From 474a6209dab82d58c85e749032465b521a5f5a6e Mon Sep 17 00:00:00 2001
From: Piotr Sikora <code@piotrsikora.dev>
Date: Sat, 28 Feb 2026 00:48:56 -0500
Subject: [PATCH] Call __main_void if exported by a plugin.

This is how Rust exports main() function since Rust v1.67.

Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
---
 include/proxy-wasm/wasm.h    | 2 ++
 include/proxy-wasm/wasm_vm.h | 4 ++--
 src/wasm.cc                  | 3 +++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/proxy-wasm/wasm.h b/include/proxy-wasm/wasm.h
index 9b85710bd..00e11f500 100644
--- a/include/proxy-wasm/wasm.h
+++ b/include/proxy-wasm/wasm.h
@@ -226,6 +226,8 @@ class WasmBase : public std::enable_shared_from_this<WasmBase> {
   WasmCallVoid<0> _start_;      /* WASI command (Emscripten v1.39.0+, TinyGo) */
 
   WasmCallWord<2> main_;
+  WasmCallWord<0> __main_void_;
+
   WasmCallWord<1> malloc_;
 
   // Calls into the VM.
diff --git a/include/proxy-wasm/wasm_vm.h b/include/proxy-wasm/wasm_vm.h
index e2e2ea0bb..9fc435d35 100644
--- a/include/proxy-wasm/wasm_vm.h
+++ b/include/proxy-wasm/wasm_vm.h
@@ -71,8 +71,8 @@ using WasmCallWord = std::function<WasmCallInFuncType<N, Word, ContextBase *, Wo
 #define FOR_ALL_WASM_VM_EXPORTS(_f)                                                                \
   _f(proxy_wasm::WasmCallVoid<0>) _f(proxy_wasm::WasmCallVoid<1>) _f(proxy_wasm::WasmCallVoid<2>)  \
       _f(proxy_wasm::WasmCallVoid<3>) _f(proxy_wasm::WasmCallVoid<5>)                              \
-          _f(proxy_wasm::WasmCallWord<1>) _f(proxy_wasm::WasmCallWord<2>)                          \
-              _f(proxy_wasm::WasmCallWord<3>)
+          _f(proxy_wasm::WasmCallWord<0>) _f(proxy_wasm::WasmCallWord<1>)                          \
+              _f(proxy_wasm::WasmCallWord<2>) _f(proxy_wasm::WasmCallWord<3>)
 
 // These are templates and its helper for constructing signatures of functions callbacks from Wasm
 // VMs.
diff --git a/src/wasm.cc b/src/wasm.cc
index a1b4c1836..6502cd03f 100644
--- a/src/wasm.cc
+++ b/src/wasm.cc
@@ -162,6 +162,7 @@ void WasmBase::getFunctions() {
   _GET(_initialize);
   if (_initialize_) {
     _GET(main);
+    _GET(__main_void);
   } else {
     _GET(_start);
   }
@@ -410,6 +411,8 @@ void WasmBase::startVm(ContextBase *root_context) {
       // Re-using main() keeps this consistent when switching between
       // WASI command (that calls main()) and reactor (that doesn't).
       main_(root_context, Word(0), Word(0));
+    } else if (__main_void_) {
+      __main_void_(root_context);
     }
   } else if (_start_) {
     // WASI command.