[interpreter] Heal closures when bytecode array is gone.

src/mips/builtins-mips.cc

 // Copyright 2012 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_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 965 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(a1);
 
-  // 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.
   __ lw(a0, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
   Label load_debug_bytecode_array, bytecode_array_loaded;
   Register debug_info = kInterpreterBytecodeArrayRegister;
   DCHECK(!debug_info.is(a0));
   __ lw(debug_info, FieldMemOperand(a0, SharedFunctionInfo::kDebugInfoOffset));
   __ Branch(&load_debug_bytecode_array, ne, debug_info,
             Operand(DebugInfo::uninitialized()));
   __ lw(kInterpreterBytecodeArrayRegister,
         FieldMemOperand(a0, SharedFunctionInfo::kFunctionDataOffset));
   __ bind(&bytecode_array_loaded);
 
+  // Check function data field is actually a BytecodeArray object.
+  Label bytecode_array_not_present;
+  __ JumpIfRoot(kInterpreterBytecodeArrayRegister,
+                Heap::kUndefinedValueRootIndex, &bytecode_array_not_present);
   if (FLAG_debug_code) {
-    // Check function data field is actually a BytecodeArray object.
     __ SmiTst(kInterpreterBytecodeArrayRegister, t0);
     __ Assert(ne, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry, t0,
               Operand(zero_reg));
     __ GetObjectType(kInterpreterBytecodeArrayRegister, t0, t0);
     __ Assert(eq, kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry, t0,
               Operand(BYTECODE_ARRAY_TYPE));
   }
 
   // Push new.target, bytecode array and zero for bytecode array offset.
   __ Push(a3, kInterpreterBytecodeArrayRegister, zero_reg);
@@ skipping 44 matching lines @@
   __ Call(at);
 
   // Even though the first bytecode handler was called, we will never return.
   __ Abort(kUnexpectedReturnFromBytecodeHandler);
 
   // Load debug copy of the bytecode array.
   __ bind(&load_debug_bytecode_array);
   __ lw(kInterpreterBytecodeArrayRegister,
         FieldMemOperand(debug_info, DebugInfo::kAbstractCodeIndex));
   __ Branch(&bytecode_array_loaded);
+
+  // 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);
+  __ lw(t0, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
+  __ lw(t0, FieldMemOperand(t0, SharedFunctionInfo::kCodeOffset));
+  __ Addu(t0, t0, Operand(Code::kHeaderSize - kHeapObjectTag));
+  __ sw(t0, FieldMemOperand(a1, JSFunction::kCodeEntryOffset));
+  __ RecordWriteCodeEntryField(a1, t0, t1);
+  __ Jump(t0);
 }
 
 
 void Builtins::Generate_InterpreterExitTrampoline(MacroAssembler* masm) {
   // The return value is in accumulator, which is already in v0.
 
   // Leave the frame (also dropping the register file).
   __ LeaveFrame(StackFrame::JAVA_SCRIPT);
 
   // Drop receiver + arguments and return.
@@ skipping 1782 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS