2 files changed, 49 insertions, 5 deletions
diff --git a/llvm/lib/Support/AArch64AttributeParser.cpp b/llvm/lib/Support/AArch64AttributeParser.cpp
index c675ef2..eed8dba 100644
--- a/llvm/lib/Support/AArch64AttributeParser.cpp
+++ b/llvm/lib/Support/AArch64AttributeParser.cpp
@@ -8,6 +8,7 @@
 //===---------------------------------------------------------------------===//
 
 #include "llvm/Support/AArch64AttributeParser.h"
+#include "llvm/Support/AArch64BuildAttributes.h"
 
 std::vector<llvm::SubsectionAndTagToTagName> &
 llvm::AArch64AttributeParser::returnTagsNamesMap() {
@@ -19,3 +20,29 @@ llvm::AArch64AttributeParser::returnTagsNamesMap() {
       {"aeabi_feature_and_bits", 2, "Tag_Feature_GCS"}};
   return TagsNamesMap;
 }
+
+llvm::AArch64BuildAttrSubsections llvm::extractBuildAttributesSubsections(
+    const llvm::AArch64AttributeParser &Attributes) {
+
+  llvm::AArch64BuildAttrSubsections SubSections;
+  auto GetPauthValue = [&Attributes](unsigned Tag) {
+    return Attributes.getAttributeValue("aeabi_pauthabi", Tag).value_or(0);
+  };
+  SubSections.Pauth.TagPlatform =
+      GetPauthValue(llvm::AArch64BuildAttributes::TAG_PAUTH_PLATFORM);
+  SubSections.Pauth.TagSchema =
+      GetPauthValue(llvm::AArch64BuildAttributes::TAG_PAUTH_SCHEMA);
+
+  auto GetFeatureValue = [&Attributes](unsigned Tag) {
+    return Attributes.getAttributeValue("aeabi_feature_and_bits", Tag)
+        .value_or(0);
+  };
+  SubSections.AndFeatures |=
+      GetFeatureValue(llvm::AArch64BuildAttributes::TAG_FEATURE_BTI);
+  SubSections.AndFeatures |=
+      GetFeatureValue(llvm::AArch64BuildAttributes::TAG_FEATURE_PAC) << 1;
+  SubSections.AndFeatures |=
+      GetFeatureValue(llvm::AArch64BuildAttributes::TAG_FEATURE_GCS) << 2;
+
+  return SubSections;
+}
diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index d5c3cba..8491633 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -68,11 +68,19 @@ template class LLVM_EXPORT_TEMPLATE basic_parser<float>;
 template class LLVM_EXPORT_TEMPLATE basic_parser<std::string>;
 template class LLVM_EXPORT_TEMPLATE basic_parser<char>;
 
-template class opt<unsigned>;
-template class opt<int>;
-template class opt<std::string>;
-template class opt<char>;
-template class opt<bool>;
+#if !(defined(LLVM_ENABLE_LLVM_EXPORT_ANNOTATIONS) && defined(_MSC_VER))
+// Only instantiate opt<std::string> when not building a Windows DLL. When
+// exporting opt<std::string>, MSVC implicitly exports symbols for
+// std::basic_string through transitive inheritance via std::string. These
+// symbols may appear in clients, leading to duplicate symbol conflicts.
+template class LLVM_EXPORT_TEMPLATE opt<std::string>;
+#endif
+
+template class LLVM_EXPORT_TEMPLATE opt<bool>;
+template class LLVM_EXPORT_TEMPLATE opt<char>;
+template class LLVM_EXPORT_TEMPLATE opt<int>;
+template class LLVM_EXPORT_TEMPLATE opt<unsigned>;
+
 } // namespace cl
 } // namespace llvm
 
@@ -95,6 +103,15 @@ void parser<float>::anchor() {}
 void parser<std::string>::anchor() {}
 void parser<char>::anchor() {}
 
+// These anchor functions instantiate opt<T> and reference its virtual
+// destructor to ensure MSVC exports the corresponding vtable and typeinfo when
+// building a Windows DLL. Without an explicit reference, MSVC may omit the
+// instantiation at link time even if it is marked DLL-export.
+void opt_bool_anchor() { opt<bool> anchor{""}; }
+void opt_char_anchor() { opt<char> anchor{""}; }
+void opt_int_anchor() { opt<int> anchor{""}; }
+void opt_unsigned_anchor() { opt<unsigned> anchor{""}; }
+
 //===----------------------------------------------------------------------===//
 
 const static size_t DefaultPad = 2;