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chromium / v8 / v8 / 1583e86d562b6f263d70489d4cf018c2182919dc / . / src / wasm / module-compiler.cc
blob: 13325907fcc00d245532034be8c91fd186289fac [file] [log] [blame]
// Copyright 2017 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/module-compiler.h"
#include "src/api.h"
#include "src/asmjs/asm-js.h"
#include "src/base/template-utils.h"
#include "src/base/utils/random-number-generator.h"
#include "src/compiler/wasm-compiler.h"
#include "src/counters.h"
#include "src/identity-map.h"
#include "src/property-descriptor.h"
#include "src/task-utils.h"
#include "src/tracing/trace-event.h"
#include "src/trap-handler/trap-handler.h"
#include "src/wasm/module-decoder.h"
#include "src/wasm/streaming-decoder.h"
#include "src/wasm/wasm-code-manager.h"
#include "src/wasm/wasm-engine.h"
#include "src/wasm/wasm-import-wrapper-cache-inl.h"
#include "src/wasm/wasm-js.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-memory.h"
#include "src/wasm/wasm-objects-inl.h"
#include "src/wasm/wasm-result.h"
#include "src/wasm/wasm-serialization.h"
#define TRACE(...) \
do { \
if (FLAG_trace_wasm_instances) PrintF(__VA_ARGS__); \
} while (false)
#define TRACE_COMPILE(...) \
do { \
if (FLAG_trace_wasm_compiler) PrintF(__VA_ARGS__); \
} while (false)
#define TRACE_STREAMING(...) \
do { \
if (FLAG_trace_wasm_streaming) PrintF(__VA_ARGS__); \
} while (false)
#define TRACE_LAZY(...) \
do { \
if (FLAG_trace_wasm_lazy_compilation) PrintF(__VA_ARGS__); \
} while (false)
namespace v8 {
namespace internal {
namespace wasm {
namespace {
enum class CompileMode : uint8_t { kRegular, kTiering };
// The {CompilationStateImpl} keeps track of the compilation state of the
// owning NativeModule, i.e. which functions are left to be compiled.
// It contains a task manager to allow parallel and asynchronous background
// compilation of functions.
// It's public interface {CompilationState} lives in compilation-environment.h.
class CompilationStateImpl {
public:
CompilationStateImpl(internal::Isolate*, NativeModule*);
~CompilationStateImpl();
// Cancel all background compilation and wait for all tasks to finish. Call
// this before destructing this object.
void CancelAndWait();
// Set the number of compilations unit expected to be executed. Needs to be
// set before {AddCompilationUnits} is run, which triggers background
// compilation.
void SetNumberOfFunctionsToCompile(size_t num_functions);
// Add the callback function to be called on compilation events. Needs to be
// set before {AddCompilationUnits} is run.
void AddCallback(CompilationState::callback_t);
// Inserts new functions to compile and kicks off compilation.
void AddCompilationUnits(
std::vector<std::unique_ptr<WasmCompilationUnit>>& baseline_units,
std::vector<std::unique_ptr<WasmCompilationUnit>>& tiering_units);
std::unique_ptr<WasmCompilationUnit> GetNextCompilationUnit();
std::unique_ptr<WasmCompilationUnit> GetNextExecutedUnit();
bool HasCompilationUnitToFinish();
void OnFinishedUnit(ExecutionTier);
void ScheduleCodeLogging(WasmCode*);
void OnBackgroundTaskStopped(const WasmFeatures& detected);
void PublishDetectedFeatures(Isolate* isolate, const WasmFeatures& detected);
void RestartBackgroundTasks(size_t max = std::numeric_limits<size_t>::max());
// Only one foreground thread (finisher) is allowed to run at a time.
// {SetFinisherIsRunning} returns whether the flag changed its state.
bool SetFinisherIsRunning(bool value);
void ScheduleFinisherTask();
void Abort();
void SetError(uint32_t func_index, const ResultBase& error_result);
Isolate* isolate() const { return isolate_; }
bool failed() const {
return compile_error_.load(std::memory_order_relaxed) != nullptr;
}
bool baseline_compilation_finished() const {
base::MutexGuard guard(&mutex_);
return outstanding_baseline_units_ == 0 ||
(compile_mode_ == CompileMode::kTiering &&
outstanding_tiering_units_ == 0);
}
CompileMode compile_mode() const { return compile_mode_; }
WasmFeatures* detected_features() { return &detected_features_; }
// Call {GetCompileError} from foreground threads only, since we access
// NativeModule::wire_bytes, which is set from the foreground thread once the
// stream has finished.
VoidResult GetCompileError() {
CompilationError* error = compile_error_.load(std::memory_order_acquire);
DCHECK_NOT_NULL(error);
std::ostringstream error_msg;
error_msg << "Compiling wasm function \"";
wasm::ModuleWireBytes wire_bytes(native_module_->wire_bytes());
wasm::WireBytesRef name_ref = native_module_->module()->LookupFunctionName(
wire_bytes, error->func_index);
if (name_ref.is_set()) {
wasm::WasmName name = wire_bytes.GetNameOrNull(name_ref);
error_msg.write(name.start(), name.length());
} else {
error_msg << "wasm-function[" << error->func_index << "]";
}
error_msg << "\" failed: " << error->result.error_msg();
return VoidResult::Error(error->result.error_offset(), error_msg.str());
}
std::shared_ptr<WireBytesStorage> GetSharedWireBytesStorage() const {
base::MutexGuard guard(&mutex_);
DCHECK_NOT_NULL(wire_bytes_storage_);
return wire_bytes_storage_;
}
void SetWireBytesStorage(
std::shared_ptr<WireBytesStorage> wire_bytes_storage) {
base::MutexGuard guard(&mutex_);
wire_bytes_storage_ = wire_bytes_storage;
}
std::shared_ptr<WireBytesStorage> GetWireBytesStorage() const {
base::MutexGuard guard(&mutex_);
return wire_bytes_storage_;
}
private:
struct CompilationError {
uint32_t const func_index;
VoidResult const result;
CompilationError(uint32_t func_index, const ResultBase& compile_result)
: func_index(func_index),
result(VoidResult::ErrorFrom(compile_result)) {}
};
class LogCodesTask : public CancelableTask {
public:
LogCodesTask(CancelableTaskManager* manager,
CompilationStateImpl* compilation_state, Isolate* isolate)
: CancelableTask(manager),
compilation_state_(compilation_state),
isolate_(isolate) {
// This task should only be created if we should actually log code.
DCHECK(WasmCode::ShouldBeLogged(isolate));
}
// Hold the compilation state {mutex_} when calling this method.
void AddCode(WasmCode* code) { code_to_log_.push_back(code); }
void RunInternal() override {
// Remove this task from the {CompilationStateImpl}. The next compilation
// that finishes will allocate and schedule a new task.
{
base::MutexGuard guard(&compilation_state_->mutex_);
DCHECK_EQ(this, compilation_state_->log_codes_task_);
compilation_state_->log_codes_task_ = nullptr;
}
// If by now we shouldn't log code any more, don't log it.
if (!WasmCode::ShouldBeLogged(isolate_)) return;
for (WasmCode* code : code_to_log_) {
code->LogCode(isolate_);
}
}
private:
CompilationStateImpl* const compilation_state_;
Isolate* const isolate_;
std::vector<WasmCode*> code_to_log_;
};
class FreeCallbacksTask : public CancelableTask {
public:
explicit FreeCallbacksTask(CompilationStateImpl* comp_state)
: CancelableTask(&comp_state->foreground_task_manager_),
compilation_state_(comp_state) {}
void RunInternal() override { compilation_state_->callbacks_.clear(); }
private:
CompilationStateImpl* const compilation_state_;
};
void NotifyOnEvent(CompilationEvent event, const VoidResult* error_result);
std::vector<std::unique_ptr<WasmCompilationUnit>>& finish_units() {
return baseline_compilation_finished() ? tiering_finish_units_
: baseline_finish_units_;
}
// TODO(mstarzinger): Get rid of the Isolate field to make sure the
// {CompilationStateImpl} can be shared across multiple Isolates.
Isolate* const isolate_;
NativeModule* const native_module_;
const CompileMode compile_mode_;
// Store the value of {WasmCode::ShouldBeLogged()} at creation time of the
// compilation state.
// TODO(wasm): We might lose log events if logging is enabled while
// compilation is running.
bool const should_log_code_;
// Compilation error, atomically updated, but at most once (nullptr -> error).
// Uses acquire-release semantics (acquire on load, release on update).
// For checking whether an error is set, relaxed semantics can be used.
std::atomic<CompilationError*> compile_error_{nullptr};
// This mutex protects all information of this {CompilationStateImpl} which is
// being accessed concurrently.
mutable base::Mutex mutex_;
//////////////////////////////////////////////////////////////////////////////
// Protected by {mutex_}:
std::vector<std::unique_ptr<WasmCompilationUnit>> baseline_compilation_units_;
std::vector<std::unique_ptr<WasmCompilationUnit>> tiering_compilation_units_;
bool finisher_is_running_ = false;
size_t num_background_tasks_ = 0;
std::vector<std::unique_ptr<WasmCompilationUnit>> baseline_finish_units_;
std::vector<std::unique_ptr<WasmCompilationUnit>> tiering_finish_units_;
// Features detected to be used in this module. Features can be detected
// as a module is being compiled.
WasmFeatures detected_features_ = kNoWasmFeatures;
// The foreground task to log finished wasm code. Is {nullptr} if no such task
// is currently scheduled.
LogCodesTask* log_codes_task_ = nullptr;
// Abstraction over the storage of the wire bytes. Held in a shared_ptr so
// that background compilation jobs can keep the storage alive while
// compiling.
std::shared_ptr<WireBytesStorage> wire_bytes_storage_;
size_t outstanding_baseline_units_ = 0;
size_t outstanding_tiering_units_ = 0;
// End of fields protected by {mutex_}.
//////////////////////////////////////////////////////////////////////////////
// Callback functions to be called on compilation events. Only accessible from
// the foreground thread.
std::vector<CompilationState::callback_t> callbacks_;
// Remember whether {Abort()} was called. When set from the foreground this
// ensures no more callbacks will be called afterwards. No guarantees when set
// from the background. Only needs to be atomic so that it can be set from
// foreground and background.
std::atomic<bool> aborted_{false};
CancelableTaskManager background_task_manager_;
CancelableTaskManager foreground_task_manager_;
std::shared_ptr<v8::TaskRunner> foreground_task_runner_;
const size_t max_background_tasks_ = 0;
};
void UpdateFeatureUseCounts(Isolate* isolate, const WasmFeatures& detected) {
if (detected.threads) {
isolate->CountUsage(v8::Isolate::UseCounterFeature::kWasmThreadOpcodes);
}
}
class JSToWasmWrapperCache {
public:
Handle<Code> GetOrCompileJSToWasmWrapper(Isolate* isolate, FunctionSig* sig,
bool is_import) {
std::pair<bool, FunctionSig> key(is_import, *sig);
Handle<Code>& cached = cache_[key];
if (cached.is_null()) {
cached = compiler::CompileJSToWasmWrapper(isolate, sig, is_import)
.ToHandleChecked();
}
return cached;
}
private:
// We generate different code for calling imports than calling wasm functions
// in this module. Both are cached separately.
using CacheKey = std::pair<bool, FunctionSig>;
std::unordered_map<CacheKey, Handle<Code>, base::hash<CacheKey>> cache_;
};
// A helper class to simplify instantiating a module from a module object.
// It closes over the {Isolate}, the {ErrorThrower}, etc.
class InstanceBuilder {
public:
InstanceBuilder(Isolate* isolate, ErrorThrower* thrower,
Handle<WasmModuleObject> module_object,
MaybeHandle<JSReceiver> ffi,
MaybeHandle<JSArrayBuffer> memory);
// Build an instance, in all of its glory.
MaybeHandle<WasmInstanceObject> Build();
// Run the start function, if any.
bool ExecuteStartFunction();
private:
// Represents the initialized state of a table.
struct TableInstance {
Handle<WasmTableObject> table_object; // WebAssembly.Table instance
Handle<FixedArray> js_wrappers; // JSFunctions exported
size_t table_size;
};
// A pre-evaluated value to use in import binding.
struct SanitizedImport {
Handle<String> module_name;
Handle<String> import_name;
Handle<Object> value;
};
Isolate* isolate_;
const WasmFeatures enabled_;
const WasmModule* const module_;
ErrorThrower* thrower_;
Handle<WasmModuleObject> module_object_;
MaybeHandle<JSReceiver> ffi_;
MaybeHandle<JSArrayBuffer> memory_;
Handle<JSArrayBuffer> untagged_globals_;
Handle<FixedArray> tagged_globals_;
std::vector<TableInstance> table_instances_;
std::vector<Handle<JSFunction>> js_wrappers_;
std::vector<Handle<WasmExceptionObject>> exception_wrappers_;
Handle<WasmExportedFunction> start_function_;
JSToWasmWrapperCache js_to_wasm_cache_;
std::vector<SanitizedImport> sanitized_imports_;
UseTrapHandler use_trap_handler() const {
return module_object_->native_module()->use_trap_handler() ? kUseTrapHandler
: kNoTrapHandler;
}
// Helper routines to print out errors with imports.
#define ERROR_THROWER_WITH_MESSAGE(TYPE) \
void Report##TYPE(const char* error, uint32_t index, \
Handle<String> module_name, Handle<String> import_name) { \
thrower_->TYPE("Import #%d module=\"%s\" function=\"%s\" error: %s", \
index, module_name->ToCString().get(), \
import_name->ToCString().get(), error); \
} \
\
MaybeHandle<Object> Report##TYPE(const char* error, uint32_t index, \
Handle<String> module_name) { \
thrower_->TYPE("Import #%d module=\"%s\" error: %s", index, \
module_name->ToCString().get(), error); \
return MaybeHandle<Object>(); \
}
ERROR_THROWER_WITH_MESSAGE(LinkError)
ERROR_THROWER_WITH_MESSAGE(TypeError)
#undef ERROR_THROWER_WITH_MESSAGE
// Look up an import value in the {ffi_} object.
MaybeHandle<Object> LookupImport(uint32_t index, Handle<String> module_name,
Handle<String> import_name);
// Look up an import value in the {ffi_} object specifically for linking an
// asm.js module. This only performs non-observable lookups, which allows
// falling back to JavaScript proper (and hence re-executing all lookups) if
// module instantiation fails.
MaybeHandle<Object> LookupImportAsm(uint32_t index,
Handle<String> import_name);
uint32_t EvalUint32InitExpr(const WasmInitExpr& expr);
// Load data segments into the memory.
void LoadDataSegments(Handle<WasmInstanceObject> instance);
void WriteGlobalValue(const WasmGlobal& global, double value);
void WriteGlobalValue(const WasmGlobal& global,
Handle<WasmGlobalObject> value);
void WriteGlobalAnyRef(const WasmGlobal& global, Handle<Object> value);
void SanitizeImports();
// Find the imported memory buffer if there is one. This is used to see if we
// need to recompile with bounds checks before creating the instance.
MaybeHandle<JSArrayBuffer> FindImportedMemoryBuffer() const;
// Processes a single imported function.
bool ProcessImportedFunction(Handle<WasmInstanceObject> instance,
int import_index, int func_index,
Handle<String> module_name,
Handle<String> import_name,
Handle<Object> value);
// Process a single imported table.
bool ProcessImportedTable(Handle<WasmInstanceObject> instance,
int import_index, int table_index,
Handle<String> module_name,
Handle<String> import_name, Handle<Object> value);
// Process a single imported memory.
bool ProcessImportedMemory(Handle<WasmInstanceObject> instance,
int import_index, Handle<String> module_name,
Handle<String> import_name, Handle<Object> value);
// Process a single imported global.
bool ProcessImportedGlobal(Handle<WasmInstanceObject> instance,
int import_index, int global_index,
int* next_imported_mutable_global_index,
Handle<String> module_name,
Handle<String> import_name, Handle<Object> value);
// Process a single imported WasmGlobalObject.
bool ProcessImportedWasmGlobalObject(Handle<WasmInstanceObject> instance,
int import_index,
int* next_imported_mutable_global_index,
Handle<String> module_name,
Handle<String> import_name,
const WasmGlobal& global,
Handle<WasmGlobalObject> global_object);
// Process the imports, including functions, tables, globals, and memory, in
// order, loading them from the {ffi_} object. Returns the number of imported
// functions.
int ProcessImports(Handle<WasmInstanceObject> instance);
template <typename T>
T* GetRawGlobalPtr(const WasmGlobal& global);
// Process initialization of globals.
void InitGlobals();
// Allocate memory for a module instance as a new JSArrayBuffer.
Handle<JSArrayBuffer> AllocateMemory(uint32_t num_pages);
bool NeedsWrappers() const;
// Process the exports, creating wrappers for functions, tables, memories,
// and globals.
void ProcessExports(Handle<WasmInstanceObject> instance);
void InitializeTables(Handle<WasmInstanceObject> instance);
void LoadTableSegments(Handle<WasmInstanceObject> instance);
// Creates new exception tags for all exceptions. Note that some tags might
// already exist if they were imported, those tags will be re-used.
void InitializeExceptions(Handle<WasmInstanceObject> instance);
};
CompilationStateImpl* Impl(CompilationState* compilation_state) {
return reinterpret_cast<CompilationStateImpl*>(compilation_state);
}
const CompilationStateImpl* Impl(const CompilationState* compilation_state) {
return reinterpret_cast<const CompilationStateImpl*>(compilation_state);
}
} // namespace
//////////////////////////////////////////////////////
// PIMPL implementation of {CompilationState}.
CompilationState::~CompilationState() { Impl(this)->~CompilationStateImpl(); }
void CompilationState::CancelAndWait() { Impl(this)->CancelAndWait(); }
void CompilationState::SetError(uint32_t func_index,
const ResultBase& error_result) {
Impl(this)->SetError(func_index, error_result);
}
void CompilationState::SetWireBytesStorage(
std::shared_ptr<WireBytesStorage> wire_bytes_storage) {
Impl(this)->SetWireBytesStorage(std::move(wire_bytes_storage));
}
std::shared_ptr<WireBytesStorage> CompilationState::GetWireBytesStorage()
const {
return Impl(this)->GetWireBytesStorage();
}
void CompilationState::AddCallback(CompilationState::callback_t callback) {
return Impl(this)->AddCallback(std::move(callback));
}
bool CompilationState::failed() const { return Impl(this)->failed(); }
// static
std::unique_ptr<CompilationState> CompilationState::New(
Isolate* isolate, NativeModule* native_module) {
return std::unique_ptr<CompilationState>(reinterpret_cast<CompilationState*>(
new CompilationStateImpl(isolate, native_module)));
}
// End of PIMPL implementation of {CompilationState}.
//////////////////////////////////////////////////////
MaybeHandle<WasmInstanceObject> InstantiateToInstanceObject(
Isolate* isolate, ErrorThrower* thrower,
Handle<WasmModuleObject> module_object, MaybeHandle<JSReceiver> imports,
MaybeHandle<JSArrayBuffer> memory) {
InstanceBuilder builder(isolate, thrower, module_object, imports, memory);
auto instance = builder.Build();
if (!instance.is_null() && builder.ExecuteStartFunction()) {
return instance;
}
DCHECK(isolate->has_pending_exception() || thrower->error());
return {};
}
WasmCode* LazyCompileFunction(Isolate* isolate, NativeModule* native_module,
int func_index) {
base::ElapsedTimer compilation_timer;
DCHECK(!native_module->has_code(static_cast<uint32_t>(func_index)));
compilation_timer.Start();
TRACE_LAZY("Compiling wasm-function#%d.\n", func_index);
const uint8_t* module_start = native_module->wire_bytes().start();
const WasmFunction* func = &native_module->module()->functions[func_index];
FunctionBody func_body{func->sig, func->code.offset(),
module_start + func->code.offset(),
module_start + func->code.end_offset()};
WasmCompilationUnit unit(isolate->wasm_engine(), native_module, func_index);
CompilationEnv env = native_module->CreateCompilationEnv();
unit.ExecuteCompilation(
&env, native_module->compilation_state()->GetWireBytesStorage(),
isolate->counters(),
Impl(native_module->compilation_state())->detected_features());
// During lazy compilation, we should never get compilation errors. The module
// was verified before starting execution with lazy compilation.
// This might be OOM, but then we cannot continue execution anyway.
// TODO(clemensh): According to the spec, we can actually skip validation at
// module creation time, and return a function that always traps here.
CHECK(!native_module->compilation_state()->failed());
WasmCode* code = unit.result();
if (WasmCode::ShouldBeLogged(isolate)) code->LogCode(isolate);
int64_t func_size =
static_cast<int64_t>(func->code.end_offset() - func->code.offset());
int64_t compilation_time = compilation_timer.Elapsed().InMicroseconds();
auto counters = isolate->counters();
counters->wasm_lazily_compiled_functions()->Increment();
counters->wasm_lazy_compilation_throughput()->AddSample(
compilation_time != 0 ? static_cast<int>(func_size / compilation_time)
: 0);
return code;
}
Address CompileLazy(Isolate* isolate, NativeModule* native_module,
uint32_t func_index) {
HistogramTimerScope lazy_time_scope(
isolate->counters()->wasm_lazy_compilation_time());
DCHECK(!native_module->lazy_compile_frozen());
NativeModuleModificationScope native_module_modification_scope(native_module);
WasmCode* result = LazyCompileFunction(isolate, native_module, func_index);
DCHECK_NOT_NULL(result);
DCHECK_EQ(func_index, result->index());
return result->instruction_start();
}
namespace {
// The {CompilationUnitBuilder} builds compilation units and stores them in an
// internal buffer. The buffer is moved into the working queue of the
// {CompilationStateImpl} when {Commit} is called.
class CompilationUnitBuilder {
public:
explicit CompilationUnitBuilder(NativeModule* native_module,
WasmEngine* wasm_engine)
: native_module_(native_module), wasm_engine_(wasm_engine) {}
void AddUnit(uint32_t func_index) {
switch (compilation_state()->compile_mode()) {
case CompileMode::kTiering:
tiering_units_.emplace_back(
CreateUnit(func_index, ExecutionTier::kOptimized));
baseline_units_.emplace_back(
CreateUnit(func_index, ExecutionTier::kBaseline));
return;
case CompileMode::kRegular:
baseline_units_.emplace_back(CreateUnit(
func_index, WasmCompilationUnit::GetDefaultExecutionTier()));
return;
}
UNREACHABLE();
}
bool Commit() {
if (baseline_units_.empty() && tiering_units_.empty()) return false;
compilation_state()->AddCompilationUnits(baseline_units_, tiering_units_);
Clear();
return true;
}
void Clear() {
baseline_units_.clear();
tiering_units_.clear();
}
private:
std::unique_ptr<WasmCompilationUnit> CreateUnit(uint32_t func_index,
ExecutionTier tier) {
return base::make_unique<WasmCompilationUnit>(wasm_engine_, native_module_,
func_index, tier);
}
CompilationStateImpl* compilation_state() const {
return Impl(native_module_->compilation_state());
}
NativeModule* const native_module_;
WasmEngine* const wasm_engine_;
std::vector<std::unique_ptr<WasmCompilationUnit>> baseline_units_;
std::vector<std::unique_ptr<WasmCompilationUnit>> tiering_units_;
};
bool compile_lazy(const WasmModule* module) {
return FLAG_wasm_lazy_compilation ||
(FLAG_asm_wasm_lazy_compilation && module->origin == kAsmJsOrigin);
}
byte* raw_buffer_ptr(MaybeHandle<JSArrayBuffer> buffer, int offset) {
return static_cast<byte*>(buffer.ToHandleChecked()->backing_store()) + offset;
}
void RecordStats(const Code code, Counters* counters) {
counters->wasm_generated_code_size()->Increment(code->body_size());
counters->wasm_reloc_size()->Increment(code->relocation_info()->length());
}
bool in_bounds(uint32_t offset, size_t size, size_t upper) {
return offset + size <= upper && offset + size >= offset;
}
using WasmInstanceMap =
IdentityMap<Handle<WasmInstanceObject>, FreeStoreAllocationPolicy>;
double MonotonicallyIncreasingTimeInMs() {
return V8::GetCurrentPlatform()->MonotonicallyIncreasingTime() *
base::Time::kMillisecondsPerSecond;
}
// Run by each compilation task and by the main thread (i.e. in both
// foreground and background threads). The no_finisher_callback is called
// within the result_mutex_ lock when no finishing task is running, i.e. when
// the finisher_is_running_ flag is not set.
bool FetchAndExecuteCompilationUnit(CompilationEnv* env,
CompilationStateImpl* compilation_state,
WasmFeatures* detected,
Counters* counters) {
DisallowHeapAccess no_heap_access;
std::unique_ptr<WasmCompilationUnit> unit =
compilation_state->GetNextCompilationUnit();
if (unit == nullptr) return false;
// Get the tier before starting compilation, as compilation can switch tiers
// if baseline bails out.
ExecutionTier tier = unit->tier();
unit->ExecuteCompilation(env, compilation_state->GetSharedWireBytesStorage(),
counters, detected);
if (WasmCode* result = unit->result()) {
compilation_state->ScheduleCodeLogging(result);
}
compilation_state->OnFinishedUnit(tier);
return true;
}
void InitializeCompilationUnits(NativeModule* native_module,
WasmEngine* wasm_engine) {
ModuleWireBytes wire_bytes(native_module->wire_bytes());
const WasmModule* module = native_module->module();
CompilationUnitBuilder builder(native_module, wasm_engine);
uint32_t start = module->num_imported_functions;
uint32_t end = start + module->num_declared_functions;
for (uint32_t i = start; i < end; ++i) {
builder.AddUnit(i);
}
builder.Commit();
}
void FinishCompilationUnits(CompilationStateImpl* compilation_state) {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"), "FinishCompilationUnits");
while (!compilation_state->failed()) {
std::unique_ptr<WasmCompilationUnit> unit =
compilation_state->GetNextExecutedUnit();
if (unit == nullptr) break;
}
}
void CompileInParallel(Isolate* isolate, NativeModule* native_module) {
// Data structures for the parallel compilation.
//-----------------------------------------------------------------------
// For parallel compilation:
// 1) The main thread allocates a compilation unit for each wasm function
// and stores them in the vector {compilation_units} within the
// {compilation_state}. By adding units to the {compilation_state}, new
// {BackgroundCompileTasks} instances are spawned which run on
// the background threads.
// 2) The background threads and the main thread pick one compilation unit at
// a time and execute the parallel phase of the compilation unit.
// 3) After the parallel phase of all compilation units has started, the
// main thread continues to finish all compilation units as long as
// baseline-compilation units are left to be processed.
// 4) If tier-up is enabled, the main thread restarts background tasks
// that take care of compiling and finishing the top-tier compilation
// units.
// Turn on the {CanonicalHandleScope} so that the background threads can
// use the node cache.
CanonicalHandleScope canonical(isolate);
CompilationStateImpl* compilation_state =
Impl(native_module->compilation_state());
// Make sure that no foreground task is spawned for finishing
// the compilation units. This foreground thread will be
// responsible for finishing compilation.
compilation_state->SetFinisherIsRunning(true);
uint32_t num_wasm_functions =
native_module->num_functions() - native_module->num_imported_functions();
compilation_state->SetNumberOfFunctionsToCompile(num_wasm_functions);
// 1) The main thread allocates a compilation unit for each wasm function
// and stores them in the vector {compilation_units} within the
// {compilation_state}. By adding units to the {compilation_state}, new
// {BackgroundCompileTask} instances are spawned which run on
// background threads.
InitializeCompilationUnits(native_module, isolate->wasm_engine());
// 2) The background threads and the main thread pick one compilation unit at
// a time and execute the parallel phase of the compilation unit.
WasmFeatures detected_features;
CompilationEnv env = native_module->CreateCompilationEnv();
while (FetchAndExecuteCompilationUnit(&env, compilation_state,
&detected_features,
isolate->counters()) &&
!compilation_state->baseline_compilation_finished()) {
// TODO(clemensh): Refactor ownership of the AsyncCompileJob and remove
// this.
FinishCompilationUnits(compilation_state);
if (compilation_state->failed()) break;
}
while (!compilation_state->failed()) {
// 3) After the parallel phase of all compilation units has started, the
// main thread continues to finish compilation units as long as
// baseline compilation units are left to be processed. If compilation
// already failed, all background tasks have already been canceled
// in {FinishCompilationUnits}, and there are no units to finish.
FinishCompilationUnits(compilation_state);
if (compilation_state->baseline_compilation_finished()) break;
}
// Publish features from the foreground and background tasks.
compilation_state->PublishDetectedFeatures(isolate, detected_features);
// 4) If tiering-compilation is enabled, we need to set the finisher
// to false, such that the background threads will spawn a foreground
// thread to finish the top-tier compilation units.
if (!compilation_state->failed() &&
compilation_state->compile_mode() == CompileMode::kTiering) {
compilation_state->SetFinisherIsRunning(false);
}
}
void CompileSequentially(Isolate* isolate, NativeModule* native_module,
ErrorThrower* thrower) {
DCHECK(!thrower->error());
ModuleWireBytes wire_bytes(native_module->wire_bytes());
const WasmModule* module = native_module->module();
WasmFeatures detected = kNoWasmFeatures;
auto* comp_state = Impl(native_module->compilation_state());
for (const WasmFunction& func : module->functions) {
if (func.imported) continue; // Imports are compiled at instantiation time.
// Compile the function.
WasmCompilationUnit::CompileWasmFunction(isolate, native_module, &detected,
&func);
if (comp_state->failed()) {
thrower->CompileFailed(comp_state->GetCompileError());
break;
}
}
UpdateFeatureUseCounts(isolate, detected);
}
void ValidateSequentially(Isolate* isolate, NativeModule* native_module,
ErrorThrower* thrower) {
DCHECK(!thrower->error());
ModuleWireBytes wire_bytes(native_module->wire_bytes());
const WasmModule* module = native_module->module();
uint32_t start = module->num_imported_functions;
uint32_t end = start + module->num_declared_functions;
for (uint32_t i = start; i < end; ++i) {
const WasmFunction& func = module->functions[i];
const byte* base = wire_bytes.start();
FunctionBody body{func.sig, func.code.offset(), base + func.code.offset(),
base + func.code.end_offset()};
DecodeResult result;
{
auto time_counter = SELECT_WASM_COUNTER(
isolate->counters(), module->origin, wasm_decode, function_time);
TimedHistogramScope wasm_decode_function_time_scope(time_counter);
WasmFeatures detected;
result = VerifyWasmCode(isolate->allocator(),
native_module->enabled_features(), module,
&detected, body);
}
if (result.failed()) {
TruncatedUserString<> name(wire_bytes.GetNameOrNull(&func, module));
thrower->CompileError("Compiling function #%d:%.*s failed: %s @+%u", i,
name.length(), name.start(),
result.error_msg().c_str(), result.error_offset());
break;
}
}
}
void CompileNativeModule(Isolate* isolate, ErrorThrower* thrower,
const WasmModule* wasm_module,
NativeModule* native_module) {
ModuleWireBytes wire_bytes(native_module->wire_bytes());
if (compile_lazy(wasm_module)) {
if (wasm_module->origin == kWasmOrigin) {
// Validate wasm modules for lazy compilation. Don't validate asm.js
// modules, they are valid by construction (otherwise a CHECK will fail
// during lazy compilation).
// TODO(clemensh): According to the spec, we can actually skip validation
// at module creation time, and return a function that always traps at
// (lazy) compilation time.
ValidateSequentially(isolate, native_module, thrower);
if (thrower->error()) return;
}
native_module->SetLazyBuiltin(BUILTIN_CODE(isolate, WasmCompileLazy));
} else {
size_t funcs_to_compile =
wasm_module->functions.size() - wasm_module->num_imported_functions;
bool compile_parallel =
!FLAG_trace_wasm_decoder && FLAG_wasm_num_compilation_tasks > 0 &&
funcs_to_compile > 1 &&
V8::GetCurrentPlatform()->NumberOfWorkerThreads() > 0;
if (compile_parallel) {
CompileInParallel(isolate, native_module);
} else {
CompileSequentially(isolate, native_module, thrower);
}
auto* compilation_state = Impl(native_module->compilation_state());
if (compilation_state->failed()) {
thrower->CompileFailed(compilation_state->GetCompileError());
}
}
}
// The runnable task that finishes compilation in foreground (e.g. updating
// the NativeModule, the code table, etc.).
class FinishCompileTask : public CancelableTask {
public:
explicit FinishCompileTask(CompilationStateImpl* compilation_state,
CancelableTaskManager* task_manager)
: CancelableTask(task_manager), compilation_state_(compilation_state) {}
void RunInternal() override {
Isolate* isolate = compilation_state_->isolate();
HandleScope scope(isolate);
SaveContext saved_context(isolate);
isolate->set_context(Context());
TRACE_COMPILE("(4a) Finishing compilation units...\n");
if (compilation_state_->failed()) {
compilation_state_->SetFinisherIsRunning(false);
return;
}
// We execute for 1 ms and then reschedule the task, same as the GC.
double deadline = MonotonicallyIncreasingTimeInMs() + 1.0;
while (true) {
compilation_state_->RestartBackgroundTasks();
std::unique_ptr<WasmCompilationUnit> unit =
compilation_state_->GetNextExecutedUnit();
if (unit == nullptr) {
// It might happen that a background task just scheduled a unit to be
// finished, but did not start a finisher task since the flag was still
// set. Check for this case, and continue if there is more work.
compilation_state_->SetFinisherIsRunning(false);
if (compilation_state_->HasCompilationUnitToFinish() &&
compilation_state_->SetFinisherIsRunning(true)) {
continue;
}
break;
}
if (compilation_state_->failed()) break;
if (deadline < MonotonicallyIncreasingTimeInMs()) {
// We reached the deadline. We reschedule this task and return
// immediately. Since we rescheduled this task already, we do not set
// the FinisherIsRunning flag to false.
compilation_state_->ScheduleFinisherTask();
return;
}
}
}
private:
CompilationStateImpl* compilation_state_;
};
// The runnable task that performs compilations in the background.
class BackgroundCompileTask : public CancelableTask {
public:
explicit BackgroundCompileTask(CancelableTaskManager* task_manager,
NativeModule* native_module,
Counters* counters)
: CancelableTask(task_manager),
native_module_(native_module),
counters_(counters) {}
void RunInternal() override {
TRACE_COMPILE("(3b) Compiling...\n");
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"),
"BackgroundCompileTask::RunInternal");
// The number of currently running background tasks is reduced in
// {OnBackgroundTaskStopped}.
CompilationEnv env = native_module_->CreateCompilationEnv();
auto* compilation_state = Impl(native_module_->compilation_state());
WasmFeatures detected_features = kNoWasmFeatures;
while (!compilation_state->failed()) {
if (!FetchAndExecuteCompilationUnit(&env, compilation_state,
&detected_features, counters_)) {
break;
}
}
compilation_state->OnBackgroundTaskStopped(detected_features);
}
private:
NativeModule* const native_module_;
Counters* const counters_;
};
} // namespace
std::unique_ptr<NativeModule> CompileToNativeModule(
Isolate* isolate, const WasmFeatures& enabled, ErrorThrower* thrower,
std::shared_ptr<const WasmModule> module, const ModuleWireBytes& wire_bytes,
Handle<FixedArray>* export_wrappers_out) {
const WasmModule* wasm_module = module.get();
TimedHistogramScope wasm_compile_module_time_scope(SELECT_WASM_COUNTER(
isolate->counters(), wasm_module->origin, wasm_compile, module_time));
// Embedder usage count for declared shared memories.
if (wasm_module->has_shared_memory) {
isolate->CountUsage(v8::Isolate::UseCounterFeature::kWasmSharedMemory);
}
int export_wrapper_size = static_cast<int>(module->num_exported_functions);
// TODO(wasm): only save the sections necessary to deserialize a
// {WasmModule}. E.g. function bodies could be omitted.
OwnedVector<uint8_t> wire_bytes_copy =
OwnedVector<uint8_t>::Of(wire_bytes.module_bytes());
// Create and compile the native module.
size_t code_size_estimate =
wasm::WasmCodeManager::EstimateNativeModuleCodeSize(module.get());
// Create a new {NativeModule} first.
auto native_module = isolate->wasm_engine()->code_manager()->NewNativeModule(
isolate, enabled, code_size_estimate,
wasm::NativeModule::kCanAllocateMoreMemory, std::move(module));
native_module->SetWireBytes(std::move(wire_bytes_copy));
native_module->SetRuntimeStubs(isolate);
CompileNativeModule(isolate, thrower, wasm_module, native_module.get());
if (thrower->error()) return {};
// Compile JS->wasm wrappers for exported functions.
*export_wrappers_out =
isolate->factory()->NewFixedArray(export_wrapper_size, TENURED);
CompileJsToWasmWrappers(isolate, native_module->module(),
*export_wrappers_out);
// Log the code within the generated module for profiling.
native_module->LogWasmCodes(isolate);
return native_module;
}
InstanceBuilder::InstanceBuilder(Isolate* isolate, ErrorThrower* thrower,
Handle<WasmModuleObject> module_object,
MaybeHandle<JSReceiver> ffi,
MaybeHandle<JSArrayBuffer> memory)
: isolate_(isolate),
enabled_(module_object->native_module()->enabled_features()),
module_(module_object->module()),
thrower_(thrower),
module_object_(module_object),
ffi_(ffi),
memory_(memory) {
sanitized_imports_.reserve(module_->import_table.size());
}
// Build an instance, in all of its glory.
MaybeHandle<WasmInstanceObject> InstanceBuilder::Build() {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"), "InstanceBuilder::Build");
// Check that an imports argument was provided, if the module requires it.
// No point in continuing otherwise.
if (!module_->import_table.empty() && ffi_.is_null()) {
thrower_->TypeError(
"Imports argument must be present and must be an object");
return {};
}
SanitizeImports();
if (thrower_->error()) return {};
// TODO(6792): No longer needed once WebAssembly code is off heap.
CodeSpaceMemoryModificationScope modification_scope(isolate_->heap());
// From here on, we expect the build pipeline to run without exiting to JS.
DisallowJavascriptExecution no_js(isolate_);
// Record build time into correct bucket, then build instance.
TimedHistogramScope wasm_instantiate_module_time_scope(SELECT_WASM_COUNTER(
isolate_->counters(), module_->origin, wasm_instantiate, module_time));
//--------------------------------------------------------------------------
// Allocate the memory array buffer.
//--------------------------------------------------------------------------
// We allocate the memory buffer before cloning or reusing the compiled module
// so we will know whether we need to recompile with bounds checks.
uint32_t initial_pages = module_->initial_pages;
auto initial_pages_counter = SELECT_WASM_COUNTER(
isolate_->counters(), module_->origin, wasm, min_mem_pages_count);
initial_pages_counter->AddSample(initial_pages);
// Asm.js has memory_ already set at this point, so we don't want to
// overwrite it.
if (memory_.is_null()) {
memory_ = FindImportedMemoryBuffer();
}
if (!memory_.is_null()) {
// Set externally passed ArrayBuffer non detachable.
Handle<JSArrayBuffer> memory = memory_.ToHandleChecked();
memory->set_is_detachable(false);
DCHECK_IMPLIES(use_trap_handler(), module_->origin == kAsmJsOrigin ||
memory->is_wasm_memory() ||
memory->backing_store() == nullptr);
} else if (initial_pages > 0 || use_trap_handler()) {
// We need to unconditionally create a guard region if using trap handlers,
// even when the size is zero to prevent null-dereference issues
// (e.g. https://crbug.com/769637).
// Allocate memory if the initial size is more than 0 pages.
memory_ = AllocateMemory(initial_pages);
if (memory_.is_null()) {
// failed to allocate memory
DCHECK(isolate_->has_pending_exception() || thrower_->error());
return {};
}
}
//--------------------------------------------------------------------------
// Recompile module if using trap handlers but could not get guarded memory
//--------------------------------------------------------------------------
if (module_->origin == kWasmOrigin && use_trap_handler()) {
// Make sure the memory has suitable guard regions.
WasmMemoryTracker* const memory_tracker =
isolate_->wasm_engine()->memory_tracker();
if (!memory_tracker->HasFullGuardRegions(
memory_.ToHandleChecked()->backing_store())) {
if (!FLAG_wasm_trap_handler_fallback) {
thrower_->LinkError(
"Provided memory is lacking guard regions but fallback was "
"disabled.");
return {};
}
TRACE("Recompiling module without bounds checks\n");
constexpr bool allow_trap_handler = false;
// TODO(wasm): Fix this before enabling the trap handler fallback.
USE(allow_trap_handler);
// Disable trap handlers on this native module.
NativeModule* native_module = module_object_->native_module();
native_module->DisableTrapHandler();
// Recompile all functions in this native module.
ErrorThrower thrower(isolate_, "recompile");
CompileNativeModule(isolate_, &thrower, module_, native_module);
if (thrower.error()) {
return {};
}
DCHECK(!native_module->use_trap_handler());
}
}
//--------------------------------------------------------------------------
// Create the WebAssembly.Instance object.
//--------------------------------------------------------------------------
NativeModule* native_module = module_object_->native_module();
TRACE("New module instantiation for %p\n", native_module);
Handle<WasmInstanceObject> instance =
WasmInstanceObject::New(isolate_, module_object_);
NativeModuleModificationScope native_modification_scope(native_module);
//--------------------------------------------------------------------------
// Set up the globals for the new instance.
//--------------------------------------------------------------------------
uint32_t untagged_globals_buffer_size = module_->untagged_globals_buffer_size;
if (untagged_globals_buffer_size > 0) {
void* backing_store = isolate_->array_buffer_allocator()->Allocate(
untagged_globals_buffer_size);
if (backing_store == nullptr) {
thrower_->RangeError("Out of memory: wasm globals");
return {};
}
untagged_globals_ =
isolate_->factory()->NewJSArrayBuffer(SharedFlag::kNotShared, TENURED);
constexpr bool is_external = false;
constexpr bool is_wasm_memory = false;
JSArrayBuffer::Setup(untagged_globals_, isolate_, is_external,
backing_store, untagged_globals_buffer_size,
SharedFlag::kNotShared, is_wasm_memory);
if (untagged_globals_.is_null()) {
thrower_->RangeError("Out of memory: wasm globals");
return {};
}
instance->set_globals_start(
reinterpret_cast<byte*>(untagged_globals_->backing_store()));
instance->set_untagged_globals_buffer(*untagged_globals_);
}
uint32_t tagged_globals_buffer_size = module_->tagged_globals_buffer_size;
if (tagged_globals_buffer_size > 0) {
tagged_globals_ = isolate_->factory()->NewFixedArray(
static_cast<int>(tagged_globals_buffer_size));
instance->set_tagged_globals_buffer(*tagged_globals_);
}
//--------------------------------------------------------------------------
// Set up the array of references to imported globals' array buffers.
//--------------------------------------------------------------------------
if (module_->num_imported_mutable_globals > 0) {
// TODO(binji): This allocates one slot for each mutable global, which is
// more than required if multiple globals are imported from the same
// module.
Handle<FixedArray> buffers_array = isolate_->factory()->NewFixedArray(
module_->num_imported_mutable_globals, TENURED);
instance->set_imported_mutable_globals_buffers(*buffers_array);
}
//--------------------------------------------------------------------------
// Set up the exception table used for exception tag checks.
//--------------------------------------------------------------------------
int exceptions_count = static_cast<int>(module_->exceptions.size());
if (exceptions_count > 0) {
Handle<FixedArray> exception_table =
isolate_->factory()->NewFixedArray(exceptions_count, TENURED);
instance->set_exceptions_table(*exception_table);
exception_wrappers_.resize(exceptions_count);
}
//--------------------------------------------------------------------------
// Reserve the metadata for indirect function tables.
//--------------------------------------------------------------------------
int table_count = static_cast<int>(module_->tables.size());
table_instances_.resize(table_count);
//--------------------------------------------------------------------------
// Process the imports for the module.
//--------------------------------------------------------------------------
int num_imported_functions = ProcessImports(instance);
if (num_imported_functions < 0) return {};
//--------------------------------------------------------------------------
// Process the initialization for the module's globals.
//--------------------------------------------------------------------------
InitGlobals();
//--------------------------------------------------------------------------
// Initialize the indirect tables.
//--------------------------------------------------------------------------
if (table_count > 0) {
InitializeTables(instance);
}
//--------------------------------------------------------------------------
// Initialize the exceptions table.
//--------------------------------------------------------------------------
if (exceptions_count > 0) {
InitializeExceptions(instance);
}
//--------------------------------------------------------------------------
// Create the WebAssembly.Memory object.
//--------------------------------------------------------------------------
if (module_->has_memory) {
if (!instance->has_memory_object()) {
// No memory object exists. Create one.
Handle<WasmMemoryObject> memory_object = WasmMemoryObject::New(
isolate_, memory_,
module_->maximum_pages != 0 ? module_->maximum_pages : -1);
instance->set_memory_object(*memory_object);
}
// Add the instance object to the list of instances for this memory.
Handle<WasmMemoryObject> memory_object(instance->memory_object(), isolate_);
WasmMemoryObject::AddInstance(isolate_, memory_object, instance);
if (!memory_.is_null()) {
// Double-check the {memory} array buffer matches the instance.
Handle<JSArrayBuffer> memory = memory_.ToHandleChecked();
CHECK_EQ(instance->memory_size(), memory->byte_length());
CHECK_EQ(instance->memory_start(), memory->backing_store());
}
}
//--------------------------------------------------------------------------
// Check that indirect function table segments are within bounds.
//--------------------------------------------------------------------------
for (const WasmTableInit& table_init : module_->table_inits) {
if (!table_init.active) continue;
DCHECK(table_init.table_index < table_instances_.size());
uint32_t base = EvalUint32InitExpr(table_init.offset);
size_t table_size = table_instances_[table_init.table_index].table_size;
if (!in_bounds(base, table_init.entries.size(), table_size)) {
thrower_->LinkError("table initializer is out of bounds");
return {};
}
}
//--------------------------------------------------------------------------
// Check that memory segments are within bounds.
//--------------------------------------------------------------------------
for (const WasmDataSegment& seg : module_->data_segments) {
if (!seg.active) continue;
uint32_t base = EvalUint32InitExpr(seg.dest_addr);
if (!in_bounds(base, seg.source.length(), instance->memory_size())) {
thrower_->LinkError("data segment is out of bounds");
return {};
}
}
//--------------------------------------------------------------------------
// Set up the exports object for the new instance.
//--------------------------------------------------------------------------
ProcessExports(instance);
if (thrower_->error()) return {};
//--------------------------------------------------------------------------
// Initialize the indirect function tables.
//--------------------------------------------------------------------------
if (table_count > 0) {
LoadTableSegments(instance);
}
//--------------------------------------------------------------------------
// Initialize the memory by loading data segments.
//--------------------------------------------------------------------------
if (module_->data_segments.size() > 0) {
LoadDataSegments(instance);
}
//--------------------------------------------------------------------------
// Debugging support.
//--------------------------------------------------------------------------
// Set all breakpoints that were set on the shared module.
WasmModuleObject::SetBreakpointsOnNewInstance(module_object_, instance);
if (FLAG_wasm_interpret_all && module_->origin == kWasmOrigin) {
Handle<WasmDebugInfo> debug_info =
WasmInstanceObject::GetOrCreateDebugInfo(instance);
std::vector<int> func_indexes;
for (int func_index = num_imported_functions,
num_wasm_functions = static_cast<int>(module_->functions.size());
func_index < num_wasm_functions; ++func_index) {
func_indexes.push_back(func_index);
}
WasmDebugInfo::RedirectToInterpreter(debug_info, VectorOf(func_indexes));
}
//--------------------------------------------------------------------------
// Create a wrapper for the start function.
//--------------------------------------------------------------------------
if (module_->start_function_index >= 0) {
int start_index = module_->start_function_index;
auto& function = module_->functions[start_index];
Handle<Code> wrapper_code = js_to_wasm_cache_.GetOrCompileJSToWasmWrapper(
isolate_, function.sig, function.imported);
// TODO(clemensh): Don't generate an exported function for the start
// function. Use CWasmEntry instead.
start_function_ = WasmExportedFunction::New(
isolate_, instance, MaybeHandle<String>(), start_index,
static_cast<int>(function.sig->parameter_count()), wrapper_code);
}
DCHECK(!isolate_->has_pending_exception());
TRACE("Successfully built instance for module %p\n",
module_object_->native_module());
return instance;
}
bool InstanceBuilder::ExecuteStartFunction() {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"),
"InstanceBuilder::ExecuteStartFunction");
if (start_function_.is_null()) return true; // No start function.
HandleScope scope(isolate_);
// Call the JS function.
Handle<Object> undefined = isolate_->factory()->undefined_value();
MaybeHandle<Object> retval =
Execution::Call(isolate_, start_function_, undefined, 0, nullptr);
if (retval.is_null()) {
DCHECK(isolate_->has_pending_exception());
return false;
}
return true;
}
// Look up an import value in the {ffi_} object.
MaybeHandle<Object> InstanceBuilder::LookupImport(uint32_t index,
Handle<String> module_name,
Handle<String> import_name) {
// We pre-validated in the js-api layer that the ffi object is present, and
// a JSObject, if the module has imports.
DCHECK(!ffi_.is_null());
// Look up the module first.
MaybeHandle<Object> result = Object::GetPropertyOrElement(
isolate_, ffi_.ToHandleChecked(), module_name);
if (result.is_null()) {
return ReportTypeError("module not found", index, module_name);
}
Handle<Object> module = result.ToHandleChecked();
// Look up the value in the module.
if (!module->IsJSReceiver()) {
return ReportTypeError("module is not an object or function", index,
module_name);
}
result = Object::GetPropertyOrElement(isolate_, module, import_name);
if (result.is_null()) {
ReportLinkError("import not found", index, module_name, import_name);
return MaybeHandle<JSFunction>();
}
return result;
}
// Look up an import value in the {ffi_} object specifically for linking an
// asm.js module. This only performs non-observable lookups, which allows
// falling back to JavaScript proper (and hence re-executing all lookups) if
// module instantiation fails.
MaybeHandle<Object> InstanceBuilder::LookupImportAsm(
uint32_t index, Handle<String> import_name) {
// Check that a foreign function interface object was provided.
if (ffi_.is_null()) {
return ReportLinkError("missing imports object", index, import_name);
}
// Perform lookup of the given {import_name} without causing any observable
// side-effect. We only accept accesses that resolve to data properties,
// which is indicated by the asm.js spec in section 7 ("Linking") as well.
Handle<Object> result;
LookupIterator it = LookupIterator::PropertyOrElement(
isolate_, ffi_.ToHandleChecked(), import_name);
switch (it.state()) {
case LookupIterator::ACCESS_CHECK:
case LookupIterator::INTEGER_INDEXED_EXOTIC:
case LookupIterator::INTERCEPTOR:
case LookupIterator::JSPROXY:
case LookupIterator::ACCESSOR:
case LookupIterator::TRANSITION:
return ReportLinkError("not a data property", index, import_name);
case LookupIterator::NOT_FOUND:
// Accepting missing properties as undefined does not cause any
// observable difference from JavaScript semantics, we are lenient.
result = isolate_->factory()->undefined_value();
break;
case LookupIterator::DATA:
result = it.GetDataValue();
break;
}
return result;
}
uint32_t InstanceBuilder::EvalUint32InitExpr(const WasmInitExpr& expr) {
switch (expr.kind) {
case WasmInitExpr::kI32Const:
return expr.val.i32_const;
case WasmInitExpr::kGlobalIndex: {
uint32_t offset = module_->globals[expr.val.global_index].offset;
return ReadLittleEndianValue<uint32_t>(
reinterpret_cast<Address>(raw_buffer_ptr(untagged_globals_, offset)));
}
default:
UNREACHABLE();
}
}
// Load data segments into the memory.
void InstanceBuilder::LoadDataSegments(Handle<WasmInstanceObject> instance) {
Vector<const uint8_t> wire_bytes =
module_object_->native_module()->wire_bytes();
for (const WasmDataSegment& segment : module_->data_segments) {
uint32_t source_size = segment.source.length();
// Segments of size == 0 are just nops.
if (source_size == 0) continue;
// Passive segments are not copied during instantiation.
if (!segment.active) continue;
uint32_t dest_offset = EvalUint32InitExpr(segment.dest_addr);
DCHECK(in_bounds(dest_offset, source_size, instance->memory_size()));
byte* dest = instance->memory_start() + dest_offset;
const byte* src = wire_bytes.start() + segment.source.offset();
memcpy(dest, src, source_size);
}
}
void InstanceBuilder::WriteGlobalValue(const WasmGlobal& global, double num) {
TRACE("init [globals_start=%p + %u] = %lf, type = %s\n",
reinterpret_cast<void*>(raw_buffer_ptr(untagged_globals_, 0)),
global.offset, num, ValueTypes::TypeName(global.type));
switch (global.type) {
case kWasmI32:
WriteLittleEndianValue<int32_t>(GetRawGlobalPtr<int32_t>(global),
static_cast<int32_t>(num));
break;
case kWasmI64:
WriteLittleEndianValue<int64_t>(GetRawGlobalPtr<int64_t>(global),
static_cast<int64_t>(num));
break;
case kWasmF32:
WriteLittleEndianValue<float>(GetRawGlobalPtr<float>(global),
static_cast<float>(num));
break;
case kWasmF64:
WriteLittleEndianValue<double>(GetRawGlobalPtr<double>(global),
static_cast<double>(num));
break;
default:
UNREACHABLE();
}
}
void InstanceBuilder::WriteGlobalValue(const WasmGlobal& global,
Handle<WasmGlobalObject> value) {
TRACE("init [globals_start=%p + %u] = ",
reinterpret_cast<void*>(raw_buffer_ptr(untagged_globals_, 0)),
global.offset);
switch (global.type) {
case kWasmI32: {
int32_t num = value->GetI32();
WriteLittleEndianValue<int32_t>(GetRawGlobalPtr<int32_t>(global), num);
TRACE("%d", num);
break;
}
case kWasmI64: {
int64_t num = value->GetI64();
WriteLittleEndianValue<int64_t>(GetRawGlobalPtr<int64_t>(global), num);
TRACE("%" PRId64, num);
break;
}
case kWasmF32: {
float num = value->GetF32();
WriteLittleEndianValue<float>(GetRawGlobalPtr<float>(global), num);
TRACE("%f", num);
break;
}
case kWasmF64: {
double num = value->GetF64();
WriteLittleEndianValue<double>(GetRawGlobalPtr<double>(global), num);
TRACE("%lf", num);
break;
}
default:
UNREACHABLE();
}
TRACE(", type = %s (from WebAssembly.Global)\n",
ValueTypes::TypeName(global.type));
}
void InstanceBuilder::WriteGlobalAnyRef(const WasmGlobal& global,
Handle<Object> value) {
tagged_globals_->set(global.offset, *value, UPDATE_WRITE_BARRIER);
}
void InstanceBuilder::SanitizeImports() {
Vector<const uint8_t> wire_bytes =
module_object_->native_module()->wire_bytes();
for (size_t index = 0; index < module_->import_table.size(); ++index) {
const WasmImport& import = module_->import_table[index];
Handle<String> module_name;
MaybeHandle<String> maybe_module_name =
WasmModuleObject::ExtractUtf8StringFromModuleBytes(isolate_, wire_bytes,
import.module_name);
if (!maybe_module_name.ToHandle(&module_name)) {
thrower_->LinkError("Could not resolve module name for import %zu",
index);
return;
}
Handle<String> import_name;
MaybeHandle<String> maybe_import_name =
WasmModuleObject::ExtractUtf8StringFromModuleBytes(isolate_, wire_bytes,
import.field_name);
if (!maybe_import_name.ToHandle(&import_name)) {
thrower_->LinkError("Could not resolve import name for import %zu",
index);
return;
}
int int_index = static_cast<int>(index);
MaybeHandle<Object> result =
module_->origin == kAsmJsOrigin
? LookupImportAsm(int_index, import_name)
: LookupImport(int_index, module_name, import_name);
if (thrower_->error()) {
thrower_->LinkError("Could not find value for import %zu", index);
return;
}
Handle<Object> value = result.ToHandleChecked();
sanitized_imports_.push_back({module_name, import_name, value});
}
}
MaybeHandle<JSArrayBuffer> InstanceBuilder::FindImportedMemoryBuffer() const {
DCHECK_EQ(module_->import_table.size(), sanitized_imports_.size());
for (size_t index = 0; index < module_->import_table.size(); index++) {
const WasmImport& import = module_->import_table[index];
if (import.kind == kExternalMemory) {
const auto& value = sanitized_imports_[index].value;
if (!value->IsWasmMemoryObject()) {
return {};
}
auto memory = Handle<WasmMemoryObject>::cast(value);
Handle<JSArrayBuffer> buffer(memory->array_buffer(), isolate_);
return buffer;
}
}
return {};
}
bool InstanceBuilder::ProcessImportedFunction(
Handle<WasmInstanceObject> instance, int import_index, int func_index,
Handle<String> module_name, Handle<String> import_name,
Handle<Object> value) {
// Function imports must be callable.
if (!value->IsCallable()) {
ReportLinkError("function import requires a callable", import_index,
module_name, import_name);
return false;
}
auto js_receiver = Handle<JSReceiver>::cast(value);
FunctionSig* expected_sig = module_->functions[func_index].sig;
auto kind = compiler::GetWasmImportCallKind(js_receiver, expected_sig,
enabled_.bigint);
switch (kind) {
case compiler::WasmImportCallKind::kLinkError:
ReportLinkError("imported function does not match the expected type",
import_index, module_name, import_name);
return false;
case compiler::WasmImportCallKind::kWasmToWasm: {
// The imported function is a WASM function from another instance.
auto imported_function = Handle<WasmExportedFunction>::cast(value);
Handle<WasmInstanceObject> imported_instance(
imported_function->instance(), isolate_);
// The import reference is the instance object itself.
Address imported_target = imported_function->GetWasmCallTarget();
ImportedFunctionEntry entry(instance, func_index);
entry.SetWasmToWasm(*imported_instance, imported_target);
break;
}
default: {
// The imported function is a callable.
NativeModule* native_module = instance->module_object()->native_module();
WasmCode* wasm_code = native_module->import_wrapper_cache()->GetOrCompile(
isolate_->wasm_engine(), isolate_->counters(), kind, expected_sig);
ImportedFunctionEntry entry(instance, func_index);
if (wasm_code->kind() == WasmCode::kWasmToJsWrapper) {
// Wasm to JS wrappers are treated specially in the import table.
entry.SetWasmToJs(isolate_, js_receiver, wasm_code);
} else {
// Wasm math intrinsics are compiled as regular Wasm functions.
DCHECK(kind >= compiler::WasmImportCallKind::kFirstMathIntrinsic &&
kind <= compiler::WasmImportCallKind::kLastMathIntrinsic);
entry.SetWasmToWasm(*instance, wasm_code->instruction_start());
}
break;
}
}
return true;
}
bool InstanceBuilder::ProcessImportedTable(Handle<WasmInstanceObject> instance,
int import_index, int table_index,
Handle<String> module_name,
Handle<String> import_name,
Handle<Object> value) {
if (!value->IsWasmTableObject()) {
ReportLinkError("table import requires a WebAssembly.Table", import_index,
module_name, import_name);
return false;
}
const WasmTable& table = module_->tables[table_index];
TableInstance& table_instance = table_instances_[table_index];
table_instance.table_object = Handle<WasmTableObject>::cast(value);
instance->set_table_object(*table_instance.table_object);
table_instance.js_wrappers =
Handle<FixedArray>(table_instance.table_object->functions(), isolate_);
int imported_table_size = table_instance.js_wrappers->length();
if (imported_table_size < static_cast<int>(table.initial_size)) {
thrower_->LinkError("table import %d is smaller than initial %d, got %u",
import_index, table.initial_size, imported_table_size);
return false;
}
if (table.has_maximum_size) {
int64_t imported_maximum_size =
table_instance.table_object->maximum_length()->Number();
if (imported_maximum_size < 0) {
thrower_->LinkError("table import %d has no maximum length, expected %d",
import_index, table.maximum_size);
return false;
}
if (imported_maximum_size > table.maximum_size) {
thrower_->LinkError("table import %d has a larger maximum size %" PRIx64
" than the module's declared maximum %u",
import_index, imported_maximum_size,
table.maximum_size);
return false;
}
}
// Allocate a new dispatch table.
if (!instance->has_indirect_function_table()) {
WasmInstanceObject::EnsureIndirectFunctionTableWithMinimumSize(
instance, imported_table_size);
table_instances_[table_index].table_size = imported_table_size;
}
// Initialize the dispatch table with the (foreign) JS functions
// that are already in the table.
for (int i = 0; i < imported_table_size; ++i) {
Handle<Object> val(table_instance.js_wrappers->get(i), isolate_);
// TODO(mtrofin): this is the same logic as WasmTableObject::Set:
// insert in the local table a wrapper from the other module, and add
// a reference to the owning instance of the other module.
if (!val->IsJSFunction()) continue;
if (!WasmExportedFunction::IsWasmExportedFunction(*val)) {
thrower_->LinkError("table import %d[%d] is not a wasm function",
import_index, i);
return false;
}
auto target_func = Handle<WasmExportedFunction>::cast(val);
Handle<WasmInstanceObject> target_instance =
handle(target_func->instance(), isolate_);
// Look up the signature's canonical id. If there is no canonical
// id, then the signature does not appear at all in this module,
// so putting {-1} in the table will cause checks to always fail.
FunctionSig* sig = target_func->sig();
IndirectFunctionTableEntry(instance, i)
.Set(module_->signature_map.Find(*sig), target_instance,
target_func->function_index());
}
return true;
}
bool InstanceBuilder::ProcessImportedMemory(Handle<WasmInstanceObject> instance,
int import_index,
Handle<String> module_name,
Handle<String> import_name,
Handle<Object> value) {
// Validation should have failed if more than one memory object was
// provided.
DCHECK(!instance->has_memory_object());
if (!value->IsWasmMemoryObject()) {
ReportLinkError("memory import must be a WebAssembly.Memory object",
import_index, module_name, import_name);
return false;
}
auto memory = Handle<WasmMemoryObject>::cast(value);
instance->set_memory_object(*memory);
Handle<JSArrayBuffer> buffer(memory->array_buffer(), isolate_);
// memory_ should have already been assigned in Build().
DCHECK_EQ(*memory_.ToHandleChecked(), *buffer);
uint32_t imported_cur_pages =
static_cast<uint32_t>(buffer->byte_length() / kWasmPageSize);
if (imported_cur_pages < module_->initial_pages) {
thrower_->LinkError("memory import %d is smaller than initial %u, got %u",
import_index, module_->initial_pages,
imported_cur_pages);
return false;
}
int32_t imported_maximum_pages = memory->maximum_pages();
if (module_->has_maximum_pages) {
if (imported_maximum_pages < 0) {
thrower_->LinkError(
"memory import %d has no maximum limit, expected at most %u",
import_index, imported_maximum_pages);
return false;
}
if (static_cast<uint32_t>(imported_maximum_pages) >
module_->maximum_pages) {
thrower_->LinkError(
"memory import %d has a larger maximum size %u than the "
"module's declared maximum %u",
import_index, imported_maximum_pages, module_->maximum_pages);
return false;
}
}
if (module_->has_shared_memory != buffer->is_shared()) {
thrower_->LinkError(
"mismatch in shared state of memory, declared = %d, imported = %d",
module_->has_shared_memory, buffer->is_shared());
return false;
}
return true;
}
bool InstanceBuilder::ProcessImportedWasmGlobalObject(
Handle<WasmInstanceObject> instance, int import_index,
int* next_imported_mutable_global_index, Handle<String> module_name,
Handle<String> import_name, const WasmGlobal& global,
Handle<WasmGlobalObject> global_object) {
if (global_object->type() != global.type) {
ReportLinkError("imported global does not match the expected type",
import_index, module_name, import_name);
return false;
}
if (global_object->is_mutable() != global.mutability) {
ReportLinkError("imported global does not match the expected mutability",
import_index, module_name, import_name);
return false;
}
if (global.mutability) {
Handle<JSArrayBuffer> buffer(global_object->untagged_buffer(), isolate_);
int index = (*next_imported_mutable_global_index)++;
instance->imported_mutable_globals_buffers()->set(index, *buffer);
// It is safe in this case to store the raw pointer to the buffer
// since the backing store of the JSArrayBuffer will not be
// relocated.
instance->imported_mutable_globals()[index] = reinterpret_cast<Address>(
raw_buffer_ptr(buffer, global_object->offset()));
return true;
}
WriteGlobalValue(global, global_object);
return true;
}
bool InstanceBuilder::ProcessImportedGlobal(
Handle<WasmInstanceObject> instance, int import_index, int global_index,
int* next_imported_mutable_global_index, Handle<String> module_name,
Handle<String> import_name, Handle<Object> value) {
// Immutable global imports are converted to numbers and written into
// the {untagged_globals_} array buffer.
//
// Mutable global imports instead have their backing array buffers
// referenced by this instance, and store the address of the imported
// global in the {imported_mutable_globals_} array.
const WasmGlobal& global = module_->globals[global_index];
// The mutable-global proposal allows importing i64 values, but only if
// they are passed as a WebAssembly.Global object.
//
// However, the bigint proposal allows importing constant i64 values,
// as non WebAssembly.Global object.
if (global.type == kWasmI64 && !enabled_.bigint &&
!value->IsWasmGlobalObject()) {
ReportLinkError("global import cannot have type i64", import_index,
module_name, import_name);
return false;
}
if (module_->origin == kAsmJsOrigin) {
// Accepting {JSFunction} on top of just primitive values here is a
// workaround to support legacy asm.js code with broken binding. Note
// that using {NaN} (or Smi::kZero) here is what using the observable
// conversion via {ToPrimitive} would produce as well.
// TODO(mstarzinger): Still observable if Function.prototype.valueOf
// or friends are patched, we might need to check for that as well.
if (value->IsJSFunction()) value = isolate_->factory()->nan_value();
if (value->IsPrimitive() && !value->IsSymbol()) {
if (global.type == kWasmI32) {
value = Object::ToInt32(isolate_, value).ToHandleChecked();
} else {
value = Object::ToNumber(isolate_, value).ToHandleChecked();
}
}
}
if (value->IsWasmGlobalObject()) {
auto global_object = Handle<WasmGlobalObject>::cast(value);
return ProcessImportedWasmGlobalObject(
instance, import_index, next_imported_mutable_global_index, module_name,
import_name, global, global_object);
}
if (global.mutability) {
ReportLinkError(
"imported mutable global must be a WebAssembly.Global object",
import_index, module_name, import_name);
return false;
}
if (global.type == ValueType::kWasmAnyRef) {
WriteGlobalAnyRef(global, value);
return true;
}
if (value->IsNumber()) {
WriteGlobalValue(global, value->Number());
return true;
}
if (enabled_.bigint && global.type == kWasmI64) {
Handle<BigInt> bigint;
if (!BigInt::FromObject(isolate_, value).ToHandle(&bigint)) {
return false;
}
WriteGlobalValue(global, bigint->AsInt64());
return true;
}
ReportLinkError("global import must be a number or WebAssembly.Global object",
import_index, module_name, import_name);
return false;
}
// Process the imports, including functions, tables, globals, and memory, in
// order, loading them from the {ffi_} object. Returns the number of imported
// functions.
int InstanceBuilder::ProcessImports(Handle<WasmInstanceObject> instance) {
int num_imported_functions = 0;
int num_imported_tables = 0;
int num_imported_mutable_globals = 0;
DCHECK_EQ(module_->import_table.size(), sanitized_imports_.size());
int num_imports = static_cast<int>(module_->import_table.size());
for (int index = 0; index < num_imports; ++index) {
const WasmImport& import = module_->import_table[index];
Handle<String> module_name = sanitized_imports_[index].module_name;
Handle<String> import_name = sanitized_imports_[index].import_name;
Handle<Object> value = sanitized_imports_[index].value;
switch (import.kind) {
case kExternalFunction: {
uint32_t func_index = import.index;
DCHECK_EQ(num_imported_functions, func_index);
if (!ProcessImportedFunction(instance, index, func_index, module_name,
import_name, value)) {
return -1;
}
num_imported_functions++;
break;
}
case kExternalTable: {
uint32_t table_index = import.index;
DCHECK_EQ(table_index, num_imported_tables);
if (!ProcessImportedTable(instance, index, table_index, module_name,
import_name, value)) {
return -1;
}
num_imported_tables++;
break;
}
case kExternalMemory: {
if (!ProcessImportedMemory(instance, index, module_name, import_name,
value)) {
return -1;
}
break;
}
case kExternalGlobal: {
if (!ProcessImportedGlobal(instance, index, import.index,
&num_imported_mutable_globals, module_name,
import_name, value)) {
return -1;
}
break;
}
case kExternalException: {
if (!value->IsWasmExceptionObject()) {
ReportLinkError("exception import requires a WebAssembly.Exception",
index, module_name, import_name);
return -1;
}
Handle<WasmExceptionObject> imported_exception =
Handle<WasmExceptionObject>::cast(value);
if (!imported_exception->IsSignatureEqual(
module_->exceptions[import.index].sig)) {
ReportLinkError("imported exception does not match the expected type",
index, module_name, import_name);
return -1;
}
Object exception_tag = imported_exception->exception_tag();
DCHECK(instance->exceptions_table()->get(import.index)->IsUndefined());
instance->exceptions_table()->set(import.index, exception_tag);
exception_wrappers_[import.index] = imported_exception;
break;
}
default:
UNREACHABLE();
break;
}
}
DCHECK_EQ(module_->num_imported_mutable_globals,
num_imported_mutable_globals);
return num_imported_functions;
}
template <typename T>
T* InstanceBuilder::GetRawGlobalPtr(const WasmGlobal& global) {
return reinterpret_cast<T*>(raw_buffer_ptr(untagged_globals_, global.offset));
}
// Process initialization of globals.
void InstanceBuilder::InitGlobals() {
for (auto global : module_->globals) {
if (global.mutability && global.imported) {
continue;
}
switch (global.init.kind) {
case WasmInitExpr::kI32Const:
WriteLittleEndianValue<int32_t>(GetRawGlobalPtr<int32_t>(global),
global.init.val.i32_const);
break;
case WasmInitExpr::kI64Const:
WriteLittleEndianValue<int64_t>(GetRawGlobalPtr<int64_t>(global),
global.init.val.i64_const);
break;
case WasmInitExpr::kF32Const:
WriteLittleEndianValue<float>(GetRawGlobalPtr<float>(global),
global.init.val.f32_const);
break;
case WasmInitExpr::kF64Const:
WriteLittleEndianValue<double>(GetRawGlobalPtr<double>(global),
global.init.val.f64_const);
break;
case WasmInitExpr::kAnyRefConst:
DCHECK(enabled_.anyref);
if (global.imported) break; // We already initialized imported globals.
tagged_globals_->set(global.offset,
ReadOnlyRoots(isolate_).null_value(),
SKIP_WRITE_BARRIER);
break;
case WasmInitExpr::kGlobalIndex: {
if (global.type == ValueType::kWasmAnyRef) {
DCHECK(enabled_.anyref);
int other_offset =
module_->globals[global.init.val.global_index].offset;
tagged_globals_->set(global.offset,
tagged_globals_->get(other_offset),
SKIP_WRITE_BARRIER);
}
// Initialize with another global.
uint32_t new_offset = global.offset;
uint32_t old_offset =
module_->globals[global.init.val.global_index].offset;
TRACE("init [globals+%u] = [globals+%d]\n", global.offset, old_offset);
size_t size = (global.type == kWasmI64 || global.type == kWasmF64)
? sizeof(double)
: sizeof(int32_t);
memcpy(raw_buffer_ptr(untagged_globals_, new_offset),
raw_buffer_ptr(untagged_globals_, old_offset), size);
break;
}
case WasmInitExpr::kNone:
// Happens with imported globals.
break;
default:
UNREACHABLE();
break;
}
}
}
// Allocate memory for a module instance as a new JSArrayBuffer.
Handle<JSArrayBuffer> InstanceBuilder::AllocateMemory(uint32_t num_pages) {
if (num_pages > max_mem_pages()) {
thrower_->RangeError("Out of memory: wasm memory too large");
return Handle<JSArrayBuffer>::null();
}
const bool is_shared_memory = module_->has_shared_memory && enabled_.threads;
SharedFlag shared_flag =
is_shared_memory ? SharedFlag::kShared : SharedFlag::kNotShared;
Handle<JSArrayBuffer> mem_buffer;
if (!NewArrayBuffer(isolate_, num_pages * kWasmPageSize, shared_flag)
.ToHandle(&mem_buffer)) {
thrower_->RangeError("Out of memory: wasm memory");
}
return mem_buffer;
}
bool InstanceBuilder::NeedsWrappers() const {
if (module_->num_exported_functions > 0) return true;
for (auto& table_instance : table_instances_) {
if (!table_instance.js_wrappers.is_null()) return true;
}
for (auto& table : module_->tables) {
if (table.exported) return true;
}
return false;
}
// Process the exports, creating wrappers for functions, tables, memories,
// globals, and exceptions.
void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
Handle<FixedArray> export_wrappers(module_object_->export_wrappers(),
isolate_);
if (NeedsWrappers()) {
// Fill the table to cache the exported JSFunction wrappers.
js_wrappers_.insert(js_wrappers_.begin(), module_->functions.size(),
Handle<JSFunction>::null());
// If an imported WebAssembly function gets exported, the exported function
// has to be identical to to imported function. Therefore we put all
// imported WebAssembly functions into the js_wrappers_ list.
for (int index = 0, end = static_cast<int>(module_->import_table.size());
index < end; ++index) {
const WasmImport& import = module_->import_table[index];
if (import.kind == kExternalFunction) {
Handle<Object> value = sanitized_imports_[index].value;
if (WasmExportedFunction::IsWasmExportedFunction(*value)) {
js_wrappers_[import.index] = Handle<JSFunction>::cast(value);
}
}
}
}
Handle<JSObject> exports_object;
bool is_asm_js = false;
switch (module_->origin) {
case kWasmOrigin: {
// Create the "exports" object.
exports_object = isolate_->factory()->NewJSObjectWithNullProto();
break;
}
case kAsmJsOrigin: {
Handle<JSFunction> object_function = Handle<JSFunction>(
isolate_->native_context()->object_function(), isolate_);
exports_object = isolate_->factory()->NewJSObject(object_function);
is_asm_js = true;
break;
}
default:
UNREACHABLE();
}
instance->set_exports_object(*exports_object);
Handle<String> single_function_name =
isolate_->factory()->InternalizeUtf8String(AsmJs::kSingleFunctionName);
PropertyDescriptor desc;
desc.set_writable(is_asm_js);
desc.set_enumerable(true);
desc.set_configurable(is_asm_js);
// Process each export in the export table.
int export_index = 0; // Index into {export_wrappers}.
for (const WasmExport& exp : module_->export_table) {
Handle<String> name = WasmModuleObject::ExtractUtf8StringFromModuleBytes(
isolate_, module_object_, exp.name)
.ToHandleChecked();
Handle<JSObject> export_to;
if (is_asm_js && exp.kind == kExternalFunction &&
String::Equals(isolate_, name, single_function_name)) {
export_to = instance;
} else {
export_to = exports_object;
}
switch (exp.kind) {
case kExternalFunction: {
// Wrap and export the code as a JSFunction.
const WasmFunction& function = module_->functions[exp.index];
Handle<JSFunction> js_function = js_wrappers_[exp.index];
if (js_function.is_null()) {
// Wrap the exported code as a JSFunction.
Handle<Code> export_code =
export_wrappers->GetValueChecked<Code>(isolate_, export_index);
MaybeHandle<String> func_name;
if (is_asm_js) {
// For modules arising from asm.js, honor the names section.
WireBytesRef func_name_ref = module_->LookupFunctionName(
ModuleWireBytes(module_object_->native_module()->wire_bytes()),
function.func_index);
func_name = WasmModuleObject::ExtractUtf8StringFromModuleBytes(
isolate_, module_object_, func_name_ref)
.ToHandleChecked();
}
js_function = WasmExportedFunction::New(
isolate_, instance, func_name, function.func_index,
static_cast<int>(function.sig->parameter_count()), export_code);
js_wrappers_[exp.index] = js_function;
}
desc.set_value(js_function);
export_index++;
break;
}
case kExternalTable: {
// Export a table as a WebAssembly.Table object.
TableInstance& table_instance = table_instances_[exp.index];
const WasmTable& table = module_->tables[exp.index];
if (table_instance.table_object.is_null()) {
uint32_t maximum = table.has_maximum_size ? table.maximum_size
: FLAG_wasm_max_table_size;
table_instance.table_object =
WasmTableObject::New(isolate_, table.initial_size, maximum,
&table_instance.js_wrappers);
}
desc.set_value(table_instance.table_object);
break;
}
case kExternalMemory: {
// Export the memory as a WebAssembly.Memory object. A WasmMemoryObject
// should already be available if the module has memory, since we always
// create or import it when building an WasmInstanceObject.
DCHECK(instance->has_memory_object());
desc.set_value(
Handle<WasmMemoryObject>(instance->memory_object(), isolate_));
break;
}
case kExternalGlobal: {
const WasmGlobal& global = module_->globals[exp.index];
Handle<JSArrayBuffer> untagged_buffer;
Handle<FixedArray> tagged_buffer;
uint32_t offset;
if (global.mutability && global.imported) {
Handle<FixedArray> buffers_array(
instance->imported_mutable_globals_buffers(), isolate_);
untagged_buffer = buffers_array->GetValueChecked<JSArrayBuffer>(
isolate_, global.index);
Address global_addr =
instance->imported_mutable_globals()[global.index];
size_t buffer_size = untagged_buffer->byte_length();
Address backing_store =
reinterpret_cast<Address>(untagged_buffer->backing_store());
CHECK(global_addr >= backing_store &&
global_addr < backing_store + buffer_size);
offset = static_cast<uint32_t>(global_addr - backing_store);
} else {
if (global.type == kWasmAnyRef) {
tagged_buffer = handle(instance->tagged_globals_buffer(), isolate_);
} else {
untagged_buffer =
handle(instance->untagged_globals_buffer(), isolate_);
}
offset = global.offset;
}
// Since the global's array untagged_buffer is always provided,
// allocation should never fail.
Handle<WasmGlobalObject> global_obj =
WasmGlobalObject::New(isolate_, untagged_buffer, tagged_buffer,
global.type, offset, global.mutability)
.ToHandleChecked();
desc.set_value(global_obj);
break;
}
case kExternalException: {
const WasmException& exception = module_->exceptions[exp.index];
Handle<WasmExceptionObject> wrapper = exception_wrappers_[exp.index];
if (wrapper.is_null()) {
Handle<HeapObject> exception_tag(
HeapObject::cast(instance->exceptions_table()->get(exp.index)),
isolate_);
wrapper =
WasmExceptionObject::New(isolate_, exception.sig, exception_tag);
exception_wrappers_[exp.index] = wrapper;
}
desc.set_value(wrapper);
break;
}
default:
UNREACHABLE();
break;
}
v8::Maybe<bool> status = JSReceiver::DefineOwnProperty(
isolate_, export_to, name, &desc, kThrowOnError);
if (!status.IsJust()) {
DisallowHeapAllocation no_gc;
TruncatedUserString<> trunc_name(name->GetCharVector<uint8_t>(no_gc));
thrower_->LinkError("export of %.*s failed.", trunc_name.length(),
trunc_name.start());
return;
}
}
DCHECK_EQ(export_index, export_wrappers->length());
if (module_->origin == kWasmOrigin) {
v8::Maybe<bool> success =
JSReceiver::SetIntegrityLevel(exports_object, FROZEN, kDontThrow);
DCHECK(success.FromMaybe(false));
USE(success);
}
}
void InstanceBuilder::InitializeTables(Handle<WasmInstanceObject> instance) {
size_t table_count = module_->tables.size();
for (size_t index = 0; index < table_count; ++index) {
const WasmTable& table = module_->tables[index];
TableInstance& table_instance = table_instances_[index];
if (!instance->has_indirect_function_table() &&
table.type == kWasmAnyFunc) {
WasmInstanceObject::EnsureIndirectFunctionTableWithMinimumSize(
instance, table.initial_size);
table_instance.table_size = table.initial_size;
}
}
}
void InstanceBuilder::LoadTableSegments(Handle<WasmInstanceObject> instance) {
NativeModule* native_module = module_object_->native_module();
for (auto& table_init : module_->table_inits) {
// Passive segments are not copied during instantiation.
if (!table_init.active) continue;
uint32_t base = EvalUint32InitExpr(table_init.offset);
uint32_t num_entries = static_cast<uint32_t>(table_init.entries.size());
uint32_t index = table_init.table_index;
TableInstance& table_instance = table_instances_[index];
DCHECK(in_bounds(base, num_entries, table_instance.table_size));
for (uint32_t i = 0; i < num_entries; ++i) {
uint32_t func_index = table_init.entries[i];
const WasmFunction* function = &module_->functions[func_index];
int table_index = static_cast<int>(i + base);
// Update the local dispatch table first.
uint32_t sig_id = module_->signature_ids[function->sig_index];
IndirectFunctionTableEntry(instance, table_index)
.Set(sig_id, instance, func_index);
if (!table_instance.table_object.is_null()) {
// Update the table object's other dispatch tables.
if (js_wrappers_[func_index].is_null()) {
// No JSFunction entry yet exists for this function. Create one.
// TODO(titzer): We compile JS->wasm wrappers for functions are
// not exported but are in an exported table. This should be done
// at module compile time and cached instead.
Handle<Code> wrapper_code =
js_to_wasm_cache_.GetOrCompileJSToWasmWrapper(
isolate_, function->sig, function->imported);
MaybeHandle<String> func_name;
if (module_->origin == kAsmJsOrigin) {
// For modules arising from asm.js, honor the names section.
WireBytesRef func_name_ref = module_->LookupFunctionName(
ModuleWireBytes(native_module->wire_bytes()), func_index);
func_name = WasmModuleObject::ExtractUtf8StringFromModuleBytes(
isolate_, module_object_, func_name_ref)
.ToHandleChecked();
}
Handle<WasmExportedFunction> js_function = WasmExportedFunction::New(
isolate_, instance, func_name, func_index,
static_cast<int>(function->sig->parameter_count()), wrapper_code);
js_wrappers_[func_index] = js_function;
}
table_instance.js_wrappers->set(table_index, *js_wrappers_[func_index]);
// UpdateDispatchTables() updates all other dispatch tables, since
// we have not yet added the dispatch table we are currently building.
WasmTableObject::UpdateDispatchTables(
isolate_, table_instance.table_object, table_index, function->sig,
instance, func_index);
}
}
}
int table_count = static_cast<int>(module_->tables.size());
for (int index = 0; index < table_count; ++index) {
TableInstance& table_instance = table_instances_[index];
// Add the new dispatch table at the end to avoid redundant lookups.
if (!table_instance.table_object.is_null()) {
WasmTableObject::AddDispatchTable(isolate_, table_instance.table_object,
instance, index);
}
}
}
void InstanceBuilder::InitializeExceptions(
Handle<WasmInstanceObject> instance) {
Handle<FixedArray> exceptions_table(instance->exceptions_table(), isolate_);
for (int index = 0; index < exceptions_table->length(); ++index) {
if (!exceptions_table->get(index)->IsUndefined(isolate_)) continue;
Handle<WasmExceptionTag> exception_tag =
WasmExceptionTag::New(isolate_, index);
exceptions_table->set(index, *exception_tag);
}
}
AsyncCompileJob::AsyncCompileJob(
Isolate* isolate, const WasmFeatures& enabled,
std::unique_ptr<byte[]> bytes_copy, size_t length, Handle<Context> context,
std::shared_ptr<CompilationResultResolver> resolver)
: isolate_(isolate),
enabled_features_(enabled),
bytes_copy_(std::move(bytes_copy)),
wire_bytes_(bytes_copy_.get(), bytes_copy_.get() + length),
resolver_(std::move(resolver)) {
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
v8::Platform* platform = V8::GetCurrentPlatform();
foreground_task_runner_ = platform->GetForegroundTaskRunner(v8_isolate);
// The handle for the context must be deferred.
DeferredHandleScope deferred(isolate);
native_context_ = Handle<Context>(context->native_context(), isolate);
DCHECK(native_context_->IsNativeContext());
deferred_handles_.push_back(deferred.Detach());
}
void AsyncCompileJob::Start() {
DoAsync<DecodeModule>(isolate_->counters()); // --
}
void AsyncCompileJob::Abort() {
// Removing this job will trigger the destructor, which will cancel all
// compilation.
isolate_->wasm_engine()->RemoveCompileJob(this);
}
class AsyncStreamingProcessor final : public StreamingProcessor {
public:
explicit AsyncStreamingProcessor(AsyncCompileJob* job);
bool ProcessModuleHeader(Vector<const uint8_t> bytes,
uint32_t offset) override;
bool ProcessSection(SectionCode section_code, Vector<const uint8_t> bytes,
uint32_t offset) override;
bool ProcessCodeSectionHeader(size_t functions_count, uint32_t offset,
std::shared_ptr<WireBytesStorage>) override;
bool ProcessFunctionBody(Vector<const uint8_t> bytes,
uint32_t offset) override;
void OnFinishedChunk() override;
void OnFinishedStream(OwnedVector<uint8_t> bytes) override;
void OnError(DecodeResult result) override;
void OnAbort() override;
bool Deserialize(Vector<const uint8_t> wire_bytes,
Vector<const uint8_t> module_bytes) override;
private:
// Finishes the AsyncCompileJob with an error.
void FinishAsyncCompileJobWithError(ResultBase result);
void CommitCompilationUnits();
ModuleDecoder decoder_;
AsyncCompileJob* job_;
std::unique_ptr<CompilationUnitBuilder> compilation_unit_builder_;
uint32_t next_function_ = 0;
};
std::shared_ptr<StreamingDecoder> AsyncCompileJob::CreateStreamingDecoder() {
DCHECK_NULL(stream_);
stream_.reset(
new StreamingDecoder(base::make_unique<AsyncStreamingProcessor>(this)));
return stream_;
}
AsyncCompileJob::~AsyncCompileJob() {
background_task_manager_.CancelAndWait();
if (native_module_) Impl(native_module_->compilation_state())->Abort();
// Tell the streaming decoder that the AsyncCompileJob is not available
// anymore.
// TODO(ahaas): Is this notification really necessary? Check
// https://crbug.com/888170.
if (stream_) stream_->NotifyCompilationEnded();
CancelPendingForegroundTask();
for (auto d : deferred_handles_) delete d;
}
void AsyncCompileJob::CreateNativeModule(
std::shared_ptr<const WasmModule> module) {
// Embedder usage count for declared shared memories.
if (module->has_shared_memory) {
isolate_->CountUsage(v8::Isolate::UseCounterFeature::kWasmSharedMemory);
}
// TODO(wasm): Improve efficiency of storing module wire bytes. Only store
// relevant sections, not function bodies
// Create the module object and populate with compiled functions and
// information needed at instantiation time.
// TODO(clemensh): For the same module (same bytes / same hash), we should
// only have one {WasmModuleObject}. Otherwise, we might only set
// breakpoints on a (potentially empty) subset of the instances.
// Create the module object.
size_t code_size_estimate =
wasm::WasmCodeManager::EstimateNativeModuleCodeSize(module.get());
native_module_ = isolate_->wasm_engine()->code_manager()->NewNativeModule(
isolate_, enabled_features_, code_size_estimate,
wasm::NativeModule::kCanAllocateMoreMemory, std::move(module));
native_module_->SetWireBytes({std::move(bytes_copy_), wire_bytes_.length()});
native_module_->SetRuntimeStubs(isolate_);
if (stream_) stream_->NotifyNativeModuleCreated(native_module_);
}
void AsyncCompileJob::PrepareRuntimeObjects() {
// Create heap objects for script and module bytes to be stored in the
// module object. Asm.js is not compiled asynchronously.
const WasmModule* module = native_module_->module();
Handle<Script> script =
CreateWasmScript(isolate_, wire_bytes_, module->source_map_url);
size_t code_size_estimate =
wasm::WasmCodeManager::EstimateNativeModuleCodeSize(module);
module_object_ = WasmModuleObject::New(isolate_, native_module_, script,
code_size_estimate);
{
DeferredHandleScope deferred(isolate_);
module_object_ = handle(*module_object_, isolate_);
deferred_handles_.push_back(deferred.Detach());
}
}
// This function assumes that it is executed in a HandleScope, and that a
// context is set on the isolate.
void AsyncCompileJob::FinishCompile() {
bool is_after_deserialization = !module_object_.is_null();
if (!is_after_deserialization) {
PrepareRuntimeObjects();
}
DCHECK(!isolate_->context().is_null());
// Finish the wasm script now and make it public to the debugger.
Handle<Script> script(module_object_->script(), isolate_);
if (script->type() == Script::TYPE_WASM &&
module_object_->module()->source_map_url.size() != 0) {
MaybeHandle<String> src_map_str = isolate_->factory()->NewStringFromUtf8(
CStrVector(module_object_->module()->source_map_url.c_str()), TENURED);
script->set_source_mapping_url(*src_map_str.ToHandleChecked());
}
isolate_->debug()->OnAfterCompile(script);
// We can only update the feature counts once the entire compile is done.
auto compilation_state =
Impl(module_object_->native_module()->compilation_state());
compilation_state->PublishDetectedFeatures(
isolate_, *compilation_state->detected_features());
// TODO(bbudge) Allow deserialization without wrapper compilation, so we can
// just compile wrappers here.
if (!is_after_deserialization) {
// TODO(wasm): compiling wrappers should be made async.
CompileWrappers();
}
FinishModule();
}
void AsyncCompileJob::AsyncCompileFailed(Handle<Object> error_reason) {
// {job} keeps the {this} pointer alive.
std::shared_ptr<AsyncCompileJob> job =
isolate_->wasm_engine()->RemoveCompileJob(this);
resolver_->OnCompilationFailed(error_reason);
}
void AsyncCompileJob::AsyncCompileSucceeded(Handle<WasmModuleObject> result) {
resolver_->OnCompilationSucceeded(result);
}
class AsyncCompileJob::CompilationStateCallback {
public:
explicit CompilationStateCallback(AsyncCompileJob* job) : job_(job) {}
void operator()(CompilationEvent event, const ResultBase* error_result) {
// This callback is only being called from a foreground task.
switch (event) {
case CompilationEvent::kFinishedBaselineCompilation:
DCHECK(!last_event_.has_value());
if (job_->DecrementAndCheckFinisherCount()) {
SaveContext saved_context(job_->isolate());
job_->isolate()->set_context(*job_->native_context_);
job_->FinishCompile();
}
break;
case CompilationEvent::kFinishedTopTierCompilation:
DCHECK_EQ(CompilationEvent::kFinishedBaselineCompilation, last_event_);
// If a foreground task or a finisher is pending, we rely on
// FinishModule to remove the job.
if (!job_->pending_foreground_task_ &&
job_->outstanding_finishers_.load() == 0) {
job_->isolate_->wasm_engine()->RemoveCompileJob(job_);
}
break;
case CompilationEvent::kFailedCompilation:
DCHECK(!last_event_.has_value());
DCHECK_NOT_NULL(error_result);
// Tier-up compilation should not fail if baseline compilation
// did not fail.
DCHECK(!Impl(job_->native_module_->compilation_state())
->baseline_compilation_finished());
{
SaveContext saved_context(job_->isolate());
job_->isolate()->set_context(*job_->native_context_);
ErrorThrower thrower(job_->isolate(), "AsyncCompilation");
thrower.CompileFailed(*error_result);
Handle<Object> error = thrower.Reify();
DeferredHandleScope deferred(job_->isolate());
error = handle(*error, job_->isolate());
job_->deferred_handles_.push_back(deferred.Detach());
job_->DoSync<CompileFailed, kUseExistingForegroundTask>(error);
}
break;
default:
UNREACHABLE();
}
#ifdef DEBUG
last_event_ = event;
#endif
}
private:
AsyncCompileJob* job_;
#ifdef DEBUG
base::Optional<CompilationEvent> last_event_;
#endif
};
// A closure to run a compilation step (either as foreground or background
// task) and schedule the next step(s), if any.
class AsyncCompileJob::CompileStep {
public:
virtual ~CompileStep() = default;
void Run(AsyncCompileJob* job, bool on_foreground) {
if (on_foreground) {
HandleScope scope(job->isolate_);
SaveContext saved_context(job->isolate_);
job->isolate_->set_context(*job->native_context_);
RunInForeground(job);
} else {
RunInBackground(job);
}
}
virtual void RunInForeground(AsyncCompileJob*) { UNREACHABLE(); }
virtual void RunInBackground(AsyncCompileJob*) { UNREACHABLE(); }
};
class AsyncCompileJob::CompileTask : public CancelableTask {
public:
CompileTask(AsyncCompileJob* job, bool on_foreground)
// We only manage the background tasks with the {CancelableTaskManager} of
// the {AsyncCompileJob}. Foreground tasks are managed by the system's
// {CancelableTaskManager}. Background tasks cannot spawn tasks managed by
// their own task manager.
: CancelableTask(on_foreground ? job->isolate_->cancelable_task_manager()
: &job->background_task_manager_),
job_(job),
on_foreground_(on_foreground) {}
~CompileTask() override {
if (job_ != nullptr && on_foreground_) ResetPendingForegroundTask();
}
void RunInternal() final {
if (!job_) return;
if (on_foreground_) ResetPendingForegroundTask();
job_->step_->Run(job_, on_foreground_);
// After execution, reset {job_} such that we don't try to reset the pending
// foreground task when the task is deleted.
job_ = nullptr;
}
void Cancel() {
DCHECK_NOT_NULL(job_);
job_ = nullptr;
}
private:
// {job_} will be cleared to cancel a pending task.
AsyncCompileJob* job_;
bool on_foreground_;
void ResetPendingForegroundTask() const {
DCHECK_EQ(this, job_->pending_foreground_task_);
job_->pending_foreground_task_ = nullptr;
}
};
void AsyncCompileJob::StartForegroundTask() {
DCHECK_NULL(pending_foreground_task_);
auto new_task = base::make_unique<CompileTask>(this, true);
pending_foreground_task_ = new_task.get();
foreground_task_runner_->PostTask(std::move(new_task));
}
void AsyncCompileJob::ExecuteForegroundTaskImmediately() {
DCHECK_NULL(pending_foreground_task_);
auto new_task = base::make_unique<CompileTask>(this, true);
pending_foreground_task_ = new_task.get();
new_task->Run();
}
void AsyncCompileJob::CancelPendingForegroundTask() {
if (!pending_foreground_task_) return;
pending_foreground_task_->Cancel();
pending_foreground_task_ = nullptr;
}
void AsyncCompileJob::StartBackgroundTask() {
auto task = base::make_unique<CompileTask>(this, false);
// If --wasm-num-compilation-tasks=0 is passed, do only spawn foreground
// tasks. This is used to make timing deterministic.
if (FLAG_wasm_num_compilation_tasks > 0) {
V8::GetCurrentPlatform()->CallOnWorkerThread(std::move(task));
} else {
foreground_task_runner_->PostTask(std::move(task));
}
}
template <typename Step,
AsyncCompileJob::UseExistingForegroundTask use_existing_fg_task,
typename... Args>
void AsyncCompileJob::DoSync(Args&&... args) {
NextStep<Step>(std::forward<Args>(args)...);
if (use_existing_fg_task && pending_foreground_task_ != nullptr) return;
StartForegroundTask();
}
template <typename Step, typename... Args>
void AsyncCompileJob::DoImmediately(Args&&... args) {
NextStep<Step>(std::forward<Args>(args)...);
ExecuteForegroundTaskImmediately();
}
template <typename Step, typename... Args>
void AsyncCompileJob::DoAsync(Args&&... args) {
NextStep<Step>(std::forward<Args>(args)...);
StartBackgroundTask();
}
template <typename Step, typename... Args>
void AsyncCompileJob::NextStep(Args&&... args) {
step_.reset(new Step(std::forward<Args>(args)...));
}
//==========================================================================
// Step 1: (async) Decode the module.
//==========================================================================
class AsyncCompileJob::DecodeModule : public AsyncCompileJob::CompileStep {
public:
explicit DecodeModule(Counters* counters) : counters_(counters) {}
void RunInBackground(AsyncCompileJob* job) override {
ModuleResult result;
{
DisallowHandleAllocation no_handle;
DisallowHeapAllocation no_allocation;
// Decode the module bytes.
TRACE_COMPILE("(1) Decoding module...\n");
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"),
"AsyncCompileJob::DecodeModule");
result = DecodeWasmModule(
job->enabled_features_, job->wire_bytes_.start(),
job->wire_bytes_.end(), false, kWasmOrigin, counters_,
job->isolate()->wasm_engine()->allocator());
}
if (result.failed()) {
// Decoding failure; reject the promise and clean up.
job->DoSync<DecodeFail>(std::move(result));
} else {
// Decode passed.
job->DoSync<PrepareAndStartCompile>(std::move(result).value(), true);
}
}
private:
Counters* const counters_;
};
//==========================================================================
// Step 1b: (sync) Fail decoding the module.
//==========================================================================
class AsyncCompileJob::DecodeFail : public CompileStep {
public:
explicit DecodeFail(ModuleResult result) : result_(std::move(result)) {}
private:
ModuleResult result_;
void RunInForeground(AsyncCompileJob* job) override {
TRACE_COMPILE("(1b) Decoding failed.\n");
ErrorThrower thrower(job->isolate_, "AsyncCompile");
thrower.CompileFailed("Wasm decoding failed", result_);
// {job_} is deleted in AsyncCompileFailed, therefore the {return}.
return job->AsyncCompileFailed(thrower.Reify());
}
};
//==========================================================================
// Step 2 (sync): Create heap-allocated data and start compile.
//==========================================================================
class AsyncCompileJob::PrepareAndStartCompile : public CompileStep {
public:
PrepareAndStartCompile(std::shared_ptr<const WasmModule> module,
bool start_compilation)
: module_(std::move(module)), start_compilation_(start_compilation) {}
private:
std::shared_ptr<const WasmModule> module_;
bool start_compilation_;
void RunInForeground(AsyncCompileJob* job) override {
TRACE_COMPILE("(2) Prepare and start compile...\n");
// Make sure all compilation tasks stopped running. Decoding (async step)
// is done.
job->background_task_manager_.CancelAndWait();
job->CreateNativeModule(module_);
size_t num_functions =
module_->functions.size() - module_->num_imported_functions;
if (num_functions == 0) {
// Degenerate case of an empty module.
job->FinishCompile();
return;
}
CompilationStateImpl* compilation_state =
Impl(job->native_module_->compilation_state());
compilation_state->AddCallback(CompilationStateCallback{job});
if (start_compilation_) {
// TODO(ahaas): Try to remove the {start_compilation_} check when
// streaming decoding is done in the background. If
// InitializeCompilationUnits always returns 0 for streaming compilation,
// then DoAsync would do the same as NextStep already.
compilation_state->SetNumberOfFunctionsToCompile(
module_->num_declared_functions);
// Add compilation units and kick off compilation.
InitializeCompilationUnits(job->native_module_.get(),
job->isolate()->wasm_engine());
}
}
};
//==========================================================================
// Step 4b (sync): Compilation failed. Reject Promise.
//==========================================================================
class AsyncCompileJob::CompileFailed : public CompileStep {
public:
explicit CompileFailed(Handle<Object> error_reason)
: error_reason_(error_reason) {}
void RunInForeground(AsyncCompileJob* job) override {
TRACE_COMPILE("(4b) Compilation Failed...\n");
return job->AsyncCompileFailed(error_reason_);
}
private:
Handle<Object> error_reason_;
};
void AsyncCompileJob::CompileWrappers() {
// TODO(wasm): Compile all wrappers here, including the start function wrapper
// and the wrappers for the function table elements.
TRACE_COMPILE("(5) Compile wrappers...\n");
// Compile JS->wasm wrappers for exported functions.
CompileJsToWasmWrappers(isolate_, module_object_->native_module()->module(),
handle(module_object_->export_wrappers(), isolate_));
}
void AsyncCompileJob::FinishModule() {
TRACE_COMPILE("(6) Finish module...\n");
AsyncCompileSucceeded(module_object_);
size_t num_functions = native_module_->num_functions() -
native_module_->num_imported_functions();
auto* compilation_state = Impl(native_module_->compilation_state());
if (compilation_state->compile_mode() == CompileMode::kRegular ||
num_functions == 0) {
// If we do not tier up, the async compile job is done here and
// can be deleted.
isolate_->wasm_engine()->RemoveCompileJob(this);
return;
}
DCHECK_EQ(CompileMode::kTiering, compilation_state->compile_mode());
if (compilation_state->baseline_compilation_finished()) {
isolate_->wasm_engine()->RemoveCompileJob(this);
}
}
AsyncStreamingProcessor::AsyncStreamingProcessor(AsyncCompileJob* job)
: decoder_(job->enabled_features_),
job_(job),
compilation_unit_builder_(nullptr) {}
void AsyncStreamingProcessor::FinishAsyncCompileJobWithError(ResultBase error) {
DCHECK(error.failed());
// Make sure all background tasks stopped executing before we change the state
// of the AsyncCompileJob to DecodeFail.
job_->background_task_manager_.CancelAndWait();
// Create a ModuleResult from the result we got as parameter. Since there was
// an error, we don't have to provide a real wasm module to the ModuleResult.
ModuleResult result = ModuleResult::ErrorFrom(std::move(error));
// Check if there is already a CompiledModule, in which case we have to clean
// up the CompilationStateImpl as well.
if (job_->native_module_) {
Impl(job_->native_module_->compilation_state())->Abort();
job_->DoSync<AsyncCompileJob::DecodeFail,
AsyncCompileJob::kUseExistingForegroundTask>(
std::move(result));
// Clear the {compilation_unit_builder_} if it exists. This is needed
// because there is a check in the destructor of the
// {CompilationUnitBuilder} that it is empty.
if (compilation_unit_builder_) compilation_unit_builder_->Clear();
} else {
job_->DoSync<AsyncCompileJob::DecodeFail>(std::move(result));
}
}
// Process the module header.
bool AsyncStreamingProcessor::ProcessModuleHeader(Vector<const uint8_t> bytes,
uint32_t offset) {
TRACE_STREAMING("Process module header...\n");
decoder_.StartDecoding(job_->isolate()->counters(),
job_->isolate()->wasm_engine()->allocator());
decoder_.DecodeModuleHeader(bytes, offset);
if (!decoder_.ok()) {
FinishAsyncCompileJobWithError(decoder_.FinishDecoding(false));
return false;
}
return true;
}
// Process all sections except for the code section.
bool AsyncStreamingProcessor::ProcessSection(SectionCode section_code,
Vector<const uint8_t> bytes,
uint32_t offset) {
TRACE_STREAMING("Process section %d ...\n", section_code);
if (compilation_unit_builder_) {
// We reached a section after the code section, we do not need the
// compilation_unit_builder_ anymore.
CommitCompilationUnits();
compilation_unit_builder_.reset();
}
if (section_code == SectionCode::kUnknownSectionCode) {
Decoder decoder(bytes, offset);
section_code = ModuleDecoder::IdentifyUnknownSection(
decoder, bytes.start() + bytes.length());
if (section_code == SectionCode::kUnknownSectionCode) {
// Skip unknown sections that we do not know how to handle.
return true;
}
// Remove the unknown section tag from the payload bytes.
offset += decoder.position();
bytes = bytes.SubVector(decoder.position(), bytes.size());
}
constexpr bool verify_functions = false;
decoder_.DecodeSection(section_code, bytes, offset, verify_functions);
if (!decoder_.ok()) {
FinishAsyncCompileJobWithError(decoder_.FinishDecoding(false));
return false;
}
return true;
}
// Start the code section.
bool AsyncStreamingProcessor::ProcessCodeSectionHeader(
size_t functions_count, uint32_t offset,
std::shared_ptr<WireBytesStorage> wire_bytes_storage) {
TRACE_STREAMING("Start the code section with %zu functions...\n",
functions_count);
if (!decoder_.CheckFunctionsCount(static_cast<uint32_t>(functions_count),
offset)) {
FinishAsyncCompileJobWithError(decoder_.FinishDecoding(false));
return false;
}
// Execute the PrepareAndStartCompile step immediately and not in a separate
// task.
job_->DoImmediately<AsyncCompileJob::PrepareAndStartCompile>(
decoder_.shared_module(), false);
job_->native_module_->compilation_state()->SetWireBytesStorage(
std::move(wire_bytes_storage));
auto* compilation_state = Impl(job_->native_module_->compilation_state());
compilation_state->SetNumberOfFunctionsToCompile(functions_count);
// Set outstanding_finishers_ to 2, because both the AsyncCompileJob and the
// AsyncStreamingProcessor have to finish.
job_->outstanding_finishers_.store(2);
compilation_unit_builder_.reset(new CompilationUnitBuilder(
job_->native_module_.get(), job_->isolate()->wasm_engine()));
return true;
}
// Process a function body.
bool AsyncStreamingProcessor::ProcessFunctionBody(Vector<const uint8_t> bytes,
uint32_t offset) {
TRACE_STREAMING("Process function body %d ...\n", next_function_);
decoder_.DecodeFunctionBody(
next_function_, static_cast<uint32_t>(bytes.length()), offset, false);
uint32_t index = next_function_ + decoder_.module()->num_imported_functions;
compilation_unit_builder_->AddUnit(index);
++next_function_;
// This method always succeeds. The return value is necessary to comply with
// the StreamingProcessor interface.
return true;
}
void AsyncStreamingProcessor::CommitCompilationUnits() {
DCHECK(compilation_unit_builder_);
compilation_unit_builder_->Commit();
}
void AsyncStreamingProcessor::OnFinishedChunk() {
TRACE_STREAMING("FinishChunk...\n");
if (compilation_unit_builder_) CommitCompilationUnits();
}
// Finish the processing of the stream.
void AsyncStreamingProcessor::OnFinishedStream(OwnedVector<uint8_t> bytes) {
TRACE_STREAMING("Finish stream...\n");
ModuleResult result = decoder_.FinishDecoding(false);
if (result.failed()) {
FinishAsyncCompileJobWithError(std::move(result));
return;
}
// We have to open a HandleScope and prepare the Context for
// CreateNativeModule, PrepareRuntimeObjects and FinishCompile as this is a
// callback from the embedder.
HandleScope scope(job_->isolate_);
SaveContext saved_context(job_->isolate_);
job_->isolate_->set_context(*job_->native_context_);
bool needs_finish = job_->DecrementAndCheckFinisherCount();
if (job_->native_module_ == nullptr) {
// We are processing a WebAssembly module without code section. Create the
// runtime objects now (would otherwise happen in {PrepareAndStartCompile}).
job_->CreateNativeModule(std::move(result).value());
DCHECK(needs_finish);
}
job_->wire_bytes_ = ModuleWireBytes(bytes.as_vector());
job_->native_module_->SetWireBytes(std::move(bytes));
if (needs_finish) {
job_->FinishCompile();
}
}
// Report an error detected in the StreamingDecoder.
void AsyncStreamingProcessor::OnError(DecodeResult result) {
TRACE_STREAMING("Stream error...\n");
FinishAsyncCompileJobWithError(std::move(result));
}
void AsyncStreamingProcessor::OnAbort() {
TRACE_STREAMING("Abort stream...\n");
job_->Abort();
}
bool AsyncStreamingProcessor::Deserialize(Vector<const uint8_t> module_bytes,
Vector<const uint8_t> wire_bytes) {
// DeserializeNativeModule and FinishCompile assume that they are executed in
// a HandleScope, and that a context is set on the isolate.
HandleScope scope(job_->isolate_);
SaveContext saved_context(job_->isolate_);
job_->isolate_->set_context(*job_->native_context_);
MaybeHandle<WasmModuleObject> result =
DeserializeNativeModule(job_->isolate_, module_bytes, wire_bytes);
if (result.is_null()) return false;
job_->module_object_ = result.ToHandleChecked();
{
DeferredHandleScope deferred(job_->isolate_);
job_->module_object_ = handle(*job_->module_object_, job_->isolate_);
job_->deferred_handles_.push_back(deferred.Detach());
}
job_->native_module_ = job_->module_object_->shared_native_module();
auto owned_wire_bytes = OwnedVector<uint8_t>::Of(wire_bytes);
job_->wire_bytes_ = ModuleWireBytes(owned_wire_bytes.as_vector());
job_->native_module_->SetWireBytes(std::move(owned_wire_bytes));
job_->FinishCompile();
return true;
}
CompilationStateImpl::CompilationStateImpl(internal::Isolate* isolate,
NativeModule* native_module)
: isolate_(isolate),
native_module_(native_module),
compile_mode_(FLAG_wasm_tier_up &&
native_module->module()->origin == kWasmOrigin
? CompileMode::kTiering
: CompileMode::kRegular),
should_log_code_(WasmCode::ShouldBeLogged(isolate)),
max_background_tasks_(std::max(
1, std::min(FLAG_wasm_num_compilation_tasks,
V8::GetCurrentPlatform()->NumberOfWorkerThreads()))) {
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate_);
v8::Platform* platform = V8::GetCurrentPlatform();
foreground_task_runner_ = platform->GetForegroundTaskRunner(v8_isolate);
}
CompilationStateImpl::~CompilationStateImpl() {
DCHECK(background_task_manager_.canceled());
DCHECK(foreground_task_manager_.canceled());
CompilationError* error = compile_error_.load(std::memory_order_acquire);
if (error != nullptr) delete error;
}
void CompilationStateImpl::CancelAndWait() {
background_task_manager_.CancelAndWait();
foreground_task_manager_.CancelAndWait();
}
void CompilationStateImpl::SetNumberOfFunctionsToCompile(size_t num_functions) {
DCHECK(!failed());
base::MutexGuard guard(&mutex_);
outstanding_baseline_units_ = num_functions;
if (compile_mode_ == CompileMode::kTiering) {
outstanding_tiering_units_ = num_functions;
}
}
void CompilationStateImpl::AddCallback(CompilationState::callback_t callback) {
callbacks_.emplace_back(std::move(callback));
}
void CompilationStateImpl::AddCompilationUnits(
std::vector<std::unique_ptr<WasmCompilationUnit>>& baseline_units,
std::vector<std::unique_ptr<WasmCompilationUnit>>& tiering_units) {
{
base::MutexGuard guard(&mutex_);
if (compile_mode_ == CompileMode::kTiering) {
DCHECK_EQ(baseline_units.size(), tiering_units.size());
DCHECK_EQ(tiering_units.back()->tier(), ExecutionTier::kOptimized);
tiering_compilation_units_.insert(
tiering_compilation_units_.end(),
std::make_move_iterator(tiering_units.begin()),
std::make_move_iterator(tiering_units.end()));
} else {
DCHECK(tiering_compilation_units_.empty());
}
baseline_compilation_units_.insert(
baseline_compilation_units_.end(),
std::make_move_iterator(baseline_units.begin()),
std::make_move_iterator(baseline_units.end()));
}
RestartBackgroundTasks();
}
std::unique_ptr<WasmCompilationUnit>
CompilationStateImpl::GetNextCompilationUnit() {
base::MutexGuard guard(&mutex_);
std::vector<std::unique_ptr<WasmCompilationUnit>>& units =
baseline_compilation_units_.empty() ? tiering_compilation_units_
: baseline_compilation_units_;
if (!units.empty()) {
std::unique_ptr<WasmCompilationUnit> unit = std::move(units.back());
units.pop_back();
return unit;
}
return std::unique_ptr<WasmCompilationUnit>();
}
std::unique_ptr<WasmCompilationUnit>
CompilationStateImpl::GetNextExecutedUnit() {
std::vector<std::unique_ptr<WasmCompilationUnit>>& units = finish_units();
base::MutexGuard guard(&mutex_);
if (units.empty()) return {};
std::unique_ptr<WasmCompilationUnit> ret = std::move(units.back());
units.pop_back();
return ret;
}
bool CompilationStateImpl::HasCompilationUnitToFinish() {
return !finish_units().empty();
}
void CompilationStateImpl::OnFinishedUnit(ExecutionTier tier) {
// This mutex guarantees that events happen in the right order.
base::MutexGuard guard(&mutex_);
if (failed()) return;
// If we are *not* compiling in tiering mode, then all units are counted as
// baseline units.
bool is_tiering_mode = compile_mode_ == CompileMode::kTiering;
bool is_tiering_unit = is_tiering_mode && tier == ExecutionTier::kOptimized;
// Sanity check: If we are not in tiering mode, there cannot be outstanding
// tiering units.
DCHECK_IMPLIES(!is_tiering_mode, outstanding_tiering_units_ == 0);
// Bitset of events to deliver.
EnumSet<CompilationEvent> events;
if (is_tiering_unit) {
DCHECK_LT(0, outstanding_tiering_units_);
--outstanding_tiering_units_;
if (outstanding_tiering_units_ == 0) {
// If baseline compilation has not finished yet, then also trigger
// {kFinishedBaselineCompilation}.
if (outstanding_baseline_units_ > 0) {
events.Add(CompilationEvent::kFinishedBaselineCompilation);
}
events.Add(CompilationEvent::kFinishedTopTierCompilation);
}
} else {
DCHECK_LT(0, outstanding_baseline_units_);
--outstanding_baseline_units_;
if (outstanding_baseline_units_ == 0) {
events.Add(CompilationEvent::kFinishedBaselineCompilation);
// If we are not tiering, then we also trigger the "top tier finished"
// event when baseline compilation is finished.
if (!is_tiering_mode) {
events.Add(CompilationEvent::kFinishedTopTierCompilation);
}
}
}
if (!events.IsEmpty()) {
auto notify_events = [this, events] {
for (auto event : {CompilationEvent::kFinishedBaselineCompilation,
CompilationEvent::kFinishedTopTierCompilation}) {
if (!events.Contains(event)) continue;
NotifyOnEvent(event, nullptr);
}
};
foreground_task_runner_->PostTask(
MakeCancelableTask(&foreground_task_manager_, notify_events));
}
}
void CompilationStateImpl::ScheduleCodeLogging(WasmCode* code) {
if (!should_log_code_) return;
base::MutexGuard guard(&mutex_);
if (log_codes_task_ == nullptr) {
auto new_task = base::make_unique<LogCodesTask>(&foreground_task_manager_,
this, isolate_);
log_codes_task_ = new_task.get();
foreground_task_runner_->PostTask(std::move(new_task));
}
log_codes_task_->AddCode(code);
}
void CompilationStateImpl::OnBackgroundTaskStopped(
const WasmFeatures& detected) {
base::MutexGuard guard(&mutex_);
DCHECK_LE(1, num_background_tasks_);
--num_background_tasks_;
UnionFeaturesInto(&detected_features_, detected);
}
void CompilationStateImpl::PublishDetectedFeatures(
Isolate* isolate, const WasmFeatures& detected) {
// Notifying the isolate of the feature counts must take place under
// the mutex, because even if we have finished baseline compilation,
// tiering compilations may still occur in the background.
base::MutexGuard guard(&mutex_);
UnionFeaturesInto(&detected_features_, detected);
UpdateFeatureUseCounts(isolate, detected_features_);
}
void CompilationStateImpl::RestartBackgroundTasks(size_t max) {
size_t num_restart;
{
base::MutexGuard guard(&mutex_);
// No need to restart tasks if compilation already failed.
if (failed()) return;
DCHECK_LE(num_background_tasks_, max_background_tasks_);
if (num_background_tasks_ == max_background_tasks_) return;
size_t num_compilation_units =
baseline_compilation_units_.size() + tiering_compilation_units_.size();
size_t stopped_tasks = max_background_tasks_ - num_background_tasks_;
num_restart = std::min(max, std::min(num_compilation_units, stopped_tasks));
num_background_tasks_ += num_restart;
}
for (; num_restart > 0; --num_restart) {
auto task = base::make_unique<BackgroundCompileTask>(
&background_task_manager_, native_module_, isolate_->counters());
// If --wasm-num-compilation-tasks=0 is passed, do only spawn foreground
// tasks. This is used to make timing deterministic.
if (FLAG_wasm_num_compilation_tasks > 0) {
V8::GetCurrentPlatform()->CallOnWorkerThread(std::move(task));
} else {
foreground_task_runner_->PostTask(std::move(task));
}
}
}
bool CompilationStateImpl::SetFinisherIsRunning(bool value) {
base::MutexGuard guard(&mutex_);
if (finisher_is_running_ == value) return false;
finisher_is_running_ = value;
return true;
}
void CompilationStateImpl::ScheduleFinisherTask() {
foreground_task_runner_->PostTask(
base::make_unique<FinishCompileTask>(this, &foreground_task_manager_));
}
void CompilationStateImpl::Abort() {
SetError(0, VoidResult::Error(0, "Compilation aborted"));
background_task_manager_.CancelAndWait();
// No more callbacks after abort. Don't free the std::function objects here,
// since this might clear references in the embedder, which is only allowed on
// the main thread.
aborted_.store(true);
if (!callbacks_.empty()) {
foreground_task_runner_->PostTask(
base::make_unique<FreeCallbacksTask>(this));
}
}
void CompilationStateImpl::SetError(uint32_t func_index,
const ResultBase& error_result) {
DCHECK(error_result.failed());
std::unique_ptr<CompilationError> error =
base::make_unique<CompilationError>(func_index, error_result);
CompilationError* expected = nullptr;
bool set = compile_error_.compare_exchange_strong(expected, error.get(),
std::memory_order_acq_rel);
// Ignore all but the first error. If the previous value is not nullptr, just
// return (and free the allocated error).
if (!set) return;
// If set successfully, give up ownership.
error.release();
// Schedule a foreground task to call the callback and notify users about the
// compile error.
foreground_task_runner_->PostTask(
MakeCancelableTask(&foreground_task_manager_, [this] {
VoidResult error_result = GetCompileError();
NotifyOnEvent(CompilationEvent::kFailedCompilation, &error_result);
}));
}
void CompilationStateImpl::NotifyOnEvent(CompilationEvent event,
const VoidResult* error_result) {
if (aborted_.load()) return;
HandleScope scope(isolate_);
for (auto& callback : callbacks_) callback(event, error_result);
// If no more events are expected after this one, clear the callbacks to free
// memory. We can safely do this here, as this method is only called from
// foreground tasks.
if (event >= CompilationEvent::kFirstFinalEvent) callbacks_.clear();
}
void CompileJsToWasmWrappers(Isolate* isolate, const WasmModule* module,
Handle<FixedArray> export_wrappers) {
JSToWasmWrapperCache js_to_wasm_cache;
int wrapper_index = 0;
// TODO(6792): Wrappers below are allocated with {Factory::NewCode}. As an
// optimization we keep the code space unlocked to avoid repeated unlocking
// because many such wrapper are allocated in sequence below.
CodeSpaceMemoryModificationScope modification_scope(isolate->heap());
for (auto exp : module->export_table) {
if (exp.kind != kExternalFunction) continue;
auto& function = module->functions[exp.index];
Handle<Code> wrapper_code = js_to_wasm_cache.GetOrCompileJSToWasmWrapper(
isolate, function.sig, function.imported);
export_wrappers->set(wrapper_index, *wrapper_code);
RecordStats(*wrapper_code, isolate->counters());
++wrapper_index;
}
}
Handle<Script> CreateWasmScript(Isolate* isolate,
const ModuleWireBytes& wire_bytes,
const std::string& source_map_url) {
Handle<Script> script =
isolate->factory()->NewScript(isolate->factory()->empty_string());
script->set_context_data(isolate->native_context()->debug_context_id());
script->set_type(Script::TYPE_WASM);
int hash = StringHasher::HashSequentialString(
reinterpret_cast<const char*>(wire_bytes.start()),
static_cast<int>(wire_bytes.length()), kZeroHashSeed);
const int kBufferSize = 32;
char buffer[kBufferSize];
int name_chars = SNPrintF(ArrayVector(buffer), "wasm-%08x", hash);
DCHECK(name_chars >= 0 && name_chars < kBufferSize);
MaybeHandle<String> name_str = isolate->factory()->NewStringFromOneByte(
VectorOf(reinterpret_cast<uint8_t*>(buffer), name_chars), TENURED);
script->set_name(*name_str.ToHandleChecked());
if (source_map_url.size() != 0) {
MaybeHandle<String> src_map_str = isolate->factory()->NewStringFromUtf8(
CStrVector(source_map_url.c_str()), TENURED);
script->set_source_mapping_url(*src_map_str.ToHandleChecked());
}
return script;
}
} // namespace wasm
} // namespace internal
} // namespace v8
#undef TRACE
#undef TRACE_COMPILE
#undef TRACE_STREAMING
#undef TRACE_LAZY