r242520 was reverted in r244313 as the expected behaviour of the alias
attribute in C is that the alias has the same size as the aliasee. However
we can re-introduce adding the size on the alias when the aliasee does not,
from a source code or object perspective, exist as a discrete entity. This
happens when the aliasee is not a symbol, or when that symbol is private.
Differential Revision: http://reviews.llvm.org/D11943
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244752 91177308-0d34-0410-b5e6-96231b3b80d8
Other objects can never reference the MergedGlobals symbol so external linkage
is never needed. Using private instead of internal linkage means the object is
more similar to what it looks like when global merging is not enabled, with
the only difference being that the merged variables are addressed indirectly
relative to the start of the section they are in.
Also add aliases for merged variables with internal linkage, as this also makes
the object be more like what it is when they are not merged.
Differential Revision: http://reviews.llvm.org/D11942
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244615 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts r242520, as it caused pr24379. Also removes part of the test added
by r243874 that checks the size of alias symbols.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244313 91177308-0d34-0410-b5e6-96231b3b80d8
Enabling merging of extern globals appears to be generally either beneficial or
harmless. On some benchmarks suites (on Cortex-M4F, Cortex-A9, and Cortex-A57)
it gives improvements in the 1-5% range, but in the rest the overall effect is
zero.
Differential Revision: http://reviews.llvm.org/D10966
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243874 91177308-0d34-0410-b5e6-96231b3b80d8
