[PATCH] D158641: [AArch64][Android][DRAFT] Fix FMV ifunc resolver usage on old Android APIs.

[Ryan Prichard via Phabricator via cfe-commits]

rprichard added a comment.

> further confirmation if android_get_device_api_level should work from ifunc_resolver

IIRC an ifunc resolver in Bionic can't generally call any functions in libc, including `android_get_device_api_level` or `__system_property_get`, because the ifunc resolver will typically be called before relocations in libc.so have been resolved. I believe an ifunc resolver also can't call `__system_property_get` because the libc.so system properties are initialized by a constructor function, which isn't called until after relocations are applied (`__libc_preinit` -> `__libc_preinit_impl` -> `__libc_init_common` -> `__system_properties_init`).

I suspect Bionic ought to apply relocations to libraries in a bottom-up fashion, so that libc.so is relocated before the executable or shared objects, but I _think_ it's currently top-down. Deferring ifunc relocations until after non-ifunc relocations are applied is a separate problem.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D158641/new/

https://reviews.llvm.org/D158641