SuccessChanges

Summary

  1. [Builtins] Fix bug where powerpc builtins specializations didn't remove (details)
  2. Revert "[Builtins] Downgrade duplicate source file warning from a fatal (details)
Commit 8ea148dc0cbff33ac3c80cf4273991465479a01e by dan
[Builtins] Fix bug where powerpc builtins specializations didn't remove
generic implementations.
Summary: Previously the CMake code looked for filepaths of the form
`<arch>/<filename>` as an indication that `<arch>/<filename>` provided a
specialization of a top-level file `<filename>`. For powerpc there was a
bug because the powerpc specialized implementations lived in `ppc/` but
the architectures were `powerpc64` and `powerpc64le` which meant that
CMake was looking for files at `powerpc64/<filename>` and
`powerpc64le/<filename>`.
The result of this is that for powerpc the builtins library contained a
duplicate symbol for `divtc3` because it had the generic implementation
and the specialized version in the built static library.
Although we could just add similar code to what there is for arm (i.e.
compute `${_arch}`) to fix this, this is extremely error prone (until
r375150 no error was raised). Instead this patch takes a different
approach that removes looking for the architecture name entirely.
Instead this patch uses the convention that a source file in a
sub-directory might be a specialization of a generic implementation and
if a source file of the same name (ignoring extension) exists at the
top-level then it is the corresponding generic implementation. This
approach is much simpler because it doesn't require keeping track of
different architecture names.
This convention already existed in repository but previously it was
implicit.  This change makes it explicit.
This patch is motivated by wanting to revert r375162 which worked around
the powerpc bug found when r375150 landed.
Once it lands we should revert r375162.
Reviewers: phosek, beanz, compnerd, shiva0217, amyk, rupprecht, kongyi,
mstorsjo, t.p.northover, weimingz, jroelofs, joerg, sidneym
Subscribers: nemanjai, mgorny, kristof.beyls, jsji, shchenz,
steven.zhang, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D69189
The file was modifiedcompiler-rt/lib/builtins/CMakeLists.txt
Commit 23a33d450b9a426eae7094b16472f8a51fb5488a by dan
Revert "[Builtins] Downgrade duplicate source file warning from a fatal
error to a warning."
This reverts commit dc748816e2aec8941d63f8ad07fb82aff6be8af7.
Now that 8ea148dc0cbff33ac3c80cf4273991465479a01e has landed it should
be safe to turning the warning back into a fatal error.
The file was modifiedcompiler-rt/test/builtins/Unit/lit.cfg.py