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1 //===- LeaksContext.h - LeadDetector Implementation ------------*- C++ -*--===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defines various helper methods and classes used by
11 // LLVMContextImpl for leaks detectors.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/Value.h"
16 #include "llvm/ADT/SmallPtrSet.h"
17 
18 namespace llvm {
19 
20 template <class T>
21 struct PrinterTrait {
printPrinterTrait22   static void print(const T* P) { errs() << P; }
23 };
24 
25 template<>
26 struct PrinterTrait<Value> {
27   static void print(const Value* P) { errs() << *P; }
28 };
29 
30 template <typename T>
31 struct LeakDetectorImpl {
32   explicit LeakDetectorImpl(const char* const name = "") :
33     Cache(0), Name(name) { }
34 
35   void clear() {
36     Cache = 0;
37     Ts.clear();
38   }
39 
40   void setName(const char* n) {
41     Name = n;
42   }
43 
44   // Because the most common usage pattern, by far, is to add a
45   // garbage object, then remove it immediately, we optimize this
46   // case.  When an object is added, it is not added to the set
47   // immediately, it is added to the CachedValue Value.  If it is
48   // immediately removed, no set search need be performed.
49   void addGarbage(const T* o) {
50     assert(Ts.count(o) == 0 && "Object already in set!");
51     if (Cache) {
52       assert(Cache != o && "Object already in set!");
53       Ts.insert(Cache);
54     }
55     Cache = o;
56   }
57 
58   void removeGarbage(const T* o) {
59     if (o == Cache)
60       Cache = 0; // Cache hit
61     else
62       Ts.erase(o);
63   }
64 
65   bool hasGarbage(const std::string& Message) {
66     addGarbage(0); // Flush the Cache
67 
68     assert(Cache == 0 && "No value should be cached anymore!");
69 
70     if (!Ts.empty()) {
71       errs() << "Leaked " << Name << " objects found: " << Message << ":\n";
72       for (typename SmallPtrSet<const T*, 8>::iterator I = Ts.begin(),
73            E = Ts.end(); I != E; ++I) {
74         errs() << '\t';
75         PrinterTrait<T>::print(*I);
76         errs() << '\n';
77       }
78       errs() << '\n';
79 
80       return true;
81     }
82 
83     return false;
84   }
85 
86 private:
87   SmallPtrSet<const T*, 8> Ts;
88   const T* Cache;
89   const char* Name;
90 };
91 
92 }
93