如何在gdb的所有构造函数中为C++对象同时设置断点？

Question

我有一个C++对象，它有20个构造函数，我想知道哪个特定的构造函数被调用。

Answer 1

您可以使用rbreak。见documentation：

rbreak regex

Set breakpoints on all functions matching the regular expression regex. This command sets an unconditional breakpoint on all matches, printing a list of all breakpoints it set. Once these breakpoints are set, they are treated just like the breakpoints set with the break command. You can delete them, disable them, or make them conditional the same way as any other breakpoint.

例子：

class Foo { 
public: 
    Foo() {} 
    Foo(int) {} 
}; 

int main() { 
    Foo f1; 
    Foo f2(1); 
    return 0; 
} 

GDB会话：

[ ~]$ gdb -q a.out 
Reading symbols from a.out...done. 
(gdb) rbreak Foo::Foo 
Breakpoint 1 at 0x4004dc: file so-rbr.cpp, line 3. 
void Foo::Foo(); 
Breakpoint 2 at 0x4004eb: file so-rbr.cpp, line 4. 
void Foo::Foo(int); 
(gdb) i b 
Num  Type   Disp Enb Address   What 
1  breakpoint  keep y 0x00000000004004dc in Foo::Foo() at so-rbr.cpp:3 
2  breakpoint  keep y 0x00000000004004eb in Foo::Foo(int) at so-rbr.cpp:4 
(gdb) 

Answer 2

只要运行break myNamespace::myClass::myClass，gdb就会在每个构造函数中断开。

例如，如果您想要创建任何具有至少2个构造函数的runtime_error，您可以运行break std::runtime_error::runtime_error。 gdb输出将如下所示：

Breakpoint 4 at 0xaf20 (4 locations) 

这表明断点设置为多个构造函数。要检查运行info breakpoints将提供输出这样的断点的位置：

Num  Type   Disp Enb Address   What 
1  breakpoint  keep y <MULTIPLE>   
1.1       y  0x000000000000af20 <std::runtime_error::runtime_error(char const*)@plt> 
1.2       y  0x000000000000b300 <std::runtime_error::runtime_error(std::runtime_error const&)@plt> 
1.3       y  0x000000000000b460 <std::runtime_error::runtime_error(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)@plt> 
1.4       y  0x000000000000b5e0 <std::runtime_error::runtime_error(char const*)@plt>