Bugzilla

`dump_syms` is used by `gathersymbols.py` (from https://github.com/marco-c/breakpad-scrape-system-symbols), which is the only tool Mozilla has for the manual scraping of symbols. To work in that context on BigSur, it will need to be able to pull a system library out of the dyld shared cache when it's not present in the file system. It can't do that at present. (I tested with both the `dump_syms` from Google Breakpad and the [Rust one that's currently being used by the Mozilla build infrastructure](https://github.com/mozilla/dump_syms).)

Manual scraping is important. Mozilla does have a system for automated scraping of symbols from Apple updates (minor updates), as they come out. But it misses a *lot* of symbols, so manual scraping is still needed. For the last year or so, I've been the one doing the scraping. I've been sending the symbols I scrape to Marco Castelluccio, who's been uploading them to the symbol server. Without this, the quality of crash stacks on https://crash-stats.mozilla.org/ would have been much worse.

I do understand that the problems discussed in this bug will take a while to fix properly. If nothing else, we need to wait until Python fully supports BigSur. So in the meantime I've found a way to use the `dyld_shared_cache_util` utility to extract binaries from the dyld shared cache into directories that our current tools (`gathersymbols.py`, Python 2.7 and `dump_syms`) can scrape manually. I've sent a bunch of symbols to Marco, which he should be uploading soon to the symbol server.

`dump_syms` is used by `gathersymbols.py` (from https://github.com/marco-c/breakpad-scrape-system-symbols), which is the only tool Mozilla has for the manual scraping of symbols. To work in that context on BigSur, it will need to be able to pull a system library out of the dyld shared cache when it's not present in the file system. It can't do that at present. (I tested with both the `dump_syms` from Google Breakpad and the [Rust one that's currently being used by the Mozilla build infrastructure](https://github.com/mozilla/dump_syms).)

Manual scraping is important. Mozilla does have a system for automated scraping of symbols from Apple updates (minor updates), as they come out. But it misses a *lot* of symbols, so manual scraping is still needed. For the last year or so, I've been the one doing the scraping, each time Apple releases a new minor update for macOS 10.13, 10.14 or 10.15. I've been sending the symbols I scrape to Marco Castelluccio, who's been uploading them to the symbol server. Without this, the quality of crash stacks on https://crash-stats.mozilla.org/ would have been much worse.

I do understand that the problems discussed in this bug will take a while to fix properly. If nothing else, we need to wait until Python fully supports BigSur. So in the meantime I've found a way to use the `dyld_shared_cache_util` utility to extract binaries from the dyld shared cache into directories that our current tools (`gathersymbols.py`, Python 2.7 and `dump_syms`) can scrape manually. I've sent a bunch of symbols to Marco, which he should be uploading soon to the symbol server.