EMSCRIPTEN_KEEPALIVE

2 files changed, 16 insertions, 1 deletions

diff --git a/system/include/emscripten.h b/system/include/emscripten.h
index 70524835..e265e8fd 100644
--- a/system/include/emscripten.h
+++ b/system/include/emscripten.h
@@ -12,6 +12,16 @@ extern "C" {
 #endif
 
 /*
+ * Forces LLVM to not dead-code-eliminate a function. Note that
+ * closure may still eliminate it at the JS level, for which you
+ * should use EXPORTED_FUNCTIONS (see settings.js).
+ *
+ * Example usage:
+ *   void EMSCRIPTEN_KEEPALIVE my_function() { .. }
+ */
+#define EMSCRIPTEN_KEEPALIVE __attribute__((used))
+
+/*
  * Interface to the underlying JS engine. This function will
  * eval() the given script.
  */
diff --git a/tests/runner.py b/tests/runner.py
index 77b648ec..c3f8cff7 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -2449,10 +2449,15 @@ m_divisor is 1091269979
           #include <stdio.h>
           #include "emscripten.h"
 
+          extern "C" {
+            void EMSCRIPTEN_KEEPALIVE save_me_aimee() { printf("mann\n"); }
+          }
+
           int main() {
             // EMSCRIPTEN_COMMENT("hello from the source");
             emscripten_run_script("Module.print('hello world' + '!')");
             printf("*%d*\n", emscripten_run_script_int("5*20"));
+            emscripten_run_script("_save_me_aimee()");
             return 0;
           }
           '''
@@ -2463,7 +2468,7 @@ def process(filename):
   # TODO: restore this (see comment in emscripten.h) assert '// hello from the source' in src
 '''
 
-        self.do_run(src, 'hello world!\n*100*', post_build=check)
+        self.do_run(src, 'hello world!\n*100*\nmann\n', post_build=check)
 
     def test_inlinejs(self):
         src = r'''