It isn't correct to always remove memprof metadata MIBs from the
original allocation call after inlining.
Let's say we have the following partial call graph:
C D
\ /
v v
B E
| /
v v
A
where A contains an allocation call. If both contexts including B have
the same allocation behavior, the context in the memprof metadata on the
allocation will be pruned, and we will have 2 MIBs with contexts:
A,B and A,E.
Previously, if we inlined A into B we propagate the matching MIBs onto
the inlined allocation call in B' (A,B in this case), and remove it from
the original out of line allocation in A. This is correct if we have a
single round of bottom up inlining.
However, in the compiler we can have multiple invocations of the inliner
pass (e.g. LTO). We may also inline non-bottom up with an alternative
inliner such as the ModuleInliner. In that case, we could end up first
inlining B into C, without having inlined A into B. The call graph then
looks like:
D
|
v
C' B E
\ | /
v v v
A
If we subsequently (perhaps on a later invocation of bottom up inlining)
inline A into B, the previous handling would propagate the memprof MIB
context A,B up into the inlined allocation in B', and remove it from the
original allocation in A. The propagation into B' is fine, however, by
removing it from A's allocation, we no longer reflect the context coming
from C'.
To fix this, simply prevent the removal of MIB from the original
allocation callsites.
Note that the memprof_inline.ll test has some changes to existing
checking to replace "noncold" with "notcold" in the metadata. The
corresponding CHECK was accidentally commented out in the old version
and thus this mistake was not previously detected.
Differential Revision: https://reviews.llvm.org/D140764
Update both memprof and callsite metadata to reflect inlined functions.
For callsite metadata this is simply a concatenation of each cloned
call's call stack with that of the inlined callsite's.
For memprof metadata, each profiled memory info block (MIB) is either
moved to the cloned allocation call or left on the original allocation
call depending on whether its context matches the newly refined call
stack context on the cloned call. We also reapply context trimming
optimizations based on the refined set of contexts on each of the calls
(cloned and original).
Depends on D128142.
Reviewed By: snehasish
Differential Revision: https://reviews.llvm.org/D128143
This reverts commit 0d7f3464ce0ba3a97df73e08ee0acd4e33adbe9b and
commit f9403ca41e5f3dab60cd6e5de26eea65dcab01a4. The latter was
"Profile matching and IR annotation for memprof profiles." and was left
from a bad rebase from a commit already pushed upstream.
Update both memprof and callsite metadata to reflect inlined functions.
For callsite metadata this is simply a concatenation of each cloned
call's call stack with that of the inlined callsite's.
For memprof metadata, each profiled memory info block (MIB) is either
moved to the cloned allocation call or left on the original allocation
call depending on whether its context matches the newly refined call
stack context on the cloned call. We also reapply context trimming
optimizations based on the refined set of contexts on each of the calls
(cloned and original), via utilities in MemoryProfileInfo.
Depends on D128142.
Differential Revision: https://reviews.llvm.org/D128143
