AArch64: Follow-up to r212073

In r212073 I missed a call of `use_begin()` that assumed the wrong
semantics.  It's not clear to me at all what this code does without the
fix, so I'm not sure how to write a testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212075 91177308-0d34-0410-b5e6-96231b3b80d8
Suppress inlining when the block address is taken

Inlining functions with block addresses can cause many problem and requires a
rich infrastructure to support including escape analysis.  At this point the
safest approach to address these problems is by blocking inlining from
happening.

Background:
There have been reports on Ruby segmentation faults triggered by inlining
functions with block addresses like

//Ruby code snippet
vm_exec_core() {
    finish_insn_seq_0 = &&INSN_LABEL_finish;
    INSN_LABEL_finish:
      ;
}

This kind of scenario can also happen when LLVM picks a subset of blocks for
inlining, which is the case with the actual code in the Ruby environment.

LLVM suppresses inlining for such functions when there is an indirect branch.
The attached patch does so even when there is no indirect branch.  Note that
user code like above would not make much sense: using the global for jumping
across function boundaries would be illegal.

Why was there a segfault:

In the snipped above the block with the label is recognized as dead So it is
eliminated. Instead of a block address the cloner stores a constant (sic!) into
the global resulting in the segfault (when the global is used in a goto).

Why had it worked in the past then:

By luck. In older versions vm_exec_core was also inlined but the label address
used was the block label address in vm_exec_core.  So the global jump ended up
in the original function rather than in the caller which accidentally happened
to work.

Test case ./tools/clang/test/CodeGen/indirect-goto.c will fail as a result
of this commit.

rdar://17245966



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212077 91177308-0d34-0410-b5e6-96231b3b80d8
IR: Add a helper to check for LinkOnceODRLinkage

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212078 91177308-0d34-0410-b5e6-96231b3b80d8
GlobalOpt: Handle non-zero offsets for aliases

An alias with an aliasee of a non-zero GEP is not trivially replacable
with it's aliasee.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212079 91177308-0d34-0410-b5e6-96231b3b80d8
Fix .seh_stackalloc 0

seh_stackalloc 0 is not representable in Win64 SEH info, so emitting it
is a bug.

Reviewers: rnk

Differential Revision: http://reviews.llvm.org/D4334

Patch by Vadim Chugunov!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212081 91177308-0d34-0410-b5e6-96231b3b80d8