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Re: [rfa:symtab] Delete broken "memory mapped objfile cache"



On Nov 4, 2003, at 11:21 AM, Andrew Cagney wrote:


Hello,

(more, somewhat perverse bcache fallout)

The "memory mapped objfile cache" (for want of a better name) is a technique where by GDB creates per-objfile disk backed memory mapped caches that contain the object files symbol information. Its based on the theory that, after each rebuild little is changed, and hence most symbol information can be drawn from an on-disk cache, and re-read from the object file. The lit, it turns out, supports the theory. A typical debugging rebuild changes little in an executable.

So why delete it? As far as I can tell:

- it hasn't worked in >4years
- it hasn't built in >1year
- it isn't tested

I've nothing personal against the the technique. In fact I'd like to see a robust implementation backed by test cases and supporting performance data. However, I strongly object to GDB having to carry around long-ago broken code. By deleting this, we clear the decks for a modern robust implementation (the original code appears to date back to '92).


Actually, apple has it implemented and working.
Maybe they'd like to share?
If so, and they need that code, maybe we should keep it around for just a bit longer.



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