1 files changed, 26 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
index f0cf5581ba8..d7c75049404 100644
--- a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
+++ b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
@@ -841,17 +841,35 @@ bool DevirtIndex::tryFindVirtualCallTargets(
     std::vector<ValueInfo> &TargetsForSlot, const TypeIdCompatibleVtableInfo TIdInfo,
     uint64_t ByteOffset) {
   for (const TypeIdOffsetVtableInfo P : TIdInfo) {
-    // VTable initializer should have only one summary, or all copies must be
-    // linkonce/weak ODR.
+    // Ensure that we have at most one external linkage vtable initializer.
     assert(P.VTableVI.getSummaryList().size() == 1 ||
-           llvm::all_of(
+           llvm::count_if(
                P.VTableVI.getSummaryList(),
                [&](const std::unique_ptr<GlobalValueSummary> &Summary) {
-                 return GlobalValue::isLinkOnceODRLinkage(Summary->linkage()) ||
-                        GlobalValue::isWeakODRLinkage(Summary->linkage());
-               }));
-    const auto *VS = cast<GlobalVarSummary>(P.VTableVI.getSummaryList()[0].get());
-    if (!P.VTableVI.getSummaryList()[0]->isLive())
+                 return GlobalValue::isExternalLinkage(Summary->linkage());
+               }) <= 1);
+    // Find the first non-available_externally linkage vtable initializer.
+    // We can have multiple available_externally, linkonce_odr and weak_odr
+    // vtable initializers, however we want to skip available_externally as they
+    // do not have type metadata attached, and therefore the summary will not
+    // contain any vtable functions.
+    //
+    // Also, handle the case of same-named local Vtables with the same path
+    // and therefore the same GUID. This can happen if there isn't enough
+    // distinguishing path when compiling the source file. In that case we
+    // conservatively return false early.
+    const GlobalVarSummary *VS = nullptr;
+    bool LocalFound = false;
+    for (auto &S : P.VTableVI.getSummaryList()) {
+      if (GlobalValue::isLocalLinkage(S->linkage())) {
+        if (LocalFound)
+          return false;
+        LocalFound = true;
+      }
+      if (!GlobalValue::isAvailableExternallyLinkage(S->linkage()))
+        VS = cast<GlobalVarSummary>(S.get());
+    }
+    if (!VS->isLive())
       continue;
     for (auto VTP : VS->vTableFuncs()) {
       if (VTP.VTableOffset != P.AddressPointOffset + ByteOffset)