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Merged
merged 2 commits into from
Feb 23, 2024
Merged

src: simplify embedder entry point execution. #51557

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4a6c71e
src: simplify embedder entry point execution
joyeecheung Jan 24, 2024
12a88cf
fixup! src: simplify embedder entry point execution
joyeecheung Feb 16, 2024
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5 changes: 1 addition & 4 deletions lib/internal/main/embedding.js
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Original file line number Diff line number Diff line change
@@ -1,18 +1,15 @@
'use strict';
const {
prepareMainThreadExecution,
markBootstrapComplete,
} = require('internal/process/pre_execution');
const { isExperimentalSeaWarningNeeded } = internalBinding('sea');
const { emitExperimentalWarning } = require('internal/util');
const { embedderRequire, embedderRunCjs } = require('internal/util/embedding');
const { runEmbedderEntryPoint } = internalBinding('mksnapshot');

prepareMainThreadExecution(false, true);
markBootstrapComplete();

if (isExperimentalSeaWarningNeeded()) {
emitExperimentalWarning('Single executable application');
}

return runEmbedderEntryPoint(process, embedderRequire, embedderRunCjs);
return [process, embedderRequire, embedderRunCjs];
15 changes: 2 additions & 13 deletions lib/internal/main/mksnapshot.js
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,6 @@ const {

const { BuiltinModule: { normalizeRequirableId } } = require('internal/bootstrap/realm');
const {
runEmbedderEntryPoint,
compileSerializeMain,
anonymousMainPath,
} = internalBinding('mksnapshot');
Expand All @@ -20,9 +19,6 @@ const { isExperimentalSeaWarningNeeded } = internalBinding('sea');

const { emitExperimentalWarning } = require('internal/util');
const { emitWarningSync } = require('internal/process/warning');
const {
getOptionValue,
} = require('internal/options');

const {
initializeCallbacks,
Expand Down Expand Up @@ -179,18 +175,11 @@ function main() {
return fn(requireForUserSnapshot, filename, dirname);
}

const serializeMainArgs = [process, requireForUserSnapshot, minimalRunCjs];

if (isExperimentalSeaWarningNeeded()) {
emitExperimentalWarning('Single executable application');
}

if (getOptionValue('--inspect-brk')) {
internalBinding('inspector').callAndPauseOnStart(
runEmbedderEntryPoint, undefined, ...serializeMainArgs);
} else {
runEmbedderEntryPoint(...serializeMainArgs);
}
return [process, requireForUserSnapshot, minimalRunCjs];
}

main();
return main();
8 changes: 0 additions & 8 deletions src/env-inl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -430,14 +430,6 @@ inline builtins::BuiltinLoader* Environment::builtin_loader() {
return &builtin_loader_;
}

inline const StartExecutionCallback& Environment::embedder_entry_point() const {
return embedder_entry_point_;
}

inline void Environment::set_embedder_entry_point(StartExecutionCallback&& fn) {
embedder_entry_point_ = std::move(fn);
}

inline double Environment::new_async_id() {
async_hooks()->async_id_fields()[AsyncHooks::kAsyncIdCounter] += 1;
return async_hooks()->async_id_fields()[AsyncHooks::kAsyncIdCounter];
Expand Down
4 changes: 0 additions & 4 deletions src/env.h
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Expand Up @@ -999,9 +999,6 @@ class Environment : public MemoryRetainer {

#endif // HAVE_INSPECTOR

inline const StartExecutionCallback& embedder_entry_point() const;
inline void set_embedder_entry_point(StartExecutionCallback&& fn);

inline void set_process_exit_handler(
std::function<void(Environment*, ExitCode)>&& handler);

Expand Down Expand Up @@ -1207,7 +1204,6 @@ class Environment : public MemoryRetainer {
std::unique_ptr<PrincipalRealm> principal_realm_ = nullptr;

builtins::BuiltinLoader builtin_loader_;
StartExecutionCallback embedder_entry_point_;

// Used by allocate_managed_buffer() and release_managed_buffer() to keep
// track of the BackingStore for a given pointer.
Expand Down
60 changes: 51 additions & 9 deletions src/node.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -131,7 +131,10 @@

namespace node {

using v8::Array;
using v8::Context;
using v8::EscapableHandleScope;
using v8::Function;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
Expand Down Expand Up @@ -282,26 +285,65 @@ MaybeLocal<Value> StartExecution(Environment* env, const char* main_script_id) {
return scope.EscapeMaybe(realm->ExecuteBootstrapper(main_script_id));
}

// Convert the result returned by an intermediate main script into
// StartExecutionCallbackInfo. Currently the result is an array containing
// [process, requireFunction, cjsRunner]
std::optional<StartExecutionCallbackInfo> CallbackInfoFromArray(
Local<Context> context, Local<Value> result) {
CHECK(result->IsArray());
Local<Array> args = result.As<Array>();
CHECK_EQ(args->Length(), 3);
Local<Value> process_obj, require_fn, runcjs_fn;
if (!args->Get(context, 0).ToLocal(&process_obj) ||
!args->Get(context, 1).ToLocal(&require_fn) ||
!args->Get(context, 2).ToLocal(&runcjs_fn)) {
return std::nullopt;
}
CHECK(process_obj->IsObject());
CHECK(require_fn->IsFunction());
CHECK(runcjs_fn->IsFunction());
node::StartExecutionCallbackInfo info{process_obj.As<Object>(),
require_fn.As<Function>(),
runcjs_fn.As<Function>()};
return info;
}

MaybeLocal<Value> StartExecution(Environment* env, StartExecutionCallback cb) {
InternalCallbackScope callback_scope(
env,
Object::New(env->isolate()),
{ 1, 0 },
InternalCallbackScope::kSkipAsyncHooks);

// Only snapshot builder or embedder applications set the
// callback.
if (cb != nullptr) {
EscapableHandleScope scope(env->isolate());
// TODO(addaleax): pass the callback to the main script more directly,
// e.g. by making StartExecution(env, builtin) parametrizable
env->set_embedder_entry_point(std::move(cb));
auto reset_entry_point =
OnScopeLeave([&]() { env->set_embedder_entry_point({}); });

const char* entry = env->isolate_data()->is_building_snapshot()
? "internal/main/mksnapshot"
: "internal/main/embedding";
Local<Value> result;
if (env->isolate_data()->is_building_snapshot()) {
if (!StartExecution(env, "internal/main/mksnapshot").ToLocal(&result)) {
return MaybeLocal<Value>();
}
} else {
if (!StartExecution(env, "internal/main/embedding").ToLocal(&result)) {
return MaybeLocal<Value>();
}
}

auto info = CallbackInfoFromArray(env->context(), result);
if (!info.has_value()) {
MaybeLocal<Value>();
}
#if HAVE_INSPECTOR
if (env->options()->debug_options().break_first_line) {
env->inspector_agent()->PauseOnNextJavascriptStatement("Break on start");
}
#endif

return scope.EscapeMaybe(StartExecution(env, entry));
env->performance_state()->Mark(
performance::NODE_PERFORMANCE_MILESTONE_BOOTSTRAP_COMPLETE);
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I think this can still be marked in JS with markBootstrapComplete, similar to other entry points.

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@joyeecheung joyeecheung Feb 21, 2024 •
edited
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The other entry points don't take callbacks. I think it's less convoluted to mark this right before we invoke the callback, otherwise it's quite difficult to wrap your head around things going back and forth between C++ and JS for these entry points that take callbacks (that's what I feel whenever I looked at these two, and I even reviewed the original changes).

return scope.EscapeMaybe(cb(info.value()));
}

CHECK(!env->isolate_data()->is_building_snapshot());
Expand Down
22 changes: 0 additions & 22 deletions src/node_snapshotable.cc
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Expand Up @@ -40,7 +40,6 @@ using v8::FunctionCallbackInfo;
using v8::HandleScope;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::Object;
using v8::ObjectTemplate;
using v8::ScriptCompiler;
Expand Down Expand Up @@ -1434,25 +1433,6 @@ void SerializeSnapshotableObjects(Realm* realm,
});
}

static void RunEmbedderEntryPoint(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
Local<Value> process_obj = args[0];
Local<Value> require_fn = args[1];
Local<Value> runcjs_fn = args[2];
CHECK(process_obj->IsObject());
CHECK(require_fn->IsFunction());
CHECK(runcjs_fn->IsFunction());

const node::StartExecutionCallback& callback = env->embedder_entry_point();
node::StartExecutionCallbackInfo info{process_obj.As<Object>(),
require_fn.As<Function>(),
runcjs_fn.As<Function>()};
MaybeLocal<Value> retval = callback(info);
if (!retval.IsEmpty()) {
args.GetReturnValue().Set(retval.ToLocalChecked());
}
}

void CompileSerializeMain(const FunctionCallbackInfo<Value>& args) {
CHECK(args[0]->IsString());
Local<String> filename = args[0].As<String>();
Expand Down Expand Up @@ -1576,7 +1556,6 @@ void CreatePerContextProperties(Local<Object> target,
void CreatePerIsolateProperties(IsolateData* isolate_data,
Local<ObjectTemplate> target) {
Isolate* isolate = isolate_data->isolate();
SetMethod(isolate, target, "runEmbedderEntryPoint", RunEmbedderEntryPoint);
SetMethod(isolate, target, "compileSerializeMain", CompileSerializeMain);
SetMethod(isolate, target, "setSerializeCallback", SetSerializeCallback);
SetMethod(isolate, target, "setDeserializeCallback", SetDeserializeCallback);
Expand All @@ -1589,7 +1568,6 @@ void CreatePerIsolateProperties(IsolateData* isolate_data,
}

void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
registry->Register(RunEmbedderEntryPoint);
registry->Register(CompileSerializeMain);
registry->Register(SetSerializeCallback);
registry->Register(SetDeserializeCallback);
Expand Down