Module handling rewrite

This page describes the planned unit handling rewrite. It is done in a branch in svn, the url of the branch is http://svn.freepascal.org/svn/fpc/branches/unitrw/compiler

While implementing this, it should be taken care of running this in multiple threads in the middle/far future.

Task list

• open file
• Parse header
• Parse uses
• Parse interface
• parse impl. header
• parse impl. uses

• load unit
  • find unit
  • load ppu header
  • load ppu interface
  • load ppu impl.

• write ppu
• write object file

Task queue

• each task gets a two lists: task which must be processed before itself and tasks which depend on itself
• each task class gets a counter each time a new task to process is search, that counter is increased when searching a task to process,
• the queue is walked if a task without empty dependencies is found, it is moved to the end of the queue
• if a task is found with the same number as the current queue walking, the dependencies can't be resolved => error
• if a task with an empty dependencies list is found, it is executed after it is finished, it gets removed from the dependency lists of tasks waiting for it