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Re: [RFC] type safe trees
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- To: aph at redhat dot com
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 25 Jun 04 08:44:04 EDT
- Subject: Re: [RFC] type safe trees
I'd be a bit nervous about using exceptions to backtrack in the
parser. Such exceptions happen a lot, and the DWARF unwinder is rather
slow for routinely thrown exceptions. Exceptions should be
Note that exceptions are also often the hardest thing to get working
on a new port. GNAT uses exceptions for some things in the front end.
It's not a bootstrap issue to use it for error recovery, but it was
also used at some point for a special case (I forget which) of compiling
code that had no errors.
This caused no end of problems with bootstraps (including most of the issues
involving using mixed versions of GCC and GNAT to start a bootstrap that
occurred when some of the vendors started including GNAT) and has since been
So I strongly agree with you, but not just for efficiency reasons.