如何查找 C++ 中的内存泄漏

在嵌入式环境中检测 C++ 内存泄漏的好方法是什么？我尝试重载 new 运算符来记录每个数据分配，但我一定做错了什么，这种方法不起作用。还有其他人遇到过类似的情况吗？

这是 new 和 delete 运算符重载的代码。

EDIT:

完全披露：我正在寻找程序中的内存泄漏，并且我正在使用其他人编写的代码来重载 new 和 delete 运算符。我的部分问题是我不完全理解它的作用。我知道目标是记录调用者和前一个调用者的地址、分配的大小、如果我们正在分配则为 1、如果我们正在释放则为 2。加上正在运行的线程的名称。

感谢您的所有建议，我将尝试工作中有人建议的不同方法。如果它有效，我会将其发布在这里。

再次感谢所有一流的程序员花时间回答。

StackOverflow 太棒了！

结论

感谢所有的答案。不幸的是，我不得不转向另一个更紧迫的问题。这次泄漏仅发生在极不可能的情况下。我对放弃它感到很糟糕，如果我有更多时间，我可能会再回去。我选择了我最有可能使用的答案。

#include <stdlib.h>
#include "stdio.h"
#include "nucleus.h"
#include "plus/inc/dm_defs.h"
#include "plus/inc/pm_defs.h"

#include "posix\inc\posix.h"

extern void* TCD_Current_Thread;
extern "C" void rd_write_text(char * text);
extern PM_PCB * PMD_Created_Pools_List;

typedef struct {
    void* addr;
    uint16_t size;
    uint16_t flags;
} MemLogEntryNarrow_t;

typedef struct {
    void* addr;
    uint16_t size;
    uint16_t flags;
    void* caller;
    void* prev_caller;
    void* taskid;
    uint32_t timestamp;
} MemLogEntryWide_t;

//size lookup table
unsigned char MEM_bitLookupTable[] = {
 0,1,1,2,1,2,2,3,1,2,2,3,1,3,3,4
};

//#pragma CODE_SECTION ("section_ramset1_0")
void *::operator new(unsigned int size)
{
   asm(" STR R14, [R13, #0xC]");  //save stack address temp[0]
   asm(" STR R13, [R13, #0x10]");  //save pc return address temp[1]

   if ( loggingEnabled )
   {
      uint32_t savedInterruptState;
      uint32_t currentIndex;

      // protect the thread unsafe section.
      savedInterruptState = NU_Local_Control_Interrupts(NU_DISABLE_INTERRUPTS);

      // Note that this code is FRAGILE.  It peeks backwards on the stack to find the return
      // address of the caller.  The location of the return address on the stack can be easily changed
      // as a result of other changes in this function (i.e. adding local variables, etc).
      // The offsets may need to be adjusted if this function is touched.
      volatile unsigned int temp[2];

      unsigned int *addr = (unsigned int *)temp[0] - 1;
      unsigned int count = 1 + (0x20/4);   //current stack space ***

      //Scan for previous store
      while ((*addr & 0xFFFF0000) != 0xE92D0000)
      {
         if ((*addr & 0xFFFFF000) == 0xE24DD000)
         {
            //add offset in words
            count += ((*addr & 0xFFF) >> 2);
         }
         addr--;
      }

      count += MEM_bitLookupTable[*addr & 0xF];
      count += MEM_bitLookupTable[(*addr >>4) & 0xF];
      count += MEM_bitLookupTable[(*addr >> 8) & 0xF];
      count += MEM_bitLookupTable[(*addr >> 12) & 0xF];

      addr = (unsigned int *)temp[1] + count;
      // FRAGILE CODE ENDS HERE

      currentIndex = currentMemLogWriteIndex;
      currentMemLogWriteIndex++;

      if ( memLogNarrow )
      {
         if (currentMemLogWriteIndex >= MEMLOG_SIZE/2 )
         {
            loggingEnabled = false;
            rd_write_text( "Allocation Logging is complete and DISABLED!\r\n\r\n");
         }
         // advance the read index if necessary.
         if ( currentMemLogReadIndex == currentMemLogWriteIndex )
         {
            currentMemLogReadIndex++;
            if ( currentMemLogReadIndex == MEMLOG_SIZE/2 )
            {
               currentMemLogReadIndex = 0;
            }
         }

         NU_Local_Control_Interrupts(savedInterruptState);

         //Standard operator 
         //(For Partition Analysis we have to consider that if we alloc size of 0 always as size of 1 then are partitions must be optimized for this)
         if (size == 0) size = 1;

         ((MemLogEntryNarrow_t*)memLog)[currentIndex].size = size;
         ((MemLogEntryNarrow_t*)memLog)[currentIndex].flags = 1;    //allocated

         //Standard operator
         void * ptr;
         ptr = malloc(size);

         ((MemLogEntryNarrow_t*)memLog)[currentIndex].addr = ptr;

         return ptr;
      }
      else
      {
         if (currentMemLogWriteIndex >= MEMLOG_SIZE/6 )
         {
            loggingEnabled = false;
            rd_write_text( "Allocation Logging is complete and DISABLED!\r\n\r\n");
         }
         // advance the read index if necessary.
         if ( currentMemLogReadIndex == currentMemLogWriteIndex )
         {
            currentMemLogReadIndex++;
            if ( currentMemLogReadIndex == MEMLOG_SIZE/6 )
            {
               currentMemLogReadIndex = 0;
            }
         }

         ((MemLogEntryWide_t*)memLog)[currentIndex].caller = (void *)(temp[0] - 4);
         ((MemLogEntryWide_t*)memLog)[currentIndex].prev_caller = (void *)*addr;
         NU_Local_Control_Interrupts(savedInterruptState);
         ((MemLogEntryWide_t*)memLog)[currentIndex].taskid = (void *)TCD_Current_Thread;
         ((MemLogEntryWide_t*)memLog)[currentIndex].size = size;
         ((MemLogEntryWide_t*)memLog)[currentIndex].flags = 1;    //allocated
         ((MemLogEntryWide_t*)memLog)[currentIndex].timestamp = *(volatile uint32_t *)0xfffbc410;   // for arm9

         //Standard operator
         if (size == 0) size = 1;

         void * ptr;
         ptr = malloc(size);

         ((MemLogEntryWide_t*)memLog)[currentIndex].addr = ptr;

         return ptr;
      }
   }
   else
   {
       //Standard operator
       if (size == 0) size = 1;

       void * ptr;
       ptr = malloc(size);

       return ptr;
   }
}
//#pragma CODE_SECTION ("section_ramset1_0")
void ::operator delete(void *ptr)
{
   uint32_t savedInterruptState;
   uint32_t currentIndex;

   asm(" STR R14, [R13, #0xC]");  //save stack address temp[0]
   asm(" STR R13, [R13, #0x10]");  //save pc return address temp[1]

   if ( loggingEnabled )
   {
      savedInterruptState = NU_Local_Control_Interrupts(NU_DISABLE_INTERRUPTS);

      // Note that this code is FRAGILE.  It peeks backwards on the stack to find the return
      // address of the caller.  The location of the return address on the stack can be easily changed
      // as a result of other changes in this function (i.e. adding local variables, etc).
      // The offsets may need to be adjusted if this function is touched.
      volatile unsigned int temp[2];

      unsigned int *addr = (unsigned int *)temp[0] - 1;
      unsigned int count = 1 + (0x20/4);   //current stack space ***

      //Scan for previous store
      while ((*addr & 0xFFFF0000) != 0xE92D0000)
      {
         if ((*addr & 0xFFFFF000) == 0xE24DD000)
         {
            //add offset in words
            count += ((*addr & 0xFFF) >> 2);
         }
         addr--;
      }

      count += MEM_bitLookupTable[*addr & 0xF];
      count += MEM_bitLookupTable[(*addr >>4) & 0xF];
      count += MEM_bitLookupTable[(*addr >> 8) & 0xF];
      count += MEM_bitLookupTable[(*addr >> 12) & 0xF];

      addr = (unsigned int *)temp[1] + count;
      // FRAGILE CODE ENDS HERE

      currentIndex = currentMemLogWriteIndex;
      currentMemLogWriteIndex++;

      if ( memLogNarrow )
      {
         if ( currentMemLogWriteIndex >= MEMLOG_SIZE/2 )
         {
            loggingEnabled = false;
            rd_write_text( "Allocation Logging is complete and DISABLED!\r\n\r\n");
         }
         // advance the read index if necessary.
         if ( currentMemLogReadIndex == currentMemLogWriteIndex )
         {
            currentMemLogReadIndex++;
            if ( currentMemLogReadIndex == MEMLOG_SIZE/2 )
            {
               currentMemLogReadIndex = 0;
            }
         }

         NU_Local_Control_Interrupts(savedInterruptState);

         // finish logging the fields.  these are thread safe so they dont need to be inside the protected section.
         ((MemLogEntryNarrow_t*)memLog)[currentIndex].addr = ptr;
         ((MemLogEntryNarrow_t*)memLog)[currentIndex].size = 0;
         ((MemLogEntryNarrow_t*)memLog)[currentIndex].flags = 2;    //unallocated
      }
      else
      {
         ((MemLogEntryWide_t*)memLog)[currentIndex].caller = (void *)(temp[0] - 4);
         ((MemLogEntryWide_t*)memLog)[currentIndex].prev_caller = (void *)*addr;

         if ( currentMemLogWriteIndex >= MEMLOG_SIZE/6 )
         {
            loggingEnabled = false;
            rd_write_text( "Allocation Logging is complete and DISABLED!\r\n\r\n");
         }
         // advance the read index if necessary.
         if ( currentMemLogReadIndex == currentMemLogWriteIndex )
         {
            currentMemLogReadIndex++;
            if ( currentMemLogReadIndex == MEMLOG_SIZE/6 )
            {
               currentMemLogReadIndex = 0;
            }
         }
         NU_Local_Control_Interrupts(savedInterruptState);

         // finish logging the fields.  these are thread safe so they dont need to be inside the protected section.
         ((MemLogEntryWide_t*)memLog)[currentIndex].addr = ptr;
         ((MemLogEntryWide_t*)memLog)[currentIndex].size = 0;
         ((MemLogEntryWide_t*)memLog)[currentIndex].flags = 2;    //unallocated
         ((MemLogEntryWide_t*)memLog)[currentIndex].taskid = (void *)TCD_Current_Thread;
         ((MemLogEntryWide_t*)memLog)[currentIndex].timestamp = *(volatile uint32_t *)0xfffbc410;   // for arm9
      }

      //Standard operator
      if (ptr != NULL) {
         free(ptr);
      }
   }
   else
   {
      //Standard operator
      if (ptr != NULL) {
        free(ptr);
      }
   }
}

如果你正在运行Linux，我建议尝试Valgrind http://www.valgrind.org/.