VC环境下检查内存泄漏memory leak的方法

通过改写delete new方法，我们可以记录内存分配的地址，数量。因此，也就可以知道哪此内存在程序结束后没有释放。

将如下代码改存放为trace.cpp ，将trace.cpp放入要检测的工程。运行Debug调试程序，在Debug的输出里会有提示信息。

/**********************************************************************
Trace alloc
-----------
Purpose:

  Implement a allocation check routine that reports the whole
  callstack for each leaked allocation.

  Based on the code for ExtendedTrace written by
  Zoltan Csizmadia, zoltan_csizmadia@yahoo.com.

Author:

  Erik Rydgren, erik@rydgrens.net.
 
Usage:
  1/ Define DETECT_LEAKS in the project settings under
     C++/preprocessor.

     If you want checking of overwrites then define DETECT_OVERWRITES
     in the project settings. Change the frequency of the checks by
     altering the NML_CHECK_EVERY define in tracealloc.cpp.
 
  2/ Compile.
 
     If you get multiple defined symbols (overloaded new and delete)
     add linker switch /FORCE:MULTIPLE on the exe and make sure the
     tracealloc new and delete is the ones used. If not, reorder the
     included libraries until they do.

**********************************************************************/

#if defined(_DEBUG) && defined(WIN32) //&& defined(DETECT_LEAKS)

#include <windows.h>
#include <tchar.h>
#include <iostream>
#include <ImageHlp.h>
#include <string>
#include <assert.h>

using namespace std;

typedef std::basic_string<TCHAR, char_traits<TCHAR> > tcstring;

// Setup how much buffer is used for a single path fetch, increase if you get AV's during leak dump (4096 is plenty though)
#define BUFFERSIZE 4096

// Define how many levels of callstack that should be fetched for each allocation.
// Each level costs 2*sizof(ULONG) bytes / allocation.
#define MAXSTACK 5

// Define size of no mans land
#define NO_MANS_LAND_SIZE 16

// Define frequency of no mans land checking
#define NML_CHECK_EVERY 1000

#pragma comment( lib, "imagehlp.lib" )

void GetStackTrace(HANDLE hThread, ULONG ranOffsets[][2], ULONG nMaxStack );
void WriteStackTrace(ULONG ranOffsets[][2], ULONG nMaxStack, tcstring& roOut);
void* TraceAlloc(size_t nSize);
void TraceDealloc(void* poMem);

void OutputDebugStringFormat( LPCTSTR lpszFormat, ... )
{
 TCHAR    lpszBuffer[BUFFERSIZE];
 va_list  fmtList;

 va_start( fmtList, lpszFormat );
 _vstprintf( lpszBuffer, lpszFormat, fmtList );
 va_end( fmtList );

   ::OutputDebugString( lpszBuffer );
}

// Unicode safe char* -> TCHAR* conversion
void PCSTR2LPTSTR( PCSTR lpszIn, LPTSTR lpszOut )
{
#if defined(UNICODE)||defined(_UNICODE)
   ULONG index = 0;
   PCSTR lpAct = lpszIn;
  
 for( ; ; lpAct++ )
 {
  lpszOut[index++] = (TCHAR)(*lpAct);
  if ( *lpAct == 0 )
   break;
 }
#else
   // This is trivial :)
 strcpy( lpszOut, lpszIn );
#endif
}

// Let's figure out the path for the symbol files
// Search path= ".;%_NT_SYMBOL_PATH%;%_NT_ALTERNATE_SYMBOL_PATH%;%SYSTEMROOT%;%SYSTEMROOT%/System32;" + lpszIniPath
// Note: There is no size check for lpszSymbolPath!
void InitSymbolPath( PSTR lpszSymbolPath, PCSTR lpszIniPath )
{
 CHAR lpszPath[BUFFERSIZE];

   // Creating the default path
   // ".;%_NT_SYMBOL_PATH%;%_NT_ALTERNATE_SYMBOL_PATH%;%SYSTEMROOT%;%SYSTEMROOT%/System32;"
 strcpy( lpszSymbolPath, "." );

 // environment variable _NT_SYMBOL_PATH
 if ( GetEnvironmentVariableA( "_NT_SYMBOL_PATH", lpszPath, BUFFERSIZE ) )
 {
    strcat( lpszSymbolPath, ";" );
  strcat( lpszSymbolPath, lpszPath );
 }

 // environment variable _NT_ALTERNATE_SYMBOL_PATH
 if ( GetEnvironmentVariableA( "_NT_ALTERNATE_SYMBOL_PATH", lpszPath, BUFFERSIZE ) )
 {
    strcat( lpszSymbolPath, ";" );
  strcat( lpszSymbolPath, lpszPath );
 }

 // environment variable SYSTEMROOT
 if ( GetEnvironmentVariableA( "SYSTEMROOT", lpszPath, BUFFERSIZE ) )
 {
    strcat( lpszSymbolPath, ";" );
  strcat( lpszSymbolPath, lpszPath );
  strcat( lpszSymbolPath, ";" );

  // SYSTEMROOT/System32
  strcat( lpszSymbolPath, lpszPath );
  strcat( lpszSymbolPath, "//System32" );
 }

   // Add user defined path
 if ( lpszIniPath != NULL )
  if ( lpszIniPath[0] != '/0' )
  {
     strcat( lpszSymbolPath, ";" );
   strcat( lpszSymbolPath, lpszIniPath );
  }
}

// Uninitialize the loaded symbol files
BOOL UninitSymInfo()
{
 return SymCleanup( GetCurrentProcess() );
}

// Initializes the symbol files
BOOL InitSymInfo( PCSTR lpszInitialSymbolPath )
{
 CHAR     lpszSymbolPath[BUFFERSIZE];
   DWORD    symOptions = SymGetOptions();

 symOptions |= SYMOPT_LOAD_LINES;
 symOptions &= ~SYMOPT_UNDNAME;
 SymSetOptions( symOptions );

   // Get the search path for the symbol files
 InitSymbolPath( lpszSymbolPath, lpszInitialSymbolPath );

 return SymInitialize( GetCurrentProcess(), lpszSymbolPath, TRUE);
}

// Get the module name from a given address
BOOL GetModuleNameFromAddress( UINT address, LPTSTR lpszModule )
{
 BOOL              ret = FALSE;
 IMAGEHLP_MODULE   moduleInfo;

 ::ZeroMemory( &moduleInfo, sizeof(moduleInfo) );
 moduleInfo.SizeOfStruct = sizeof(moduleInfo);

 if ( SymGetModuleInfo( GetCurrentProcess(), (DWORD)address, &moduleInfo ) )
 {
    // Got it!
  PCSTR2LPTSTR( moduleInfo.ModuleName, lpszModule );
  ret = TRUE;
 }
 else
    // Not found :(
  _tcscpy( lpszModule, _T("?") );
 
 return ret;
}

// Get function prototype and parameter info from ip address and stack address
BOOL GetFunctionInfoFromAddresses( ULONG fnAddress, ULONG stackAddress, LPTSTR lpszSymbol )
{
 BOOL              ret = FALSE;
 DWORD             dwDisp = 0;
 DWORD             dwSymSize = 10000;
   TCHAR             lpszUnDSymbol[BUFFERSIZE]=_T("?");
 CHAR              lpszNonUnicodeUnDSymbol[BUFFERSIZE]="?";
 LPTSTR            lpszParamSep = NULL;
 LPCTSTR           lpszParsed = lpszUnDSymbol;
 PIMAGEHLP_SYMBOL  pSym = (PIMAGEHLP_SYMBOL)GlobalAlloc( GMEM_FIXED, dwSymSize );

 ::ZeroMemory( pSym, dwSymSize );
 pSym->SizeOfStruct = dwSymSize;
 pSym->MaxNameLength = dwSymSize - sizeof(IMAGEHLP_SYMBOL);

   // Set the default to unknown
 _tcscpy( lpszSymbol, _T("?") );

 // Get symbol info for IP
 if ( SymGetSymFromAddr( GetCurrentProcess(), (ULONG)fnAddress, &dwDisp, pSym ) )
 {
    // Make the symbol readable for humans
  UnDecorateSymbolName( pSym->Name, lpszNonUnicodeUnDSymbol, BUFFERSIZE,
   UNDNAME_COMPLETE |
   UNDNAME_NO_THISTYPE |
   UNDNAME_NO_SPECIAL_SYMS |
   UNDNAME_NO_MEMBER_TYPE |
   UNDNAME_NO_MS_KEYWORDS |
   UNDNAME_NO_ACCESS_SPECIFIERS );

      // Symbol information is ANSI string
  PCSTR2LPTSTR( lpszNonUnicodeUnDSymbol, lpszUnDSymbol );

      // I am just smarter than the symbol file :)
  if ( _tcscmp(lpszUnDSymbol, _T("_WinMain@16")) == 0 )
   _tcscpy(lpszUnDSymbol, _T("WinMain(HINSTANCE,HINSTANCE,LPCTSTR,int)"));
  else
  if ( _tcscmp(lpszUnDSymbol, _T("_main")) == 0 )
   _tcscpy(lpszUnDSymbol, _T("main(int,TCHAR * *)"));
  else
  if ( _tcscmp(lpszUnDSymbol, _T("_mainCRTStartup")) == 0 )
   _tcscpy(lpszUnDSymbol, _T("mainCRTStartup()"));
  else
  if ( _tcscmp(lpszUnDSymbol, _T("_wmain")) == 0 )
   _tcscpy(lpszUnDSymbol, _T("wmain(int,TCHAR * *,TCHAR * *)"));
  else
  if ( _tcscmp(lpszUnDSymbol, _T("_wmainCRTStartup")) == 0 )
   _tcscpy(lpszUnDSymbol, _T("wmainCRTStartup()"));

  lpszSymbol[0] = _T('/0');

      // Let's go through the stack, and modify the function prototype, and insert the actual
      // parameter values from the stack
  if ( _tcsstr( lpszUnDSymbol, _T("(void)") ) == NULL && _tcsstr( lpszUnDSymbol, _T("()") ) == NULL)
  {
   ULONG index = 0;
   for( ; ; index++ )
   {
    lpszParamSep = _tcschr( lpszParsed, _T(',') );
    if ( lpszParamSep == NULL )
     break;

    *lpszParamSep = _T('/0');

    _tcscat( lpszSymbol, lpszParsed );
    _stprintf( lpszSymbol + _tcslen(lpszSymbol), _T("=0x%08X,"), *((ULONG*)(stackAddress) + 2 + index) );

    lpszParsed = lpszParamSep + 1;
   }

   lpszParamSep = _tcschr( lpszParsed, _T(')') );
   if ( lpszParamSep != NULL )
   {
    *lpszParamSep = _T('/0');

    _tcscat( lpszSymbol, lpszParsed );
    _stprintf( lpszSymbol + _tcslen(lpszSymbol), _T("=0x%08X)"), *((ULONG*)(stackAddress) + 2 + index) );

    lpszParsed = lpszParamSep + 1;
   }
  }

  _tcscat( lpszSymbol, lpszParsed );
  
  ret = TRUE;
 }

 GlobalFree( pSym );

 return ret;
}

// Get source file name and line number from IP address
// The output format is: "sourcefile(linenumber)" or
//                       "modulename!address" or
//                       "address"
BOOL GetSourceInfoFromAddress( UINT address, LPTSTR lpszSourceInfo )
{
 BOOL           ret = FALSE;
 IMAGEHLP_LINE  lineInfo;
 DWORD          dwDisp;
 TCHAR          lpszFileName[BUFFERSIZE] = _T("");
 TCHAR          lpModuleInfo[BUFFERSIZE] = _T("");

 _tcscpy( lpszSourceInfo, _T("?(?)") );

 ::ZeroMemory( &lineInfo, sizeof( lineInfo ) );
 lineInfo.SizeOfStruct = sizeof( lineInfo );

 if ( SymGetLineFromAddr( GetCurrentProcess(), address, &dwDisp, &lineInfo ) )
 {
    // Got it. Let's use "sourcefile(linenumber)" format
  PCSTR2LPTSTR( lineInfo.FileName, lpszFileName );
  _stprintf( lpszSourceInfo, _T("%s(%d)"), lpszFileName, lineInfo.LineNumber );
  ret = TRUE;
 }
 else
 {
      // There is no source file information. :(
      // Let's use the "modulename!address" format
    GetModuleNameFromAddress( address, lpModuleInfo );

  if ( lpModuleInfo[0] == _T('?') || lpModuleInfo[0] == _T('/0'))
     // There is no modulename information. :((
         // Let's use the "address" format
   _stprintf( lpszSourceInfo, _T("0x%08X"), lpModuleInfo, address );
  else
   _stprintf( lpszSourceInfo, _T("%s!0x%08X"), lpModuleInfo, address );

  ret = FALSE;
 }
 
 return ret;
}

void GetStackTrace(HANDLE hThread, ULONG ranOffsets[][2], ULONG nMaxStack )
{
 STACKFRAME     callStack;
 BOOL           bResult;
 CONTEXT        context;
 TCHAR          symInfo[BUFFERSIZE] = _T("?");
 TCHAR          srcInfo[BUFFERSIZE] = _T("?");
 HANDLE         hProcess = GetCurrentProcess();

   // If it's not this thread, let's suspend it, and resume it at the end
 if ( hThread != GetCurrentThread() )
  if ( SuspendThread( hThread ) == -1 )
  {
     // whaaat ?!
     OutputDebugStringFormat( _T("Call stack info(thread=0x%X) failed./n") );
   return;
  }

 ::ZeroMemory( &context, sizeof(context) );
 context.ContextFlags = CONTEXT_FULL;

 if ( !GetThreadContext( hThread, &context ) )
 {
      OutputDebugStringFormat( _T("Call stack info(thread=0x%X) failed./n") );
    return;
 }
 
 ::ZeroMemory( &callStack, sizeof(callStack) );
 callStack.AddrPC.Offset    = context.Eip;
 callStack.AddrStack.Offset = context.Esp;
 callStack.AddrFrame.Offset = context.Ebp;
 callStack.AddrPC.Mode      = AddrModeFlat;
 callStack.AddrStack.Mode   = AddrModeFlat;
 callStack.AddrFrame.Mode   = AddrModeFlat;

 for( ULONG index = 0; ; index++ )
 {
  bResult = StackWalk(
   IMAGE_FILE_MACHINE_I386,
   hProcess,
   hThread,
       &callStack,
   NULL,
   NULL,
   SymFunctionTableAccess,
   SymGetModuleBase,
   NULL);

    // Ignore the first two levels (it's only TraceAlloc and operator new anyhow)
  if ( index < 3 )
     continue;

    // Break if we have fetched nMaxStack levels
    if ( index-3 == nMaxStack)
      break;

    // If we are at the top of the stackframe then break.
  if( !bResult || callStack.AddrFrame.Offset == 0) {
      ranOffsets[index-3][0] = 0;
      ranOffsets[index-3][1] = 0;
   break;
    }
     
    // Remember program counter and frame pointer
    ranOffsets[index-3][0] = callStack.AddrPC.Offset;
    ranOffsets[index-3][1] = callStack.AddrFrame.Offset;
 }

 if ( hThread != GetCurrentThread() )
  ResumeThread( hThread );
}

void WriteStackTrace(ULONG ranOffsets[][2], ULONG nMaxStack, tcstring& roOut)
{
 TCHAR          symInfo[BUFFERSIZE] = _T("?");
 TCHAR          srcInfo[BUFFERSIZE] = _T("?");

  for (ULONG index = 0; index < nMaxStack && ranOffsets[index][0] != 0 && ranOffsets[index][1] != 0; index++) {
   GetFunctionInfoFromAddresses( ranOffsets[index][0], ranOffsets[index][1], symInfo );
   GetSourceInfoFromAddress( ranOffsets[index][0], srcInfo );

    roOut += _T("     ");
    roOut += srcInfo;
    roOut += _T(" : ");
    roOut += symInfo;
    roOut += _T("/n");
  }
}

struct sdAllocBlock {
  unsigned long nMagicNumber;
  sdAllocBlock* poNext;
  sdAllocBlock* poPrev;
  size_t nSize;
  ULONG anStack[MAXSTACK][2];
  char pzNoMansLand[NO_MANS_LAND_SIZE];

  sdAllocBlock()
  {
    Init();
  }

  void Init() {
    poNext = this;
    poPrev = this;
    nMagicNumber = 0x55555555;
  }

  void Disconnect() {
    if (poNext != this) {
      poNext->poPrev = poPrev;
      poPrev->poNext = poNext;
      poNext = this;
      poPrev = this;
    }
  }

  void ConnectTo(sdAllocBlock* poPos) {
    Disconnect();
    poPrev = poPos;
    poNext = poPos->poNext;
    poPos->poNext->poPrev = this;
    poPos->poNext = this;
  }
};

void LeakDump(tcstring& roOut);

class CS {
  CRITICAL_SECTION cs;
public:
  CS() { InitializeCriticalSection(&cs); }
  ~CS() { }
  operator CRITICAL_SECTION& () { return cs; }
};

class Guard {
  CRITICAL_SECTION& rcs;
public:
  Guard(CRITICAL_SECTION& rcs)
  : rcs(rcs) { EnterCriticalSection(&rcs); }
  ~Guard() { LeaveCriticalSection(&rcs); }
};

class cLeakDetector
{
public:

  cLeakDetector() {
    InitSymInfo(NULL);
  }
 
  ~cLeakDetector() {   
    tcstring leaks;   
    LeakDump(leaks);   
    OutputDebugString(leaks.c_str());   
    UninitSymInfo(); 
  }
};

static unsigned int nNumAllocs = 0;
static unsigned int nCurrentAllocs = 0;
static unsigned int nMaxConcurrent = 0;

CS& Gate() {
  static CS cs;
  return cs;
}

sdAllocBlock& Head()
{
  static cLeakDetector oDetector;
  static sdAllocBlock oHead;
  return oHead;
}

class cInitializer {
  public: cInitializer() { Head(); };
} oInitalizer;

void LeakDump(tcstring& roOut)
{
  Guard at(Gate());
 
  TCHAR buffer[65];

  sdAllocBlock* poBlock = Head().poNext;
  while (poBlock != &Head()) {
    tcstring stack;
    WriteStackTrace(poBlock->anStack, MAXSTACK, stack);

    bool bIsKnownLeak = false;

    // afxMap leaks is MFC. Not ours.
    if (stack.find(_T(": afxMap")) != tcstring::npos)
      bIsKnownLeak = true;

    if (!bIsKnownLeak) {
      roOut += _T("Leak of ");
      roOut += _itot(poBlock->nSize, buffer, 10);
      roOut += _T(" bytes detected:/n");
      roOut += stack;
      roOut += _T("/n");
    }

    poBlock = poBlock->poNext;
  }

  roOut += _T("Memory statistics/n-----------------/n");
  roOut += _T("Total allocations: ");
  roOut += _itot(nNumAllocs, buffer, 10);
  roOut += _T("/n");
  roOut += _T("Max concurrent allocations: ");
  roOut += _itot(nMaxConcurrent, buffer, 10);
  roOut += _T("/n");
}

bool AssertMem(char* m, char c, size_t s)
{
  for (size_t i = 0; i < s; i++)
    if (m[i] != c) break;
  return i >= s;
}

void CheckNoMansLand()
{
  Guard at(Gate());

  sdAllocBlock* poBlock = Head().poNext;
  while (poBlock != &Head()) {
    if (!AssertMem(poBlock->pzNoMansLand, 0x55, NO_MANS_LAND_SIZE)) {
      bool MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_LEAD = false;
      tcstring stack;
      WriteStackTrace(poBlock->anStack, MAXSTACK, stack);
      assert(MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_LEAD);
    }
    char* pzNoMansLand = ((char*)poBlock) + sizeof(sdAllocBlock) + poBlock->nSize;
    if (!AssertMem(pzNoMansLand, 0x55, NO_MANS_LAND_SIZE)) {
      bool MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_TAIL = false;
      tcstring stack;
      WriteStackTrace(poBlock->anStack, MAXSTACK, stack);
      assert(MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_TAIL);
    }
    poBlock = poBlock->poNext;
  }
}

void* TraceAlloc(size_t nSize)
{
  Guard at(Gate());
 
  nNumAllocs++;
#ifdef DETECT_OVERWRITES
  if (nNumAllocs % NML_CHECK_EVERY == 0) {
    CheckNoMansLand();
  }
#endif

  sdAllocBlock* poBlock = (sdAllocBlock*) malloc(nSize + sizeof(sdAllocBlock) + NO_MANS_LAND_SIZE);
  poBlock->Init();
  poBlock->nSize = nSize;
  char* pzNoMansLand = ((char*)poBlock) + sizeof(sdAllocBlock) + poBlock->nSize;
  memset(poBlock->pzNoMansLand, 0x55, NO_MANS_LAND_SIZE);
  memset(pzNoMansLand, 0x55, NO_MANS_LAND_SIZE);

  GetStackTrace(GetCurrentThread(), poBlock->anStack, MAXSTACK );

  poBlock->ConnectTo(&Head());
  nCurrentAllocs++;
  if (nCurrentAllocs > nMaxConcurrent)
    nMaxConcurrent = nCurrentAllocs;
  return (void*)(((char*) poBlock) + sizeof(sdAllocBlock));
}

void TraceDealloc(void* poMem)
{
  Guard at(Gate());

  if (!poMem) return; // delete NULL; = do nothing

  sdAllocBlock* poBlock = (sdAllocBlock*) ((char*)poMem - sizeof(sdAllocBlock));
  char* pzNoMansLand = ((char*)poBlock) + sizeof(sdAllocBlock) + poBlock->nSize;

  if (poBlock->nMagicNumber != 0x55555555) {
    // Whupps, something fishy is going on

    // Validate the address against our list of allocated blocks
    sdAllocBlock* poLoopBlock = Head().poNext;
    while (poLoopBlock != &Head() && poLoopBlock != poBlock)
      poLoopBlock = poLoopBlock->poNext;
    if (poLoopBlock == &Head()) {
      // Hell we didn't allocate this block.
      // Just free the memory and hope for the best.
      free(poMem);
    }
    else {
      bool MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_LEAD = false;
      assert(MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_LEAD);
    }
  } 
  else if (!AssertMem(poBlock->pzNoMansLand, 0x55, NO_MANS_LAND_SIZE)) {
    bool MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_LEAD = false;
    assert(MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_LEAD);
  }
  else if (!AssertMem(pzNoMansLand, 0x55, NO_MANS_LAND_SIZE)) {
    bool MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_TAIL = false;
    assert(MEMORYERROR_STUFF_WRITTEN_IN_NOMANSLAND_TAIL);
  }
  else {
    poBlock->Disconnect();
    free(poBlock);
    nCurrentAllocs--;
  }
}

// Take over global new and delete
void* operator new(size_t s)
{
  return TraceAlloc(s);
}

void* operator new[](size_t s)
{
  return TraceAlloc(s);
}

void operator delete(void* pMem)
{
  TraceDealloc(pMem);
}

void operator delete[] (void* pMem)
{
  TraceDealloc(pMem);
}

// And then some crap for taking over MFC allocations.
void* __cdecl operator new(size_t s, LPCSTR lpszFileName, int nLine)
{
  return TraceAlloc(s);
}

void* __cdecl operator new[](size_t s, LPCSTR lpszFileName, int nLine)
{
  return TraceAlloc(s);
}

void __cdecl operator delete(void* pMem, LPCSTR /* lpszFileName */, int /* nLine */)
{
  TraceDealloc(pMem);
}

void __cdecl operator delete[](void* pMem, LPCSTR /* lpszFileName */, int /* nLine */)
{
  TraceDealloc(pMem);
}

#endif