[test][d8] Add d8.log.getAndStop helper

The new helper function allows us to write tests for log parsing
without the need of first generating a log file.
This makes it easier guard against errors when the log format changes.

- add d8.log.getAndStop helper
- add basic log test
- fix test that regresses due to changed gc timing

Bug: v8:10668
Change-Id: Ie57171fa98fe90428b89c26289d55fcbf2a70615
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2403245Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69987}

src/d8/d8.cc

@@ -43,6 +43,7 @@
 #include "src/init/v8.h"
 #include "src/interpreter/interpreter.h"
 #include "src/logging/counters.h"
+#include "src/logging/log-utils.h"
 #include "src/objects/managed.h"
 #include "src/objects/objects-inl.h"
 #include "src/objects/objects.h"
@@ -1503,6 +1504,41 @@ void Shell::RealmSharedSet(Local<String> property, Local<Value> value,
   data->realm_shared_.Reset(isolate, value);
 }
 
+void Shell::LogGetAndStop(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  HandleScope handle_scope(isolate);
+
+  std::string file_name = i_isolate->logger()->file_name();
+  if (i::Log::IsLoggingToConsole(file_name)) {
+    Throw(isolate, "Logging to console instead of file.");
+    return;
+  }
+  if (!i_isolate->logger()->is_logging()) {
+    Throw(isolate, "Logging not enabled.");
+    return;
+  }
+
+  std::string raw_log;
+  FILE* log_file = i_isolate->logger()->TearDownAndGetLogFile();
+  CHECK_NOT_NULL(log_file);
+
+  bool exists = false;
+  raw_log = i::ReadFile(log_file, &exists, true);
+  fclose(log_file);
+
+  if (!exists) {
+    Throw(isolate, "Unable to read log file.");
+    return;
+  }
+  Local<String> result =
+      String::NewFromUtf8(isolate, raw_log.c_str(), NewStringType::kNormal,
+                          static_cast<int>(raw_log.size()))
+          .ToLocalChecked();
+
+  args.GetReturnValue().Set(result);
+}
+
 // async_hooks.createHook() registers functions to be called for different
 // lifetime events of each async operation.
 void Shell::AsyncHooksCreateHook(
@@ -2218,6 +2254,13 @@ Local<ObjectTemplate> Shell::CreateRealmTemplate(Isolate* isolate) {
 
 Local<ObjectTemplate> Shell::CreateD8Template(Isolate* isolate) {
   Local<ObjectTemplate> d8_template = ObjectTemplate::New(isolate);
+  {
+    Local<ObjectTemplate> log_template = ObjectTemplate::New(isolate);
+    log_template->Set(isolate, "getAndStop",
+                      FunctionTemplate::New(isolate, LogGetAndStop));
+
+    d8_template->Set(isolate, "log", log_template);
+  }
   return d8_template;
 }
 

src/d8/d8.h

@@ -401,6 +401,8 @@ class Shell : public i::AllStatic {
   static void RealmSharedSet(Local<String> property, Local<Value> value,
                              const PropertyCallbackInfo<void>& info);
 
+  static void LogGetAndStop(const v8::FunctionCallbackInfo<v8::Value>& args);
+
   static void AsyncHooksCreateHook(
       const v8::FunctionCallbackInfo<v8::Value>& args);
   static void AsyncHooksExecutionAsyncId(

test/mjsunit/regress/regress-v8-9656.js

@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax
+// Flags: --allow-natives-syntax --no-flush-bytecode
+// Flags: --no-stress-flush-bytecode
 // Files: test/mjsunit/code-coverage-utils.js
 
 %DebugToggleBlockCoverage(true);

test/mjsunit/tools/log.js

+// Copyright 2020 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.
+
+// Flags: --log-all --log --no-stress-opt
+
+function testFunctionWithFunnyName(o) {
+  return o.a;
+}
+
+(function testLoopWithFunnyName() {
+  const o = {a:1};
+  let result = 0;
+  for (let i = 0; i < 1000; i++) {
+    result += testFunctionWithFunnyName(o);
+  }
+})();
+
+const log = d8.log.getAndStop();
+
+// Check that we have a minimally working log file.
+assertTrue(log.length > 0);
+assertTrue(log.indexOf('v8-version') == 0);
+assertTrue(log.indexOf('testFunctionWithFunnyName') >= 10);
+assertTrue(log.indexOf('testLoopWithFunnyName') >= 10);