Implement a variation of scalar replacement for non-escaping allocations.

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/compiler.h"
@@ skipping 433 matching lines @@
   __ addiu(SP, SP, Immediate(2 * kWordSize));
   __ mov(FP, V0);
 
   // Frame is fully rewritten at this point and it is safe to perform a GC.
   // Materialize any objects that were deferred by FillFrame because they
   // require allocation.
   __ EnterStubFrame();
   if (preserve_result) {
     __ Push(T1);  // Preserve result, it will be GC-d here.
   }
-  __ CallRuntime(kDeoptimizeMaterializeDoublesRuntimeEntry);
+  __ PushObject(Smi::ZoneHandle());  // Space for the result.
+  __ CallRuntime(kDeoptimizeMaterializeRuntimeEntry);
+  // Result tells stub how many bytes to remove from the expression stack
+  // of the bottom-most frame. They were used as materialization arguments.
+  __ Pop(T1);
+  __ SmiUntag(T1);
   if (preserve_result) {
     __ Pop(V0);  // Restore result.
   }
+  __ LeaveStubFrame();
 
-  __ LeaveStubFrameAndReturn();
+  // Return.
+  __ jr(RA);
+  __ delay_slot()->addu(SP, SP, T1);  // Remove materialization arguments.
 }
 
 
 void StubCode::GenerateDeoptimizeLazyStub(Assembler* assembler) {
   __ Unimplemented("DeoptimizeLazy stub");
 }
 
 
 void StubCode::GenerateDeoptimizeStub(Assembler* assembler) {
   GenerateDeoptimizationSequence(assembler, false);  // Don't preserve V0.
@@ skipping 1654 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