有选择地忽略MSVC中的帧指针

Question

In GCC i can selectively set optimization flags for specific function, so this:

void func() {}

generates:

func():
    push    rbp
    mov     rbp, rsp
    nop
    pop     rbp
    ret

And this:

__attribute__((optimize("-fomit-frame-pointer")))
void func() {}

generates:

func():
        nop
        ret

How can i do the same in visual studio?

Answer 1

There's a command line parameter to the compiler, /Oy , this makes the compiler to omit frame pointers. You can achieve the same with #pragma :

#pragma optimize("y", on)

int foo(int a) { // foo will be compiled with omitted frame pointers
    return a;
}

#pragma optimize("y", off)

Here, foo() will be compiled with omitted frame pointers.

Note: As I see, you have to build an optimized build to make this option have an effect. So, either supply some optimization flag to the compiler (like "/Og"), or include "g" into the pragma: #pragma optimize("gy", ...)

(I've checked this with Visual Studio 2015)