public static unsafe Object CompilerAllocateGenerational
(VTable vtable, Thread currentThread, UIntPtr bytes, uint alignment)
{
VTable.Assert((alignment == 4) ||
((alignment == 8) && (UIntPtr.Size == 8)) ||
((alignment == 8) && (PreHeader.Size == 4)),
"Unsupported object layout");
VTable.Assert(UIntPtr.Size == PreHeader.Size,
"Unsupported preheader size");
VTable.Assert
(Util.IsAligned((uint)PreHeader.Size + (uint)PostHeader.Size,
alignment),
"Unsupported header sizes");
UIntPtr preHeaderAddr =
MixinThread(currentThread).bumpAllocator.allocPtr;
// allocPtr is only needed when alignment needs to be checked. It
// stores the beginning of the region to be allocation including
// a possible alignment token.
UIntPtr allocPtr = UIntPtr.Zero;
if ((alignment == 8) && (UIntPtr.Size == 4))
{
allocPtr = preHeaderAddr;
preHeaderAddr = Util.Pad(preHeaderAddr, (UIntPtr)alignment);
}
UIntPtr bound = preHeaderAddr + bytes;
UIntPtr limitPtr =
MixinThread(currentThread).bumpAllocator.zeroedLimit;
if (bound <= limitPtr)
{
if ((alignment == 8) && (UIntPtr.Size == 4))
{
// Store alignment token at allocPtr. This will be where an
// alignment token should go if 'preHeaderAddr' was
// bumped...
Allocator.WriteAlignment(allocPtr);
// ... or the alignment token is where the object header
// should be. This code zeroes the object header regardless
// and avoids a branch in this fast path.
*(UIntPtr *)preHeaderAddr = UIntPtr.Zero;
}
MixinThread(currentThread).bumpAllocator.allocPtr = bound;
UIntPtr objAddr = preHeaderAddr + PreHeader.Size;
Object obj = Magic.fromAddress(objAddr);
obj.vtable = vtable;
return(obj);
}
return(GC.AllocateObjectNoInline(vtable, currentThread));
}