Fixes bug in megamorphic instance call on arm64.

runtime/vm/flow_graph_compiler_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"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1260 matching lines @@
   __ mov(R3, R0);
 
   Label loop, update, call_target_function;
   __ b(&loop);
 
   __ Bind(&update);
   __ add(R3, R3, Operand(Smi::RawValue(1)));
   __ Bind(&loop);
   __ and_(R3, R3, Operand(R1));
   const intptr_t base = Array::data_offset();
-  // R3 is smi tagged, but table entries are 8 bytes, so LSL 2.
-  __ add(TMP, R2, Operand(R3, LSL, 2));

[Florian Schneider, 2014/05/20 13:12:49]

Use kWordSizeLog2 instead.

+  // R3 is smi tagged, but table entries are 16 bytes, so LSL 3.

[Florian Schneider, 2014/05/20 13:12:49]

...entries are 2 words, so use LSL kWordSizeLog2.

+  __ add(TMP, R2, Operand(R3, LSL, 3));

[Florian Schneider, 2014/05/20 13:12:49]

Use kWordSizeLog2 instead.

   __ LoadFieldFromOffset(R4, TMP, base, PP);
 
   ASSERT(kIllegalCid == 0);
   __ tst(R4, Operand(R4));
   __ b(&call_target_function, EQ);
   __ CompareRegisters(R4, R0);
   __ b(&update, NE);
 
   __ Bind(&call_target_function);
   // Call the target found in the cache.  For a class id match, this is a
   // proper target for the given name and arguments descriptor.  If the
   // illegal class id was found, the target is a cache miss handler that can
   // be invoked as a normal Dart function.
-  __ add(TMP, R2, Operand(R3, LSL, 2));

[Florian Schneider, 2014/05/20 13:12:49]

Use kWordSizeLog2 instead.

+  __ add(TMP, R2, Operand(R3, LSL, 3));

[Florian Schneider, 2014/05/20 13:12:49]

Use kWordSizeLog2 instead.

   __ LoadFieldFromOffset(R0, TMP, base + kWordSize, PP);
   __ LoadFieldFromOffset(R1, R0, Function::code_offset(), PP);
   __ LoadFieldFromOffset(R1, R1, Code::instructions_offset(), PP);
   __ LoadObject(R5, ic_data, PP);
   __ LoadObject(R4, arguments_descriptor, PP);
   __ AddImmediate(R1, R1, Instructions::HeaderSize() - kHeapObjectTag, PP);
   __ blr(R1);
   AddCurrentDescriptor(PcDescriptors::kOther, Isolate::kNoDeoptId, token_pos);
   RecordSafepoint(locs);
   AddDeoptIndexAtCall(Isolate::ToDeoptAfter(deopt_id), token_pos);
@@ skipping 470 matching lines @@
 void ParallelMoveResolver::RestoreFpuScratch(FpuRegister reg) {
   UNIMPLEMENTED();
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64