Commit Graph

5 Commits

Author SHA1 Message Date
Sean Fertile 4595a915f6 [LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.

Originally commited as r317374, but reverted in r317395 to update some missed
tests.

Differential Revision: https://reviews.llvm.org/D35702

llvm-svn: 317408
2017-11-04 17:04:39 +00:00
Sean Fertile 39770ca0a1 Revert "[LTO][ThinLTO] Use the linker resolutions to mark global values ..."
Changes more tests then expected on one of the build bots.
reverting to investigate.

This reverts https://llvm.org/svn/llvm-project/llvm/trunk@317374

llvm-svn: 317395
2017-11-04 01:54:20 +00:00
Sean Fertile 36528c2a9b [LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.

Differential Revision: https://reviews.llvm.org/D35702

llvm-svn: 317374
2017-11-03 21:45:55 +00:00
Peter Collingbourne 7faa60c406 llvm-lto2: Move the LTO::run() action behind a subcommand.
Move LTO::run() to a "run" subcommand so that we can introduce new subcommands
for testing different parts of the LTO implementation.

This doesn't use llvm::cl subcommands because it doesn't appear to be currently
possible to pass an argument not associated with a subcommand to a subcommand
(e.g. -lto-use-new-pm, -mcpu=yonah).

Differential Revision: https://reviews.llvm.org/D31410

llvm-svn: 299967
2017-04-11 18:12:00 +00:00
Teresa Johnson 185b4ab6d4 [ThinLTO] Stop importing constant global vars as copies in the backend
Summary:
We were doing an optimization in the ThinLTO backends of importing
constant unnamed_addr globals unconditionally as a local copy (regardless
of whether the thin link decided to import them). This should be done in
the thin link instead, so that resulting exported references are marked
and promoted appropriately, but will need a summary enhancement to mark
these variables as constant unnamed_addr.

The function import logic during the thin link was trying to handle
this proactively, by conservatively marking all values referenced in
the initializer lists of exported global variables as also exported.
However, this only handled values referenced directly from the
initializer list of an exported global variable. If the value is itself
a constant unnamed_addr variable, we could end up exporting its
references as well. This caused multiple issues. The first is that the
transitively exported references weren't promoted. Secondly, some could
not be promoted/renamed (e.g. they had a section or other constraint).
recursively, instead of just adding the first level of initializer list
references to the ExportList directly.

Remove this optimization and the associated handling in the function
import backend. SPEC measurements indicate we weren't getting much
from it in any case.

Fixes PR31052.

Reviewers: mehdi_amini

Subscribers: krasin, llvm-commits

Differential Revision: https://reviews.llvm.org/D26880

llvm-svn: 288446
2016-12-02 01:02:30 +00:00