test.cpp

static void foo() asm("myfoo") __attribute__((section("mysect")));
static void foo() {}
static void bar() {}
const void* data[] = {
    (void*)&foo,
    (void*)&bar
};
struct Data {
        void* mine;
        unsigned int theirs;
};
#include <utility>
template <typename T>
static auto h(T& t)
{
        return &t;
}
struct S1 {
        void foo();
        [[gnu::section("mapping"), gnu::used]]
        static const inline Data dummy1 = {(void*)&S1::foo, 0x401000};
};

#define OW(address, method) \
        _Pragma("GCC diagnostic ignored \"-Wpmf-conversions\"") \
        [[gnu::section("mapping"), gnu::used]] \
        static const Data dummy21 = {(void*)&method, 0x ## address}
OW(401000, S1::foo);
void S1::foo()
{
}

test2.cpp

[[gnu::section("mydatarray")]]
int a1 = 1;

[[gnu::section("mydatarray")]]
int a2 = 2;

extern int __start_mydatarray;
extern int __stop_mydatarray;

#include <cstdio>
int main()
{
/*
    printf("%p, %p\n", &__start_mydatarray, &__stop_mydatarray);
    for (auto start = &__start_mydatarray, end = &__stop_mydatarray;
         start < end; ++start)
    {
        printf("%x\n", *start);
    }
*/
}