diff options
Diffstat (limited to 'tools/profiler/lul/LulMain.h')
| -rw-r--r-- | tools/profiler/lul/LulMain.h | 397 |
1 files changed, 0 insertions, 397 deletions
diff --git a/tools/profiler/lul/LulMain.h b/tools/profiler/lul/LulMain.h deleted file mode 100644 index 0916d1b269..0000000000 --- a/tools/profiler/lul/LulMain.h +++ /dev/null @@ -1,397 +0,0 @@ -/* -*- 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 LulMain_h -#define LulMain_h - -#include "LulPlatformMacros.h" -#include "mozilla/Atomics.h" - -// LUL: A Lightweight Unwind Library. -// This file provides the end-user (external) interface for LUL. - -// Some comments about naming in the implementation. These are safe -// to ignore if you are merely using LUL, but are important if you -// hack on its internals. -// -// Debuginfo readers in general have tended to use the word "address" -// to mean several different things. This sometimes makes them -// difficult to understand and maintain. LUL tries hard to avoid -// using the word "address" and instead uses the following more -// precise terms: -// -// * SVMA ("Stated Virtual Memory Address"): this is an address of a -// symbol (etc) as it is stated in the symbol table, or other -// metadata, of an object. Such values are typically small and -// start from zero or thereabouts, unless the object has been -// prelinked. -// -// * AVMA ("Actual Virtual Memory Address"): this is the address of a -// symbol (etc) in a running process, that is, once the associated -// object has been mapped into a process. Such values are typically -// much larger than SVMAs, since objects can get mapped arbitrarily -// far along the address space. -// -// * "Bias": the difference between AVMA and SVMA for a given symbol -// (specifically, AVMA - SVMA). The bias is always an integral -// number of pages. Once we know the bias for a given object's -// text section (for example), we can compute the AVMAs of all of -// its text symbols by adding the bias to their SVMAs. -// -// * "Image address": typically, to read debuginfo from an object we -// will temporarily mmap in the file so as to read symbol tables -// etc. Addresses in this temporary mapping are called "Image -// addresses". Note that the temporary mapping is entirely -// unrelated to the mappings of the file that the dynamic linker -// must perform merely in order to get the program to run. Hence -// image addresses are unrelated to either SVMAs or AVMAs. - - -namespace lul { - -// A machine word plus validity tag. -class TaggedUWord { -public: - // RUNS IN NO-MALLOC CONTEXT - // Construct a valid one. - explicit TaggedUWord(uintptr_t w) - : mValue(w) - , mValid(true) - {} - - // RUNS IN NO-MALLOC CONTEXT - // Construct an invalid one. - TaggedUWord() - : mValue(0) - , mValid(false) - {} - - // RUNS IN NO-MALLOC CONTEXT - TaggedUWord operator+(TaggedUWord rhs) const { - return (Valid() && rhs.Valid()) ? TaggedUWord(Value() + rhs.Value()) - : TaggedUWord(); - } - - // RUNS IN NO-MALLOC CONTEXT - TaggedUWord operator-(TaggedUWord rhs) const { - return (Valid() && rhs.Valid()) ? TaggedUWord(Value() - rhs.Value()) - : TaggedUWord(); - } - - // RUNS IN NO-MALLOC CONTEXT - TaggedUWord operator&(TaggedUWord rhs) const { - return (Valid() && rhs.Valid()) ? TaggedUWord(Value() & rhs.Value()) - : TaggedUWord(); - } - - // RUNS IN NO-MALLOC CONTEXT - TaggedUWord operator|(TaggedUWord rhs) const { - return (Valid() && rhs.Valid()) ? TaggedUWord(Value() | rhs.Value()) - : TaggedUWord(); - } - - // RUNS IN NO-MALLOC CONTEXT - TaggedUWord CmpGEs(TaggedUWord rhs) const { - if (Valid() && rhs.Valid()) { - intptr_t s1 = (intptr_t)Value(); - intptr_t s2 = (intptr_t)rhs.Value(); - return TaggedUWord(s1 >= s2 ? 1 : 0); - } - return TaggedUWord(); - } - - // RUNS IN NO-MALLOC CONTEXT - TaggedUWord operator<<(TaggedUWord rhs) const { - if (Valid() && rhs.Valid()) { - uintptr_t shift = rhs.Value(); - if (shift < 8 * sizeof(uintptr_t)) - return TaggedUWord(Value() << shift); - } - return TaggedUWord(); - } - - // RUNS IN NO-MALLOC CONTEXT - // Is equal? Note: non-validity on either side gives non-equality. - bool operator==(TaggedUWord other) const { - return (mValid && other.Valid()) ? (mValue == other.Value()) : false; - } - - // RUNS IN NO-MALLOC CONTEXT - // Is it word-aligned? - bool IsAligned() const { - return mValid && (mValue & (sizeof(uintptr_t)-1)) == 0; - } - - // RUNS IN NO-MALLOC CONTEXT - uintptr_t Value() const { return mValue; } - - // RUNS IN NO-MALLOC CONTEXT - bool Valid() const { return mValid; } - -private: - uintptr_t mValue; - bool mValid; -}; - - -// The registers, with validity tags, that will be unwound. - -struct UnwindRegs { -#if defined(LUL_ARCH_arm) - TaggedUWord r7; - TaggedUWord r11; - TaggedUWord r12; - TaggedUWord r13; - TaggedUWord r14; - TaggedUWord r15; -#elif defined(LUL_ARCH_x64) || defined(LUL_ARCH_x86) - TaggedUWord xbp; - TaggedUWord xsp; - TaggedUWord xip; -#else -# error "Unknown plat" -#endif -}; - - -// The maximum number of bytes in a stack snapshot. This can be -// increased if necessary, but larger values cost performance, since a -// stack snapshot needs to be copied between sampling and worker -// threads for each snapshot. In practice 32k seems to be enough -// to get good backtraces. -static const size_t N_STACK_BYTES = 32768; - -// The stack chunk image that will be unwound. -struct StackImage { - // [start_avma, +len) specify the address range in the buffer. - // Obviously we require 0 <= len <= N_STACK_BYTES. - uintptr_t mStartAvma; - size_t mLen; - uint8_t mContents[N_STACK_BYTES]; -}; - - -// Statistics collection for the unwinder. -template<typename T> -class LULStats { -public: - LULStats() - : mContext(0) - , mCFI(0) - , mScanned(0) - {} - - template <typename S> - explicit LULStats(const LULStats<S>& aOther) - : mContext(aOther.mContext) - , mCFI(aOther.mCFI) - , mScanned(aOther.mScanned) - {} - - template <typename S> - LULStats<T>& operator=(const LULStats<S>& aOther) - { - mContext = aOther.mContext; - mCFI = aOther.mCFI; - mScanned = aOther.mScanned; - return *this; - } - - template <typename S> - uint32_t operator-(const LULStats<S>& aOther) { - return (mContext - aOther.mContext) + - (mCFI - aOther.mCFI) + (mScanned - aOther.mScanned); - } - - T mContext; // Number of context frames - T mCFI; // Number of CFI/EXIDX frames - T mScanned; // Number of scanned frames -}; - - -// The core unwinder library class. Just one of these is needed, and -// it can be shared by multiple unwinder threads. -// -// The library operates in one of two modes. -// -// * Admin mode. The library is this state after creation. In Admin -// mode, no unwinding may be performed. It is however allowable to -// perform administrative tasks -- primarily, loading of unwind info -// -- in this mode. In particular, it is safe for the library to -// perform dynamic memory allocation in this mode. Safe in the -// sense that there is no risk of deadlock against unwinding threads -// that might -- because of where they have been sampled -- hold the -// system's malloc lock. -// -// * Unwind mode. In this mode, calls to ::Unwind may be made, but -// nothing else. ::Unwind guarantees not to make any dynamic memory -// requests, so as to guarantee that the calling thread won't -// deadlock in the case where it already holds the system's malloc lock. -// -// The library is created in Admin mode. After debuginfo is loaded, -// the caller must switch it into Unwind mode by calling -// ::EnableUnwinding. There is no way to switch it back to Admin mode -// after that. To safely switch back to Admin mode would require the -// caller (or other external agent) to guarantee that there are no -// pending ::Unwind calls. - -class PriMap; -class SegArray; -class UniqueStringUniverse; - -class LUL { -public: - // Create; supply a logging sink. Sets the object in Admin mode. - explicit LUL(void (*aLog)(const char*)); - - // Destroy. Caller is responsible for ensuring that no other - // threads are in Unwind calls. All resources are freed and all - // registered unwinder threads are deregistered. Can be called - // either in Admin or Unwind mode. - ~LUL(); - - // Notify the library that unwinding is now allowed and so - // admin-mode calls are no longer allowed. The object is initially - // created in admin mode. The only possible transition is - // admin->unwinding, therefore. - void EnableUnwinding(); - - // Notify of a new r-x mapping, and load the associated unwind info. - // The filename is strdup'd and used for debug printing. If - // aMappedImage is NULL, this function will mmap/munmap the file - // itself, so as to be able to read the unwind info. If - // aMappedImage is non-NULL then it is assumed to point to a - // called-supplied and caller-managed mapped image of the file. - // May only be called in Admin mode. - void NotifyAfterMap(uintptr_t aRXavma, size_t aSize, - const char* aFileName, const void* aMappedImage); - - // In rare cases we know an executable area exists but don't know - // what the associated file is. This call notifies LUL of such - // areas. This is important for correct functioning of stack - // scanning and of the x86-{linux,android} special-case - // __kernel_syscall function handling. - // This must be called only after the code area in - // question really has been mapped. - // May only be called in Admin mode. - void NotifyExecutableArea(uintptr_t aRXavma, size_t aSize); - - // Notify that a mapped area has been unmapped; discard any - // associated unwind info. Acquires mRWlock for writing. Note that - // to avoid segfaulting the stack-scan unwinder, which inspects code - // areas, this must be called before the code area in question is - // really unmapped. Note that, unlike NotifyAfterMap(), this - // function takes the start and end addresses of the range to be - // unmapped, rather than a start and a length parameter. This is so - // as to make it possible to notify an unmap for the entire address - // space using a single call. - // May only be called in Admin mode. - void NotifyBeforeUnmap(uintptr_t aAvmaMin, uintptr_t aAvmaMax); - - // Apply NotifyBeforeUnmap to the entire address space. This causes - // LUL to discard all unwind and executable-area information for the - // entire address space. - // May only be called in Admin mode. - void NotifyBeforeUnmapAll() { - NotifyBeforeUnmap(0, UINTPTR_MAX); - } - - // Returns the number of mappings currently registered. - // May only be called in Admin mode. - size_t CountMappings(); - - // Unwind |aStackImg| starting with the context in |aStartRegs|. - // Write the number of frames recovered in *aFramesUsed. Put - // the PC values in aFramePCs[0 .. *aFramesUsed-1] and - // the SP values in aFrameSPs[0 .. *aFramesUsed-1]. - // |aFramesAvail| is the size of the two output arrays and hence the - // largest possible value of *aFramesUsed. PC values are always - // valid, and the unwind will stop when the PC becomes invalid, but - // the SP values might be invalid, in which case the value zero will - // be written in the relevant frameSPs[] slot. - // - // Unwinding may optionally use stack scanning. The maximum number - // of frames that may be recovered by stack scanning is - // |aScannedFramesAllowed| and the actual number recovered is - // written into *aScannedFramesAcquired. |aScannedFramesAllowed| - // must be less than or equal to |aFramesAvail|. - // - // This function assumes that the SP values increase as it unwinds - // away from the innermost frame -- that is, that the stack grows - // down. It monitors SP values as it unwinds to check they - // decrease, so as to avoid looping on corrupted stacks. - // - // May only be called in Unwind mode. Multiple threads may unwind - // at once. LUL user is responsible for ensuring that no thread makes - // any Admin calls whilst in Unwind mode. - // MOZ_CRASHes if the calling thread is not registered for unwinding. - // - // Up to aScannedFramesAllowed stack-scanned frames may be recovered. - // - // The calling thread must previously have been registered via a call to - // RegisterSampledThread. - void Unwind(/*OUT*/uintptr_t* aFramePCs, - /*OUT*/uintptr_t* aFrameSPs, - /*OUT*/size_t* aFramesUsed, - /*OUT*/size_t* aScannedFramesAcquired, - size_t aFramesAvail, - size_t aScannedFramesAllowed, - UnwindRegs* aStartRegs, StackImage* aStackImg); - - // The logging sink. Call to send debug strings to the caller- - // specified destination. Can only be called by the Admin thread. - void (*mLog)(const char*); - - // Statistics relating to unwinding. These have to be atomic since - // unwinding can occur on different threads simultaneously. - LULStats<mozilla::Atomic<uint32_t>> mStats; - - // Possibly show the statistics. This may not be called from any - // registered sampling thread, since it involves I/O. - void MaybeShowStats(); - -private: - // The statistics counters at the point where they were last printed. - LULStats<uint32_t> mStatsPrevious; - - // Are we in admin mode? Initially |true| but changes to |false| - // once unwinding begins. - bool mAdminMode; - - // The thread ID associated with admin mode. This is the only thread - // that is allowed do perform non-Unwind calls on this object. Conversely, - // no registered Unwinding thread may be the admin thread. This is so - // as to clearly partition the one thread that may do dynamic memory - // allocation from the threads that are being sampled, since the latter - // absolutely may not do dynamic memory allocation. - int mAdminThreadId; - - // The top level mapping from code address ranges to postprocessed - // unwind info. Basically a sorted array of (addr, len, info) - // records. This field is updated by NotifyAfterMap and NotifyBeforeUnmap. - PriMap* mPriMap; - - // An auxiliary structure that records which address ranges are - // mapped r-x, for the benefit of the stack scanner. - SegArray* mSegArray; - - // A UniqueStringUniverse that holds all the strdup'd strings created - // whilst reading unwind information. This is included so as to make - // it possible to free them in ~LUL. - UniqueStringUniverse* mUSU; -}; - - -// Run unit tests on an initialised, loaded-up LUL instance, and print -// summary results on |aLUL|'s logging sink. Also return the number -// of tests run in *aNTests and the number that passed in -// *aNTestsPassed. -void -RunLulUnitTests(/*OUT*/int* aNTests, /*OUT*/int*aNTestsPassed, LUL* aLUL); - -} // namespace lul - -#endif // LulMain_h |