Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(240)

Unified Diff: runtime/vm/optimizer.cc

Issue 2904543002: Fix misoptimization of 'is' test (Closed)
Patch Set: Feedback from Slava, do same optimization on AOT and JIT Created 3 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « runtime/vm/optimizer.h ('k') | runtime/vm/vm_sources.gypi » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: runtime/vm/optimizer.cc
diff --git a/runtime/vm/optimizer.cc b/runtime/vm/optimizer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..24f5e058009f3ee657bafba7de2b7f4cc76fe346
--- /dev/null
+++ b/runtime/vm/optimizer.cc
@@ -0,0 +1,96 @@
+// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "vm/optimizer.h"
+
+#include "vm/intermediate_language.h"
+#include "vm/object.h"
+
+namespace dart {
+
+static bool CidTestResultsContains(const ZoneGrowableArray<intptr_t>& results,
+ intptr_t test_cid) {
+ for (intptr_t i = 0; i < results.length(); i += 2) {
+ if (results[i] == test_cid) return true;
+ }
+ return false;
+}
+
+
+static void TryAddTest(ZoneGrowableArray<intptr_t>* results,
+ intptr_t test_cid,
+ bool result) {
+ if (!CidTestResultsContains(*results, test_cid)) {
+ results->Add(test_cid);
+ results->Add(result);
+ }
+}
+
+
+// Used when we only need the positive result because we return false by
+// default.
+static void PurgeNegativeTestCidsEntries(ZoneGrowableArray<intptr_t>* results) {
+ // We can't purge the Smi entry at the beginning since it is used in the
+ // Smi check before the Cid is loaded.
+ int dest = 2;
+ for (intptr_t i = 2; i < results->length(); i += 2) {
+ if (results->At(i + 1) != 0) {
+ (*results)[dest++] = results->At(i);
+ (*results)[dest++] = results->At(i + 1);
+ }
+ }
+ results->SetLength(dest);
+}
+
+
+bool Optimizer::SpecializeTestCidsForNumericTypes(
+ ZoneGrowableArray<intptr_t>* results,
+ const AbstractType& type) {
+ ASSERT(results->length() >= 2); // At least on entry.
+ const ClassTable& class_table = *Isolate::Current()->class_table();
+ if ((*results)[0] != kSmiCid) {
+ const Class& cls = Class::Handle(class_table.At(kSmiCid));
+ const Class& type_class = Class::Handle(type.type_class());
+ const bool smi_is_subtype =
+ cls.IsSubtypeOf(Object::null_type_arguments(), type_class,
+ Object::null_type_arguments(), NULL, NULL, Heap::kOld);
+ results->Add((*results)[results->length() - 2]);
+ results->Add((*results)[results->length() - 2]);
+ for (intptr_t i = results->length() - 3; i > 1; --i) {
+ (*results)[i] = (*results)[i - 2];
+ }
+ (*results)[0] = kSmiCid;
+ (*results)[1] = smi_is_subtype;
+ }
+
+ ASSERT(type.IsInstantiated() && !type.IsMalformedOrMalbounded());
+ ASSERT(results->length() >= 2);
+ if (type.IsSmiType()) {
+ ASSERT((*results)[0] == kSmiCid);
+ PurgeNegativeTestCidsEntries(results);
+ return false;
+ } else if (type.IsIntType()) {
+ ASSERT((*results)[0] == kSmiCid);
+ TryAddTest(results, kMintCid, true);
+ TryAddTest(results, kBigintCid, true);
+ // Cannot deoptimize since all tests returning true have been added.
+ PurgeNegativeTestCidsEntries(results);
+ return false;
+ } else if (type.IsNumberType()) {
+ ASSERT((*results)[0] == kSmiCid);
+ TryAddTest(results, kMintCid, true);
+ TryAddTest(results, kBigintCid, true);
+ TryAddTest(results, kDoubleCid, true);
+ PurgeNegativeTestCidsEntries(results);
+ return false;
+ } else if (type.IsDoubleType()) {
+ ASSERT((*results)[0] == kSmiCid);
+ TryAddTest(results, kDoubleCid, true);
+ PurgeNegativeTestCidsEntries(results);
+ return false;
+ }
+ return true; // May deoptimize since we have not identified all 'true' tests.
+}
+
+} // namespace dart
« no previous file with comments | « runtime/vm/optimizer.h ('k') | runtime/vm/vm_sources.gypi » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698