78 lines
2.8 KiB
JavaScript
78 lines
2.8 KiB
JavaScript
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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} |