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library_dylink.js
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library_dylink.js
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/**
* @license
* Copyright 2020 The Emscripten Authors
* SPDX-License-Identifier: MIT
*
* Dynamic library loading
*/
var dlopenMissingError = "'To use dlopen, you need enable dynamic linking, see https://emscripten.org/docs/compiling/Dynamic-Linking.html'"
var LibraryDylink = {
#if RELOCATABLE
#if FILESYSTEM
$registerWasmPlugin__deps: ['$preloadPlugins'],
$registerWasmPlugin: function() {
// Use string keys here to avoid minification since the plugin consumer
// also uses string keys.
var wasmPlugin = {
'promiseChainEnd': Promise.resolve(),
'canHandle': function(name) {
return !Module.noWasmDecoding && name.endsWith('.so')
},
'handle': function(byteArray, name, onload, onerror) {
// loadWebAssemblyModule can not load modules out-of-order, so rather
// than just running the promises in parallel, this makes a chain of
// promises to run in series.
wasmPlugin['promiseChainEnd'] = wasmPlugin['promiseChainEnd'].then(
() => loadWebAssemblyModule(byteArray, {loadAsync: true, nodelete: true}, name)).then(
(exports) => {
#if DYLINK_DEBUG
dbg(`registering preloadedWasm: ${name}`);
#endif
preloadedWasm[name] = exports;
onload(byteArray);
},
(error) => {
err(`failed to instantiate wasm: ${name}: ${error}`);
onerror();
});
}
};
preloadPlugins.push(wasmPlugin);
},
$preloadedWasm__deps: ['$registerWasmPlugin'],
$preloadedWasm__postset: `
registerWasmPlugin();
`,
$preloadedWasm: {},
#endif // FILESYSTEM
$isSymbolDefined: function(symName) {
// Ignore 'stub' symbols that are auto-generated as part of the original
// `wasmImports` used to instantate the main module.
var existing = wasmImports[symName];
if (!existing || existing.stub) {
return false;
}
#if ASYNCIFY
// Even if a symbol exists in wasmImports, and is not itself a stub, it
// could be an ASYNCIFY wrapper function that wraps a stub function.
if (symName in asyncifyStubs && !asyncifyStubs[symName]) {
return false;
}
#endif
return true;
},
// Dynamic version of shared.py:make_invoke. This is needed for invokes
// that originate from side modules since these are not known at JS
// generation time.
#if !DISABLE_EXCEPTION_CATCHING || SUPPORT_LONGJMP == 'emscripten'
$createInvokeFunction__internal: true,
$createInvokeFunction__deps: ['$dynCall', 'setThrew'],
$createInvokeFunction: function(sig) {
return function() {
var sp = stackSave();
try {
return dynCall(sig, arguments[0], Array.prototype.slice.call(arguments, 1));
} catch(e) {
stackRestore(sp);
// Create a try-catch guard that rethrows the Emscripten EH exception.
#if EXCEPTION_STACK_TRACES
// Exceptions thrown from C++ and longjmps will be an instance of
// EmscriptenEH.
if (!(e instanceof EmscriptenEH)) throw e;
#else
// Exceptions thrown from C++ will be a pointer (number) and longjmp
// will throw the number Infinity. Use the compact and fast "e !== e+0"
// test to check if e was not a Number.
if (e !== e+0) throw e;
#endif
_setThrew(1, 0);
}
}
},
#endif
// Resolve a global symbol by name. This is used during module loading to
// resolve imports, and by `dlsym` when used with `RTLD_DEFAULT`.
// Returns both the resolved symbol (i.e. a function or a global) along with
// the canonical name of the symbol (in some cases is modify the symbol as
// part of the loop process, so that actual symbol looked up has a different
// name).
$resolveGlobalSymbol__deps: ['$isSymbolDefined',
#if !DISABLE_EXCEPTION_CATCHING || SUPPORT_LONGJMP == 'emscripten'
'$createInvokeFunction',
#endif
],
$resolveGlobalSymbol__internal: true,
$resolveGlobalSymbol: function(symName, direct = false) {
var sym;
#if !WASM_BIGINT
// First look for the orig$ symbol which is the symbol without i64
// legalization performed.
if (direct && ('orig$' + symName in wasmImports)) {
symName = 'orig$' + symName;
}
#endif
#if !DISABLE_EXCEPTION_CATCHING
if (symName.startsWith('__cxa_find_matching_catch_')) {
symName = '__cxa_find_matching_catch';
}
#endif
if (isSymbolDefined(symName)) {
sym = wasmImports[symName];
}
#if !DISABLE_EXCEPTION_CATCHING || SUPPORT_LONGJMP == 'emscripten'
// Asm.js-style exception handling: invoke wrapper generation
else if (symName.startsWith('invoke_')) {
// Create (and cache) new invoke_ functions on demand.
sym = wasmImports[symName] = createInvokeFunction(symName.split('_')[1]);
}
#endif
return {sym: sym, name: symName};
},
$GOT: {},
$currentModuleWeakSymbols: '=new Set({{{ JSON.stringify(Array.from(WEAK_IMPORTS)) }}})',
// Create globals to each imported symbol. These are all initialized to zero
// and get assigned later in `updateGOT`
$GOTHandler__internal: true,
$GOTHandler__deps: ['$GOT', '$currentModuleWeakSymbols'],
$GOTHandler: {
'get': function(obj, symName) {
var rtn = GOT[symName];
if (!rtn) {
rtn = GOT[symName] = new WebAssembly.Global({'value': '{{{ POINTER_WASM_TYPE }}}', 'mutable': true});
#if DYLINK_DEBUG == 2
dbg("new GOT entry: " + symName);
#endif
}
if (!currentModuleWeakSymbols.has(symName)) {
// Any non-weak reference to a symbol marks it as `required`, which
// enabled `reportUndefinedSymbols` to report undefeind symbol errors
// correctly.
rtn.required = true;
}
return rtn;
}
},
$isInternalSym__internal: true,
$isInternalSym: function(symName) {
// TODO: find a way to mark these in the binary or avoid exporting them.
return [
'__cpp_exception',
'__c_longjmp',
'__wasm_apply_data_relocs',
'__dso_handle',
'__tls_size',
'__tls_align',
'__set_stack_limits',
'_emscripten_tls_init',
'__wasm_init_tls',
'__wasm_call_ctors',
'__start_em_asm',
'__stop_em_asm',
].includes(symName)
#if SPLIT_MODULE
// Exports synthesized by wasm-split should be prefixed with '%'
|| symName[0] == '%'
#endif
;
},
$updateGOT__internal: true,
$updateGOT__deps: ['$GOT', '$isInternalSym', '$addFunction', '$getFunctionAddress'],
$updateGOT: function(exports, replace) {
#if DYLINK_DEBUG
dbg("updateGOT: adding " + Object.keys(exports).length + " symbols");
#endif
for (var symName in exports) {
if (isInternalSym(symName)) {
continue;
}
var value = exports[symName];
#if !WASM_BIGINT
if (symName.startsWith('orig$')) {
symName = symName.split('$')[1];
replace = true;
}
#endif
if (!GOT[symName]) {
GOT[symName] = new WebAssembly.Global({'value': '{{{ POINTER_WASM_TYPE }}}', 'mutable': true});
}
if (replace || GOT[symName].value == 0) {
#if DYLINK_DEBUG == 2
dbg(`updateGOT: before: ${symName} : ${GOT[symName].value}`);
#endif
if (typeof value == 'function') {
GOT[symName].value = {{{ to64('addFunction(value)') }}};
#if DYLINK_DEBUG == 2
dbg(`updateGOT: FUNC: ${symName} : ${GOT[symName].value}`);
#endif
} else if (typeof value == {{{ POINTER_JS_TYPE }}}) {
GOT[symName].value = value;
} else {
err(`unhandled export type for '${symName}': ${typeof value}`);
}
#if DYLINK_DEBUG == 2
dbg(`updateGOT: after: ${symName} : ${GOT[symName].value} (${value})`);
#endif
}
#if DYLINK_DEBUG
else if (GOT[symName].value != value) {
dbg(`udateGOT: EXISTING SYMBOL: ${symName} : ${GOT[symName].value} (${value})`);
}
#endif
}
#if DYLINK_DEBUG
dbg("done updateGOT");
#endif
},
// Applies relocations to exported things.
$relocateExports__internal: true,
$relocateExports__deps: ['$updateGOT'],
$relocateExports__docs: '/** @param {boolean=} replace */',
$relocateExports: function(exports, memoryBase, replace) {
var relocated = {};
for (var e in exports) {
var value = exports[e];
#if SPLIT_MODULE
// Do not modify exports synthesized by wasm-split
if (e.startsWith('%')) {
relocated[e] = value
continue;
}
#endif
if (typeof value == 'object') {
// a breaking change in the wasm spec, globals are now objects
// https://github.com/WebAssembly/mutable-global/issues/1
value = value.value;
}
if (typeof value == {{{ POINTER_JS_TYPE }}}) {
value += {{{ to64('memoryBase') }}};
}
relocated[e] = value;
}
updateGOT(relocated, replace);
return relocated;
},
$reportUndefinedSymbols__internal: true,
$reportUndefinedSymbols__deps: ['$GOT', '$resolveGlobalSymbol'],
$reportUndefinedSymbols: function() {
#if DYLINK_DEBUG
dbg('reportUndefinedSymbols');
#endif
for (var symName in GOT) {
if (GOT[symName].value == 0) {
var value = resolveGlobalSymbol(symName, true).sym;
if (!value && !GOT[symName].required) {
// Ignore undefined symbols that are imported as weak.
#if DYLINK_DEBUG
dbg(`ignoring undefined weak symbol: ${symName}`);
#endif
continue;
}
#if ASSERTIONS
assert(value, `undefined symbol '${symName}'. perhaps a side module was not linked in? if this global was expected to arrive from a system library, try to build the MAIN_MODULE with EMCC_FORCE_STDLIBS=1 in the environment`);
#endif
#if DYLINK_DEBUG == 2
dbg(`assigning dynamic symbol from main module: ${symName} -> ${prettyPrint(value)}`);
#endif
if (typeof value == 'function') {
/** @suppress {checkTypes} */
GOT[symName].value = {{{ to64('addFunction(value, value.sig)') }}};
#if DYLINK_DEBUG == 2
dbg(`assigning table entry for : ${symName} -> ${GOT[symName].value}`);
#endif
} else if (typeof value == 'number') {
GOT[symName].value = {{{ to64('value') }}};
#if MEMORY64
} else if (typeof value == 'bigint') {
GOT[symName].value = value;
#endif
} else {
throw new Error(`bad export type for '${symName}': ${typeof value}`);
}
}
}
#if DYLINK_DEBUG
dbg('done reportUndefinedSymbols');
#endif
},
#endif
#if !MAIN_MODULE
#if !ALLOW_UNIMPLEMENTED_SYSCALLS
_dlopen_js__deps: [function() { error(dlopenMissingError); }],
_emscripten_dlopen_js__deps: [function() { error(dlopenMissingError); }],
_dlsym_js__deps: [function() { error(dlopenMissingError); }],
_dlsym_catchup_js__deps: [function() { error(dlopenMissingError); }],
dlopen__deps: [function() { error(dlopenMissingError); }],
emscripten_dlopen__deps: [function() { error(dlopenMissingError); }],
__dlsym__deps: [function() { error(dlopenMissingError); }],
#else
$dlopenMissingError: `= ${dlopenMissingError}`,
_dlopen_js__deps: ['$dlopenMissingError'],
_emscripten_dlopen_js__deps: ['$dlopenMissingError'],
_dlsym_js__deps: ['$dlopenMissingError'],
_dlsym_catchup_js__deps: ['$dlopenMissingError'],
dlopen__deps: ['$dlopenMissingError'],
emscripten_dlopen__deps: ['$dlopenMissingError'],
__dlsym__deps: ['$dlopenMissingError'],
#endif
_dlopen_js: function(handle) {
abort(dlopenMissingError);
},
_emscripten_dlopen_js: function(handle, onsuccess, onerror, user_data) {
abort(dlopenMissingError);
},
_dlsym_js: function(handle, symbol) {
abort(dlopenMissingError);
},
_dlsym_catchup_js: function(handle, symbolIndex) {
abort(dlopenMissingError);
},
dlopen: function(filename, flags) {
abort(dlopenMissingError);
},
emscripten_dlopen: function(handle, onsuccess, onerror, user_data) {
abort(dlopenMissingError);
},
__dlsym: function(handle, symbol, ra) {
abort(dlopenMissingError);
},
#else // MAIN_MODULE != 0
// dynamic linker/loader (a-la ld.so on ELF systems)
$LDSO__deps: ['$newDSO'],
$LDSO: {
// name -> dso [refcount, name, module, global]; Used by dlopen
loadedLibsByName: {},
// handle -> dso; Used by dlsym
loadedLibsByHandle: {},
init: () => {
#if ASSERTIONS
// This function needs to run after the initial wasmImports object
// as been created.
assert(wasmImports);
#endif
newDSO('__main__', {{{ cDefs.RTLD_DEFAULT }}}, wasmImports);
},
},
$dlSetError__internal: true,
$dlSetError__deps: ['__dl_seterr', '$stringToUTF8OnStack', '$withStackSave'],
$dlSetError: function(msg) {
#if DYLINK_DEBUG
dbg(`dlSetError: ${msg}`);
#endif
withStackSave(() => {
var cmsg = stringToUTF8OnStack(msg);
___dl_seterr(cmsg, 0);
});
},
// We support some amount of allocation during startup in the case of
// dynamic linking, which needs to allocate memory for dynamic libraries that
// are loaded. That has to happen before the main program can start to run,
// because the main program needs those linked in before it runs (so we can't
// use normally malloc from the main program to do these allocations).
//
// Allocate memory even if malloc isn't ready yet. The allocated memory here
// must be zero initialized since its used for all static data, including bss.
$getMemory__noleakcheck: true,
$getMemory__deps: ['$GOT', '__heap_base', '$zeroMemory', 'malloc'],
$getMemory: function(size) {
// After the runtime is initialized, we must only use sbrk() normally.
#if DYLINK_DEBUG
dbg("getMemory: " + size + " runtimeInitialized=" + runtimeInitialized);
#endif
if (runtimeInitialized) {
// Currently we don't support freeing of static data when modules are
// unloaded via dlclose. This function is tagged as `noleakcheck` to
// avoid having this reported as leak.
return zeroMemory(_malloc(size), size);
}
var ret = ___heap_base;
var end = (ret + size + 15) & -16;
#if ASSERTIONS
assert(end <= HEAP8.length, 'failure to getMemory - memory growth etc. is not supported there, call malloc/sbrk directly or increase INITIAL_MEMORY');
#endif
___heap_base = end;
GOT['__heap_base'].value = {{{ to64('end') }}};
return ret;
},
// returns the side module metadata as an object
// { memorySize, memoryAlign, tableSize, tableAlign, neededDynlibs}
$getDylinkMetadata__deps: ['$UTF8ArrayToString'],
$getDylinkMetadata__internal: true,
$getDylinkMetadata: function(binary) {
var offset = 0;
var end = 0;
function getU8() {
return binary[offset++];
}
function getLEB() {
var ret = 0;
var mul = 1;
while (1) {
var byte = binary[offset++];
ret += ((byte & 0x7f) * mul);
mul *= 0x80;
if (!(byte & 0x80)) break;
}
return ret;
}
function getString() {
var len = getLEB();
offset += len;
return UTF8ArrayToString(binary, offset - len, len);
}
/** @param {string=} message */
function failIf(condition, message) {
if (condition) throw new Error(message);
}
var name = 'dylink.0';
if (binary instanceof WebAssembly.Module) {
var dylinkSection = WebAssembly.Module.customSections(binary, name);
if (dylinkSection.length === 0) {
name = 'dylink'
dylinkSection = WebAssembly.Module.customSections(binary, name);
}
failIf(dylinkSection.length === 0, 'need dylink section');
binary = new Uint8Array(dylinkSection[0]);
end = binary.length
} else {
var int32View = new Uint32Array(new Uint8Array(binary.subarray(0, 24)).buffer);
#if SUPPORT_BIG_ENDIAN
var magicNumberFound = int32View[0] == 0x6d736100 || int32View[0] == 0x0061736d;
#else
var magicNumberFound = int32View[0] == 0x6d736100;
#endif
failIf(!magicNumberFound, 'need to see wasm magic number'); // \0asm
// we should see the dylink custom section right after the magic number and wasm version
failIf(binary[8] !== 0, 'need the dylink section to be first')
offset = 9;
var section_size = getLEB(); //section size
end = offset + section_size;
name = getString();
}
var customSection = { neededDynlibs: [], tlsExports: new Set(), weakImports: new Set() };
if (name == 'dylink') {
customSection.memorySize = getLEB();
customSection.memoryAlign = getLEB();
customSection.tableSize = getLEB();
customSection.tableAlign = getLEB();
// shared libraries this module needs. We need to load them first, so that
// current module could resolve its imports. (see tools/shared.py
// WebAssembly.make_shared_library() for "dylink" section extension format)
var neededDynlibsCount = getLEB();
for (var i = 0; i < neededDynlibsCount; ++i) {
var libname = getString();
customSection.neededDynlibs.push(libname);
}
} else {
failIf(name !== 'dylink.0');
var WASM_DYLINK_MEM_INFO = 0x1;
var WASM_DYLINK_NEEDED = 0x2;
var WASM_DYLINK_EXPORT_INFO = 0x3;
var WASM_DYLINK_IMPORT_INFO = 0x4;
var WASM_SYMBOL_TLS = 0x100;
var WASM_SYMBOL_BINDING_MASK = 0x3;
var WASM_SYMBOL_BINDING_WEAK = 0x1;
while (offset < end) {
var subsectionType = getU8();
var subsectionSize = getLEB();
if (subsectionType === WASM_DYLINK_MEM_INFO) {
customSection.memorySize = getLEB();
customSection.memoryAlign = getLEB();
customSection.tableSize = getLEB();
customSection.tableAlign = getLEB();
} else if (subsectionType === WASM_DYLINK_NEEDED) {
var neededDynlibsCount = getLEB();
for (var i = 0; i < neededDynlibsCount; ++i) {
libname = getString();
customSection.neededDynlibs.push(libname);
}
} else if (subsectionType === WASM_DYLINK_EXPORT_INFO) {
var count = getLEB();
while (count--) {
var symname = getString();
var flags = getLEB();
if (flags & WASM_SYMBOL_TLS) {
customSection.tlsExports.add(symname);
}
}
} else if (subsectionType === WASM_DYLINK_IMPORT_INFO) {
var count = getLEB();
while (count--) {
var modname = getString();
var symname = getString();
var flags = getLEB();
if ((flags & WASM_SYMBOL_BINDING_MASK) == WASM_SYMBOL_BINDING_WEAK) {
customSection.weakImports.add(symname);
}
}
} else {
#if ASSERTIONS
err(`unknown dylink.0 subsection: ${subsectionType}`)
#endif
// unknown subsection
offset += subsectionSize;
}
}
}
#if ASSERTIONS
var tableAlign = Math.pow(2, customSection.tableAlign);
assert(tableAlign === 1, `invalid tableAlign ${tableAlign}`);
assert(offset == end);
#endif
#if DYLINK_DEBUG
dbg(`dylink needed:${customSection.neededDynlibs}`);
#endif
return customSection;
},
// Module.symbols <- libModule.symbols (flags.global handler)
$mergeLibSymbols__deps: ['$isSymbolDefined'],
$mergeLibSymbols: function(exports, libName) {
// add symbols into global namespace TODO: weak linking etc.
for (var sym in exports) {
if (!exports.hasOwnProperty(sym)) {
continue;
}
#if ASSERTIONS == 2
if (isSymbolDefined(sym)) {
var curr = wasmImports[sym], next = exports[sym];
// don't warn on functions - might be odr, linkonce_odr, etc.
if (!(typeof curr == 'function' && typeof next == 'function')) {
err("warning: symbol '" + sym + "' from '" + libName + "' already exists (duplicate symbol? or weak linking, which isn't supported yet?)"); // + [curr, ' vs ', next]);
}
}
#endif
// When RTLD_GLOBAL is enabled, the symbols defined by this shared object
// will be made available for symbol resolution of subsequently loaded
// shared objects.
//
// We should copy the symbols (which include methods and variables) from
// SIDE_MODULE to MAIN_MODULE.
const setImport = (target) => {
#if ASYNCIFY
if (target in asyncifyStubs) {
asyncifyStubs[target] = exports[sym]
}
#endif
if (!isSymbolDefined(target)) {
wasmImports[target] = exports[sym];
}
}
setImport(sym);
#if !hasExportedSymbol('main')
// Special case for handling of main symbol: If a side module exports
// `main` that also acts a definition for `__main_argc_argv` and vice
// versa.
const main_alias = '__main_argc_argv';
if (sym == 'main') {
setImport(main_alias)
}
if (sym == main_alias) {
setImport('main')
}
#endif
if (sym.startsWith('dynCall_') && !Module.hasOwnProperty(sym)) {
Module[sym] = exports[sym];
}
}
},
#if DYLINK_DEBUG
$dumpTable: function() {
for (var i = 0; i < wasmTable.length; i++)
dbg(`table: ${i} : ${wasmTable.get(i)}`);
},
#endif
// Loads a side module from binary data or compiled Module. Returns the module's exports or a
// promise that resolves to its exports if the loadAsync flag is set.
$loadWebAssemblyModule__docs: `
/**
* @param {string=} libName
* @param {Object=} localScope
* @param {number=} handle
*/`,
$loadWebAssemblyModule__deps: [
'$loadDynamicLibrary', '$getMemory',
'$relocateExports', '$resolveGlobalSymbol', '$GOTHandler',
'$getDylinkMetadata', '$alignMemory', '$zeroMemory',
'$alignMemory', '$zeroMemory',
'$currentModuleWeakSymbols', '$alignMemory', '$zeroMemory',
'$updateTableMap',
],
$loadWebAssemblyModule: function(binary, flags, libName, localScope, handle) {
#if DYLINK_DEBUG
dbg(`loadWebAssemblyModule: ${libName}`);
#endif
var metadata = getDylinkMetadata(binary);
currentModuleWeakSymbols = metadata.weakImports;
#if ASSERTIONS
var originalTable = wasmTable;
#endif
// loadModule loads the wasm module after all its dependencies have been loaded.
// can be called both sync/async.
function loadModule() {
// The first thread to load a given module needs to allocate the static
// table and memory regions. Later threads re-use the same table region
// and can ignore the memory region (since memory is shared between
// threads already).
// If `handle` is specified than it is assumed that the calling thread has
// exclusive access to it for the duration of this function. See the
// locking in `dynlink.c`.
var firstLoad = !handle || !{{{ makeGetValue('handle', C_STRUCTS.dso.mem_allocated, 'i8') }}};
if (firstLoad) {
// alignments are powers of 2
var memAlign = Math.pow(2, metadata.memoryAlign);
// finalize alignments and verify them
memAlign = Math.max(memAlign, {{{ STACK_ALIGN }}}); // we at least need stack alignment
// prepare memory
var memoryBase = metadata.memorySize ? alignMemory(getMemory(metadata.memorySize + memAlign), memAlign) : 0; // TODO: add to cleanups
var tableBase = metadata.tableSize ? wasmTable.length : 0;
if (handle) {
{{{ makeSetValue('handle', C_STRUCTS.dso.mem_allocated, '1', 'i8') }}};
{{{ makeSetValue('handle', C_STRUCTS.dso.mem_addr, 'memoryBase', '*') }}};
{{{ makeSetValue('handle', C_STRUCTS.dso.mem_size, 'metadata.memorySize', 'i32') }}};
{{{ makeSetValue('handle', C_STRUCTS.dso.table_addr, 'tableBase', '*') }}};
{{{ makeSetValue('handle', C_STRUCTS.dso.table_size, 'metadata.tableSize', 'i32') }}};
}
} else {
memoryBase = {{{ makeGetValue('handle', C_STRUCTS.dso.mem_addr, '*') }}};
tableBase = {{{ makeGetValue('handle', C_STRUCTS.dso.table_addr, '*') }}};
}
var tableGrowthNeeded = tableBase + metadata.tableSize - wasmTable.length;
if (tableGrowthNeeded > 0) {
#if DYLINK_DEBUG
dbg("loadModule: growing table: " + tableGrowthNeeded);
#endif
wasmTable.grow(tableGrowthNeeded);
}
#if DYLINK_DEBUG
dbg("loadModule: memory[" + memoryBase + ":" + (memoryBase + metadata.memorySize) + "]" +
" table[" + tableBase + ":" + (tableBase + metadata.tableSize) + "]");
#endif
// This is the export map that we ultimately return. We declare it here
// so it can be used within resolveSymbol. We resolve symbols against
// this local symbol map in the case there they are not present on the
// global Module object. We need this fallback because Modules sometime
// need to import their own symbols
var moduleExports;
function resolveSymbol(sym) {
var resolved = resolveGlobalSymbol(sym).sym;
if (!resolved && localScope) {
resolved = localScope[sym];
}
if (!resolved) {
resolved = moduleExports[sym];
}
#if ASSERTIONS
assert(resolved, `undefined symbol '${sym}'. perhaps a side module was not linked in? if this global was expected to arrive from a system library, try to build the MAIN_MODULE with EMCC_FORCE_STDLIBS=1 in the environment`);
#endif
return resolved;
}
// TODO kill ↓↓↓ (except "symbols local to this module", it will likely be
// not needed if we require that if A wants symbols from B it has to link
// to B explicitly: similarly to -Wl,--no-undefined)
//
// wasm dynamic libraries are pure wasm, so they cannot assist in
// their own loading. When side module A wants to import something
// provided by a side module B that is loaded later, we need to
// add a layer of indirection, but worse, we can't even tell what
// to add the indirection for, without inspecting what A's imports
// are. To do that here, we use a JS proxy (another option would
// be to inspect the binary directly).
var proxyHandler = {
'get': function(stubs, prop) {
// symbols that should be local to this module
switch (prop) {
case '__memory_base':
return {{{ to64('memoryBase') }}};
case '__table_base':
return {{{ to64('tableBase') }}};
#if MEMORY64
#if MEMORY64 == 2
case '__memory_base32':
return memoryBase;
#endif
case '__table_base32':
return tableBase;
#endif
}
if (prop in wasmImports && !wasmImports[prop].stub) {
// No stub needed, symbol already exists in symbol table
return wasmImports[prop];
}
// Return a stub function that will resolve the symbol
// when first called.
if (!(prop in stubs)) {
var resolved;
stubs[prop] = function() {
if (!resolved) resolved = resolveSymbol(prop);
return resolved.apply(null, arguments);
};
}
return stubs[prop];
}
};
var proxy = new Proxy({}, proxyHandler);
var info = {
'GOT.mem': new Proxy({}, GOTHandler),
'GOT.func': new Proxy({}, GOTHandler),
'env': proxy,
'{{{ WASI_MODULE_NAME }}}': proxy,
};
function postInstantiation(module, instance) {
#if ASSERTIONS
// the table should be unchanged
assert(wasmTable === originalTable);
#endif
#if PTHREADS
if (!ENVIRONMENT_IS_PTHREAD && libName) {
#if DYLINK_DEBUG
dbg(`registering sharedModules: ${libName}`)
#endif
// cache all loaded modules in `sharedModules`, which gets passed
// to new workers when they are created.
sharedModules[libName] = module;
}
#endif
// add new entries to functionsInTableMap
updateTableMap(tableBase, metadata.tableSize);
moduleExports = relocateExports(instance.exports, memoryBase);
#if ASYNCIFY
moduleExports = Asyncify.instrumentWasmExports(moduleExports);
#endif
if (!flags.allowUndefined) {
reportUndefinedSymbols();
}
#if STACK_OVERFLOW_CHECK >= 2
// If the runtime has already been initialized we set the stack limits
// now. Otherwise this is delayed until `setDylinkStackLimits` is
// called after initialization.
if (moduleExports['__set_stack_limits'] && runtimeInitialized) {
moduleExports['__set_stack_limits']({{{ to64('_emscripten_stack_get_base()') }}}, {{{ to64('_emscripten_stack_get_end()') }}});
}
#endif
#if MAIN_MODULE
function addEmAsm(addr, body) {
var args = [];
var arity = 0;
for (; arity < 16; arity++) {
if (body.indexOf('$' + arity) != -1) {
args.push('$' + arity);
} else {
break;
}
}
args = args.join(',');
var func = `(${args}) => { ${body} };`;
#if DYLINK_DEBUG
dbg(`adding new EM_ASM constant at: ${ptrToString(start)}`);
#endif
{{{ makeEval('ASM_CONSTS[start] = eval(func)') }}};
}
// Add any EM_ASM function that exist in the side module
if ('__start_em_asm' in moduleExports) {
var start = moduleExports['__start_em_asm'];
var stop = moduleExports['__stop_em_asm'];
{{{ from64('start') }}}
{{{ from64('stop') }}}
while (start < stop) {
var jsString = UTF8ToString(start);
addEmAsm(start, jsString);
start = HEAPU8.indexOf(0, start) + 1;
}
}
#endif
// initialize the module
#if PTHREADS
// Only one thread should call __wasm_call_ctors, but all threads need
// to call _emscripten_tls_init
registerTLSInit(moduleExports['_emscripten_tls_init'], instance.exports, metadata)
if (firstLoad) {
#endif
var applyRelocs = moduleExports['__wasm_apply_data_relocs'];
if (applyRelocs) {
if (runtimeInitialized) {
#if DYLINK_DEBUG
dbg('applyRelocs');
#endif
applyRelocs();
} else {
__RELOC_FUNCS__.push(applyRelocs);
}
}
var init = moduleExports['__wasm_call_ctors'];
if (init) {
if (runtimeInitialized) {
init();
} else {
// we aren't ready to run compiled code yet
__ATINIT__.push(init);
}
}
#if PTHREADS
}
#endif
return moduleExports;
}
if (flags.loadAsync) {
if (binary instanceof WebAssembly.Module) {
var instance = new WebAssembly.Instance(binary, info);
return Promise.resolve(postInstantiation(binary, instance));
}
return WebAssembly.instantiate(binary, info).then(
(result) => postInstantiation(result.module, result.instance)
);
}
var module = binary instanceof WebAssembly.Module ? binary : new WebAssembly.Module(binary);
var instance = new WebAssembly.Instance(module, info);
return postInstantiation(module, instance);
}
// now load needed libraries and the module itself.
if (flags.loadAsync) {
return metadata.neededDynlibs.reduce((chain, dynNeeded) => {
return chain.then(() => {
return loadDynamicLibrary(dynNeeded, flags);
});
}, Promise.resolve()).then(loadModule);
}
metadata.neededDynlibs.forEach((needed) => loadDynamicLibrary(needed, flags, localScope));
return loadModule();
},
#if STACK_OVERFLOW_CHECK >= 2
// Sometimes we load libraries before runtime initialization. In this case
// we delay calling __set_stack_limits (which must be called for each
// module).
$setDylinkStackLimits: function(stackTop, stackMax) {
for (var name in LDSO.loadedLibsByName) {
#if DYLINK_DEBUG
dbg(`setDylinkStackLimits for '${name}'`);
#endif
var lib = LDSO.loadedLibsByName[name];
if (lib.exports['__set_stack_limits']) {
lib.exports['__set_stack_limits']({{{ to64("stackTop") }}}, {{{ to64("stackMax") }}});
}
}
},
#endif
$newDSO: function(name, handle, syms) {
var dso = {
refcount: Infinity,
name: name,
exports: syms,
global: true,
};
LDSO.loadedLibsByName[name] = dso;
if (handle != undefined) {
LDSO.loadedLibsByHandle[handle] = dso;
}
return dso;
},
// loadDynamicLibrary loads dynamic library @ lib URL / path and returns
// handle for loaded DSO.
//
// Several flags affect the loading:
//
// - if flags.global=true, symbols from the loaded library are merged into global
// process namespace. Flags.global is thus similar to RTLD_GLOBAL in ELF.
//
// - if flags.nodelete=true, the library will be never unloaded. Flags.nodelete
// is thus similar to RTLD_NODELETE in ELF.
//
// - if flags.loadAsync=true, the loading is performed asynchronously and
// loadDynamicLibrary returns corresponding promise.
//
// If a library was already loaded, it is not loaded a second time. However
// flags.global and flags.nodelete are handled every time a load request is made.
// Once a library becomes "global" or "nodelete", it cannot be removed or unloaded.
$loadDynamicLibrary__deps: ['$LDSO', '$loadWebAssemblyModule',
'$isInternalSym', '$mergeLibSymbols', '$newDSO',
'$asyncLoad',
#if FILESYSTEM
'$preloadedWasm',
#endif
],
$loadDynamicLibrary__docs: `
/**
* @param {number=} handle
* @param {Object=} localScope
*/`,
$loadDynamicLibrary: function(libName, flags = {global: true, nodelete: true}, localScope, handle) {
#if DYLINK_DEBUG
dbg(`loadDynamicLibrary: ${libName} handle: ${handle}`);
dbg(`existing: ${Object.keys(LDSO.loadedLibsByName)}`);
#endif
// when loadDynamicLibrary did not have flags, libraries were loaded
// globally & permanently
var dso = LDSO.loadedLibsByName[libName];
if (dso) {
// the library is being loaded or has been loaded already.
//
// however it could be previously loaded only locally and if we get
// load request with global=true we have to make it globally visible now.
if (flags.global && !dso.global) {
dso.global = true;
if (dso.exports !== 'loading') {
// ^^^ if module is 'loading' - symbols merging will be eventually done by the loader.
mergeLibSymbols(dso.exports, libName)
}
}
// same for "nodelete"
if (flags.nodelete && dso.refcount !== Infinity) {
dso.refcount = Infinity;
}
dso.refcount++
if (handle) {
LDSO.loadedLibsByHandle[handle] = dso;
}
return flags.loadAsync ? Promise.resolve(true) : true;
}
// allocate new DSO
dso = newDSO(libName, handle, 'loading');
dso.refcount = flags.nodelete ? Infinity : 1;
dso.global = flags.global;
// libName -> libData
function loadLibData() {
#if PTHREADS
var sharedMod = sharedModules[libName];
#if DYLINK_DEBUG
dbg(`checking sharedModules: ${libName}: ${sharedMod ? 'found' : 'not found'}`);
#endif
if (sharedMod) {
return flags.loadAsync ? Promise.resolve(sharedMod) : sharedMod;
}
#endif
// for wasm, we can use fetch for async, but for fs mode we can only imitate it
if (handle) {
var data = {{{ makeGetValue('handle', C_STRUCTS.dso.file_data, '*') }}};
var dataSize = {{{ makeGetValue('handle', C_STRUCTS.dso.file_data_size, '*') }}};
if (data && dataSize) {
var libData = HEAP8.slice(data, data + dataSize);