Merge commit '8c9feb7e13b2' from llvm.org/main into next

Author: git apple-llvm automerger

llvm/include/llvm/CodeGen/MachineLoopInfo.h

@@ -42,7 +42,8 @@ namespace llvm {
 class MachineDominatorTree;
 // Implementation in LoopInfoImpl.h
 class MachineLoop;
-extern template class LoopBase<MachineBasicBlock, MachineLoop>;
+extern template class LLVM_TEMPLATE_ABI
+    LoopBase<MachineBasicBlock, MachineLoop>;
 
 class MachineLoop : public LoopBase<MachineBasicBlock, MachineLoop> {
 public:

llvm/include/llvm/IR/PassManager.h

@@ -657,8 +657,14 @@ class LLVM_TEMPLATE_ABI InnerAnalysisManagerProxy
   AnalysisManagerT *InnerAM;
 };
 
+// NOTE: The LLVM_ABI annotation cannot be used here because MSVC disallows
+// storage-class specifiers on class members outside of the class declaration
+// (C2720). LLVM_ATTRIBUTE_VISIBILITY_DEFAULT only applies to non-Windows
+// targets so it is used instead. Without this annotation, compiling LLVM as a
+// shared library with -fvisibility=hidden using GCC fails to export the symbol
+// even though InnerAnalysisManagerProxy is already annotated with LLVM_ABI.
 template <typename AnalysisManagerT, typename IRUnitT, typename... ExtraArgTs>
-AnalysisKey
+LLVM_ATTRIBUTE_VISIBILITY_DEFAULT AnalysisKey
     InnerAnalysisManagerProxy<AnalysisManagerT, IRUnitT, ExtraArgTs...>::Key;
 
 /// Provide the \c FunctionAnalysisManager to \c Module proxy.