PPC: [interpreter] Heal closures when bytecode array is gone.

src/ppc/builtins-ppc.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_PPC
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 981 matching lines @@
 // frames.h for its layout.
 void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   ProfileEntryHookStub::MaybeCallEntryHook(masm);
 
   // Open a frame scope to indicate that there is a frame on the stack.  The
   // MANUAL indicates that the scope shouldn't actually generate code to set up
   // the frame (that is done below).
   FrameScope frame_scope(masm, StackFrame::MANUAL);
   __ PushStandardFrame(r4);
 
-  // Get the bytecode array from the function object and load the pointer to the
-  // first entry into kInterpreterBytecodeRegister.
+  // Get the bytecode array from the function object (or from the DebugInfo if
+  // it is present) and load it into kInterpreterBytecodeArrayRegister.
   __ LoadP(r3, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
   Label array_done;
   Register debug_info = r5;
   DCHECK(!debug_info.is(r3));
   __ LoadP(debug_info,
            FieldMemOperand(r3, SharedFunctionInfo::kDebugInfoOffset));
   // Load original bytecode array or the debug copy.
   __ LoadP(kInterpreterBytecodeArrayRegister,
            FieldMemOperand(r3, SharedFunctionInfo::kFunctionDataOffset));
   __ CmpSmiLiteral(debug_info, DebugInfo::uninitialized(), r0);
   __ beq(&array_done);
   __ LoadP(kInterpreterBytecodeArrayRegister,
            FieldMemOperand(debug_info, DebugInfo::kAbstractCodeIndex));
   __ 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);
+
   if (FLAG_debug_code) {
-    // Check function data field is actually a BytecodeArray object.
     __ TestIfSmi(kInterpreterBytecodeArrayRegister, r0);
     __ Assert(ne, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
     __ CompareObjectType(kInterpreterBytecodeArrayRegister, r3, no_reg,
                          BYTECODE_ARRAY_TYPE);
     __ Assert(eq, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
   }
 
   // Push new.target, bytecode array and zero for bytecode array offset.
   __ li(r3, Operand::Zero());
   __ Push(r6, kInterpreterBytecodeArrayRegister, r3);
@@ skipping 38 matching lines @@
 
   // Dispatch to the first bytecode handler for the function.
   __ lbzx(r4, MemOperand(kInterpreterBytecodeArrayRegister,
                          kInterpreterBytecodeOffsetRegister));
   __ ShiftLeftImm(ip, r4, Operand(kPointerSizeLog2));
   __ LoadPX(ip, MemOperand(kInterpreterDispatchTableRegister, ip));
   __ Call(ip);
 
   // Even though the first bytecode handler was called, we will never return.
   __ Abort(kUnexpectedReturnFromBytecodeHandler);
+
+  // 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);
+  __ LeaveFrame(StackFrame::JAVA_SCRIPT);
+  __ LoadP(r7, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
+  __ LoadP(r7, FieldMemOperand(r7, SharedFunctionInfo::kCodeOffset));
+  __ addi(r7, r7, Operand(Code::kHeaderSize - kHeapObjectTag));
+  __ StoreP(r7, FieldMemOperand(r4, JSFunction::kCodeEntryOffset), r0);
+  __ RecordWriteCodeEntryField(r4, r7, r8);
+  __ JumpToJSEntry(r7);
 }
 
 
 void Builtins::Generate_InterpreterExitTrampoline(MacroAssembler* masm) {
   // The return value is in accumulator, which is already in r3.
 
   // Leave the frame (also dropping the register file).
   __ LeaveFrame(StackFrame::JAVA_SCRIPT);
 
   // Drop receiver + arguments and return.
@@ skipping 1763 matching lines @@
     __ bkpt(0);
   }
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC