107 lines
3.2 KiB
JavaScript
107 lines
3.2 KiB
JavaScript
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function _typeof(obj) { if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }
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import { encodeNode } from "@webassemblyjs/wasm-gen";
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import { overrideBytesInBuffer } from "@webassemblyjs/helper-buffer";
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import constants from "@webassemblyjs/helper-wasm-bytecode";
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import * as t from "@webassemblyjs/ast";
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function findLastSection(ast, forSection) {
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var targetSectionId = constants.sections[forSection]; // $FlowIgnore: metadata can not be empty
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var moduleSections = ast.body[0].metadata.sections;
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var lastSection;
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var lastId = 0;
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for (var i = 0, len = moduleSections.length; i < len; i++) {
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var section = moduleSections[i]; // Ignore custom section since they can actually occur everywhere
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if (section.section === "custom") {
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continue;
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}
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var sectionId = constants.sections[section.section];
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if (targetSectionId > lastId && targetSectionId < sectionId) {
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return lastSection;
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}
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lastId = sectionId;
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lastSection = section;
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}
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return lastSection;
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}
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export function createEmptySection(ast, uint8Buffer, section) {
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// previous section after which we are going to insert our section
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var lastSection = findLastSection(ast, section);
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var start, end;
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/**
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* It's the first section
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*/
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if (lastSection == null || lastSection.section === "custom") {
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start = 8
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/* wasm header size */
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;
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end = start;
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} else {
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start = lastSection.startOffset + lastSection.size.value + 1;
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end = start;
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} // section id
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start += 1;
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var sizeStartLoc = {
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line: -1,
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column: start
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};
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var sizeEndLoc = {
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line: -1,
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column: start + 1
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}; // 1 byte for the empty vector
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var size = t.withLoc(t.numberLiteralFromRaw(1), sizeEndLoc, sizeStartLoc);
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var vectorOfSizeStartLoc = {
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line: -1,
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column: sizeEndLoc.column
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};
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var vectorOfSizeEndLoc = {
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line: -1,
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column: sizeEndLoc.column + 1
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};
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var vectorOfSize = t.withLoc(t.numberLiteralFromRaw(0), vectorOfSizeEndLoc, vectorOfSizeStartLoc);
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var sectionMetadata = t.sectionMetadata(section, start, size, vectorOfSize);
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var sectionBytes = encodeNode(sectionMetadata);
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uint8Buffer = overrideBytesInBuffer(uint8Buffer, start - 1, end, sectionBytes); // Add section into the AST for later lookups
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if (_typeof(ast.body[0].metadata) === "object") {
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// $FlowIgnore: metadata can not be empty
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ast.body[0].metadata.sections.push(sectionMetadata);
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t.sortSectionMetadata(ast.body[0]);
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}
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/**
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* Update AST
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*/
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// Once we hit our section every that is after needs to be shifted by the delta
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var deltaBytes = +sectionBytes.length;
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var encounteredSection = false;
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t.traverse(ast, {
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SectionMetadata: function SectionMetadata(path) {
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if (path.node.section === section) {
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encounteredSection = true;
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return;
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}
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if (encounteredSection === true) {
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t.shiftSection(ast, path.node, deltaBytes);
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}
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}
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});
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return {
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uint8Buffer: uint8Buffer,
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sectionMetadata: sectionMetadata
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};
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}
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