split out an encoder for memri operands, allowing a relocation to be plopped
into the immediate field.  This allows us to encode stuff like this:

        lbz r3, lo16(__ZL4init)(r4)     ; globalopt.cpp:5
                                        ; encoding: [0x88,0x64,A,A]
                                        ;   fixup A - offset: 0, value: lo16(__ZL4init), kind: fixup_ppc_lo16

        stw r3, lo16(__ZL1s)(r5)        ; globalopt.cpp:6
                                        ; encoding: [0x90,0x65,A,A]
                                        ;   fixup A - offset: 0, value: lo16(__ZL1s), kind: fixup_ppc_lo16

With this, we should have a completely function MCCodeEmitter for PPC, wewt.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119134 91177308-0d34-0410-b5e6-96231b3b80d8
Wire up primitive support in the assembler backend for writing .o files
directly on the mac.  This is very early, doesn't support relocations and
has a terrible hack to avoid .machine from being printed, but despite
that it generates an bitwise-identical-to-cctools .o file for stuff like 
this:

  define i32 @test() nounwind { ret i32 42 }

I don't plan to continue pushing this forward, but if anyone else was
interested in doing it, it should be really straight-forward.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119136 91177308-0d34-0410-b5e6-96231b3b80d8
Improve code layout, mostly indentation. 
No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119142 91177308-0d34-0410-b5e6-96231b3b80d8
Fix PR8565.

This moves most of the isUsed logic to the MCSymbol itself. With this we
get a bit more relaxed about allowing definitions after uses: uses that
don't evaluate their argument immediately (jmp foo) are accepted.

ddunbar, this was the smallest compromise I could think of that lets us
accept gcc (and clang!) assembly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119144 91177308-0d34-0410-b5e6-96231b3b80d8
Dovetail with Dan Dunbar's rework of ELFObjectWriter.
Added 2 new subclasses - X86ELFObjectWriter and ARMELFObectWriter.
ARM and X86 require different code for RecordRelocation(), possibly others.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119149 91177308-0d34-0410-b5e6-96231b3b80d8
Change MCExpr::EvaluateAsRelocatableImpl of variables to return the original
variable if recursing fails to simplify it.

Factor AliasedSymbol to be a method of MCSymbol.

Update MCAssembler::EvaluateFixup to match the change in
EvaluateAsRelocatableImpl.

Remove the WeakRefExpr hack, as the object writer now sees the weakref with
no extra effort needed.

Nothing else is using MCTargetExpr, but keep it for now.

Now that the ELF writer sees relocations with aliases, handle

    .weak    foo2
foo2:
    .weak    bar2
    .set    bar2,foo2
    .quad    bar2

the same way gas does and produce a relocation with bar2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119152 91177308-0d34-0410-b5e6-96231b3b80d8
Move PHI tests to phi.ll, out of select.ll.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119153 91177308-0d34-0410-b5e6-96231b3b80d8
Teach InstructionSimplify the trick of skipping incoming phi
values that are equal to the phi itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119161 91177308-0d34-0410-b5e6-96231b3b80d8
-basicaa is no longer the default.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119163 91177308-0d34-0410-b5e6-96231b3b80d8
Nuke redundant encoding bit set.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119164 91177308-0d34-0410-b5e6-96231b3b80d8
Add FIXMEs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119167 91177308-0d34-0410-b5e6-96231b3b80d8
Update examples and documentation to explicitly add basicaa, now that it's
no longer included by default.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119169 91177308-0d34-0410-b5e6-96231b3b80d8
Add correct Thumb2 encodings for mvn and friends.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119170 91177308-0d34-0410-b5e6-96231b3b80d8
Fix compiler warnigns.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119175 91177308-0d34-0410-b5e6-96231b3b80d8
Add Thumb2 encodings for comparison and shift operators.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119176 91177308-0d34-0410-b5e6-96231b3b80d8
ARM LDR_PRE/LDR_POST/STR_PRE/STR_POST (and the *B counterparts) binary encoding.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119180 91177308-0d34-0410-b5e6-96231b3b80d8
When spilling a register defined by an early clobber, make sure that the new
live ranges for the spill register are also defined at the use slot instead of
the normal def slot.

This fixes PR8612 for the inline spiller. A use was being allocated to the same
register as a spilled early clobber def.

This problem exists in all the spillers. A fix for the standard spiller is
forthcoming.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119182 91177308-0d34-0410-b5e6-96231b3b80d8
Fix PR8612 in the standard spiller as well.

The live range of a register defined by an early clobber starts at the use slot,
not the def slot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119183 91177308-0d34-0410-b5e6-96231b3b80d8
Recommit this change and remove the failing part of the test - it didn't
pass in the first place and was masked by earlier failures not warning
and aborting the block.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119184 91177308-0d34-0410-b5e6-96231b3b80d8
Provide Thumb2 encodings for sxtb and friends.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119185 91177308-0d34-0410-b5e6-96231b3b80d8