* fixed: Undefined symbols for architecture arm64 xxxx[checkcast] #589

dkimitsa · 2021-06-08T15:01:26Z

Issue happens when aggressive mode of tree shaker is used.
This caused to opted-out weak methods to be replaced with stubs. If such method refers to class that also was dropped and uses checkcast/ldr wrappers linking will fail as these symbols are in object files that are not included.

The fix: instead of referencing for external symbol weak stub that just throws exception is created.
During linking these weak stubs will be replaced with valid implementation from target files

Issue happens when aggressive mode of tree shaker is used. This caused to opted-out weak methods to be replaced with stubs. If such method refers to class that also was dropped and uses checkcast/ldr wrappers linking will fail as these symbols are in object files that are not included. The fix: instead of referencing for external symbol weak stub that just throws exception is created. During linking these weak stubs will be replaced with valid implementation from target files

As these were root case of [issue](https://gitter.im/MobiVM/robovm?at=60bf27320f247f448ea46e85) Root case: exported symbols were retaining functions that expected to be dropped by dead_strip This issue also caused wrong fix to be merged into MobiVM [master](MobiVM/robovm#589). That caused another set of [issues](https://gitter.im/MobiVM/robovm?at=620934c66e4c1e1c8461d1cf)

Reverted MobiVM#589 as it wasn't fixing the root case but only symptoms. And was introducing another problem reported on [gitter](https://gitter.im/MobiVM/robovm?at=620934c66e4c1e1c8461d1cf) Root case was exported symbol masks `*GAD*` and `*DFP*` in alt-pod configuration for Google Mobile Ads that were keeping trampolins funciton from being eliminated by `dead_strip` Alt-pods were [fixed](dkimitsa/robovm-robopods@b220a4f) and re-deployed as well

* revert of #589 to fix 'duplicate symbol xxx.spfpoffset'

Tom-Ski merged commit 72ce2e2 into MobiVM:master Oct 19, 2021

dkimitsa deleted the dkimitsa_fix/aggressive_tree_shaker_missing_checkcast_ldr branch October 20, 2021 10:54

dkimitsa mentioned this pull request Feb 16, 2022

* revert of #589 to fix 'duplicate symbol xxx.spfpoffset' #626

Merged

Tom-Ski added a commit that referenced this pull request Feb 16, 2022

Merge pull request #626 from dkimitsa/revert/589

f91c48b

* revert of #589 to fix 'duplicate symbol xxx.spfpoffset'

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* fixed: Undefined symbols for architecture arm64 xxxx[checkcast] #589

* fixed: Undefined symbols for architecture arm64 xxxx[checkcast] #589

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dkimitsa commented Jun 8, 2021

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* fixed: Undefined symbols for architecture arm64 xxxx[checkcast] #589

* fixed: Undefined symbols for architecture arm64 xxxx[checkcast] #589

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dkimitsa commented Jun 8, 2021

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