可以将此文件 https://github.com/dataroaring/tools/blob/main/gdb/dbinit_stl_views-1.03.txt 放置到~/.gdbinit中使用 STL-View。STL-View 输出非常友好，支持 pvector，plist，plist_member，pmap，pmap_member，pset，pdequeue，pstack，pqueue，ppqueue，pbitset，pstring，pwstring。以 Apache Doris 中使用 pvector 为例，它能够输出 vector 中的所有元素。
(gdb) pvector block.data
elem[0]: $5 = {
column = {
<COW<doris::vectorized::IColumn>::intrusive_ptr<doris::vectorized::IColumn const>> = {
t = 0x606000fdc820
}, <No data fields>},type = {
<std::__shared_ptr<doris::vectorized::IDataType const, (__gnu_cxx::_Lock_policy)2>> = {
<std::__shared_ptr_access<doris::vectorized::IDataType const, (__gnu_cxx::_Lock_policy)2, false, false>> = {<No data fields>},
members of std::__shared_ptr<doris::vectorized::IDataType const, (__gnu_cxx::_Lock_policy)2>:
_M_ptr = 0x6030069e9780,
_M_refcount = {
_M_pi = 0x6030069e9770
}
}, <No data fields>},name = {
static npos = 18446744073709551615,
_M_dataplus = {
<std::allocator<char>> = {
<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>},
members of std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider:
_M_p = 0x61400006e068 "n_nationkey"
},
_M_string_length = 11,
{
_M_local_buf = "n_nationkey\000\276\276\276\276",
_M_allocated_capacity = 7957695015158701934
}}
}
elem[1]: $6 = {
column = {
<COW<doris::vectorized::IColumn>::intrusive_ptr<doris::vectorized::IColumn const>> = {
t = 0x6080001ec220
}, <No data fields>},type = {
...
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Pretty-Printer
GCC 7.0 开始支持了 Pretty-Printer 打印 STL 容器，可以将以下代码放置到~/.gdbinit中使 Pretty-Printer 生效。
注意：/usr/share/gcc/python需要更换为本机对应的地址。
python
import sys
sys.path.insert(0, '/usr/share/gcc/python')
from libstdcxx.v6.printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end
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以 vector 为例， Pretty-Printer 能够打印出详细内容。
(gdb) p block.data
$1 = std::vector of length 7, capacity 8 = {{
column = {
<COW<doris::vectorized::IColumn>::intrusive_ptr<doris::vectorized::IColumn const>> = {
t = 0x606000fdc820
}, <No data fields>},
type = std::shared_ptr<const doris::vectorized::IDataType> (use count 1, weak count 0) = {
get() = 0x6030069e9780
},
name = "n_nationkey"}, {
column = {
<COW<doris::vectorized::IColumn>::intrusive_ptr<doris::vectorized::IColumn const>> = {
t = 0x6080001ec220
}, <No data fields>},
type = std::shared_ptr<const doris::vectorized::IDataType> (use count 1, weak count 0) = {
get() = 0x6030069e9750
},
name = "n_name"}, {
column = {
<COW<doris::vectorized::IColumn>::intrusive_ptr<doris::vectorized::IColumn const>> = {
t = 0x606000fd52c0
}, <No data fields>},
type = std::shared_ptr<const doris::vectorized::IDataType> (use count 1, weak count 0) = {
get() = 0x6030069e9720
},
name = "n_regionkey"}, {
column = {
<COW<doris::vectorized::IColumn>::intrusive_ptr<doris::vectorized::IColumn const>> = {
t = 0x6030069e96b0
}, <No data fields>},
type = std::shared_ptr<const doris::vectorized::IDataType> (use count 1, weak count 0) = {
get() = 0x604000a66160
},
name = "n_comment"
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Boost Pretty Printer
因为 Apache Doris 使用 Boost 不多，因此不再举例。
可以参考：https://github.com/ruediger/Boost-Pretty-Printer
总结
有了 Sanitizer 能够在单测、功能、集成、压力测试环境及时发现问题，最重要的是大多数时候都可以给出程序出问题的关联现场，比如内存分配的调用栈，释放内存的调用栈，非法访问内存的调用栈，配合 Core Dump 可以查看现场状态，解决 C++ 内存问题从猜测变成了有证据的现场分析。
作者介绍：杨勇强，SelectDB 联合创始人兼产品VP，同时也是Apache Doris Committer。曾担任百度智能云存储部总架构师，主导构建了云存储技术产品体系，是Linux内核社区贡献者。
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