diff --git a/src/tools/wasm-merge.cpp b/src/tools/wasm-merge.cpp
index 24615804da1..2197bc27356 100644
--- a/src/tools/wasm-merge.cpp
+++ b/src/tools/wasm-merge.cpp
@@ -697,11 +697,13 @@ Input source maps can be specified by adding an -ism option right after the modu
          "",
          "Write a wasm-split manifest to the specified file. This manifest can "
          "be given to wasm-split to split the merged module along the lines of "
-         "the original modules.",
+         "the original modules. Implies --debuginfo to preserve function names "
+         "in the output module.",
          WasmMergeOption,
          Options::Arguments::One,
-         [&manifestFile](Options* o, const std::string& argument) {
+         [&](Options* o, const std::string& argument) {
            manifestFile = argument;
+           debugInfo = true;
          })
     .add("--rename-export-conflicts",
          "-rec",
diff --git a/test/lit/help/wasm-merge.test b/test/lit/help/wasm-merge.test
index c0c4ee726a1..8c94b13745c 100644
--- a/test/lit/help/wasm-merge.test
+++ b/test/lit/help/wasm-merge.test
@@ -38,7 +38,8 @@
 ;; CHECK-NEXT:                                        specified file. This manifest can be
 ;; CHECK-NEXT:                                        given to wasm-split to split the merged
 ;; CHECK-NEXT:                                        module along the lines of the original
-;; CHECK-NEXT:                                        modules.
+;; CHECK-NEXT:                                        modules. Implies --debuginfo to preserve
+;; CHECK-NEXT:                                        function names in the output module.
 ;; CHECK-NEXT:
 ;; CHECK-NEXT:   --rename-export-conflicts,-rec       Rename exports to avoid conflicts (rather
 ;; CHECK-NEXT:                                        than error)
diff --git a/test/lit/merge/manifest.wat b/test/lit/merge/manifest.wat
index b0d2ef213ad..c93b40cdef9 100644
--- a/test/lit/merge/manifest.wat
+++ b/test/lit/merge/manifest.wat
@@ -1,5 +1,6 @@
-;; RUN: wasm-merge %s first %s.second second %s.third third --output-manifest %t.manifest -S -o %t.wasm
+;; RUN: wasm-merge %s first %s.second second %s.third third --output-manifest %t.manifest -o %t.wasm
 ;; RUN: cat %t.manifest | filecheck %s
+;; RUN: wasm-dis %t.wasm -o - | filecheck %s --check-prefix MERGED
 
 ;; The first module is the primary module and does not appear in the manifest.
 ;; CHECK-NOT:  first
@@ -12,6 +13,30 @@
 ;; CHECK-NEXT: third
 ;; CHECK-NEXT: qux
 
+;; The binary should contain the original function names.
+;; MERGED:      (module
+;; MERGED-NEXT:  (type $0 (func))
+;; MERGED-NEXT:  (import "env" "imported_first" (func $imported_first))
+;; MERGED-NEXT:  (import "env" "imported_second" (func $imported_second))
+;; MERGED-NEXT:  (import "env" "imported_third" (func $imported_third))
+;; MERGED-NEXT:  (export "foo" (func $foo))
+;; MERGED-NEXT:  (export "bar" (func $bar))
+;; MERGED-NEXT:  (export "baz" (func $baz))
+;; MERGED-NEXT:  (export "qux" (func $qux))
+;; MERGED-NEXT:  (func $foo
+;; MERGED-NEXT:   (call $imported_first)
+;; MERGED-NEXT:  )
+;; MERGED-NEXT:  (func $bar
+;; MERGED-NEXT:   (nop)
+;; MERGED-NEXT:  )
+;; MERGED-NEXT:  (func $baz
+;; MERGED-NEXT:   (call $imported_second)
+;; MERGED-NEXT:  )
+;; MERGED-NEXT:  (func $qux
+;; MERGED-NEXT:   (call $imported_third)
+;; MERGED-NEXT:  )
+;; MERGED-NEXT: )
+
 (module
   (import "env" "imported_first" (func $imported_first))
   (func $foo (export "foo")