Minor update to the stack map documentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205513 91177308-0d34-0410-b5e6-96231b3b80d8
ARM64: don't generate __sincos_stret calls unless on MachO

This should fix PR19314.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205514 91177308-0d34-0410-b5e6-96231b3b80d8
Stack map docs. Remove some stray markup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205515 91177308-0d34-0410-b5e6-96231b3b80d8