Refactor to make the .bss, .data and .text sections available for other uses.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195653 91177308-0d34-0410-b5e6-96231b3b80d8
Fix .comm and .lcomm on COFF.

These should not use COMDATs. GNU as uses .bss for .lcomm and section 0 for
.comm.

Given

static int a;
int b;

MSVC puts both in .bss. This patch then puts both .comm and .lcomm on .bss. With
this change we agree with gas on .lcomm, are much closer on .comm and clang-cl
matches msvc on the above example.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195654 91177308-0d34-0410-b5e6-96231b3b80d8
ARM: remove special cases for Darwin dynamic-no-pic mode.

These are handled almost identically to static mode (and ELF's global address
materialisation), except that a symbol may have "$non_lazy_ptr" appended. This
can be handled by passing appropriate flags along with the instruction instead
of using entirely separate pseudo-instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195655 91177308-0d34-0410-b5e6-96231b3b80d8