[PATCH] D34850: [CodeGen] Propagate dllexport to thunks

[Shoaib Meenai via Phabricator via cfe-commits]

smeenai created this revision.

Under Windows Itanium, we need to export virtual and non-virtual thunks
if the functions being thunked are exported. These thunks would
previously inherit their dllexport attribute from the declaration, but
r298330 changed declarations to not have dllexport attributes. We
therefore need to add the dllexport attribute to the definition
ourselves now.


https://reviews.llvm.org/D34850

Files:
  lib/CodeGen/CGVTables.cpp
  test/CodeGenCXX/windows-itanium-dllexport.cpp


Index: test/CodeGenCXX/windows-itanium-dllexport.cpp
===================================================================
--- test/CodeGenCXX/windows-itanium-dllexport.cpp
+++ test/CodeGenCXX/windows-itanium-dllexport.cpp
@@ -53,3 +53,12 @@
 
 // CHECK: declare dllimport {{.*}} @_ZN5outerIcE1fEv
 // CHECK: define {{.*}} @_ZN5outerIcE5inner1fEv
+
+struct base {
+  virtual ~base();
+};
+struct __declspec(dllexport) derived : public virtual base {
+  virtual ~derived() {}
+};
+
+// CHECK: define {{.*}} dllexport {{.*}} @_ZTv0_n12_N7derivedD0Ev
Index: lib/CodeGen/CGVTables.cpp
===================================================================
--- lib/CodeGen/CGVTables.cpp
+++ lib/CodeGen/CGVTables.cpp
@@ -64,6 +64,10 @@
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
   setThunkVisibility(CGM, MD, Thunk, ThunkFn);
 
+  // Propagate dllexport storage.
+  if (MD->hasAttr<DLLExportAttr>())
+    ThunkFn->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
+
   if (CGM.supportsCOMDAT() && ThunkFn->isWeakForLinker())
     ThunkFn->setComdat(CGM.getModule().getOrInsertComdat(ThunkFn->getName()));
 }


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