Make wasmTable into a library symbol (#20158)

Author: sbc100

ChangeLog.md

@@ -20,6 +20,10 @@ See docs/process.md for more on how version tagging works.
 
 3.1.46 (in development)
 -----------------------
+- The `wasmTable` global is now a JS library function that will only be included
+  as needed.  Code that references `wasmTable` will no need to declare a
+  dependency on it.  It can also be explictly included using
+  `-sEXPORTED_RUNTIME_METHODS=wasmTable`.
 - libunwind updated to LLVM 16.0.6. (#20088)
 - The `--minify=0` commnad line flag will now preserve comments as well as
   whitespace.  This means the resulting output can then be run though closure

emcc.py

@@ -2121,6 +2121,9 @@ def phase_linker_setup(options, state, newargs):
   if not settings.BOOTSTRAPPING_STRUCT_INFO and settings.SAFE_HEAP:
     settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$getValue_safe', '$setValue_safe']
 
+  if settings.ABORT_ON_WASM_EXCEPTIONS or settings.SPLIT_MODULE:
+    settings.DEFAULT_LIBRARY_FUNCS_TO_INCLUDE += ['$wasmTable']
+
   if settings.MAIN_MODULE:
     assert not settings.SIDE_MODULE
     if settings.MAIN_MODULE == 1:

src/jsifier.js

@@ -509,6 +509,8 @@ function(${args}) {
         //   'var foo;[code here verbatim];'
         contentText = 'var ' + mangled + snippet;
         if (snippet[snippet.length - 1] != ';' && snippet[snippet.length - 1] != '}') contentText += ';';
+      } else if (typeof snippet == 'undefined') {
+        contentText = `var ${mangled};`;
       } else {
         // In JS libraries
         //   foo: '=[value]'

src/library.js

@@ -3199,7 +3199,7 @@ addToLibrary({
   $wasmTableMirror: [],
 
   $setWasmTableEntry__internal: true,
-  $setWasmTableEntry__deps: ['$wasmTableMirror'],
+  $setWasmTableEntry__deps: ['$wasmTableMirror', '$wasmTable'],
   $setWasmTableEntry: (idx, func) => {
     wasmTable.set(idx, func);
     // With ABORT_ON_WASM_EXCEPTIONS wasmTable.get is overriden to return wrapped
@@ -3209,7 +3209,7 @@ addToLibrary({
   },
 
   $getWasmTableEntry__internal: true,
-  $getWasmTableEntry__deps: ['$wasmTableMirror'],
+  $getWasmTableEntry__deps: ['$wasmTableMirror', '$wasmTable'],
   $getWasmTableEntry: (funcPtr) => {
 #if MEMORY64
     // Function pointers are 64-bit, but wasmTable.get() requires a Number.
@@ -3234,8 +3234,10 @@ addToLibrary({
 
 #else
 
+  $setWasmTableEntry__deps: ['$wasmTable'],
   $setWasmTableEntry: (idx, func) => wasmTable.set(idx, func),
 
+  $getWasmTableEntry__deps: ['$wasmTable'],
   $getWasmTableEntry: (funcPtr) => {
 #if MEMORY64
     // Function pointers are 64-bit, but wasmTable.get() requires a Number.
@@ -3612,6 +3614,20 @@ addToLibrary({
   $getNativeTypeSize__deps: ['$POINTER_SIZE'],
   $getNativeTypeSize: {{{ getNativeTypeSize }}},
 
+#if RELOCATABLE
+  // In RELOCATABLE mode we create the table in JS.
+  $wasmTable: `=new WebAssembly.Table({
+  'initial': {{{ INITIAL_TABLE }}},
+#if !ALLOW_TABLE_GROWTH
+  'maximum': {{{ INITIAL_TABLE }}},
+#endif
+  'element': 'anyfunc'
+});
+`,
+#else
+  $wasmTable: undefined,
+#endif
+
   // We used to define these globals unconditionally in support code.
   // Instead, we now define them here so folks can pull it in explicitly, on
   // demand.

src/library_addfunction.js

@@ -141,7 +141,7 @@ addToLibrary({
   // Weak map of functions in the table to their indexes, created on first use.
   $functionsInTableMap: undefined,
 
-  $getEmptyTableSlot__deps: ['$freeTableIndexes'],
+  $getEmptyTableSlot__deps: ['$freeTableIndexes', '$wasmTable'],
   $getEmptyTableSlot: () => {
     // Reuse a free index if there is one, otherwise grow.
     if (freeTableIndexes.length) {
@@ -172,7 +172,7 @@ addToLibrary({
     }
   },
 
-  $getFunctionAddress__deps: ['$updateTableMap', '$functionsInTableMap'],
+  $getFunctionAddress__deps: ['$updateTableMap', '$functionsInTableMap', '$wasmTable'],
   $getFunctionAddress: (func) => {
     // First, create the map if this is the first use.
     if (!functionsInTableMap) {
@@ -189,7 +189,8 @@ addToLibrary({
   $addFunction__docs: '/** @param {string=} sig */',
   $addFunction__deps: ['$convertJsFunctionToWasm', '$getFunctionAddress',
                        '$functionsInTableMap', '$getEmptyTableSlot',
-                       '$getWasmTableEntry', '$setWasmTableEntry'],
+                       '$getWasmTableEntry', '$setWasmTableEntry',
+                       '$wasmTable'],
   $addFunction: (func, sig) => {
   #if ASSERTIONS
     assert(typeof func != 'undefined');

src/library_dylink.js

@@ -581,6 +581,7 @@ var LibraryDylink = {
   },
 
 #if DYLINK_DEBUG
+  $dumpTable__deps: ['$wasmTable'],
   $dumpTable: () => {
     for (var i = 0; i < wasmTable.length; i++)
       dbg(`table: ${i} : ${wasmTable.get(i)}`);
@@ -601,6 +602,7 @@ var LibraryDylink = {
     '$getDylinkMetadata', '$alignMemory', '$zeroMemory',
     '$currentModuleWeakSymbols',
     '$updateTableMap',
+    '$wasmTable',
   ],
   $loadWebAssemblyModule: (binary, flags, libName, localScope, handle) => {
 #if DYLINK_DEBUG

src/library_makeDynCall.js

@@ -5,7 +5,7 @@
  */
 
 addToLibrary({
-  $createDyncallWrapper__deps: ['$generateFuncType', '$uleb128Encode', 'setTempRet0'],
+  $createDyncallWrapper__deps: ['$generateFuncType', '$uleb128Encode', 'setTempRet0', '$wasmTable'],
   $createDyncallWrapper: (sig) => {
     var sections = [];
     var prelude = [

src/modules.js

@@ -381,7 +381,6 @@ function exportRuntime() {
     'abort',
     'keepRuntimeAlive',
     'wasmMemory',
-    'wasmTable',
     'wasmExports',
   ];
 

src/postamble_minimal.js

@@ -187,10 +187,12 @@ WebAssembly.instantiate(Module['wasm'], imports).then((output) => {
 #else
   <<< WASM_MODULE_EXPORTS >>>
 #endif
+#if '$wasmTable' in addedLibraryItems
   wasmTable = wasmExports['__indirect_function_table'];
 #if ASSERTIONS
   assert(wasmTable);
 #endif
+#endif
 
 #if AUDIO_WORKLET
   // If we are in the audio worklet environment, we can only access the Module object

src/preamble.js

@@ -175,7 +175,6 @@ assert(!Module['wasmMemory'], 'Use of `wasmMemory` detected.  Use -sIMPORTED_MEM
 assert(!Module['INITIAL_MEMORY'], 'Detected runtime INITIAL_MEMORY setting.  Use -sIMPORTED_MEMORY to define wasmMemory dynamically');
 #endif // !IMPORTED_MEMORY && ASSERTIONS
 
-#include "runtime_init_table.js"
 #include "runtime_stack_check.js"
 #include "runtime_assertions.js"
 
@@ -1010,20 +1009,20 @@ function createWasm() {
     runMemoryInitializer();
 #endif
 
-#if !RELOCATABLE
+#if '$wasmTable' in addedLibraryItems && !RELOCATABLE
     wasmTable = wasmExports['__indirect_function_table'];
     {{{ receivedSymbol('wasmTable') }}}
 #if ASSERTIONS && !PURE_WASI
     assert(wasmTable, "table not found in wasm exports");
 #endif
-#endif
 
 #if AUDIO_WORKLET
     // If we are in the audio worklet environment, we can only access the Module object
     // and not the global scope of the main JS script. Therefore we need to export
     // all functions that the audio worklet scope needs onto the Module object.
     Module['wasmTable'] = wasmTable;
 #endif
+#endif
 
 #if hasExportedSymbol('__wasm_call_ctors')
     addOnInit(wasmExports['__wasm_call_ctors']);