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VM-codegen: For polymorphic methods don't expand Cids at call sites

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When dispatching polymorphic calls we try to recognize the case where
adjacent classes have the same method, so that we can group the classes
in the dispatch.  That fails for polymorphic methods, which are pretending to
be the same method, but actually do a class test on the receiver internally. In
this case, we should not expand the classes, because it messes up some other
inlining optimizations.

R=vegorov@google.com
BUG=https://github.com/dart-lang/sdk/issues/29892

Review-Url: https://codereview.chromium.org/2956653002 .
This commit is contained in:
Erik Corry 2017-06-24 13:36:55 +02:00
parent 8aae79df3b
commit b683e47c1a
1 changed files with 11 additions and 2 deletions
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13
runtime/vm/intermediate_language.cc
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@ -2970,10 +2970,13 @@ CallTargets* CallTargets::CreateAndExpand(Zone* zone, const ICData& ic_data) {
intptr_t length = targets.length();
// Spread class-ids to preceding classes where a lookup yields the same
// method.
// method. A polymorphic target is not really the same method since its
// behaviour depends on the receiver class-id, so we don't spread the
// class-ids in that case.
for (int idx = 0; idx < length; idx++) {
int lower_limit_cid = (idx == 0) ? -1 : targets[idx - 1].cid_end;
const Function& target = *targets.TargetAt(idx)->target;
if (MethodRecognizer::PolymorphicTarget(target)) continue;
for (int i = targets[idx].cid_start - 1; i > lower_limit_cid; i--) {
if (FlowGraphCompiler::LookupMethodFor(i, name, args_desc, &fn) &&
fn.raw() == target.raw()) {
@ -2989,6 +2992,7 @@ CallTargets* CallTargets::CreateAndExpand(Zone* zone, const ICData& ic_data) {
int upper_limit_cid =
(idx == length - 1) ? 1000000000 : targets[idx + 1].cid_start;
const Function& target = *targets.TargetAt(idx)->target;
if (MethodRecognizer::PolymorphicTarget(target)) continue;
for (int i = targets[idx].cid_end + 1; i < upper_limit_cid; i++) {
if (FlowGraphCompiler::LookupMethodFor(i, name, args_desc, &fn) &&
fn.raw() == target.raw()) {
@ -3006,9 +3010,14 @@ CallTargets* CallTargets::CreateAndExpand(Zone* zone, const ICData& ic_data) {
void CallTargets::MergeIntoRanges() {
// Merge adjacent class id ranges.
int dest = 0;
// We merge entries that dispatch to the same target, but polymorphic targets
// are not really the same target since they depend on the class-id, so we
// don't merge them.
for (int src = 1; src < length(); src++) {
const Function& target = *TargetAt(dest)->target;
if (TargetAt(dest)->cid_end + 1 >= TargetAt(src)->cid_start &&
TargetAt(dest)->target->raw() == TargetAt(src)->target->raw()) {
target.raw() == TargetAt(src)->target->raw() &&
!MethodRecognizer::PolymorphicTarget(target)) {
TargetAt(dest)->cid_end = TargetAt(src)->cid_end;
TargetAt(dest)->count += TargetAt(src)->count;
} else {