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Re: Apple's implementation of precompiled headers
- To: dewar at gnat dot com
- Subject: Re: Apple's implementation of precompiled headers
- From: Daniel Berlin <dan at cgsoftware dot com>
- Date: Sat, 29 Sep 2001 11:49:08 -0400
- Cc: degger at fhm dot edu, shebs at apple dot com, gcc at gcc dot gnu dot org
- References: <20010929124226.176D6F2BA0@nile.gnat.com>
dewar@gnat.com writes:
> I am amazed that precompiled headers could make a difference for C, it should
> be easily possible to parse and compile C headers faster than you can read
> them from disk.
In actuality, it's not.
This is because expansion to rtl gets counted in the parse cost, and
it's expensive.
With precomp'd headers as serialized trees, you don't need to
re-expand (assuming you serialize DECL_RTL as well).
--
"I hate it when my foot falls asleep during the day because that
means it's going to be up all night.
"-Steven Wright