1 files changed, 48 insertions, 0 deletions
diff --git a/include/llvm/DebugInfo/PDB/Native/TpiHashing.h b/include/llvm/DebugInfo/PDB/Native/TpiHashing.h
index c1edec7a26fe..c2996ccf1825 100644
--- a/include/llvm/DebugInfo/PDB/Native/TpiHashing.h
+++ b/include/llvm/DebugInfo/PDB/Native/TpiHashing.h
@@ -18,6 +18,54 @@ namespace pdb {
 
 Expected<uint32_t> hashTypeRecord(const llvm::codeview::CVType &Type);
 
+struct TagRecordHash {
+  explicit TagRecordHash(codeview::ClassRecord CR, uint32_t Full,
+                         uint32_t Forward)
+      : FullRecordHash(Full), ForwardDeclHash(Forward), Class(std::move(CR)) {
+    State = 0;
+  }
+
+  explicit TagRecordHash(codeview::EnumRecord ER, uint32_t Full,
+                         uint32_t Forward)
+      : FullRecordHash(Full), ForwardDeclHash(Forward), Enum(std::move(ER)) {
+    State = 1;
+  }
+
+  explicit TagRecordHash(codeview::UnionRecord UR, uint32_t Full,
+                         uint32_t Forward)
+      : FullRecordHash(Full), ForwardDeclHash(Forward), Union(std::move(UR)) {
+    State = 2;
+  }
+
+  uint32_t FullRecordHash;
+  uint32_t ForwardDeclHash;
+
+  codeview::TagRecord &getRecord() {
+    switch (State) {
+    case 0:
+      return Class;
+    case 1:
+      return Enum;
+    case 2:
+      return Union;
+    }
+    llvm_unreachable("unreachable!");
+  }
+
+private:
+  union {
+    codeview::ClassRecord Class;
+    codeview::EnumRecord Enum;
+    codeview::UnionRecord Union;
+  };
+
+  uint8_t State = 0;
+};
+
+/// Given a CVType referring to a class, structure, union, or enum, compute
+/// the hash of its forward decl and full decl.
+Expected<TagRecordHash> hashTagRecord(const codeview::CVType &Type);
+
 } // end namespace pdb
 } // end namespace llvm