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Text File | 1992-02-01 | 5.4 KB | 124 lines

TDHIDE 1.0 - Shrinks TLink debug information
  Copyright (c) 1992, D.J. Murdoch

Syntax:
         TDHIDE filename modulename [modulename ...]
           to delete references to named modules, or
         TDHIDE filename
           to report on all modules, but make no changes

   An extension of .EXE is assumed on the input file.  To modify
  .TDS files, give the extension explicitly.

Examples:

  TDHIDE myprog system
    will hide all the system unit constants and variables.  Some of the
    standard System unit types appear to be built in to TD, so you'll
    still have access to those, but the displays will look funny.

  TDHIDE myprog
    will produce a report listing the modules, the number of symbols
    defined in each, and the amount of space that TDHIDE could recover
    by hiding each of them.

Description:

  Borland's Turbo Pascal has two debugging modes:  debugging within the
  IDE, and external debugging using the Turbo Debugger.  To do allow
  external debugging, it writes debugging information at the end of the
  .EXE file.  This is the same format as is produced by the TLINK
  linker.

  There's one problem with the way TP writes the debug information for
  units.  All interfaced constants and type definitions are written out,
  whether debugging information is on or off for that unit.  This means
  that the symbol table can become quite large; since TD loads it into
  memory when you're debugging, you can run out of memory when debugging
  large programs which use lots of units.  It also means that TD can be
  unnecessarily slow; when a watch variable goes out of scope, TD
  searches the whole table of identifiers before it gives up and
  displays "????", and it does this *every* time you change the
  instruction pointer by executing something.

  TDHIDE is an effort to fix both of these problems.  If you know that
  you'll never need to access the identifiers in a particular module
  (unit), you can run TDHIDE to hide the module.  It will delete all
  symbols from the TLINK symbol table for that module, and will reclaim
  the space those names occupied.

  If you're not sure which module to hide, you can run TDHIDE with the
  second syntax:

     TDHIDE exename

  This will analyze the symbol table for the given program, and report
  on the number of symbols in each module, and the number of bytes which
  could be recovered.

  TDHIDE also works with separate .TDS files, such as those produced by
  "TDSTRIP -s exename".  You just specify the .TDS extension when you
  give the file name, and the rest is automatic.

Limitations and Warnings:

  TDHIDE was written without any documentation on the TLINK debug
  information.  It has been tested on versions 2.08 and 2.09 of the
  debug info (which TP versions 5.5 and 6.0, and TLINK version 3.01
  produce), but may miss some special cases.  Other versions of the
  information probably won't work at all, but I haven't tested them.
  I do know that BC++ uses version 3.x of the debug information, but
  haven't had a chance to experiment enough to know if TDHIDE will work
  there or not.

  The changes TDHIDE makes are irreversible.  If something goes wrong,
  and you want to undo what TDHIDE did, the only way is to recompile or
  relink your program.

  Use of TDHIDE will change the behaviour of TD in certain situations.
  If one unit overrides a definition in one of TP's standard units, and
  TDHIDE is used to hide the override, then TD will use the original
  definition, and even if it doesn't get confused, you probably will.

  TDHIDE could do a much better job of reducing the size of the debug
  information, but it takes a pretty conservative approach.  The TLINK
  symbol table is a mess of pointers.  If I deleted anything from it,
  I'd have to update hundreds or thousands of pointers; I just don't
  think it would be practical to do that without documentation.
  Instead, TDHIDE recovers space by shrinking the variable length
  records containing symbol names.  Effectively, every name is replaced
  by the zero-length name ''.

License:

  TDHIDE is *not* public domain.  It is copyrighted software, and I
  (D.J. Murdoch) own the copyright.  It is, however, "freeware".  I
  grant you a limited license to use this program for personal,
  non-commercial use at no charge.  Commercial, governmental and
  institutional users may evaluate it for a period of 30 days, but
  *must* pay a site license fee of $50 to me if they continue to use it
  beyond that time.  Educational exemptions are available; send me the
  details of your proposed use to apply for one.

  Source code to TDHIDE is available to users who pay the license fee of
  $50.  This is Turbo Pascal 6.0 code, and includes generic units for
  analyzing .EXE files and TLINK debug information, and units for
  managing huge (>64K) objects on the heap, and for extending the heap
  into EMS memory.  It requires Object Professional from TurboPower
  Software to recompile.

  Send license fees to me at the following address:

    D.J. Murdoch
    79 John St. W.
    Waterloo, Ontario, Canada
    N2L 1B7

  Fees may be submitted in Canadian or U.S. dollars.

Warranty:

  TDHIDE comes with no warranty of any kind.  I don't what problems my
  messing about with the TD debug information will cause; I strongly
  recommend that you don't use TDHIDE unless you really need to.