Add addAtPreRun function for code injection at preRun.

src/jsifier.mjs

@@ -9,6 +9,7 @@
 
 import {
   ATEXITS,
+  ATPRERUN,
   ATINITS,
   ATMAINS,
   defineI64Param,
@@ -773,6 +774,7 @@ var proxiedFunctionTable = [
           warnings: warningOccured(),
           asyncFuncs,
           libraryDefinitions: LibraryManager.libraryDefinitions,
+          ATPRERUN: ATPRERUN.join('\n'),
           ATINITS: ATINITS.join('\n'),
           ATMAINS: STRICT ? '' : ATMAINS.join('\n'),
           ATEXITS: ATEXITS.join('\n'),

src/lib/libfs.js

@@ -33,7 +33,7 @@ addToLibrary({
   ],
   $FS__postset: () => {
     // TODO: do we need noFSInit?
-    addAtInit(`
+    addAtPreRun(`
 if (!Module['noFSInit'] && !FS.initialized)
   FS.init();
 FS.ignorePermissions = false;

src/parseTools.mjs

@@ -733,6 +733,14 @@ function makeEval(code) {
 
 export const ATMAINS = [];
 
+export const ATPRERUN = [];
+
+// Add code that runs after the Wasm module is loaded and the runtime ATINIT
+// callbacks, but before static constructors and main are run.
+function addAtPreRun(code) {
+  ATPRERUN.push(code);
+}
+
 export const ATINITS = [];
 
 function addAtInit(code) {
@@ -1085,6 +1093,7 @@ function ENVIRONMENT_IS_WORKER_THREAD() {
 
 addToCompileTimeContext({
   ATEXITS,
+  ATPRERUN,
   ATINITS,
   FOUR_GB,
   LONG_TYPE,
@@ -1104,6 +1113,7 @@ addToCompileTimeContext({
   ENVIRONMENT_IS_WORKER_THREAD,
   addAtExit,
   addAtInit,
+  addAtPreRun,
   asyncIf,
   awaitIf,
   buildStringArray,

src/postamble_minimal.js

@@ -217,7 +217,7 @@ WebAssembly.instantiate(Module['wasm'], imports).then((output) => {
 #endif
   updateMemoryViews();
 #endif
-
+  <<< ATPRERUN >>>
   initRuntime(wasmExports);
 #if PTHREADS
   // Export Wasm module for pthread creation to access.

src/preamble.js

@@ -187,6 +187,7 @@ function preRun() {
   }
 #endif
   callRuntimeCallbacks(__ATPRERUN__);
+  <<< ATPRERUN >>>
 }
 
 function initRuntime() {
@@ -217,6 +218,11 @@ function initRuntime() {
 #if RELOCATABLE
   callRuntimeCallbacks(__RELOC_FUNCS__);
 #endif
+
+#if hasExportedSymbol('__wasm_call_ctors')
+  wasmExports['__wasm_call_ctors']();
+#endif
+
   <<< ATINITS >>>
   callRuntimeCallbacks(__ATINIT__);
 }
@@ -954,10 +960,6 @@ function getWasmImports() {
 #endif
 #endif
 
-#if hasExportedSymbol('__wasm_call_ctors')
-    addOnInit(wasmExports['__wasm_call_ctors']);
-#endif
-
 #if hasExportedSymbol('__wasm_apply_data_relocs')
     __RELOC_FUNCS__.push(wasmExports['__wasm_apply_data_relocs']);
 #endif

test/test_other.py

@@ -8431,6 +8431,30 @@ def test_binaryen_stack_ir(self, opts, disable_and_enable):
     self.assertLess(err.count(DISABLE), 2)
     self.assertLess(err.count(ENABLE), 2)
 
+  @also_with_minimal_runtime
+  def test_run_order(self):
+    create_file('lib.js', r'''
+addToLibrary({
+  foo__postset: () => {
+    addAtPreRun("console.log(`addAtPreRun`);");
+    addAtInit("console.log(`addAtInit`);");
+  },
+  foo: () => {},
+});
+''')
+    create_file('src.c', r'''
+    #include <stdio.h>
+    void foo();
+    __attribute__((constructor)) void ctor() {
+      printf("ctor\n");
+    }
+    int main() {
+      printf("main\n");
+      foo();
+    }
+    ''')
+    self.do_runf('src.c', 'addAtPreRun\nctor\naddAtInit\nmain\n', emcc_args=['--js-library', 'lib.js'])
+
   def test_override_js_execution_environment(self):
     create_file('main.c', r'''
       #include <emscripten.h>

tools/building.py

@@ -393,10 +393,7 @@ def acorn_optimizer(filename, passes, extra_info=None, return_output=False, work
 # evals ctors. if binaryen_bin is provided, it is the dir of the binaryen tool
 # for this, and we are in wasm mode
 def eval_ctors(js_file, wasm_file, debug_info):
-  if settings.MINIMAL_RUNTIME:
-    CTOR_ADD_PATTERN = f"wasmExports['{WASM_CALL_CTORS}']();" # TODO test
-  else:
-    CTOR_ADD_PATTERN = f"addOnInit(wasmExports['{WASM_CALL_CTORS}']);"
+  CTOR_ADD_PATTERN = f"wasmExports['{WASM_CALL_CTORS}']();"
 
   js = utils.read_file(js_file)
 

tools/emscripten.py

@@ -161,6 +161,7 @@ def update_settings_glue(wasm_file, metadata, base_metadata):
 
 
 def apply_static_code_hooks(forwarded_json, code):
+  code = shared.do_replace(code, '<<< ATPRERUN >>>', str(forwarded_json['ATPRERUN']))
   code = shared.do_replace(code, '<<< ATINITS >>>', str(forwarded_json['ATINITS']))
   if settings.HAS_MAIN:
     code = shared.do_replace(code, '<<< ATMAINS >>>', str(forwarded_json['ATMAINS']))