In #99726, `-fptrauth-type-info-vtable-pointer-discrimination` was
introduced, which is intended to enable type and address discrimination
for type_info vtable pointers. However, some codegen logic for actually
enabling address discrimination was missing. This patch addresses the
issue.
Fixes#101716
Reland https://github.com/llvm/llvm-project/pull/75912
The differences of this PR between
https://github.com/llvm/llvm-project/pull/75912 are:
- Fixed a regression in `Decl::isInAnotherModuleUnit()` in DeclBase.cpp
pointed by @mizvekov and add the corresponding test.
- Fixed the regression in windows
https://github.com/llvm/llvm-project/issues/97447. The changes are in
`CodeGenModule::getVTableLinkage` from
`clang/lib/CodeGen/CGVTables.cpp`. According to the feedbacks from MSVC
devs, the linkage of vtables won't affected by modules. So I simply
skipped the case for MSVC.
Given this is more or less fundamental to the use of modules. I hope we
can backport this to 19.x.
This reverts commit 18f3bcbb13ca83d33223b00761d8cddf463e9ffb, 15bb02650e26875c48889053d6a9697444583721 and
99873b35da7ecb905143c8a6b8deca4d4416f1a9.
See the post commit message in
https://github.com/llvm/llvm-project/pull/75912 to see the reasons.
Close https://github.com/llvm/llvm-project/issues/61940.
The root cause is that clang will generate vtable as strong symbol now
even if the corresponding class is defined in other module units. After
I check the wording in Itanium ABI, I find this is not inconsistent.
Itanium ABI 5.2.3
(https://itanium-cxx-abi.github.io/cxx-abi/abi.html#vague-vtable) says:
> The virtual table for a class is emitted in the same object containing
> the definition of its key function, i.e. the first non-pure virtual
> function that is not inline at the point of class definition.
So the current behavior is incorrect. This patch tries to address this.
Also I think we need to do a similar change for MSVC ABI. But I don't
find the formal wording. So I don't address this in this patch.
Reviewed By: rjmccall, iains, dblaikie
Differential Revision: https://reviews.llvm.org/D150023
Breaks check-clang on win and mac, see comments on https://reviews.llvm.org/D150023
This reverts commit d8a36b00d198fdc2ea866ea5da449628db07070f.
Also revert follow-up "[NFC] skip the test modules-vtable.cppm on windows"
This reverts commit baf0b12ca6c624b2a59aa6f2fd0310c72d35ac56.
Close https://github.com/llvm/llvm-project/issues/61940.
The root cause is that clang will generate vtable as strong symbol now
even if the corresponding class is defined in other module units. After
I check the wording in Itanium ABI, I find this is not inconsistent.
Itanium ABI 5.2.3
(https://itanium-cxx-abi.github.io/cxx-abi/abi.html#vague-vtable) says:
> The virtual table for a class is emitted in the same object containing
> the definition of its key function, i.e. the first non-pure virtual
> function that is not inline at the point of class definition.
So the current behavior is incorrect. This patch tries to address this.
Also I think we need to do a similar change for MSVC ABI. But I don't
find the formal wording. So I don't address this in this patch.
Reviewed By: rjmccall, iains, dblaikie
Differential Revision: https://reviews.llvm.org/D150023
