DBC: Support large offsets in optimized field access.

runtime/vm/simulator_dbc.cc

 // Copyright (c) 2016, 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 <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_DBC)
 
@@ skipping 2358 matching lines @@
     RawInstance* instance = reinterpret_cast<RawInstance*>(FP[rA]);
     RawObject* value = reinterpret_cast<RawObject*>(FP[value_reg]);
 
     instance->StorePointer(
         reinterpret_cast<RawObject**>(instance->ptr()) + offset_in_words,
         value);
     DISPATCH();
   }
 
   {
+    BYTECODE(StoreFieldExt, A_D);
+    // The offset is stored in the following nop-instruction which is skipped.
+    const uint16_t offset_in_words = Bytecode::DecodeD(*pc++);
+    RawInstance* instance = reinterpret_cast<RawInstance*>(FP[rA]);
+    RawObject* value = reinterpret_cast<RawObject*>(FP[rD]);

[zra, 2016/10/07 20:43:16]

FP is already a RawObject**

[Florian Schneider, 2016/10/07 20:57:18]

Done here and for StoreField.

+
+    instance->StorePointer(
+        reinterpret_cast<RawObject**>(instance->ptr()) + offset_in_words,
+        value);
+    DISPATCH();
+  }
+
+  {
     BYTECODE(StoreFieldTOS, A_D);
     const uint16_t offset_in_words = rD;
     RawInstance* instance = reinterpret_cast<RawInstance*>(SP[-1]);
     RawObject* value = reinterpret_cast<RawObject*>(SP[0]);
     SP -= 2;  // Drop instance and value.
     instance->StorePointer(
         reinterpret_cast<RawObject**>(instance->ptr()) + offset_in_words,
         value);
 
     DISPATCH();
   }
 
   {
     BYTECODE(LoadField, A_B_C);
     const uint16_t instance_reg = rB;
     const uint16_t offset_in_words = rC;
     RawInstance* instance = reinterpret_cast<RawInstance*>(FP[instance_reg]);
     FP[rA] = reinterpret_cast<RawObject**>(instance->ptr())[offset_in_words];
     DISPATCH();
   }
 
   {
+    BYTECODE(LoadFieldExt, A_D);
+    // The offset is stored in the following nop-instruction which is skipped.
+    const uint16_t offset_in_words = Bytecode::DecodeD(*pc++);
+    const uint16_t instance_reg = rD;
+    RawInstance* instance = reinterpret_cast<RawInstance*>(FP[instance_reg]);
+    FP[rA] = reinterpret_cast<RawObject**>(instance->ptr())[offset_in_words];
+    DISPATCH();
+  }
+
+  {
     BYTECODE(LoadUntagged, A_B_C);
     const uint16_t instance_reg = rB;
     const uint16_t offset_in_words = rC;
     RawInstance* instance = reinterpret_cast<RawInstance*>(FP[instance_reg]);
     FP[rA] = reinterpret_cast<RawObject**>(instance)[offset_in_words];
     DISPATCH();
   }
 
   {
     BYTECODE(LoadFieldTOS, A_D);
@@ skipping 1051 matching lines @@
   pc_ = pc;
   special_[kExceptionSpecialIndex] = raw_exception;
   special_[kStacktraceSpecialIndex] = raw_stacktrace;
   buf->Longjmp();
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC