Caches the edge counter increment size in the isolate()

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1222 matching lines @@
 void FlowGraphCompiler::EmitEdgeCounter() {
   // We do not check for overflow when incrementing the edge counter.  The
   // function should normally be optimized long before the counter can
   // overflow; and though we do not reset the counters when we optimize or
   // deoptimize, there is a bound on the number of
   // optimization/deoptimization cycles we will attempt.
   const Array& counter = Array::ZoneHandle(Array::New(1, Heap::kOld));
   counter.SetAt(0, Smi::Handle(Smi::New(0)));
   __ Comment("Edge counter");
   __ LoadObject(RAX, counter, PP);
-#if defined(DEBUG)
   intptr_t increment_start = assembler_->CodeSize();
-#endif  // DEBUG
   __ IncrementSmiField(FieldAddress(RAX, Array::element_offset(0)), 1);
-#if defined(DEBUG)
-  // If the assertion below fails, update EdgeCounterIncrementSizeInBytes.
-  intptr_t expected = EdgeCounterIncrementSizeInBytes();
-  intptr_t actual = assembler_->CodeSize() - increment_start;
-  if (actual != expected) {
-    FATAL2("Edge counter increment length: %" Pd ", expected %" Pd "\n",
-           actual,
-           expected);
+  int32_t size = assembler_->CodeSize() - increment_start;
+  if (isolate()->edge_counter_increment_size() == -1) {
+    isolate()->set_edge_counter_increment_size(size);
+  } else {
+    ASSERT(size == isolate()->edge_counter_increment_size());
   }
-#endif  // DEBUG
 }
 
 
 int32_t FlowGraphCompiler::EdgeCounterIncrementSizeInBytes() {
-  // Used by CodePatcher; so must be constant across all code in an isolate.
-  int32_t size = 5;
-#if defined(DEBUG)
-  size += 36;  // VerifySmi
-#endif  // DEBUG
-  if (VerifiedMemory::enabled()) {
-    size += 72;
-  }
+  const int32_t size = Isolate::Current()->edge_counter_increment_size();
+  ASSERT(size != -1);
   return size;
 }
 
 
 void FlowGraphCompiler::EmitOptimizedInstanceCall(
     ExternalLabel* target_label,
     const ICData& ic_data,
     intptr_t argument_count,
     intptr_t deopt_id,
     intptr_t token_pos,
@@ skipping 507 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize), PP);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64