mpl2mpl/src/clone.cpp

/*
 * Copyright (c) 2023 Huawei Device Co., Ltd.
 * 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.
 */

#include "clone.h"
#include <iostream>
#include <algorithm>
#include "mir_symbol.h"

// For some funcs, when we can ignore their return-values, we clone a new func of
// them without return-values. We configure a list to save these funcs and clone
// at the very beginning so that clones can also enjoy the optimizations after.
// This mainly contains the clone of funcbody(include labels, symbols, arguments,
// etc.) and the update of the new func infomation.
namespace maple {
ReplaceRetIgnored::ReplaceRetIgnored(MemPool *memPool)
    : memPool(memPool), allocator(memPool), toBeClonedFuncNames(allocator.Adapter())
{
}

bool ReplaceRetIgnored::RealShouldReplaceWithVoidFunc(Opcode op, size_t nRetSize, const MIRFunction &calleeFunc) const
{
    MIRType *returnType = GlobalTables::GetTypeTable().GetTypeFromTyIdx(calleeFunc.GetReturnTyIdx());
    return nRetSize == 0 &&
           (op == OP_virtualcallassigned || op == OP_callassigned || op == OP_superclasscallassigned) &&
           !calleeFunc.IsNative() && (returnType->GetKind() == kTypePointer) && (returnType->GetPrimType() == PTY_ref);
}

bool ReplaceRetIgnored::ShouldReplaceWithVoidFunc(const CallMeStmt &stmt, const MIRFunction &calleeFunc) const
{
    return RealShouldReplaceWithVoidFunc(stmt.GetOp(), stmt.MustDefListSize(), calleeFunc);
}

std::string ReplaceRetIgnored::GenerateNewBaseName(const MIRFunction &originalFunc) const
{
    return std::string(originalFunc.GetBaseFuncName()).append(kVoidRetSuffix);
}

std::string ReplaceRetIgnored::GenerateNewFullName(const MIRFunction &originalFunc) const
{
    const std::string &oldSignature = originalFunc.GetSignature();
    auto retPos = oldSignature.find("_29");
    constexpr auto retPosIndex = 3;
    return std::string(originalFunc.GetBaseClassName())
        .append(namemangler::kNameSplitterStr)
        .append(GenerateNewBaseName(originalFunc))
        .append(namemangler::kNameSplitterStr)
        .append(oldSignature.substr(0, retPos + retPosIndex))
        .append("V");
}

MIRSymbol *Clone::CloneLocalSymbol(const MIRSymbol &oldSym, const MIRFunction &newFunc)
{
    MemPool *newMP = newFunc.GetDataMemPool();
    MIRSymbol *newSym = newMP->New<MIRSymbol>(oldSym);
    if (oldSym.GetSKind() == kStConst) {
        newSym->SetKonst(oldSym.GetKonst()->Clone(*newMP));
    } else if (oldSym.GetSKind() == kStPreg) {
        newSym->SetPreg(newMP->New<MIRPreg>(*oldSym.GetPreg()));
    } else if (oldSym.GetSKind() == kStFunc) {
        CHECK_FATAL(false, "%s has unexpected local func symbol", oldSym.GetName().c_str());
    }
    return newSym;
}

void Clone::CloneSymbols(MIRFunction &newFunc, const MIRFunction &oldFunc)
{
    size_t symTabSize = oldFunc.GetSymbolTabSize();
    for (size_t i = oldFunc.GetFormalCount() + 1; i < symTabSize; ++i) {
        MIRSymbol *sym = oldFunc.GetSymbolTabItem(static_cast<uint32>(i));
        if (sym == nullptr) {
            continue;
        }
        MIRSymbol *newSym = CloneLocalSymbol(*sym, newFunc);
        if (!newFunc.GetSymTab()->AddStOutside(newSym)) {
            CHECK_FATAL(false, "%s already existed in func %s", sym->GetName().c_str(), newFunc.GetName().c_str());
        }
    }
}

void Clone::CloneLabels(MIRFunction &newFunc, const MIRFunction &oldFunc)
{
    size_t labelTabSize = oldFunc.GetLabelTab()->GetLabelTableSize();
    for (size_t i = 1; i < labelTabSize; ++i) {
        const std::string &labelName = oldFunc.GetLabelTabItem(static_cast<uint32>(i));
        GStrIdx strIdx = GlobalTables::GetStrTable().GetOrCreateStrIdxFromName(labelName);
        (void)newFunc.GetLabelTab()->AddLabel(strIdx);
    }
}

// Clone a function
MIRFunction *Clone::CloneFunction(MIRFunction &originalFunction, const std::string &newBaseFuncName,
                                  MIRType *returnType) const
{
    MapleAllocator cgAlloc(originalFunction.GetCodeMempool());
    ArgVector argument(cgAlloc.Adapter());
    CloneArgument(originalFunction, argument);
    MIRType *retType = returnType;
    if (retType == nullptr) {
        retType = originalFunction.GetReturnType();
    }
    std::string fullName = originalFunction.GetBaseClassName();
    const std::string &signature = originalFunction.GetSignature();
    fullName = fullName.append(namemangler::kNameSplitterStr)
                       .append(newBaseFuncName)
                       .append(namemangler::kNameSplitterStr)
                       .append(signature);
    MIRFunction *newFunc =
        mirBuilder.CreateFunction(fullName, *retType, argument, false, originalFunction.GetBody() != nullptr);
    CHECK_FATAL(newFunc != nullptr, "create cloned function failed");
    mirBuilder.GetMirModule().AddFunction(newFunc);
    Klass *klass = kh->GetKlassFromName(originalFunction.GetBaseClassName());
    CHECK_FATAL(klass != nullptr, "getklass failed");
    klass->AddMethod(newFunc);
    newFunc->SetClassTyIdx(originalFunction.GetClassTyIdx());
    MIRClassType *classType = klass->GetMIRClassType();
    DEBUG_ASSERT(newFunc->GetFuncSymbol() != nullptr, "nullpt check");
    classType->GetMethods().push_back(MethodPair(
        newFunc->GetStIdx(), TyidxFuncAttrPair(newFunc->GetFuncSymbol()->GetTyIdx(), originalFunction.GetFuncAttrs())));
    newFunc->SetFlag(originalFunction.GetFlag());
    newFunc->SetSrcPosition(originalFunction.GetSrcPosition());
    newFunc->SetFuncAttrs(originalFunction.GetFuncAttrs());
    newFunc->SetBaseClassFuncNames(GlobalTables::GetStrTable().GetOrCreateStrIdxFromName(fullName));
    if (originalFunction.GetBody() != nullptr) {
        CopyFuncInfo(originalFunction, *newFunc);
        MIRFunction *originalCurrFunction = mirBuilder.GetCurrentFunctionNotNull();
        mirBuilder.SetCurrentFunction(*newFunc);
        newFunc->SetBody(
            originalFunction.GetBody()->CloneTree(originalFunction.GetModule()->GetCurFuncCodeMPAllocator()));
        CloneSymbols(*newFunc, originalFunction);
        CloneLabels(*newFunc, originalFunction);
        mirBuilder.SetCurrentFunction(*originalCurrFunction);
    }
    return newFunc;
}

void Clone::CloneArgument(MIRFunction &originalFunction, ArgVector &argument) const
{
    for (size_t i = 0; i < originalFunction.GetFormalCount(); ++i) {
        auto &formalName = originalFunction.GetFormalName(i);
        argument.push_back(ArgPair(formalName, originalFunction.GetNthParamType(i)));
    }
}

void Clone::CopyFuncInfo(MIRFunction &originalFunction, MIRFunction &newFunc) const
{
    auto funcNameIdx = newFunc.GetBaseFuncNameStrIdx();
    auto fullNameIdx = newFunc.GetNameStrIdx();
    auto classNameIdx = newFunc.GetBaseClassNameStrIdx();
    auto metaFullNameIdx = mirBuilder.GetOrCreateStringIndex(kFullNameStr);
    auto metaClassNameIdx = mirBuilder.GetOrCreateStringIndex(kClassNameStr);
    auto metaFuncNameIdx = mirBuilder.GetOrCreateStringIndex(kFuncNameStr);
    MIRInfoVector &fnInfo = originalFunction.GetInfoVector();
    const MapleVector<bool> &infoIsString = originalFunction.InfoIsString();
    size_t size = fnInfo.size();
    for (size_t i = 0; i < size; ++i) {
        if (fnInfo[i].first == metaFullNameIdx) {
            newFunc.PushbackMIRInfo(std::pair<GStrIdx, uint32>(fnInfo[i].first, fullNameIdx));
        } else if (fnInfo[i].first == metaFuncNameIdx) {
            newFunc.PushbackMIRInfo(std::pair<GStrIdx, uint32>(fnInfo[i].first, funcNameIdx));
        } else if (fnInfo[i].first == metaClassNameIdx) {
            newFunc.PushbackMIRInfo(std::pair<GStrIdx, uint32>(fnInfo[i].first, classNameIdx));
        } else {
            newFunc.PushbackMIRInfo(std::pair<GStrIdx, uint32>(fnInfo[i].first, fnInfo[i].second));
        }
        newFunc.PushbackIsString(infoIsString[i]);
    }
}

void Clone::UpdateFuncInfo(MIRFunction &newFunc)
{
    auto fullNameIdx = newFunc.GetNameStrIdx();
    auto metaFullNameIdx = mirBuilder.GetOrCreateStringIndex(kFullNameStr);
    size_t size = newFunc.GetInfoVector().size();
    for (size_t i = 0; i < size; ++i) {
        if (newFunc.GetInfoPair(i).first == metaFullNameIdx) {
            newFunc.SetMIRInfoNum(i, fullNameIdx);
            break;
        }
    }
}

// Clone all functions that would be invoked with their return value ignored
// @param original_function The original function to be cloned
// @param mirBuilder A helper object
// @return Pointer to the newly cloned function
MIRFunction *Clone::CloneFunctionNoReturn(MIRFunction &originalFunction)
{
    const std::string kNewMethodBaseName = replaceRetIgnored->GenerateNewBaseName(originalFunction);
    MIRFunction *originalCurrFunction = mirBuilder.GetMirModule().CurFunction();
    MIRFunction *newFunction =
        CloneFunction(originalFunction, kNewMethodBaseName, GlobalTables::GetTypeTable().GetTypeFromTyIdx(1));

    // new stmt should be located in the newFunction->codemp, mirBuilder.CreateStmtReturn will use CurFunction().codemp
    // to assign space for the new stmt. So we set it correctly here.
    mirBuilder.GetMirModule().SetCurFunction(newFunction);
    if (originalFunction.GetBody() != nullptr) {
        auto *body = newFunction->GetBody();
        for (auto &stmt : body->GetStmtNodes()) {
            if (stmt.GetOpCode() == OP_return) {
                body->ReplaceStmt1WithStmt2(&stmt, mirBuilder.CreateStmtReturn(nullptr));
            }
        }
    }
    // setup new names for the newly cloned function
    std::string newFuncFullName = replaceRetIgnored->GenerateNewFullName(originalFunction);
    GStrIdx fullNameStrIdx = GlobalTables::GetStrTable().GetOrCreateStrIdxFromName(newFuncFullName);
    newFunction->OverrideBaseClassFuncNames(fullNameStrIdx);
    MIRSymbol *funcSt = newFunction->GetFuncSymbol();
    DEBUG_ASSERT(funcSt != nullptr, "nullptr check");
    GlobalTables::GetGsymTable().RemoveFromStringSymbolMap(*funcSt);
    funcSt->SetNameStrIdx(fullNameStrIdx);
    GlobalTables::GetGsymTable().AddToStringSymbolMap(*funcSt);
    UpdateFuncInfo(*newFunction);
    mirBuilder.GetMirModule().SetCurFunction(originalCurrFunction);
    return newFunction;
}

void Clone::UpdateReturnVoidIfPossible(CallMeStmt *callMeStmt, const MIRFunction &targetFunc)
{
    if (callMeStmt == nullptr) {
        return;
    }
    if (replaceRetIgnored->ShouldReplaceWithVoidFunc(*callMeStmt, targetFunc) &&
        replaceRetIgnored->IsInCloneList(targetFunc.GetName())) {
        std::string funcNameReturnVoid = replaceRetIgnored->GenerateNewFullName(targetFunc);
        GStrIdx gStrIdx = GlobalTables::GetStrTable().GetStrIdxFromName(funcNameReturnVoid);
        DEBUG_ASSERT(GlobalTables::GetGsymTable().GetSymbolFromStrIdx(gStrIdx) != nullptr,
            "nullptr check");
        MIRFunction *funcReturnVoid = GlobalTables::GetGsymTable().GetSymbolFromStrIdx(gStrIdx)->GetFunction();
        CHECK_FATAL(funcReturnVoid != nullptr, "target function not found at ssadevirtual");
        callMeStmt->SetPUIdx(funcReturnVoid->GetPuidx());
    }
}

}  // namespace maple