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107 lines
3.2 KiB
107 lines
3.2 KiB
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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} |