Makes new space iterable by filling up the mutator's TLAB

runtime/vm/scavenger.h

 // 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.
 
 #ifndef RUNTIME_VM_SCAVENGER_H_
 #define RUNTIME_VM_SCAVENGER_H_
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/dart.h"
@@ skipping 103 matching lines @@
   ~Scavenger();
 
   // Check whether this Scavenger contains this address.
   // During scavenging both the to and from spaces contain "legal" objects.
   // During a scavenge this function only returns true for addresses that will
   // be part of the surviving objects.
   bool Contains(uword addr) const { return to_->Contains(addr); }
 
   RawObject* FindObject(FindObjectVisitor* visitor) const;
 
+  uword TryAllocateNewTLAB(Thread* thread, intptr_t size) {
+    ASSERT(Utils::IsAligned(size, kObjectAlignment));
+    ASSERT(heap_ != Dart::vm_isolate()->heap());
+    ASSERT(!scavenging_);
+    uword result = top_;
+    intptr_t remaining = end_ - top_;
+    if (remaining < size) {
+      return 0;
+    }
+    ASSERT(to_->Contains(result));
+    ASSERT((result & kObjectAlignmentMask) == object_alignment_);
+    top_ += size;
+    ASSERT(to_->Contains(top_) || (top_ == to_->end()));
+    ASSERT(result < top_);
+    thread->set_top(result);
+    thread->set_end(top_);
+    return result;
+  }
+
   uword AllocateGC(intptr_t size) {
     ASSERT(Utils::IsAligned(size, kObjectAlignment));
     ASSERT(heap_ != Dart::vm_isolate()->heap());
     ASSERT(scavenging_);
     uword result = top_;
     intptr_t remaining = end_ - top_;
 
     // This allocation happens only in GC and only when copying objects to
     // the new to_ space. It must succeed.
     ASSERT(size <= remaining);
     ASSERT(to_->Contains(result));
     ASSERT((result & kObjectAlignmentMask) == object_alignment_);
     top_ += size;
-    ASSERT(to_->Contains(top_) || (top_ == to_->end()));
+    ASSERT((to_->Contains(top_)) || (top_ == to_->end()));
     return result;
   }
 
   uword TryAllocateInTLAB(Thread* thread, intptr_t size) {
     ASSERT(Utils::IsAligned(size, kObjectAlignment));
     ASSERT(heap_ != Dart::vm_isolate()->heap());
     ASSERT(thread->IsMutatorThread());
     ASSERT(thread->isolate()->IsMutatorThreadScheduled());
+    ASSERT(thread->top() <= top_);
+    ASSERT((thread->end() == 0) || (thread->end() == top_));
 #if defined(DEBUG)
     if (FLAG_gc_at_alloc) {
       ASSERT(!scavenging_);
       Scavenge();
     }
 #endif
     uword top = thread->top();
     uword end = thread->end();
     uword result = top;
     intptr_t remaining = end - top;
     if (remaining < size) {
       return 0;
     }
     ASSERT(to_->Contains(result));
     ASSERT((result & kObjectAlignmentMask) == object_alignment_);
     top += size;
-    ASSERT(to_->Contains(top) || (top == to_->end()));
+    ASSERT((to_->Contains(top)) || (top == to_->end()));
     thread->set_top(top);
     return result;
   }
 
   // Collect the garbage in this scavenger.
   void Scavenge();
   void Scavenge(bool invoke_api_callbacks);
 
   // Promote all live objects.
   void Evacuate();
 
   uword top() { return top_; }
   uword end() { return end_; }
 
   void set_top(uword value) { top_ = value; }
   void set_end(uword value) {
     ASSERT(to_->end() == value);
     end_ = value;
   }
 
-  int64_t UsedInWords() const {
-    return (top_ - FirstObjectStart()) >> kWordSizeLog2;
-  }
+  int64_t UsedInWords() const;
   int64_t CapacityInWords() const { return to_->size_in_words(); }
   int64_t ExternalInWords() const { return external_size_ >> kWordSizeLog2; }
   SpaceUsage GetCurrentUsage() const {
     SpaceUsage usage;
     usage.used_in_words = UsedInWords();
     usage.capacity_in_words = CapacityInWords();
     usage.external_in_words = ExternalInWords();
     return usage;
   }
 
@@ skipping 12 matching lines @@
 
   intptr_t collections() const { return collections_; }
 
 #ifndef PRODUCT
   void PrintToJSONObject(JSONObject* object) const;
 #endif  // !PRODUCT
 
   void AllocateExternal(intptr_t size);
   void FreeExternal(intptr_t size);
 
-  void FlushTLS() const;
+  uword FlushTLS() const;
+  void UnflushTLS(uword value) const;
+  uword FirstObjectStart() const { return to_->start() | object_alignment_; }
 
  private:
   // Ids for time and data records in Heap::GCStats.
   enum {
     // Time
     kDummyScavengeTime = 0,
     kSafePoint = 1,
     kVisitIsolateRoots = 2,
     kIterateStoreBuffers = 3,
     kProcessToSpace = 4,
     kIterateWeaks = 5,
     // Data
     kStoreBufferEntries = 0,
     kDataUnused1 = 1,
     kDataUnused2 = 2,
     kToKBAfterStoreBuffer = 3
   };
 
-  uword FirstObjectStart() const { return to_->start() | object_alignment_; }
   SemiSpace* Prologue(Isolate* isolate, bool invoke_api_callbacks);
   void IterateStoreBuffers(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateObjectIdTable(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateRoots(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateWeakProperties(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateWeakReferences(Isolate* isolate, ScavengerVisitor* visitor);
   void IterateWeakRoots(Isolate* isolate, HandleVisitor* visitor);
   void ProcessToSpace(ScavengerVisitor* visitor);
   void EnqueueWeakProperty(RawWeakProperty* raw_weak);
   uword ProcessWeakProperty(RawWeakProperty* raw_weak,
@@ skipping 68 matching lines @@
 
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_SCAVENGER_H_