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[jsifier] Simplify stub function handling #25519

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Merged
merged 1 commit into from
Oct 7, 2025
+8 −13
Merged

[jsifier] Simplify stub function handling #25519

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21 changes: 8 additions & 13 deletions src/jsifier.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -601,6 +601,9 @@ function(${args}) {
warn('To build in STANDALONE_WASM mode without a main(), use emcc --no-entry');
}
}

// emit a stub that will fail at runtime
var stubFunctionBody = `abort('missing function: ${symbol}');`
if (RELOCATABLE) {
// Create a stub for this symbol which can later be replaced by the
// dynamic linker. If this stub is called before the symbol is
Expand All @@ -615,18 +618,10 @@ function(${args}) {
if (ASSERTIONS) {
assertion += `if (!${target} || ${target}.stub) abort("external symbol '${symbol}' is missing. perhaps a side module was not linked in? if this function was expected to arrive from a system library, try to build the MAIN_MODULE with EMCC_FORCE_STDLIBS=1 in the environment");\n`;
}
const functionBody = assertion + `return ${target}(...args);`;
LibraryManager.library[symbol] = new Function('...args', functionBody);
isStub = true;
} else {
// emit a stub that will fail at runtime
LibraryManager.library[symbol] = new Function(`abort('missing function: ${symbol}');`);
// We have already warned/errored about this function, so for the purposes of Closure use, mute all type checks
// regarding this function, marking ot a variadic function that can take in anything and return anything.
// (not useful to warn/error multiple times)
LibraryManager.library[symbol + '__docs'] = '/** @type {function(...*):?} */';
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Is this not needed for some reason?

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Seems like its no longer needed, since closure can see the ... in the function body I believe.

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Since we are not always creating the stubs with new Function('...args') closure can see that the function variadic.

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Interesting, thanks.

isStub = true;
stubFunctionBody = assertion + `return ${target}(...args);`;
}
isStub = true;
LibraryManager.library[symbol] = new Function('...args', stubFunctionBody);
}

librarySymbols.push(mangled);
Expand All @@ -636,11 +631,11 @@ function(${args}) {

// Check for dependencies on `__internal` symbols from user libraries.
const isUserSymbol = LibraryManager.library[symbol + '__user'];
deps.forEach((dep) => {
for (const dep of deps) {
if (isUserSymbol && LibraryManager.library[dep + '__internal']) {
warn(`user library symbol '${symbol}' depends on internal symbol '${dep}'`);
}
});
}

const isFunction = typeof snippet == 'function';
let isNativeAlias = false;
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