PPC/s390: [interpreter] Fix self-healing with preserved bytecode.

src/builtins/s390/builtins-s390.cc

Index: src/builtins/s390/builtins-s390.cc
diff --git a/src/builtins/s390/builtins-s390.cc b/src/builtins/s390/builtins-s390.cc
index 4e7b585e32052142e50b48037504111e689c818e..f9aebf935048f77121d58cc380c2bf648a91458c 100644
--- a/src/builtins/s390/builtins-s390.cc
+++ b/src/builtins/s390/builtins-s390.cc
@@ -1081,12 +1081,13 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
            FieldMemOperand(debug_info, DebugInfo::kDebugBytecodeArrayIndex));
   __ bind(&array_done);
 
-  // Check function data field is actually a BytecodeArray object.
-  Label bytecode_array_not_present;
-  __ CompareRoot(kInterpreterBytecodeArrayRegister,
-                 Heap::kUndefinedValueRootIndex);
-  __ beq(&bytecode_array_not_present);
+  // Check whether we should continue to use the interpreter.
+  Label switch_to_different_code_kind;
+  __ LoadP(r2, FieldMemOperand(r2, SharedFunctionInfo::kCodeOffset));
+  __ CmpP(r2, Operand(masm->CodeObject()));  // Self-reference to this code.
+  __ bne(&switch_to_different_code_kind);
 
+  // Check function data field is actually a BytecodeArray object.
   if (FLAG_debug_code) {
     __ TestIfSmi(kInterpreterBytecodeArrayRegister);
     __ Assert(ne, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
@@ -1152,10 +1153,10 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   LeaveInterpreterFrame(masm, r4);
   __ Ret();
 
-  // If the bytecode array is no longer present, then the underlying function
-  // has been switched to a different kind of code and we heal the closure by
-  // switching the code entry field over to the new code object as well.
-  __ bind(&bytecode_array_not_present);
+  // If the shared code is no longer this entry trampoline, then the underlying
+  // function has been switched to a different kind of code and we heal the
+  // closure by switching the code entry field over to the new code as well.
+  __ bind(&switch_to_different_code_kind);
   __ LeaveFrame(StackFrame::JAVA_SCRIPT);
   __ LoadP(r6, FieldMemOperand(r3, JSFunction::kSharedFunctionInfoOffset));
   __ LoadP(r6, FieldMemOperand(r6, SharedFunctionInfo::kCodeOffset));