diff options
| author | serge-sans-paille <sguelton@redhat.com> | 2021-05-11 20:46:58 +0200 |
|---|---|---|
| committer | Tom Stellard <tstellar@redhat.com> | 2021-05-24 21:39:54 -0700 |
| commit | 328a6ec955327c6d56b6bc3478c723dd3cd468ef (patch) | |
| tree | 2ffd8c3e04d7f0b155e7b701ea86f7a745977c03 | |
| parent | 4973ce53ca8abfc14233a3d8b3045673e0e8543c (diff) | |
Force visibility of llvm::Any to externalupstream/llvmorg-12.0.1-rc1llvmorg-12.0.1-rc1
llvm::Any::TypeId::Id relies on the uniqueness of the address of a static
variable defined in a template function. hidden visibility implies vague linkage
for that variable, which does not guarantee the uniqueness of the address across
a binary and a shared library. This totally breaks the implementation of
llvm::Any.
Ideally, setting visibility to llvm::Any::TypeId::Id should be enough,
unfortunately this doesn't work as expected and we lack time (before 12.0.1
release) to understand why setting the visibility to llvm::Any does work.
See https://gcc.gnu.org/wiki/Visibility and
https://gcc.gnu.org/onlinedocs/gcc/Vague-Linkage.html
for more information on that topic.
Differential Revision: https://reviews.llvm.org/D101972
(cherry picked from commit 3d3abc22b3ef189813a3b9061c2a90ba86a32f44)
| -rw-r--r-- | llvm/include/llvm/ADT/Any.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/llvm/include/llvm/ADT/Any.h b/llvm/include/llvm/ADT/Any.h index 0aded628cda4..1e3abca70679 100644 --- a/llvm/include/llvm/ADT/Any.h +++ b/llvm/include/llvm/ADT/Any.h @@ -23,7 +23,12 @@ namespace llvm { -class Any { +class LLVM_EXTERNAL_VISIBILITY Any { + + // The `Typeid<T>::Id` static data member below is a globally unique + // identifier for the type `T`. It is explicitly marked with default + // visibility so that when `-fvisibility=hidden` is used, the loader still + // merges duplicate definitions across DSO boundaries. template <typename T> struct TypeId { static const char Id; }; struct StorageBase { |