The Tor Browser: js/src/devtools/rootAnalysis/analyzeRoots.js@129ffea94266 (annotated)

js/src/devtools/rootAnalysis/analyzeRoots.js@129ffea94266 (annotated)

js/src/devtools/rootAnalysis/analyzeRoots.js

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* -*- Mode: Javascript; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 "use strict";
 loadRelativeToScript('utility.js');
 loadRelativeToScript('annotations.js');
 loadRelativeToScript('CFG.js');
 var sourceRoot = (environment['SOURCE'] || '') + '/'
 var functionBodies;
 if (typeof scriptArgs[0] != 'string' || typeof scriptArgs[1] != 'string')
     throw "Usage: analyzeRoots.js <gcFunctions.lst> <gcEdges.txt> <suppressedFunctions.lst> <gcTypes.txt> [start end [tmpfile]]";
 var gcFunctionsFile = scriptArgs[0];
 var gcEdgesFile = scriptArgs[1];
 var suppressedFunctionsFile = scriptArgs[2];
 var gcTypesFile = scriptArgs[3];
 var batch = (scriptArgs[4]|0) || 1;
 var numBatches = (scriptArgs[5]|0) || 1;
 var tmpfile = scriptArgs[6] || "tmp.txt";
 var gcFunctions = {};
 var text = snarf("gcFunctions.lst").split("\n");
 assert(text.pop().length == 0);
 for (var line of text)
     gcFunctions[mangled(line)] = true;
 var suppressedFunctions = {};
 var text = snarf(suppressedFunctionsFile).split("\n");
 assert(text.pop().length == 0);
 for (var line of text) {
     suppressedFunctions[line] = true;
 }
 text = null;
 var gcEdges = {};
 text = snarf(gcEdgesFile).split('\n');
 assert(text.pop().length == 0);
 for (var line of text) {
     var [ block, edge, func ] = line.split(" || ");
     if (!(block in gcEdges))
         gcEdges[block] = {}
     gcEdges[block][edge] = func;
 }
 text = null;
 var match;
 var gcThings = {};
 var gcPointers = {};
 text = snarf(gcTypesFile).split("\n");
 for (var line of text) {
     if (match = /^GCThing: (.*)/.exec(line))
         gcThings[match[1]] = true;
     if (match = /^GCPointer: (.*)/.exec(line))
         gcPointers[match[1]] = true;
 }
 text = null;
 function isUnrootedType(type)
 {
     if (type.Kind == "Pointer") {
         var target = type.Type;
         if (target.Kind == "CSU")
             return target.Name in gcThings;
         return false;
     }
     if (type.Kind == "CSU")
         return type.Name in gcPointers;
     return false;
 }
 function expressionUsesVariable(exp, variable)
 {
     if (exp.Kind == "Var" && sameVariable(exp.Variable, variable))
         return true;
     if (!("Exp" in exp))
         return false;
     for (var childExp of exp.Exp) {
         if (expressionUsesVariable(childExp, variable))
             return true;
     }
     return false;
 }
 function edgeUsesVariable(edge, variable)
 {
     if (ignoreEdgeUse(edge, variable))
         return false;
     switch (edge.Kind) {
     case "Assign":
         if (expressionUsesVariable(edge.Exp[0], variable))
             return true;
         return expressionUsesVariable(edge.Exp[1], variable);
     case "Assume":
         return expressionUsesVariable(edge.Exp[0], variable);
     case "Call":
         if (expressionUsesVariable(edge.Exp[0], variable))
             return true;
         if (1 in edge.Exp && expressionUsesVariable(edge.Exp[1], variable))
             return true;
         if ("PEdgeCallInstance" in edge) {
             if (expressionUsesVariable(edge.PEdgeCallInstance.Exp, variable))
                 return true;
         }
         if ("PEdgeCallArguments" in edge) {
             for (var exp of edge.PEdgeCallArguments.Exp) {
                 if (expressionUsesVariable(exp, variable))
                     return true;
             }
         }
         return false;
     case "Loop":
         return false;
     default:
         assert(false);
     }
 }
 function expressionIsVariableAddress(exp, variable)
 {
     while (exp.Kind == "Fld")
         exp = exp.Exp[0];
     return exp.Kind == "Var" && sameVariable(exp.Variable, variable);
 }
 function edgeTakesVariableAddress(edge, variable)
 {
     if (ignoreEdgeUse(edge, variable))
         return false;
     if (ignoreEdgeAddressTaken(edge))
         return false;
     switch (edge.Kind) {
     case "Assign":
         return expressionIsVariableAddress(edge.Exp[1], variable);
     case "Call":
         if ("PEdgeCallArguments" in edge) {
             for (var exp of edge.PEdgeCallArguments.Exp) {
                 if (expressionIsVariableAddress(exp, variable))
                     return true;
             }
         }
         return false;
     default:
         return false;
     }
 }
 function edgeKillsVariable(edge, variable)
 {
     // Direct assignments kill their lhs.
     if (edge.Kind == "Assign") {
         var lhs = edge.Exp[0];
         if (lhs.Kind == "Var" && sameVariable(lhs.Variable, variable))
             return true;
     }
     if (edge.Kind != "Call")
         return false;
     // Assignments of call results kill their lhs.
     if (1 in edge.Exp) {
         var lhs = edge.Exp[1];
         if (lhs.Kind == "Var" && sameVariable(lhs.Variable, variable))
             return true;
     }
     // Constructor calls kill their 'this' value.
     if ("PEdgeCallInstance" in edge) {
         do {
             var instance = edge.PEdgeCallInstance.Exp;
             // Kludge around incorrect dereference on some constructor calls.
             if (instance.Kind == "Drf")
                 instance = instance.Exp[0];
             if (instance.Kind != "Var" || !sameVariable(instance.Variable, variable))
                 break;
             var callee = edge.Exp[0];
             if (callee.Kind != "Var")
                 break;
             assert(callee.Variable.Kind == "Func");
             var calleeName = readable(callee.Variable.Name[0]);
             // Constructor calls include the text 'Name::Name(' or 'Name<...>::Name('.
             var openParen = calleeName.indexOf('(');
             if (openParen < 0)
                 break;
             calleeName = calleeName.substring(0, openParen);
             var lastColon = calleeName.lastIndexOf('::');
             if (lastColon < 0)
                 break;
             var constructorName = calleeName.substr(lastColon + 2);
             calleeName = calleeName.substr(0, lastColon);
             var lastTemplateOpen = calleeName.lastIndexOf('<');
             if (lastTemplateOpen >= 0)
                 calleeName = calleeName.substr(0, lastTemplateOpen);
             if (calleeName.endsWith(constructorName))
                 return true;
         } while (false);
     }
     return false;
 }
 function edgeCanGC(edge)
 {
     if (edge.Kind != "Call")
         return false;
     var callee = edge.Exp[0];
     if (callee.Kind == "Var") {
         var variable = callee.Variable;
         assert(variable.Kind == "Func");
         var callee = mangled(variable.Name[0]);
         if (callee in gcFunctions)
             return "'" + variable.Name[0] + "'";
         return null;
     }
     assert(callee.Kind == "Drf");
     if (callee.Exp[0].Kind == "Fld") {
         var field = callee.Exp[0].Field;
         var csuName = field.FieldCSU.Type.Name;
         var fullFieldName = csuName + "." + field.Name[0];
         if (fieldCallCannotGC(csuName, fullFieldName))
             return null;
         return (fullFieldName in suppressedFunctions) ? null : fullFieldName;
     }
     assert(callee.Exp[0].Kind == "Var");
     var varName = callee.Exp[0].Variable.Name[0];
     return indirectCallCannotGC(functionName, varName) ? null : "*" + varName;
 }
 function variableUseFollowsGC(suppressed, variable, worklist)
 {
     // Scan through all edges following an unrooted variable use, using an
     // explicit worklist. A worklist contains a following edge together with a
     // description of where one of its predecessors GC'd (if any).
     while (worklist.length) {
         var entry = worklist.pop();
         var body = entry.body, ppoint = entry.ppoint;
         if (body.seen) {
             if (ppoint in body.seen) {
                 var seenEntry = body.seen[ppoint];
                 if (!entry.gcInfo || seenEntry.gcInfo)
                     continue;
             }
         } else {
             body.seen = [];
         }
         body.seen[ppoint] = {body:body, gcInfo:entry.gcInfo};
         if (ppoint == body.Index[0]) {
             if (body.BlockId.Kind == "Loop") {
                 // propagate to parents that enter the loop body.
                 if ("BlockPPoint" in body) {
                     for (var parent of body.BlockPPoint) {
                         var found = false;
                         for (var xbody of functionBodies) {
                             if (sameBlockId(xbody.BlockId, parent.BlockId)) {
                                 assert(!found);
                                 found = true;
                                 worklist.push({body:xbody, ppoint:parent.Index,
                                                gcInfo:entry.gcInfo, why:entry});
                             }
                         }
                         assert(found);
                     }
                 }
             } else if (variable.Kind == "Arg" && entry.gcInfo) {
                 return {gcInfo:entry.gcInfo, why:entry};
             }
         }
         var predecessors = getPredecessors(body);
         if (!(ppoint in predecessors))
             continue;
         for (var edge of predecessors[ppoint]) {
             var source = edge.Index[0];
             if (edgeKillsVariable(edge, variable)) {
                 if (entry.gcInfo)
                     return {gcInfo:entry.gcInfo, why:entry};
                 if (!body.minimumUse || source < body.minimumUse)
                     body.minimumUse = source;
                 continue;
             }
             var gcInfo = entry.gcInfo;
             if (!gcInfo && !(source in body.suppressed) && !suppressed) {
                 var gcName = edgeCanGC(edge, body);
                 if (gcName)
                     gcInfo = {name:gcName, body:body, ppoint:source};
             }
             if (edgeUsesVariable(edge, variable)) {
                 if (gcInfo)
                     return {gcInfo:gcInfo, why:entry};
                 if (!body.minimumUse || source < body.minimumUse)
                     body.minimumUse = source;
             }
             if (edge.Kind == "Loop") {
                 // propagate to exit points of the loop body, in addition to the
                 // predecessor of the loop edge itself.
                 var found = false;
                 for (var xbody of functionBodies) {
                     if (sameBlockId(xbody.BlockId, edge.BlockId)) {
                         assert(!found);
                         found = true;
                         worklist.push({body:xbody, ppoint:xbody.Index[1],
                                        gcInfo:gcInfo, why:entry});
                     }
                 }
                 assert(found);
                 break;
             }
             worklist.push({body:body, ppoint:source, gcInfo:gcInfo, why:entry});
         }
     }
     return null;
 }
 function variableLiveAcrossGC(suppressed, variable)
 {
     // A variable is live across a GC if (1) it is used by an edge, and (2) it
     // is used after a GC in a successor edge.
     for (var body of functionBodies) {
         body.seen = null;
         body.minimumUse = 0;
     }
     for (var body of functionBodies) {
         if (!("PEdge" in body))
             continue;
         for (var edge of body.PEdge) {
             if (edgeUsesVariable(edge, variable) && !edgeKillsVariable(edge, variable)) {
                 var worklist = [{body:body, ppoint:edge.Index[0], gcInfo:null, why:null}];
                 var call = variableUseFollowsGC(suppressed, variable, worklist);
                 if (call)
                     return call;
             }
         }
     }
     return null;
 }
 // An unrooted variable has its address stored in another variable via
 // assignment, or passed into a function that can GC. If the address is
 // assigned into some other variable, we can't track it to see if it is held
 // live across a GC. If it is passed into a function that can GC, then it's
 // sort of like a Handle to an unrooted location, and the callee could GC
 // before overwriting it or rooting it.
 function unsafeVariableAddressTaken(suppressed, variable)
 {
     for (var body of functionBodies) {
         if (!("PEdge" in body))
             continue;
         for (var edge of body.PEdge) {
             if (edgeTakesVariableAddress(edge, variable)) {
                 if (edge.Kind == "Assign" || (!suppressed && edgeCanGC(edge)))
                     return {body:body, ppoint:edge.Index[0]};
             }
         }
     }
     return null;
 }
 function computePrintedLines(functionName)
 {
     assert(!system("xdbfind src_body.xdb '" + functionName + "' > " + tmpfile));
     var lines = snarf(tmpfile).split('\n');
     for (var body of functionBodies)
         body.lines = [];
     // Distribute lines of output to the block they originate from.
     var currentBody = null;
     for (var i = 0; i < lines.length; i++) {
         var line = lines[i];
         if (/^block:/.test(line)) {
             if (match = /:(loop#[\d#]+)/.exec(line)) {
                 var loop = match[1];
                 var found = false;
                 for (var body of functionBodies) {
                     if (body.BlockId.Kind == "Loop" && body.BlockId.Loop == loop) {
                         assert(!found);
                         found = true;
                         currentBody = body;
                     }
                 }
                 assert(found);
             } else {
                 for (var body of functionBodies) {
                     if (body.BlockId.Kind == "Function")
                         currentBody = body;
                 }
             }
         }
         if (currentBody)
             currentBody.lines.push(line);
     }
 }
 function findLocation(body, ppoint)
 {
     var location = body.PPoint[ppoint - 1].Location;
     var text = location.CacheString + ":" + location.Line;
     if (text.indexOf(sourceRoot) == 0)
         return text.substring(sourceRoot.length);
     return text;
 }
 function locationLine(text)
 {
     if (match = /:(\d+)$/.exec(text))
         return match[1];
     return 0;
 }
 function printEntryTrace(functionName, entry)
 {
     if (!functionBodies[0].lines)
         computePrintedLines(functionName);
     while (entry) {
         var ppoint = entry.ppoint;
         var lineText = findLocation(entry.body, ppoint);
         var edgeText = null;
         if (entry.why && entry.why.body == entry.body) {
             // If the next point in the trace is in the same block, look for an edge between them.
             var next = entry.why.ppoint;
             for (var line of entry.body.lines) {
                 if (match = /\((\d+),(\d+),/.exec(line)) {
                     if (match[1] == ppoint && match[2] == next)
                         edgeText = line; // May be multiple
                 }
             }
             assert(edgeText);
         } else {
             // Look for any outgoing edge from the chosen point.
             for (var line of entry.body.lines) {
                 if (match = /\((\d+),/.exec(line)) {
                     if (match[1] == ppoint) {
                         edgeText = line;
                         break;
                     }
                 }
             }
         }
         print("    " + lineText + (edgeText ? ": " + edgeText : ""));
         entry = entry.why;
     }
 }
 function isRootedType(type)
 {
     return type.Kind == "CSU" && isRootedTypeName(type.Name);
 }
 function typeDesc(type)
 {
     if (type.Kind == "CSU") {
         return type.Name;
     } else if ('Type' in type) {
         var inner = typeDesc(type.Type);
         if (type.Kind == 'Pointer')
             return inner + '*';
         else if (type.Kind == 'Array')
             return inner + '[]';
         else
             return inner + '?';
     } else {
         return '???';
     }
 }
 function processBodies(functionName)
 {
     if (!("DefineVariable" in functionBodies[0]))
         return;
     var suppressed = (mangled(functionName) in suppressedFunctions);
     for (var variable of functionBodies[0].DefineVariable) {
         if (variable.Variable.Kind == "Return")
             continue;
         var name;
         if (variable.Variable.Kind == "This")
             name = "this";
         else
             name = variable.Variable.Name[0];
         if (isRootedType(variable.Type)) {
             if (!variableLiveAcrossGC(suppressed, variable.Variable)) {
                 // The earliest use of the variable should be its constructor.
                 var lineText;
                 for (var body of functionBodies) {
                     if (body.minimumUse) {
                         var text = findLocation(body, body.minimumUse);
                         if (!lineText || locationLine(lineText) > locationLine(text))
                             lineText = text;
                     }
                 }
                 print("\nFunction '" + functionName + "'" +
                       " has unnecessary root '" + name + "' at " + lineText);
             }
         } else if (isUnrootedType(variable.Type)) {
             var result = variableLiveAcrossGC(suppressed, variable.Variable);
             if (result) {
                 var lineText = findLocation(result.gcInfo.body, result.gcInfo.ppoint);
                 print("\nFunction '" + functionName + "'" +
                       " has unrooted '" + name + "'" +
                       " of type '" + typeDesc(variable.Type) + "'" +
                       " live across GC call " + result.gcInfo.name +
                       " at " + lineText);
                 printEntryTrace(functionName, result.why);
             }
             result = unsafeVariableAddressTaken(suppressed, variable.Variable);
             if (result) {
                 var lineText = findLocation(result.body, result.ppoint);
                 print("\nFunction '" + functionName + "'" +
                       " takes unsafe address of unrooted '" + name + "'" +
                       " at " + lineText);
                 printEntryTrace(functionName, {body:result.body, ppoint:result.ppoint});
             }
         }
     }
 }
 if (batch == 1)
     print("Time: " + new Date);
 var xdb = xdbLibrary();
 xdb.open("src_body.xdb");
 var minStream = xdb.min_data_stream()|0;
 var maxStream = xdb.max_data_stream()|0;
 var N = (maxStream - minStream) + 1;
 var each = Math.floor(N/numBatches);
 var start = minStream + each * (batch - 1);
 var end = Math.min(minStream + each * batch - 1, maxStream);
 for (var nameIndex = start; nameIndex <= end; nameIndex++) {
     var name = xdb.read_key(nameIndex);
     var functionName = name.readString();
     var data = xdb.read_entry(name);
     xdb.free_string(name);
     var json = data.readString();
     xdb.free_string(data);
     functionBodies = JSON.parse(json);
     for (var body of functionBodies)
         body.suppressed = [];
     for (var body of functionBodies) {
         for (var [pbody, id] of allRAIIGuardedCallPoints(body, isSuppressConstructor))
             pbody.suppressed[id] = true;
     }
     processBodies(functionName);
 }