Upgrade V8 to version 4.9.385.28
https://chromium.googlesource.com/v8/v8/+/4.9.385.28
FPIIM-449
Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/crankshaft/hydrogen-infer-representation.cc b/src/crankshaft/hydrogen-infer-representation.cc
new file mode 100644
index 0000000..74f264e
--- /dev/null
+++ b/src/crankshaft/hydrogen-infer-representation.cc
@@ -0,0 +1,162 @@
+// Copyright 2013 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/crankshaft/hydrogen-infer-representation.h"
+
+namespace v8 {
+namespace internal {
+
+void HInferRepresentationPhase::AddToWorklist(HValue* current) {
+ if (current->representation().IsTagged()) return;
+ if (!current->CheckFlag(HValue::kFlexibleRepresentation)) return;
+ if (in_worklist_.Contains(current->id())) return;
+ worklist_.Add(current, zone());
+ in_worklist_.Add(current->id());
+}
+
+
+void HInferRepresentationPhase::Run() {
+ // (1) Initialize bit vectors and count real uses. Each phi gets a
+ // bit-vector of length <number of phis>.
+ const ZoneList<HPhi*>* phi_list = graph()->phi_list();
+ int phi_count = phi_list->length();
+ ZoneList<BitVector*> connected_phis(phi_count, zone());
+ for (int i = 0; i < phi_count; ++i) {
+ phi_list->at(i)->InitRealUses(i);
+ BitVector* connected_set = new(zone()) BitVector(phi_count, zone());
+ connected_set->Add(i);
+ connected_phis.Add(connected_set, zone());
+ }
+
+ // (2) Do a fixed point iteration to find the set of connected phis. A
+ // phi is connected to another phi if its value is used either directly or
+ // indirectly through a transitive closure of the def-use relation.
+ bool change = true;
+ while (change) {
+ change = false;
+ // We normally have far more "forward edges" than "backward edges",
+ // so we terminate faster when we walk backwards.
+ for (int i = phi_count - 1; i >= 0; --i) {
+ HPhi* phi = phi_list->at(i);
+ for (HUseIterator it(phi->uses()); !it.Done(); it.Advance()) {
+ HValue* use = it.value();
+ if (use->IsPhi()) {
+ int id = HPhi::cast(use)->phi_id();
+ if (connected_phis[i]->UnionIsChanged(*connected_phis[id]))
+ change = true;
+ }
+ }
+ }
+ }
+
+ // Set truncation flags for groups of connected phis. This is a conservative
+ // approximation; the flag will be properly re-computed after representations
+ // have been determined.
+ if (phi_count > 0) {
+ BitVector done(phi_count, zone());
+ for (int i = 0; i < phi_count; ++i) {
+ if (done.Contains(i)) continue;
+
+ // Check if all uses of all connected phis in this group are truncating.
+ bool all_uses_everywhere_truncating_int32 = true;
+ bool all_uses_everywhere_truncating_smi = true;
+ for (BitVector::Iterator it(connected_phis[i]);
+ !it.Done();
+ it.Advance()) {
+ int index = it.Current();
+ all_uses_everywhere_truncating_int32 &=
+ phi_list->at(index)->CheckFlag(HInstruction::kTruncatingToInt32);
+ all_uses_everywhere_truncating_smi &=
+ phi_list->at(index)->CheckFlag(HInstruction::kTruncatingToSmi);
+ done.Add(index);
+ }
+
+ if (!all_uses_everywhere_truncating_int32) {
+ // Clear truncation flag of this group of connected phis.
+ for (BitVector::Iterator it(connected_phis[i]);
+ !it.Done();
+ it.Advance()) {
+ int index = it.Current();
+ phi_list->at(index)->ClearFlag(HInstruction::kTruncatingToInt32);
+ }
+ }
+ if (!all_uses_everywhere_truncating_smi) {
+ // Clear truncation flag of this group of connected phis.
+ for (BitVector::Iterator it(connected_phis[i]);
+ !it.Done();
+ it.Advance()) {
+ int index = it.Current();
+ phi_list->at(index)->ClearFlag(HInstruction::kTruncatingToSmi);
+ }
+ }
+ }
+ }
+
+ // Simplify constant phi inputs where possible.
+ // This step uses kTruncatingToInt32 flags of phis.
+ for (int i = 0; i < phi_count; ++i) {
+ phi_list->at(i)->SimplifyConstantInputs();
+ }
+
+ // Use the phi reachability information from step 2 to
+ // sum up the non-phi use counts of all connected phis.
+ for (int i = 0; i < phi_count; ++i) {
+ HPhi* phi = phi_list->at(i);
+ for (BitVector::Iterator it(connected_phis[i]);
+ !it.Done();
+ it.Advance()) {
+ int index = it.Current();
+ HPhi* it_use = phi_list->at(index);
+ if (index != i) phi->AddNonPhiUsesFrom(it_use); // Don't count twice.
+ }
+ }
+
+ // Initialize work list
+ for (int i = 0; i < graph()->blocks()->length(); ++i) {
+ HBasicBlock* block = graph()->blocks()->at(i);
+ const ZoneList<HPhi*>* phis = block->phis();
+ for (int j = 0; j < phis->length(); ++j) {
+ AddToWorklist(phis->at(j));
+ }
+
+ for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
+ HInstruction* current = it.Current();
+ AddToWorklist(current);
+ }
+ }
+
+ // Do a fixed point iteration, trying to improve representations
+ while (!worklist_.is_empty()) {
+ HValue* current = worklist_.RemoveLast();
+ current->InferRepresentation(this);
+ in_worklist_.Remove(current->id());
+ }
+
+ // Lastly: any instruction that we don't have representation information
+ // for defaults to Tagged.
+ for (int i = 0; i < graph()->blocks()->length(); ++i) {
+ HBasicBlock* block = graph()->blocks()->at(i);
+ const ZoneList<HPhi*>* phis = block->phis();
+ for (int j = 0; j < phis->length(); ++j) {
+ HPhi* phi = phis->at(j);
+ if (phi->representation().IsNone()) {
+ phi->ChangeRepresentation(Representation::Tagged());
+ }
+ }
+ for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
+ HInstruction* current = it.Current();
+ if (current->representation().IsNone() &&
+ current->CheckFlag(HInstruction::kFlexibleRepresentation)) {
+ if (current->CheckFlag(HInstruction::kCannotBeTagged)) {
+ current->ChangeRepresentation(Representation::Double());
+ } else {
+ current->ChangeRepresentation(Representation::Tagged());
+ }
+ }
+ }
+ }
+}
+
+} // namespace internal
+} // namespace v8