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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 #ifndef LLVM_IR_LEAKSCONTEXT_H
     16 #define LLVM_IR_LEAKSCONTEXT_H
     17 
     18 #include "llvm/ADT/SmallPtrSet.h"
     19 #include "llvm/IR/Value.h"
     20 #include "llvm/Support/raw_ostream.h"
     21 
     22 namespace llvm {
     23 
     24 template <class T>
     25 struct PrinterTrait {
     26   static void print(const T* P) { errs() << P; }
     27 };
     28 
     29 template<>
     30 struct PrinterTrait<Value> {
     31   static void print(const Value* P) { errs() << *P; }
     32 };
     33 
     34 template <typename T>
     35 struct LeakDetectorImpl {
     36   explicit LeakDetectorImpl(const char* const name = "") :
     37     Cache(nullptr), Name(name) { }
     38 
     39   void clear() {
     40     Cache = nullptr;
     41     Ts.clear();
     42   }
     43 
     44   void setName(const char* n) {
     45     Name = n;
     46   }
     47 
     48   // Because the most common usage pattern, by far, is to add a
     49   // garbage object, then remove it immediately, we optimize this
     50   // case.  When an object is added, it is not added to the set
     51   // immediately, it is added to the CachedValue Value.  If it is
     52   // immediately removed, no set search need be performed.
     53   void addGarbage(const T* o) {
     54     assert(Ts.count(o) == 0 && "Object already in set!");
     55     if (Cache) {
     56       assert(Cache != o && "Object already in set!");
     57       Ts.insert(Cache);
     58     }
     59     Cache = o;
     60   }
     61 
     62   void removeGarbage(const T* o) {
     63     if (o == Cache)
     64       Cache = nullptr; // Cache hit
     65     else
     66       Ts.erase(o);
     67   }
     68 
     69   bool hasGarbage(const std::string& Message) {
     70     addGarbage(nullptr); // Flush the Cache
     71 
     72     assert(!Cache && "No value should be cached anymore!");
     73 
     74     if (!Ts.empty()) {
     75       errs() << "Leaked " << Name << " objects found: " << Message << ":\n";
     76       for (typename SmallPtrSet<const T*, 8>::iterator I = Ts.begin(),
     77            E = Ts.end(); I != E; ++I) {
     78         errs() << '\t';
     79         PrinterTrait<T>::print(*I);
     80         errs() << '\n';
     81       }
     82       errs() << '\n';
     83 
     84       return true;
     85     }
     86 
     87     return false;
     88   }
     89 
     90 private:
     91   SmallPtrSet<const T*, 8> Ts;
     92   const T* Cache;
     93   const char* Name;
     94 };
     95 
     96 }
     97 
     98 #endif // LLVM_IR_LEAKSCONTEXT_H
     99