c++ - “Conditional jump or move depends on uninitialised value”，但是分配功能未在堆栈跟踪中列出。怎么样？

这是一些Valgrind日志的一部分:

== 1652 ==条件跳转或移动取决于未初始化的值
== 1652 == at 0x868DBFC:Dfm_db::io::Layer_cell_writer::end_cell()(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/Isrc/dfm_db_io_layer.C:224)
== 1652 ==通过0x862C9FD:Dfm_db::Hdb_layer_writer::end_cell()(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/../Isrc/dfm/dfm_db_io_layer.h:916)
== 1652 ==由0x861197F:Dfm_db::Hdb_writer::save_layer_geometries(Dfm_db::Hdb_layer_writer＆，Drc_Hierarchical_database＆，unsigned long，Drc_Hierarchical_geometry_type，bool，bool，bool，bool / layer / layer / type / ard_ard / dflv_produced() aoi-asserts-valg / dfm / Isrc / dfm_db_hdb_io.C:2362)
== 1652 ==通过0x8610755:Dfm_db::Hdb_writer::save_layer(Dfm_db::Database *，Drc_Hierarchical_database＆，unsigned long，unsigned long，Dfm_db::Geometry_types，char const *，Dfm_db::Run_info＆，const，＆Lafyer_db: char const *，bool，char const *，char const *，bool，Pdb_security *，bool，int，bool，bool，Dfm_db::must_be，Dfm_produced_layer_type)(/ home / lvardany / tmp_IWA / ic / lv / aoi-asserts- valg / dfm / Isrc / dfm_db_hdb_io.C:2102)
== 1652 ==通过0x8595B1E:Dfm_db::Database::save_layer(char const *，unsigned long，bool)(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/Isrc/dfm_database.C :2490)
== 1652 ==通过0x8594D39:Dfm_db::Database::save_layers(std::map，std::less，std::allocator>>>＆)(/ home / lvardany / tmp_IWA / ic / lv / aoi-asserts -valg / dfm / Isrc / dfm_database.C:2317)
== 1652 ==通过0x85937B8:Dfm_db::Database::save_revision(bool)(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/Isrc/dfm_database.C:2082)
== 1652 ==通过0x4C6AE76:Cockpit_cli::save_revision(Dfm_db::must_be)(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/Isrc/cockpit_db_rev_cli.C:520)
== 1652 ==通过0x4C15153:cockpit_save_revision(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/Isrc/cockpit_db_hier_rev_cmds.C:529)
== 1652 ==通过0xD8BAC67:TclEvalObjvInternal(在/amy/ic_wg_server/CACHED_WG_SERVER/ic/comp/exports.v0-0_6-19-2015_engr-aoi/mgc_home/pkgs/icv_lib.aoi/lib64/libcalibre_utils.so)
== 1652 ==通过0xD8E3255:TclExecuteByteCode(在/amy/ic_wg_server/CACHED_WG_SERVER/ic/comp/exports.v0-0_6_6-19-2015_engr-aoi/mgc_home/pkgs/icv_lib.aoi/lib64/libcalibre_utils.so)
== 1652 == by 0xD8E7280:TclCompEvalObj(在/amy/ic_wg_server/CACHED_WG_SERVER/ic/comp/exports.v0-0_6-19-2015_engr-aoi/mgc_home/pkgs/icv_lib.aoi/lib64/libcalibre_utils.so)
== 1652 ==未初始化的值是由堆栈分配创建的
== 1652 == at 0x859F6DC:Dfm_db::Database::get_pl_index_level()const(/home/lvardany/tmp_IWA/ic/lv/aoi-asserts-valg/dfm/Isrc/dfm_database.C:4325)

最后一行是 --track-orgins 选项的结果，该选项精确显示了在哪个函数中创建了未初始化的值。对我而言，此输出的唯一神奇之处在于，最后一个函数没有出现在调用堆栈中。还为 20 提供了 --num-callers 选项。

我的问题是最后一个函数怎么可能没有出现在调用堆栈中？

谢谢!

最佳答案

很容易。一个例子:

#include <functional>
#include <iostream>

std::function<void()> callback;

void foo()
{
   int x;
   callback = [&]() { if (x > 5) std::cout << "hi"; };
}

int main()
{
   foo();
   callback();
}

在这里，foo将不会出现在调用callback的调用堆栈中。

您的想法太线性了。