1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 * vim: set ts=8 sts=2 et sw=2 tw=80:
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #ifndef vm_Probes_h
8 #define vm_Probes_h
9
10 #ifdef INCLUDE_MOZILLA_DTRACE
11 # include "javascript-trace.h"
12 #endif
13
14 #include "vm/Stack.h"
15
16 namespace js {
17
18 namespace probes {
19
20 /*
21 * Static probes
22 *
23 * The probe points defined in this file are scattered around the SpiderMonkey
24 * source tree. The presence of probes::SomeEvent() means that someEvent is
25 * about to happen or has happened. To the extent possible, probes should be
26 * inserted in all paths associated with a given event, regardless of the
27 * active runmode (interpreter/traceJIT/methodJIT/ionJIT).
28 *
29 * When a probe fires, it is handled by any probe handling backends that have
30 * been compiled in. By default, most probes do nothing or at least do nothing
31 * expensive, so the presence of the probe should have negligible effect on
32 * running time. (Probes in slow paths may do something by default, as long as
33 * there is no noticeable slowdown.)
34 *
35 * For some probes, the mere existence of the probe is too expensive even if it
36 * does nothing when called. For example, just having consistent information
37 * available for a function call entry/exit probe causes the JITs to
38 * de-optimize function calls. In those cases, the JITs may query at compile
39 * time whether a probe is desired, and omit the probe invocation if not. If a
40 * probe is runtime-disabled at compilation time, it is not guaranteed to fire
41 * within a compiled function if it is later enabled.
42 *
43 * Not all backends handle all of the probes listed here.
44 */
45
46 /*
47 * Internal use only: remember whether "profiling", whatever that means, is
48 * currently active. Used for state management.
49 */
50 extern bool ProfilingActive;
51
52 extern const char nullName[];
53 extern const char anonymousName[];
54
55 /*
56 * Test whether we are tracking JS function call enter/exit. The JITs use this
57 * to decide whether they can optimize in a way that would prevent probes from
58 * firing.
59 */
60 bool CallTrackingActive(JSContext*);
61
62 /* Entering a JS function */
63 bool EnterScript(JSContext*, JSScript*, JSFunction*, InterpreterFrame*);
64
65 /* About to leave a JS function */
66 void ExitScript(JSContext*, JSScript*, JSFunction*, bool popProfilerFrame);
67
68 /* Executing a script */
69 bool StartExecution(JSScript* script);
70
71 /* Script has completed execution */
72 bool StopExecution(JSScript* script);
73
74 /*
75 * Object has been created. |obj| must exist (its class and size are read)
76 */
77 bool CreateObject(JSContext* cx, JSObject* obj);
78
79 /*
80 * Object is about to be finalized. |obj| must still exist (its class is
81 * read)
82 */
83 bool FinalizeObject(JSObject* obj);
84
85 /*
86 * Internal: DTrace-specific functions to be called during probes::EnterScript
87 * and probes::ExitScript. These will not be inlined, but the argument
88 * marshalling required for these probe points is expensive enough that it
89 * shouldn't really matter.
90 */
91 void DTraceEnterJSFun(JSContext* cx, JSFunction* fun, JSScript* script);
92 void DTraceExitJSFun(JSContext* cx, JSFunction* fun, JSScript* script);
93
94 } // namespace probes
95
96 #ifdef INCLUDE_MOZILLA_DTRACE
ObjectClassname(JSObject * obj)97 static const char* ObjectClassname(JSObject* obj) {
98 if (!obj) {
99 return "(null object)";
100 }
101 const JSClass* clasp = obj->getClass();
102 if (!clasp) {
103 return "(null)";
104 }
105 const char* class_name = clasp->name;
106 if (!class_name) {
107 return "(null class name)";
108 }
109 return class_name;
110 }
111 #endif
112
CreateObject(JSContext * cx,JSObject * obj)113 inline bool probes::CreateObject(JSContext* cx, JSObject* obj) {
114 bool ok = true;
115
116 #ifdef INCLUDE_MOZILLA_DTRACE
117 if (JAVASCRIPT_OBJECT_CREATE_ENABLED()) {
118 JAVASCRIPT_OBJECT_CREATE(ObjectClassname(obj), (uintptr_t)obj);
119 }
120 #endif
121
122 return ok;
123 }
124
FinalizeObject(JSObject * obj)125 inline bool probes::FinalizeObject(JSObject* obj) {
126 bool ok = true;
127
128 #ifdef INCLUDE_MOZILLA_DTRACE
129 if (JAVASCRIPT_OBJECT_FINALIZE_ENABLED()) {
130 const JSClass* clasp = obj->getClass();
131
132 /* the first arg is nullptr - reserved for future use (filename?) */
133 JAVASCRIPT_OBJECT_FINALIZE(nullptr, (char*)clasp->name, (uintptr_t)obj);
134 }
135 #endif
136
137 return ok;
138 }
139
140 } /* namespace js */
141
142 #endif /* vm_Probes_h */
143