Function without prologue and epilogue


How to define a function without a prologue and epilogue so that only the body code is generated?

For example, so that the function

void func() {
    __asm__ volatile__ ("nop");

compiled to code

0:  90                      nop

instead of code

0:  55                      push   %ebp
1:  89 e5                   mov    %esp,%ebp
3:  90                      nop
4:  5d                      pop    %ebp
5:  c3                      ret    

Are there standard C (visual c, gcc) facilities?


There is no such possibility in the C standard. It can be provided by specific compilers. For example, for Visual C ++ on x86 platform it will look like this:

__declspec( naked ) void func( void ) { __asm { nop } }

For ARM gcc:

void func() __attribute__ ((naked));

void func(void) {
    __asm__ __volatile__("nop");
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