I found that when I compile my C / C ++ programs with VS2010 (I did not check other compilers) in debug mode, when I look at disassembly, all function calls, be it library functions, my own functions, function class- members etc. all have a two-stage call. The actual function call is converted to an instruction call
at address A. When I go to address A, I see that this is some sort of a large list of instructions jmp
, each of which has a different function. A (small) part may look like this:
fooFunc:
08CB1776 jmp fooFunc (8D11F60h)
barFunc:
08CB177B jmp barFunc (8D25240h)
std::allocator<unsigned int>::max_size:
08CB1780 jmp std::allocator<unsigned int>::max_size (8CE3D00h)
std::_Copy_backward_opt<int *,int *>:
08CB1785 jmp std::_Copy_backward_opt<int *,int *> (8D325D0h)
std::_Checked_base<int *>:
08CB178A jmp std::_Checked_base<int *> (8D32360h)
@ILT+1950(_foobarFunc):
08CB17A3 jmp foobarFunc (8F31450h)
@ILT+1955(_anotherFunc):
08CB17A8 jmp anotherFunc (8E4BD20h)
std::vector<unsigned short,std::allocator<unsigned short> >::capacity:
08CB17B2 jmp std::vector<unsigned short,std::allocator<unsigned short> >::capacity (8D8AAF0h)
yetAnother:
08CB17B7 jmp yetAnother (8D18630h)
@ILT+1975(_f):
08CB17BC jmp f (8E4FC50h)
std::_Debug_range<char *>:
08CB17C6 jmp std::_Debug_range<char *> (8D32480h)
std::_Vector_const_iterator<MyClass *,std::allocator<MyClass *> >::operator+=:
08CB17CB jmp std::_Vector_const_iterator<MyClass *,std::allocator<MyClass *> >::operator+= (8D64C80h)
These instructions jmp
, in turn, go to the actual function bodies. This only happens when compiling in debug mode. In Release functions, calls are compiled into direct calls to the function body.
?