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Diffstat (limited to 'memory/replace/dmd/DMD.cpp')
| -rw-r--r-- | memory/replace/dmd/DMD.cpp | 1884 |
1 files changed, 1884 insertions, 0 deletions
diff --git a/memory/replace/dmd/DMD.cpp b/memory/replace/dmd/DMD.cpp new file mode 100644 index 0000000000..54a154e60e --- /dev/null +++ b/memory/replace/dmd/DMD.cpp @@ -0,0 +1,1884 @@ +/* -*- 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/. */ + +#include <ctype.h> +#include <errno.h> +#include <limits.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#if !defined(MOZ_PROFILING) +# error "DMD requires MOZ_PROFILING" +#endif + +#ifdef XP_WIN +# include <windows.h> +# include <process.h> +#else +# include <pthread.h> +# include <sys/types.h> +# include <unistd.h> +#endif + +#ifdef ANDROID +# include <android/log.h> +#endif + +#include "nscore.h" + +#include "mozilla/Assertions.h" +#include "mozilla/FastBernoulliTrial.h" +#include "mozilla/HashFunctions.h" +#include "mozilla/HashTable.h" +#include "mozilla/IntegerPrintfMacros.h" +#include "mozilla/JSONWriter.h" +#include "mozilla/Likely.h" +#include "mozilla/MemoryReporting.h" +#include "mozilla/PodOperations.h" +#include "mozilla/StackWalk.h" +#include "mozilla/ThreadLocal.h" + +// CodeAddressService is defined entirely in the header, so this does not make +// DMD depend on XPCOM's object file. +#include "CodeAddressService.h" + +// replace_malloc.h needs to be included before replace_malloc_bridge.h, +// which DMD.h includes, so DMD.h needs to be included after replace_malloc.h. +#include "replace_malloc.h" +#include "DMD.h" + +namespace mozilla { +namespace dmd { + +class DMDBridge : public ReplaceMallocBridge { + virtual DMDFuncs* GetDMDFuncs() override; +}; + +static DMDBridge* gDMDBridge; +static DMDFuncs gDMDFuncs; + +DMDFuncs* DMDBridge::GetDMDFuncs() { return &gDMDFuncs; } + +MOZ_FORMAT_PRINTF(1, 2) +inline void StatusMsg(const char* aFmt, ...) { + va_list ap; + va_start(ap, aFmt); + gDMDFuncs.StatusMsg(aFmt, ap); + va_end(ap); +} + +//--------------------------------------------------------------------------- +// Utilities +//--------------------------------------------------------------------------- + +#ifndef DISALLOW_COPY_AND_ASSIGN +# define DISALLOW_COPY_AND_ASSIGN(T) \ + T(const T&); \ + void operator=(const T&) +#endif + +static malloc_table_t gMallocTable; + +// This provides infallible allocations (they abort on OOM). We use it for all +// of DMD's own allocations, which fall into the following three cases. +// +// - Direct allocations (the easy case). +// +// - Indirect allocations in mozilla::{Vector,HashSet,HashMap} -- this class +// serves as their AllocPolicy. +// +// - Other indirect allocations (e.g. MozStackWalk) -- see the comments on +// Thread::mBlockIntercepts and in replace_malloc for how these work. +// +// It would be nice if we could use the InfallibleAllocPolicy from mozalloc, +// but DMD cannot use mozalloc. +// +class InfallibleAllocPolicy { + static void ExitOnFailure(const void* aP); + + public: + template <typename T> + static T* maybe_pod_malloc(size_t aNumElems) { + if (aNumElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value) + return nullptr; + return (T*)gMallocTable.malloc(aNumElems * sizeof(T)); + } + + template <typename T> + static T* maybe_pod_calloc(size_t aNumElems) { + return (T*)gMallocTable.calloc(aNumElems, sizeof(T)); + } + + template <typename T> + static T* maybe_pod_realloc(T* aPtr, size_t aOldSize, size_t aNewSize) { + if (aNewSize & mozilla::tl::MulOverflowMask<sizeof(T)>::value) + return nullptr; + return (T*)gMallocTable.realloc(aPtr, aNewSize * sizeof(T)); + } + + static void* malloc_(size_t aSize) { + void* p = gMallocTable.malloc(aSize); + ExitOnFailure(p); + return p; + } + + template <typename T> + static T* pod_malloc(size_t aNumElems) { + T* p = maybe_pod_malloc<T>(aNumElems); + ExitOnFailure(p); + return p; + } + + static void* calloc_(size_t aCount, size_t aSize) { + void* p = gMallocTable.calloc(aCount, aSize); + ExitOnFailure(p); + return p; + } + + template <typename T> + static T* pod_calloc(size_t aNumElems) { + T* p = maybe_pod_calloc<T>(aNumElems); + ExitOnFailure(p); + return p; + } + + static void* realloc_(void* aPtr, size_t aNewSize) { + void* p = gMallocTable.realloc(aPtr, aNewSize); + ExitOnFailure(p); + return p; + } + + template <typename T> + static T* pod_realloc(T* aPtr, size_t aOldSize, size_t aNewSize) { + T* p = maybe_pod_realloc(aPtr, aOldSize, aNewSize); + ExitOnFailure(p); + return p; + } + + static void* memalign_(size_t aAlignment, size_t aSize) { + void* p = gMallocTable.memalign(aAlignment, aSize); + ExitOnFailure(p); + return p; + } + + template <typename T> + static void free_(T* aPtr, size_t aSize = 0) { + gMallocTable.free(aPtr); + } + + static char* strdup_(const char* aStr) { + char* s = (char*)InfallibleAllocPolicy::malloc_(strlen(aStr) + 1); + strcpy(s, aStr); + return s; + } + + template <class T> + static T* new_() { + void* mem = malloc_(sizeof(T)); + return new (mem) T; + } + + template <class T, typename P1> + static T* new_(const P1& aP1) { + void* mem = malloc_(sizeof(T)); + return new (mem) T(aP1); + } + + template <class T> + static void delete_(T* aPtr) { + if (aPtr) { + aPtr->~T(); + InfallibleAllocPolicy::free_(aPtr); + } + } + + static void reportAllocOverflow() { ExitOnFailure(nullptr); } + bool checkSimulatedOOM() const { return true; } +}; + +// This is only needed because of the |const void*| vs |void*| arg mismatch. +static size_t MallocSizeOf(const void* aPtr) { + return gMallocTable.malloc_usable_size(const_cast<void*>(aPtr)); +} + +void DMDFuncs::StatusMsg(const char* aFmt, va_list aAp) { +#ifdef ANDROID + __android_log_vprint(ANDROID_LOG_INFO, "DMD", aFmt, aAp); +#else + // The +64 is easily enough for the "DMD[<pid>] " prefix and the NUL. + size_t size = strlen(aFmt) + 64; + char* fmt = (char*)InfallibleAllocPolicy::malloc_(size); + snprintf(fmt, size, "DMD[%d] %s", getpid(), aFmt); + vfprintf(stderr, fmt, aAp); + InfallibleAllocPolicy::free_(fmt); +#endif +} + +/* static */ +void InfallibleAllocPolicy::ExitOnFailure(const void* aP) { + if (!aP) { + MOZ_CRASH("DMD out of memory; aborting"); + } +} + +static double Percent(size_t part, size_t whole) { + return (whole == 0) ? 0 : 100 * (double)part / whole; +} + +// Commifies the number. +static char* Show(size_t n, char* buf, size_t buflen) { + int nc = 0, i = 0, lasti = buflen - 2; + buf[lasti + 1] = '\0'; + if (n == 0) { + buf[lasti - i] = '0'; + i++; + } else { + while (n > 0) { + if (((i - nc) % 3) == 0 && i != 0) { + buf[lasti - i] = ','; + i++; + nc++; + } + buf[lasti - i] = static_cast<char>((n % 10) + '0'); + i++; + n /= 10; + } + } + int firstCharIndex = lasti - i + 1; + + MOZ_ASSERT(firstCharIndex >= 0); + return &buf[firstCharIndex]; +} + +//--------------------------------------------------------------------------- +// Options (Part 1) +//--------------------------------------------------------------------------- + +class Options { + template <typename T> + struct NumOption { + const T mDefault; + const T mMax; + T mActual; + NumOption(T aDefault, T aMax) + : mDefault(aDefault), mMax(aMax), mActual(aDefault) {} + }; + + // DMD has several modes. These modes affect what data is recorded and + // written to the output file, and the written data affects the + // post-processing that dmd.py can do. + // + // Users specify the mode as soon as DMD starts. This leads to minimal memory + // usage and log file size. It has the disadvantage that is inflexible -- if + // you want to change modes you have to re-run DMD. But in practice changing + // modes seems to be rare, so it's not much of a problem. + // + // An alternative possibility would be to always record and output *all* the + // information needed for all modes. This would let you choose the mode when + // running dmd.py, and so you could do multiple kinds of profiling on a + // single DMD run. But if you are only interested in one of the simpler + // modes, you'd pay the price of (a) increased memory usage and (b) *very* + // large log files. + // + // Finally, another alternative possibility would be to do mode selection + // partly at DMD startup or recording, and then partly in dmd.py. This would + // give some extra flexibility at moderate memory and file size cost. But + // certain mode pairs wouldn't work, which would be confusing. + // + enum class Mode { + // For each live block, this mode outputs: size (usable and slop) and + // (possibly) and allocation stack. This mode is good for live heap + // profiling. + Live, + + // Like "Live", but for each live block it also outputs: zero or more + // report stacks. This mode is good for identifying where memory reporters + // should be added. This is the default mode. + DarkMatter, + + // Like "Live", but also outputs the same data for dead blocks. This mode + // does cumulative heap profiling, which is good for identifying where large + // amounts of short-lived allocations ("heap churn") occur. + Cumulative, + + // Like "Live", but this mode also outputs for each live block the address + // of the block and the values contained in the blocks. This mode is useful + // for investigating leaks, by helping to figure out which blocks refer to + // other blocks. This mode force-enables full stacks coverage. + Scan + }; + + // With full stacks, every heap block gets a stack trace recorded for it. + // This is complete but slow. + // + // With partial stacks, not all heap blocks will get a stack trace recorded. + // A Bernoulli trial (see mfbt/FastBernoulliTrial.h for details) is performed + // for each heap block to decide if it gets one. Because bigger heap blocks + // are more likely to get a stack trace, even though most heap *blocks* won't + // get a stack trace, most heap *bytes* will. + enum class Stacks { Full, Partial }; + + char* mDMDEnvVar; // a saved copy, for later printing + + Mode mMode; + Stacks mStacks; + bool mShowDumpStats; + + void BadArg(const char* aArg); + static const char* ValueIfMatch(const char* aArg, const char* aOptionName); + static bool GetLong(const char* aArg, const char* aOptionName, long aMin, + long aMax, long* aValue); + static bool GetBool(const char* aArg, const char* aOptionName, bool* aValue); + + public: + explicit Options(const char* aDMDEnvVar); + + bool IsLiveMode() const { return mMode == Mode::Live; } + bool IsDarkMatterMode() const { return mMode == Mode::DarkMatter; } + bool IsCumulativeMode() const { return mMode == Mode::Cumulative; } + bool IsScanMode() const { return mMode == Mode::Scan; } + + const char* ModeString() const; + + const char* DMDEnvVar() const { return mDMDEnvVar; } + + bool DoFullStacks() const { return mStacks == Stacks::Full; } + size_t ShowDumpStats() const { return mShowDumpStats; } +}; + +static Options* gOptions; + +//--------------------------------------------------------------------------- +// The global lock +//--------------------------------------------------------------------------- + +// MutexBase implements the platform-specific parts of a mutex. + +#ifdef XP_WIN + +class MutexBase { + CRITICAL_SECTION mCS; + + DISALLOW_COPY_AND_ASSIGN(MutexBase); + + public: + MutexBase() { InitializeCriticalSection(&mCS); } + ~MutexBase() { DeleteCriticalSection(&mCS); } + + void Lock() { EnterCriticalSection(&mCS); } + void Unlock() { LeaveCriticalSection(&mCS); } +}; + +#else + +class MutexBase { + pthread_mutex_t mMutex; + + MutexBase(const MutexBase&) = delete; + + const MutexBase& operator=(const MutexBase&) = delete; + + public: + MutexBase() { pthread_mutex_init(&mMutex, nullptr); } + + void Lock() { pthread_mutex_lock(&mMutex); } + void Unlock() { pthread_mutex_unlock(&mMutex); } +}; + +#endif + +class Mutex : private MutexBase { + bool mIsLocked; + + Mutex(const Mutex&) = delete; + + const Mutex& operator=(const Mutex&) = delete; + + public: + Mutex() : mIsLocked(false) {} + + void Lock() { + MutexBase::Lock(); + MOZ_ASSERT(!mIsLocked); + mIsLocked = true; + } + + void Unlock() { + MOZ_ASSERT(mIsLocked); + mIsLocked = false; + MutexBase::Unlock(); + } + + bool IsLocked() { return mIsLocked; } +}; + +// This lock must be held while manipulating global state such as +// gStackTraceTable, gLiveBlockTable, gDeadBlockTable. Note that gOptions is +// *not* protected by this lock because it is only written to by Options(), +// which is only invoked at start-up and in ResetEverything(), which is only +// used by SmokeDMD.cpp. +static Mutex* gStateLock = nullptr; + +class AutoLockState { + AutoLockState(const AutoLockState&) = delete; + + const AutoLockState& operator=(const AutoLockState&) = delete; + + public: + AutoLockState() { gStateLock->Lock(); } + ~AutoLockState() { gStateLock->Unlock(); } +}; + +class AutoUnlockState { + AutoUnlockState(const AutoUnlockState&) = delete; + + const AutoUnlockState& operator=(const AutoUnlockState&) = delete; + + public: + AutoUnlockState() { gStateLock->Unlock(); } + ~AutoUnlockState() { gStateLock->Lock(); } +}; + +//--------------------------------------------------------------------------- +// Per-thread blocking of intercepts +//--------------------------------------------------------------------------- + +// On MacOS, the first __thread/thread_local access calls malloc, which leads +// to an infinite loop. So we use pthread-based TLS instead, which somehow +// doesn't have this problem. +#if !defined(XP_DARWIN) +# define DMD_THREAD_LOCAL(T) MOZ_THREAD_LOCAL(T) +#else +# define DMD_THREAD_LOCAL(T) \ + detail::ThreadLocal<T, detail::ThreadLocalKeyStorage> +#endif + +class Thread { + // Required for allocation via InfallibleAllocPolicy::new_. + friend class InfallibleAllocPolicy; + + // When true, this blocks intercepts, which allows malloc interception + // functions to themselves call malloc. (Nb: for direct calls to malloc we + // can just use InfallibleAllocPolicy::{malloc_,new_}, but we sometimes + // indirectly call vanilla malloc via functions like MozStackWalk.) + bool mBlockIntercepts; + + Thread() : mBlockIntercepts(false) {} + + Thread(const Thread&) = delete; + + const Thread& operator=(const Thread&) = delete; + + static DMD_THREAD_LOCAL(Thread*) tlsThread; + + public: + static void Init() { + if (!tlsThread.init()) { + MOZ_CRASH(); + } + } + + static Thread* Fetch() { + Thread* t = tlsThread.get(); + if (MOZ_UNLIKELY(!t)) { + // This memory is never freed, even if the thread dies. It's a leak, but + // only a tiny one. + t = InfallibleAllocPolicy::new_<Thread>(); + tlsThread.set(t); + } + + return t; + } + + bool BlockIntercepts() { + MOZ_ASSERT(!mBlockIntercepts); + return mBlockIntercepts = true; + } + + bool UnblockIntercepts() { + MOZ_ASSERT(mBlockIntercepts); + return mBlockIntercepts = false; + } + + bool InterceptsAreBlocked() const { return mBlockIntercepts; } +}; + +DMD_THREAD_LOCAL(Thread*) Thread::tlsThread; + +// An object of this class must be created (on the stack) before running any +// code that might allocate. +class AutoBlockIntercepts { + Thread* const mT; + + AutoBlockIntercepts(const AutoBlockIntercepts&) = delete; + + const AutoBlockIntercepts& operator=(const AutoBlockIntercepts&) = delete; + + public: + explicit AutoBlockIntercepts(Thread* aT) : mT(aT) { mT->BlockIntercepts(); } + ~AutoBlockIntercepts() { + MOZ_ASSERT(mT->InterceptsAreBlocked()); + mT->UnblockIntercepts(); + } +}; + +//--------------------------------------------------------------------------- +// Location service +//--------------------------------------------------------------------------- + +struct DescribeCodeAddressLock { + static void Unlock() { gStateLock->Unlock(); } + static void Lock() { gStateLock->Lock(); } + static bool IsLocked() { return gStateLock->IsLocked(); } +}; + +typedef CodeAddressService<InfallibleAllocPolicy, DescribeCodeAddressLock> + CodeAddressService; + +//--------------------------------------------------------------------------- +// Stack traces +//--------------------------------------------------------------------------- + +class StackTrace { + public: + static const uint32_t MaxFrames = 24; + + private: + uint32_t mLength; // The number of PCs. + const void* mPcs[MaxFrames]; // The PCs themselves. + + public: + StackTrace() : mLength(0) {} + StackTrace(const StackTrace& aOther) : mLength(aOther.mLength) { + PodCopy(mPcs, aOther.mPcs, mLength); + } + + uint32_t Length() const { return mLength; } + const void* Pc(uint32_t i) const { + MOZ_ASSERT(i < mLength); + return mPcs[i]; + } + + uint32_t Size() const { return mLength * sizeof(mPcs[0]); } + + // The stack trace returned by this function is interned in gStackTraceTable, + // and so is immortal and unmovable. + static const StackTrace* Get(Thread* aT); + + // Hash policy. + + typedef StackTrace* Lookup; + + static mozilla::HashNumber hash(const StackTrace* const& aSt) { + return mozilla::HashBytes(aSt->mPcs, aSt->Size()); + } + + static bool match(const StackTrace* const& aA, const StackTrace* const& aB) { + return aA->mLength == aB->mLength && + memcmp(aA->mPcs, aB->mPcs, aA->Size()) == 0; + } + + private: + static void StackWalkCallback(uint32_t aFrameNumber, void* aPc, void* aSp, + void* aClosure) { + StackTrace* st = (StackTrace*)aClosure; + MOZ_ASSERT(st->mLength < MaxFrames); + st->mPcs[st->mLength] = aPc; + st->mLength++; + MOZ_ASSERT(st->mLength == aFrameNumber); + } +}; + +typedef mozilla::HashSet<StackTrace*, StackTrace, InfallibleAllocPolicy> + StackTraceTable; +static StackTraceTable* gStackTraceTable = nullptr; + +typedef mozilla::HashSet<const StackTrace*, + mozilla::DefaultHasher<const StackTrace*>, + InfallibleAllocPolicy> + StackTraceSet; + +typedef mozilla::HashSet<const void*, mozilla::DefaultHasher<const void*>, + InfallibleAllocPolicy> + PointerSet; +typedef mozilla::HashMap<const void*, uint32_t, + mozilla::DefaultHasher<const void*>, + InfallibleAllocPolicy> + PointerIdMap; + +// We won't GC the stack trace table until it this many elements. +static uint32_t gGCStackTraceTableWhenSizeExceeds = 4 * 1024; + +/* static */ const StackTrace* StackTrace::Get(Thread* aT) { + MOZ_ASSERT(gStateLock->IsLocked()); + MOZ_ASSERT(aT->InterceptsAreBlocked()); + + // On Windows, MozStackWalk can acquire a lock from the shared library + // loader. Another thread might call malloc while holding that lock (when + // loading a shared library). So we can't be in gStateLock during the call + // to MozStackWalk. For details, see + // https://bugzilla.mozilla.org/show_bug.cgi?id=374829#c8 + // On Linux, something similar can happen; see bug 824340. + // So let's just release it on all platforms. + StackTrace tmp; + { + AutoUnlockState unlock; + // In each of the following cases, skipFrames is chosen so that the + // first frame in each stack trace is a replace_* function (or as close as + // possible, given the vagaries of inlining on different platforms). +#if defined(XP_WIN) && defined(_M_IX86) + // This avoids MozStackWalk(), which causes unusably slow startup on Win32 + // when it is called during static initialization (see bug 1241684). + // + // This code is cribbed from the Gecko Profiler, which also uses + // FramePointerStackWalk() on Win32: REGISTERS_SYNC_POPULATE() for the + // frame pointer, and GetStackTop() for the stack end. + CONTEXT context; + RtlCaptureContext(&context); + void** fp = reinterpret_cast<void**>(context.Ebp); + + PNT_TIB pTib = reinterpret_cast<PNT_TIB>(NtCurrentTeb()); + void* stackEnd = static_cast<void*>(pTib->StackBase); + FramePointerStackWalk(StackWalkCallback, MaxFrames, &tmp, fp, stackEnd); +#elif defined(XP_MACOSX) + // This avoids MozStackWalk(), which has become unusably slow on Mac due to + // changes in libunwind. + // + // This code is cribbed from the Gecko Profiler, which also uses + // FramePointerStackWalk() on Mac: REGISTERS_SYNC_POPULATE() for the frame + // pointer, and GetStackTop() for the stack end. +# pragma GCC diagnostic push +# pragma GCC diagnostic ignored "-Wframe-address" + void** fp = reinterpret_cast<void**>(__builtin_frame_address(1)); +# pragma GCC diagnostic pop + void* stackEnd = pthread_get_stackaddr_np(pthread_self()); + FramePointerStackWalk(StackWalkCallback, MaxFrames, &tmp, fp, stackEnd); +#else + MozStackWalk(StackWalkCallback, nullptr, MaxFrames, &tmp); +#endif + } + + StackTraceTable::AddPtr p = gStackTraceTable->lookupForAdd(&tmp); + if (!p) { + StackTrace* stnew = InfallibleAllocPolicy::new_<StackTrace>(tmp); + MOZ_ALWAYS_TRUE(gStackTraceTable->add(p, stnew)); + } + return *p; +} + +//--------------------------------------------------------------------------- +// Heap blocks +//--------------------------------------------------------------------------- + +// This class combines a 2-byte-aligned pointer (i.e. one whose bottom bit +// is zero) with a 1-bit tag. +// +// |T| is the pointer type, e.g. |int*|, not the pointed-to type. This makes +// is easier to have const pointers, e.g. |TaggedPtr<const int*>|. +template <typename T> +class TaggedPtr { + union { + T mPtr; + uintptr_t mUint; + }; + + static const uintptr_t kTagMask = uintptr_t(0x1); + static const uintptr_t kPtrMask = ~kTagMask; + + static bool IsTwoByteAligned(T aPtr) { + return (uintptr_t(aPtr) & kTagMask) == 0; + } + + public: + TaggedPtr() : mPtr(nullptr) {} + + TaggedPtr(T aPtr, bool aBool) : mPtr(aPtr) { + MOZ_ASSERT(IsTwoByteAligned(aPtr)); + uintptr_t tag = uintptr_t(aBool); + MOZ_ASSERT(tag <= kTagMask); + mUint |= (tag & kTagMask); + } + + void Set(T aPtr, bool aBool) { + MOZ_ASSERT(IsTwoByteAligned(aPtr)); + mPtr = aPtr; + uintptr_t tag = uintptr_t(aBool); + MOZ_ASSERT(tag <= kTagMask); + mUint |= (tag & kTagMask); + } + + T Ptr() const { return reinterpret_cast<T>(mUint & kPtrMask); } + + bool Tag() const { return bool(mUint & kTagMask); } +}; + +// A live heap block. Stores both basic data and data about reports, if we're +// in DarkMatter mode. +class LiveBlock { + const void* mPtr; + const size_t mReqSize; // size requested + + // The stack trace where this block was allocated, or nullptr if we didn't + // record one. + const StackTrace* const mAllocStackTrace; + + // This array has two elements because we record at most two reports of a + // block. + // - Ptr: |mReportStackTrace| - stack trace where this block was reported. + // nullptr if not reported. + // - Tag bit 0: |mReportedOnAlloc| - was the block reported immediately on + // allocation? If so, DMD must not clear the report at the end of + // Analyze(). Only relevant if |mReportStackTrace| is non-nullptr. + // + // |mPtr| is used as the key in LiveBlockTable, so it's ok for this member + // to be |mutable|. + // + // Only used in DarkMatter mode. + mutable TaggedPtr<const StackTrace*> mReportStackTrace_mReportedOnAlloc[2]; + + public: + LiveBlock(const void* aPtr, size_t aReqSize, + const StackTrace* aAllocStackTrace) + : mPtr(aPtr), mReqSize(aReqSize), mAllocStackTrace(aAllocStackTrace) {} + + const void* Address() const { return mPtr; } + + size_t ReqSize() const { return mReqSize; } + + size_t SlopSize() const { return MallocSizeOf(mPtr) - mReqSize; } + + const StackTrace* AllocStackTrace() const { return mAllocStackTrace; } + + const StackTrace* ReportStackTrace1() const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + return mReportStackTrace_mReportedOnAlloc[0].Ptr(); + } + + const StackTrace* ReportStackTrace2() const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + return mReportStackTrace_mReportedOnAlloc[1].Ptr(); + } + + bool ReportedOnAlloc1() const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + return mReportStackTrace_mReportedOnAlloc[0].Tag(); + } + + bool ReportedOnAlloc2() const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + return mReportStackTrace_mReportedOnAlloc[1].Tag(); + } + + void AddStackTracesToTable(StackTraceSet& aStackTraces) const { + if (AllocStackTrace()) { + MOZ_ALWAYS_TRUE(aStackTraces.put(AllocStackTrace())); + } + if (gOptions->IsDarkMatterMode()) { + if (ReportStackTrace1()) { + MOZ_ALWAYS_TRUE(aStackTraces.put(ReportStackTrace1())); + } + if (ReportStackTrace2()) { + MOZ_ALWAYS_TRUE(aStackTraces.put(ReportStackTrace2())); + } + } + } + + uint32_t NumReports() const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + if (ReportStackTrace2()) { + MOZ_ASSERT(ReportStackTrace1()); + return 2; + } + if (ReportStackTrace1()) { + return 1; + } + return 0; + } + + // This is |const| thanks to the |mutable| fields above. + void Report(Thread* aT, bool aReportedOnAlloc) const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + // We don't bother recording reports after the 2nd one. + uint32_t numReports = NumReports(); + if (numReports < 2) { + mReportStackTrace_mReportedOnAlloc[numReports].Set(StackTrace::Get(aT), + aReportedOnAlloc); + } + } + + void UnreportIfNotReportedOnAlloc() const { + MOZ_ASSERT(gOptions->IsDarkMatterMode()); + if (!ReportedOnAlloc1() && !ReportedOnAlloc2()) { + mReportStackTrace_mReportedOnAlloc[0].Set(nullptr, 0); + mReportStackTrace_mReportedOnAlloc[1].Set(nullptr, 0); + + } else if (!ReportedOnAlloc1() && ReportedOnAlloc2()) { + // Shift the 2nd report down to the 1st one. + mReportStackTrace_mReportedOnAlloc[0] = + mReportStackTrace_mReportedOnAlloc[1]; + mReportStackTrace_mReportedOnAlloc[1].Set(nullptr, 0); + + } else if (ReportedOnAlloc1() && !ReportedOnAlloc2()) { + mReportStackTrace_mReportedOnAlloc[1].Set(nullptr, 0); + } + } + + // Hash policy. + + typedef const void* Lookup; + + static mozilla::HashNumber hash(const void* const& aPtr) { + return mozilla::HashGeneric(aPtr); + } + + static bool match(const LiveBlock& aB, const void* const& aPtr) { + return aB.mPtr == aPtr; + } +}; + +// A table of live blocks where the lookup key is the block address. +typedef mozilla::HashSet<LiveBlock, LiveBlock, InfallibleAllocPolicy> + LiveBlockTable; +static LiveBlockTable* gLiveBlockTable = nullptr; + +class AggregatedLiveBlockHashPolicy { + public: + typedef const LiveBlock* const Lookup; + + static mozilla::HashNumber hash(const LiveBlock* const& aB) { + return gOptions->IsDarkMatterMode() + ? mozilla::HashGeneric( + aB->ReqSize(), aB->SlopSize(), aB->AllocStackTrace(), + aB->ReportedOnAlloc1(), aB->ReportedOnAlloc2()) + : mozilla::HashGeneric(aB->ReqSize(), aB->SlopSize(), + aB->AllocStackTrace()); + } + + static bool match(const LiveBlock* const& aA, const LiveBlock* const& aB) { + return gOptions->IsDarkMatterMode() + ? aA->ReqSize() == aB->ReqSize() && + aA->SlopSize() == aB->SlopSize() && + aA->AllocStackTrace() == aB->AllocStackTrace() && + aA->ReportStackTrace1() == aB->ReportStackTrace1() && + aA->ReportStackTrace2() == aB->ReportStackTrace2() + : aA->ReqSize() == aB->ReqSize() && + aA->SlopSize() == aB->SlopSize() && + aA->AllocStackTrace() == aB->AllocStackTrace(); + } +}; + +// A table of live blocks where the lookup key is everything but the block +// address. For aggregating similar live blocks at output time. +typedef mozilla::HashMap<const LiveBlock*, size_t, + AggregatedLiveBlockHashPolicy, InfallibleAllocPolicy> + AggregatedLiveBlockTable; + +// A freed heap block. +class DeadBlock { + const size_t mReqSize; // size requested + const size_t mSlopSize; // slop above size requested + + // The stack trace where this block was allocated. + const StackTrace* const mAllocStackTrace; + + public: + DeadBlock() : mReqSize(0), mSlopSize(0), mAllocStackTrace(nullptr) {} + + explicit DeadBlock(const LiveBlock& aLb) + : mReqSize(aLb.ReqSize()), + mSlopSize(aLb.SlopSize()), + mAllocStackTrace(aLb.AllocStackTrace()) {} + + ~DeadBlock() = default; + + size_t ReqSize() const { return mReqSize; } + size_t SlopSize() const { return mSlopSize; } + + const StackTrace* AllocStackTrace() const { return mAllocStackTrace; } + + void AddStackTracesToTable(StackTraceSet& aStackTraces) const { + if (AllocStackTrace()) { + MOZ_ALWAYS_TRUE(aStackTraces.put(AllocStackTrace())); + } + } + + // Hash policy. + + typedef DeadBlock Lookup; + + static mozilla::HashNumber hash(const DeadBlock& aB) { + return mozilla::HashGeneric(aB.ReqSize(), aB.SlopSize(), + aB.AllocStackTrace()); + } + + static bool match(const DeadBlock& aA, const DeadBlock& aB) { + return aA.ReqSize() == aB.ReqSize() && aA.SlopSize() == aB.SlopSize() && + aA.AllocStackTrace() == aB.AllocStackTrace(); + } +}; + +// For each unique DeadBlock value we store a count of how many actual dead +// blocks have that value. +typedef mozilla::HashMap<DeadBlock, size_t, DeadBlock, InfallibleAllocPolicy> + DeadBlockTable; +static DeadBlockTable* gDeadBlockTable = nullptr; + +// Add the dead block to the dead block table, if that's appropriate. +void MaybeAddToDeadBlockTable(const DeadBlock& aDb) { + if (gOptions->IsCumulativeMode() && aDb.AllocStackTrace()) { + AutoLockState lock; + if (DeadBlockTable::AddPtr p = gDeadBlockTable->lookupForAdd(aDb)) { + p->value() += 1; + } else { + MOZ_ALWAYS_TRUE(gDeadBlockTable->add(p, aDb, 1)); + } + } +} + +// Add a pointer to each live stack trace into the given StackTraceSet. (A +// stack trace is live if it's used by one of the live blocks.) +static void GatherUsedStackTraces(StackTraceSet& aStackTraces) { + MOZ_ASSERT(gStateLock->IsLocked()); + MOZ_ASSERT(Thread::Fetch()->InterceptsAreBlocked()); + + aStackTraces.clear(); + MOZ_ALWAYS_TRUE(aStackTraces.reserve(512)); + + for (auto iter = gLiveBlockTable->iter(); !iter.done(); iter.next()) { + iter.get().AddStackTracesToTable(aStackTraces); + } + + for (auto iter = gDeadBlockTable->iter(); !iter.done(); iter.next()) { + iter.get().key().AddStackTracesToTable(aStackTraces); + } +} + +// Delete stack traces that we aren't using, and compact our hashtable. +static void GCStackTraces() { + MOZ_ASSERT(gStateLock->IsLocked()); + MOZ_ASSERT(Thread::Fetch()->InterceptsAreBlocked()); + + StackTraceSet usedStackTraces; + GatherUsedStackTraces(usedStackTraces); + + // Delete all unused stack traces from gStackTraceTable. The ModIterator + // destructor will automatically rehash and compact the table. + for (auto iter = gStackTraceTable->modIter(); !iter.done(); iter.next()) { + StackTrace* const& st = iter.get(); + if (!usedStackTraces.has(st)) { + iter.remove(); + InfallibleAllocPolicy::delete_(st); + } + } + + // Schedule a GC when we have twice as many stack traces as we had right after + // this GC finished. + gGCStackTraceTableWhenSizeExceeds = 2 * gStackTraceTable->count(); +} + +//--------------------------------------------------------------------------- +// malloc/free callbacks +//--------------------------------------------------------------------------- + +static FastBernoulliTrial* gBernoulli; + +// In testing, a probability of 0.003 resulted in ~25% of heap blocks getting +// a stack trace and ~80% of heap bytes getting a stack trace. (This is +// possible because big heap blocks are more likely to get a stack trace.) +// +// We deliberately choose not to give the user control over this probability +// (other than effectively setting it to 1 via --stacks=full) because it's +// quite inscrutable and generally the user just wants "faster and imprecise" +// or "slower and precise". +// +// The random number seeds are arbitrary and were obtained from random.org. If +// you change them you'll need to change the tests as well, because their +// expected output is based on the particular sequence of trial results that we +// get with these seeds. +static void ResetBernoulli() { + new (gBernoulli) + FastBernoulliTrial(0.003, 0x8e26eeee166bc8ca, 0x56820f304a9c9ae0); +} + +static void AllocCallback(void* aPtr, size_t aReqSize, Thread* aT) { + if (!aPtr) { + return; + } + + AutoLockState lock; + AutoBlockIntercepts block(aT); + + size_t actualSize = gMallocTable.malloc_usable_size(aPtr); + + // We may or may not record the allocation stack trace, depending on the + // options and the outcome of a Bernoulli trial. + bool getTrace = gOptions->DoFullStacks() || gBernoulli->trial(actualSize); + LiveBlock b(aPtr, aReqSize, getTrace ? StackTrace::Get(aT) : nullptr); + LiveBlockTable::AddPtr p = gLiveBlockTable->lookupForAdd(aPtr); + if (!p) { + // Most common case: there wasn't a record already. + MOZ_ALWAYS_TRUE(gLiveBlockTable->add(p, b)); + } else { + // Edge-case: there was a record for the same address. We'll assume the + // allocator is not giving out a pointer to an existing allocation, so + // this means the previously recorded allocation was freed while we were + // blocking interceptions. This can happen while processing the data in + // e.g. AnalyzeImpl. + if (gOptions->IsCumulativeMode()) { + // Copy it out so it can be added to the dead block list later. + DeadBlock db(*p); + MaybeAddToDeadBlockTable(db); + } + gLiveBlockTable->remove(p); + MOZ_ALWAYS_TRUE(gLiveBlockTable->putNew(aPtr, b)); + } +} + +static void FreeCallback(void* aPtr, Thread* aT, DeadBlock* aDeadBlock) { + if (!aPtr) { + return; + } + + AutoLockState lock; + AutoBlockIntercepts block(aT); + + if (LiveBlockTable::Ptr lb = gLiveBlockTable->lookup(aPtr)) { + if (gOptions->IsCumulativeMode()) { + // Copy it out so it can be added to the dead block list later. + new (aDeadBlock) DeadBlock(*lb); + } + gLiveBlockTable->remove(lb); + } else { + // We have no record of the block. It must be a bogus pointer, or one that + // DMD wasn't able to see allocated. This should be extremely rare. + } + + if (gStackTraceTable->count() > gGCStackTraceTableWhenSizeExceeds) { + GCStackTraces(); + } +} + +//--------------------------------------------------------------------------- +// malloc/free interception +//--------------------------------------------------------------------------- + +static bool Init(malloc_table_t* aMallocTable); + +} // namespace dmd +} // namespace mozilla + +static void* replace_malloc(size_t aSize) { + using namespace mozilla::dmd; + + Thread* t = Thread::Fetch(); + if (t->InterceptsAreBlocked()) { + // Intercepts are blocked, which means this must be a call to malloc + // triggered indirectly by DMD (e.g. via MozStackWalk). Be infallible. + return InfallibleAllocPolicy::malloc_(aSize); + } + + // This must be a call to malloc from outside DMD. Intercept it. + void* ptr = gMallocTable.malloc(aSize); + AllocCallback(ptr, aSize, t); + return ptr; +} + +static void* replace_calloc(size_t aCount, size_t aSize) { + using namespace mozilla::dmd; + + Thread* t = Thread::Fetch(); + if (t->InterceptsAreBlocked()) { + return InfallibleAllocPolicy::calloc_(aCount, aSize); + } + + // |aCount * aSize| could overflow, but if that happens then + // |gMallocTable.calloc()| will return nullptr and |AllocCallback()| will + // return immediately without using the overflowed value. + void* ptr = gMallocTable.calloc(aCount, aSize); + AllocCallback(ptr, aCount * aSize, t); + return ptr; +} + +static void* replace_realloc(void* aOldPtr, size_t aSize) { + using namespace mozilla::dmd; + + Thread* t = Thread::Fetch(); + if (t->InterceptsAreBlocked()) { + return InfallibleAllocPolicy::realloc_(aOldPtr, aSize); + } + + // If |aOldPtr| is nullptr, the call is equivalent to |malloc(aSize)|. + if (!aOldPtr) { + return replace_malloc(aSize); + } + + // Be very careful here! Must remove the block from the table before doing + // the realloc to avoid races, just like in replace_free(). + // Nb: This does an unnecessary hashtable remove+add if the block doesn't + // move, but doing better isn't worth the effort. + DeadBlock db; + FreeCallback(aOldPtr, t, &db); + void* ptr = gMallocTable.realloc(aOldPtr, aSize); + if (ptr) { + AllocCallback(ptr, aSize, t); + MaybeAddToDeadBlockTable(db); + } else { + // If realloc fails, we undo the prior operations by re-inserting the old + // pointer into the live block table. We don't have to do anything with the + // dead block list because the dead block hasn't yet been inserted. The + // block will end up looking like it was allocated for the first time here, + // which is untrue, and the slop bytes will be zero, which may be untrue. + // But this case is rare and doing better isn't worth the effort. + AllocCallback(aOldPtr, gMallocTable.malloc_usable_size(aOldPtr), t); + } + return ptr; +} + +static void* replace_memalign(size_t aAlignment, size_t aSize) { + using namespace mozilla::dmd; + + Thread* t = Thread::Fetch(); + if (t->InterceptsAreBlocked()) { + return InfallibleAllocPolicy::memalign_(aAlignment, aSize); + } + + void* ptr = gMallocTable.memalign(aAlignment, aSize); + AllocCallback(ptr, aSize, t); + return ptr; +} + +static void replace_free(void* aPtr) { + using namespace mozilla::dmd; + + Thread* t = Thread::Fetch(); + if (t->InterceptsAreBlocked()) { + return InfallibleAllocPolicy::free_(aPtr); + } + + // Do the actual free after updating the table. Otherwise, another thread + // could call malloc and get the freed block and update the table, and then + // our update here would remove the newly-malloc'd block. + DeadBlock db; + FreeCallback(aPtr, t, &db); + MaybeAddToDeadBlockTable(db); + gMallocTable.free(aPtr); +} + +void replace_init(malloc_table_t* aMallocTable, ReplaceMallocBridge** aBridge) { + if (mozilla::dmd::Init(aMallocTable)) { +#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC_BASE +#define MALLOC_DECL(name, ...) aMallocTable->name = replace_##name; +#include "malloc_decls.h" + *aBridge = mozilla::dmd::gDMDBridge; + } +} + +namespace mozilla { +namespace dmd { + +//--------------------------------------------------------------------------- +// Options (Part 2) +//--------------------------------------------------------------------------- + +// Given an |aOptionName| like "foo", succeed if |aArg| has the form "foo=blah" +// (where "blah" is non-empty) and return the pointer to "blah". |aArg| can +// have leading space chars (but not other whitespace). +const char* Options::ValueIfMatch(const char* aArg, const char* aOptionName) { + MOZ_ASSERT(!isspace(*aArg)); // any leading whitespace should not remain + size_t optionLen = strlen(aOptionName); + if (strncmp(aArg, aOptionName, optionLen) == 0 && aArg[optionLen] == '=' && + aArg[optionLen + 1]) { + return aArg + optionLen + 1; + } + return nullptr; +} + +// Extracts a |long| value for an option from an argument. It must be within +// the range |aMin..aMax| (inclusive). +bool Options::GetLong(const char* aArg, const char* aOptionName, long aMin, + long aMax, long* aValue) { + if (const char* optionValue = ValueIfMatch(aArg, aOptionName)) { + char* endPtr; + *aValue = strtol(optionValue, &endPtr, /* base */ 10); + if (!*endPtr && aMin <= *aValue && *aValue <= aMax && *aValue != LONG_MIN && + *aValue != LONG_MAX) { + return true; + } + } + return false; +} + +// Extracts a |bool| value for an option -- encoded as "yes" or "no" -- from an +// argument. +bool Options::GetBool(const char* aArg, const char* aOptionName, bool* aValue) { + if (const char* optionValue = ValueIfMatch(aArg, aOptionName)) { + if (strcmp(optionValue, "yes") == 0) { + *aValue = true; + return true; + } + if (strcmp(optionValue, "no") == 0) { + *aValue = false; + return true; + } + } + return false; +} + +Options::Options(const char* aDMDEnvVar) + : mDMDEnvVar(aDMDEnvVar ? InfallibleAllocPolicy::strdup_(aDMDEnvVar) + : nullptr), + mMode(Mode::DarkMatter), + mStacks(Stacks::Partial), + mShowDumpStats(false) { + char* e = mDMDEnvVar; + if (e && strcmp(e, "1") != 0) { + bool isEnd = false; + while (!isEnd) { + // Consume leading whitespace. + while (isspace(*e)) { + e++; + } + + // Save the start of the arg. + const char* arg = e; + + // Find the first char after the arg, and temporarily change it to '\0' + // to isolate the arg. + while (!isspace(*e) && *e != '\0') { + e++; + } + char replacedChar = *e; + isEnd = replacedChar == '\0'; + *e = '\0'; + + // Handle arg + bool myBool; + if (strcmp(arg, "--mode=live") == 0) { + mMode = Mode::Live; + } else if (strcmp(arg, "--mode=dark-matter") == 0) { + mMode = Mode::DarkMatter; + } else if (strcmp(arg, "--mode=cumulative") == 0) { + mMode = Mode::Cumulative; + } else if (strcmp(arg, "--mode=scan") == 0) { + mMode = Mode::Scan; + + } else if (strcmp(arg, "--stacks=full") == 0) { + mStacks = Stacks::Full; + } else if (strcmp(arg, "--stacks=partial") == 0) { + mStacks = Stacks::Partial; + + } else if (GetBool(arg, "--show-dump-stats", &myBool)) { + mShowDumpStats = myBool; + + } else if (strcmp(arg, "") == 0) { + // This can only happen if there is trailing whitespace. Ignore. + MOZ_ASSERT(isEnd); + + } else { + BadArg(arg); + } + + // Undo the temporary isolation. + *e = replacedChar; + } + } + + if (mMode == Mode::Scan) { + mStacks = Stacks::Full; + } +} + +void Options::BadArg(const char* aArg) { + StatusMsg("\n"); + StatusMsg("Bad entry in the $DMD environment variable: '%s'.\n", aArg); + StatusMsg("See the output of |mach help run| for the allowed options.\n"); + exit(1); +} + +const char* Options::ModeString() const { + switch (mMode) { + case Mode::Live: + return "live"; + case Mode::DarkMatter: + return "dark-matter"; + case Mode::Cumulative: + return "cumulative"; + case Mode::Scan: + return "scan"; + default: + MOZ_ASSERT(false); + return "(unknown DMD mode)"; + } +} + +//--------------------------------------------------------------------------- +// DMD start-up +//--------------------------------------------------------------------------- + +#ifndef XP_WIN +static void prefork() { + if (gStateLock) { + gStateLock->Lock(); + } +} + +static void postfork() { + if (gStateLock) { + gStateLock->Unlock(); + } +} +#endif + +// WARNING: this function runs *very* early -- before all static initializers +// have run. For this reason, non-scalar globals such as gStateLock and +// gStackTraceTable are allocated dynamically (so we can guarantee their +// construction in this function) rather than statically. +static bool Init(malloc_table_t* aMallocTable) { + // DMD is controlled by the |DMD| environment variable. + const char* e = getenv("DMD"); + + if (!e) { + return false; + } + // Initialize the function table first, because StatusMsg uses + // InfallibleAllocPolicy::malloc_, which uses it. + gMallocTable = *aMallocTable; + + StatusMsg("$DMD = '%s'\n", e); + + gDMDBridge = InfallibleAllocPolicy::new_<DMDBridge>(); + +#ifndef XP_WIN + // Avoid deadlocks when forking by acquiring our state lock prior to forking + // and releasing it after forking. See |LogAlloc|'s |replace_init| for + // in-depth details. + // + // Note: This must run after attempting an allocation so as to give the + // system malloc a chance to insert its own atfork handler. + pthread_atfork(prefork, postfork, postfork); +#endif + // Parse $DMD env var. + gOptions = InfallibleAllocPolicy::new_<Options>(e); + + gStateLock = InfallibleAllocPolicy::new_<Mutex>(); + + gBernoulli = (FastBernoulliTrial*)InfallibleAllocPolicy::malloc_( + sizeof(FastBernoulliTrial)); + ResetBernoulli(); + + Thread::Init(); + + { + AutoLockState lock; + + gStackTraceTable = InfallibleAllocPolicy::new_<StackTraceTable>(8192); + gLiveBlockTable = InfallibleAllocPolicy::new_<LiveBlockTable>(8192); + + // Create this even if the mode isn't Cumulative (albeit with a small + // size), in case the mode is changed later on (as is done by SmokeDMD.cpp, + // for example). + size_t tableSize = gOptions->IsCumulativeMode() ? 8192 : 4; + gDeadBlockTable = InfallibleAllocPolicy::new_<DeadBlockTable>(tableSize); + } + + return true; +} + +//--------------------------------------------------------------------------- +// Block reporting and unreporting +//--------------------------------------------------------------------------- + +static void ReportHelper(const void* aPtr, bool aReportedOnAlloc) { + if (!gOptions->IsDarkMatterMode() || !aPtr) { + return; + } + + Thread* t = Thread::Fetch(); + + AutoBlockIntercepts block(t); + AutoLockState lock; + + if (LiveBlockTable::Ptr p = gLiveBlockTable->lookup(aPtr)) { + p->Report(t, aReportedOnAlloc); + } else { + // We have no record of the block. It must be a bogus pointer. This should + // be extremely rare because Report() is almost always called in + // conjunction with a malloc_size_of-style function. Print a message so + // that we get some feedback. + StatusMsg("Unknown pointer %p\n", aPtr); + } +} + +void DMDFuncs::Report(const void* aPtr) { + ReportHelper(aPtr, /* onAlloc */ false); +} + +void DMDFuncs::ReportOnAlloc(const void* aPtr) { + ReportHelper(aPtr, /* onAlloc */ true); +} + +//--------------------------------------------------------------------------- +// DMD output +//--------------------------------------------------------------------------- + +// The version number of the output format. Increment this if you make +// backwards-incompatible changes to the format. See DMD.h for the version +// history. +static const int kOutputVersionNumber = 5; + +// Note that, unlike most SizeOf* functions, this function does not take a +// |mozilla::MallocSizeOf| argument. That's because those arguments are +// primarily to aid DMD track heap blocks... but DMD deliberately doesn't track +// heap blocks it allocated for itself! +// +// SizeOfInternal should be called while you're holding the state lock and +// while intercepts are blocked; SizeOf acquires the lock and blocks +// intercepts. + +static void SizeOfInternal(Sizes* aSizes) { + MOZ_ASSERT(gStateLock->IsLocked()); + MOZ_ASSERT(Thread::Fetch()->InterceptsAreBlocked()); + + aSizes->Clear(); + + StackTraceSet usedStackTraces; + GatherUsedStackTraces(usedStackTraces); + + for (auto iter = gStackTraceTable->iter(); !iter.done(); iter.next()) { + StackTrace* const& st = iter.get(); + + if (usedStackTraces.has(st)) { + aSizes->mStackTracesUsed += MallocSizeOf(st); + } else { + aSizes->mStackTracesUnused += MallocSizeOf(st); + } + } + + aSizes->mStackTraceTable = + gStackTraceTable->shallowSizeOfIncludingThis(MallocSizeOf); + + aSizes->mLiveBlockTable = + gLiveBlockTable->shallowSizeOfIncludingThis(MallocSizeOf); + + aSizes->mDeadBlockTable = + gDeadBlockTable->shallowSizeOfIncludingThis(MallocSizeOf); +} + +void DMDFuncs::SizeOf(Sizes* aSizes) { + aSizes->Clear(); + + AutoBlockIntercepts block(Thread::Fetch()); + AutoLockState lock; + SizeOfInternal(aSizes); +} + +void DMDFuncs::ClearReports() { + if (!gOptions->IsDarkMatterMode()) { + return; + } + + AutoLockState lock; + + // Unreport all blocks that were marked reported by a memory reporter. This + // excludes those that were reported on allocation, because they need to keep + // their reported marking. + for (auto iter = gLiveBlockTable->iter(); !iter.done(); iter.next()) { + iter.get().UnreportIfNotReportedOnAlloc(); + } +} + +class ToIdStringConverter final { + public: + ToIdStringConverter() : mIdMap(512), mNextId(0) {} + + // Converts a pointer to a unique ID. Reuses the existing ID for the pointer + // if it's been seen before. + const char* ToIdString(const void* aPtr) { + uint32_t id; + PointerIdMap::AddPtr p = mIdMap.lookupForAdd(aPtr); + if (!p) { + id = mNextId++; + MOZ_ALWAYS_TRUE(mIdMap.add(p, aPtr, id)); + } else { + id = p->value(); + } + return Base32(id); + } + + size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const { + return mIdMap.shallowSizeOfExcludingThis(aMallocSizeOf); + } + + private: + // This function converts an integer to base-32. We use base-32 values for + // indexing into the traceTable and the frameTable, for the following reasons. + // + // - Base-32 gives more compact indices than base-16. + // + // - 32 is a power-of-two, which makes the necessary div/mod calculations + // fast. + // + // - We can (and do) choose non-numeric digits for base-32. When + // inspecting/debugging the JSON output, non-numeric indices are easier to + // search for than numeric indices. + // + char* Base32(uint32_t aN) { + static const char digits[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef"; + + char* b = mIdBuf + kIdBufLen - 1; + *b = '\0'; + do { + b--; + if (b == mIdBuf) { + MOZ_CRASH("Base32 buffer too small"); + } + *b = digits[aN % 32]; + aN /= 32; + } while (aN); + + return b; + } + + PointerIdMap mIdMap; + uint32_t mNextId; + + // |mIdBuf| must have space for at least eight chars, which is the space + // needed to hold 'Dffffff' (including the terminating null char), which is + // the base-32 representation of 0xffffffff. + static const size_t kIdBufLen = 16; + char mIdBuf[kIdBufLen]; +}; + +// Helper class for converting a pointer value to a string. +class ToStringConverter { + public: + const char* ToPtrString(const void* aPtr) { + snprintf(kPtrBuf, sizeof(kPtrBuf) - 1, "%" PRIxPTR, (uintptr_t)aPtr); + return kPtrBuf; + } + + private: + char kPtrBuf[32]; +}; + +static void WriteBlockContents(JSONWriter& aWriter, const LiveBlock& aBlock) { + size_t numWords = aBlock.ReqSize() / sizeof(uintptr_t*); + if (numWords == 0) { + return; + } + + aWriter.StartArrayProperty("contents", aWriter.SingleLineStyle); + { + const uintptr_t** block = (const uintptr_t**)aBlock.Address(); + ToStringConverter sc; + for (size_t i = 0; i < numWords; ++i) { + aWriter.StringElement(MakeStringSpan(sc.ToPtrString(block[i]))); + } + } + aWriter.EndArray(); +} + +static void AnalyzeImpl(UniquePtr<JSONWriteFunc> aWriter) { + // Some blocks may have been allocated while creating |aWriter|. Those blocks + // will be freed at the end of this function when |write| is destroyed. The + // allocations will have occurred while intercepts were not blocked, so the + // frees better be as well, otherwise we'll get assertion failures. + // Therefore, this declaration must precede the AutoBlockIntercepts + // declaration, to ensure that |write| is destroyed *after* intercepts are + // unblocked. + JSONWriter writer(std::move(aWriter)); + + AutoBlockIntercepts block(Thread::Fetch()); + AutoLockState lock; + + // Allocate this on the heap instead of the stack because it's fairly large. + auto locService = InfallibleAllocPolicy::new_<CodeAddressService>(); + + StackTraceSet usedStackTraces(512); + PointerSet usedPcs(512); + + size_t iscSize; + + static int analysisCount = 1; + StatusMsg("Dump %d {\n", analysisCount++); + + writer.Start(); + { + writer.IntProperty("version", kOutputVersionNumber); + + writer.StartObjectProperty("invocation"); + { + const char* var = gOptions->DMDEnvVar(); + if (var) { + writer.StringProperty("dmdEnvVar", MakeStringSpan(var)); + } else { + writer.NullProperty("dmdEnvVar"); + } + + writer.StringProperty("mode", MakeStringSpan(gOptions->ModeString())); + } + writer.EndObject(); + + StatusMsg(" Constructing the heap block list...\n"); + + ToIdStringConverter isc; + ToStringConverter sc; + + writer.StartArrayProperty("blockList"); + { + // Lambda that writes out a live block. + auto writeLiveBlock = [&](const LiveBlock& aB, size_t aNum) { + aB.AddStackTracesToTable(usedStackTraces); + + MOZ_ASSERT_IF(gOptions->IsScanMode(), aNum == 1); + + writer.StartObjectElement(writer.SingleLineStyle); + { + if (gOptions->IsScanMode()) { + writer.StringProperty("addr", + MakeStringSpan(sc.ToPtrString(aB.Address()))); + WriteBlockContents(writer, aB); + } + writer.IntProperty("req", aB.ReqSize()); + if (aB.SlopSize() > 0) { + writer.IntProperty("slop", aB.SlopSize()); + } + + if (aB.AllocStackTrace()) { + writer.StringProperty( + "alloc", MakeStringSpan(isc.ToIdString(aB.AllocStackTrace()))); + } + + if (gOptions->IsDarkMatterMode() && aB.NumReports() > 0) { + writer.StartArrayProperty("reps"); + { + if (aB.ReportStackTrace1()) { + writer.StringElement( + MakeStringSpan(isc.ToIdString(aB.ReportStackTrace1()))); + } + if (aB.ReportStackTrace2()) { + writer.StringElement( + MakeStringSpan(isc.ToIdString(aB.ReportStackTrace2()))); + } + } + writer.EndArray(); + } + + if (aNum > 1) { + writer.IntProperty("num", aNum); + } + } + writer.EndObject(); + }; + + // Live blocks. + if (!gOptions->IsScanMode()) { + // At this point we typically have many LiveBlocks that differ only in + // their address. Aggregate them to reduce the size of the output file. + AggregatedLiveBlockTable agg(8192); + for (auto iter = gLiveBlockTable->iter(); !iter.done(); iter.next()) { + const LiveBlock& b = iter.get(); + b.AddStackTracesToTable(usedStackTraces); + + if (AggregatedLiveBlockTable::AddPtr p = agg.lookupForAdd(&b)) { + p->value() += 1; + } else { + MOZ_ALWAYS_TRUE(agg.add(p, &b, 1)); + } + } + + // Now iterate over the aggregated table. + for (auto iter = agg.iter(); !iter.done(); iter.next()) { + const LiveBlock& b = *iter.get().key(); + size_t num = iter.get().value(); + writeLiveBlock(b, num); + } + + } else { + // In scan mode we cannot aggregate because we print each live block's + // address and contents. + for (auto iter = gLiveBlockTable->iter(); !iter.done(); iter.next()) { + const LiveBlock& b = iter.get(); + b.AddStackTracesToTable(usedStackTraces); + + writeLiveBlock(b, 1); + } + } + + // Dead blocks. + for (auto iter = gDeadBlockTable->iter(); !iter.done(); iter.next()) { + const DeadBlock& b = iter.get().key(); + b.AddStackTracesToTable(usedStackTraces); + + size_t num = iter.get().value(); + MOZ_ASSERT(num > 0); + + writer.StartObjectElement(writer.SingleLineStyle); + { + writer.IntProperty("req", b.ReqSize()); + if (b.SlopSize() > 0) { + writer.IntProperty("slop", b.SlopSize()); + } + if (b.AllocStackTrace()) { + writer.StringProperty( + "alloc", MakeStringSpan(isc.ToIdString(b.AllocStackTrace()))); + } + + if (num > 1) { + writer.IntProperty("num", num); + } + } + writer.EndObject(); + } + } + writer.EndArray(); + + StatusMsg(" Constructing the stack trace table...\n"); + + writer.StartObjectProperty("traceTable"); + { + for (auto iter = usedStackTraces.iter(); !iter.done(); iter.next()) { + const StackTrace* const st = iter.get(); + writer.StartArrayProperty(MakeStringSpan(isc.ToIdString(st)), + writer.SingleLineStyle); + { + for (uint32_t i = 0; i < st->Length(); i++) { + const void* pc = st->Pc(i); + writer.StringElement(MakeStringSpan(isc.ToIdString(pc))); + MOZ_ALWAYS_TRUE(usedPcs.put(pc)); + } + } + writer.EndArray(); + } + } + writer.EndObject(); + + StatusMsg(" Constructing the stack frame table...\n"); + + writer.StartObjectProperty("frameTable"); + { + static const size_t locBufLen = 1024; + char locBuf[locBufLen]; + + for (auto iter = usedPcs.iter(); !iter.done(); iter.next()) { + const void* const pc = iter.get(); + + // Use 0 for the frame number. See the JSON format description comment + // in DMD.h to understand why. + locService->GetLocation(0, pc, locBuf, locBufLen); + writer.StringProperty(MakeStringSpan(isc.ToIdString(pc)), + MakeStringSpan(locBuf)); + } + } + writer.EndObject(); + + iscSize = isc.sizeOfExcludingThis(MallocSizeOf); + } + writer.End(); + + if (gOptions->ShowDumpStats()) { + Sizes sizes; + SizeOfInternal(&sizes); + + static const size_t kBufLen = 64; + char buf1[kBufLen]; + char buf2[kBufLen]; + char buf3[kBufLen]; + + StatusMsg(" Execution measurements {\n"); + + StatusMsg(" Data structures that persist after Dump() ends {\n"); + + StatusMsg(" Used stack traces: %10s bytes\n", + Show(sizes.mStackTracesUsed, buf1, kBufLen)); + + StatusMsg(" Unused stack traces: %10s bytes\n", + Show(sizes.mStackTracesUnused, buf1, kBufLen)); + + StatusMsg(" Stack trace table: %10s bytes (%s entries, %s used)\n", + Show(sizes.mStackTraceTable, buf1, kBufLen), + Show(gStackTraceTable->capacity(), buf2, kBufLen), + Show(gStackTraceTable->count(), buf3, kBufLen)); + + StatusMsg(" Live block table: %10s bytes (%s entries, %s used)\n", + Show(sizes.mLiveBlockTable, buf1, kBufLen), + Show(gLiveBlockTable->capacity(), buf2, kBufLen), + Show(gLiveBlockTable->count(), buf3, kBufLen)); + + StatusMsg(" Dead block table: %10s bytes (%s entries, %s used)\n", + Show(sizes.mDeadBlockTable, buf1, kBufLen), + Show(gDeadBlockTable->capacity(), buf2, kBufLen), + Show(gDeadBlockTable->count(), buf3, kBufLen)); + + StatusMsg(" }\n"); + StatusMsg(" Data structures that are destroyed after Dump() ends {\n"); + + StatusMsg( + " Location service: %10s bytes\n", + Show(locService->SizeOfIncludingThis(MallocSizeOf), buf1, kBufLen)); + StatusMsg(" Used stack traces set: %10s bytes\n", + Show(usedStackTraces.shallowSizeOfExcludingThis(MallocSizeOf), + buf1, kBufLen)); + StatusMsg( + " Used PCs set: %10s bytes\n", + Show(usedPcs.shallowSizeOfExcludingThis(MallocSizeOf), buf1, kBufLen)); + StatusMsg(" Pointer ID map: %10s bytes\n", + Show(iscSize, buf1, kBufLen)); + + StatusMsg(" }\n"); + StatusMsg(" Counts {\n"); + + size_t hits = locService->NumCacheHits(); + size_t misses = locService->NumCacheMisses(); + size_t requests = hits + misses; + StatusMsg(" Location service: %10s requests\n", + Show(requests, buf1, kBufLen)); + + size_t count = locService->CacheCount(); + size_t capacity = locService->CacheCapacity(); + StatusMsg( + " Location service cache: " + "%4.1f%% hit rate, %.1f%% occupancy at end\n", + Percent(hits, requests), Percent(count, capacity)); + + StatusMsg(" }\n"); + StatusMsg(" }\n"); + } + + InfallibleAllocPolicy::delete_(locService); + + StatusMsg("}\n"); +} + +void DMDFuncs::Analyze(UniquePtr<JSONWriteFunc> aWriter) { + AnalyzeImpl(std::move(aWriter)); + ClearReports(); +} + +//--------------------------------------------------------------------------- +// Testing +//--------------------------------------------------------------------------- + +void DMDFuncs::ResetEverything(const char* aOptions) { + AutoLockState lock; + + // Reset options. + InfallibleAllocPolicy::delete_(gOptions); + gOptions = InfallibleAllocPolicy::new_<Options>(aOptions); + + // Clear all existing blocks. + gLiveBlockTable->clear(); + gDeadBlockTable->clear(); + + // Reset gBernoulli to a deterministic state. (Its current state depends on + // all previous trials.) + ResetBernoulli(); +} + +} // namespace dmd +} // namespace mozilla |