Re: GCC scalability wrt _extra_ large generated C files

[Zack Weinberg <zack at codesourcery dot com>]

Jacques THOMAS <jthomas at cs dot purdue dot edu> writes:

> Hi all,
>
> I have some _extra_ large generated C source file which I would like
> to compile with GCC.
...
> I observe that, as the size of the source file grows, GCC compile time
> does not increase linearly at all. As I have 800k lines of code that I
> can not (easily) split in separate files, it is a problem.
>
> I have already increased the size of list_hash_table to 1M entries in
> gcc/cp/tree.c in order to avoid spending time on growing the hash
> table. That reduces the problem but doesn't solve it ; gcc is still
> far from scalable.

You don't say which version this is.  But you know how to build the
source tree, so can you please get the latest CVS and build it with
profiling enabled, like so:

$ ../path/to/source/configure --enable-languages=c,c++
$ make all-gcc CFLAGS="-g -O2 -profile"

Make sure you have libc_p.a installed before you do this.  Then run
the resulting cc1plus binary against your 800kline input, and post us
the highlights of the gprof output.  (If you don't know how to use
gprof, email me privately and I'll help.)

zw