        std::vector<BufChunk*> &chunk_vec);
    void MergeScatterLoad(llvm::Instruction *load,
        llvm::Value *bufIdxV, uint bufid,
        llvm::Value *eltIdxV, uint offsetInBytes,
        uint maxEltPlus,
        std::vector<BufChunk*> &chunk_vec);
    void ScatterToSampler(llvm::Instruction *load,
        llvm::Value *bufIdxV, uint bufid,
        llvm::Value *eltIdxV, uint eltid,
        std::vector<BufChunk*> &chunk_vec);
    /// change IntToPtr to oword-ptr for oword-aligned load in order to avoid SHL
    void ChangePTRtoOWordBased(BufChunk *chunk);

    bool CleanupExtract(llvm::BasicBlock* bb);
    void VectorizePrep(llvm::BasicBlock* bb);
    bool safeToMoveInstUp(Instruction* inst, Instruction* newLocation);

    bool   IsSamplerAlignedAddress(Value* addr) const;
    Value* GetSamplerAlignedAddress(Value* inst);

    uint GetAlignment(Instruction* load) const;
    void SetAlignment(Instruction* load, uint alignment);
};

}
