[interpreter] Merge {OsrPoll} with {Jump} bytecode.

src/interpreter/bytecode-array-writer.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/bytecode-array-writer.h"
 
 #include "src/api.h"
 #include "src/interpreter/bytecode-label.h"
 #include "src/interpreter/bytecode-register.h"
 #include "src/interpreter/constant-array-builder.h"
@@ skipping 339 matching lines @@
     CHECK_LE(current_offset, static_cast<size_t>(kMaxInt));
     // Label has been bound already so this is a backwards jump.
     size_t abs_delta = current_offset - label->offset();
     int delta = -static_cast<int>(abs_delta);
     OperandSize operand_size = Bytecodes::SizeForSignedOperand(delta);
     if (operand_size > OperandSize::kByte) {
       // Adjust for scaling byte prefix for wide jump offset.
       DCHECK_LE(delta, 0);
       delta -= 1;
     }
-    node->set_bytecode(node->bytecode(), delta);
+    if (node->bytecode() == Bytecode::kJumpLoop) {
+      node->set_bytecode(node->bytecode(), delta, node->operand(1));

[rmcilroy, 2016/09/13 10:47:34]

Do we ever have label's bound which don't have Bytecode::kJumpLoop? If not,
could you remove the branch and just make this a DCHECK, otherwise, do you know
where they come from?

[Michael Starzinger, 2016/09/13 12:01:46]

Done. Just the unit-tests, adapted the tests.

+    } else {
+      node->set_bytecode(node->bytecode(), delta);
+    }
   } else {
     // The label has not yet been bound so this is a forward reference

[rmcilroy, 2016/09/13 10:47:34]

Could you add a DCHECK that this is not Bytecode::kJumpLoop

[Michael Starzinger, 2016/09/13 12:01:46]

Done.

     // that will be patched when the label is bound. We create a
     // reservation in the constant pool so the jump can be patched
     // when the label is bound. The reservation means the maximum size
     // of the operand for the constant is known and the jump can
     // be emitted into the bytecode stream with space for the operand.
     unbound_jumps_++;
     label->set_referrer(current_offset);
     OperandSize reserved_operand_size =
         constant_array_builder()->CreateReservedEntry();
     switch (reserved_operand_size) {
@@ skipping 10 matching lines @@
         node->set_bytecode(node->bytecode(), k32BitJumpPlaceholder);
         break;
     }
   }
   EmitBytecode(node);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8