DMD memory management

[bitwise via Digitalmars-d]

I'm trying to mod dmd, and I'm totally confused about what's goin on.
-some things are allocated with 'new' and some are allocated with  
'mem.malloc'
-most things don't ever seem to be freed
-no RAII is used for cleanup
-no clear ownership of pointers

How does memory get cleaned up? Is it just assumed that the process is  
short-lived, and that memory can just be left dangling until it terminates?

Thanks,
  Bit