The Tor Browser: js/src/builtin/Eval.cpp@6474c204b198 (annotated)

js/src/builtin/Eval.cpp@6474c204b198 (annotated)

js/src/builtin/Eval.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  * vim: set ts=8 sts=4 et sw=4 tw=99:
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "builtin/Eval.h"
 #include "mozilla/HashFunctions.h"
 #include "jscntxt.h"
 #include "jsonparser.h"
 #include "frontend/BytecodeCompiler.h"
 #include "vm/GlobalObject.h"
 #include "vm/Interpreter-inl.h"
 using namespace js;
 using mozilla::AddToHash;
 using mozilla::HashString;
 // We should be able to assert this for *any* fp->scopeChain().
 static void
 AssertInnerizedScopeChain(JSContext *cx, JSObject &scopeobj)
 {
 #ifdef DEBUG
     RootedObject obj(cx);
     for (obj = &scopeobj; obj; obj = obj->enclosingScope()) {
         if (JSObjectOp op = obj->getClass()->ext.innerObject) {
             JS_ASSERT(op(cx, obj) == obj);
         }
     }
 #endif
 }
 static bool
 IsEvalCacheCandidate(JSScript *script)
 {
     // Make sure there are no inner objects which might use the wrong parent
     // and/or call scope by reusing the previous eval's script. Skip the
     // script's first object, which entrains the eval's scope.
     return script->savedCallerFun() &&
            !script->hasSingletons() &&
            script->objects()->length == 1 &&
            !script->hasRegexps();
 }
 /* static */ HashNumber
 EvalCacheHashPolicy::hash(const EvalCacheLookup &l)
 {
     return AddToHash(HashString(l.str->chars(), l.str->length()),
                      l.callerScript.get(),
                      l.version,
                      l.pc);
 }
 /* static */ bool
 EvalCacheHashPolicy::match(const EvalCacheEntry &cacheEntry, const EvalCacheLookup &l)
 {
     JSScript *script = cacheEntry.script;
     JS_ASSERT(IsEvalCacheCandidate(script));
     // Get the source string passed for safekeeping in the atom map
     // by the prior eval to frontend::CompileScript.
     JSAtom *keyStr = script->atoms[0];
     return EqualStrings(keyStr, l.str) &&
            cacheEntry.callerScript == l.callerScript &&
            script->getVersion() == l.version &&
            cacheEntry.pc == l.pc;
 }
 // There are two things we want to do with each script executed in EvalKernel:
 //  1. notify OldDebugAPI about script creation/destruction
 //  2. add the script to the eval cache when EvalKernel is finished
 //
 // NB: Although the eval cache keeps a script alive wrt to the JS engine, from
 // an OldDebugAPI  user's perspective, we want each eval() to create and
 // destroy a script. This hides implementation details and means we don't have
 // to deal with calls to JS_GetScriptObject for scripts in the eval cache.
 class EvalScriptGuard
 {
     JSContext *cx_;
     Rooted<JSScript*> script_;
     /* These fields are only valid if lookup_.str is non-nullptr. */
     EvalCacheLookup lookup_;
     EvalCache::AddPtr p_;
     Rooted<JSLinearString*> lookupStr_;
   public:
     EvalScriptGuard(JSContext *cx)
         : cx_(cx), script_(cx), lookup_(cx), lookupStr_(cx) {}
     ~EvalScriptGuard() {
         if (script_) {
             CallDestroyScriptHook(cx_->runtime()->defaultFreeOp(), script_);
             script_->cacheForEval();
             EvalCacheEntry cacheEntry = {script_, lookup_.callerScript, lookup_.pc};
             lookup_.str = lookupStr_;
             if (lookup_.str && IsEvalCacheCandidate(script_))
                 cx_->runtime()->evalCache.relookupOrAdd(p_, lookup_, cacheEntry);
         }
     }
     void lookupInEvalCache(JSLinearString *str, JSScript *callerScript, jsbytecode *pc)
     {
         lookupStr_ = str;
         lookup_.str = str;
         lookup_.callerScript = callerScript;
         lookup_.version = cx_->findVersion();
         lookup_.pc = pc;
         p_ = cx_->runtime()->evalCache.lookupForAdd(lookup_);
         if (p_) {
             script_ = p_->script;
             cx_->runtime()->evalCache.remove(p_);
             CallNewScriptHook(cx_, script_, NullPtr());
             script_->uncacheForEval();
         }
     }
     void setNewScript(JSScript *script) {
         // JSScript::initFromEmitter has already called js_CallNewScriptHook.
         JS_ASSERT(!script_ && script);
         script_ = script;
         script_->setActiveEval();
     }
     bool foundScript() {
         return !!script_;
     }
     HandleScript script() {
         JS_ASSERT(script_);
         return script_;
     }
 };
 enum EvalJSONResult {
     EvalJSON_Failure,
     EvalJSON_Success,
     EvalJSON_NotJSON
 };
 static EvalJSONResult
 TryEvalJSON(JSContext *cx, JSScript *callerScript,
             ConstTwoByteChars chars, size_t length, MutableHandleValue rval)
 {
     // If the eval string starts with '(' or '[' and ends with ')' or ']', it may be JSON.
     // Try the JSON parser first because it's much faster.  If the eval string
     // isn't JSON, JSON parsing will probably fail quickly, so little time
     // will be lost.
     //
     // Don't use the JSON parser if the caller is strict mode code, because in
     // strict mode object literals must not have repeated properties, and the
     // JSON parser cheerfully (and correctly) accepts them.  If you're parsing
     // JSON with eval and using strict mode, you deserve to be slow.
     if (length > 2 &&
         ((chars[0] == '[' && chars[length - 1] == ']') ||
         (chars[0] == '(' && chars[length - 1] == ')')) &&
         (!callerScript || !callerScript->strict()))
     {
         // Remarkably, JavaScript syntax is not a superset of JSON syntax:
         // strings in JavaScript cannot contain the Unicode line and paragraph
         // terminator characters U+2028 and U+2029, but strings in JSON can.
         // Rather than force the JSON parser to handle this quirk when used by
         // eval, we simply don't use the JSON parser when either character
         // appears in the provided string.  See bug 657367.
         for (const jschar *cp = &chars[1], *end = &chars[length - 2]; ; cp++) {
             if (*cp == 0x2028 || *cp == 0x2029)
                 break;
             if (cp == end) {
                 bool isArray = (chars[0] == '[');
                 JSONParser parser(cx, isArray ? chars : chars + 1U, isArray ? length : length - 2,
                                   JSONParser::NoError);
                 RootedValue tmp(cx);
                 if (!parser.parse(&tmp))
                     return EvalJSON_Failure;
                 if (tmp.isUndefined())
                     return EvalJSON_NotJSON;
                 rval.set(tmp);
                 return EvalJSON_Success;
             }
         }
     }
     return EvalJSON_NotJSON;
 }
 // Define subset of ExecuteType so that casting performs the injection.
 enum EvalType { DIRECT_EVAL = EXECUTE_DIRECT_EVAL, INDIRECT_EVAL = EXECUTE_INDIRECT_EVAL };
 // Common code implementing direct and indirect eval.
 //
 // Evaluate call.argv[2], if it is a string, in the context of the given calling
 // frame, with the provided scope chain, with the semantics of either a direct
 // or indirect eval (see ES5 10.4.2).  If this is an indirect eval, scopeobj
 // must be a global object.
 //
 // On success, store the completion value in call.rval and return true.
 static bool
 EvalKernel(JSContext *cx, const CallArgs &args, EvalType evalType, AbstractFramePtr caller,
            HandleObject scopeobj, jsbytecode *pc)
 {
     JS_ASSERT((evalType == INDIRECT_EVAL) == !caller);
     JS_ASSERT((evalType == INDIRECT_EVAL) == !pc);
     JS_ASSERT_IF(evalType == INDIRECT_EVAL, scopeobj->is<GlobalObject>());
     AssertInnerizedScopeChain(cx, *scopeobj);
     Rooted<GlobalObject*> scopeObjGlobal(cx, &scopeobj->global());
     if (!GlobalObject::isRuntimeCodeGenEnabled(cx, scopeObjGlobal)) {
         JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_CSP_BLOCKED_EVAL);
         return false;
     }
     // ES5 15.1.2.1 step 1.
     if (args.length() < 1) {
         args.rval().setUndefined();
         return true;
     }
     if (!args[0].isString()) {
         args.rval().set(args[0]);
         return true;
     }
     RootedString str(cx, args[0].toString());
     // ES5 15.1.2.1 steps 2-8.
     // Per ES5, indirect eval runs in the global scope. (eval is specified this
     // way so that the compiler can make assumptions about what bindings may or
     // may not exist in the current frame if it doesn't see 'eval'.)
     unsigned staticLevel;
     RootedValue thisv(cx);
     if (evalType == DIRECT_EVAL) {
         JS_ASSERT_IF(caller.isInterpreterFrame(), !caller.asInterpreterFrame()->runningInJit());
         staticLevel = caller.script()->staticLevel() + 1;
         // Direct calls to eval are supposed to see the caller's |this|. If we
         // haven't wrapped that yet, do so now, before we make a copy of it for
         // the eval code to use.
         if (!ComputeThis(cx, caller))
             return false;
         thisv = caller.thisValue();
     } else {
         JS_ASSERT(args.callee().global() == *scopeobj);
         staticLevel = 0;
         // Use the global as 'this', modulo outerization.
         JSObject *thisobj = JSObject::thisObject(cx, scopeobj);
         if (!thisobj)
             return false;
         thisv = ObjectValue(*thisobj);
     }
     Rooted<JSFlatString*> flatStr(cx, str->ensureFlat(cx));
     if (!flatStr)
         return false;
     size_t length = flatStr->length();
     ConstTwoByteChars chars(flatStr->chars(), length);
     RootedScript callerScript(cx, caller ? caller.script() : nullptr);
     EvalJSONResult ejr = TryEvalJSON(cx, callerScript, chars, length, args.rval());
     if (ejr != EvalJSON_NotJSON)
         return ejr == EvalJSON_Success;
     EvalScriptGuard esg(cx);
     if (evalType == DIRECT_EVAL && caller.isNonEvalFunctionFrame())
         esg.lookupInEvalCache(flatStr, callerScript, pc);
     if (!esg.foundScript()) {
         RootedScript maybeScript(cx);
         unsigned lineno;
         const char *filename;
         JSPrincipals *originPrincipals;
         uint32_t pcOffset;
         DescribeScriptedCallerForCompilation(cx, &maybeScript, &filename, &lineno, &pcOffset,
                                              &originPrincipals,
                                              evalType == DIRECT_EVAL
                                              ? CALLED_FROM_JSOP_EVAL
                                              : NOT_CALLED_FROM_JSOP_EVAL);
         const char *introducerFilename = filename;
         if (maybeScript && maybeScript->scriptSource()->introducerFilename())
             introducerFilename = maybeScript->scriptSource()->introducerFilename();
         CompileOptions options(cx);
         options.setFileAndLine(filename, 1)
                .setCompileAndGo(true)
                .setForEval(true)
                .setNoScriptRval(false)
                .setOriginPrincipals(originPrincipals)
                .setIntroductionInfo(introducerFilename, "eval", lineno, maybeScript, pcOffset);
         SourceBufferHolder srcBuf(chars.get(), length, SourceBufferHolder::NoOwnership);
         JSScript *compiled = frontend::CompileScript(cx, &cx->tempLifoAlloc(),
                                                      scopeobj, callerScript, options,
                                                      srcBuf, flatStr, staticLevel);
         if (!compiled)
             return false;
         esg.setNewScript(compiled);
     }
     return ExecuteKernel(cx, esg.script(), *scopeobj, thisv, ExecuteType(evalType),
                          NullFramePtr() /* evalInFrame */, args.rval().address());
 }
 bool
 js::DirectEvalStringFromIon(JSContext *cx,
                             HandleObject scopeobj, HandleScript callerScript,
                             HandleValue thisValue, HandleString str,
                             jsbytecode *pc, MutableHandleValue vp)
 {
     AssertInnerizedScopeChain(cx, *scopeobj);
     Rooted<GlobalObject*> scopeObjGlobal(cx, &scopeobj->global());
     if (!GlobalObject::isRuntimeCodeGenEnabled(cx, scopeObjGlobal)) {
         JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_CSP_BLOCKED_EVAL);
         return false;
     }
     // ES5 15.1.2.1 steps 2-8.
     unsigned staticLevel = callerScript->staticLevel() + 1;
     Rooted<JSFlatString*> flatStr(cx, str->ensureFlat(cx));
     if (!flatStr)
         return false;
     size_t length = flatStr->length();
     ConstTwoByteChars chars(flatStr->chars(), length);
     EvalJSONResult ejr = TryEvalJSON(cx, callerScript, chars, length, vp);
     if (ejr != EvalJSON_NotJSON)
         return ejr == EvalJSON_Success;
     EvalScriptGuard esg(cx);
     esg.lookupInEvalCache(flatStr, callerScript, pc);
     if (!esg.foundScript()) {
         RootedScript maybeScript(cx);
         const char *filename;
         unsigned lineno;
         JSPrincipals *originPrincipals;
         uint32_t pcOffset;
         DescribeScriptedCallerForCompilation(cx, &maybeScript, &filename, &lineno, &pcOffset,
                                               &originPrincipals, CALLED_FROM_JSOP_EVAL);
         const char *introducerFilename = filename;
         if (maybeScript && maybeScript->scriptSource()->introducerFilename())
             introducerFilename = maybeScript->scriptSource()->introducerFilename();
         CompileOptions options(cx);
         options.setFileAndLine(filename, 1)
                .setCompileAndGo(true)
                .setForEval(true)
                .setNoScriptRval(false)
                .setOriginPrincipals(originPrincipals)
                .setIntroductionInfo(introducerFilename, "eval", lineno, maybeScript, pcOffset);
         SourceBufferHolder srcBuf(chars.get(), length, SourceBufferHolder::NoOwnership);
         JSScript *compiled = frontend::CompileScript(cx, &cx->tempLifoAlloc(),
                                                      scopeobj, callerScript, options,
                                                      srcBuf, flatStr, staticLevel);
         if (!compiled)
             return false;
         esg.setNewScript(compiled);
     }
     // Primitive 'this' values should have been filtered out by Ion. If boxed,
     // the calling frame cannot be updated to store the new object.
     JS_ASSERT(thisValue.isObject() || thisValue.isUndefined() || thisValue.isNull());
     return ExecuteKernel(cx, esg.script(), *scopeobj, thisValue, ExecuteType(DIRECT_EVAL),
                          NullFramePtr() /* evalInFrame */, vp.address());
 }
 bool
 js::DirectEvalValueFromIon(JSContext *cx,
                            HandleObject scopeobj, HandleScript callerScript,
                            HandleValue thisValue, HandleValue evalArg,
                            jsbytecode *pc, MutableHandleValue vp)
 {
     // Act as identity on non-strings per ES5 15.1.2.1 step 1.
     if (!evalArg.isString()) {
         vp.set(evalArg);
         return true;
     }
     RootedString string(cx, evalArg.toString());
     return DirectEvalStringFromIon(cx, scopeobj, callerScript, thisValue, string, pc, vp);
 }
 bool
 js::IndirectEval(JSContext *cx, unsigned argc, Value *vp)
 {
     CallArgs args = CallArgsFromVp(argc, vp);
     Rooted<GlobalObject*> global(cx, &args.callee().global());
     return EvalKernel(cx, args, INDIRECT_EVAL, NullFramePtr(), global, nullptr);
 }
 bool
 js::DirectEval(JSContext *cx, const CallArgs &args)
 {
     // Direct eval can assume it was called from an interpreted or baseline frame.
     ScriptFrameIter iter(cx);
     AbstractFramePtr caller = iter.abstractFramePtr();
     JS_ASSERT(caller.scopeChain()->global().valueIsEval(args.calleev()));
     JS_ASSERT(JSOp(*iter.pc()) == JSOP_EVAL ||
               JSOp(*iter.pc()) == JSOP_SPREADEVAL);
     JS_ASSERT_IF(caller.isFunctionFrame(),
                  caller.compartment() == caller.callee()->compartment());
     RootedObject scopeChain(cx, caller.scopeChain());
     return EvalKernel(cx, args, DIRECT_EVAL, caller, scopeChain, iter.pc());
 }
 bool
 js::IsAnyBuiltinEval(JSFunction *fun)
 {
     return fun->maybeNative() == IndirectEval;
 }

The Tor Browser / annotate

js/src/builtin/Eval.cpp@6474c204b198 (annotated)

js/src/builtin/Eval.cpp