Revert "Moves the top_ and end_ words of the Scavenger into mutator thread."

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 105 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 AllocateGC(intptr_t size) {
+  uword TryAllocate(intptr_t size) {
     ASSERT(Utils::IsAligned(size, kObjectAlignment));
     ASSERT(heap_ != Dart::vm_isolate()->heap());
-    ASSERT(scavenging_);
+#if defined(DEBUG)
+    if (FLAG_gc_at_alloc && !scavenging_) {
+      Scavenge();
+    }
+#endif
     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);
+    if (remaining < size) {
+      return 0;
+    }
     ASSERT(to_->Contains(result));
     ASSERT((result & kObjectAlignmentMask) == object_alignment_);
+
     top_ += size;
     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());
-#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()));
-    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;
-  }
+  // Accessors to generate code for inlined allocation.
+  uword* TopAddress() { return &top_; }
+  uword* EndAddress() { return &end_; }
+  static intptr_t top_offset() { return OFFSET_OF(Scavenger, top_); }
+  static intptr_t end_offset() { return OFFSET_OF(Scavenger, end_); }
 
   int64_t UsedInWords() const {
     return (top_ - FirstObjectStart()) >> kWordSizeLog2;
   }
   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();
@@ skipping 16 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;
-
  private:
   // Ids for time and data records in Heap::GCStats.
   enum {
     // Time
     kDummyScavengeTime = 0,
     kSafePoint = 1,
     kVisitIsolateRoots = 2,
     kIterateStoreBuffers = 3,
     kProcessToSpace = 4,
     kIterateWeaks = 5,
@@ skipping 42 matching lines @@
     return end_ < to_->end();
   }
 
   void UpdateMaxHeapCapacity();
   void UpdateMaxHeapUsage();
 
   void ProcessWeakReferences();
 
   intptr_t NewSizeInWords(intptr_t old_size_in_words) const;
 
+  // Accessed from generated code.
+  // ** This block of fields must come first! **
+  // For AOT cross-compilation, we rely on these members having the same offsets
+  // in SIMARM(IA32) and ARM, and the same offsets in SIMARM64(X64) and ARM64.
+  // We use only word-sized fields to avoid differences in struct packing on the
+  // different architectures. See also CheckOffsets in dart.cc.
   uword top_;
   uword end_;
 
   SemiSpace* to_;
 
   Heap* heap_;
 
   // A pointer to the first unscanned object.  Scanning completes when
   // this value meets the allocation top.
   uword resolved_top_;
@@ skipping 24 matching lines @@
 
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_SCAVENGER_H_