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

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

js/src/devtools/rootAnalysis/loadCallgraph.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');
 // Functions come out of sixgill in the form "mangled|readable". The mangled
 // name is Truth. One mangled name might correspond to multiple readable names,
 // for multiple reasons, including (1) sixgill/gcc doesn't always qualify types
 // the same way or de-typedef the same amount; (2) sixgill's output treats
 // references and pointers the same, and so doesn't distinguish them, but C++
 // treats them as separate for overloading and linking; (3) (identical)
 // destructors sometimes have an int32 parameter, sometimes not.
 //
 // The readable names are useful because they're far more meaningful to the
 // user, and are what should show up in reports and questions to mrgiggles. At
 // least in most cases, it's fine to have the extra mangled name tacked onto
 // the beginning for these.
 //
 // The strategy used is to separate out the pieces whenever they are read in,
 // create a table mapping mangled names to (one of the) readable names, and
 // use the mangled names in all computation.
 //
 // Note that callgraph.txt uses a compressed representation -- each name is
 // mapped to an integer, and those integers are what is recorded in the edges.
 // But the integers depend on the full name, whereas the true edge should only
 // consider the mangled name. And some of the names encoded in callgraph.txt
 // are FieldCalls, not just function names.
 var readableNames = {}; // map from mangled name => list of readable names
 var mangledName = {}; // map from demangled names => mangled names. Could be eliminated.
 var calleeGraph = {}; // map from mangled => list of tuples of {'callee':mangled, 'suppressed':bool}
 var callerGraph = {}; // map from mangled => list of tuples of {'caller':mangled, 'suppressed':bool}
 var gcFunctions = {}; // map from mangled callee => reason
 var suppressedFunctions = {}; // set of mangled names (map from mangled name => true)
 var gcEdges = {};
 function addGCFunction(caller, reason)
 {
     if (caller in suppressedFunctions)
         return false;
     if (ignoreGCFunction(caller))
         return false;
     if (!(caller in gcFunctions)) {
         gcFunctions[caller] = reason;
         return true;
     }
     return false;
 }
 function addCallEdge(caller, callee, suppressed)
 {
     if (!(caller in calleeGraph))
         calleeGraph[caller] = [];
     calleeGraph[caller].push({callee:callee, suppressed:suppressed});
     if (!(callee in callerGraph))
         callerGraph[callee] = [];
     callerGraph[callee].push({caller:caller, suppressed:suppressed});
 }
 // Map from identifier to full "mangled|readable" name. Or sometimes to a
 // Class.Field name.
 var functionNames = [""];
 // Map from identifier to mangled name (or to a Class.Field)
 var idToMangled = [""];
 function loadCallgraph(file)
 {
     var suppressedFieldCalls = {};
     var resolvedFunctions = {};
     var textLines = snarf(file).split('\n');
     for (var line of textLines) {
         var match;
         if (match = line.charAt(0) == "#" && /^\#(\d+) (.*)/.exec(line)) {
             assert(functionNames.length == match[1]);
             functionNames.push(match[2]);
             var [ mangled, readable ] = splitFunction(match[2]);
             if (mangled in readableNames)
                 readableNames[mangled].push(readable);
             else
                 readableNames[mangled] = [ readable ];
             mangledName[readable] = mangled;
             idToMangled.push(mangled);
             continue;
         }
         var suppressed = false;
         if (line.indexOf("SUPPRESS_GC") != -1) {
             match = /^(..)SUPPRESS_GC (.*)/.exec(line);
             line = match[1] + match[2];
             suppressed = true;
         }
         var tag = line.charAt(0);
         if (match = tag == 'I' && /^I (\d+) VARIABLE ([^\,]*)/.exec(line)) {
             var mangledCaller = idToMangled[match[1]];
             var name = match[2];
             if (!indirectCallCannotGC(functionNames[match[1]], name) && !suppressed)
                 addGCFunction(mangledCaller, "IndirectCall: " + name);
         } else if (match = tag == 'F' && /^F (\d+) CLASS (.*?) FIELD (.*)/.exec(line)) {
             var caller = idToMangled[match[1]];
             var csu = match[2];
             var fullfield = csu + "." + match[3];
             if (suppressed)
                 suppressedFieldCalls[fullfield] = true;
             else if (!fieldCallCannotGC(csu, fullfield))
                 addGCFunction(caller, "FieldCall: " + fullfield);
         } else if (match = tag == 'D' && /^D (\d+) (\d+)/.exec(line)) {
             var caller = idToMangled[match[1]];
             var callee = idToMangled[match[2]];
             addCallEdge(caller, callee, suppressed);
         } else if (match = tag == 'R' && /^R (\d+) (\d+)/.exec(line)) {
             var callerField = idToMangled[match[1]];
             var callee = idToMangled[match[2]];
             addCallEdge(callerField, callee, false);
             resolvedFunctions[callerField] = true;
         }
     }
     // Initialize suppressedFunctions to the set of all functions, and the
     // worklist to all toplevel callers.
     var worklist = [];
     for (var callee in callerGraph)
         suppressedFunctions[callee] = true;
     for (var caller in calleeGraph) {
         if (!(caller in callerGraph)) {
             suppressedFunctions[caller] = true;
             worklist.push(caller);
         }
     }
     // Find all functions reachable via an unsuppressed call chain, and remove
     // them from the suppressedFunctions set. Everything remaining is only
     // reachable when GC is suppressed.
     var top = worklist.length;
     while (top > 0) {
         name = worklist[--top];
         if (!(name in suppressedFunctions))
             continue;
         delete suppressedFunctions[name];
         if (!(name in calleeGraph))
             continue;
         for (var entry of calleeGraph[name]) {
             if (!entry.suppressed)
                 worklist[top++] = entry.callee;
         }
     }
     // Such functions are known to not GC.
     for (var name in gcFunctions) {
         if (name in suppressedFunctions)
             delete gcFunctions[name];
     }
     for (var name in suppressedFieldCalls) {
         suppressedFunctions[name] = true;
     }
     for (var gcName of [ 'jsgc.cpp:void Collect(JSRuntime*, uint8, int64, uint32, uint32)',
                          'void js::MinorGC(JSRuntime*, uint32)' ])
     {
         assert(gcName in mangledName);
         addGCFunction(mangledName[gcName], "GC");
     }
     // Initialize the worklist to all known gcFunctions.
     var worklist = [];
     for (var name in gcFunctions)
         worklist.push(name);
     // Recursively find all callers and add them to the set of gcFunctions.
     while (worklist.length) {
         name = worklist.shift();
         assert(name in gcFunctions);
         if (!(name in callerGraph))
             continue;
         for (var entry of callerGraph[name]) {
             if (!entry.suppressed && addGCFunction(entry.caller, name))
                 worklist.push(entry.caller);
         }
     }
     // Any field call that has been resolved to all possible callees can be
     // trusted to not GC if all of those callees are known to not GC.
     for (var name in resolvedFunctions) {
         if (!(name in gcFunctions))
             suppressedFunctions[name] = true;
     }
 }