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[flags] Rename FLAG_max_polymorphic_map_count

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This flag's name is slightly incorrect as it is possible to have more
maps than this in the feecback vector.

This flag doesn't account for deprecated maps in the feedback
vector. To make this explicit, we change the flag to indicate that
this only counts valid maps.

Bug: v8:10582
Change-Id: Ib0cc425a03d590bb21184fc6b104d0ebee1d5b03
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2319992
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69075}
This commit is contained in:
Sathya Gunasekaran 2020-07-27 10:07:14 +01:00 committed by Commit Bot
parent ccd0bf3f6b
commit 926094db88
3 changed files with 8 additions and 7 deletions
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4
src/flags/flag-definitions.h
View File

@ -1283,8 +1283,8 @@ DEFINE_BOOL_READONLY(fast_map_update, false,
"enable fast map update by caching the migration target")
DEFINE_BOOL(modify_field_representation_inplace, true,
"enable in-place field representation updates")
DEFINE_INT(max_polymorphic_map_count, 4,
"maximum number of maps to track in POLYMORPHIC state")
DEFINE_INT(max_valid_polymorphic_map_count, 4,
"maximum number of valid maps to track in POLYMORPHIC state")
DEFINE_BOOL(native_code_counters, DEBUG_BOOL,
"generate extra code for manipulating stats counters")

7
src/ic/ic.cc
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@ -600,7 +600,8 @@ bool IC::UpdatePolymorphicIC(Handle<Name> name,
int number_of_valid_maps =
number_of_maps - deprecated_maps - (handler_to_overwrite != -1);
if (number_of_valid_maps >= FLAG_max_polymorphic_map_count) return false;
if (number_of_valid_maps >= FLAG_max_valid_polymorphic_map_count)
return false;
if (number_of_maps == 0 && state() != MONOMORPHIC && state() != POLYMORPHIC) {
return false;
}
@ -1079,7 +1080,7 @@ void KeyedLoadIC::UpdateLoadElement(Handle<HeapObject> receiver,
// If the maximum number of receiver maps has been exceeded, use the generic
// version of the IC.
if (static_cast<int>(target_receiver_maps.size()) >
FLAG_max_polymorphic_map_count) {
FLAG_max_valid_polymorphic_map_count) {
set_slow_stub_reason("max polymorph exceeded");
return;
}
@ -1900,7 +1901,7 @@ void KeyedStoreIC::UpdateStoreElement(Handle<Map> receiver_map,
// If the maximum number of receiver maps has been exceeded, use the
// megamorphic version of the IC.
if (static_cast<int>(target_maps_and_handlers.size()) >
FLAG_max_polymorphic_map_count) {
FLAG_max_valid_polymorphic_map_count) {
return;
}

4
src/objects/feedback-vector.cc
View File

@ -835,8 +835,8 @@ void FeedbackNexus::ConfigureCloneObject(Handle<Map> source_map,
}
break;
case POLYMORPHIC: {
const int kMaxElements =
FLAG_max_polymorphic_map_count * kCloneObjectPolymorphicEntrySize;
const int kMaxElements = FLAG_max_valid_polymorphic_map_count *
kCloneObjectPolymorphicEntrySize;
Handle<WeakFixedArray> array = Handle<WeakFixedArray>::cast(feedback);
int i = 0;
for (; i < array->length(); i += kCloneObjectPolymorphicEntrySize) {