[turbofan] Escape Analysis improvements

Move replacements out of virtual object. Replacements are
global to the graph and are not dependent on the virtual
state (after they are discovered).

R=mstarzinger@chromium.org
BUG=v8:4586
LOG=n

Review URL: https://codereview.chromium.org/1527533002

Cr-Commit-Position: refs/heads/master@{#32838}

src/compiler/escape-analysis-reducer.cc

@@ -49,7 +49,7 @@ Reduction EscapeAnalysisReducer::Reduce(Node* node) {
 Reduction EscapeAnalysisReducer::ReduceLoad(Node* node) {
   DCHECK(node->opcode() == IrOpcode::kLoadField ||
          node->opcode() == IrOpcode::kLoadElement);
-  if (Node* rep = escape_analysis()->GetReplacement(node, node->id())) {
+  if (Node* rep = escape_analysis()->GetReplacement(node)) {
     if (FLAG_trace_turbo_escape) {
       PrintF("Replaced #%d (%s) with #%d (%s)\n", node->id(),
              node->op()->mnemonic(), rep->id(), rep->op()->mnemonic());
@@ -116,10 +116,10 @@ Reduction EscapeAnalysisReducer::ReduceReferenceEqual(Node* node) {
   Node* right = NodeProperties::GetValueInput(node, 1);
   if (escape_analysis()->IsVirtual(left)) {
     if (escape_analysis()->IsVirtual(right)) {
-      if (Node* rep = escape_analysis()->GetReplacement(node, left->id())) {
+      if (Node* rep = escape_analysis()->GetReplacement(left)) {
         left = rep;
       }
-      if (Node* rep = escape_analysis()->GetReplacement(node, right->id())) {
+      if (Node* rep = escape_analysis()->GetReplacement(right)) {
         right = rep;
       }
       // TODO(sigurds): What to do if either is a PHI?

src/compiler/escape-analysis.h

@@ -107,7 +107,7 @@ class EscapeAnalysis {
 
   void Run();
 
-  Node* GetReplacement(Node* at, NodeId id);
+  Node* GetReplacement(Node* node);
   bool IsVirtual(Node* node);
   bool IsEscaped(Node* node);
 
@@ -134,8 +134,16 @@ class EscapeAnalysis {
   int OffsetFromAccess(Node* node);
 
   VirtualObject* GetVirtualObject(Node* at, NodeId id);
+  VirtualObject* ResolveVirtualObject(VirtualState* state, Node* node);
+  Node* GetReplacementIfSame(ZoneVector<VirtualObject*>& objs);
 
   bool SetEscaped(Node* node);
+  Node* replacement(NodeId id);
+  Node* replacement(Node* node);
+  Node* ResolveReplacement(Node* node);
+  Node* GetReplacement(NodeId id);
+  bool SetReplacement(Node* node, Node* rep);
+  bool UpdateReplacement(VirtualState* state, Node* node, Node* rep);
 
   void DebugPrint();
   void DebugPrintState(VirtualState* state);
@@ -149,6 +157,7 @@ class EscapeAnalysis {
   CommonOperatorBuilder* const common_;
   Zone* const zone_;
   ZoneVector<VirtualState*> virtual_states_;
+  ZoneVector<Node*> replacements_;
   EscapeStatusAnalysis escape_status_;
   MergeCache cache_;
 

test/unittests/compiler/escape-analysis-unittest.cc

@@ -140,11 +140,11 @@ class EscapeAnalysisTest : public GraphTest {
   // ---------------------------------Assertion Helper--------------------------
 
   void ExpectReplacement(Node* node, Node* rep) {
-    EXPECT_EQ(rep, escape_analysis()->GetReplacement(node, node->id()));
+    EXPECT_EQ(rep, escape_analysis()->GetReplacement(node));
   }
 
   void ExpectReplacementPhi(Node* node, Node* left, Node* right) {
-    Node* rep = escape_analysis()->GetReplacement(node, node->id());
+    Node* rep = escape_analysis()->GetReplacement(node);
     ASSERT_NE(nullptr, rep);
     ASSERT_EQ(IrOpcode::kPhi, rep->opcode());
     EXPECT_EQ(left, NodeProperties::GetValueInput(rep, 0));
@@ -270,7 +270,7 @@ TEST_F(EscapeAnalysisTest, BranchNonEscape) {
 
   ExpectVirtual(allocation);
   ExpectReplacementPhi(load, object1, object2);
-  Node* replacement_phi = escape_analysis()->GetReplacement(load, load->id());
+  Node* replacement_phi = escape_analysis()->GetReplacement(load);
 
   Transformation();