Re: Is Java useful for writing (C/C++) compiler

On 20 Apr 2000 01:34:39 -0400,
  Jonathan Barker <jandk@easynet.co.uk> wrote:
>Obviously, performance depends on how often exceptions occur. It takes
>time to unwind the stack, especially in a language like Java or
>C++. We can't simply perform a jump and set the stack pointer... Since
>the stack trace cannot possibly be known at compile-time (except in
>the simplest cases), the run-time library (or VM) must search each
>frame, executing "finally" clauses and finalising objects until it
>finds a handler for the exception.
>
>Thus, if you rely on exceptions for flow of control in a critical loop,
>it is clear that performance will suffer.


Yes. The Modula-3 people recommend to M3 implementors that exceptions can
be as slow as necessary to make the main code as fast as possible. OTOH,
doing it the C way and checking the return value of every function may
slow a critical loop down more than a rare exception would.


Basically, don't use exceptions to implement a heavily used path of control;
instead, use them for unusual ("exceptional") flow of control.


--
David Starner - dstarner98@aasaa.ofe.org
Finger dvdeug@x8b4e53cd.dhcp.okstate.edu for more information.

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