Summary:
The old code did eliminate references from and to functions that were
about to be deleted only just before we deleted them. This can cause
references from other functions that are supposed to be deleted to still
exist, depending on the order. If the functions form a strongly
connected component the problem manifests regardless of the order in
which we try to actually delete the functions.
This patch introduces a two step deletion. First we remove all
references and then we delete the function. Note that this only affects
the old call graph. There should not be any functional changes if no old
style call graph was given.
To test this we delete two strongly connected functions instead of one
in an existing test.
Reviewers: hfinkel
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77975
Dead constants might be left when a function is replaced, we can
gracefully handle this case and avoid complexity for the users who would
see an assertion otherwise.
In addition to memory behavior attributes (readonly/writeonly) we now
derive memory location attributes (argmemonly/inaccessiblememonly/...).
The former is part of AAMemoryBehavior and the latter part of
AAMemoryLocation. While they are similar in nature it got messy when
they were put in a single AA. Location attributes for arguments and
floating values will follow later.
Note that both memory attributes kinds can derive readnone. If there are
no accesses AAMemoryBehavior will derive readnone. If there are accesses
but only to stack (=local) locations AAMemoryLocation will derive
readnone.
Reviewed By: uenoku
Differential Revision: https://reviews.llvm.org/D73426
The CallGraphUpdater is a helper that simplifies the process of updating
the call graph, both old and new style, while running an CGSCC pass.
The uses are contained in different commits, e.g. D70767.
More functionality is added as we need it.
Reviewed By: modocache, hfinkel
Differential Revision: https://reviews.llvm.org/D70927
Johannes Doerfert