debug_new.cpp File Reference

Implementation of debug versions of new and delete to check leakage. More...

#include <new>
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "fast_mutex.h"
#include "static_assert.h"
#include "debug_new.h"

Include dependency graph for debug_new.cpp:


Classes

struct  new_ptr_list_t
 Structure to store the position information where new occurs. More...

Defines

#define _DEBUG_NEW_ALIGNMENT   16
 The alignment requirement of allocated memory blocks.
#define _DEBUG_NEW_CALLER_ADDRESS   __builtin_return_address(0)
 The expression to return the caller address.
#define _DEBUG_NEW_ERROR_ACTION   abort()
 The action to take when an error occurs.
#define _DEBUG_NEW_FILENAME_LEN   44
 The length of file name stored if greater than zero.
#define _DEBUG_NEW_PROGNAME   NULL
 The program (executable) name to be set at compile time.
#define _DEBUG_NEW_STD_OPER_NEW   1
 Macro to indicate whether the standard-conformant behaviour of operator new is wanted.
#define _DEBUG_NEW_TAILCHECK   0
 Macro to indicate whether a writing-past-end check will be performed.
#define _DEBUG_NEW_TAILCHECK_CHAR   0xCC
 Value of the padding bytes at the end of a memory block.
#define _DEBUG_NEW_USE_ADDR2LINE   1
 Whether to use addr2line to convert a caller address to file/line information.
#define _DEBUG_NEW_REDEFINE_NEW   0
 Macro to indicate whether redefinition of new is wanted.
#define align(s)   (((s) + _DEBUG_NEW_ALIGNMENT - 1) & ~(_DEBUG_NEW_ALIGNMENT - 1))
 Gets the aligned value of memory block size.

Functions

static bool print_position_from_addr (const void *addr)
 Tries printing the position information from an instruction address.
static void print_position (const void *ptr, int line)
 Prints the position information of a memory operation point.
static bool check_tail (new_ptr_list_t *ptr)
 Checks whether the padding bytes at the end of a memory block is tampered with.
static void * alloc_mem (size_t size, const char *file, int line, bool is_array)
 Allocates memory and initializes control data.
static void free_pointer (void *pointer, void *addr, bool is_array)
 Frees memory and adjusts pointers.
int check_leaks ()
 Checks for memory leaks.
int check_mem_corruption ()
 Checks for heap corruption.
void * operator new (size_t size, const char *file, int line)
void * operator new[] (size_t size, const char *file, int line)
void * operator new (size_t size) throw (std::bad_alloc)
void * operator new[] (size_t size) throw (std::bad_alloc)
void * operator new (size_t size, const std::nothrow_t &) throw ()
void * operator new[] (size_t size, const std::nothrow_t &) throw ()
void operator delete (void *pointer) throw ()
void operator delete[] (void *pointer) throw ()
void operator delete (void *pointer, const char *file, int line) throw ()
void operator delete[] (void *pointer, const char *file, int line) throw ()
void operator delete (void *pointer, const std::nothrow_t &) throw ()
void operator delete[] (void *pointer, const std::nothrow_t &) throw ()

Variables

const unsigned MAGIC = 0x4442474E
 Magic number for error detection.
const int ALIGNED_LIST_ITEM_SIZE = align(sizeof(new_ptr_list_t))
 The extra memory allocated by operator new.
static new_ptr_list_t new_ptr_list
 List of all new'd pointers.
static fast_mutex new_ptr_lock
 The mutex guard to protect simultaneous access to the pointer list.
static fast_mutex new_output_lock
 The mutex guard to protect simultaneous output to new_output_fp.
static size_t total_mem_alloc = 0
 Total memory allocated in bytes.
bool new_autocheck_flag = true
 Flag to control whether check_leaks will be automatically called on program exit.
bool new_verbose_flag = false
 Flag to control whether verbose messages are output.
FILE * new_output_fp = stderr
 Pointer to the output stream.
const char * new_progname = _DEBUG_NEW_PROGNAME
 Pointer to the program name.

Detailed Description

Implementation of debug versions of new and delete to check leakage.

Version:
4.12, 2007/12/31
Author:
Wu Yongwei

Define Documentation

#define _DEBUG_NEW_ALIGNMENT   16

The alignment requirement of allocated memory blocks.

It must be a power of two.

#define _DEBUG_NEW_CALLER_ADDRESS   __builtin_return_address(0)

The expression to return the caller address.

print_position will later on use this address to print the position information of memory operation points.

#define _DEBUG_NEW_ERROR_ACTION   abort()

The action to take when an error occurs.

The default behaviour is to call abort, unless _DEBUG_NEW_ERROR_CRASH is defined, in which case a segmentation fault will be triggered instead (which can be useful on platforms like Windows that do not generate a core dump when abort is called).

#define _DEBUG_NEW_FILENAME_LEN   44

The length of file name stored if greater than zero.

If it is zero, only a const char pointer will be stored. Currently the default behaviour is to copy the file name, because I found that the exit leakage check cannot access the address of the file name sometimes (in my case, a core dump will occur when trying to access the file name in a shared library after a SIGINT). The current default value makes the size of new_ptr_list_t 64 on 32-bit platforms.

#define _DEBUG_NEW_PROGNAME   NULL

The program (executable) name to be set at compile time.

It is better to assign the full program path to new_progname in main (at run time) than to use this (compile-time) macro, but this macro serves well as a quick hack. Note also that double quotation marks need to be used around the program name, i.e., one should specify a command-line option like -D_DEBUG_NEW_PROGNAME=\"a.out\" in bash, or -D_DEBUG_NEW_PROGNAME=\"a.exe\" in the Windows command prompt.

#define _DEBUG_NEW_REDEFINE_NEW   0

Macro to indicate whether redefinition of new is wanted.

Here it is defined to 0 to disable the redefinition of new.

#define _DEBUG_NEW_STD_OPER_NEW   1

Macro to indicate whether the standard-conformant behaviour of operator new is wanted.

It is on by default now, but the user may set it to 0 to revert to the old behaviour.

#define _DEBUG_NEW_TAILCHECK   0

Macro to indicate whether a writing-past-end check will be performed.

Define it to a positive integer as the number of padding bytes at the end of a memory block for checking.

#define _DEBUG_NEW_TAILCHECK_CHAR   0xCC

Value of the padding bytes at the end of a memory block.

#define _DEBUG_NEW_USE_ADDR2LINE   1

Whether to use addr2line to convert a caller address to file/line information.

Defining it to a non-zero value will enable the conversion (automatically done if GCC is detected). Defining it to zero will disable the conversion.

#define align (  )     (((s) + _DEBUG_NEW_ALIGNMENT - 1) & ~(_DEBUG_NEW_ALIGNMENT - 1))

Gets the aligned value of memory block size.


Function Documentation

static void* alloc_mem ( size_t  size,
const char *  file,
int  line,
bool  is_array 
) [static]

Allocates memory and initializes control data.

Parameters:
size size of the required memory block
file null-terminated string of the file name
line line number
is_array boolean value whether this is an array operation
Returns:
pointer to the user-requested memory area; NULL if memory allocation is not successful

int check_leaks (  ) 

Checks for memory leaks.

Returns:
zero if no leakage is found; the number of leaks otherwise

int check_mem_corruption (  ) 

Checks for heap corruption.

Returns:
zero if no problem is found; the number of found memory corruptions otherwise

static bool check_tail ( new_ptr_list_t ptr  )  [static]

Checks whether the padding bytes at the end of a memory block is tampered with.

Parameters:
ptr pointer to a new_ptr_list_t struct
Returns:
true if the padding bytes are untouched; false otherwise

static void free_pointer ( void *  pointer,
void *  addr,
bool  is_array 
) [static]

Frees memory and adjusts pointers.

Parameters:
pointer pointer to delete
addr pointer to the caller
is_array flag indicating whether it is invoked by a delete[] call

void operator delete ( void *  pointer,
const std::nothrow_t &   
) throw ()

void operator delete ( void *  pointer,
const char *  file,
int  line 
) throw ()

void operator delete ( void *  pointer  )  throw ()

void operator delete[] ( void *  pointer,
const std::nothrow_t &   
) throw ()

void operator delete[] ( void *  pointer,
const char *  file,
int  line 
) throw ()

void operator delete[] ( void *  pointer  )  throw ()

void* operator new ( size_t  size,
const std::nothrow_t &   
) throw ()

void* operator new ( size_t  size  )  throw (std::bad_alloc)

void* operator new ( size_t  size,
const char *  file,
int  line 
)

void* operator new[] ( size_t  size,
const std::nothrow_t &   
) throw ()

void* operator new[] ( size_t  size  )  throw (std::bad_alloc)

void* operator new[] ( size_t  size,
const char *  file,
int  line 
)

static void print_position ( const void *  ptr,
int  line 
) [static]

Prints the position information of a memory operation point.

When _DEBUG_NEW_USE_ADDR2LINE is defined to a non-zero value, this function will try to convert a given caller address to file/line information with addr2line.

Parameters:
ptr source file name if line is non-zero; caller address otherwise
line source line number if non-zero; indication that ptr is the caller address otherwise

static bool print_position_from_addr ( const void *  addr  )  [static]

Tries printing the position information from an instruction address.

This is the version that uses addr2line.

Parameters:
addr the instruction address to convert and print
Returns:
true if the address is converted successfully (and the result is printed); false if no useful information is got (and nothing is printed)


Variable Documentation

const int ALIGNED_LIST_ITEM_SIZE = align(sizeof(new_ptr_list_t))

The extra memory allocated by operator new.

const unsigned MAGIC = 0x4442474E

Magic number for error detection.

bool new_autocheck_flag = true

Flag to control whether check_leaks will be automatically called on program exit.

FILE* new_output_fp = stderr

Pointer to the output stream.

The default output is stderr, and one may change it to a user stream if needed (say, new_verbose_flag is true and there are a lot of (de)allocations).

fast_mutex new_output_lock [static]

The mutex guard to protect simultaneous output to new_output_fp.

const char* new_progname = _DEBUG_NEW_PROGNAME

Pointer to the program name.

Its initial value is the macro _DEBUG_NEW_PROGNAME. You should try to assign the program path to it early in your application. Assigning argv[0] to it in main is one way. If you use bash or ksh (or similar), the following statement is probably what you want: `new_progname = getenv("_");'.

new_ptr_list_t new_ptr_list [static]

Initial value:

 {
    &new_ptr_list,
    &new_ptr_list,
    0,
    {



        ""

    },
    0,
    0,
    MAGIC
}
List of all new'd pointers.

fast_mutex new_ptr_lock [static]

The mutex guard to protect simultaneous access to the pointer list.

bool new_verbose_flag = false

Flag to control whether verbose messages are output.

size_t total_mem_alloc = 0 [static]

Total memory allocated in bytes.


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