ARM: Add support for segmented stacks

Patch by Alex Crichton, ILyoan, Luqman Aden and Svetoslav.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205430 91177308-0d34-0410-b5e6-96231b3b80d8
[yaml2obj][ELF] Remove relationship between ELFState
and ContiguousBlobAccumulator classes. Pass ContiguousBlobAccumulator to
the handleSymtabSectionHeader function directly.

No functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205431 91177308-0d34-0410-b5e6-96231b3b80d8
[yaml2obj][ELF] Move section index to the ELFState class.

No functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205432 91177308-0d34-0410-b5e6-96231b3b80d8
[yaml2obj][ELF] Remove unused typedef.

No functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205433 91177308-0d34-0410-b5e6-96231b3b80d8
[yaml2obj][ELF] Convert some static functions into class members to
reduce number of arguments.

No functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205434 91177308-0d34-0410-b5e6-96231b3b80d8
[ARM64][CollectLOH] Remove the link to the radar from the comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205435 91177308-0d34-0410-b5e6-96231b3b80d8