Moves infrequently used debugger code in CheckInlineCachestub.

runtime/vm/stub_code_arm64.cc

 // Copyright (c) 2014, 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"
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 1329 matching lines @@
                       kNoPP, kUnsignedWord);
     ASSERT(ICData::NumArgsTestedShift() == 0);  // No shift needed.
     __ andi(R6, R6, ICData::NumArgsTestedMask());
     __ CompareImmediate(R6, num_args, kNoPP);
     __ b(&ok, EQ);
     __ Stop("Incorrect stub for IC data");
     __ Bind(&ok);
   }
 #endif  // DEBUG
 
+  Label stepping, done_stepping;
   if (FLAG_enable_debugger) {
     // Check single stepping.
-    Label not_stepping;
     __ LoadFieldFromOffset(R6, CTX, Context::isolate_offset(), kNoPP);
     __ LoadFromOffset(
         R6, R6, Isolate::single_step_offset(), kNoPP, kUnsignedByte);
     __ CompareRegisters(R6, ZR);
-    __ b(&not_stepping, EQ);
-    __ EnterStubFrame();
-    __ Push(R5);  // Preserve IC data.
-    __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
-    __ Pop(R5);
-    __ LeaveStubFrame();
-    __ Bind(&not_stepping);
+    __ b(&stepping, NE);
+    __ Bind(&done_stepping);
   }
 
   // Load arguments descriptor into R4.
   __ LoadFieldFromOffset(R4, R5, ICData::arguments_descriptor_offset(), kNoPP);
   // Loop that checks if there is an IC data match.
   Label loop, update, test, found;
   // R5: IC data object (preserved).
   __ LoadFieldFromOffset(R6, R5, ICData::ic_data_offset(), kNoPP);
   // R6: ic_data_array with check entries: classes and target functions.
   __ AddImmediate(R6, R6, Array::data_offset() - kHeapObjectTag, kNoPP);
@@ skipping 95 matching lines @@
   __ LoadImmediate(R2, Smi::RawValue(Smi::kMaxValue), kNoPP);
   __ csel(R1, R2, R1, VS);  // Overflow.
   __ StoreToOffset(R1, R6, count_offset, kNoPP);
 
   __ Bind(&call_target_function);
   // R0: target function.
   __ LoadFieldFromOffset(R2, R0, Function::instructions_offset(), kNoPP);
   __ AddImmediate(
       R2, R2, Instructions::HeaderSize() - kHeapObjectTag, kNoPP);
   __ br(R2);
+
+  if (FLAG_enable_debugger) {
+    __ Bind(&stepping);
+    __ EnterStubFrame();
+    __ Push(R5);  // Preserve IC data.
+    __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
+    __ Pop(R5);
+    __ LeaveStubFrame();
+    __ b(&done_stepping);
+  }
 }
 
 
 // Use inline cache data array to invoke the target or continue in inline
 // cache miss handler. Stub for 1-argument check (receiver class).
 //  LR: return address.
 //  R5: inline cache data object.
 // Inline cache data object structure:
 // 0: function-name
 // 1: N, number of arguments checked.
@@ skipping 443 matching lines @@
   const Register right = R0;
   __ LoadFromOffset(left, SP, 1 * kWordSize, kNoPP);
   __ LoadFromOffset(right, SP, 0 * kWordSize, kNoPP);
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64