zig/std/special/bootstrap.zig

61 lines
1.6 KiB
Zig

// This file is in a package which has the root source file exposed as "@root".
// It is included in the compilation unit when exporting an executable.
const root = @import("@root");
const std = @import("std");
const want_main_symbol = std.target.linking_libc;
const want_start_symbol = !want_main_symbol;
const exit = std.os.posix.exit;
var argc_ptr: &usize = undefined;
export nakedcc fn _start() -> noreturn {
if (!want_start_symbol) {
@setGlobalLinkage(_start, GlobalLinkage.Internal);
unreachable;
}
switch (@compileVar("arch")) {
Arch.x86_64 => {
argc_ptr = asm("lea %[argc], [rsp]": [argc] "=r" (-> &usize));
},
Arch.i386 => {
argc_ptr = asm("lea %[argc], [esp]": [argc] "=r" (-> &usize));
},
else => @compileError("unsupported arch"),
}
callMainAndExit()
}
fn callMainAndExit() -> noreturn {
const argc = *argc_ptr;
const argv = @ptrCast(&&u8, &argc_ptr[1]);
const envp = @ptrCast(&?&u8, &argv[argc + 1]);
callMain(argc, argv, envp) %% exit(1);
exit(0);
}
fn callMain(argc: usize, argv: &&u8, envp: &?&u8) -> %void {
std.os.args.raw = argv[0...argc];
var env_count: usize = 0;
while (envp[env_count] != null; env_count += 1) {}
std.os.environ_raw = @ptrCast(&&u8, envp)[0...env_count];
std.debug.user_main_fn = root.main;
return root.main();
}
export fn main(c_argc: i32, c_argv: &&u8, c_envp: &?&u8) -> i32 {
if (!want_main_symbol) {
@setGlobalLinkage(main, GlobalLinkage.Internal);
unreachable;
}
callMain(usize(c_argc), c_argv, c_envp) %% return 1;
return 0;
}