diff --git a/llvm/include/llvm-c/DebugInfo.h b/llvm/include/llvm-c/DebugInfo.h
--- a/llvm/include/llvm-c/DebugInfo.h
+++ b/llvm/include/llvm-c/DebugInfo.h
@@ -226,6 +226,13 @@
  */
 void LLVMDIBuilderFinalize(LLVMDIBuilderRef Builder);
 
+/**
+ * Finalize a specific subprogram.
+ * No new variables may be added to this subprogram afterwards.
+ */
+void LLVMDIBuilderFinalizeSubprogram(LLVMDIBuilderRef Builder,
+                                     LLVMMetadataRef Subprogram);
+
 /**
  * A CompileUnit provides an anchor for all debugging
  * information generated during this instance of compilation.
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -909,6 +909,11 @@
   unwrap(Builder)->finalize();
 }
 
+void LLVMDIBuilderFinalizeSubprogram(LLVMDIBuilderRef Builder,
+                                     LLVMMetadataRef subprogram) {
+  unwrap(Builder)->finalizeSubprogram(unwrapDI<DISubprogram>(subprogram));
+}
+
 LLVMMetadataRef LLVMDIBuilderCreateCompileUnit(
     LLVMDIBuilderRef Builder, LLVMDWARFSourceLanguage Lang,
     LLVMMetadataRef FileRef, const char *Producer, size_t ProducerLen,