/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- * vim: set ts=8 sts=2 et sw=2 tw=80: * 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/. */ #ifndef debugger_DebugAPI_h #define debugger_DebugAPI_h #include "vm/GlobalObject.h" #include "vm/Interpreter.h" #include "vm/JSContext.h" #include "vm/Realm.h" namespace js { // This file contains the API which SpiderMonkey should use to interact with any // active Debuggers. class AbstractGeneratorObject; class PromiseObject; /** * DebugAPI::onNativeCall allows the debugger to call callbacks just before * some native functions are to be executed. It also allows the hooks * themselves to affect the result of the call. This enum represents the * various affects that DebugAPI::onNativeCall may perform. */ enum class NativeResumeMode { /** * If the debugger hook did not return a value to manipulate the result of * the native call, execution can continue unchanged. * * Continue indicates that the native function should execute normally. */ Continue, /** * If the debugger hook returned an explicit return value that is meant to * take the place of the native call's result, execution of the native * function needs to be skipped in favor of the explicit result. * * Override indicates that the native function should be skipped and that * the debugger has already stored the return value into the CallArgs. */ Override, /** * If the debugger hook returns an explicit termination or an explicit * thrown exception, execution of the native function needs to be skipped * in favor of handling the error condition. * * Abort indicates that the native function should be skipped and that * execution should be terminated. The debugger may or may not have set a * pending exception. */ Abort, }; class DebugScript; class DebuggerVector; class DebugAPI { public: friend class Debugger; /*** Methods for interaction with the GC. ***********************************/ /* * Trace (inferred) owning edges from stack frames to Debugger.Frames, as part * of root marking. * * Even if a Debugger.Frame for a live stack frame is entirely unreachable * from JS, if it has onStep or onPop hooks set, then collecting it would have * observable side effects - namely, the hooks would fail to run. The effect * is the same as if the stack frame held an owning edge to its * Debugger.Frame. * * Debugger.Frames must also be retained if the Debugger to which they belong * is reachable, even if they have no hooks set, but we handle that elsewhere; * this function is only concerned with the inferred roots from stack frames * to Debugger.Frames that have hooks set. */ static void traceFramesWithLiveHooks(JSTracer* tracer); /* * Trace (inferred) owning edges from generator objects to Debugger.Frames. * * Even if a Debugger.Frame for a live suspended generator object is entirely * unreachable from JS, if it has onStep or onPop hooks set, then collecting * it would have observable side effects - namely, the hooks would fail to run * if the generator is resumed. The effect is the same as if the generator * object held an owning edge to its Debugger.Frame. */ static inline void traceGeneratorFrame(JSTracer* tracer, AbstractGeneratorObject* generator); // Trace cross compartment edges in all debuggers relevant to the current GC. static void traceCrossCompartmentEdges(JSTracer* tracer); // Trace all debugger-owned GC things unconditionally, during a moving GC. static void traceAllForMovingGC(JSTracer* trc); // Trace debugging information for a JSScript. static void traceDebugScript(JSTracer* trc, JSScript* script); static void traceFromRealm(JSTracer* trc, Realm* realm); // The garbage collector calls this after everything has been marked, but // before anything has been finalized. We use this to clear Debugger / // debuggee edges at a point where the parties concerned are all still // initialized. static void sweepAll(JSFreeOp* fop); // Add sweep group edges due to the presence of any debuggers. static MOZ_MUST_USE bool findSweepGroupEdges(JSRuntime* rt); // Destroy the debugging information associated with a script. static void destroyDebugScript(JSFreeOp* fop, JSScript* script); // Validate the debugging information in a script after a moving GC> #ifdef JSGC_HASH_TABLE_CHECKS static void checkDebugScriptAfterMovingGC(DebugScript* ds); #endif #ifdef DEBUG static bool edgeIsInDebuggerWeakmap(JSRuntime* rt, JSObject* src, JS::GCCellPtr dst); #endif /*** Methods for querying script breakpoint state. **************************/ // Query information about whether any debuggers are observing a script. static inline bool stepModeEnabled(JSScript* script); static inline bool hasBreakpointsAt(JSScript* script, jsbytecode* pc); static inline bool hasAnyBreakpointsOrStepMode(JSScript* script); /*** Methods for interacting with the JITs. *********************************/ // Update Debugger frames when an interpreter frame is replaced with a // baseline frame. static MOZ_MUST_USE bool handleBaselineOsr(JSContext* cx, InterpreterFrame* from, jit::BaselineFrame* to); // Update Debugger frames when an Ion frame bails out and is replaced with a // baseline frame. static MOZ_MUST_USE bool handleIonBailout(JSContext* cx, jit::RematerializedFrame* from, jit::BaselineFrame* to); // Detach any Debugger frames from an Ion frame after an error occurred while // it bailed out. static void handleUnrecoverableIonBailoutError( JSContext* cx, jit::RematerializedFrame* frame); // When doing on-stack-replacement of a debuggee interpreter frame with a // baseline frame, ensure that the resulting frame can be observed by the // debugger. static MOZ_MUST_USE bool ensureExecutionObservabilityOfOsrFrame( JSContext* cx, AbstractFramePtr osrSourceFrame); // Describes a set of scripts or frames whose execution observability can // change due to debugger activity. class ExecutionObservableSet { public: using ZoneRange = HashSet::Range; virtual Zone* singleZone() const { return nullptr; } virtual JSScript* singleScriptForZoneInvalidation() const { return nullptr; } virtual const HashSet* zones() const { return nullptr; } virtual bool shouldRecompileOrInvalidate(JSScript* script) const = 0; virtual bool shouldMarkAsDebuggee(FrameIter& iter) const = 0; }; // This enum is converted to and compare with bool values; NotObserving // must be 0 and Observing must be 1. enum IsObserving { NotObserving = 0, Observing = 1 }; /*** Methods for calling installed debugger handlers. ***********************/ // Called when a new script becomes accessible to debuggers. static void onNewScript(JSContext* cx, HandleScript script); // Called when a new wasm instance becomes accessible to debuggers. static inline void onNewWasmInstance( JSContext* cx, Handle wasmInstance); /* * Announce to the debugger that the context has entered a new JavaScript * frame, |frame|. Call whatever hooks have been registered to observe new * frames. */ static inline MOZ_MUST_USE bool onEnterFrame(JSContext* cx, AbstractFramePtr frame); /* * Like onEnterFrame, but for resuming execution of a generator or async * function. `frame` is a new baseline or interpreter frame, but abstractly * it can be identified with a particular generator frame that was * suspended earlier. * * There is no separate user-visible Debugger.onResumeFrame hook; this * fires .onEnterFrame (again, since we're re-entering the frame). * * Unfortunately, the interpreter and the baseline JIT arrange for this to * be called in different ways. The interpreter calls it from JSOp::Resume, * immediately after pushing the resumed frame; the JIT calls it from * JSOp::AfterYield, just after the generator resumes. The difference * should not be user-visible. */ static inline MOZ_MUST_USE bool onResumeFrame(JSContext* cx, AbstractFramePtr frame); static inline NativeResumeMode onNativeCall(JSContext* cx, const CallArgs& args, CallReason reason); /* * Announce to the debugger a |debugger;| statement on has been * encountered on the youngest JS frame on |cx|. Call whatever hooks have * been registered to observe this. * * Note that this method is called for all |debugger;| statements, * regardless of the frame's debuggee-ness. */ static inline MOZ_MUST_USE bool onDebuggerStatement(JSContext* cx, AbstractFramePtr frame); /* * Announce to the debugger that an exception has been thrown and propagated * to |frame|. Call whatever hooks have been registered to observe this. */ static inline MOZ_MUST_USE bool onExceptionUnwind(JSContext* cx, AbstractFramePtr frame); /* * Announce to the debugger that the thread has exited a JavaScript frame, * |frame|. If |ok| is true, the frame is returning normally; if |ok| is * false, the frame is throwing an exception or terminating. * * Change cx's current exception and |frame|'s return value to reflect the * changes in behavior the hooks request, if any. Return the new error/success * value. * * This function may be called twice for the same outgoing frame; only the * first call has any effect. (Permitting double calls simplifies some * cases where an onPop handler's resumption value changes a return to a * throw, or vice versa: we can redirect to a complete copy of the * alternative path, containing its own call to onLeaveFrame.) */ static inline MOZ_MUST_USE bool onLeaveFrame(JSContext* cx, AbstractFramePtr frame, jsbytecode* pc, bool ok); // Call any breakpoint handlers for the current scripted location. static MOZ_MUST_USE bool onTrap(JSContext* cx); // Call any stepping handlers for the current scripted location. static MOZ_MUST_USE bool onSingleStep(JSContext* cx); // Notify any Debugger instances observing this promise's global that a new // promise was allocated. static inline void onNewPromise(JSContext* cx, Handle promise); // Notify any Debugger instances observing this promise's global that the // promise has settled (ie, it has either been fulfilled or rejected). Note // that this is *not* equivalent to the promise resolution (ie, the promise's // fate getting locked in) because you can resolve a promise with another // pending promise, in which case neither promise has settled yet. // // This should never be called on the same promise more than once, because a // promise can only make the transition from unsettled to settled once. static inline void onPromiseSettled(JSContext* cx, Handle promise); // Notify any Debugger instances that a new global object has been created. static inline void onNewGlobalObject(JSContext* cx, Handle global); /*** Methods for querying installed debugger handlers. **********************/ // Whether any debugger is observing execution in a global. static bool debuggerObservesAllExecution(GlobalObject* global); // Whether any debugger is observing JS execution coverage in a global. static bool debuggerObservesCoverage(GlobalObject* global); // Whether any Debugger is observing asm.js execution in a global. static bool debuggerObservesAsmJS(GlobalObject* global); /* * Return true if the given global is being observed by at least one * Debugger that is tracking allocations. */ static bool isObservedByDebuggerTrackingAllocations( const GlobalObject& debuggee); // If any debuggers are tracking allocations for a global, return the // probability that a given allocation should be tracked. Nothing otherwise. static mozilla::Maybe allocationSamplingProbability( GlobalObject* global); // Whether any debugger is observing exception unwinds in a realm. static bool hasExceptionUnwindHook(GlobalObject* global); // Whether any debugger is observing debugger statements in a realm. static bool hasDebuggerStatementHook(GlobalObject* global); /*** Assorted methods for interacting with the runtime. *********************/ // Checks if the current compartment is allowed to execute code. static inline MOZ_MUST_USE bool checkNoExecute(JSContext* cx, HandleScript script); /* * Announce to the debugger that a generator object has been created, * via JSOp::Generator. * * This does not fire user hooks, but it's needed for debugger bookkeeping. */ static inline MOZ_MUST_USE bool onNewGenerator( JSContext* cx, AbstractFramePtr frame, Handle genObj); // If necessary, record an object that was just allocated for any observing // debuggers. static inline MOZ_MUST_USE bool onLogAllocationSite(JSContext* cx, JSObject* obj, HandleSavedFrame frame, mozilla::TimeStamp when); // Announce to the debugger that a global object is being collected by the // specified major GC. static inline void notifyParticipatesInGC(GlobalObject* global, uint64_t majorGCNumber); /* * Get any instrumentation ID which has been associated with a script using * the specified debugger object. */ static bool getScriptInstrumentationId(JSContext* cx, HandleObject dbgObject, HandleScript script, MutableHandleValue rval); private: static bool stepModeEnabledSlow(JSScript* script); static bool hasBreakpointsAtSlow(JSScript* script, jsbytecode* pc); static void slowPathOnNewGlobalObject(JSContext* cx, Handle global); static void slowPathNotifyParticipatesInGC(uint64_t majorGCNumber, JS::Realm::DebuggerVector& dbgs); static MOZ_MUST_USE bool slowPathOnLogAllocationSite( JSContext* cx, HandleObject obj, HandleSavedFrame frame, mozilla::TimeStamp when, JS::Realm::DebuggerVector& dbgs); static MOZ_MUST_USE bool slowPathOnLeaveFrame(JSContext* cx, AbstractFramePtr frame, jsbytecode* pc, bool ok); static MOZ_MUST_USE bool slowPathOnNewGenerator( JSContext* cx, AbstractFramePtr frame, Handle genObj); static MOZ_MUST_USE bool slowPathCheckNoExecute(JSContext* cx, HandleScript script); static MOZ_MUST_USE bool slowPathOnEnterFrame(JSContext* cx, AbstractFramePtr frame); static MOZ_MUST_USE bool slowPathOnResumeFrame(JSContext* cx, AbstractFramePtr frame); static NativeResumeMode slowPathOnNativeCall(JSContext* cx, const CallArgs& args, CallReason reason); static MOZ_MUST_USE bool slowPathOnDebuggerStatement(JSContext* cx, AbstractFramePtr frame); static MOZ_MUST_USE bool slowPathOnExceptionUnwind(JSContext* cx, AbstractFramePtr frame); static void slowPathOnNewWasmInstance( JSContext* cx, Handle wasmInstance); static void slowPathOnNewPromise(JSContext* cx, Handle promise); static void slowPathOnPromiseSettled(JSContext* cx, Handle promise); static bool inFrameMaps(AbstractFramePtr frame); static void slowPathTraceGeneratorFrame(JSTracer* tracer, AbstractGeneratorObject* generator); }; // Suppresses all debuggee NX checks, i.e., allow all execution. Used to allow // certain whitelisted operations to execute code. // // WARNING // WARNING Do not use this unless you know what you are doing! // WARNING class AutoSuppressDebuggeeNoExecuteChecks { EnterDebuggeeNoExecute** stack_; EnterDebuggeeNoExecute* prev_; public: explicit AutoSuppressDebuggeeNoExecuteChecks(JSContext* cx) { stack_ = &cx->noExecuteDebuggerTop.ref(); prev_ = *stack_; *stack_ = nullptr; } ~AutoSuppressDebuggeeNoExecuteChecks() { MOZ_ASSERT(!*stack_); *stack_ = prev_; } }; } /* namespace js */ #endif /* debugger_DebugAPI_h */