[MS] Always use base dtors in place of complete/vbase dtors when possible
Summary:
Previously we tried too hard to uphold the fiction that destructor
variants work like they do on Itanium throughout the ABI-neutral parts
of clang. This lead to MS C++ ABI incompatiblities and other bugs. Now,
-mconstructor-aliases will no longer control this ABI detail, and clang
-cc1's LLVM IR output will be this much closer to the clang driver's.
Based on a patch by Zahira Ammarguellat:
https://reviews.llvm.org/D39063
I've tried to move the logic that Zahira added into MicrosoftCXXABI.cpp.
There is only one ABI-specific detail sticking out, and that is in
CodeGenModule::getAddrOfCXXStructor, where we collapse complete dtors to
base dtors in the MS ABI.
This fixes PR32990.
Reviewers: erichkeane, zahiraam, majnemer, rjmccall
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D44505
llvm-svn: 327732
diff --git a/clang/lib/CodeGen/CGCXX.cpp b/clang/lib/CodeGen/CGCXX.cpp
index 738c635..dfae7d5 100644
--- a/clang/lib/CodeGen/CGCXX.cpp
+++ b/clang/lib/CodeGen/CGCXX.cpp
@@ -242,6 +242,11 @@
if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) {
GD = GlobalDecl(CD, toCXXCtorType(Type));
} else {
+ // Always alias equivalent complete destructors to base destructors in the
+ // MS ABI.
+ if (getTarget().getCXXABI().isMicrosoft() &&
+ Type == StructorType::Complete && MD->getParent()->getNumVBases() == 0)
+ Type = StructorType::Base;
GD = GlobalDecl(cast<CXXDestructorDecl>(MD), toCXXDtorType(Type));
}