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// 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.
#ifndef V8_WASM_WASM_ENGINE_H_
#define V8_WASM_WASM_ENGINE_H_
#include <memory>
#include <unordered_set>
#include "src/cancelable-task.h"
#include "src/wasm/wasm-code-manager.h"
#include "src/wasm/wasm-memory.h"
#include "src/wasm/wasm-tier.h"
#include "src/zone/accounting-allocator.h"
namespace v8 {
namespace internal {
class AsmWasmData;
class CodeTracer;
class CompilationStatistics;
class HeapNumber;
class WasmInstanceObject;
class WasmModuleObject;
namespace wasm {
class AsyncCompileJob;
class ErrorThrower;
struct ModuleWireBytes;
struct WasmFeatures;
class V8_EXPORT_PRIVATE CompilationResultResolver {
public:
virtual void OnCompilationSucceeded(Handle<WasmModuleObject> result) = 0;
virtual void OnCompilationFailed(Handle<Object> error_reason) = 0;
virtual ~CompilationResultResolver() = default;
};
class V8_EXPORT_PRIVATE InstantiationResultResolver {
public:
virtual void OnInstantiationSucceeded(Handle<WasmInstanceObject> result) = 0;
virtual void OnInstantiationFailed(Handle<Object> error_reason) = 0;
virtual ~InstantiationResultResolver() = default;
};
// The central data structure that represents an engine instance capable of
// loading, instantiating, and executing WASM code.
class V8_EXPORT_PRIVATE WasmEngine {
public:
WasmEngine();
~WasmEngine();
// Synchronously validates the given bytes that represent an encoded WASM
// module.
bool SyncValidate(Isolate* isolate, const WasmFeatures& enabled,
const ModuleWireBytes& bytes);
// Synchronously compiles the given bytes that represent a translated
// asm.js module.
MaybeHandle<AsmWasmData> SyncCompileTranslatedAsmJs(
Isolate* isolate, ErrorThrower* thrower, const ModuleWireBytes& bytes,
Vector<const byte> asm_js_offset_table_bytes,
Handle<HeapNumber> uses_bitset);
Handle<WasmModuleObject> FinalizeTranslatedAsmJs(
Isolate* isolate, Handle<AsmWasmData> asm_wasm_data,
Handle<Script> script);
// Synchronously compiles the given bytes that represent an encoded WASM
// module.
MaybeHandle<WasmModuleObject> SyncCompile(Isolate* isolate,
const WasmFeatures& enabled,
ErrorThrower* thrower,
const ModuleWireBytes& bytes);
// Synchronously instantiate the given WASM module with the given imports.
// If the module represents an asm.js module, then the supplied {memory}
// should be used as the memory of the instance.
MaybeHandle<WasmInstanceObject> SyncInstantiate(
Isolate* isolate, ErrorThrower* thrower,
Handle<WasmModuleObject> module_object, MaybeHandle<JSReceiver> imports,
MaybeHandle<JSArrayBuffer> memory);
// Begin an asynchronous compilation of the given bytes that represent an
// encoded WASM module.
// The {is_shared} flag indicates if the bytes backing the module could
// be shared across threads, i.e. could be concurrently modified.
void AsyncCompile(Isolate* isolate, const WasmFeatures& enabled,
std::shared_ptr<CompilationResultResolver> resolver,
const ModuleWireBytes& bytes, bool is_shared);
// Begin an asynchronous instantiation of the given WASM module.
void AsyncInstantiate(Isolate* isolate,
std::unique_ptr<InstantiationResultResolver> resolver,
Handle<WasmModuleObject> module_object,
MaybeHandle<JSReceiver> imports);
std::shared_ptr<StreamingDecoder> StartStreamingCompilation(
Isolate* isolate, const WasmFeatures& enabled, Handle<Context> context,
const char* api_method_name,
std::shared_ptr<CompilationResultResolver> resolver);
// Compiles the function with the given index at a specific compilation tier.
// Errors are stored internally in the CompilationState.
// This is mostly used for testing to force a function into a specific tier.
void CompileFunction(Isolate* isolate, NativeModule* native_module,
uint32_t function_index, ExecutionTier tier);
// Exports the sharable parts of the given module object so that they can be
// transferred to a different Context/Isolate using the same engine.
std::shared_ptr<NativeModule> ExportNativeModule(
Handle<WasmModuleObject> module_object);
// Imports the shared part of a module from a different Context/Isolate using
// the the same engine, recreating a full module object in the given Isolate.
Handle<WasmModuleObject> ImportNativeModule(
Isolate* isolate, std::shared_ptr<NativeModule> shared_module);
WasmCodeManager* code_manager() { return &code_manager_; }
WasmMemoryTracker* memory_tracker() { return &memory_tracker_; }
AccountingAllocator* allocator() { return &allocator_; }
// Compilation statistics for TurboFan compilations.
CompilationStatistics* GetOrCreateTurboStatistics();
// Prints the gathered compilation statistics, then resets them.
void DumpAndResetTurboStatistics();
// Used to redirect tracing output from {stdout} to a file.
CodeTracer* GetCodeTracer();
// Remove {job} from the list of active compile jobs.
std::unique_ptr<AsyncCompileJob> RemoveCompileJob(AsyncCompileJob* job);
// Returns true if at least one AsyncCompileJob that belongs to the given
// Isolate is currently running.
bool HasRunningCompileJob(Isolate* isolate);
// Deletes all AsyncCompileJobs that belong to the given Isolate. All
// compilation is aborted, no more callbacks will be triggered. This is used
// for tearing down an isolate, or to clean it up to be reused.
void DeleteCompileJobsOnIsolate(Isolate* isolate);
// Manage the set of Isolates that use this WasmEngine.
void AddIsolate(Isolate* isolate);
void RemoveIsolate(Isolate* isolate);
template <typename T, typename... Args>
std::unique_ptr<T> NewBackgroundCompileTask(Args&&... args) {
return base::make_unique<T>(&background_compile_task_manager_,
std::forward<Args>(args)...);
}
// Trigger code logging for this WasmCode in all Isolates which have access to
// the NativeModule containing this code. This method can be called from
// background threads.
void LogCode(WasmCode*);
// Enable code logging for the given Isolate. Initially, code logging is
// enabled if {WasmCode::ShouldBeLogged(Isolate*)} returns true during
// {AddIsolate}.
void EnableCodeLogging(Isolate*);
// This is called from the foreground thread of the Isolate to log all
// outstanding code objects (added via {LogCode}).
void LogOutstandingCodesForIsolate(Isolate*);
// Create a new NativeModule. The caller is responsible for its
// lifetime. The native module will be given some memory for code,
// which will be page size aligned. The size of the initial memory
// is determined with a heuristic based on the total size of wasm
// code. The native module may later request more memory.
// TODO(titzer): isolate is only required here for CompilationState.
std::shared_ptr<NativeModule> NewNativeModule(
Isolate* isolate, const WasmFeatures& enabled_features,
size_t code_size_estimate, bool can_request_more,
std::shared_ptr<const WasmModule> module);
void FreeNativeModule(NativeModule*);
// Sample the code size of the given {NativeModule} in all isolates that have
// access to it. Call this after top-tier compilation finished.
// This will spawn foreground tasks that do *not* keep the NativeModule alive.
void SampleTopTierCodeSizeInAllIsolates(const std::shared_ptr<NativeModule>&);
// Called by each Isolate to report its live code for a GC cycle. First
// version reports an externally determined set of live code (might be empty),
// second version gets live code from the execution stack of that isolate.
void ReportLiveCodeForGC(Isolate*, Vector<WasmCode*>);
void ReportLiveCodeFromStackForGC(Isolate*);
// Add potentially dead code. The occurrence in the set of potentially dead
// code counts as a reference, and is decremented on the next GC.
// Returns {true} if the code was added to the set of potentially dead code,
// {false} if an entry already exists. The ref count is *unchanged* in any
// case.
V8_WARN_UNUSED_RESULT bool AddPotentiallyDeadCode(WasmCode*);
// Free dead code.
using DeadCodeMap = std::unordered_map<NativeModule*, std::vector<WasmCode*>>;
void FreeDeadCode(const DeadCodeMap&);
void FreeDeadCodeLocked(const DeadCodeMap&);
// Call on process start and exit.
static void InitializeOncePerProcess();
static void GlobalTearDown();
// Constructs a WasmEngine instance. Depending on whether we are sharing
// engines this might be a pointer to a new instance or to a shared one.
static std::shared_ptr<WasmEngine> GetWasmEngine();
private:
struct CurrentGCInfo;
struct IsolateInfo;
struct NativeModuleInfo;
AsyncCompileJob* CreateAsyncCompileJob(
Isolate* isolate, const WasmFeatures& enabled,
std::unique_ptr<byte[]> bytes_copy, size_t length,
Handle<Context> context, const char* api_method_name,
std::shared_ptr<CompilationResultResolver> resolver);
void TriggerGC(int8_t gc_sequence_index);
// Remove an isolate from the outstanding isolates of the current GC. Returns
// true if the isolate was still outstanding, false otherwise. Hold {mutex_}
// when calling this method.
bool RemoveIsolateFromCurrentGC(Isolate*);
// Finish a GC if there are no more outstanding isolates. Hold {mutex_} when
// calling this method.
void PotentiallyFinishCurrentGC();
WasmMemoryTracker memory_tracker_;
WasmCodeManager code_manager_;
AccountingAllocator allocator_;
// Task manager managing all background compile jobs. Before shut down of the
// engine, they must all be finished because they access the allocator.
CancelableTaskManager background_compile_task_manager_;
// This mutex protects all information which is mutated concurrently or
// fields that are initialized lazily on the first access.
base::Mutex mutex_;
//////////////////////////////////////////////////////////////////////////////
// Protected by {mutex_}:
// We use an AsyncCompileJob as the key for itself so that we can delete the
// job from the map when it is finished.
std::unordered_map<AsyncCompileJob*, std::unique_ptr<AsyncCompileJob>>
async_compile_jobs_;
std::unique_ptr<CompilationStatistics> compilation_stats_;
std::unique_ptr<CodeTracer> code_tracer_;
// Set of isolates which use this WasmEngine.
std::unordered_map<Isolate*, std::unique_ptr<IsolateInfo>> isolates_;
// Set of native modules managed by this engine.
std::unordered_map<NativeModule*, std::unique_ptr<NativeModuleInfo>>
native_modules_;
// Size of code that became dead since the last GC. If this exceeds a certain
// threshold, a new GC is triggered.
size_t new_potentially_dead_code_size_ = 0;
// If an engine-wide GC is currently running, this pointer stores information
// about that.
std::unique_ptr<CurrentGCInfo> current_gc_info_;
// End of fields protected by {mutex_}.
//////////////////////////////////////////////////////////////////////////////
DISALLOW_COPY_AND_ASSIGN(WasmEngine);
};
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_WASM_ENGINE_H_