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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 {
     22   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