Do not hard code the leading underscore.

Mangling scheme varies on platform, and prepending an underscore is valid only
on 32-bit x86. Added a method to mangle name to PECOFFLinkingContext and use
it to avoid hard coding mangled names.
Remove hard-coded leading underscore from entry symbol.
PPC: Enable aggressive anti-dependency breaking

Aggressive anti-dependency breaking is enabled by default for all PPC cores.
This provides a general speedup on the P7 and other platforms (among other
factors, the instruction group formation for the non-embedded PPC cores is done
during post-RA scheduling). In order to do this safely, the incompatibility
between uses of the MFOCRF instruction and anti-dependency breaking are
resolved by marking MFOCRF with hasExtraSrcRegAllocReq. As noted in the removed
FIXME, the problem was that MFOCRF's output is sensitive to the identify of the
source register, and always paired with a shift to undo this effect. Because
anti-dependency breaking is unaware of this hidden dependency of the shift
amount on the source register of the MFOCRF instruction, changing that register
must be inhibited.

Two test cases were adjusted: The SjLj test was made more insensitive to
register choices and scheduling; the saveCR test disabled anti-dependency
breaking because part of what it is testing is proper register reuse.
[asan] fully re-implement the FakeStack (use-after-return) to make it faster and async-signal-safe. The implementation is not yet complete (see FIXMEs) but the existing tests pass.
[asan] use xchg instead of CAS in FakeStack::Allocate (5% faster for this case)
[asan] Fix deadlock in stack unwinder on android/x86.

Fixes PR17116.
Patch by 林作健 (manjian2006 at gmail.com).
Fixup for r190409: add dep on LZMA only if CMake is cross-compiling
[asan] hopefully make the FakeStack async-signal safe, enable the related test
[asan] don't lazy-init fake_stack if we only need to check that fake_stack exists (should fix 32-bit builds)
[asan] (part 2) don't lazy-init fake_stack if we only need to check that fake_stack exists (should fix 32-bit builds)
AVX-512: implemented extractelement with variable index.
Added parsing of mask register and "zeroing" semantic, like {%k1} {z}.
[asan] limit the size of the fake stack with a reasonable constant. This fixes a failure when the main thread's stack is considered unlimited (very large).
[ASan] Do not build asan_fake_stack_test.cc on OSX until https://code.google.com/p/address-sanitizer/issues/detail?id=222 is fixed.
Add an instruction deprecation feature to TableGen.

The 'Deprecated' class allows you to specify a SubtargetFeature that the
instruction is deprecated on.

The 'ComplexDeprecationPredicate' class allows you to define a custom
predicate that is called to check for deprecation.
For example:
  ComplexDeprecationPredicate<"MCR">

would mean you would have to define the following function:
  bool getMCRDeprecationInfo(MCInst &MI, MCSubtargetInfo &STI,
                             std::string &Info)

Which returns 'false' for not deprecated, and 'true' for deprecated
and store the warning message in 'Info'.

The MCTargetAsmParser constructor was chaned to take an extra argument of
the MCInstrInfo class, so out-of-tree targets will need to be changed.
LLVM Interpreter: implementation of "insertvalue" and "extractvalue";
undef constatnt for structure and test for these functions.

done by Yuri Veselov (mailto:Yuri.Veselov@intel.com)
LLVM interpreter: added a test for insert- extract- value
Fix the MCTargetAsmParser API change.
[LTO] Fix the LTO tool, after my API breakage.

Thanks to Zonr Chang!
[asan] add a test for use-after-return and exceptions and fix it. Not 100% sure this is a complete fix, will keep looking for harder cases.
Somehow this important part of the patch, where I actually check the Mask,
got lost during my iterations of review.

Thanks to Hal for spotting it!