The subtarget in MipsTargetLowering isn't going to change and
so doesn't need to be a pointer, but a reference.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213422 91177308-0d34-0410-b5e6-96231b3b80d8
Make InstrInfo depend only upon the Subtarget getting passed in
rather than the TargetMachine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213425 91177308-0d34-0410-b5e6-96231b3b80d8
In preparation for replacing the whole subtarget on the target machine,
have target lowering take the subtarget explicitly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213426 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] 32-bit ELF PIC support

This adds initial support for PPC32 ELF PIC (Position Independent Code; the
-fPIC variety), thus rectifying a long-standing deficiency in the PowerPC
backend.

Patch by Justin Hibbits!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213427 91177308-0d34-0410-b5e6-96231b3b80d8
FrameLowering depends only upon the Subtarget, so only take a subtarget
during initialization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213429 91177308-0d34-0410-b5e6-96231b3b80d8
Fundamentally change the MipsSubtarget replacement machinery:

a) Move the replacement level decision to the target machine.
b) Create additional subtargets at the TargetMachine level to
   cache and make replacement easy.
c) Make the mips16 features obvious.
d) Remove the override logic as it no longer does anything.
e) Have MipsModuleDAGToDAGISel take only the target machine.
f) Have the constant islands pass grab the current subtarget
   from the MachineFunction (via the TargetMachine) instead
   of caching it.
g) Unconditionally initialize TLOF.
h) Remove the old complicated subtarget based resetting and
   replace it with simple conditionals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213430 91177308-0d34-0410-b5e6-96231b3b80d8