x86_64 compiler + elf output (can compile code that returns exit code)

src/backend/test.rs

@@ -0,0 +1,31 @@
+use crate::backend::{
+    Addr, elf,
+    x86_64::{Asm, Instr, mov, reg::*},
+};
+use std::{fs::OpenOptions, io::Write, os::unix::fs::OpenOptionsExt, process::Command};
+
+pub fn test_x86_64() {
+    let asm = Asm {
+        instrs: vec![mov(eax, 1), mov(ebx, 39), Instr::Int { code: 0x80 }],
+    };
+    let mut out = Vec::new();
+    asm.compile(&mut out).expect("failed to compile");
+    let binary = elf::create(&out, Addr(0));
+    let path = "./x86_64_test";
+    let mut file = OpenOptions::new()
+        .create(true)
+        .write(true)
+        .truncate(true)
+        .mode(0o750)
+        .open(path)
+        .expect("Failed to create file");
+    file.write_all(&binary).expect("Failed to write to file");
+    file.sync_all().expect("Failed to sync file");
+    drop(file);
+    println!("running...");
+    let mut proc = Command::new(path).spawn().expect("failed to run");
+    let status = proc.wait().expect("failed to wait");
+    if let Some(code) = status.code() {
+        std::process::exit(code);
+    }
+}