Commit Graph

5 Commits

Author SHA1 Message Date
Teresa Johnson 4566c6db87 [ThinLTO] Drop non-prevailing non-ODR weak to declarations
Summary:
Allow non-ODR weak/linkonce non-prevailing copies to be marked
as available_externally in the index. Add support for dropping these to
declarations in the backend.

Reviewers: mehdi_amini, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28806

llvm-svn: 292656
2017-01-20 21:54:58 +00:00
Teresa Johnson 3bc8abdffc [ThinLTO] Correctly resolve linkonce when importing aliasee
Summary:
When we have an aliasee that is linkonce, while we can't convert
the non-prevailing copies to available_externally, we still need to
convert the prevailing copy to weak. If a reference to the aliasee
is exported, not converting a copy to weak will result in undefined
references when the linkonce is removed in its original module.

Add a new test and update existing tests.

Reviewers: mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D26076

llvm-svn: 285512
2016-10-30 05:15:23 +00:00
Peter Collingbourne 73589f321b ThinLTO: Do not take into account whether a definition has multiple copies when promoting.
We currently do not touch a symbol's linkage in the case where a definition
has a single copy. However, this code is effectively unnecessary: either
the definition is not exported, in which case the internalize phase sets
its linkage to internal, or it is exported, in which case we need to promote
linkage to weak. Those two cases are already handled by existing code.

I believe that the only real functional change here is in the case where we
have a single definition which does not prevail (e.g. because the definition
in a native object file prevails). In that case we now lower linkage to
available_externally following the existing code path for that case.

As a result we can remove the isExported function parameter from the
thinLTOResolveWeakForLinkerInIndex function.

Differential Revision: http://reviews.llvm.org/D21883

llvm-svn: 274784
2016-07-07 18:31:51 +00:00
Peter Collingbourne d1d2614ee1 ThinLTO: Add test cases for promote+internalize.
This tests the effect of both promotion and internalization on a module,
and helps show that D21883 is NFC wrt promotion+internalization.

Differential Revision: http://reviews.llvm.org/D21915

llvm-svn: 274699
2016-07-06 22:53:02 +00:00
Teresa Johnson 28c03b56ec [ThinLTO] Resolve LinkOnceAny
Summary:
Ensure we keep prevailing copy of LinkOnceAny by converting it to
WeakAny.

Rename odr_resolution test to the now more appropriate weak_resolution
(weak in the linker sense includes linkonce).

Reviewers: joker.eph

Subscribers: llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D20634

llvm-svn: 270850
2016-05-26 14:16:52 +00:00