memfd_secret-shim/src/ifunc.h

#ifndef _IT_IFUNC_H
#define _IT_IFUNC_H
//! ifunc helpers

#if !IFUNC_PREFIX
#define IFUNC_PREFIX _ifun__
#endif

#define _IFUNC_STR_(X) #X
#define _IFUNC_STR(X) _IFUNC_STR_(X)

#define _IFUNC_PREFIX_S _IFUNC_STR(IFUNC_PREFIX)

#define _IFUNC_PASTE_(X,Y) X##Y
#define _IFUNC_PASTE(X,Y) _IFUNC_PASTE_(X,Y)

#define _IFUNC_PREFIX(X) _IFUNC_PASTE(IFUNC_PREFIX, X)

#define IFUNC_NAME(name, ver) _impl__ ## name ## __ ## ver 
#define IFUNC_IMPL(name, ver) __attribute__((copy(name))) IFUNC_NAME(name, ver)
#define IFUNC_RESOLVER_A(attr, name)  __attribute__((returns_nonnull)) (* __attribute__(attr) _IFUNC_PREFIX(name) /*_ifun__ ## name*/ (void)) // When the ifunc resolver wants to return a function pointer that has attributes on it, the attribute inner list (e.g. `(returns_nonnull, const, nonnull)') can be provided as the first argument
#define IFUNC_RESOLVER(name)  IFUNC_RESOLVER_A((copy(name)), name)
#define IFUNC_DEF(name, params) name params __attribute__((__ifunc__(_IFUNC_PREFIX_S #name)))

#endif /* _IT_IFUNC_H */