From 565e907d6f04ca2ef2fecc259124bdb9d0fd080f Mon Sep 17 00:00:00 2001
From: Heejin Ahn <aheejin@gmail.com>
Date: Mon, 27 Oct 2025 14:07:53 +0000
Subject: [PATCH 1/3] [wasm-split] End module names with : in manifests

Suggested by by @sbc100
(https://github.com/emscripten-core/emscripten/pull/25577#discussion_r2456521570).

Currently this supports both module names with a `:` and without it for
backwards compatibility and also to pass the CI.
---
 src/support/istring.h                         | 18 ++++++++++++++++++
 src/tools/wasm-split/wasm-split.cpp           |  3 +++
 test/lit/wasm-split/multi-split.wast.manifest |  6 +++---
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/support/istring.h b/src/support/istring.h
index 7501f85bea7..dad20b8fb00 100644
--- a/src/support/istring.h
+++ b/src/support/istring.h
@@ -88,6 +88,24 @@ struct IString {
     return startsWith(std::string_view(str));
   }
 
+  bool endsWith(std::string_view suffix) const {
+    // TODO: Use C++20 `ends_with`.
+    if (suffix.size() > str.size()) {
+      return false;
+    }
+    return str.substr(str.size() - suffix.size()) == suffix;
+  }
+  bool endsWith(IString str) const { return endsWith(str.str); }
+
+  // Disambiguate for string literals.
+  template<int N> bool endsWith(const char (&str)[N]) const {
+    return endsWith(std::string_view(str));
+  }
+
+  IString substr(size_t pos, size_t len = std::string_view::npos) const {
+    return IString(str.substr(pos, len));
+  }
+
   size_t size() const { return str.size(); }
 };
 
diff --git a/src/tools/wasm-split/wasm-split.cpp b/src/tools/wasm-split/wasm-split.cpp
index 1126c55be66..877e086bd6c 100644
--- a/src/tools/wasm-split/wasm-split.cpp
+++ b/src/tools/wasm-split/wasm-split.cpp
@@ -419,6 +419,9 @@ void multiSplitModule(const WasmSplitOptions& options) {
     }
     Name name = WasmBinaryReader::escape(line);
     if (newSection) {
+      if (name.endsWith(":")) {
+        name = name.substr(0, name.size() - 1);
+      }
       if (moduleNameSet.count(name)) {
         Fatal() << "Module name " << name << " is listed more than once\n";
       }
diff --git a/test/lit/wasm-split/multi-split.wast.manifest b/test/lit/wasm-split/multi-split.wast.manifest
index f6e710feda1..23df277e74c 100644
--- a/test/lit/wasm-split/multi-split.wast.manifest
+++ b/test/lit/wasm-split/multi-split.wast.manifest
@@ -1,8 +1,8 @@
-1
+1:
 A
 
-2
+2:
 B
 
-3
+3:
 C

From d46f5e2fca04694ac575f8520af7e7e02ab1e625 Mon Sep 17 00:00:00 2001
From: Heejin Ahn <aheejin@gmail.com>
Date: Mon, 27 Oct 2025 15:01:40 +0000
Subject: [PATCH 2/3] Update more manifest

---
 test/lit/wasm-split/multi-split-escape-names.wast.manifest | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/lit/wasm-split/multi-split-escape-names.wast.manifest b/test/lit/wasm-split/multi-split-escape-names.wast.manifest
index 23533e6dcf6..8ff81f419c8 100644
--- a/test/lit/wasm-split/multi-split-escape-names.wast.manifest
+++ b/test/lit/wasm-split/multi-split-escape-names.wast.manifest
@@ -1,8 +1,8 @@
-1
+1:
 wasm::Type::getFeatures() const
 
-2
+2:
 wasm::Literal::Literal(std::__2::array<wasm::Literal, 4ul> const&)
 
-3
+3:
 std::operator<<(std::__2::basic_ostream<char, std::__2::char_traits<char>>&, wasm::Module&)

From fdc141af4257bf8ff9027776af1051a8ffa8b5f5 Mon Sep 17 00:00:00 2001
From: Heejin Ahn <aheejin@gmail.com>
Date: Mon, 27 Oct 2025 15:24:42 +0000
Subject: [PATCH 3/3] Error out when module name is empty

---
 src/tools/wasm-split/wasm-split.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/tools/wasm-split/wasm-split.cpp b/src/tools/wasm-split/wasm-split.cpp
index 877e086bd6c..b2e65399774 100644
--- a/src/tools/wasm-split/wasm-split.cpp
+++ b/src/tools/wasm-split/wasm-split.cpp
@@ -421,6 +421,9 @@ void multiSplitModule(const WasmSplitOptions& options) {
     if (newSection) {
       if (name.endsWith(":")) {
         name = name.substr(0, name.size() - 1);
+        if (name.size() == 0) {
+          Fatal() << "Module name is empty\n";
+        }
       }
       if (moduleNameSet.count(name)) {
         Fatal() << "Module name " << name << " is listed more than once\n";