diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2833,8 +2833,19 @@
     return LV;
   }
 
-  if (const auto *FD = dyn_cast<FunctionDecl>(ND))
-    return EmitFunctionDeclLValue(*this, E, FD);
+  if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
+    LValue LV = EmitFunctionDeclLValue(*this, E, FD);
+
+    // Emit debuginfo for the function declaration if the target wants to.
+    if (getContext().getTargetInfo().allowDebugInfoForExternalVar()) {
+      CGDebugInfo *DI = CGM.getModuleDebugInfo();
+      auto *Fn = dyn_cast<llvm::Function>(LV.getPointer(*this));
+      if (DI && Fn)
+        DI->EmitFunctionDecl(FD, FD->getLocation(), T, Fn);
+    }
+
+    return LV;
+  }
 
   // FIXME: While we're emitting a binding from an enclosing scope, all other
   // DeclRefExprs we see should be implicitly treated as if they also refer to
diff --git a/clang/test/CodeGen/debug-info-extern-callback.c b/clang/test/CodeGen/debug-info-extern-callback.c
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/debug-info-extern-callback.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -x c -debug-info-kind=limited -triple bpf-linux-gnu -emit-llvm %s -o - | FileCheck %s
+
+extern int do_work(int);
+long bpf_helper(void *callback_fn);
+long prog() {
+	    return bpf_helper(&do_work);
+}
+
+// CHECK: declare !dbg ![[FUNC:[0-9]+]] i32 @do_work(i32)
+// CHECK: ![[FUNC]] = !DISubprogram(name: "do_work"