[MLton] getText{Start,End} considered harmful

[Wesley W. Terpstra]

On Sun, Sep 28, 2008 at 7:01 PM, Matthew Fluet <fluet at tti-c.org> wrote:
> My guess is that profiling with shared libraries is a bit much to ask. For
> one, you've worked to ensure that multiple ML shared libraries can be used
> within the same executable, but what would it mean for both of them to be
> profiling libraries -- they would both want to use SIGPROF for their own
> purposes.

Yes, this is clear. However, it seems reasonable to expect to profile
one library. The GC_getText{Start,End} were causing segfaults in this
case.

> There are/were other issues with the approach to time profiling:
>  http://mlton.org/pipermail/mlton/2005-November/028283.html
>  http://mlton.org/pipermail/mlton-commit/2005-November/000238.html

Those emails propose to use code-modification for the C codegen and
the labels for the native codegen. I didn't intend to change this.
AFAIK, the C-codegen profiling path is completely unaffected.

> Running some actual benchmarks (e.g., with the hamlet benchmark, as is
> reported in the above messages) provides real evidence; "I imagine..." and
> "I would contend..." are good hypotheses, but are not experiments.

I should probably run some more experiments, yes.