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
Fix indentation typo

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195660 91177308-0d34-0410-b5e6-96231b3b80d8
Unrevert r195599 with testcase fix.

I'm not sure how it was checking for the wrong values...
PR18023.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195670 91177308-0d34-0410-b5e6-96231b3b80d8
ARM integrated assembler generates incorrect nop opcode

This patch fixes a bug in the assembler that was causing bad code to
be emitted.  When switching modes in an assembly file (e.g. arm to
thumb mode) we would always emit the opcode from the original mode.

Consider this small example:

$ cat align.s
.code 16
foo:
  add r0, r0
.align 3
  add r0, r0

$ llvm-mc -triple armv7-none-linux align.s -filetype=obj -o t.o
$ llvm-objdump -triple thumbv7 -d t.o
Disassembly of section .text:
foo:
       0:       00 44         add     r0, r0
       2:       00 f0 20 e3   blx #4195904
       6:       00 00         movs    r0, r0
       8:       00 44         add     r0, r0

This shows that we have actually emitted an arm nop (e320f000)
instead of a thumb nop. Unfortunately, this encodes to a thumb
branch which causes bad things to happen when compiling assembly
code with align directives.

The fix is to notify the ARMAsmBackend when we switch mode. The
MCMachOStreamer was already doing this correctly. This patch makes
the same change for the MCElfStreamer.

There is still a bug in the way nops are emitted for alignment
because the MCAlignment fragment does not store the correct mode.
The ARMAsmBackend will emit nops for the last mode it knew about. In
the example above, we still generate an arm nop if we add a `.code
32` to the end of the file.

PR18019


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195677 91177308-0d34-0410-b5e6-96231b3b80d8