Question

我按照here

所述，使用DEBUG_LEAKING_SCALARS编译perl

案例1
我按照DOC来测试内存泄漏报告：

env PERL_DESTRUCT_LEVEL=2 valgrind perl -e '@x; $x[0]=\@x'
==7216== Memcheck, a memory error detector
==7216== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==7216== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==7216== Command: perl -e @x;\ $x[0]=\\@x
==7216== 
==7216== 
==7216== HEAP SUMMARY:
==7216==     in use at exit: 0 bytes in 0 blocks
==7216==   total heap usage: 1,310 allocs, 1,310 frees, 171,397 bytes allocated
==7216== 
==7216== All heap blocks were freed -- no leaks are possible
==7216== 
==7216== For counts of detected and suppressed errors, rerun with: -v
==7216== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

没有任何报道。

案例2
我甚至在我的XS sub中做this thing。恰好：

#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include "XSUtils.h"
#include "ppport.h"

void
call_perl() {
    SV *sv;
    sv =  sv_2mortal( newSVpv( "XS::Utils::hello", 0 ) );

    newSViv( 323 );     //<<<< SHOULD LEAK
    printf( "Hi 3\n" );

    ENTERSCOPE;
    CALLPERL( sv , G_DISCARD|G_NOARGS );
    LEAVESCOPE;
}

MODULE = XS::Utils                    PACKAGE = XS::Utils

void
test()
    CODE:
        call_perl();

Link to the REPO

$ env PERL_DESTRUCT_LEVEL=2 valgrind perl -Iblib/arch/ -Iblib/lib -MXS::Utils -e 'XS::Utils::test()' 
==7308== Memcheck, a memory error detector
==7308== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==7308== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==7308== Command: perl -Iblib/arch/ -Iblib/lib -MXS::Utils -e XS::Utils::test()
==7308== 
Hi 3
Hello
==7308== 
==7308== HEAP SUMMARY:
==7308==     in use at exit: 1,502 bytes in 5 blocks
==7308==   total heap usage: 12,876 allocs, 12,871 frees, 1,945,298 bytes allocated
==7308== 
==7308== LEAK SUMMARY:
==7308==    definitely lost: 0 bytes in 0 blocks
==7308==    indirectly lost: 0 bytes in 0 blocks
==7308==      possibly lost: 0 bytes in 0 blocks
==7308==    still reachable: 1,502 bytes in 5 blocks
==7308==         suppressed: 0 bytes in 0 blocks
==7308== Rerun with --leak-check=full to see details of leaked memory
==7308== 
==7308== For counts of detected and suppressed errors, rerun with: -v
==7308== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

没有任何报道

案例3
我修复了模块Devel::LeakTrace（FIX）：

$ perl -MDevel::LeakTrace -Iblib/arch/ -Iblib/lib -MXS::Utils -e 'XS::Utils::test()' 
Hi 3
Hello

没有任何报道

案例4
我只发现Test::LeakTrace完成了它的工作：

$ perl -MTest::LeakTrace::Script=-verbose -Iblib/arch/ -Iblib/lib -MXS::Utils -e 'XS::Utils::test()' 
Hi 3
Hello
leaked SCALAR(0x208e1c0) from -e line 1.
ALLOCATED at -e:1 by entersub (parent 0x0); serial 9642
SV = IV(0x208e1b0) at 0x208e1c0
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 323

为什么在perl中内置工具报告没有泄漏？
我错了什么？如何使用DEBUG_LEAKING_SCALARS工具调试泄漏的内存？

Answer 1

实际上不是答案，而是来自 Dave Mitchell ：

DEBUG_LEAKING_SCALARS的主要目的不是列出泄漏的标量   （!!）
  这有助于追踪通常与泄露的标量有关的事情   和引用问题。它的两个主要特征是它变成了SV   从宏分配到功能，这样你就可以轻松了   附上一个断点;并且它为每个SV显示添加了仪器   它被分配的地方（由Devel :: Peek显示）。

但我不知道要调试什么，因为我不知道有什么东西在泄漏。像上面描述的 CASE 1到3 。我确信：

newSViv( 323 );

没有泄漏。

因此DEBUG_LEAKING_SCALARS 应列出泄露的标量

此外，我在perl提交历史记录中找到了此评论：

- [24088]作者：davem on 2005/03/28 21:38:44
- 日志：展开-DDEBUG_LEAKING_SCALARS以检测每个SV的创建

这对我的this任务非常有用。

使用`DEBUG_LEAKING_SCALARS`编译perl时，为什么不报告内存泄漏？

1 个答案: