[GC] Fix code flushing to use bytecode if it exists.

src/heap/mark-compact.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.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 886 matching lines @@
 // the marking stack.  Instead, we mark them as both marked and overflowed.
 // When the stack is in the overflowed state, objects marked as overflowed
 // have been reached and marked but their children have not been visited yet.
 // After emptying the marking stack, we clear the overflow flag and traverse
 // the heap looking for objects marked as overflowed, push them on the stack,
 // and continue with marking.  This process repeats until all reachable
 // objects have been marked.
 
 void CodeFlusher::ProcessJSFunctionCandidates() {
   Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kCompileLazy);
+  Code* interpreter_entry_trampoline =
+      isolate_->builtins()->builtin(Builtins::kInterpreterEntryTrampoline);
   Object* undefined = isolate_->heap()->undefined_value();
 
   JSFunction* candidate = jsfunction_candidates_head_;
   JSFunction* next_candidate;
   while (candidate != NULL) {
     next_candidate = GetNextCandidate(candidate);
     ClearNextCandidate(candidate, undefined);
 
     SharedFunctionInfo* shared = candidate->shared();
 
     Code* code = shared->code();
     MarkBit code_mark = ObjectMarking::MarkBitFrom(code);
     if (Marking::IsWhite(code_mark)) {
       if (FLAG_trace_code_flushing && shared->is_compiled()) {
         PrintF("[code-flushing clears: ");
         shared->ShortPrint();
         PrintF(" - age: %d]\n", code->GetAge());
       }
       // Always flush the optimized code map if there is one.
       if (!shared->OptimizedCodeMapIsCleared()) {
         shared->ClearOptimizedCodeMap();
       }
-      shared->set_code(lazy_compile);
-      candidate->set_code(lazy_compile);
+      if (shared->HasBytecodeArray()) {
+        shared->set_code(interpreter_entry_trampoline);
+        candidate->set_code(interpreter_entry_trampoline);
+      } else {
+        shared->set_code(lazy_compile);
+        candidate->set_code(lazy_compile);
+      }
     } else {
       DCHECK(Marking::IsBlack(code_mark));
       candidate->set_code(code);
     }
 
     // We are in the middle of a GC cycle so the write barrier in the code
     // setter did not record the slot update and we have to do that manually.
     Address slot = candidate->address() + JSFunction::kCodeEntryOffset;
     Code* target = Code::cast(Code::GetObjectFromEntryAddress(slot));
     isolate_->heap()->mark_compact_collector()->RecordCodeEntrySlot(
         candidate, slot, target);
 
     Object** shared_code_slot =
         HeapObject::RawField(shared, SharedFunctionInfo::kCodeOffset);
     isolate_->heap()->mark_compact_collector()->RecordSlot(
         shared, shared_code_slot, *shared_code_slot);
 
     candidate = next_candidate;
   }
 
   jsfunction_candidates_head_ = NULL;
 }
 
 
 void CodeFlusher::ProcessSharedFunctionInfoCandidates() {
   Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kCompileLazy);
-
+  Code* interpreter_entry_trampoline =
+      isolate_->builtins()->builtin(Builtins::kInterpreterEntryTrampoline);
   SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
   SharedFunctionInfo* next_candidate;
   while (candidate != NULL) {
     next_candidate = GetNextCandidate(candidate);
     ClearNextCandidate(candidate);
 
     Code* code = candidate->code();
     MarkBit code_mark = ObjectMarking::MarkBitFrom(code);
     if (Marking::IsWhite(code_mark)) {
       if (FLAG_trace_code_flushing && candidate->is_compiled()) {
         PrintF("[code-flushing clears: ");
         candidate->ShortPrint();
         PrintF(" - age: %d]\n", code->GetAge());
       }
       // Always flush the optimized code map if there is one.
       if (!candidate->OptimizedCodeMapIsCleared()) {
         candidate->ClearOptimizedCodeMap();
       }
-      candidate->set_code(lazy_compile);
+      if (candidate->HasBytecodeArray()) {
+        candidate->set_code(interpreter_entry_trampoline);
+      } else {
+        candidate->set_code(lazy_compile);
+      }
     }
 
     Object** code_slot =
         HeapObject::RawField(candidate, SharedFunctionInfo::kCodeOffset);
     isolate_->heap()->mark_compact_collector()->RecordSlot(candidate, code_slot,
                                                            *code_slot);
 
     candidate = next_candidate;
   }
 
@@ skipping 3081 matching lines @@
       // The target is always in old space, we don't have to record the slot in
       // the old-to-new remembered set.
       DCHECK(!heap()->InNewSpace(target));
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8