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Disable libLTO tests when libLTO is not built

Authored by dschuff on Dec 13 2016, 4:20 PM.



The current test only checks whether ld64 is available, causing tests
to fail when ld64 is avilable but libLTO is not built.

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dschuff updated this revision to Diff 81324.Dec 13 2016, 4:20 PM
dschuff retitled this revision from to Disable libLTO tests when libLTO is not built.
dschuff updated this object.
dschuff added a reviewer: beanz.
dschuff added a subscriber: llvm-commits.

Is there an LLVM config option that allows to run make check and not have libLTO built?

The background here is that I have an unfortunate bot with an old XCode toolchain, with an ld64 (ld64-236.4) that apparently does not support the -lto_library flag. So when the tests run it tries to use its libLTO (based on llvm 3.4) instead of the just-built libLTO, and it's of course unable to read the bitcode under test. So I thought of using -DLLVM_TOOL_LTO_BUILD=OFF which works, except that the tests still run.

An alternative to checking for the existence of the file is to change llvm/test/ to add to the config the value of LLVM_TOOL_LTO_BUILD, and it would be available directly here.

I don't mind doing it either way; I just noticed that have_ld_plugin_support() does the same thing (checking for the existence of the DSO). Should I switch both of them?

Let see what @beanz thinks. I have a mild preference to use the CMake variable, since in general it is easy to mess up checking the right path and silently disable tests. The CMake variable shields a user from "accidentally" disabling the tests.

That's a good point, and I also just realized that libLTO builds on Linux too, so the 'dylib' extension is a nonstarter. I'll go with the alternative.

dschuff updated this revision to Diff 81333.Dec 13 2016, 5:26 PM
  • Use configuration variables from instead
mehdi_amini accepted this revision.Dec 13 2016, 5:42 PM
mehdi_amini added a reviewer: mehdi_amini.

LGTM. Thanks.

This revision is now accepted and ready to land.Dec 13 2016, 5:42 PM
dschuff updated this revision to Diff 81385.Dec 14 2016, 8:30 AM
dschuff edited edge metadata.
  • Revert gold part of change, just liblto
This revision was automatically updated to reflect the committed changes.

I realized that the gold part of this change was wrong, so I took that part out and landed just the libLTO part for now.
I also am now having second thoughts that the gold part of the change is good, because the condition for whether the gold plugin gets built is nontrivial (it's LLVM_ENABLE_PIC and LLVM_BINUTILS_INCDIR and implicitly LLVM_TOOL_GOLD_BUILD). So maybe just testing for the presence of the DSO is less error-prone than duplicating that logic in the lit file.

Yeah, without a straightforward cmake way of detecting it, it is likely better this way!