On 2/27/20 3:02 PM, David Malcolm wrote:
On Thu, 2020-02-27 at 14:07 -0500, Nicholas Krause wrote:
Greetings All,
After doing some more research it seems that it may be time to
remove
the garbage collector. I'm
aware of the linkage to precompiled headers but even them I think
its
time due to two reasons:
1. The work related to multithreading gcc is working around the
global
state of the collector which
makes scaling less likely in terms of threads. In addition it is
causing unnecessary compilations
in terms of workarounds in this project.
2. Memory usage may be decreased in certain passes due to being able
to
implement memory allocation
at a pass or per pass type level with more knowledge than a generic
garbage collector. I'm aware this
is done for a lot of passes. However it could be done for the other
passes that are linked currently to the
garbage collector.
I'm not sure what memory allocation strategies we want to implement
in
terms of replacing the garbage
collector but I think its time.
Nick, you've sent various emails to this list suggesting big changes to
GCC's codebase (updating from C++98 to C++11 is another one that
springs to mind), but I believe you've yet to send the project an
actual patch for anything.
I did awhile but most of them were bug fixes on bugzilla. Not
sure if any got merged. Most of these days I doing research so
sorry about that. If your not familiar with it my work is here:
https://docs.google.com/document/d/1po_RRgSCtRyYgMHjV0itW8iOzJXpTdHYIpC9gUMjOxk/edit
It's great that you want to help, and that you have ideas about the
high-level architecture of the project, but may I respectfully suggest
you start with something *much* smaller and more concrete? There are
plenty of bugs in BZ that could use attention.
Of course this was to be long term :). Like the C++11 its more to
get others involved in planning for it. The change patch was
small for C++11. The problem really was testing and figuring out
language support which I helped out with.
Very sorry if your misunderstanding me or my work,
Nick
Hope this is constructive
David
On another I'm looking into the issues with PHI nodes and operators
as
to how to lock or decrease global
state there as this seems to be the biggest complication when I've
time.
In addition as Jeff stated we
will also want to encapsulate SSA operands and other SSA related
things
in a series of classes as part of
this.
Regards,
Nick
