[cs] Merge in tree-ssa-20020619-merge-20031207

[Mike Stump]

I thought I would include some timing numbers here, since I collected 
them...  Carbon.h is kinda like saying X11.h, but it has more in it, 
around 82-84k lines total.  You can think of the 142x faster number as 
an upper bound on the speedups obtainable from the technology.  In a 
real application, the number is closer to 2x over PCH for a cold build.

Begin forwarded message:

> Below are some benchmarking numbers for:
>
> #include <Carbon.h>
>
> int i;
>
> as the test case.  The compilers used were checking -O2 style 
> compilers.
> The first number is the time for 5 compiles on one command line, the 
> second number, for one compile on the command line.  The below says 
> that for normal C compiles, having 5 on a line is 1.7% faster than 5 
> separate compiles.  For C++, it is 0.5% faster.
>
> For the compile server numbers, the server is started fresh for a 1 
> unit on the command line compile, and reused for the 5 unit run.  
> Again the times given are for these two runs.  For a C server run, it 
> is 6.3x faster when reusing 5 units.  For C++, it is 77.9x faster when 
> reusing.
>
> And then we see times for compiling 50 units on a command line.  And 
> at the end, we see that for C++, hot compiles are around 142x faster.
>
> 	   Normal C compile:
> 	   9.011/1.833
> 	   4.91598472449536279323
> 	   5/4.91598472449536279323
> 	   1.01709022306070358450 x faster with 5 on same line
> 	   For a normal C++ compile:
> 	   13.219/2.658
> 	   4.97328818660647103085
> 	   5/4.97328818660647103085
> 	   1.00537105681216430894 x faster with 5 on same line
> 	   For a C compile server:
> 	   1.464/1.857
> 	   .78836833602584814216
> 	   5/0.78836833602584814216
> 	   6.34221311475409836069 x faster with 5 on same line (total reuse)
> 	   For a C++ compile server:
> 	   0.169/2.632
> 	   .06420972644376899696
> 	   5/0.06420972644376899696
> 	   77.86982248520710059230 x faster with 5 on same line (total reuse)
> 	   C++ compile server speedup is
> 	   12.27802047585817935018 x faster than C compile server speedup.
> 	   Time for 50 C hot compile server compiles:
> 	   41.680
> 	   Time for 50 C++ hot compile server compiles:
> 	   0.930
> 	   C++ compile server is
> 	   41.680/0.930
> 	   44.81720430107526881720 x faster than C compile server.
>
> 	   For C, the server is around
> 	   9.011/5/(41.680/50)
> 	   2.16194817658349328214 x faster than a normal compile.
> 	   For C++, the server is around
> 	   13.219/5/(0.930/50)
> 	   142.13978494623655913978 x faster than a normal compile.