issue OPTIMIZE-DEBUG-INFO

[David N Gray <Gray@DSG.csc.ti.com>]

Since no one has raised any objections to this idea, I hereby propose
taking a vote on this at the forthcoming meeting.
  -- David Gray

--
 
Issue:		OPTIMIZE-DEBUG-INFO
References:	CLtL p. 160
Category:	ADDITION
Edit History:   V1  9 Sep 1988, David Gray (initial version)
                V2 19 Sep 1988, David Gray (delete first alternative)
Status:		for sub-committee vote
 
Problem Description:

  The OPTIMIZE declaration provides a way to tell the compiler how important
  various qualities are in order to guide which optimizations are done.
  There is another quality, however, that is not mentioned, but is an
  important consideration for the compiler:  how much information
  should be included in the object code to facilitate debugging.  This
  includes both annotation added to enable a debugger to display more
  information to the user, and also suppression of optimizations that would
  confuse debugging by making it harder to connect the object code with the
  source code.

Proposal OPTIMIZE-DEBUG-INFO:NEW-QUALITY:

  In the description of the OPTIMIZE declaration, add an additional quality
  named DEBUG, described as "ease of debugging".
 
 Rationale:

  Since ease of debugging is an issue that the user will be concerned with,
  and is an issue that the compiler needs to consider, this provides a clear
  way for the user to control the amount of debugging information placed in
  the object module, with DEBUG=0 meaning none and DEBUG=3 meaning "as much
  as possible".
 
 Current Practice:

  No current implementation of this is known.
 
 Cost to implementors:

  All would have to update their handling of OPTIMIZE declarations to accept
  the new quality.
 
 Cost to users:

  One more little feature to learn.  Some problems may result from the
  addition of the symbol DEBUG to the LISP package.
  
 Benefits:

  Provides users a standard way to control the interaction between
  the compiler and debugger, and saves implementors from having to invent
  implementation-dependent solutions.

 Costs of Non-Adoption: 

  Continued confusion about how debug information should be controlled.
 
Discussion:

  Concern has been raised that there is already a problem with the
  non-orthogonality of SPEED, SAFETY, and SPACE that would be made even
  worse with DEBUG added, since users tend to be perplexed by the
  interactions of these qualities.