beginnings of zig ir parser

test/stage2/ir.zig

@@ -0,0 +1,37 @@
+test "hello world IR" {
+    exeCmp(
+        \\@0 = "Hello, world!\n"
+        \\
+        \\@1 = fn({
+        \\  %0 : usize = 1 ;SYS_write
+        \\  %1 : usize = 1 ;STDOUT_FILENO
+        \\  %2 = ptrtoint(@0) ; msg ptr
+        \\  %3 = fieldptr(@0, "len") ; msg len ptr
+        \\  %4 = deref(%3) ; msg len
+        \\  %5 = asm("syscall",
+        \\    volatile=1,
+        \\    output="={rax}",
+        \\    inputs=["{rax}", "{rdi}", "{rsi}", "{rdx}"],
+        \\    clobbers=["rcx", "r11", "memory"],
+        \\    args=[%0, %1, %2, %4])
+        \\
+        \\  %6 : usize = 231 ;SYS_exit_group
+        \\  %7 : usize = 0   ;exit code
+        \\  %8 = asm("syscall",
+        \\    volatile=1,
+        \\    output="={rax}",
+        \\    inputs=["{rax}", "{rdi}"],
+        \\    clobbers=["rcx", "r11", "memory"],
+        \\    args=[%6, %7])
+        \\
+        \\  %9 = unreachable()
+        \\}, cc=naked);
+        \\
+        \\@2 = export("_start", @1)
+    ,
+        \\Hello, world!
+        \\
+    );
+}
+
+fn exeCmp(src: []const u8, expected_stdout: []const u8) void {}