Cache current thread in a reserved register and use it in LoadIsolate

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 683 matching lines @@
   __ JmpPatchable(&stub_code->FixAllocateArrayStubTargetLabel(), new_pp);
 }
 
 
 // Called when invoking Dart code from C++ (VM code).
 // Input parameters:
 //   RSP : points to return address.
 //   RDI : entrypoint of the Dart function to call.
 //   RSI : arguments descriptor array.
 //   RDX : arguments array.
-//   RCX : new context containing the current isolate pointer.
+//   RCX : current thread.
 void StubCode::GenerateInvokeDartCodeStub(Assembler* assembler) {
   // Save frame pointer coming in.
   __ EnterFrame(0);
 
   const Register kEntryPointReg = CallingConventions::kArg1Reg;
   const Register kArgDescReg    = CallingConventions::kArg2Reg;
   const Register kArgsReg       = CallingConventions::kArg3Reg;
+  const Register kThreadReg     = CallingConventions::kArg4Reg;
 
   // At this point, the stack looks like:
   // | saved RBP                                      | <-- RBP
   // | saved PC (return to DartEntry::InvokeFunction) |
 
   const intptr_t kInitialOffset = 1;
   // Save arguments descriptor array.
   const intptr_t kArgumentsDescOffset = -(kInitialOffset) * kWordSize;
   __ pushq(kArgDescReg);
 
   // Save C++ ABI callee-saved registers.
   __ PushRegisters(CallingConventions::kCalleeSaveCpuRegisters,
                    CallingConventions::kCalleeSaveXmmRegisters);
 
   // We now load the pool pointer(PP) as we are about to invoke dart code and we
   // could potentially invoke some intrinsic functions which need the PP to be
   // set up.
   __ LoadPoolPointer(PP);
 
   // If any additional (or fewer) values are pushed, the offsets in
   // kExitLinkSlotFromEntryFp will need to be changed.
 
+  // Set up THR, which caches the current thread in Dart code.
+  if (THR != kThreadReg) {
+    __ movq(THR, kThreadReg);
+  }
   // Load Isolate pointer into kIsolateReg.
   const Register kIsolateReg = RBX;
   __ LoadIsolate(kIsolateReg);
 
   // Save the current VMTag on the stack.
   __ movq(RAX, Address(kIsolateReg, Isolate::vm_tag_offset()));
   __ pushq(RAX);
 
   // Mark that the isolate is executing Dart code.
   __ movq(Address(kIsolateReg, Isolate::vm_tag_offset()),
@@ skipping 554 matching lines @@
   __ Bind(&error);
   __ Stop("Incorrect IC data");
   __ Bind(&ok);
 #endif
 
   if (FLAG_optimization_counter_threshold >= 0) {
     const intptr_t count_offset = ICData::CountIndexFor(num_args) * kWordSize;
     // Update counter.
     __ movq(R8, Address(R12, count_offset));
     __ addq(R8, Immediate(Smi::RawValue(1)));
-    __ movq(R9, Immediate(Smi::RawValue(Smi::kMaxValue)));
-    __ cmovnoq(R9, R8);
-    __ StoreIntoSmiField(Address(R12, count_offset), R9);
+    __ movq(R13, Immediate(Smi::RawValue(Smi::kMaxValue)));
+    __ cmovnoq(R13, R8);
+    __ StoreIntoSmiField(Address(R12, count_offset), R13);
   }
 
   __ ret();
 }
 
 
 // Generate inline cache check for 'num_args'.
 //  RBX: Inline cache data object.
 //  TOS(0): return address
 // Control flow:
@@ skipping 143 matching lines @@
   // R12: Pointer to an IC data check group.
   const intptr_t target_offset = ICData::TargetIndexFor(num_args) * kWordSize;
   const intptr_t count_offset = ICData::CountIndexFor(num_args) * kWordSize;
   __ movq(RAX, Address(R12, target_offset));
 
   if (FLAG_optimization_counter_threshold >= 0) {
     // Update counter.
     __ Comment("Update caller's counter");
     __ movq(R8, Address(R12, count_offset));
     __ addq(R8, Immediate(Smi::RawValue(1)));
-    __ movq(R9, Immediate(Smi::RawValue(Smi::kMaxValue)));
-    __ cmovnoq(R9, R8);
-    __ StoreIntoSmiField(Address(R12, count_offset), R9);
+    __ movq(R13, Immediate(Smi::RawValue(Smi::kMaxValue)));
+    __ cmovnoq(R13, R8);
+    __ StoreIntoSmiField(Address(R12, count_offset), R13);
   }
 
   __ Comment("Call target");
   __ Bind(&call_target_function);
   // RAX: Target function.
   Label is_compiled;
   __ movq(RCX, FieldAddress(RAX, Function::instructions_offset()));
   __ addq(RCX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   if (range_collection_mode == kCollectRanges) {
     __ movq(R8, Address(RSP, + 1 * kWordSize));
     if (num_args == 2) {
-      __ movq(R9, Address(RSP, + 2 * kWordSize));
+      __ movq(R13, Address(RSP, + 2 * kWordSize));
     }
     __ EnterStubFrame();
     __ pushq(RBX);
     if (num_args == 2) {
-      __ pushq(R9);
+      __ pushq(R13);
     }
     __ pushq(R8);
     __ call(RCX);
 
     Label done;
     __ movq(RDX, RAX);
     __ movq(RBX, Address(RBP, kFirstLocalSlotFromFp * kWordSize));
     __ UpdateRangeFeedback(RDX, 2, RBX, RCX, &done);
     __ Bind(&done);
     __ LeaveStubFrame();
@@ skipping 178 matching lines @@
   // 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;
 
   if (FLAG_optimization_counter_threshold >= 0) {
     // Increment count for this call.
     __ movq(R8, Address(R12, count_offset));
     __ addq(R8, Immediate(Smi::RawValue(1)));
-    __ movq(R9, Immediate(Smi::RawValue(Smi::kMaxValue)));
-    __ cmovnoq(R9, R8);
-    __ StoreIntoSmiField(Address(R12, count_offset), R9);
+    __ movq(R13, Immediate(Smi::RawValue(Smi::kMaxValue)));
+    __ cmovnoq(R13, R8);
+    __ StoreIntoSmiField(Address(R12, count_offset), R13);
   }
 
   // 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));
@@ skipping 261 matching lines @@
 
 #if defined(_WIN64)
   Register stacktrace_reg = RBX;
   __ movq(stacktrace_reg, Address(RSP, 5 * kWordSize));
   Register isolate_reg = RDI;
   __ movq(isolate_reg, Address(RSP, 6 * kWordSize));
 #else
   Register stacktrace_reg = CallingConventions::kArg5Reg;
   Register isolate_reg = CallingConventions::kArg6Reg;
 #endif
-
+  // TODO(koda): Pass thread instead of isolate.
+  __ movq(THR, Address(isolate_reg, Isolate::mutator_thread_offset()));
   __ movq(RBP, CallingConventions::kArg3Reg);
   __ movq(RSP, CallingConventions::kArg2Reg);
   __ movq(kStackTraceObjectReg, stacktrace_reg);
   __ movq(kExceptionObjectReg, CallingConventions::kArg4Reg);
   // Set the tag.
   __ movq(Address(isolate_reg, Isolate::vm_tag_offset()),
           Immediate(VMTag::kDartTagId));
   // Clear top exit frame.
   __ movq(Address(isolate_reg, Isolate::top_exit_frame_info_offset()),
           Immediate(0));
@@ skipping 187 matching lines @@
 // Result:
 //  RCX: entry point.
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler, RDI, RBX, RCX);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64