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--gnu_instrument, --no_gnu_instrument

This option inserts GCC-style instrumentation calls for profiling entry and exit to functions.


After function entry and before function exit, the following profiling functions are called with the address of the current function and its call site:

void __cyg_profile_func_enter(void *current_func, void *callsite);
void __cyg_profile_func_exit(void *current_func, void *callsite);


You must provide definitions of __cyg_profile_func_enter() and __cyg_profile_func_exit().

It is necessary to explicitly mark __cyg_profile_func_enter() and __cyg_profile_func_exit() with __attribute__((no_instrument_function)).