src/wasm/wasm-engine.cc

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/wasm/wasm-engine.h"

#include "src/objects-inl.h"
#include "src/wasm/module-compiler.h"

namespace v8 {
namespace internal {
namespace wasm {

bool WasmEngine::SyncValidate(Isolate* isolate, const ModuleWireBytes& bytes) {
  // TODO(titzer): remove dependency on the isolate.
  if (bytes.start() == nullptr || bytes.length() == 0) return false;
  ModuleResult result = SyncDecodeWasmModule(isolate, bytes.start(),
                                             bytes.end(), true, kWasmOrigin);
  return result.ok();
}

MaybeHandle<WasmModuleObject> WasmEngine::SyncCompileTranslatedAsmJs(
    Isolate* isolate, ErrorThrower* thrower, const ModuleWireBytes& bytes,
    Handle<Script> asm_js_script,
    Vector<const byte> asm_js_offset_table_bytes) {
  ModuleResult result = SyncDecodeWasmModule(isolate, bytes.start(),
                                             bytes.end(), false, kAsmJsOrigin);
  CHECK(!result.failed());

  // Transfer ownership of the WasmModule to the {WasmModuleWrapper} generated
  // in {CompileToModuleObject}.
  return CompileToModuleObject(isolate, thrower, std::move(result.val), bytes,
                               asm_js_script, asm_js_offset_table_bytes);
}

MaybeHandle<WasmModuleObject> WasmEngine::SyncCompile(
    Isolate* isolate, ErrorThrower* thrower, const ModuleWireBytes& bytes) {
  ModuleResult result = SyncDecodeWasmModule(isolate, bytes.start(),
                                             bytes.end(), false, kWasmOrigin);
  if (result.failed()) {
    thrower->CompileFailed("Wasm decoding failed", result);
    return {};
  }

  // Transfer ownership of the WasmModule to the {WasmModuleWrapper} generated
  // in {CompileToModuleObject}.
  return CompileToModuleObject(isolate, thrower, std::move(result.val), bytes,
                               Handle<Script>(), Vector<const byte>());
}

MaybeHandle<WasmInstanceObject> WasmEngine::SyncInstantiate(
    Isolate* isolate, ErrorThrower* thrower,
    Handle<WasmModuleObject> module_object, MaybeHandle<JSReceiver> imports,
    MaybeHandle<JSArrayBuffer> memory) {
  return InstantiateToInstanceObject(isolate, thrower, module_object, imports,
                                     memory);
}

void WasmEngine::AsyncInstantiate(Isolate* isolate, Handle<JSPromise> promise,
                                  Handle<WasmModuleObject> module_object,
                                  MaybeHandle<JSReceiver> imports) {
  ErrorThrower thrower(isolate, nullptr);
  MaybeHandle<WasmInstanceObject> instance_object = SyncInstantiate(
      isolate, &thrower, module_object, imports, Handle<JSArrayBuffer>::null());
  if (thrower.error()) {
    MaybeHandle<Object> result = JSPromise::Reject(promise, thrower.Reify());
    CHECK_EQ(result.is_null(), isolate->has_pending_exception());
    return;
  }
  Handle<WasmInstanceObject> instance = instance_object.ToHandleChecked();
  MaybeHandle<Object> result = JSPromise::Resolve(promise, instance);
  CHECK_EQ(result.is_null(), isolate->has_pending_exception());
}

void WasmEngine::AsyncCompile(Isolate* isolate, Handle<JSPromise> promise,
                              const ModuleWireBytes& bytes, bool is_shared) {
  if (!FLAG_wasm_async_compilation) {
    // Asynchronous compilation disabled; fall back on synchronous compilation.
    ErrorThrower thrower(isolate, "WasmCompile");
    MaybeHandle<WasmModuleObject> module_object;
    if (is_shared) {
      // Make a copy of the wire bytes to avoid concurrent modification.
      std::unique_ptr<uint8_t[]> copy(new uint8_t[bytes.length()]);
      memcpy(copy.get(), bytes.start(), bytes.length());
      i::wasm::ModuleWireBytes bytes_copy(copy.get(),
                                          copy.get() + bytes.length());
      module_object = SyncCompile(isolate, &thrower, bytes_copy);
    } else {
      // The wire bytes are not shared, OK to use them directly.
      module_object = SyncCompile(isolate, &thrower, bytes);
    }
    if (thrower.error()) {
      MaybeHandle<Object> result = JSPromise::Reject(promise, thrower.Reify());
      CHECK_EQ(result.is_null(), isolate->has_pending_exception());
      return;
    }
    Handle<WasmModuleObject> module = module_object.ToHandleChecked();
    MaybeHandle<Object> result = JSPromise::Resolve(promise, module);
    CHECK_EQ(result.is_null(), isolate->has_pending_exception());
    return;
  }

  if (FLAG_wasm_test_streaming) {
    std::shared_ptr<StreamingDecoder> streaming_decoder =
        isolate->wasm_engine()
            ->compilation_manager()
            ->StartStreamingCompilation(isolate, handle(isolate->context()),
                                        promise);
    streaming_decoder->OnBytesReceived(bytes.module_bytes());
    streaming_decoder->Finish();
    return;
  }
  // Make a copy of the wire bytes in case the user program changes them
  // during asynchronous compilation.
  std::unique_ptr<byte[]> copy(new byte[bytes.length()]);
  memcpy(copy.get(), bytes.start(), bytes.length());
  isolate->wasm_engine()->compilation_manager()->StartAsyncCompileJob(
      isolate, std::move(copy), bytes.length(), handle(isolate->context()),
      promise);
}

}  // namespace wasm
}  // namespace internal
}  // namespace v8