[coreboot-gerrit] Change in coreboot[master]: [TEST] Add support for link time optimization

[Jacob Garber (Code Review)]

Jacob Garber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/38989 )

Change subject: [TEST] Add support for link time optimization
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Patch Set 6:
> Patch Set 6:
>
> I worked around that error with the hack below.

Yes, this is a current limitation of LTO right now. Because the object files are all lumped together into a single unit, all information about where the symbols came from is lost, so EXCLUDE_FILE is unable of excluding the AGESA objects from the illegal_globals check. Tracing where a symbol came from has been implemented in LLVM [0], but I'm not sure if it's on the roadmap for GCC. For now it's probably best to disable LTO when compiling AGESA.

[0]: https://llvm.org/devmtg/2017-10/slides/LTOLinkerScriptsEdlerVonKoch.pdf