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

src/builtins/s390/builtins-s390.cc

 // Copyright 2014 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.
 
 #if V8_TARGET_ARCH_S390
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1063 matching lines @@
            FieldMemOperand(r2, SharedFunctionInfo::kDebugInfoOffset));
   // Load original bytecode array or the debug copy.
   __ LoadP(kInterpreterBytecodeArrayRegister,
            FieldMemOperand(r2, SharedFunctionInfo::kFunctionDataOffset));
   __ CmpSmiLiteral(debug_info, DebugInfo::uninitialized(), r0);
   __ beq(&array_done);
   __ LoadP(kInterpreterBytecodeArrayRegister,
            FieldMemOperand(debug_info, DebugInfo::kDebugBytecodeArrayIndex));
   __ bind(&array_done);
 
+  // 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.
-  Label bytecode_array_not_present;
-  __ CompareRoot(kInterpreterBytecodeArrayRegister,
-                 Heap::kUndefinedValueRootIndex);
-  __ beq(&bytecode_array_not_present);
-
   if (FLAG_debug_code) {
     __ TestIfSmi(kInterpreterBytecodeArrayRegister);
     __ Assert(ne, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
     __ CompareObjectType(kInterpreterBytecodeArrayRegister, r2, no_reg,
                          BYTECODE_ARRAY_TYPE);
     __ Assert(eq, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
   }
 
   // Load the initial bytecode offset.
   __ mov(kInterpreterBytecodeOffsetRegister,
@@ skipping 45 matching lines @@
   __ ShiftLeftP(ip, r3, Operand(kPointerSizeLog2));
   __ LoadP(ip, MemOperand(kInterpreterDispatchTableRegister, ip));
   __ Call(ip);
 
   masm->isolate()->heap()->SetInterpreterEntryReturnPCOffset(masm->pc_offset());
 
   // The return value is in r2.
   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));
   __ AddP(r6, r6, Operand(Code::kHeaderSize - kHeapObjectTag));
   __ StoreP(r6, FieldMemOperand(r3, JSFunction::kCodeEntryOffset), r0);
   __ RecordWriteCodeEntryField(r3, r6, r7);
   __ JumpToJSEntry(r6);
 }
 
 void Builtins::Generate_InterpreterMarkBaselineOnReturn(MacroAssembler* masm) {
@@ skipping 1851 matching lines @@
     __ bkpt(0);
   }
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390