[ios] Preserve bcsymbolmap files when using CocoaPods

[friedbunny]

Bitcode symbol map files (bcsymbolmap) are used in conjunction with dSYMs to symbolicate crashes. CocoaPods doesn't yet automatically preserve bcsymbolmap files when it is installing vendored pods, so this PR stops CocoaPods from discarding these files.

CocoaPods also does not add bcsymbolmap files to an app's xcarchive, so the developer needs to do this themselves, typically as an install-only build script phase — see #8463 (comment) for general instructions.

Related issues

• This partially addresses Partially missing symbols in crash reports #8463, but a full solution will make the inclusion of dSYMs and bcsymbolmaps automatic for all integration methods (or obviate that need).
• Add support for the dSYM for a prebuilt binary. CocoaPods/CocoaPods#1698 is a related-ish upstream issue.
• [build] Package bcsymbolmap files; cleanup packaging script #9613 is where we started packaging bcsymbolmaps with our framework downloads.

/cc @julianrex @1ec5 @akitchen

[julianrex]

Looks good

[friedbunny]

For posterity, I should note that, as a vendored framework (that has no CocoaPods-created target), there’s apparently nothing we can reasonably add to our podspec that would automatically copy bcsymbolmap files into an appropriate build folder. 😢

[friedbunny]

If you were using this podspec and really wanted a copy-paste solution (instead of manually fiddling with build phases in Xcode), you could do this in your app’s Podfile:

target 'YourMainAppTargetName' do
  script_phase :name => "Copy bitcode symbol maps into Products directory",
    :script => "if [ \"$ACTION\" = \"install\" ]; then mdfind -name .bcsymbolmap -onlyin \"${PODS_ROOT}\" | xargs -I{} cp -v {} \"${CONFIGURATION_BUILD_DIR}\"; fi;",
    :execution_position => :after_compile
end

This will create a build script phase that searches for .bcsymbolmap files in your Pods/ folder and then copies them to the build product directory.

[friedbunny]

The CocoaPods team is working on fixing this in 1.7.0 (CocoaPods/CocoaPods#8470), which should eventually obviate the workaround in #12257 (comment).

[winstondu]

@friedbunny , I am using https://github.com/leavez/cocoapods-binary to prebuild my binaries, and I'm having issues with "__hidden" on the obfuscations when I build my app with bitcode. I do happen to do the extra step of saving my bcsymbolmaps in the pods folder with the built framework files, though they don't end up in my final xcArchive?

Your comment seems promising for my situation, though I am still surprised #8470 doesn't already do the trick.