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Re: Precompiled headers
On Mon, 3 Nov 2003 12:14:09 -0800 Mike Stump <mrs@apple.com> wrote:
> 12 minutes to 1 second isn't on the horizon. If you want that this
> year, you will either have to work very hard or go someplace else. If
> you want to work on it, the compile server is a natural fit.
I read the pdf and looked at some code. It seems fairly easy to do what I
want, but I have no way to make sure that it works in all cases. You guys
probably know better what parts of code need changes. So I see it as
independent project.
On the other hand, I don't quite understand where does your scepticism come
from. If you invert dependency map, you can find failed dependencies in
time proportional to size of changed code. If no part of source file has to
be rebuilt, you can avoid file operations and just touch the output.
Negative dependencies can be solved by depending on overloaded symbol and
making symbol depend on list of its declarations. Similarly with other
negative dependencies. I am not sure how much does it complicate gcc's
structures.
> I have code in there now for C++ at least that for code that doesn't
> change, can consume and spit it out very fast the second time
> (dependency check plus fprintf speeds). It uses fine grain dependency
> checking and will redo just the parts that have changed or failed the
> dependency check.
I don't see anything about coarse/fine gain checks in the pdf.