Commit Graph

2 Commits

Author SHA1 Message Date
Peter Smith 3c73a41128 [ELF] Optimize Arm PLT sequences
A more efficient PLT sequence can be used when the distance between the
.plt and the end of the .plt.got is less than 128 Megabytes, which is
frequently true. We fall back to the old sequence when the offset is larger
than 128 Megabytes. This gives us an alternative to forcing the longer
entries with --long-plt as we gracefully fall back to it as needed. 

See ELF for the ARM Architecture Appendix A for details of the PLT sequence.

Differential Revision: https://reviews.llvm.org/D41246

llvm-svn: 320987
2017-12-18 14:46:27 +00:00
Peter Smith 6c9df3fce5 [ELF] Add support for multiple passes to createThunks()
This change allows Thunks to be added on multiple passes. To do this we must
merge only the thunks added in each pass, and deal with thunks that have
drifted out of range of their callers.

A thunk may end out of range of its caller if enough thunks are added in
between the caller and the thunk. To handle this we create another thunk.

Differential Revision: https://reviews.llvm.org/D34692

llvm-svn: 316754
2017-10-27 09:07:10 +00:00