Enable the instruction printer in HexagonMCTargetDesc

This adds the MCInstPrinter to the LLVMHexagonDesc library and removes
the dependency LLVMHexagonAsmPrinter had on LLVMHexagonDesc. This is
a prerequisite needed by the disassembler.

Phabricator Revision: http://reviews.llvm.org/D5734

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219826 91177308-0d34-0410-b5e6-96231b3b80d8
Correctly handle references to section symbols.

When processing assembly like

.long .text

we were creating a new undefined symbol .text. GAS on the other hand would
handle that as a reference to the .text section.

This patch implements that by creating the section symbols earlier so that
they are visible during asm parsing.

The patch also updates llvm-readobj to print the symbol number in the relocation
dump so that the test can differentiate between two sections with the same name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219829 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Factor out add with immediate emission into a helper function. NFC.

Simplify add with immediate emission by factoring it out into a helper function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219830 91177308-0d34-0410-b5e6-96231b3b80d8
Reapply "[FastISel][AArch64] Add custom lowering for GEPs."

This is mostly a copy of the existing FastISel GEP code, but we have to
duplicate it for AArch64, because otherwise we would bail out even for simple
cases. This is because the standard fastEmit functions don't cover MUL at all
and ADD is lowered very inefficientily.

The original commit had a bug in the add emit logic, which has been fixed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219831 91177308-0d34-0410-b5e6-96231b3b80d8
InstCombine: Narrow switch instructions using known bits.

Truncate the operands of a switch instruction to a narrower type if the upper
bits are known to be all ones or zeros.

rdar://problem/17720004


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219832 91177308-0d34-0410-b5e6-96231b3b80d8