Implement the memory leak annotations for heap leak checker.

third_party/tcmalloc/heap-checker.h

+// Copyright (c) 2005, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Maxim Lifantsev (with design ideas by Sanjay Ghemawat)
+//
+//
+// Module for detecing heap (memory) leaks.
+//
+// For full(er) information, see doc/heap_checker.html
+//
+// This module can be linked into programs with
+// no slowdown caused by this unless you activate the leak-checker:
+//
+//    1. Set the environment variable HEAPCHEK to _type_ before
+//       running the program.
+//
+// _type_ is usually "normal" but can also be "minimal", "strict", or
+// "draconian".  (See the html file for other options, like 'local'.)
+//
+// After that, just run your binary.  If the heap-checker detects
+// a memory leak at program-exit, it will print instructions on how
+// to track down the leak.
+
+#ifndef BASE_HEAP_CHECKER_H_
+#define BASE_HEAP_CHECKER_H_
+
+#include "config.h"
+
+#include <sys/types.h>  // for size_t
+#ifdef HAVE_STDINT_H
+#include <stdint.h>     // for uintptr_t
+#endif
+#include <stdarg.h>     // for va_list
+#include <vector>
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef PERFTOOLS_DLL_DECL
+# ifdef _WIN32
+#   define PERFTOOLS_DLL_DECL  __declspec(dllimport)
+# else
+#   define PERFTOOLS_DLL_DECL
+# endif
+#endif
+
+
+// The class is thread-safe with respect to all the provided static methods,
+// as well as HeapLeakChecker objects: they can be accessed by multiple threads.
+class PERFTOOLS_DLL_DECL HeapLeakChecker {
+ public:
+
+  // ----------------------------------------------------------------------- //
+  // Static functions for working with (whole-program) leak checking.
+
+  // If heap leak checking is currently active in some mode
+  // e.g. if leak checking was started (and is still active now)
+  // due to HEAPCHECK=... defined in the environment.
+  // The return value reflects iff HeapLeakChecker objects manually
+  // constructed right now will be doing leak checking or nothing.
+  // Note that we can go from active to inactive state during InitGoogle()
+  // if FLAGS_heap_check gets set to "" by some code before/during InitGoogle().
+  static bool IsActive();
+
+  // Return pointer to the whole-program checker if it has been created
+  // and NULL otherwise.
+  // Once GlobalChecker() returns non-NULL that object will not disappear and
+  // will be returned by all later GlobalChecker calls.
+  // This is mainly to access BytesLeaked() and ObjectsLeaked() (see below)
+  // for the whole-program checker after one calls NoGlobalLeaks()
+  // or similar and gets false.
+  static HeapLeakChecker* GlobalChecker();
+
+  // Do whole-program leak check now (if it was activated for this binary);
+  // return false only if it was activated and has failed.
+  // The mode of the check is controlled by the command-line flags.
+  // This method can be called repeatedly.
+  // Things like GlobalChecker()->SameHeap() can also be called explicitly
+  // to do the desired flavor of the check.
+  static bool NoGlobalLeaks();
+
+  // If whole-program checker if active,
+  // cancel its automatic execution after main() exits.
+  // This requires that some leak check (e.g. NoGlobalLeaks())
+  // has been called at least once on the whole-program checker.
+  static void CancelGlobalCheck();
+
+  // ----------------------------------------------------------------------- //
+  // Non-static functions for starting and doing leak checking.
+
+  // Start checking and name the leak check performed.
+  // The name is used in naming dumped profiles
+  // and needs to be unique only within your binary.
+  // It must also be a string that can be a part of a file name,
+  // in particular not contain path expressions.
+  explicit HeapLeakChecker(const char *name);
+
+  // Destructor (verifies that some *NoLeaks or *SameHeap method
+  // has been called at least once).
+  ~HeapLeakChecker();
+
+  // These used to be different but are all the same now: they return
+  // true iff all memory allocated since this HeapLeakChecker object
+  // was constructor is still reachable from global state.
+  //
+  // Because we fork to convert addresses to symbol-names, and forking
+  // is not thread-safe, and we may be called in a threaded context,
+  // we do not try to symbolize addresses when called manually.
+  bool NoLeaks() { return DoNoLeaks(DO_NOT_SYMBOLIZE); }
+
+  // These forms are obsolete; use NoLeaks() instead.
+  // TODO(csilvers): mark with ATTRIBUTE_DEPRECATED.
+  bool QuickNoLeaks()  { return NoLeaks(); }
+  bool BriefNoLeaks()  { return NoLeaks(); }
+  bool SameHeap()      { return NoLeaks(); }
+  bool QuickSameHeap() { return NoLeaks(); }
+  bool BriefSameHeap() { return NoLeaks(); }
+
+  // Detailed information about the number of leaked bytes and objects
+  // (both of these can be negative as well).
+  // These are available only after a *SameHeap or *NoLeaks
+  // method has been called.
+  // Note that it's possible for both of these to be zero
+  // while SameHeap() or NoLeaks() returned false in case
+  // of a heap state change that is significant
+  // but preserves the byte and object counts.
+  ssize_t BytesLeaked() const;
+  ssize_t ObjectsLeaked() const;
+
+  // ----------------------------------------------------------------------- //
+  // Static helpers to make us ignore certain leaks.
+
+  // Scoped helper class.  Should be allocated on the stack inside a
+  // block of code.  Any heap allocations done in the code block
+  // covered by the scoped object (including in nested function calls
+  // done by the code block) will not be reported as leaks.  This is
+  // the recommended replacement for the GetDisableChecksStart() and
+  // DisableChecksToHereFrom() routines below.
+  //
+  // Example:
+  //   void Foo() {
+  //     HeapLeakChecker::Disabler disabler;
+  //     ... code that allocates objects whose leaks should be ignored ...
+  //   }
+  //
+  // REQUIRES: Destructor runs in same thread as constructor
+  class Disabler {
+   public:
+    Disabler();
+    ~Disabler();
+   private:
+    Disabler(const Disabler&);        // disallow copy
+    void operator=(const Disabler&);  // and assign
+  };
+
+  // Ignore an object located at 'ptr' (can go at the start or into the object)
+  // as well as all heap objects (transitively) referenced from it
+  // for the purposes of heap leak checking.
+  // If 'ptr' does not point to an active allocated object
+  // at the time of this call, it is ignored;
+  // but if it does, the object must not get deleted from the heap later on;
+  // it must also be not already ignored at the time of this call.
+  //
+  // See also HiddenPointer, below, if you need to prevent a pointer from
+  // being traversed by the heap checker but do not wish to transitively
+  // whitelist objects referenced through it.
+  static void IgnoreObject(const void* ptr);
+
+  // Undo what an earlier IgnoreObject() call promised and asked to do.
+  // At the time of this call 'ptr' must point at or inside of an active
+  // allocated object which was previously registered with IgnoreObject().
+  static void UnIgnoreObject(const void* ptr);
+
+  // ----------------------------------------------------------------------- //
+  // Initialization; to be called from main() only.
+
+  // Full starting of recommended whole-program checking.
+  static void InternalInitStart();
+
+  // ----------------------------------------------------------------------- //
+  // Internal types defined in .cc
+
+  class Allocator;
+  struct RangeValue;
+
+ private:
+
+  // ----------------------------------------------------------------------- //
+  // Various helpers
+
+  // Create the name of the heap profile file.
+  // Should be deleted via Allocator::Free().
+  char* MakeProfileNameLocked();
+
+  // Helper for constructors
+  void Create(const char *name, bool make_start_snapshot);
+
+  enum ShouldSymbolize { SYMBOLIZE, DO_NOT_SYMBOLIZE };
+
+  // Helper for *NoLeaks and *SameHeap
+  bool DoNoLeaks(ShouldSymbolize should_symbolize);
+
+  // These used to be public, but they are now deprecated.
+  // Will remove entirely when all internal uses are fixed.
+  // In the meantime, use friendship so the unittest can still test them.
+  static void* GetDisableChecksStart();
+  static void DisableChecksToHereFrom(const void* start_address);
+  static void DisableChecksIn(const char* pattern);
+  friend void RangeDisabledLeaks();
+  friend void NamedTwoDisabledLeaks();
+  friend void* RunNamedDisabledLeaks(void*);
+  friend void TestHeapLeakCheckerNamedDisabling();
+  friend int main(int, char**);
+
+
+  // Helper for DisableChecksIn
+  static void DisableChecksInLocked(const char* pattern);
+
+  // Disable checks based on stack trace entry at a depth <=
+  // max_depth.  Used to hide allocations done inside some special
+  // libraries.
+  static void DisableChecksFromToLocked(const void* start_address,
+                                        const void* end_address,
+                                        int max_depth);
+
+  // Helper for DoNoLeaks to ignore all objects reachable from all live data
+  static void IgnoreAllLiveObjectsLocked(const void* self_stack_top);
+
+  // Callback we pass to ListAllProcessThreads (see thread_lister.h)
+  // that is invoked when all threads of our process are found and stopped.
+  // The call back does the things needed to ignore live data reachable from
+  // thread stacks and registers for all our threads
+  // as well as do other global-live-data ignoring
+  // (via IgnoreNonThreadLiveObjectsLocked)
+  // during the quiet state of all threads being stopped.
+  // For the argument meaning see the comment by ListAllProcessThreads.
+  // Here we only use num_threads and thread_pids, that ListAllProcessThreads
+  // fills for us with the number and pids of all the threads of our process
+  // it found and attached to.
+  static int IgnoreLiveThreadsLocked(void* parameter,
+                                     int num_threads,
+                                     pid_t* thread_pids,
+                                     va_list ap);
+
+  // Helper for IgnoreAllLiveObjectsLocked and IgnoreLiveThreadsLocked
+  // that we prefer to execute from IgnoreLiveThreadsLocked
+  // while all threads are stopped.
+  // This helper does live object discovery and ignoring
+  // for all objects that are reachable from everything
+  // not related to thread stacks and registers.
+  static void IgnoreNonThreadLiveObjectsLocked();
+
+  // Helper for IgnoreNonThreadLiveObjectsLocked and IgnoreLiveThreadsLocked
+  // to discover and ignore all heap objects
+  // reachable from currently considered live objects
+  // (live_objects static global variable in out .cc file).
+  // "name", "name2" are two strings that we print one after another
+  // in a debug message to describe what kind of live object sources
+  // are being used.
+  static void IgnoreLiveObjectsLocked(const char* name, const char* name2);
+
+  // Runs REGISTER_HEAPCHECK_CLEANUP cleanups and potentially
+  // calls DoMainHeapCheck
+  static void RunHeapCleanups();
+
+  // Do the overall whole-program heap leak check if needed;
+  // returns true when did the leak check.
+  static bool DoMainHeapCheck();
+
+  // Type of task for UseProcMapsLocked
+  enum ProcMapsTask {
+    RECORD_GLOBAL_DATA,
+    DISABLE_LIBRARY_ALLOCS
+  };
+
+  // Success/Error Return codes for UseProcMapsLocked.
+  enum ProcMapsResult {
+    PROC_MAPS_USED,
+    CANT_OPEN_PROC_MAPS,
+    NO_SHARED_LIBS_IN_PROC_MAPS
+  };
+
+  // Read /proc/self/maps, parse it, and do the 'proc_maps_task' for each line.
+  static ProcMapsResult UseProcMapsLocked(ProcMapsTask proc_maps_task);
+
+  // A ProcMapsTask to disable allocations from 'library'
+  // that is mapped to [start_address..end_address)
+  // (only if library is a certain system library).
+  static void DisableLibraryAllocsLocked(const char* library,
+                                         uintptr_t start_address,
+                                         uintptr_t end_address);
+
+  // Return true iff "*ptr" points to a heap object
+  // ("*ptr" can point at the start or inside of a heap object
+  //  so that this works e.g. for pointers to C++ arrays, C++ strings,
+  //  multiple-inherited objects, or pointers to members).
+  // We also fill *object_size for this object then
+  // and we move "*ptr" to point to the very start of the heap object.
+  static inline bool HaveOnHeapLocked(const void** ptr, size_t* object_size);
+
+  // Helper to shutdown heap leak checker when it's not needed
+  // or can't function properly.
+  static void TurnItselfOffLocked();
+
+  // Internally-used c-tor to start whole-executable checking.
+  HeapLeakChecker();
+
+  // ----------------------------------------------------------------------- //
+  // Friends and externally accessed helpers.
+
+  // Helper for VerifyHeapProfileTableStackGet in the unittest
+  // to get the recorded allocation caller for ptr,
+  // which must be a heap object.
+  static const void* GetAllocCaller(void* ptr);
+  friend void VerifyHeapProfileTableStackGet();
+
+  // This gets to execute before constructors for all global objects
+  static void BeforeConstructorsLocked();
+  friend void HeapLeakChecker_BeforeConstructors();
+
+  // This gets to execute after destructors for all global objects
+  friend void HeapLeakChecker_AfterDestructors();
+
+  // ----------------------------------------------------------------------- //
+  // Member data.
+
+  class SpinLock* lock_;  // to make HeapLeakChecker objects thread-safe
+  const char* name_;  // our remembered name (we own it)
+                      // NULL means this leak checker is a noop
+
+  // Snapshot taken when the checker was created.  May be NULL
+  // for the global heap checker object.  We use void* instead of
+  // HeapProfileTable::Snapshot* to avoid including heap-profile-table.h.
+  void* start_snapshot_;
+
+  bool has_checked_;  // if we have done the leak check, so these are ready:
+  ssize_t inuse_bytes_increase_;  // bytes-in-use increase for this checker
+  ssize_t inuse_allocs_increase_;  // allocations-in-use increase
+                                   // for this checker
+  bool keep_profiles_;  // iff we should keep the heap profiles we've made
+
+  // ----------------------------------------------------------------------- //
+
+  // Disallow "evil" constructors.
+  HeapLeakChecker(const HeapLeakChecker&);
+  void operator=(const HeapLeakChecker&);
+};
+
+
+// Holds a pointer that will not be traversed by the heap checker.
+// Contrast with HeapLeakChecker::IgnoreObject(o), in which o and
+// all objects reachable from o are ignored by the heap checker.
+template <class T>
+class HiddenPointer {
+ public:
+  explicit HiddenPointer(T* t)
+      : masked_t_(reinterpret_cast<uintptr_t>(t) ^ kHideMask) {
+  }
+  // Returns unhidden pointer.  Be careful where you save the result.
+  T* get() const { return reinterpret_cast<T*>(masked_t_ ^ kHideMask); }
+
+ private:
+  // Arbitrary value, but not such that xor'ing with it is likely
+  // to map one valid pointer to another valid pointer:
+  static const uintptr_t kHideMask =
+      static_cast<uintptr_t>(0xF03A5F7BF03A5F7Bll);
+  uintptr_t masked_t_;
+};
+
+// A class that exists solely to run its destructor.  This class should not be
+// used directly, but instead by the REGISTER_HEAPCHECK_CLEANUP macro below.
+class PERFTOOLS_DLL_DECL HeapCleaner {
+ public:
+  typedef void (*void_function)(void);
+  HeapCleaner(void_function f);
+  static void RunHeapCleanups();
+ private:
+  static std::vector<void_function>* heap_cleanups_;
+};
+
+// A macro to declare module heap check cleanup tasks
+// (they run only if we are doing heap leak checking.)
+// 'body' should be the cleanup code to run.  'name' doesn't matter,
+// but must be unique amongst all REGISTER_HEAPCHECK_CLEANUP calls.
+#define REGISTER_HEAPCHECK_CLEANUP(name, body)  \
+  namespace { \
+  void heapcheck_cleanup_##name() { body; } \
+  static HeapCleaner heapcheck_cleaner_##name(&heapcheck_cleanup_##name); \
+  }
+
+#endif  // BASE_HEAP_CHECKER_H_