Moves SingleStepHandler runtime calls

runtime/vm/stub_code_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"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 1458 matching lines @@
     ASSERT(ICData::NumArgsTestedShift() == 0);  // No shift needed.
     __ andq(RCX, Immediate(ICData::NumArgsTestedMask()));
     __ cmpq(RCX, Immediate(0));
     __ j(EQUAL, &ok, Assembler::kNearJump);
     __ Stop("Incorrect IC data for unoptimized static call");
     __ Bind(&ok);
   }
 #endif  // DEBUG
 
   // Check single stepping.
-  Label not_stepping;
+  Label stepping, done_stepping;
   __ movq(RAX, FieldAddress(CTX, Context::isolate_offset()));
   __ movzxb(RAX, Address(RAX, Isolate::single_step_offset()));
   __ cmpq(RAX, Immediate(0));
-  __ j(EQUAL, &not_stepping, Assembler::kNearJump);
-  __ EnterStubFrame();
-  __ pushq(RBX);  // Preserve IC data object.
-  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
-  __ popq(RBX);
-  __ LeaveStubFrame();
-  __ Bind(&not_stepping);
+  __ j(NOT_EQUAL, &stepping, Assembler::kNearJump);
+  __ Bind(&done_stepping);
 
   // RBX: IC data object (preserved).
   __ movq(R12, FieldAddress(RBX, ICData::ic_data_offset()));
   // R12: ic_data_array with entries: target functions and count.
   __ leaq(R12, FieldAddress(R12, Array::data_offset()));
   // R12: 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;
-  __ addq(Address(R12, count_offset), Immediate(Smi::RawValue(1)));
-  __ j(NO_OVERFLOW, &increment_done, Assembler::kNearJump);
-  __ movq(Address(R12, count_offset),
-          Immediate(Smi::RawValue(Smi::kMaxValue)));
-  __ Bind(&increment_done);
+  __ movq(R8, Address(R12, count_offset));
+  __ addq(R8, Immediate(Smi::RawValue(1)));
+  __ movq(R9, Immediate(Smi::RawValue(Smi::kMaxValue)));
+  __ cmovnoq(R9, R8);
+  __ movq(Address(R12, count_offset), R9);
 
   // Load arguments descriptor into R10.
   __ movq(R10, FieldAddress(RBX, ICData::arguments_descriptor_offset()));
 
   // Get function and call it, if possible.
   __ movq(RAX, Address(R12, target_offset));
   __ movq(RCX, FieldAddress(RAX, Function::instructions_offset()));
   // RCX: Target instructions.
   __ addq(RCX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(RCX);
+
+  __ Bind(&stepping);
+  __ EnterStubFrame();
+  __ pushq(RBX);  // Preserve IC data object.
+  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
+  __ popq(RBX);
+  __ LeaveStubFrame();
+  __ jmp(&done_stepping, Assembler::kNearJump);
 }
 
 
 void StubCode::GenerateTwoArgsUnoptimizedStaticCallStub(Assembler* assembler) {
   GenerateUsageCounterIncrement(assembler, RCX);
   GenerateNArgsCheckInlineCacheStub(
       assembler, 2, kStaticCallMissHandlerTwoArgsRuntimeEntry);
 }
 
 
@@ skipping 68 matching lines @@
   __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
   __ popq(RAX);  // Address of original.
   __ LeaveStubFrame();
   __ jmp(RAX);   // Jump to original stub.
 }
 
 
 // Called only from unoptimized code.
 void StubCode::GenerateDebugStepCheckStub(Assembler* assembler) {
   // Check single stepping.
-  Label not_stepping;
+  Label stepping, done_stepping;
   __ movq(RAX, FieldAddress(CTX, Context::isolate_offset()));
   __ movzxb(RAX, Address(RAX, Isolate::single_step_offset()));
   __ cmpq(RAX, Immediate(0));
-  __ j(EQUAL, &not_stepping, Assembler::kNearJump);
+  __ j(NOT_EQUAL, &stepping, Assembler::kNearJump);
+  __ Bind(&done_stepping);
+  __ ret();
 
+  __ Bind(&stepping);
   __ EnterStubFrame();
   __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
   __ LeaveStubFrame();
-  __ Bind(&not_stepping);
-
-  __ ret();
+  __ jmp(&done_stepping, Assembler::kNearJump);
 }
 
 
 // Used to check class and type arguments. Arguments passed on stack:
 // TOS + 0: return address.
 // TOS + 1: instantiator type arguments (can be NULL).
 // TOS + 2: instance.
 // TOS + 3: SubtypeTestCache.
 // Result in RCX: null -> not found, otherwise result (true or false).
 static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
@@ skipping 234 matching lines @@
 
 
 // Called only from unoptimized code. All relevant registers have been saved.
 // TOS + 0: return address
 // TOS + 1: right argument.
 // TOS + 2: left argument.
 // Returns ZF set.
 void StubCode::GenerateUnoptimizedIdenticalWithNumberCheckStub(
     Assembler* assembler) {
   // Check single stepping.
-  Label not_stepping;
+  Label stepping, done_stepping;
   __ movq(RAX, FieldAddress(CTX, Context::isolate_offset()));
   __ movzxb(RAX, Address(RAX, Isolate::single_step_offset()));
   __ cmpq(RAX, Immediate(0));
-  __ j(EQUAL, &not_stepping, Assembler::kNearJump);
-  __ EnterStubFrame();
-  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
-  __ LeaveStubFrame();
-  __ Bind(&not_stepping);
+  __ j(NOT_EQUAL, &stepping);
+  __ Bind(&done_stepping);
 
   const Register left = RAX;
   const Register right = RDX;
 
   __ movq(left, Address(RSP, 2 * kWordSize));
   __ movq(right, Address(RSP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
+
+  __ Bind(&stepping);
+  __ EnterStubFrame();
+  __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
+  __ LeaveStubFrame();
+  __ jmp(&done_stepping);
 }
 
 
 // Called from optimized code only.
 // TOS + 0: return address
 // TOS + 1: right argument.
 // TOS + 2: left argument.
 // Returns ZF set.
 void StubCode::GenerateOptimizedIdenticalWithNumberCheckStub(
     Assembler* assembler) {
   const Register left = RAX;
   const Register right = RDX;
 
   __ movq(left, Address(RSP, 2 * kWordSize));
   __ movq(right, Address(RSP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64