| 889a6758554c27ca4cf93502cfb5dc788cb47990 |
|
03-Sep-2013 |
Rafael Espindola <rafael.espindola@gmail.com> |
Don't emit an available_externally vtable pointing to linkonce_odr funcs.
This fixes pr13124.
From the discussion at
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2012-June/022606.html
we know that we cannot make funcions in a weak_odr vtable also weak_odr. They
should remain linkonce_odr.
The side effect is that we cannot emit a available_externally vtable unless we
also emit a copy of the function. This also has an issue: If codegen is going
to output a function, sema has to mark it used. Given llvm.org/pr9114, it looks
like sema cannot be more aggressive at marking functions used because
of vtables.
This leaves us with a few unpleasant options:
* Marking functions in vtables used if possible. This sounds a bit sloppy, so
we should avoid it.
* Producing available_externally vtables only when all the functions in it are
already used or weak_odr. This would cover cases like
--------------------
struct foo {
virtual ~foo();
};
struct bar : public foo {
virtual void zed();
};
void f() {
foo *x(new bar);
delete x;
}
void g(bar *x) {
x->~bar(); // force the destructor to be used
}
--------------------------
and
----------------------------------
template<typename T>
struct bar {
virtual ~bar();
};
template<typename T>
bar<T>::~bar() {
}
// make the destructor weak_odr instead of linkonce_odr
extern template class bar<int>;
void f() {
bar<int> *x(new bar<int>);
delete x;
}
----------------------------
These look like corner cases, so it is unclear if it is worth it.
* And finally: Just nuke this optimization. That is what this patch implements.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189852 91177308-0d34-0410-b5e6-96231b3b80d8
/external/clang/test/CodeGenCXX/thunks-available-externally.cpp
|
| 93ab6bf534fb6c26563c00f28a8fc5581bb71dfd |
|
15-Aug-2013 |
Stephen Lin <stephenwlin@gmail.com> |
CHECK-LABEL-ify some code gen tests to improve diagnostic experience when tests fail.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188447 91177308-0d34-0410-b5e6-96231b3b80d8
/external/clang/test/CodeGenCXX/thunks-available-externally.cpp
|
| 22df7b17f1b086f4347256406703d259753a0cbf |
|
06-Feb-2011 |
Anders Carlsson <andersca@mac.com> |
Fix self-host; if a thunk already exists and has available_externally linkage, we should change its linkage instead of asserting.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124986 91177308-0d34-0410-b5e6-96231b3b80d8
/external/clang/test/CodeGenCXX/thunks-available-externally.cpp
|
| 14e82fd91c6d5041aa840574143521d244f185cd |
|
06-Feb-2011 |
Anders Carlsson <andersca@mac.com> |
When building with optimizations, emit thunks with available_externally linkage so devirtualized function calls can also be de-thunked.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124984 91177308-0d34-0410-b5e6-96231b3b80d8
/external/clang/test/CodeGenCXX/thunks-available-externally.cpp
|