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78 lines
2.8 KiB
78 lines
2.8 KiB
import { encodeU32 } from "@webassemblyjs/wasm-gen"; |
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import { getSectionMetadata, traverse, shiftSection } from "@webassemblyjs/ast"; |
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import { overrideBytesInBuffer } from "@webassemblyjs/helper-buffer"; |
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export function resizeSectionByteSize(ast, uint8Buffer, section, deltaBytes) { |
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var sectionMetadata = getSectionMetadata(ast, section); |
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if (typeof sectionMetadata === "undefined") { |
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throw new Error("Section metadata not found"); |
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} |
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if (typeof sectionMetadata.size.loc === "undefined") { |
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throw new Error("SectionMetadata " + section + " has no loc"); |
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} // keep old node location to be overriden |
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var start = sectionMetadata.size.loc.start.column; |
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var end = sectionMetadata.size.loc.end.column; |
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var newSectionSize = sectionMetadata.size.value + deltaBytes; |
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var newBytes = encodeU32(newSectionSize); |
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/** |
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* update AST |
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*/ |
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sectionMetadata.size.value = newSectionSize; |
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var oldu32EncodedLen = end - start; |
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var newu32EncodedLen = newBytes.length; // the new u32 has a different encoded length |
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if (newu32EncodedLen !== oldu32EncodedLen) { |
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var deltaInSizeEncoding = newu32EncodedLen - oldu32EncodedLen; |
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sectionMetadata.size.loc.end.column = start + newu32EncodedLen; |
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deltaBytes += deltaInSizeEncoding; // move the vec size pointer size the section size is now smaller |
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sectionMetadata.vectorOfSize.loc.start.column += deltaInSizeEncoding; |
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sectionMetadata.vectorOfSize.loc.end.column += deltaInSizeEncoding; |
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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 encounteredSection = false; |
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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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shiftSection(ast, path.node, deltaBytes); |
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} |
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} |
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}); |
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return overrideBytesInBuffer(uint8Buffer, start, end, newBytes); |
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} |
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export function resizeSectionVecSize(ast, uint8Buffer, section, deltaElements) { |
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var sectionMetadata = getSectionMetadata(ast, section); |
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if (typeof sectionMetadata === "undefined") { |
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throw new Error("Section metadata not found"); |
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} |
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if (typeof sectionMetadata.vectorOfSize.loc === "undefined") { |
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throw new Error("SectionMetadata " + section + " has no loc"); |
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} // Section has no vector |
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if (sectionMetadata.vectorOfSize.value === -1) { |
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return uint8Buffer; |
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} // keep old node location to be overriden |
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var start = sectionMetadata.vectorOfSize.loc.start.column; |
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var end = sectionMetadata.vectorOfSize.loc.end.column; |
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var newValue = sectionMetadata.vectorOfSize.value + deltaElements; |
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var newBytes = encodeU32(newValue); // Update AST |
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sectionMetadata.vectorOfSize.value = newValue; |
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sectionMetadata.vectorOfSize.loc.end.column = start + newBytes.length; |
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return overrideBytesInBuffer(uint8Buffer, start, end, newBytes); |
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} |