Use count-based profiling exclusively.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index c87155f49360e51fc6c79fc5111561bdd55fafd3..68773e96e28fe35229bd57ec1291b4b908cdfdb5 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -325,34 +325,27 @@ void FullCodeGenerator::EmitProfilingCounterReset() {
 }
 
 
-void FullCodeGenerator::EmitStackCheck(IterationStatement* stmt,
-                                       Label* back_edge_target) {
-  Comment cmnt(masm_, "[ Stack check");
+void FullCodeGenerator::EmitBackEdgeBookkeeping(IterationStatement* stmt,
+                                                Label* back_edge_target) {
+  Comment cmnt(masm_, "[ Back edge bookkeeping");
   Label ok;
 
-  if (FLAG_count_based_interrupts) {
-    int weight = 1;
-    if (FLAG_weighted_back_edges) {
-      ASSERT(back_edge_target->is_bound());
-      int distance = masm_->SizeOfCodeGeneratedSince(back_edge_target);
-      weight = Min(kMaxBackEdgeWeight,
-                   Max(1, distance / kBackEdgeDistanceUnit));
-    }
-    EmitProfilingCounterDecrement(weight);
-    __ j(positive, &ok, Label::kNear);
-    InterruptStub stub;
-    __ CallStub(&stub);
-  } else {
-    __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
-    __ j(above_equal, &ok, Label::kNear);
-    StackCheckStub stub;
-    __ CallStub(&stub);
+  int weight = 1;
+  if (FLAG_weighted_back_edges) {
+    ASSERT(back_edge_target->is_bound());
+    int distance = masm_->SizeOfCodeGeneratedSince(back_edge_target);
+    weight = Min(kMaxBackEdgeWeight,
+                 Max(1, distance / kBackEdgeDistanceUnit));
   }
+  EmitProfilingCounterDecrement(weight);
+  __ j(positive, &ok, Label::kNear);
+  InterruptStub stub;
+  __ CallStub(&stub);
 
   // Record a mapping of this PC offset to the OSR id.  This is used to find
   // the AST id from the unoptimized code in order to use it as a key into
   // the deoptimization input data found in the optimized code.
-  RecordStackCheck(stmt->OsrEntryId());
+  RecordBackEdge(stmt->OsrEntryId());
 
   // Loop stack checks can be patched to perform on-stack replacement. In
   // order to decide whether or not to perform OSR we embed the loop depth
@@ -361,9 +354,7 @@ void FullCodeGenerator::EmitStackCheck(IterationStatement* stmt,
   ASSERT(loop_depth() > 0);
   __ testl(rax, Immediate(Min(loop_depth(), Code::kMaxLoopNestingMarker)));
 
-  if (FLAG_count_based_interrupts) {
-    EmitProfilingCounterReset();
-  }
+  EmitProfilingCounterReset();
 
   __ bind(&ok);
   PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
@@ -1221,7 +1212,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ bind(loop_statement.continue_label());
   __ SmiAddConstant(Operand(rsp, 0 * kPointerSize), Smi::FromInt(1));
 
-  EmitStackCheck(stmt, &loop);
+  EmitBackEdgeBookkeeping(stmt, &loop);
   __ jmp(&loop);
 
   // Remove the pointers stored on the stack.