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