[turbofan] Delay initialization in escape analysis

This is also a refactoring of the merge function in
escape analysis.

BUG=v8:4586
LOG=n

Review URL: https://codereview.chromium.org/1654163003

Cr-Commit-Position: refs/heads/master@{#33728}

src/compiler/escape-analysis-reducer.cc

@@ -133,6 +133,9 @@ Reduction EscapeAnalysisReducer::ReduceStore(Node* node) {
 
 Reduction EscapeAnalysisReducer::ReduceAllocate(Node* node) {
   DCHECK_EQ(node->opcode(), IrOpcode::kAllocate);
+  if (node->id() < static_cast<NodeId>(fully_reduced_.length())) {
+    fully_reduced_.Add(node->id());
+  }
   if (escape_analysis()->IsVirtual(node)) {
     RelaxEffectsAndControls(node);
     counters()->turbo_escape_allocs_replaced()->Increment();
@@ -147,6 +150,8 @@ Reduction EscapeAnalysisReducer::ReduceFinishRegion(Node* node) {
   DCHECK_EQ(node->opcode(), IrOpcode::kFinishRegion);
   Node* effect = NodeProperties::GetEffectInput(node, 0);
   if (effect->opcode() == IrOpcode::kBeginRegion) {
+    // We only add it now to remove empty Begin/Finish region pairs
+    // in the process.
     if (node->id() < static_cast<NodeId>(fully_reduced_.length())) {
       fully_reduced_.Add(node->id());
     }
@@ -208,6 +213,9 @@ Reduction EscapeAnalysisReducer::ReduceObjectIsSmi(Node* node) {
 
 Reduction EscapeAnalysisReducer::ReduceFrameStateUses(Node* node) {
   DCHECK_GE(node->op()->EffectInputCount(), 1);
+  if (node->id() < static_cast<NodeId>(fully_reduced_.length())) {
+    fully_reduced_.Add(node->id());
+  }
   bool changed = false;
   for (int i = 0; i < node->InputCount(); ++i) {
     Node* input = node->InputAt(i);

src/compiler/escape-analysis.h

@@ -149,8 +149,6 @@ class EscapeAnalysis {
   VirtualObject* CopyForModificationAt(VirtualObject* obj, VirtualState* state,
                                        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);

src/flag-definitions.h

@@ -467,7 +467,6 @@ DEFINE_BOOL(turbo_frame_elision, true, "elide frames in TurboFan")
 DEFINE_BOOL(turbo_cache_shared_code, true, "cache context-independent code")
 DEFINE_BOOL(turbo_preserve_shared_code, false, "keep context-independent code")
 DEFINE_BOOL(turbo_escape, false, "enable escape analysis")
-DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
 DEFINE_BOOL(turbo_instruction_scheduling, false,
             "enable instruction scheduling in TurboFan")
 
@@ -955,6 +954,7 @@ DEFINE_BOOL(print_global_handles, false, "report global handles after GC")
 // TurboFan debug-only flags.
 DEFINE_BOOL(print_turbo_replay, false,
             "print C++ code to recreate TurboFan graphs")
+DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
 
 // objects.cc
 DEFINE_BOOL(trace_normalization, false,