/*
 * Copyright (C) 2016-2019 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "JSToWasm.h"

#if ENABLE(WEBASSEMBLY)

#include "CCallHelpers.h"
#include "DisallowMacroScratchRegisterUsage.h"
#include "FrameTracers.h"
#include "JSCInlines.h"
#include "JSWebAssemblyHelpers.h"
#include "JSWebAssemblyInstance.h"
#include "JSWebAssemblyRuntimeError.h"
#include "MaxFrameExtentForSlowPathCall.h"
#include "WasmCallingConvention.h"
#include "WasmContextInlines.h"
#include "WasmSignatureInlines.h"
#include "WasmToJS.h"

namespace JSC { namespace Wasm {

inline void boxWasmResult(CCallHelpers& jit, Wasm::Type type, Reg src, JSValueRegs dst)
{
    switch (type) {
    case Wasm::Void:
        jit.moveTrustedValue(jsUndefined(), dst);
        break;
    case Wasm::Anyref:
    case Wasm::Funcref:
        jit.move(src.gpr(), dst.payloadGPR());
        break;
    case Wasm::I32:
        jit.zeroExtend32ToPtr(src.gpr(), dst.payloadGPR());
        jit.boxInt32(dst.payloadGPR(), dst, DoNotHaveTagRegisters);
        break;
    case Wasm::F32:
        jit.convertFloatToDouble(src.fpr(), src.fpr());
        FALLTHROUGH;
    case Wasm::F64: {
        jit.moveTrustedValue(jsNumber(pureNaN()), dst);
        auto isNaN = jit.branchIfNaN(src.fpr());
        jit.boxDouble(src.fpr(), dst, DoNotHaveTagRegisters);
        isNaN.link(&jit);
        break;
    }
    default:
        jit.breakpoint();
        break;
    }
}

// FIXME: It would be much easier to inline this when we have a global GC, which could probably mean we could avoid
// spilling the results onto the stack.
// Saved result registers should be placed on the stack just above the last stack result.
static JSArray* allocateResultsArray(ExecState* exec, Wasm::Instance* instance, const Signature* signature, IndexingType indexingType, JSValue* stackPointerFromCallee)
{
    JSWebAssemblyInstance* jsInstance = instance->owner<JSWebAssemblyInstance>();
    VM& vm = jsInstance->vm();
    NativeCallFrameTracer tracer(vm, exec);

    JSGlobalObject* globalObject = jsInstance->globalObject();
    ObjectInitializationScope initializationScope(globalObject->vm());
    JSArray* result = JSArray::tryCreateUninitializedRestricted(initializationScope, nullptr, globalObject->arrayStructureForIndexingTypeDuringAllocation(indexingType), signature->returnCount());

    // FIXME: Handle allocation failure...
    RELEASE_ASSERT(result);

    auto wasmCallInfo = wasmCallingConvention().callInformationFor(*signature);
    RegisterAtOffsetList registerResults = wasmCallInfo.computeResultsOffsetList();

    static_assert(sizeof(JSValue) == sizeof(CPURegister), "The code below relies on this.");
    for (unsigned i = 0; i < signature->returnCount(); ++i) {
        B3::ValueRep rep = wasmCallInfo.results[i];
        JSValue value;
        if (rep.isReg())
            value = stackPointerFromCallee[(registerResults.find(rep.reg())->offset() + wasmCallInfo.headerAndArgumentStackSizeInBytes) / sizeof(JSValue)];
        else
            value = stackPointerFromCallee[rep.offsetFromSP() / sizeof(JSValue)];
        result->initializeIndex(initializationScope, i, value);
    }

    ASSERT(result->indexingType() == indexingType);
    return result;
}

void marshallJSResult(CCallHelpers& jit, const Signature& signature, const CallInformation& wasmFrameConvention, const RegisterAtOffsetList& savedResultRegisters)
{
    if (signature.returnsVoid())
        jit.moveTrustedValue(jsUndefined(), JSValueRegs { GPRInfo::returnValueGPR });
    else if (signature.returnCount() == 1)
        boxWasmResult(jit, signature.returnType(0), wasmFrameConvention.results[0].reg(), JSValueRegs { GPRInfo::returnValueGPR });
    else {
        IndexingType indexingType = ArrayWithUndecided;
        JSValueRegs scratch = JSValueRegs { wasmCallingConvention().prologueScratchGPRs[1] };
        // We can use the first floating point register as a scratch since it will always be moved onto the stack before other values.
        FPRReg fprScratch = wasmCallingConvention().fprArgs[0].fpr();
        for (unsigned i = 0; i < signature.returnCount(); ++i) {
            B3::ValueRep rep = wasmFrameConvention.results[i];
            Type type = signature.returnType(i);

            if (rep.isReg()) {
                boxWasmResult(jit, signature.returnType(i), rep.reg(), scratch);
                jit.storeValue(scratch, CCallHelpers::Address(CCallHelpers::stackPointerRegister, savedResultRegisters.find(rep.reg())->offset() + wasmFrameConvention.headerAndArgumentStackSizeInBytes));
            } else {
                auto location = CCallHelpers::Address(CCallHelpers::stackPointerRegister, rep.offsetFromSP());
                Reg tmp = type == F32 || type == F64 ? Reg(fprScratch) : Reg(scratch.gpr());
                jit.load64ToReg(location, tmp);
                boxWasmResult(jit, signature.returnType(i), tmp, scratch);
                jit.storeValue(scratch, location);
            }

            switch (type) {
            case Wasm::I32:
                indexingType = leastUpperBoundOfIndexingTypes(indexingType, ArrayWithInt32);
                break;
            case Wasm::F32:
            case Wasm::F64:
                indexingType = leastUpperBoundOfIndexingTypes(indexingType, ArrayWithDouble);
                break;
            default:
                indexingType = leastUpperBoundOfIndexingTypes(indexingType, ArrayWithContiguous);
                break;
            }
        }

        GPRReg wasmContextInstanceGPR = PinnedRegisterInfo::get().wasmContextInstancePointer;
        if (Context::useFastTLS()) {
            wasmContextInstanceGPR = GPRInfo::argumentGPR1;
            static_assert(std::is_same_v<Wasm::Instance*, typename FunctionTraits<decltype(allocateResultsArray)>::ArgumentType<1>>);
            jit.loadWasmContextInstance(wasmContextInstanceGPR);
        }

        jit.setupArguments<decltype(allocateResultsArray)>(wasmContextInstanceGPR, CCallHelpers::TrustedImmPtr(&signature), indexingType, CCallHelpers::stackPointerRegister);
        jit.callOperation(FunctionPtr<OperationPtrTag>(allocateResultsArray));
    }
}

std::unique_ptr<InternalFunction> createJSToWasmWrapper(CompilationContext& compilationContext, const Signature& signature, Vector<UnlinkedWasmToWasmCall>* unlinkedWasmToWasmCalls, const ModuleInformation& info, MemoryMode mode, unsigned functionIndex)
{
    CCallHelpers& jit = *compilationContext.embedderEntrypointJIT;

    auto result = makeUnique<InternalFunction>();
    jit.emitFunctionPrologue();

    // FIXME Stop using 0 as codeBlocks. https://bugs.webkit.org/show_bug.cgi?id=165321
    jit.store64(CCallHelpers::TrustedImm64(0), CCallHelpers::Address(GPRInfo::callFrameRegister, CallFrameSlot::codeBlock * static_cast<int>(sizeof(Register))));
    MacroAssembler::DataLabelPtr calleeMoveLocation = jit.moveWithPatch(MacroAssembler::TrustedImmPtr(nullptr), GPRInfo::nonPreservedNonReturnGPR);
    jit.storePtr(GPRInfo::nonPreservedNonReturnGPR, CCallHelpers::Address(GPRInfo::callFrameRegister, CallFrameSlot::callee * static_cast<int>(sizeof(Register))));
    CodeLocationDataLabelPtr<WasmEntryPtrTag>* linkedCalleeMove = &result->calleeMoveLocation;
    jit.addLinkTask([=] (LinkBuffer& linkBuffer) {
        *linkedCalleeMove = linkBuffer.locationOf<WasmEntryPtrTag>(calleeMoveLocation);
    });

    const PinnedRegisterInfo& pinnedRegs = PinnedRegisterInfo::get();
    RegisterSet toSave = pinnedRegs.toSave(mode);

#if !ASSERT_DISABLED
    unsigned toSaveSize = toSave.numberOfSetGPRs();
    // They should all be callee saves.
    toSave.filter(RegisterSet::calleeSaveRegisters());
    ASSERT(toSave.numberOfSetGPRs() == toSaveSize);
#endif

    RegisterAtOffsetList registersToSpill(toSave, RegisterAtOffsetList::OffsetBaseType::FramePointerBased);
    result->entrypoint.calleeSaveRegisters = registersToSpill;

    size_t totalFrameSize = registersToSpill.size() * sizeof(CPURegister);
    CallInformation wasmFrameConvention = wasmCallingConvention().callInformationFor(signature);
    RegisterAtOffsetList savedResultRegisters = wasmFrameConvention.computeResultsOffsetList();
    totalFrameSize += wasmFrameConvention.headerAndArgumentStackSizeInBytes;
    totalFrameSize += savedResultRegisters.size() * sizeof(CPURegister);

    totalFrameSize = WTF::roundUpToMultipleOf(stackAlignmentBytes(), totalFrameSize);
    jit.subPtr(MacroAssembler::TrustedImm32(totalFrameSize), MacroAssembler::stackPointerRegister);

    // We save all these registers regardless of having a memory or not.
    // The reason is that we use one of these as a scratch. That said,
    // almost all real wasm programs use memory, so it's not really
    // worth optimizing for the case that they don't.
    for (const RegisterAtOffset& regAtOffset : registersToSpill) {
        GPRReg reg = regAtOffset.reg().gpr();
        ptrdiff_t offset = regAtOffset.offset();
        jit.storePtr(reg, CCallHelpers::Address(GPRInfo::callFrameRegister, offset));
    }

    if (wasmFrameConvention.argumentsIncludeI64 || wasmFrameConvention.resultsIncludeI64) {
        if (Context::useFastTLS())
            jit.loadWasmContextInstance(GPRInfo::argumentGPR2);
        else {
            // vmEntryToWasm passes the JSWebAssemblyInstance corresponding to Wasm::Context*'s
            // instance as the first JS argument when we're not using fast TLS to hold the
            // Wasm::Context*'s instance.
            jit.loadPtr(CCallHelpers::Address(GPRInfo::callFrameRegister, CallFrameSlot::thisArgument * sizeof(EncodedJSValue)), GPRInfo::argumentGPR2);
            jit.loadPtr(CCallHelpers::Address(GPRInfo::argumentGPR2, JSWebAssemblyInstance::offsetOfInstance()), GPRInfo::argumentGPR2);
        }

        emitThrowWasmToJSException(jit, GPRInfo::argumentGPR2, wasmFrameConvention.argumentsIncludeI64 ? ExceptionType::I64ArgumentType : ExceptionType::I64ReturnType);
        return result;
    }

    GPRReg wasmContextInstanceGPR = pinnedRegs.wasmContextInstancePointer;

    {
        CallInformation jsFrameConvention = jsCallingConvention().callInformationFor(signature, CallRole::Callee);

        CCallHelpers::Address calleeFrame = CCallHelpers::Address(MacroAssembler::stackPointerRegister, 0);

        // We're going to set the pinned registers after this. So
        // we can use this as a scratch for now since we saved it above.
        GPRReg scratchReg = pinnedRegs.baseMemoryPointer;

        if (!Context::useFastTLS()) {
            jit.loadPtr(CCallHelpers::Address(GPRInfo::callFrameRegister, JSCallingConvention::instanceStackOffset), wasmContextInstanceGPR);
            jit.loadPtr(CCallHelpers::Address(wasmContextInstanceGPR, JSWebAssemblyInstance::offsetOfInstance()), wasmContextInstanceGPR);
        }

        for (unsigned i = 0; i < signature.argumentCount(); i++) {
            RELEASE_ASSERT(jsFrameConvention.params[i].isStack());

            Type type = signature.argument(i);
            CCallHelpers::Address jsParam(GPRInfo::callFrameRegister, jsFrameConvention.params[i].offsetFromFP());
            if (wasmFrameConvention.params[i].isStackArgument()) {
                if (type == Wasm::I32 || type == Wasm::F32) {
                    jit.load32(jsParam, scratchReg);
                    jit.store32(scratchReg, calleeFrame.withOffset(wasmFrameConvention.params[i].offsetFromSP()));
                } else {
                    jit.load64(jsParam, scratchReg);
                    jit.store64(scratchReg, calleeFrame.withOffset(wasmFrameConvention.params[i].offsetFromSP()));
                }
            } else {
                if (type == Wasm::I32 || type == Wasm::F32)
                    jit.load32ToReg(jsParam, wasmFrameConvention.params[i].reg());
                else
                    jit.load64ToReg(jsParam, wasmFrameConvention.params[i].reg());
            }
        }
    }

    if (!!info.memory) {
        GPRReg baseMemory = pinnedRegs.baseMemoryPointer;
        GPRReg scratchOrSize = wasmCallingConvention().prologueScratchGPRs[0];

        if (Context::useFastTLS())
            jit.loadWasmContextInstance(baseMemory);

        GPRReg currentInstanceGPR = Context::useFastTLS() ? baseMemory : wasmContextInstanceGPR;
        if (isARM64E()) {
            if (mode != Wasm::MemoryMode::Signaling)
                scratchOrSize = pinnedRegs.sizeRegister;
            jit.loadPtr(CCallHelpers::Address(currentInstanceGPR, Wasm::Instance::offsetOfCachedMemorySize()), scratchOrSize);
        } else {
            if (mode != Wasm::MemoryMode::Signaling)
                jit.loadPtr(CCallHelpers::Address(currentInstanceGPR, Wasm::Instance::offsetOfCachedMemorySize()), pinnedRegs.sizeRegister);
        }

        jit.loadPtr(CCallHelpers::Address(currentInstanceGPR, Wasm::Instance::offsetOfCachedMemory()), baseMemory);
        jit.cageConditionally(Gigacage::Primitive, baseMemory, scratchOrSize, scratchOrSize);
    }

    CCallHelpers::Call call = jit.threadSafePatchableNearCall();
    unsigned functionIndexSpace = functionIndex + info.importFunctionCount();
    ASSERT(functionIndexSpace < info.functionIndexSpaceSize());
    jit.addLinkTask([unlinkedWasmToWasmCalls, call, functionIndexSpace] (LinkBuffer& linkBuffer) {
        unlinkedWasmToWasmCalls->append({ linkBuffer.locationOfNearCall<WasmEntryPtrTag>(call), functionIndexSpace });
    });

    marshallJSResult(jit, signature, wasmFrameConvention, savedResultRegisters);

    for (const RegisterAtOffset& regAtOffset : registersToSpill) {
        GPRReg reg = regAtOffset.reg().gpr();
        ASSERT(reg != GPRInfo::returnValueGPR);
        ptrdiff_t offset = regAtOffset.offset();
        jit.loadPtr(CCallHelpers::Address(GPRInfo::callFrameRegister, offset), reg);
    }

    jit.emitFunctionEpilogue();
    jit.ret();

    return result;
}

} } // namespace JSC::Wasm

#endif // ENABLE(WEBASSEMBLY)