Function addInitFunction

lib/wasm-sync/WebAssemblyGenerator.js:325–391

({
		ast,
		initFuncId,
		startAtFuncOffset,
		importedGlobals,
		additionalInitCode,
		nextFuncIndex,
		nextTypeIndex
	})

 */
const addInitFunction =
	({
		ast,
		initFuncId,
		startAtFuncOffset,
		importedGlobals,
		additionalInitCode,
		nextFuncIndex,
		nextTypeIndex
	}) =>
	(bin) => {
		const funcParams = importedGlobals.map((importedGlobal) => {
			// used for debugging
			const id = t.identifier(
				`${importedGlobal.module}.${importedGlobal.name}`
			);

			return t.funcParam(
				/** @type {string} */ (importedGlobal.descr.valtype),
				id
			);
		});

		/** @type {Instruction[]} */
		const funcBody = [];
		for (const [index, _importedGlobal] of importedGlobals.entries()) {
			const args = [t.indexLiteral(index)];
			const body = [
				t.instruction("get_local", args),
				t.instruction("set_global", args)
			];

			funcBody.push(...body);
		}

		if (typeof startAtFuncOffset === "number") {
			funcBody.push(
				t.callInstruction(t.numberLiteralFromRaw(startAtFuncOffset))
			);
		}

		for (const instr of additionalInitCode) {
			funcBody.push(instr);
		}

		funcBody.push(t.instruction("end"));

		/** @type {string[]} */
		const funcResults = [];

		// Code section
		const funcSignature = t.signature(funcParams, funcResults);
		const func = t.func(initFuncId, funcSignature, funcBody);

		// Type section
		const functype = t.typeInstruction(undefined, funcSignature);

		// Func section
		const funcindex = t.indexInFuncSection(nextTypeIndex);