Avoid unconditionally exporting stack functions (#21075)

See #11898

Author: sbc100

ChangeLog.md

@@ -20,6 +20,10 @@ See docs/process.md for more on how version tagging works.
 
 3.1.52 (in development)
 -----------------------
+- The core stack manipulation functions (`stackSave`, `stackRestore`,
+  `stackAlloc`) are no longer exported by default.  Users of these function
+  now need to depend on them explictly (either via `__deps` attributes or via
+  `-sEXPORTED_FUNCTIONS`). (#21075)
 - Building with `pthreads+EXPORT_ES6` will now emit the worker file as
   `NAME.worker.mjs` rather than `.js`. This is a necessary breaking change to
   resolve other `pthreads+EXPORT_ES6` issues in Node.js (because Node.js is

src/library.js

@@ -594,6 +594,7 @@ addToLibrary({
 #endif
 
   $withStackSave__internal: true,
+  $withStackSave__deps: ['stackSave', 'stackRestore'],
   $withStackSave: (f) => {
     var stack = stackSave();
     var ret = f();

src/library_async.js

@@ -538,7 +538,7 @@ addToLibrary({
     });
   },
 
-  $Fibers__deps: ['$Asyncify', 'emscripten_stack_set_limits'],
+  $Fibers__deps: ['$Asyncify', 'emscripten_stack_set_limits', 'stackRestore'],
   $Fibers: {
     nextFiber: 0,
     trampolineRunning: false,
@@ -598,7 +598,7 @@ addToLibrary({
     },
   },
 
-  emscripten_fiber_swap__deps: ["$Asyncify", "$Fibers"],
+  emscripten_fiber_swap__deps: ["$Asyncify", "$Fibers", 'stackSave'],
   emscripten_fiber_swap__async: true,
   emscripten_fiber_swap: (oldFiber, newFiber) => {
     if (ABORT) return;

src/library_ccall.js

@@ -15,7 +15,7 @@ addToLibrary({
   },
 
   // C calling interface.
-  $ccall__deps: ['$getCFunc', '$writeArrayToMemory', '$stringToUTF8OnStack'],
+  $ccall__deps: ['$getCFunc', '$writeArrayToMemory', '$stringToUTF8OnStack', 'stackSave', 'stackRestore', 'stackAlloc'],
   $ccall__docs: `
   /**
    * @param {string|null=} returnType

src/library_dylink.js

@@ -72,7 +72,7 @@ var LibraryDylink = {
   // generation time.
 #if !DISABLE_EXCEPTION_CATCHING || SUPPORT_LONGJMP == 'emscripten'
   $createInvokeFunction__internal: true,
-  $createInvokeFunction__deps: ['$dynCall', 'setThrew'],
+  $createInvokeFunction__deps: ['$dynCall', 'setThrew', 'stackSave', 'stackRestore'],
   $createInvokeFunction: (sig) => {
     return function() {
       var sp = stackSave();

src/library_exceptions.js

@@ -287,7 +287,7 @@ var LibraryExceptions = {
 
 #endif
 #if WASM_EXCEPTIONS || !DISABLE_EXCEPTION_CATCHING
-  $getExceptionMessageCommon__deps: ['__get_exception_message', 'free', '$withStackSave'],
+  $getExceptionMessageCommon__deps: ['__get_exception_message', 'free', '$withStackSave', 'stackAlloc'],
   $getExceptionMessageCommon: (ptr) => withStackSave(() => {
     var type_addr_addr = stackAlloc({{{ POINTER_SIZE }}});
     var message_addr_addr = stackAlloc({{{ POINTER_SIZE }}});

src/library_legacy.js

@@ -17,7 +17,7 @@ addToLibrary({
    * @param {(Uint8Array|Array<number>)} slab: An array of data.
    * @param {number=} allocator : How to allocate memory, see ALLOC_*
    */
-  $allocate__deps: ['$ALLOC_NORMAL', '$ALLOC_STACK', 'malloc'],
+  $allocate__deps: ['$ALLOC_NORMAL', '$ALLOC_STACK', 'malloc', 'stackAlloc'],
   $allocate: (slab, allocator) => {
     var ret;
   #if ASSERTIONS

src/library_promise.js

@@ -76,7 +76,10 @@ addToLibrary({
 
   $makePromiseCallback__deps: ['$getPromise',
                                '$POINTER_SIZE',
-                               'emscripten_promise_destroy'],
+                               'emscripten_promise_destroy',
+                               'stackAlloc',
+                               'stackRestore',
+                               'stackSave'],
   $makePromiseCallback: (callback, userData) => {
     return (value) => {
 #if RUNTIME_DEBUG

src/library_pthread.js

@@ -1063,6 +1063,7 @@ var LibraryPThread = {
   },
 
   $establishStackSpace__internal: true,
+  $establishStackSpace__deps: ['stackRestore'],
   $establishStackSpace: () => {
     var pthread_ptr = _pthread_self();
     var stackHigh = {{{ makeGetValue('pthread_ptr', C_STRUCTS.pthread.stack, '*') }}};

src/library_sdl.js

@@ -2144,7 +2144,7 @@ var LibrarySDL = {
   // We support JPG, PNG, TIF because browsers do
   IMG_Init: (flags) => flags,
 
-  IMG_Load_RW__deps: ['SDL_LockSurface', 'SDL_FreeRW', '$PATH_FS', '$withStackSave', '$stringToUTF8OnStack'],
+  IMG_Load_RW__deps: ['SDL_LockSurface', 'SDL_FreeRW', '$PATH_FS', '$withStackSave', '$stringToUTF8OnStack', 'stackAlloc'],
   IMG_Load_RW__proxy: 'sync',
   IMG_Load_RW: (rwopsID, freeSrc) => {
     try {

src/library_webgl.js

@@ -4003,7 +4003,7 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
   glMultiDrawElements: 'glMultiDrawElementsWEBGL',
   glMultiDrawElementsANGLE: 'glMultiDrawElementsWEBGL',
 #if MEMORY64
-  glMultiDrawElementsWEBGL__deps: ['$convertOffsets'],
+  glMultiDrawElementsWEBGL__deps: ['$convertOffsets', 'stackSave', 'stackRestore'],
 #endif
   glMultiDrawElementsWEBGL: (mode, counts, type, offsets, drawcount) => {
 #if MEMORY64
@@ -4026,7 +4026,7 @@ for (/**@suppress{duplicate}*/var i = 0; i < {{{ GL_POOL_TEMP_BUFFERS_SIZE }}};
   glMultiDrawElementsInstancedWEBGL__sig: 'vipippi',
   glMultiDrawElementsInstancedANGLE: 'glMultiDrawElementsInstancedWEBGL',
 #if MEMORY64
-  glMultiDrawElementsInstancedWEBGL__deps: ['$convertOffsets'],
+  glMultiDrawElementsInstancedWEBGL__deps: ['$convertOffsets', 'stackSave', 'stackRestore'],
 #endif
   glMultiDrawElementsInstancedWEBGL: (mode, counts, type, offsets, instanceCounts, drawcount) => {
 #if MEMORY64

test/other/metadce/test_metadce_cxx_except_wasm.exports

@@ -9,5 +9,3 @@ dynCall_viijii
 main
 memory
 stackAlloc
-stackRestore
-stackSave

test/other/metadce/test_metadce_cxx_except_wasm.size

@@ -1 +1 @@
-139264
+139221

tools/link.py

@@ -1279,7 +1279,13 @@ def phase_linker_setup(options, state, newargs):
     if sym in settings.EXPORTED_RUNTIME_METHODS:
       settings.REQUIRED_EXPORTS.append(sym)
 
-  settings.REQUIRED_EXPORTS += ['stackSave', 'stackRestore', 'stackAlloc']
+  if settings.MAIN_READS_PARAMS and not settings.STANDALONE_WASM:
+    # callMain depends on stackAlloc
+    settings.REQUIRED_EXPORTS += ['stackAlloc']
+
+  if settings.SUPPORT_LONGJMP == 'emscripten' or not settings.DISABLE_EXCEPTION_CATCHING:
+    # make_invoke depends on stackSave and stackRestore
+    settings.REQUIRED_EXPORTS += ['stackSave', 'stackRestore']
 
   if settings.RELOCATABLE:
     # TODO(https://reviews.llvm.org/D128515): Make this mandatory once