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Copyright (c) 2017 Intel Corporation

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======================= end_copyright_notice ==================================*/

#include "Compiler/Optimizer/OpenCLPasses/PrivateMemory/PrivateMemoryUsageAnalysis.hpp"

#include "AdaptorCommon/ImplicitArgs.hpp"
#include "Compiler/IGCPassSupport.h"

using namespace llvm;
using namespace IGC;

// Register pass to igc-opt
#define PASS_FLAG "igc-private-mem-usage-analysis"
#define PASS_DESCRIPTION "Analyzes the presence of private memory allocation"
#define PASS_CFG_ONLY false
#define PASS_ANALYSIS false
IGC_INITIALIZE_PASS_BEGIN(PrivateMemoryUsageAnalysis, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
IGC_INITIALIZE_PASS_DEPENDENCY(MetaDataUtilsWrapper)
IGC_INITIALIZE_PASS_DEPENDENCY(CodeGenContextWrapper)
IGC_INITIALIZE_PASS_END(PrivateMemoryUsageAnalysis, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)

char PrivateMemoryUsageAnalysis::ID = 0;

PrivateMemoryUsageAnalysis::PrivateMemoryUsageAnalysis()
  : ModulePass(ID), m_hasPrivateMem(false)
{
    initializePrivateMemoryUsageAnalysisPass(*PassRegistry::getPassRegistry());
}

bool PrivateMemoryUsageAnalysis::runOnModule(Module &M)
{
    bool changed = false;
    IGCMD::MetaDataUtils *pMdUtils = getAnalysis<MetaDataUtilsWrapper>().getMetaDataUtils();

    // Run on all functions defined in this module
    for( Module::iterator I = M.begin(), E = M.end(); I != E; ++I )
    {
        Function* pFunc = &(*I);
        if( pFunc->isDeclaration() )
            continue;
        if (pMdUtils->findFunctionsInfoItem(pFunc) == pMdUtils->end_FunctionsInfo())
            continue;
        if( runOnFunction(*pFunc) )
        {
            changed = true;
        }
    }

    return changed;
}

bool PrivateMemoryUsageAnalysis::runOnFunction(Function &F)
{
    // Processing new function
    m_hasPrivateMem = false;
    
     visit(F);

     // Struct types always use private memory unless regtomem can 
     // promote them.  Check the function signature to see if any 
     // structs are passesed as arguments.
     if( !m_hasPrivateMem )
     {
         Function::arg_iterator argument = F.arg_begin();
         for( ; argument != F.arg_end(); ++argument )
         {
             Argument* arg = &(*argument);

             if( arg->getType()->isPointerTy() )
             {
                 Type* type = arg->getType()->getPointerElementType();

                 if( StructType *structType = dyn_cast<StructType>(type) )
                 {
                     if( !structType->isOpaque() )
                     {
                         m_hasPrivateMem = true;
                     }
                 }
             }
         }
     }
    //Add private memory implicit arg
    SmallVector<ImplicitArg::ArgType, ImplicitArg::NUM_IMPLICIT_ARGS> implicitArgs;
    implicitArgs.push_back(ImplicitArg::R0);
    if (F.hasFnAttribute("visaStackCall"))
    {
        m_hasPrivateMem = true;
    }

    // For double emulation, need to add private base (conservative).
    if (!m_hasPrivateMem)
    {
        CodeGenContext* pCtx = getAnalysis<CodeGenContextWrapper>().getCodeGenContext();

        // This is the condition that double emulation is used.
        if ((IGC_IS_FLAG_ENABLED(ForceDPEmulation) ||
             (pCtx->m_DriverInfo.NeedFP64() && !pCtx->platform.supportFP64())))
        {
            m_hasPrivateMem = true;
        }
    }
        
    if (m_hasPrivateMem)
    {
        implicitArgs.push_back(ImplicitArg::PRIVATE_BASE);
    }
    ImplicitArgs::addImplicitArgs(F, implicitArgs, getAnalysis<MetaDataUtilsWrapper>().getMetaDataUtils());
    
    return true;
}

void PrivateMemoryUsageAnalysis::visitAllocaInst(llvm::AllocaInst &AI)
{
    assert (AI.getType()->getAddressSpace() == ADDRESS_SPACE_PRIVATE && "Allocaitons are expected to be in private address space");

    // If we encountered Alloca, then the function uses private memory
    m_hasPrivateMem = true;
}
