[vm] Remove dead copy_parent_code flag.

TEST=ci
Change-Id: Ib167a667f03179f9bc0f38d8b33d08f867ee9423
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352700
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/bin/main_impl.cc

@@ -759,14 +759,6 @@ static Dart_Isolate CreateIsolateGroupAndSetupHelper(
     }
   }
 
-  if (flags->copy_parent_code && callback_data != nullptr) {
-    auto parent_isolate_group_data =
-        reinterpret_cast<IsolateData*>(callback_data)->isolate_group_data();
-    kernel_buffer_ptr = parent_isolate_group_data->kernel_buffer();
-    kernel_buffer = kernel_buffer_ptr.get();
-    kernel_buffer_size = parent_isolate_group_data->kernel_buffer_size();
-  }
-
   if (kernel_buffer == nullptr && !isolate_run_app_snapshot) {
     dfe.ReadScript(script_uri, app_snapshot, &kernel_buffer,
                    &kernel_buffer_size, /*decode_uri=*/true,

runtime/include/dart_api.h

@@ -589,7 +589,6 @@ typedef struct {
   bool use_osr;
   bool obfuscate;
   bool load_vmservice_library;
-  bool copy_parent_code;
   bool null_safety;
   bool is_system_isolate;
   bool is_service_isolate;

runtime/lib/isolate.cc

@@ -913,9 +913,6 @@ DEFINE_NATIVE_ENTRY(Isolate_spawnFunction, 0, 10) {
       paused.value(), fatal_errors, on_exit_port, on_error_port,
       utf8_debug_name, isolate->group()));
 
-  // Since this is a call to Isolate.spawn, copy the parent isolate's code.
-  state->isolate_flags()->copy_parent_code = true;
-
   isolate->group()->thread_pool()->Run<SpawnIsolateTask>(isolate,
                                                          std::move(state));
   return Object::null();
@@ -1010,9 +1007,6 @@ DEFINE_NATIVE_ENTRY(Isolate_spawnUri, 0, 12) {
     flags->enable_asserts = checked.value();
   }
 
-  // Since this is a call to Isolate.spawnUri, don't copy the parent's code.
-  state->isolate_flags()->copy_parent_code = false;
-
   isolate->group()->thread_pool()->Run<SpawnIsolateTask>(isolate,
                                                          std::move(state));
   return Object::null();

runtime/vm/isolate.cc

@@ -1539,7 +1539,6 @@ void IsolateGroup::FlagsInitialize(Dart_IsolateFlags* api_flags) {
   api_flags->isolate_flag = flag;
   BOOL_ISOLATE_GROUP_FLAG_LIST(INIT_FROM_FLAG)
 #undef INIT_FROM_FLAG
-  api_flags->copy_parent_code = false;
   api_flags->is_service_isolate = false;
   api_flags->is_kernel_isolate = false;
 }
@@ -1550,7 +1549,6 @@ void IsolateGroup::FlagsCopyTo(Dart_IsolateFlags* api_flags) {
   api_flags->isolate_flag = name();
   BOOL_ISOLATE_GROUP_FLAG_LIST(INIT_FROM_FIELD)
 #undef INIT_FROM_FIELD
-  api_flags->copy_parent_code = false;
   api_flags->is_service_isolate = false;
   api_flags->is_kernel_isolate = false;
 }
@@ -1592,7 +1590,6 @@ void Isolate::FlagsInitialize(Dart_IsolateFlags* api_flags) {
   api_flags->isolate_flag = flag;
   BOOL_ISOLATE_FLAG_LIST(INIT_FROM_FLAG)
 #undef INIT_FROM_FLAG
-  api_flags->copy_parent_code = false;
   api_flags->is_service_isolate = false;
   api_flags->is_kernel_isolate = false;
 }
@@ -1605,13 +1602,11 @@ void Isolate::FlagsCopyTo(Dart_IsolateFlags* api_flags) const {
   api_flags->isolate_flag = name();
   BOOL_ISOLATE_FLAG_LIST(INIT_FROM_FIELD)
 #undef INIT_FROM_FIELD
-  api_flags->copy_parent_code = false;
   api_flags->is_service_isolate = false;
   api_flags->is_kernel_isolate = false;
 }
 
 void Isolate::FlagsCopyFrom(const Dart_IsolateFlags& api_flags) {
-  const bool copy_parent_code_ = copy_parent_code();
 #if defined(DART_PRECOMPILER)
 #define FLAG_FOR_PRECOMPILER(action) action
 #else
@@ -1631,7 +1626,6 @@ void Isolate::FlagsCopyFrom(const Dart_IsolateFlags& api_flags) {
                       api_flags.isolate_flag, isolate_flags_));
 
   BOOL_ISOLATE_FLAG_LIST(SET_FROM_FLAG)
-  isolate_flags_ = CopyParentCodeBit::update(copy_parent_code_, isolate_flags_);
 #undef FLAG_FOR_NONPRODUCT
 #undef FLAG_FOR_PRECOMPILER
 #undef FLAG_FOR_PRODUCT

runtime/vm/isolate.h

@@ -155,7 +155,6 @@ typedef FixedCache<intptr_t, CatchEntryMovesRefPtr, 16> CatchEntryMovesCache;
     FLAG_branch_coverage)
 
 #define BOOL_ISOLATE_FLAG_LIST_DEFAULT_GETTER(V)                               \
-  V(PRODUCT, copy_parent_code, CopyParentCode, copy_parent_code, false)        \
   V(NONPRODUCT, is_system_isolate, IsSystemIsolate, is_system_isolate, false)  \
   V(NONPRODUCT, is_service_isolate, IsServiceIsolate, is_service_isolate,      \
     false)                                                                     \
@@ -1567,7 +1566,6 @@ class Isolate : public BaseIsolate, public IntrusiveDListEntry<Isolate> {
   V(ResumeRequest)                                                             \
   V(HasAttemptedStepping)                                                      \
   V(ShouldPausePostServiceRequest)                                             \
-  V(CopyParentCode)                                                            \
   V(IsSystemIsolate)                                                           \
   V(IsServiceRegistered)