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#ifdef _REENTRANT
#include <stdatomic.h>
extern void __wasi_init_tp(void);
#endif
#include <wasi/api.h>
extern void __wasm_call_ctors(void);
extern int __main_void(void);
extern void __wasm_call_dtors(void);
__attribute__((export_name("_start")))
void _start(void) {
// Commands should only be called once per instance. This simple check
// ensures that the `_start` function isn't started more than once.
//
// We use `volatile` here to prevent the store to `started` from being
// sunk past any subsequent code, and to prevent any compiler from
// optimizing based on the knowledge that `_start` is the program
// entrypoint.
#ifdef _REENTRANT
static volatile _Atomic int started = 0;
int expected = 0;
if (!atomic_compare_exchange_strong(&started, &expected, 1)) {
__builtin_trap();
}
#else
static volatile int started = 0;
if (started != 0) {
__builtin_trap();
}
started = 1;
#endif
#ifdef _REENTRANT
__wasi_init_tp();
#endif
// The linker synthesizes this to call constructors.
__wasm_call_ctors();
// Call `__main_void` which will either be the application's zero-argument
// `__main_void` function or a libc routine which obtains the command-line
// arguments and calls `__main_argv_argc`.
int r = __main_void();
// Call atexit functions, destructors, stdio cleanup, etc.
__wasm_call_dtors();
// If main exited successfully, just return, otherwise call
// `__wasi_proc_exit`.
if (r != 0) {
__wasi_proc_exit(r);
}
}
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