wasm-metering

<!doctype html> <html lang="en"> <head> <title>Code coverage report for index.js</title> <meta charset="utf-8" /> <link rel="stylesheet" href="prettify.css" /> <link rel="stylesheet" href="base.css" /> <meta name="viewport" content="width=device-width, initial-scale=1"> <style type='text/css'> .coverage-summary .sorter { background-image: url(sort-arrow-sprite.png); } </style> </head> <body> <div class='wrapper'> <div class='pad1'> <h1> <a href="index.html">All files</a> index.js </h1> <div class='clearfix'> <div class='fl pad1y space-right2'> 100% Statements 111/111 </div> <div class='fl pad1y space-right2'> 98.28% Branches 57/58 </div> <div class='fl pad1y space-right2'> 100% Functions 13/13 </div> <div class='fl pad1y space-right2'> 100% Lines 102/102 </div> </div> </div> <div class='status-line high'></div> <pre><table class="coverage"> <tr><td class="line-count quiet">1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223</td><td class="line-coverage quiet">2x 2x 2x 2x       272x   272x   272x 48x 24x   224x 24x 64x 64x 40x     200x 190x   10x   272x           58x     112x 4x       24x   24x 48x         24x 24x 24x 24x   24x   24x 36x     36x 112x 112x   112x 112x 36x         36x   34x 34x         36x   36x 36x     24x 24x                         2x   148x       20x 20x 54x 54x 54x 34x   20x       20x           24x     24x     24x 24x 24x 24x     24x 24x   24x         24x         24x   24x 152x 152x     24x   24x 24x     16x 16x   24x 14x 2x   12x 10x       22x 22x   16x 20x 16x     16x   2x   10x   2x     4x 4x   16x 24x 24x 24x 24x   24x   16x       22x                         2x 2x 2x 2x    </td><td class="text"><pre class="prettyprint lang-js">const toolkit = require('wasm-json-toolkit') const text2json = toolkit.text2json const SECTION_IDS = require('wasm-json-toolkit/json2wasm').SECTION_IDS const defaultCostTable = require('./defaultCostTable.json')   // gets the cost of an operation for entry in a section from the cost table function getCost (json, costTable = {}, defaultCost = 0) { let cost = 0 // finds the default cost defaultCost = costTable['DEFAULT'] !== undefined ? costTable['DEFAULT'] : 0   if (Array.isArray(json)) { json.forEach(el => { cost += getCost(el, costTable) }) } else if (typeof json === 'object') { for (const propName in json) { const propCost = costTable[propName] if (propCost) { cost += getCost(json[propName], propCost, defaultCost) } } } else if (costTable[json] === undefined) { cost = defaultCost } else { cost = costTable[json] } return cost }   // meters a single code entrie function meterCodeEntry (entry, costTable, meterFuncIndex, meterType, cost) { function meteringStatement (cost, meteringImportIndex) { return text2json(`${meterType}.const ${cost} call ${meteringImportIndex}`) } function remapOp (op, funcIndex) { if (op.name === 'call' && op.immediates >= funcIndex) { op.immediates = (++op.immediates).toString() } } function meterTheMeteringStatement () { const code = meteringStatement(0, 0) // sum the operations cost return code.reduce( (sum, op) => sum + getCost(op.name, costTable.code) , 0) }   // operations that can possible cause a branch const branchingOps = new Set(['grow_memory', 'end', 'br', 'br_table', 'br_if', 'if', 'else', 'return', 'loop']) const meteringOverHead = meterTheMeteringStatement() let code = entry.code.slice() let meteredCode = []   cost += getCost(entry.locals, costTable.local)   while (code.length) { let i = 0   // meters a segment of wasm code while (true) { const op = code[i++] remapOp(op, meterFuncIndex)   cost += getCost(op.name, costTable.code) if (branchingOps.has(op.name)) { break } }   // add the metering statement if (cost !== 0) { // add the cost of metering cost += meteringOverHead meteredCode = meteredCode .concat(meteringStatement(cost, meterFuncIndex)) }   // start a new segment meteredCode = meteredCode .concat(code.slice(0, i)) code = code.slice(i) cost = 0 }   entry.code = meteredCode return entry }   /** * Injects metering into a JSON output of [wasm2json](https://github.com/ewasm/wasm-json-toolkit#wasm2json) * @param {Object} json the json tobe metered * @param {Object} opts * @param {Object} [opts.costTable=defaultTable] the cost table to meter with. See these notes about the default. * @param {String} [opts.moduleStr='metering'] the import string for the metering function * @param {String} [opts.fieldStr='usegas'] the field string for the metering function * @param {String} [opts.meterType='i64'] the regerster type that is used to meter. Can be `i64`, `i32`, `f64`, `f32` * @return {Object} the metered json */ exports.meterJSON = (json, opts) => { function findSection (module, sectionName) { return module.find(section => section.name === sectionName) }   function createSection (module, name) { const newSectionId = SECTION_IDS[name] for (let index in module) { const section = module[index] const sectionId = SECTION_IDS[section.name] if (sectionId) { if (newSectionId < sectionId) { // inject a new section module.splice(index, 0, { name, entries: [] }) return } } } }   let funcIndex = 0 let functionModule, typeModule   let {costTable, moduleStr, fieldStr, meterType} = opts   // set defaults if (!costTable) costTable = defaultCostTable if (!moduleStr) moduleStr = 'metering' if (!fieldStr) fieldStr = 'usegas' if (!meterType) meterType = 'i32'   // add nessicarry sections iff they don't exist if (!findSection(json, 'type')) createSection(json, 'type') if (!findSection(json, 'import')) createSection(json, 'import')   const importJson = { 'moduleStr': moduleStr, 'fieldStr': fieldStr, 'kind': 'function' } const importType = { 'form': 'func', 'params': [meterType] }   json = json.slice(0)   for (let section of json) { section = Object.assign(section) switch (section.name) { case 'type': // mark the import index importJson.type = section.entries.push(importType) - 1 // save for use for the code section typeModule = section break case 'function': // save for use for the code section functionModule = section break case 'import': for (const entry of section.entries) { if (entry.moduleStr === moduleStr && entry.fieldStr === fieldStr) { throw new Error('importing meteing function is not allowed') } if (entry.kind === 'function') { funcIndex++ } } // append the metering import section.entries.push(importJson) break case 'export': for (const entry of section.entries) { if (entry.kind === 'function' && entry.index >= funcIndex) { entry.index++ } } break case 'element': for (const entry of section.entries) { // remap elements indices entry.elements = entry.elements.map(el => el >= funcIndex ? ++el : el) } break case 'start': // remap start index if (section.index >= funcIndex) section.index++ break case 'code': for (const i in section.entries) { const entry = section.entries[i] const typeIndex = functionModule.entries[i] const type = typeModule.entries[typeIndex] const cost = getCost(type, costTable.type)   meterCodeEntry(entry, costTable.code, funcIndex, meterType, cost) } break } }   return json }   /** * Injects metering into a webassembly binary * @param {Object} json the json tobe metered * @param {Object} opts * @param {Object} [opts.costTable=defaultTable] the cost table to meter with. See these notes about the default. * @param {String} [opts.moduleStr='metering'] the import string for the metering function * @param {String} [opts.fieldStr='usegas'] the field string for the metering function * @param {String} [opts.meterType='i64'] the regerster type that is used to meter. Can be `i64`, `i32`, `f64`, `f32` * @return {Buffer} */ exports.meterWASM = (wasm, opts = {}) => { let json = toolkit.wasm2json(wasm) json = exports.meterJSON(json, opts) return toolkit.json2wasm(json) }  </pre></td></tr> </table></pre> <div class='push'></div> </div> <div class='footer quiet pad2 space-top1 center small'> Code coverage generated by <a href="https://istanbul.js.org/" target="_blank">istanbul</a> at Thu Apr 05 2018 17:48:46 GMT-0400 (EDT) </div> </div> <script src="prettify.js"></script> <script> window.onload = function () { if (typeof prettyPrint === 'function') { prettyPrint(); } }; </script> <script src="sorter.js"></script> </body> </html>