| 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 |
| }; |
| } |