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rOACCT/node_modules/webpack/lib/wasm-sync/WebAssemblyGenerator.js
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WebAssemblyGenerator.js
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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const { RawSource } = require("webpack-sources");
const Generator = require("../Generator");
const WebAssemblyUtils = require("./WebAssemblyUtils");
const t = require("@webassemblyjs/ast");
const {
moduleContextFromModuleAST
} = require("@webassemblyjs/helper-module-context");
const { editWithAST, addWithAST } = require("@webassemblyjs/wasm-edit");
const { decode } = require("@webassemblyjs/wasm-parser");
const WebAssemblyExportImportedDependency = require("../dependencies/WebAssemblyExportImportedDependency");
/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("../DependencyTemplates")} DependencyTemplates */
/** @typedef {import("../Generator").GenerateContext} GenerateContext */
/** @typedef {import("../Module")} Module */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../NormalModule")} NormalModule */
/** @typedef {import("../RuntimeTemplate")} RuntimeTemplate */
/** @typedef {import("../util/runtime").RuntimeSpec} RuntimeSpec */
/** @typedef {import("./WebAssemblyUtils").UsedWasmDependency} UsedWasmDependency */
/**
* @typedef {(ArrayBuffer) => ArrayBuffer} ArrayBufferTransform
*/
/**
* @template T
* @param {Function[]} fns transforms
* @returns {Function} composed transform
*/
const compose = (...fns) => {
return fns.reduce(
(prevFn, nextFn) => {
return value => nextFn(prevFn(value));
},
value => value
);
};
/**
* Removes the start instruction
*
* @param {Object} state unused state
* @returns {ArrayBufferTransform} transform
*/
const removeStartFunc = state => bin => {
return editWithAST(state.ast, bin, {
Start(path) {
path.remove();
}
});
};
/**
* Get imported globals
*
* @param {Object} ast Module's AST
* @returns {Array<t.ModuleImport>} - nodes
*/
const getImportedGlobals = ast => {
const importedGlobals = [];
t.traverse(ast, {
ModuleImport({ node }) {
if (t.isGlobalType(node.descr)) {
importedGlobals.push(node);
}
}
});
return importedGlobals;
};
/**
* Get the count for imported func
*
* @param {Object} ast Module's AST
* @returns {Number} - count
*/
const getCountImportedFunc = ast => {
let count = 0;
t.traverse(ast, {
ModuleImport({ node }) {
if (t.isFuncImportDescr(node.descr)) {
count++;
}
}
});
return count;
};
/**
* Get next type index
*
* @param {Object} ast Module's AST
* @returns {t.Index} - index
*/
const getNextTypeIndex = ast => {
const typeSectionMetadata = t.getSectionMetadata(ast, "type");
if (typeSectionMetadata === undefined) {
return t.indexLiteral(0);
}
return t.indexLiteral(typeSectionMetadata.vectorOfSize.value);
};
/**
* Get next func index
*
* The Func section metadata provide informations for implemented funcs
* in order to have the correct index we shift the index by number of external
* functions.
*
* @param {Object} ast Module's AST
* @param {Number} countImportedFunc number of imported funcs
* @returns {t.Index} - index
*/
const getNextFuncIndex = (ast, countImportedFunc) => {
const funcSectionMetadata = t.getSectionMetadata(ast, "func");
if (funcSectionMetadata === undefined) {
return t.indexLiteral(0 + countImportedFunc);
}
const vectorOfSize = funcSectionMetadata.vectorOfSize.value;
return t.indexLiteral(vectorOfSize + countImportedFunc);
};
/**
* Creates an init instruction for a global type
* @param {t.GlobalType} globalType the global type
* @returns {t.Instruction} init expression
*/
const createDefaultInitForGlobal = globalType => {
if (globalType.valtype[0] === "i") {
// create NumberLiteral global initializer
return t.objectInstruction("const", globalType.valtype, [
t.numberLiteralFromRaw(66)
]);
} else if (globalType.valtype[0] === "f") {
// create FloatLiteral global initializer
return t.objectInstruction("const", globalType.valtype, [
t.floatLiteral(66, false, false, "66")
]);
} else {
throw new Error("unknown type: " + globalType.valtype);
}
};
/**
* Rewrite the import globals:
* - removes the ModuleImport instruction
* - injects at the same offset a mutable global of the same type
*
* Since the imported globals are before the other global declarations, our
* indices will be preserved.
*
* Note that globals will become mutable.
*
* @param {Object} state unused state
* @returns {ArrayBufferTransform} transform
*/
const rewriteImportedGlobals = state => bin => {
const additionalInitCode = state.additionalInitCode;
const newGlobals = [];
bin = editWithAST(state.ast, bin, {
ModuleImport(path) {
if (t.isGlobalType(path.node.descr)) {
const globalType = path.node.descr;
globalType.mutability = "var";
const init = [
createDefaultInitForGlobal(globalType),
t.instruction("end")
];
newGlobals.push(t.global(globalType, init));
path.remove();
}
},
// in order to preserve non-imported global's order we need to re-inject
// those as well
Global(path) {
const { node } = path;
const [init] = node.init;
if (init.id === "get_global") {
node.globalType.mutability = "var";
const initialGlobalIdx = init.args[0];
node.init = [
createDefaultInitForGlobal(node.globalType),
t.instruction("end")
];
additionalInitCode.push(
/**
* get_global in global initializer only works for imported globals.
* They have the same indices as the init params, so use the
* same index.
*/
t.instruction("get_local", [initialGlobalIdx]),
t.instruction("set_global", [t.indexLiteral(newGlobals.length)])
);
}
newGlobals.push(node);
path.remove();
}
});
// Add global declaration instructions
return addWithAST(state.ast, bin, newGlobals);
};
/**
* Rewrite the export names
* @param {Object} state state
* @param {Object} state.ast Module's ast
* @param {Module} state.module Module
* @param {ModuleGraph} state.moduleGraph module graph
* @param {Set<string>} state.externalExports Module
* @param {RuntimeSpec} state.runtime runtime
* @returns {ArrayBufferTransform} transform
*/
const rewriteExportNames = ({
ast,
moduleGraph,
module,
externalExports,
runtime
}) => bin => {
return editWithAST(ast, bin, {
ModuleExport(path) {
const isExternal = externalExports.has(path.node.name);
if (isExternal) {
path.remove();
return;
}
const usedName = moduleGraph
.getExportsInfo(module)
.getUsedName(path.node.name, runtime);
if (!usedName) {
path.remove();
return;
}
path.node.name = usedName;
}
});
};
/**
* Mangle import names and modules
* @param {Object} state state
* @param {Object} state.ast Module's ast
* @param {Map<string, UsedWasmDependency>} state.usedDependencyMap mappings to mangle names
* @returns {ArrayBufferTransform} transform
*/
const rewriteImports = ({ ast, usedDependencyMap }) => bin => {
return editWithAST(ast, bin, {
ModuleImport(path) {
const result = usedDependencyMap.get(
path.node.module + ":" + path.node.name
);
if (result !== undefined) {
path.node.module = result.module;
path.node.name = result.name;
}
}
});
};
/**
* Add an init function.
*
* The init function fills the globals given input arguments.
*
* @param {Object} state transformation state
* @param {Object} state.ast Module's ast
* @param {t.Identifier} state.initFuncId identifier of the init function
* @param {t.Index} state.startAtFuncOffset index of the start function
* @param {t.ModuleImport[]} state.importedGlobals list of imported globals
* @param {t.Instruction[]} state.additionalInitCode list of addition instructions for the init function
* @param {t.Index} state.nextFuncIndex index of the next function
* @param {t.Index} state.nextTypeIndex index of the next type
* @returns {ArrayBufferTransform} transform
*/
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(importedGlobal.descr.valtype, id);
});
const funcBody = [];
importedGlobals.forEach((importedGlobal, index) => {
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"));
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);
// Export section
const moduleExport = t.moduleExport(
initFuncId.value,
t.moduleExportDescr("Func", nextFuncIndex)
);
return addWithAST(ast, bin, [func, moduleExport, funcindex, functype]);
};
/**
* Extract mangle mappings from module
* @param {ModuleGraph} moduleGraph module graph
* @param {Module} module current module
* @param {boolean} mangle mangle imports
* @returns {Map<string, UsedWasmDependency>} mappings to mangled names
*/
const getUsedDependencyMap = (moduleGraph, module, mangle) => {
/** @type {Map<string, UsedWasmDependency>} */
const map = new Map();
for (const usedDep of WebAssemblyUtils.getUsedDependencies(
moduleGraph,
module,
mangle
)) {
const dep = usedDep.dependency;
const request = dep.request;
const exportName = dep.name;
map.set(request + ":" + exportName, usedDep);
}
return map;
};
const TYPES = new Set(["webassembly"]);
class WebAssemblyGenerator extends Generator {
constructor(options) {
super();
this.options = options;
}
/**
* @param {NormalModule} module fresh module
* @returns {Set<string>} available types (do not mutate)
*/
getTypes(module) {
return TYPES;
}
/**
* @param {NormalModule} module the module
* @param {string=} type source type
* @returns {number} estimate size of the module
*/
getSize(module, type) {
const originalSource = module.originalSource();
if (!originalSource) {
return 0;
}
return originalSource.size();
}
/**
* @param {NormalModule} module module for which the code should be generated
* @param {GenerateContext} generateContext context for generate
* @returns {Source} generated code
*/
generate(module, { moduleGraph, runtime }) {
const bin = module.originalSource().source();
const initFuncId = t.identifier("");
// parse it
const ast = decode(bin, {
ignoreDataSection: true,
ignoreCodeSection: true,
ignoreCustomNameSection: true
});
const moduleContext = moduleContextFromModuleAST(ast.body[0]);
const importedGlobals = getImportedGlobals(ast);
const countImportedFunc = getCountImportedFunc(ast);
const startAtFuncOffset = moduleContext.getStart();
const nextFuncIndex = getNextFuncIndex(ast, countImportedFunc);
const nextTypeIndex = getNextTypeIndex(ast);
const usedDependencyMap = getUsedDependencyMap(
moduleGraph,
module,
this.options.mangleImports
);
const externalExports = new Set(
module.dependencies
.filter(d => d instanceof WebAssemblyExportImportedDependency)
.map(d => {
const wasmDep = /** @type {WebAssemblyExportImportedDependency} */ (d);
return wasmDep.exportName;
})
);
/** @type {t.Instruction[]} */
const additionalInitCode = [];
const transform = compose(
rewriteExportNames({
ast,
moduleGraph,
module,
externalExports,
runtime
}),
removeStartFunc({ ast }),
rewriteImportedGlobals({ ast, additionalInitCode }),
rewriteImports({
ast,
usedDependencyMap
}),
addInitFunction({
ast,
initFuncId,
importedGlobals,
additionalInitCode,
startAtFuncOffset,
nextFuncIndex,
nextTypeIndex
})
);
const newBin = transform(bin);
const newBuf = Buffer.from(newBin);
return new RawSource(newBuf);
}
}
module.exports = WebAssemblyGenerator;
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