Moves SingleStepHandler runtime calls

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 1538 matching lines @@
     ASSERT(ICData::NumArgsTestedShift() == 0);  // No shift needed.
     __ andi(R6, R6, ICData::NumArgsTestedMask());
     __ CompareImmediate(R6, 0, kNoPP);
     __ b(&ok, EQ);
     __ Stop("Incorrect IC data for unoptimized static call");
     __ Bind(&ok);
   }
 #endif  // DEBUG
 
   // Check single stepping.
-  Label not_stepping;
+  Label stepping, done_stepping;
   __ LoadFieldFromOffset(R6, CTX, Context::isolate_offset(), kNoPP);
   __ LoadFromOffset(
       R6, R6, Isolate::single_step_offset(), kNoPP, kUnsignedByte);
   __ CompareImmediate(R6, 0, kNoPP);
-  __ 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);
 
   // R5: IC data object (preserved).
   __ LoadFieldFromOffset(R6, R5, ICData::ic_data_offset(), kNoPP);
   // R6: ic_data_array with entries: target functions and count.
   __ AddImmediate(R6, R6, Array::data_offset() - kHeapObjectTag, kNoPP);
   // R6: points directly to the first ic data array element.
   const intptr_t target_offset = ICData::TargetIndexFor(0) * kWordSize;
   const intptr_t count_offset = ICData::CountIndexFor(0) * kWordSize;
 
   // Increment count for this call.
-  Label increment_done;
   __ LoadFromOffset(R1, R6, count_offset, kNoPP);
   __ adds(R1, R1, Operand(Smi::RawValue(1)));
+  __ LoadImmediate(R2, Smi::RawValue(Smi::kMaxValue), kNoPP);
+  __ csel(R1, R2, R1, VS);  // Overflow.
   __ StoreToOffset(R1, R6, count_offset, kNoPP);
-  __ b(&increment_done, VC);  // No overflow.
-  __ LoadImmediate(R1, Smi::RawValue(Smi::kMaxValue), kNoPP);
-  __ StoreToOffset(R1, R6, count_offset, kNoPP);
-  __ Bind(&increment_done);
 
   // Load arguments descriptor into R4.
   __ LoadFieldFromOffset(R4, R5, ICData::arguments_descriptor_offset(), kNoPP);
 
   // Get function and call it, if possible.
   __ LoadFromOffset(R0, R6, target_offset, kNoPP);
   __ LoadFieldFromOffset(R2, R0, Function::instructions_offset(), kNoPP);
 
   // R0: function.
   // R2: target instructons.
   __ AddImmediate(
       R2, R2, Instructions::HeaderSize() - kHeapObjectTag, kNoPP);
   __ br(R2);
+
+  __ Bind(&stepping);
+  __ EnterStubFrame();
+  __ Push(R5);  // Preserve IC data.
+  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
+  __ Pop(R5);
+  __ LeaveStubFrame();
+  __ b(&done_stepping);
 }
 
 
 void StubCode::GenerateTwoArgsUnoptimizedStaticCallStub(Assembler* assembler) {
   GenerateUsageCounterIncrement(assembler, R6);
   GenerateNArgsCheckInlineCacheStub(
       assembler, 2, kStaticCallMissHandlerTwoArgsRuntimeEntry);
 }
 
 
@@ skipping 56 matching lines @@
   __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
   __ Pop(R0);
   __ LeaveStubFrame();
   __ br(R0);
 }
 
 // Called only from unoptimized code. All relevant registers have been saved.
 void StubCode::GenerateDebugStepCheckStub(
     Assembler* assembler) {
   // Check single stepping.
-  Label not_stepping;
+  Label stepping, done_stepping;
   __ LoadFieldFromOffset(R1, CTX, Context::isolate_offset(), kNoPP);
   __ LoadFromOffset(
       R1, R1, Isolate::single_step_offset(), kNoPP, kUnsignedByte);
   __ CompareImmediate(R1, 0, kNoPP);
-  __ b(&not_stepping, EQ);
+  __ b(&stepping, NE);
+  __ Bind(&done_stepping);
+
+  __ ret();
+
+  __ Bind(&stepping);
   __ EnterStubFrame();
   __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
   __ LeaveStubFrame();
-  __ Bind(&not_stepping);
-
-  __ ret();
+  __ b(&done_stepping);
 }
 
 
 // Used to check class and type arguments. Arguments passed in registers:
 // LR: return address.
 // R0: instance (must be preserved).
 // R1: instantiator type arguments or NULL.
 // R2: cache array.
 // Result in R1: null -> not found, otherwise result (true or false).
 static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
@@ skipping 217 matching lines @@
 
 
 // Called only from unoptimized code. All relevant registers have been saved.
 // LR: return address.
 // SP + 4: left operand.
 // SP + 0: right operand.
 // Return Zero condition flag set if equal.
 void StubCode::GenerateUnoptimizedIdenticalWithNumberCheckStub(
     Assembler* assembler) {
     // Check single stepping.
-  Label not_stepping;
+  Label stepping, done_stepping;
   __ LoadFieldFromOffset(R1, CTX, Context::isolate_offset(), kNoPP);
   __ LoadFromOffset(
       R1, R1, Isolate::single_step_offset(), kNoPP, kUnsignedByte);
   __ CompareImmediate(R1, 0, kNoPP);
-  __ b(&not_stepping, EQ);
-  __ EnterStubFrame();
-  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
-  __ LeaveStubFrame();
-  __ Bind(&not_stepping);
+  __ b(&stepping, NE);
+  __ Bind(&done_stepping);
 
   const Register left = R1;
   const Register right = R0;
   __ LoadFromOffset(left, SP, 1 * kWordSize, kNoPP);
   __ LoadFromOffset(right, SP, 0 * kWordSize, kNoPP);
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
+
+  __ Bind(&stepping);
+  __ EnterStubFrame();
+  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
+  __ LeaveStubFrame();
+  __ b(&done_stepping);
 }
 
 
 // Called from optimized code only.
 // LR: return address.
 // SP + 4: left operand.
 // SP + 0: right operand.
 // Return Zero condition flag set if equal.
 void StubCode::GenerateOptimizedIdenticalWithNumberCheckStub(
     Assembler* assembler) {
   const Register temp = R2;
   const Register left = R1;
   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