Use standard named for native manipulation functions. NFC (#21555)

We continue to use the JS names when calling from JS code but use
prefixed, native symbol names for the native implementation.

I'm hoping we can eventually completely remove the `WASM_SYSTEM_EXPORTS`
special casing.

Author: sbc100

ChangeLog.md

@@ -22,12 +22,22 @@ See docs/process.md for more on how version tagging works.
 -----------------------
 - In `MODULARIZE` mode we no longer export the module ready promise as `ready`.
   This was previously exposed on the Module for historical reasons even though
-  in `MODULARIZE` mode the only way to get access to the module is to wait on the
-  promise returned from the factory function. (#21564)
+  in `MODULARIZE` mode the only way to get access to the module is to wait on
+  the promise returned from the factory function. (#21564)
 - JS library code is now executed in its own context/scope, which limits how
   much of the compiler internals are accessible. If there are build time JS
   symbols that you are depending on, but that were not added to this scope,
   please file a bug and we can add more to this scope. (#21542)
+- The JS functions for manipulating the native/shadow stack
+  (`stackSave`/`stackRestore`/`stackAlloc`) are now just regular JS library
+  function and as such are only included if you explicitly depend on them.  If
+  you use these functions in your JS code you will need to depend on them via
+  either:
+  - The `EM_JS_DEPS` macro for `EM_ASM`/`EM_JS` code.
+  - The `__deps` attribute for JS library functions
+  - The `-sDEFAULT_LIBRARY_FUNCS_TO_INCLUDE` flag for `--pre-js`/`--post-js`
+    code
+  (#21555)
 
 3.1.56 - 03/14/24
 -----------------

src/jsifier.mjs

@@ -31,6 +31,7 @@ import {
   printErr,
   read,
   warn,
+  warnOnce,
   warningOccured,
 } from './utility.mjs';
 import {LibraryManager, librarySymbols} from './modules.mjs';

src/library.js

@@ -21,6 +21,20 @@
 // new function with an '_', it will not be found.
 
 addToLibrary({
+  // JS aliases for native stack manipulation functions
+  $stackSave__deps: ['emscripten_stack_get_current'],
+  $stackSave: () => _emscripten_stack_get_current(),
+  $stackRestore__deps: ['_emscripten_stack_restore'],
+  $stackRestore: (val) => __emscripten_stack_restore(val),
+  $stackAlloc__deps: ['_emscripten_stack_alloc'],
+  $stackAlloc: (sz) => __emscripten_stack_alloc(sz),
+
+  // Aliases that allow legacy names (without leading $) for these
+  // stack functions to continue to work in `__deps` entries.
+  stackAlloc: '$stackAlloc',
+  stackSave: '$stackSave',
+  stackRestore: '$stackSave',
+
   $ptrToString: (ptr) => {
 #if ASSERTIONS
     assert(typeof ptr === 'number');
@@ -596,7 +610,7 @@ addToLibrary({
 #endif
 
   $withStackSave__internal: true,
-  $withStackSave__deps: ['stackSave', 'stackRestore'],
+  $withStackSave__deps: ['$stackSave', '$stackRestore'],
   $withStackSave: (f) => {
     var stack = stackSave();
     var ret = f();

src/library_async.js

@@ -541,7 +541,7 @@ addToLibrary({
     });
   },
 
-  $Fibers__deps: ['$Asyncify', 'emscripten_stack_set_limits', 'stackRestore'],
+  $Fibers__deps: ['$Asyncify', 'emscripten_stack_set_limits', '$stackRestore'],
   $Fibers: {
     nextFiber: 0,
     trampolineRunning: false,
@@ -601,7 +601,7 @@ addToLibrary({
     },
   },
 
-  emscripten_fiber_swap__deps: ["$Asyncify", "$Fibers", 'stackSave'],
+  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', 'stackSave', 'stackRestore', 'stackAlloc'],
+  $ccall__deps: ['$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', 'stackSave', 'stackRestore'],
+  $createInvokeFunction__deps: ['$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', 'stackAlloc'],
+  $getExceptionMessageCommon__deps: ['__get_exception_message', 'free', '$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 @@ legacyFuncs = {
    * @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', 'stackAlloc'],
+  $allocate__deps: ['$ALLOC_NORMAL', '$ALLOC_STACK', 'malloc', '$stackAlloc'],
   $allocate: (slab, allocator) => {
     var ret;
   #if ASSERTIONS

src/library_promise.js

@@ -77,9 +77,9 @@ addToLibrary({
   $makePromiseCallback__deps: ['$getPromise',
                                '$POINTER_SIZE',
                                'emscripten_promise_destroy',
-                               'stackAlloc',
-                               'stackRestore',
-                               'stackSave'],
+                               '$stackAlloc',
+                               '$stackRestore',
+                               '$stackSave'],
   $makePromiseCallback: (callback, userData) => {
     return (value) => {
 #if RUNTIME_DEBUG

src/library_pthread.js

@@ -960,7 +960,7 @@ var LibraryPThread = {
   $proxyToMainThreadPtr: (...args) => BigInt(proxyToMainThread(...args)),
 #endif
 
-  $proxyToMainThread__deps: ['$withStackSave', '_emscripten_run_on_main_thread_js'].concat(i53ConversionDeps),
+  $proxyToMainThread__deps: ['$withStackSave', '$stackAlloc', '_emscripten_run_on_main_thread_js'].concat(i53ConversionDeps),
   $proxyToMainThread__docs: '/** @type{function(number, (number|boolean), ...number)} */',
   $proxyToMainThread: (funcIndex, emAsmAddr, sync, ...callArgs) => {
     // EM_ASM proxying is done by passing a pointer to the address of the EM_ASM
@@ -1065,7 +1065,7 @@ var LibraryPThread = {
   },
 
   $establishStackSpace__internal: true,
-  $establishStackSpace__deps: ['stackRestore'],
+  $establishStackSpace__deps: ['$stackRestore'],
   $establishStackSpace: () => {
     var pthread_ptr = _pthread_self();
     var stackHigh = {{{ makeGetValue('pthread_ptr', C_STRUCTS.pthread.stack, '*') }}};