diff --git a/lld/test/wasm/debug-undefined-fs.s b/lld/test/wasm/debug-undefined-fs.s
new file mode 100644
--- /dev/null
+++ b/lld/test/wasm/debug-undefined-fs.s
@@ -0,0 +1,37 @@
+# Verify that we can handle R_WASM_FUNCTION_OFFSET relocations against live but
+# undefined symbols.  Test that the .debug_info and .debug_int sections are
+# generated without error
+#
+# Based on llvm/test/MC/WebAssembly/debuginfo-relocs.s
+#
+# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown -o %t.o %s
+# RUN: wasm-ld --import-undefined %t.o -o %t.wasm
+# RUN: obj2yaml %t.wasm | FileCheck %s
+
+.functype undef () -> ()
+
+bar:
+    .functype bar () -> ()
+    end_function
+
+    .globl _start
+_start:
+    .functype _start () -> ()
+    call bar
+    call undef
+    end_function
+
+.section .debug_int,"",@
+.Ld:
+  .int32 1
+.size .Ld, 4
+
+.section .debug_info,"",@
+    .int32 bar
+    .int32 undef
+    .int32 .Ld
+
+# CHECK:          Name:            .debug_info
+# CHECK-NEXT:     Payload:         02000000FFFFFFFF00000000
+# CHECK:          Name:            .debug_int
+# CHECK-NEXT:     Payload:         '01000000'
diff --git a/lld/wasm/InputFiles.cpp b/lld/wasm/InputFiles.cpp
--- a/lld/wasm/InputFiles.cpp
+++ b/lld/wasm/InputFiles.cpp
@@ -197,6 +197,9 @@
     return getTagSymbol(reloc.Index)->getTagIndex();
   case R_WASM_FUNCTION_OFFSET_I32:
   case R_WASM_FUNCTION_OFFSET_I64: {
+    if (isa<UndefinedFunction>(sym)) {
+      return tombstone ? tombstone : reloc.Addend;
+    }
     auto *f = cast<DefinedFunction>(sym);
     return f->function->getOffset(f->function->getFunctionCodeOffset() +
                                   reloc.Addend);