Implements write barrier on MIPS.

runtime/vm/stub_code_mips.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_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/dart_entry.h"
@@ skipping 360 matching lines @@
   __ LeaveStubFrame();
   __ Ret();
 }
 
 
 void StubCode::GenerateAllocateContextStub(Assembler* assembler) {
   __ Unimplemented("AllocateContext stub");
 }
 
 
+DECLARE_LEAF_RUNTIME_ENTRY(void, StoreBufferBlockProcess, Isolate* isolate);
+
+
+// Helper stub to implement Assembler::StoreIntoObject.
+// Input parameters:
+//   T0: Address (i.e. object) being stored into.
 void StubCode::GenerateUpdateStoreBufferStub(Assembler* assembler) {
-  __ Unimplemented("UpdateStoreBuffer stub");
+  // Save values being destroyed.
+  __ addiu(SP, SP, Immediate(-3 * kWordSize));
+  __ sw(T3, Address(SP, 2 * kWordSize));
+  __ sw(T2, Address(SP, 1 * kWordSize));
+  __ sw(T1, Address(SP, 0 * kWordSize));
+
+  // Load the isolate out of the context.
+  // Spilled: T1, T2, T3.
+  // T0: Address being stored.
+  __ lw(T1, FieldAddress(CTX, Context::isolate_offset()));
+
+  // Load top_ out of the StoreBufferBlock and add the address to the pointers_.
+  // T1: Isolate.
+  intptr_t store_buffer_offset = Isolate::store_buffer_block_offset();
+  __ lw(T2, Address(T1, store_buffer_offset + StoreBufferBlock::top_offset()));
+  __ sll(T3, T2, 1);
+  __ addu(T3, T1, T3);
+  __ sw(T0,
+        Address(T3, store_buffer_offset + StoreBufferBlock::pointers_offset()));
+
+  // Increment top_ and check for overflow.
+  // T2: top_
+  // T1: Isolate
+  Label L;
+  __ AddImmediate(T2, 1);
+  __ sw(T2, Address(T1, store_buffer_offset + StoreBufferBlock::top_offset()));
+  __ addiu(CMPRES, T2, Immediate(-StoreBufferBlock::kSize));
+  // Restore values.
+  __ lw(T1, Address(SP, 0 * kWordSize));
+  __ lw(T2, Address(SP, 1 * kWordSize));
+  __ lw(T3, Address(SP, 2 * kWordSize));
+  __ beq(CMPRES, ZR, &L);
+  __ delay_slot()->addiu(SP, SP, Immediate(3 * kWordSize));
+  __ Ret();
+
+  // Handle overflow: Call the runtime leaf function.
+  __ Bind(&L);
+  // Setup frame, push callee-saved registers.
+
+  __ EnterCallRuntimeFrame(0 * kWordSize);
+  __ lw(T0, FieldAddress(CTX, Context::isolate_offset()));
+  __ CallRuntime(kStoreBufferBlockProcessRuntimeEntry);
+  // Restore callee-saved registers, tear down frame.
+  __ LeaveCallRuntimeFrame();
+  __ Ret();
 }
 
 
 // Called for inline allocation of objects.
 // Input parameters:
 //   RA : return address.
 //   SP + 4 : type arguments object (only if class is parameterized).
 //   SP + 0 : type arguments of instantiator (only if class is parameterized).
 void StubCode::GenerateAllocationStubForClass(Assembler* assembler,
                                               const Class& cls) {
@@ skipping 708 matching lines @@
   __ Bind(&done);
   __ lw(T0, Address(SP, 0 * kWordSize));
   __ lw(T1, Address(SP, 1 * kWordSize));
   __ Ret();
   __ delay_slot()->addiu(SP, SP, Immediate(2 * kWordSize));
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS