Object graph visitor: general depth-first search.

runtime/vm/pages.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/pages.h"
 
 #include "platform/assert.h"
 #include "vm/compiler_stats.h"
 #include "vm/gc_marker.h"
 #include "vm/gc_sweeper.h"
@@ skipping 427 matching lines @@
     if (FLAG_log_code_drop) {
       OS::Print("Trying to detach code.\n");
     }
     page_space_controller_.set_last_code_collection_in_us(start);
     return true;
   }
   return false;
 }
 
 
+void PageSpace::WriteProtectCode(bool read_only) {
+  // TODO(koda): Is this flag still useful?
+  if (FLAG_write_protect_code) {
+    HeapPage* current_page = pages_;
+    while (current_page != NULL) {
+      if (current_page->type() == HeapPage::kExecutable) {
+        current_page->WriteProtect(read_only);
+      }
+      current_page = NextPageAnySize(current_page);
+    }
+  }
+}
+
+
 void PageSpace::MarkSweep(bool invoke_api_callbacks) {
   // MarkSweep is not reentrant. Make sure that is the case.
   ASSERT(!sweeping_);
   sweeping_ = true;
   Isolate* isolate = Isolate::Current();
 
   NoHandleScope no_handles(isolate);
 
   if (FLAG_print_free_list_before_gc) {
     OS::Print("Data Freelist (before GC):\n");
     freelist_[HeapPage::kData].Print();
     OS::Print("Executable Freelist (before GC):\n");
     freelist_[HeapPage::kExecutable].Print();
   }
 
   if (FLAG_verify_before_gc) {
     OS::PrintErr("Verifying before MarkSweep...");
     heap_->Verify();
     OS::PrintErr(" done.\n");
   }
 
   const int64_t start = OS::GetCurrentTimeMicros();
 
-  if (FLAG_write_protect_code) {
-    // Make code pages writable.
-    HeapPage* current_page = pages_;
-    while (current_page != NULL) {
-      if (current_page->type() == HeapPage::kExecutable) {
-        current_page->WriteProtect(false);
-      }
-      current_page = NextPageAnySize(current_page);
-    }
-  }
+  // Make code pages writable.
+  WriteProtectCode(false);
 
   // Save old value before GCMarker visits the weak persistent handles.
   SpaceUsage usage_before = usage_;
 
   // Mark all reachable old-gen objects.
   bool collect_code = FLAG_collect_code && ShouldCollectCode();
   GCMarker marker(heap_);
   marker.MarkObjects(isolate, this, invoke_api_callbacks, collect_code);
   usage_.used_in_words = marker.marked_words();
 
@@ skipping 31 matching lines @@
     bool page_in_use = sweeper.SweepLargePage(page);
     if (page_in_use) {
       prev_page = page;
     } else {
       FreeLargePage(page, prev_page);
     }
     // Advance to the next page.
     page = next_page;
   }
 
-  if (FLAG_write_protect_code) {
-    // Make code pages read-only.
-    HeapPage* current_page = pages_;
-    while (current_page != NULL) {
-      if (current_page->type() == HeapPage::kExecutable) {
-        current_page->WriteProtect(true);
-      }
-      current_page = NextPageAnySize(current_page);
-    }
-  }
+  // Make code pages read-only.
+  WriteProtectCode(true);
 
   int64_t end = OS::GetCurrentTimeMicros();
 
   // Record signals for growth control. Include size of external allocations.
   page_space_controller_.EvaluateGarbageCollection(usage_before, usage_,
                                                    start, end);
 
   heap_->RecordTime(kMarkObjects, mid1 - start);
   heap_->RecordTime(kResetFreeLists, mid2 - mid1);
   heap_->RecordTime(kSweepPages, mid3 - mid2);
@@ skipping 132 matching lines @@
     return 0;
   } else {
     ASSERT(total_time >= gc_time);
     int result= static_cast<int>((static_cast<double>(gc_time) /
                              static_cast<double>(total_time)) * 100);
     return result;
   }
 }
 
 }  // namespace dart