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29
30// ---
31// All Rights Reserved.
32//
33// Author: Maxim Lifantsev
34//
35// A file to ensure that components of heap leak checker run before
36// all global object constructors and after all global object
37// destructors.
38//
39// This file must be the last library any binary links against.
40// Otherwise, the heap checker may not be able to run early enough to
41// catalog all the global objects in your program.  If this happens,
42// and later in the program you allocate memory and have one of these
43// "uncataloged" global objects point to it, the heap checker will
44// consider that allocation to be a leak, even though it's not (since
45// the allocated object is reachable from global data and hence "live").
46
47#include <gperftools/malloc_extension.h>
48#include "base/abort.h"
49
50// A dummy variable to refer from heap-checker.cc.  This is to make
51// sure this file is not optimized out by the linker.
52bool heap_leak_checker_bcad_variable;
53
54extern void HeapLeakChecker_AfterDestructors();  // in heap-checker.cc
55
56// A helper class to ensure that some components of heap leak checking
57// can happen before construction and after destruction
58// of all global/static objects.
59class HeapLeakCheckerGlobalPrePost {
60 public:
61  HeapLeakCheckerGlobalPrePost() {
62    if (count_ == 0) {
63      // The 'new int' will ensure that we have run an initial malloc
64      // hook, which will set up the heap checker via
65      // MallocHook_InitAtFirstAllocation_HeapLeakChecker.  See malloc_hook.cc.
66      // This is done in this roundabout fashion in order to avoid self-deadlock
67      // if we directly called HeapLeakChecker_BeforeConstructors here.
68      delete new int;
69      // This needs to be called before the first allocation of an STL
70      // object, but after libc is done setting up threads (because it
71      // calls setenv, which requires a thread-aware errno).  By
72      // putting it here, we hope it's the first bit of code executed
73      // after the libc global-constructor code.
74      MallocExtension::Initialize();
75    }
76    ++count_;
77  }
78  ~HeapLeakCheckerGlobalPrePost() {
79    if (count_ <= 0)  tcmalloc::Abort();
80    --count_;
81    if (count_ == 0)  HeapLeakChecker_AfterDestructors();
82  }
83 private:
84  // Counter of constructions/destructions of objects of this class
85  // (just in case there are more than one of them).
86  static int count_;
87};
88
89int HeapLeakCheckerGlobalPrePost::count_ = 0;
90
91// The early-construction/late-destruction global object.
92static const HeapLeakCheckerGlobalPrePost heap_leak_checker_global_pre_post;
93