Source/JavaScriptCore/wasm/js/WebAssemblyModuleRecord.cpp

/*
 * Copyright (C) 2016 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
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#include "config.h"
#include "WebAssemblyModuleRecord.h"

#if ENABLE(WEBASSEMBLY)

#include "Error.h"
#include "JSCInlines.h"
#include "JSLexicalEnvironment.h"
#include "JSModuleEnvironment.h"
#include "JSWebAssemblyInstance.h"
#include "JSWebAssemblyModule.h"
#include "ProtoCallFrame.h"
#include "WasmFormat.h"
#include "WebAssemblyFunction.h"
#include <limits>

namespace JSC {

const ClassInfo WebAssemblyModuleRecord::s_info = { "WebAssemblyModuleRecord", &Base::s_info, nullptr, CREATE_METHOD_TABLE(WebAssemblyModuleRecord) };

Structure* WebAssemblyModuleRecord::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
{
    return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
}

WebAssemblyModuleRecord* WebAssemblyModuleRecord::create(ExecState* exec, VM& vm, Structure* structure, const Identifier& moduleKey, const Wasm::ModuleInformation& moduleInformation)
{
    WebAssemblyModuleRecord* instance = new (NotNull, allocateCell<WebAssemblyModuleRecord>(vm.heap)) WebAssemblyModuleRecord(vm, structure, moduleKey);
    instance->finishCreation(exec, vm, moduleInformation);
    return instance;
}

WebAssemblyModuleRecord::WebAssemblyModuleRecord(VM& vm, Structure* structure, const Identifier& moduleKey)
    : Base(vm, structure, moduleKey)
{
}

void WebAssemblyModuleRecord::destroy(JSCell* cell)
{
    WebAssemblyModuleRecord* thisObject = jsCast<WebAssemblyModuleRecord*>(cell);
    thisObject->WebAssemblyModuleRecord::~WebAssemblyModuleRecord();
}

void WebAssemblyModuleRecord::finishCreation(ExecState* exec, VM& vm, const Wasm::ModuleInformation& moduleInformation)
{
    Base::finishCreation(exec, vm);
    ASSERT(inherits(info()));
    for (const auto& exp : moduleInformation.exports) {
        switch (exp.kind) {
        case Wasm::External::Function: {
            addExportEntry(ExportEntry::createLocal(exp.field, exp.field));
            break;
        }
        case Wasm::External::Table: {
            // FIXME https://bugs.webkit.org/show_bug.cgi?id=165782
            break;
        }
        case Wasm::External::Memory: {
            // FIXME: https://bugs.webkit.org/show_bug.cgi?id=165671
            break;
        }
        case Wasm::External::Global: {
            // FIXME https://bugs.webkit.org/show_bug.cgi?id=164133
            // In the MVP, only immutable global variables can be exported.
            break;
        }
        }
    }
}

void WebAssemblyModuleRecord::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    WebAssemblyModuleRecord* thisObject = jsCast<WebAssemblyModuleRecord*>(cell);
    Base::visitChildren(thisObject, visitor);
    visitor.append(&thisObject->m_instance);
    visitor.append(&thisObject->m_startFunction);
}

void WebAssemblyModuleRecord::link(ExecState* state, JSWebAssemblyInstance* instance)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    UNUSED_PARAM(scope);
    auto* globalObject = state->lexicalGlobalObject();

    JSWebAssemblyModule* module = instance->module();
    const Wasm::ModuleInformation& moduleInformation = module->moduleInformation();

    bool hasStart = !!moduleInformation.startFunctionIndexSpace;
    auto startFunctionIndexSpace = moduleInformation.startFunctionIndexSpace.value_or(0);

    SymbolTable* exportSymbolTable = module->exportSymbolTable();
    unsigned importCount = module->importCount();

    // FIXME wire up the imports. https://bugs.webkit.org/show_bug.cgi?id=165118

    // Let exports be a list of (string, JS value) pairs that is mapped from each external value e in instance.exports as follows:
    JSModuleEnvironment* moduleEnvironment = JSModuleEnvironment::create(vm, globalObject, nullptr, exportSymbolTable, JSValue(), this);
    for (const auto& exp : moduleInformation.exports) {
        JSValue exportedValue;
        switch (exp.kind) {
        case Wasm::External::Function: {
            // 1. If e is a closure c:
            //   i. If there is an Exported Function Exotic Object func in funcs whose func.[[Closure]] equals c, then return func.
            //   ii. (Note: At most one wrapper is created for any closure, so func is unique, even if there are multiple occurrances in the list. Moreover, if the item was an import that is already an Exported Function Exotic Object, then the original function object will be found. For imports that are regular JS functions, a new wrapper will be created.)
            if (exp.functionIndex < importCount) {
                // FIXME Implement re-exporting an import. https://bugs.webkit.org/show_bug.cgi?id=165510
                RELEASE_ASSERT_NOT_REACHED();
            }
            //   iii. Otherwise:
            //     a. Let func be an Exported Function Exotic Object created from c.
            //     b. Append func to funcs.
            //     c. Return func.
            JSWebAssemblyCallee* jsEntrypointCallee = module->jsEntrypointCalleeFromFunctionIndexSpace(exp.functionIndex);
            JSWebAssemblyCallee* wasmEntrypointCallee = module->wasmEntrypointCalleeFromFunctionIndexSpace(exp.functionIndex);
            Wasm::Signature* signature = module->signatureForFunctionIndexSpace(exp.functionIndex);
            WebAssemblyFunction* function = WebAssemblyFunction::create(vm, globalObject, signature->arguments.size(), exp.field.string(), instance, jsEntrypointCallee, wasmEntrypointCallee, signature);
            exportedValue = function;
            if (hasStart && startFunctionIndexSpace == exp.functionIndex)
                m_startFunction.set(vm, this, function);
            break;
        }
        case Wasm::External::Table: {
            // FIXME https://bugs.webkit.org/show_bug.cgi?id=165782
            break;
        }
        case Wasm::External::Memory: {
            // FIXME: https://bugs.webkit.org/show_bug.cgi?id=165671
            break;
        }
        case Wasm::External::Global: {
            // FIXME https://bugs.webkit.org/show_bug.cgi?id=164133
            // In the MVP, only immutable global variables can be exported.
            break;
        }
        }

        bool shouldThrowReadOnlyError = false;
        bool ignoreReadOnlyErrors = true;
        bool putResult = false;
        symbolTablePutTouchWatchpointSet(moduleEnvironment, state, exp.field, exportedValue, shouldThrowReadOnlyError, ignoreReadOnlyErrors, putResult);
        RELEASE_ASSERT(putResult);
    }

    if (hasStart) {
        Wasm::Signature* signature = module->signatureForFunctionIndexSpace(startFunctionIndexSpace);
        // The start function must not take any arguments or return anything. This is enforced by the parser.
        ASSERT(!signature->arguments.size());
        ASSERT(signature->returnType == Wasm::Void);
        // FIXME can start call imports / tables? This assumes not. https://github.com/WebAssembly/design/issues/896
        if (!m_startFunction.get()) {
            // The start function wasn't added above. It must be a purely internal function.
            JSWebAssemblyCallee* jsEntrypointCallee = module->jsEntrypointCalleeFromFunctionIndexSpace(startFunctionIndexSpace);
            JSWebAssemblyCallee* wasmEntrypointCallee = module->wasmEntrypointCalleeFromFunctionIndexSpace(startFunctionIndexSpace);
            WebAssemblyFunction* function = WebAssemblyFunction::create(vm, globalObject, signature->arguments.size(), "start", instance, jsEntrypointCallee, wasmEntrypointCallee, signature);
            m_startFunction.set(vm, this, function);
        }
    }

    RELEASE_ASSERT(!m_instance);
    m_instance.set(vm, this, instance);
    m_moduleEnvironment.set(vm, this, moduleEnvironment);
}

JSValue WebAssemblyModuleRecord::evaluate(ExecState* state)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    if (JSWebAssemblyMemory* jsMemory = m_instance->memory()) {
        uint8_t* memory = reinterpret_cast<uint8_t*>(jsMemory->memory()->memory());
        auto sizeInBytes = jsMemory->memory()->size();
        if (memory) {
            const Vector<Wasm::Segment::Ptr>& data = m_instance->module()->moduleInformation().data;
            for (auto& segment : data) {
                if (segment->sizeInBytes) {
                    if (sizeInBytes < segment->sizeInBytes
                        || segment->offset > sizeInBytes
                        || segment->offset > sizeInBytes - segment->sizeInBytes)
                        return throwException(state, scope, createRangeError(state, ASCIILiteral("Data segment initializes memory out of range")));
                    memcpy(memory + segment->offset, &segment->byte(0), segment->sizeInBytes);
                }
            }
        }
    }

    {
        JSWebAssemblyModule* module = m_instance->module();
        const Wasm::ModuleInformation& moduleInformation = module->moduleInformation();
        JSWebAssemblyTable* table = m_instance->table();
        for (const Wasm::Element& element : moduleInformation.elements) {
            // It should be a validation error to have any elements without a table.
            // Also, it could be that a table wasn't imported, or that the table
            // imported wasn't compatible. However, those should error out before
            // getting here.
            ASSERT(!!table);
            if (!element.functionIndices.size())
                continue;

            uint32_t tableIndex = element.offset;
            uint64_t lastWrittenIndex = static_cast<uint64_t>(tableIndex) + static_cast<uint64_t>(element.functionIndices.size()) - 1;
            if (lastWrittenIndex >= table->size())
                return JSValue::decode(throwVMRangeError(state, scope, ASCIILiteral("Element is trying to set an out of bounds table index")));

            for (uint32_t i = 0; i < element.functionIndices.size(); ++i) {
                // FIXME: This essentially means we're exporting an import.
                // We need a story here. We need to create a WebAssemblyFunction
                // for the import.
                // https://bugs.webkit.org/show_bug.cgi?id=165510
                uint32_t functionIndex = element.functionIndices[i];
                if (functionIndex < module->importCount()) {
                    return JSValue::decode(
                        throwVMRangeError(state, scope, ASCIILiteral("Element is setting the table value with an import. This is not yet implemented. FIXME.")));
                }

                JSWebAssemblyCallee* jsEntrypointCallee = module->jsEntrypointCalleeFromFunctionIndexSpace(functionIndex);
                JSWebAssemblyCallee* wasmEntrypointCallee = module->wasmEntrypointCalleeFromFunctionIndexSpace(functionIndex);
                Wasm::Signature* signature = module->signatureForFunctionIndexSpace(functionIndex);
                // FIXME: Say we export local function "foo" at funciton index 0.
                // What if we also set it to the table an Element w/ index 0.
                // Does (new Instance(...)).exports.foo === table.get(0)?
                // https://bugs.webkit.org/show_bug.cgi?id=165825
                WebAssemblyFunction* function = WebAssemblyFunction::create(
                    vm, m_instance->globalObject(), signature->arguments.size(), String(), m_instance.get(), jsEntrypointCallee, wasmEntrypointCallee, signature);

                table->setFunction(vm, tableIndex, function);
                ++tableIndex;
            }
        }
    }

    if (WebAssemblyFunction* startFunction = m_startFunction.get()) {
        ProtoCallFrame protoCallFrame;
        protoCallFrame.init(nullptr, startFunction, JSValue(), 1, nullptr);
        startFunction->call(vm, &protoCallFrame);
        RETURN_IF_EXCEPTION(scope, { });
    }
    return jsUndefined();
}

} // namespace JSC

#endif // ENABLE(WEBASSEMBLY)