vm,trace_events: add node.vm.script trace events category

Add basic trace events for node_contextify. These generally
align very well with V8.ScriptCompile and V8.ScriptExecute
trace events and provide good additional context. For instance,
using the node.vm.script trace category at startup allows us to
see exactly how long compilation and init of each of our core
modules adds to the startup time.

PR-URL: #20728
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: jasnell

doc/api/tracing.md

@@ -24,6 +24,8 @@ The available categories are:
   * `node.perf.timerify` - Enables capture of only Performance API timerify
     measurements.
 * `node.fs.sync` - Enables capture of trace data for file system sync methods.
+* `node.vm.script` - Enables capture of trace data for the `vm` module's
+  `runInNewContext()`, `runInContext()`, and `runInThisContext()` methods.
 * `v8` - The [V8] events are GC, compiling, and execution related.
 
 By default the `node`, `node.async_hooks`, and `v8` categories are enabled.

src/node_contextify.cc

@@ -665,6 +665,16 @@ class ContextifyScript : public BaseObject {
     ContextifyScript* contextify_script =
         new ContextifyScript(env, args.This());
 
+    if (*TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
+            TRACING_CATEGORY_NODE2(vm, script)) != 0) {
+      Utf8Value fn(isolate, filename);
+      TRACE_EVENT_NESTABLE_ASYNC_BEGIN1(
+          TRACING_CATEGORY_NODE2(vm, script),
+          "ContextifyScript::New",
+          contextify_script,
+          "filename", TRACE_STR_COPY(*fn));
+    }
+
     ScriptCompiler::CachedData* cached_data = nullptr;
     if (!cached_data_buf.IsEmpty()) {
       ArrayBuffer::Contents contents = cached_data_buf->Buffer()->GetContents();
@@ -694,6 +704,10 @@ class ContextifyScript : public BaseObject {
       DecorateErrorStack(env, try_catch);
       no_abort_scope.Close();
       try_catch.ReThrow();
+      TRACE_EVENT_NESTABLE_ASYNC_END0(
+          TRACING_CATEGORY_NODE2(vm, script),
+          "ContextifyScript::New",
+          contextify_script);
       return;
     }
     contextify_script->script_.Reset(isolate, v8_script.ToLocalChecked());
@@ -717,6 +731,10 @@ class ContextifyScript : public BaseObject {
           env->cached_data_produced_string(),
           Boolean::New(isolate, cached_data_produced));
     }
+    TRACE_EVENT_NESTABLE_ASYNC_END0(
+        TRACING_CATEGORY_NODE2(vm, script),
+        "ContextifyScript::New",
+        contextify_script);
   }
 
 
@@ -729,6 +747,12 @@ class ContextifyScript : public BaseObject {
   static void RunInThisContext(const FunctionCallbackInfo<Value>& args) {
     Environment* env = Environment::GetCurrent(args);
 
+    ContextifyScript* wrapped_script;
+    ASSIGN_OR_RETURN_UNWRAP(&wrapped_script, args.Holder());
+
+    TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(
+        TRACING_CATEGORY_NODE2(vm, script), "RunInThisContext", wrapped_script);
+
     CHECK_EQ(args.Length(), 3);
 
     CHECK(args[0]->IsNumber());
@@ -742,11 +766,17 @@ class ContextifyScript : public BaseObject {
 
     // Do the eval within this context
     EvalMachine(env, timeout, display_errors, break_on_sigint, args);
+
+    TRACE_EVENT_NESTABLE_ASYNC_END0(
+        TRACING_CATEGORY_NODE2(vm, script), "RunInThisContext", wrapped_script);
   }
 
   static void RunInContext(const FunctionCallbackInfo<Value>& args) {
     Environment* env = Environment::GetCurrent(args);
 
+    ContextifyScript* wrapped_script;
+    ASSIGN_OR_RETURN_UNWRAP(&wrapped_script, args.Holder());
+
     CHECK_EQ(args.Length(), 4);
 
     CHECK(args[0]->IsObject());
@@ -759,6 +789,9 @@ class ContextifyScript : public BaseObject {
     if (contextify_context->context().IsEmpty())
       return;
 
+    TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(
+        TRACING_CATEGORY_NODE2(vm, script), "RunInContext", wrapped_script);
+
     CHECK(args[1]->IsNumber());
     int64_t timeout = args[1]->IntegerValue(env->context()).FromJust();
 
@@ -775,6 +808,9 @@ class ContextifyScript : public BaseObject {
                 display_errors,
                 break_on_sigint,
                 args);
+
+    TRACE_EVENT_NESTABLE_ASYNC_END0(
+        TRACING_CATEGORY_NODE2(vm, script), "RunInContext", wrapped_script);
   }
 
   static void DecorateErrorStack(Environment* env, const TryCatch& try_catch) {

test/parallel/test-trace-events-vm.js

@@ -0,0 +1,42 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cp = require('child_process');
+const path = require('path');
+const fs = require('fs');
+const tmpdir = require('../common/tmpdir');
+
+const names = [
+  'ContextifyScript::New',
+  'RunInThisContext',
+  'RunInContext'
+];
+
+if (process.argv[2] === 'child') {
+  const vm = require('vm');
+  vm.runInNewContext('1 + 1');
+} else {
+  tmpdir.refresh();
+  process.chdir(tmpdir.path);
+
+  const proc = cp.fork(__filename,
+                       [ 'child' ], {
+                         execArgv: [
+                           '--trace-event-categories',
+                           'node.vm.script'
+                         ]
+                       });
+
+  proc.once('exit', common.mustCall(() => {
+    const file = path.join(tmpdir.path, 'node_trace.1.log');
+
+    assert(common.fileExists(file));
+    fs.readFile(file, common.mustCall((err, data) => {
+      const traces = JSON.parse(data.toString()).traceEvents;
+      traces.forEach((trace) => {
+        assert.strictEqual(trace.pid, proc.pid);
+        assert(names.includes(trace.name));
+      });
+    }));
+  }));
+}