MC COFF: Emit the 'b' section flag for .bss sections in GNU assembly

Without this, assembling clang's disassembly would produce an object
file with the IMAGE_SCN_CNT_INITIALIZED_DATA section characteristic
rather than the uninitialized one.  link.exe would warn when merging
comdats with different flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197529 91177308-0d34-0410-b5e6-96231b3b80d8
[DiagnosticPrinter] Use the appropriate method to print a Twine object in a
raw_ostream.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197531 91177308-0d34-0410-b5e6-96231b3b80d8
Support little-endian encodings in the FixedLenDecoderEmitter

The convention used to specify the PowerPC ISA is that bits are numbered in
reverse order (0 is the index of the high bit). To support this "little endian"
encoding convention, CodeEmitterGen will reverse the bit numberings prior to
generating the encoding tables. In order to generate a disassembler,
FixedLenDecoderEmitter needs to do the same.

This moves the bit reversal logic out of CodeEmitterGen and into CodeGenTarget
(where it can be used by both CodeEmitterGen and FixedLenDecoderEmitter). This
is prep work for disassembly support in the PPC backend (which is the only
in-tree user of this little-endian encoding support).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197532 91177308-0d34-0410-b5e6-96231b3b80d8