CODEWITHSUNDEEP
c++visual-studioassemblyx86
user997112
user997112

Reputation: 30605

Additional C++ bracket added in Visual Studio dissembly window?

I am looking at the Dissembly window in Visual Studio 2012 and I have the setting for interlacing C++ and generated ASM turned on. For this C++:

int main(){
    int h = my_func(6);
}

I get this ASM:

int main(){
 push        ebp  
 mov         ebp,esp  
 sub         esp,0CCh  
 push        ebx  
 push        esi  
 push        edi  
 lea         edi,[ebp-0CCh]  
 mov         ecx,33h  
 mov         eax,0CCCCCCCCh  
 rep stos    dword ptr es:[edi]  
    int h = my_func(4);
 push        4  
 call        my_func (0121159h)  
 add         esp,4  
 mov         dword ptr [h],eax  
}
 xor         eax,eax  
 pop         edi  
 pop         esi  
 pop         ebx  
 add         esp,0CCh  
 cmp         ebp,esp  
}                                         //What is this bracket??????
 call        __RTC_CheckEsp (01212E9h)  
 mov         esp,ebp  
 pop         ebp  
 ret

What is the odd bracket towards the end of the ASM? It doesn't have a corresponding bracket?

Upvotes: 0

Views: 81

Answers (1)

Ben Voigt
Ben Voigt

Reputation: 283614

If you turn on the setting to include source line numbers in the interleaved listing, I think you'll see that both braces are the same, the end of the main function.

It's completely normal for one line of C++ code to generate more than one instruction, and it's not unusual for those instructions to appear in multiple non-consecutive blocks. (In fact, when optimization is enabled, multiple blocks is the rule rather than the exception.)

This mixed listing contains the true machine code the compiler generated, expressed as assembly to make it easier to read. The C++ snippets are annotations telling you why the compiler generated each bit of assembly. The C++ snippets cannot be recombined into a complete C++ program.

Upvotes: 3

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