[BasicBlockSections] Allow mixing of -basic-block-sections with MFS. #117076
Conversation
rlavaee
force-pushed
the
propeller-mfs
branch
from
5d1a7a4
to
32c4db0
Compare
| // Do not split functions when -basic-block-sections=all is specified. | ||
| if (MF.getTarget().getBBSectionsType() == llvm::BasicBlockSection::All) | ||
| return false; |
There was a problem hiding this comment.
Do you intend to support this combination in the future? I think basic block sections is useful for mapping in general beyond it's use in Propeller. If I recall correctly @boomanaiden154 mentioned this type of usage.
There was a problem hiding this comment.
Yes. This applies for AutoFDO builds. The idea is to apply Propeller for functions whose BasicBlockAddressMap structure doesn't change since the profile was collected (even though those functions may have been optimized by autofdo).
There was a problem hiding this comment.
For mapping, we just use the basic block address map rather than basic block sections as we only need to know where blocks are and their size rather than any ability to rearrange/GC them in the linker.
rlavaee
force-pushed
the
propeller-mfs
branch
3 times, most recently
from
7bf6b0d
to
39d8195
Compare
|
Thanks for the quick review! |
rlavaee
force-pushed
the
propeller-mfs
branch
from
39d8195
to
cdb3828
Compare
This PR allows mixing
-basic-block-sectionswith-enable-machine-function-splitter. The strategy is to let-basic-block-sectionstake precedence over functions with profiles.