I was just investigating the trampoline implementation.I have defined
following macros in machine.h file.
#define TRAMPOLINE_SIZE (32 + GET_MODE_SIZE (ptr_mode) * 2)
#define TRAMPOLINE_ALIGNMENT GET_MODE_BITSIZE (ptr_mode)
#define INITIALIZE_TRAMPOLINE(ADDR, FUNC, CHAIN) \
{ \
rtx func_addr, chain_addr; \
\
func_addr = plus_constant (ADDR, 32); \
chain_addr = plus_constant (func_addr, GET_MODE_SIZE (ptr_mode)); \
emit_move_insn (gen_rtx_MEM (ptr_mode, func_addr), FUNC); \
emit_move_insn (gen_rtx_MEM (ptr_mode, chain_addr), CHAIN); \
\
}
The c code for which i'm observing the effect is as follows.
int foo(int (*f)()){
(*f)();
}
main(){
int g(){printf("hello");}
foo(g);
}
But if i comment out the body of macro INITIALIZE_TRAMPOLINE .Nothing
gets changed in the generated assembly file.
According to gcc internals INITIALIZE_TRAMPOLINE is responsible for
initialising the variable parts of a trampoline.
Would you please tell me when does the macros INITIALIZE_TRAMPOLINE
and TRAMPOLINE_TEMPLATE come in effect.Any practical expample will be
helpful.
