removes section and other symbols in ELF #1220
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We already have llvm-9 installed so there is no reason to install the default llvm also.
though careful many of the options will be just ignored, either by the script or by oasis/omake intergration. Use the new feature immediately in the build-and-test action to enable tests and specify the llvm version (which is for now ignored, but see the next commit).
This is much better than specifying them manually as we did before :) Also, switches back to the static linking with llvm when omake is used.
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The section symbols confuse our symbolization procedure so that at the end we get symbols named as `.text` instead of their real names. To prevent this, we are not emitting anymore relocation information about symbols that are sections, files, objects, and other non-functions. This commit fixes the nightly regression test. The underlying issue is triggered only on modern LLVM (e.g., it is not observable on LLVM 6 and before, but is definitely triggered on 9, not sure about the in between versions).
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Apparently, we were running our tests on LLVM 6, not LLVM 9 as we used to believe. This PR switches to LLVM 9 for running tests and fixes a bug that was not present in LLVM 6 and below (it could be that it appears before 9 though). The problem was in the emission of section symbols from the
eh_framesection, which apparently should represent call frames, so it is not obvious to me why they are tagged as STT_SECTION that is mapped to LLVM's ST_Debug. It is unclear what those symbols encode, but is quite obvious that llvm misinterprets them as at the end of the day we have a bunch of symbols named.textthat hides the real symbols. This PR prevents the emission of such symbols, as well as other symbols, such as file, object, and abi-specific symbols, as we don't really know the interpretation of their fields.This PR also removes the LLVM 6 dependency from our CI file as well as makes changing the llvm version more straightforward when the omake backend is used, e.g.,
Yes, it is awkward but you have to specify both the version and llvm-config path.