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Re: Merging debug-early work?


On 05/08/2015 01:51 AM, Richard Biener wrote:

Did you see if --with-build-config=bootstrap-lto still works?

Just did on x86-64 Linux.  Bootstrap succeeds without any problems.

While doing the LTO work I wondered why you have the late_global_decl
loop in toplev.c:compile_file at all (well, maybe due to the missing one
for global vars output).  At least for function decls we should have covered
everything by that point.

It took a lot of trial and error with Jason reviewing these entry points, to find the right place to place things and not get a slew of unused DIEs created or unhandled (local statics, C++ clones, optimized away symbols, locals, etc etc). I can't remember the details, though I'm sure we discussed it at length when the patches went into the branch.

Perhaps now that adding an unused decl DIE removal pass is a must, we could make the early/late business less efficient but cleaner, and then have the upcoming DIE removal pass clean things up? Ughh...it did take a while to get right without bloating things too much, but I don't doubt there are ways to streamline it further.

Early debug seems to be enforced at finalize-compilation-unit time, but
only for function decls - I wonder why not as well for global vars
(and why the odd !decl_function_context check is there for functions).

IIRC, stuff living in functions were handled through recursion within dwarf2out. I think we would miss local statics, or some such corner case. I invite you to comment things out and see where things fail in the bootstrap/tests :).

Aldy


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