Use count-based profiling exclusively.

src/x64/full-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 307 matching lines @@
   }
   __ movq(rbx, profiling_counter_, RelocInfo::EMBEDDED_OBJECT);
   __ movq(kScratchRegister,
           reinterpret_cast<uint64_t>(Smi::FromInt(reset_value)),
           RelocInfo::NONE);
   __ movq(FieldOperand(rbx, JSGlobalPropertyCell::kValueOffset),
           kScratchRegister);
 }
 
 
-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
   // in a test instruction after the call so we can extract it from the OSR
   // builtin.
   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);
   // Record a mapping of the OSR id to this PC.  This is used if the OSR
   // entry becomes the target of a bailout.  We don't expect it to be, but
   // we want it to work if it is.
   PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
 }
 
 
@@ skipping 837 matching lines @@
   }
 
   // Generate code for the body of the loop.
   Visit(stmt->body());
 
   // Generate code for going to the next element by incrementing the
   // index (smi) stored on top of the stack.
   __ 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.
   __ bind(loop_statement.break_label());
   __ addq(rsp, Immediate(5 * kPointerSize));
 
   // Exit and decrement the loop depth.
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
   __ bind(&exit);
   decrement_loop_depth();
@@ skipping 3292 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64