and extern_weak_odr. These are the same as the non-odr versions,
except that they indicate that the global will only be overridden
by an *equivalent* global. In C, a function with weak linkage can
be overridden by a function which behaves completely differently.
This means that IP passes have to skip weak functions, since any
deductions made from the function definition might be wrong, since
the definition could be replaced by something completely different
at link time. This is not allowed in C++, thanks to the ODR
(One-Definition-Rule): if a function is replaced by another at
link-time, then the new function must be the same as the original
function. If a language knows that a function or other global can
only be overridden by an equivalent global, it can give it the
weak_odr linkage type, and the optimizers will understand that it
is alright to make deductions based on the function body. The
code generators on the other hand map weak and weak_odr linkage
to the same thing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66339 91177308-0d34-0410-b5e6-96231b3b80d8
- After GlobalAssign, emit addrspace before global/constant, to follow
the new syntax.
- Eliminate "type void", which is now invalid.
- Fix invalid liblists like [, "foo"].
- Tweak whitespace in a few places.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61706 91177308-0d34-0410-b5e6-96231b3b80d8
and bitcode support for the extractvalue and insertvalue
instructions and constant expressions.
Note that this does not yet include CodeGen support.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51468 91177308-0d34-0410-b5e6-96231b3b80d8
