1 | 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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2 |
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3 | import { encodeNode } from "@webassemblyjs/wasm-gen";
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4 | import { overrideBytesInBuffer } from "@webassemblyjs/helper-buffer";
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5 | import constants from "@webassemblyjs/helper-wasm-bytecode";
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6 | import * as t from "@webassemblyjs/ast";
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7 |
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8 | function findLastSection(ast, forSection) {
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9 | var targetSectionId = constants.sections[forSection]; // $FlowIgnore: metadata can not be empty
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10 |
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11 | var moduleSections = ast.body[0].metadata.sections;
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12 | var lastSection;
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13 | var lastId = 0;
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14 |
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15 | for (var i = 0, len = moduleSections.length; i < len; i++) {
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16 | var section = moduleSections[i]; // Ignore custom section since they can actually occur everywhere
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17 |
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18 | if (section.section === "custom") {
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19 | continue;
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20 | }
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21 |
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22 | var sectionId = constants.sections[section.section];
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23 |
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24 | if (targetSectionId > lastId && targetSectionId < sectionId) {
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25 | return lastSection;
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26 | }
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27 |
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28 | lastId = sectionId;
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29 | lastSection = section;
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30 | }
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31 |
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32 | return lastSection;
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33 | }
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34 |
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35 | export function createEmptySection(ast, uint8Buffer, section) {
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36 | // previous section after which we are going to insert our section
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37 | var lastSection = findLastSection(ast, section);
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38 | var start, end;
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39 | /**
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40 | * It's the first section
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41 | */
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42 |
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43 | if (lastSection == null || lastSection.section === "custom") {
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44 | start = 8
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45 | /* wasm header size */
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46 | ;
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47 | end = start;
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48 | } else {
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49 | start = lastSection.startOffset + lastSection.size.value + 1;
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50 | end = start;
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51 | } // section id
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52 |
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53 |
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54 | start += 1;
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55 | var sizeStartLoc = {
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56 | line: -1,
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57 | column: start
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58 | };
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59 | var sizeEndLoc = {
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60 | line: -1,
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61 | column: start + 1
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62 | }; // 1 byte for the empty vector
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63 |
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64 | var size = t.withLoc(t.numberLiteralFromRaw(1), sizeEndLoc, sizeStartLoc);
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65 | var vectorOfSizeStartLoc = {
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66 | line: -1,
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67 | column: sizeEndLoc.column
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68 | };
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69 | var vectorOfSizeEndLoc = {
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70 | line: -1,
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71 | column: sizeEndLoc.column + 1
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72 | };
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73 | var vectorOfSize = t.withLoc(t.numberLiteralFromRaw(0), vectorOfSizeEndLoc, vectorOfSizeStartLoc);
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74 | var sectionMetadata = t.sectionMetadata(section, start, size, vectorOfSize);
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75 | var sectionBytes = encodeNode(sectionMetadata);
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76 | uint8Buffer = overrideBytesInBuffer(uint8Buffer, start - 1, end, sectionBytes); // Add section into the AST for later lookups
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77 |
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78 | if (_typeof(ast.body[0].metadata) === "object") {
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79 | // $FlowIgnore: metadata can not be empty
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80 | ast.body[0].metadata.sections.push(sectionMetadata);
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81 | t.sortSectionMetadata(ast.body[0]);
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82 | }
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83 | /**
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84 | * Update AST
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85 | */
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86 | // Once we hit our section every that is after needs to be shifted by the delta
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87 |
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88 |
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89 | var deltaBytes = +sectionBytes.length;
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90 | var encounteredSection = false;
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91 | t.traverse(ast, {
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92 | SectionMetadata: function SectionMetadata(path) {
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93 | if (path.node.section === section) {
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94 | encounteredSection = true;
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95 | return;
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96 | }
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97 |
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98 | if (encounteredSection === true) {
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99 | t.shiftSection(ast, path.node, deltaBytes);
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100 | }
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101 | }
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102 | });
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103 | return {
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104 | uint8Buffer: uint8Buffer,
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105 | sectionMetadata: sectionMetadata
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106 | };
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107 | } |
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