Add some interfaces to the GC that allow us to reserve space. This is needed...

src/spaces.h

Index: src/spaces.h
===================================================================
--- src/spaces.h	(revision 3575)
+++ src/spaces.h	(working copy)
@@ -305,6 +305,13 @@
   virtual void Print() = 0;
 #endif
 
+  // After calling this we can allocate a certain number of bytes using only
+  // linear allocation (with a LinearAllocationScope and an AlwaysAllocateScope)
+  // without using freelists or causing a GC.  This is used by partial
+  // snapshots.  It returns true of space was reserved or false if a GC is

[Mads Ager (chromium), 2010/01/12 14:17:49]

of space -> if space

+  // needed.
+  virtual bool ReserveSpace(int bytes) = 0;
+
  private:
   AllocationSpace id_;
   Executability executable_;
@@ -887,7 +894,11 @@
   // collection.
   inline Object* MCAllocateRaw(int size_in_bytes);
 
+  virtual bool ReserveSpace(int bytes);
 
+  // Used by ReserveSpace.
+  virtual void PutRestOfCurrentPageOnFreeList(Page* current_page) = 0;
+
   // ---------------------------------------------------------------------------
   // Mark-compact collection support functions
 
@@ -1115,13 +1126,18 @@
     return static_cast<int>(addr - low());
   }
 
-  // If we don't have this here then SemiSpace will be abstract.  However
-  // it should never be called.
+  // If we don't have these here then SemiSpace will be abstract.  However
+  // they should never be called.
   virtual int Size() {
     UNREACHABLE();
     return 0;
   }
 
+  virtual bool ReserveSpace(int bytes) {
+    UNREACHABLE();
+    return false;
+  }
+
   bool is_committed() { return committed_; }
   bool Commit();
   bool Uncommit();
@@ -1345,6 +1361,8 @@
   bool ToSpaceContains(Address a) { return to_space_.Contains(a); }
   bool FromSpaceContains(Address a) { return from_space_.Contains(a); }
 
+  virtual bool ReserveSpace(int bytes);
+
 #ifdef ENABLE_HEAP_PROTECTION
   // Protect/unprotect the space by marking it read-only/writable.
   virtual void Protect();
@@ -1631,6 +1649,8 @@
   // collection.
   virtual void MCCommitRelocationInfo();
 
+  virtual void PutRestOfCurrentPageOnFreeList(Page* current_page);
+
 #ifdef DEBUG
   // Reports statistics for the space
   void ReportStatistics();
@@ -1692,6 +1712,8 @@
   // collection.
   virtual void MCCommitRelocationInfo();
 
+  virtual void PutRestOfCurrentPageOnFreeList(Page* current_page);
+
 #ifdef DEBUG
   // Reports statistic info of the space
   void ReportStatistics();
@@ -1899,6 +1921,11 @@
   // Checks whether the space is empty.
   bool IsEmpty() { return first_chunk_ == NULL; }
 
+  // See the comments for ReserveSpace in the Space class.  This has to be
+  // called after ReserveSpace has been called on the paged spaces, since they
+  // may use some memory, leaving less for large objects.
+  virtual bool ReserveSpace(int bytes);
+
 #ifdef ENABLE_HEAP_PROTECTION
   // Protect/unprotect the space by marking it read-only/writable.
   void Protect();