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comparison: js/public/ProfilingStack.h
js/public/ProfilingStack.h
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| 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- | |
| 2 * vim: set ts=8 sts=4 et sw=4 tw=99: | |
| 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 js_ProfilingStack_h | |
| 8 #define js_ProfilingStack_h | |
| 9 | |
| 10 #include "mozilla/NullPtr.h" | |
| 11 | |
| 12 #include "jsbytecode.h" | |
| 13 #include "jstypes.h" | |
| 14 | |
| 15 #include "js/Utility.h" | |
| 16 | |
| 17 struct JSRuntime; | |
| 18 | |
| 19 namespace js { | |
| 20 | |
| 21 // A call stack can be specified to the JS engine such that all JS entry/exits | |
| 22 // to functions push/pop an entry to/from the specified stack. | |
| 23 // | |
| 24 // For more detailed information, see vm/SPSProfiler.h. | |
| 25 // | |
| 26 class ProfileEntry | |
| 27 { | |
| 28 // All fields are marked volatile to prevent the compiler from re-ordering | |
| 29 // instructions. Namely this sequence: | |
| 30 // | |
| 31 // entry[size] = ...; | |
| 32 // size++; | |
| 33 // | |
| 34 // If the size modification were somehow reordered before the stores, then | |
| 35 // if a sample were taken it would be examining bogus information. | |
| 36 // | |
| 37 // A ProfileEntry represents both a C++ profile entry and a JS one. Both use | |
| 38 // the string as a description, but JS uses the sp as nullptr or (void*)1 to | |
| 39 // indicate that it is a JS entry. The script_ is then only ever examined for | |
| 40 // a JS entry, and the idx is used by both, but with different meanings. | |
| 41 // | |
| 42 const char * volatile string; // Descriptive string of this entry | |
| 43 void * volatile sp; // Relevant stack pointer for the entry, | |
| 44 // less than or equal to SCRIPT_OPT_STACKPOINTER for js | |
| 45 // script entries, greater for non-js entries. | |
| 46 JSScript * volatile script_; // if js(), non-null script which is running - low bit | |
| 47 // indicates if script is optimized or not. | |
| 48 int32_t volatile idx; // if js(), idx of pc, otherwise line number | |
| 49 | |
| 50 public: | |
| 51 static const uintptr_t SCRIPT_OPT_STACKPOINTER = 0x1; | |
| 52 | |
| 53 // All of these methods are marked with the 'volatile' keyword because SPS's | |
| 54 // representation of the stack is stored such that all ProfileEntry | |
| 55 // instances are volatile. These methods would not be available unless they | |
| 56 // were marked as volatile as well. | |
| 57 | |
| 58 bool js() const volatile { | |
| 59 MOZ_ASSERT_IF(uintptr_t(sp) <= SCRIPT_OPT_STACKPOINTER, script_ != nullptr); | |
| 60 return uintptr_t(sp) <= SCRIPT_OPT_STACKPOINTER; | |
| 61 } | |
| 62 | |
| 63 uint32_t line() const volatile { MOZ_ASSERT(!js()); return idx; } | |
| 64 JSScript *script() const volatile { MOZ_ASSERT(js()); return script_; } | |
| 65 bool scriptIsOptimized() const volatile { | |
| 66 MOZ_ASSERT(js()); | |
| 67 return uintptr_t(sp) <= SCRIPT_OPT_STACKPOINTER; | |
| 68 } | |
| 69 void *stackAddress() const volatile { | |
| 70 if (js()) | |
| 71 return nullptr; | |
| 72 return sp; | |
| 73 } | |
| 74 const char *label() const volatile { return string; } | |
| 75 | |
| 76 void setLine(uint32_t aLine) volatile { MOZ_ASSERT(!js()); idx = aLine; } | |
| 77 void setLabel(const char *aString) volatile { string = aString; } | |
| 78 void setStackAddress(void *aSp) volatile { sp = aSp; } | |
| 79 void setScript(JSScript *aScript) volatile { script_ = aScript; } | |
| 80 | |
| 81 // We can't know the layout of JSScript, so look in vm/SPSProfiler.cpp. | |
| 82 JS_FRIEND_API(jsbytecode *) pc() const volatile; | |
| 83 JS_FRIEND_API(void) setPC(jsbytecode *pc) volatile; | |
| 84 | |
| 85 static size_t offsetOfString() { return offsetof(ProfileEntry, string); } | |
| 86 static size_t offsetOfStackAddress() { return offsetof(ProfileEntry, sp); } | |
| 87 static size_t offsetOfPCIdx() { return offsetof(ProfileEntry, idx); } | |
| 88 static size_t offsetOfScript() { return offsetof(ProfileEntry, script_); } | |
| 89 | |
| 90 // The index used in the entry can either be a line number or the offset of | |
| 91 // a pc into a script's code. To signify a nullptr pc, use a -1 index. This | |
| 92 // is checked against in pc() and setPC() to set/get the right pc. | |
| 93 static const int32_t NullPCIndex = -1; | |
| 94 | |
| 95 // This bit is added to the stack address to indicate that copying the | |
| 96 // frame label is not necessary when taking a sample of the pseudostack. | |
| 97 static const uintptr_t NoCopyBit = 1; | |
| 98 }; | |
| 99 | |
| 100 JS_FRIEND_API(void) | |
| 101 SetRuntimeProfilingStack(JSRuntime *rt, ProfileEntry *stack, uint32_t *size, | |
| 102 uint32_t max); | |
| 103 | |
| 104 JS_FRIEND_API(void) | |
| 105 EnableRuntimeProfilingStack(JSRuntime *rt, bool enabled); | |
| 106 | |
| 107 JS_FRIEND_API(void) | |
| 108 RegisterRuntimeProfilingEventMarker(JSRuntime *rt, void (*fn)(const char *)); | |
| 109 | |
| 110 JS_FRIEND_API(jsbytecode*) | |
| 111 ProfilingGetPC(JSRuntime *rt, JSScript *script, void *ip); | |
| 112 | |
| 113 } // namespace js | |
| 114 | |
| 115 #endif /* js_ProfilingStack_h */ |
