From 3986012f4c1fa4f8d6ccceb672072cb436d660d3 Mon Sep 17 00:00:00 2001
From: Clemens Backes <clemensb@chromium.org>
Date: Fri, 3 Dec 2021 13:13:39 +0100
Subject: [PATCH] [d8] Make --dump-counters a d8-only flag

--dump-counters and --dump-counters-nvp are only functional in d8, thus
they should be d8-only flags.

R=mlippautz@chromium.org

Bug: v8:12464
Change-Id: Ie3295990a1b4691ab95f8403ff6d9932543b03cd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3312275
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78247}
---
 src/d8/d8.cc                 | 18 +++++++++++-------
 src/d8/d8.h                  |  2 ++
 src/flags/flag-definitions.h |  5 +----
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/d8/d8.cc b/src/d8/d8.cc
index f762ce8291..081a4a54d0 100644
--- a/src/d8/d8.cc
+++ b/src/d8/d8.cc
@@ -3360,22 +3360,18 @@ void Shell::OnExit(v8::Isolate* isolate, bool dispose) {
     i::Isolate::Delete(reinterpret_cast<i::Isolate*>(shared_isolate));
   }
 
-  // {V8::Dispose} resets flags, thus get the flag values before disposing.
-  bool dump_counters = i::FLAG_dump_counters;
-  bool dump_counters_nvp = i::FLAG_dump_counters_nvp;
-
   if (dispose) {
     V8::Dispose();
     V8::DisposePlatform();
   }
 
-  if (dump_counters || dump_counters_nvp) {
+  if (options.dump_counters || options.dump_counters_nvp) {
     base::SharedMutexGuard<base::kShared> mutex_guard(&counter_mutex_);
     std::vector<std::pair<std::string, Counter*>> counters(
         counter_map_->begin(), counter_map_->end());
     std::sort(counters.begin(), counters.end());
 
-    if (dump_counters_nvp) {
+    if (options.dump_counters_nvp) {
       // Dump counters as name-value pairs.
       for (const auto& pair : counters) {
         std::string key = pair.first;
@@ -4358,6 +4354,14 @@ bool Shell::SetOptions(int argc, char* argv[]) {
     } else if (strcmp(argv[i], "--no-fail") == 0) {
       options.no_fail = true;
       argv[i] = nullptr;
+    } else if (strcmp(argv[i], "--dump-counters") == 0) {
+      i::FLAG_slow_histograms = true;
+      options.dump_counters = true;
+      argv[i] = nullptr;
+    } else if (strcmp(argv[i], "--dump-counters-nvp") == 0) {
+      i::FLAG_slow_histograms = true;
+      options.dump_counters_nvp = true;
+      argv[i] = nullptr;
     } else if (strncmp(argv[i], "--icu-data-file=", 16) == 0) {
       options.icu_data_file = argv[i] + 16;
       argv[i] = nullptr;
@@ -5208,7 +5212,7 @@ int Shell::Main(int argc, char* argv[]) {
       base::SysInfo::AmountOfVirtualMemory());
 
   Shell::counter_map_ = new CounterMap();
-  if (i::FLAG_dump_counters || i::FLAG_dump_counters_nvp ||
+  if (options.dump_counters || options.dump_counters_nvp ||
       i::TracingFlags::is_gc_stats_enabled()) {
     create_params.counter_lookup_callback = LookupCounter;
     create_params.create_histogram_callback = CreateHistogram;
diff --git a/src/d8/d8.h b/src/d8/d8.h
index 63f68e32dd..49a514a639 100644
--- a/src/d8/d8.h
+++ b/src/d8/d8.h
@@ -393,6 +393,8 @@ class ShellOptions {
   bool test_shell = false;
   DisallowReassignment<bool> expected_to_throw = {"throws", false};
   DisallowReassignment<bool> no_fail = {"no-fail", false};
+  DisallowReassignment<bool> dump_counters = {"dump-counters", false};
+  DisallowReassignment<bool> dump_counters_nvp = {"dump-counters-nvp", false};
   DisallowReassignment<bool> ignore_unhandled_promises = {
       "ignore-unhandled-promises", false};
   DisallowReassignment<bool> mock_arraybuffer_allocator = {
diff --git a/src/flags/flag-definitions.h b/src/flags/flag-definitions.h
index 3462e69975..9e6b9bfa3e 100644
--- a/src/flags/flag-definitions.h
+++ b/src/flags/flag-definitions.h
@@ -1879,13 +1879,10 @@ DEFINE_BOOL_READONLY(minor_mc, false,
 DEFINE_BOOL(help, false, "Print usage message, including flags, on console")
 DEFINE_BOOL(print_flag_values, false, "Print all flag values of V8")
 
-DEFINE_BOOL(dump_counters, false, "Dump counters on exit")
+// Slow histograms are also enabled via --dump-counters in d8.
 DEFINE_BOOL(slow_histograms, false,
             "Enable slow histograms with more overhead.")
-DEFINE_IMPLICATION(dump_counters, slow_histograms)
 
-DEFINE_BOOL(dump_counters_nvp, false,
-            "Dump counters as name-value pairs on exit")
 DEFINE_BOOL(use_external_strings, false, "Use external strings for source code")
 DEFINE_STRING(map_counters, "", "Map counters to a file")
 DEFINE_BOOL(mock_arraybuffer_allocator, false,