Commit Graph

108 Commits

Author SHA1 Message Date
Teresa Johnson cbf684e6c6 Revert "Resolution-based LTO API."
This reverts commit r278330.

I made a change to the save temps output that is causing issues with the
bots. Didn't realize this because I had older output files sitting on
disk in my test output directory.

llvm-svn: 278331
2016-08-11 13:03:56 +00:00
Teresa Johnson f99573b3ee Resolution-based LTO API.
Summary:
This introduces a resolution-based LTO API. The main advantage of this API over
existing APIs is that it allows the linker to supply a resolution for each
symbol in each object, rather than the combined object as a whole. This will
become increasingly important for use cases such as ThinLTO which require us
to process symbol resolutions in a more complicated way than just adjusting
linkage.

Patch by Peter Collingbourne.

Reviewers: rafael, tejohnson, mehdi_amini

Subscribers: lhames, tejohnson, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D20268

Address review comments

llvm-svn: 278330
2016-08-11 12:56:40 +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 730c82e6b8 ThinLTO: Remove check for multiple modules before applying weak resolutions.
This check is not only unnecessary, it can produce the wrong result. If we
are linking a single module and it has an exported linkonce symbol, we need
to promote to weak in order to avoid PR19901-style problems.

Differential Revision: http://reviews.llvm.org/D21917

llvm-svn: 274722
2016-07-07 01:51:11 +00:00
Benjamin Kramer d3f4c05aea Move instances of std::function.
Or replace with llvm::function_ref if it's never stored. NFC intended.

llvm-svn: 272513
2016-06-12 16:13:55 +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
Teresa Johnson 04c9a2d63d [ThinLTO] Refactor ODR resolution and internalization (NFC)
Move the now index-based ODR resolution and internalization routines out
of ThinLTOCodeGenerator.cpp and into either LTO.cpp (index-based
analysis) or FunctionImport.cpp (index-driven optimizations).
This is to enable usage by other linkers.

llvm-svn: 270698
2016-05-25 14:03:11 +00:00
Teresa Johnson df6edc5277 [ThinLTO] Refactor module loader handling into new LTO file (NFC)
Moved the ModuleLoader and supporting helper loadModuleFromBuffer out of
ThinLTOCodeGenerator and into new LTO.h/LTO.cpp files. This is in
preparation for a patch that will utilize these in the gold-plugin.

Note that there are some other pending patches (D20268 and D20290) that
also plan to refactor common interfaces and functionality into this same
pair of new files.

llvm-svn: 270509
2016-05-23 22:54:06 +00:00