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#![allow(dead_code)] // Some functions for print debugging in here
use crate::backend::ir::*;
use crate::cruby::*;
use std::slice;
/// Trait for casting to [usize] that allows you to say `.as_usize()`.
/// Implementation conditional on the cast preserving the numeric value on
/// all inputs and being inexpensive.
///
/// [usize] is only guaranteed to be more than 16-bit wide, so we can't use
/// `.into()` to cast an `u32` or an `u64` to a `usize` even though in all
/// the platforms YJIT supports these two casts are pretty much no-ops.
/// We could say `as usize` or `.try_convert().unwrap()` everywhere
/// for those casts but they both have undesirable consequences if and when
/// we decide to support 32-bit platforms. Unfortunately we can't implement
/// [::core::convert::From] for [usize] since both the trait and the type are
/// external. Naming the method `into()` also runs into naming conflicts.
pub(crate) trait IntoUsize {
/// Convert to usize. Implementation conditional on width of [usize].
fn as_usize(self) -> usize;
}
#[cfg(target_pointer_width = "64")]
impl IntoUsize for u64 {
fn as_usize(self) -> usize {
self as usize
}
}
#[cfg(target_pointer_width = "64")]
impl IntoUsize for u32 {
fn as_usize(self) -> usize {
self as usize
}
}
impl IntoUsize for u16 {
/// Alias for `.into()`. For convenience so you could use the trait for
/// all unsgined types.
fn as_usize(self) -> usize {
self.into()
}
}
impl IntoUsize for u8 {
/// Alias for `.into()`. For convenience so you could use the trait for
/// all unsgined types.
fn as_usize(self) -> usize {
self.into()
}
}
/// Compute an offset in bytes of a given struct field
#[allow(unused)]
macro_rules! offset_of {
($struct_type:ty, $field_name:tt) => {{
// This is basically the exact example for
// "creating a pointer to uninitialized data" from `std::ptr::addr_of_mut`.
// We make a dummy local that hopefully is optimized away because we never
// read or write its contents. Doing this dance to avoid UB.
let mut instance = std::mem::MaybeUninit::<$struct_type>::uninit();
let base_ptr = instance.as_mut_ptr();
let field_ptr = unsafe { std::ptr::addr_of_mut!((*base_ptr).$field_name) };
(field_ptr as usize) - (base_ptr as usize)
}};
}
#[allow(unused)]
pub(crate) use offset_of;
// Convert a CRuby UTF-8-encoded RSTRING into a Rust string.
// This should work fine on ASCII strings and anything else
// that is considered legal UTF-8, including embedded nulls.
pub fn ruby_str_to_rust(v: VALUE) -> String {
let str_ptr = unsafe { rb_RSTRING_PTR(v) } as *mut u8;
let str_len: usize = unsafe { rb_RSTRING_LEN(v) }.try_into().unwrap();
let str_slice: &[u8] = unsafe { slice::from_raw_parts(str_ptr, str_len) };
match String::from_utf8(str_slice.to_vec()) {
Ok(utf8) => utf8,
Err(_) => String::new(),
}
}
// Location is the file defining the method, colon, method name.
// Filenames are sometimes internal strings supplied to eval,
// so be careful with them.
pub fn iseq_get_location(iseq: IseqPtr, pos: u16) -> String {
let iseq_label = unsafe { rb_iseq_label(iseq) };
let iseq_path = unsafe { rb_iseq_path(iseq) };
let iseq_lineno = unsafe { rb_iseq_line_no(iseq, pos as usize) };
let mut s = if iseq_label == Qnil {
"None".to_string()
} else {
ruby_str_to_rust(iseq_label)
};
s.push_str("@");
if iseq_path == Qnil {
s.push_str("None");
} else {
s.push_str(&ruby_str_to_rust(iseq_path));
}
s.push_str(":");
s.push_str(&iseq_lineno.to_string());
s
}
// TODO: we may want to move this function into yjit.c, maybe add a convenient Rust-side wrapper
/*
// For debugging. Print the bytecode for an iseq.
RBIMPL_ATTR_MAYBE_UNUSED()
static void
yjit_print_iseq(const rb_iseq_t *iseq)
{
char *ptr;
long len;
VALUE disassembly = rb_iseq_disasm(iseq);
RSTRING_GETMEM(disassembly, ptr, len);
fprintf(stderr, "%.*s\n", (int)len, ptr);
}
*/
#[cfg(target_arch = "aarch64")]
macro_rules! c_callable {
($(#[$outer:meta])*
fn $f:ident $args:tt $(-> $ret:ty)? $body:block) => {
$(#[$outer])*
extern "C" fn $f $args $(-> $ret)? $body
};
}
#[cfg(target_arch = "x86_64")]
macro_rules! c_callable {
($(#[$outer:meta])*
fn $f:ident $args:tt $(-> $ret:ty)? $body:block) => {
$(#[$outer])*
extern "sysv64" fn $f $args $(-> $ret)? $body
};
}
pub(crate) use c_callable;
pub fn print_int(asm: &mut Assembler, opnd: Opnd) {
c_callable!{
fn print_int_fn(val: i64) {
println!("{}", val);
}
}
asm.cpush_all();
let argument = match opnd {
Opnd::Mem(_) | Opnd::Reg(_) | Opnd::InsnOut { .. } => {
// Sign-extend the value if necessary
if opnd.rm_num_bits() < 64 {
asm.load_sext(opnd)
} else {
opnd
}
},
Opnd::Imm(_) | Opnd::UImm(_) => opnd,
_ => unreachable!(),
};
asm.ccall(print_int_fn as *const u8, vec![argument]);
asm.cpop_all();
}
/// Generate code to print a pointer
pub fn print_ptr(asm: &mut Assembler, opnd: Opnd) {
c_callable!{
fn print_ptr_fn(ptr: *const u8) {
println!("{:p}", ptr);
}
}
assert!(opnd.rm_num_bits() == 64);
asm.cpush_all();
asm.ccall(print_ptr_fn as *const u8, vec![opnd]);
asm.cpop_all();
}
/// Generate code to print a value
pub fn print_value(asm: &mut Assembler, opnd: Opnd) {
c_callable!{
fn print_value_fn(val: VALUE) {
unsafe { rb_obj_info_dump(val) }
}
}
assert!(matches!(opnd, Opnd::Value(_)));
asm.cpush_all();
asm.ccall(print_value_fn as *const u8, vec![opnd]);
asm.cpop_all();
}
/// Generate code to print constant string to stdout
pub fn print_str(asm: &mut Assembler, str: &str) {
c_callable!{
fn print_str_cfun(ptr: *const u8, num_bytes: usize) {
unsafe {
let slice = slice::from_raw_parts(ptr, num_bytes);
let str = std::str::from_utf8(slice).unwrap();
println!("{}", str);
}
}
}
asm.cpush_all();
let string_data = asm.new_label("string_data");
let after_string = asm.new_label("after_string");
asm.jmp(after_string);
asm.write_label(string_data);
asm.bake_string(str);
asm.write_label(after_string);
let opnd = asm.lea_label(string_data);
asm.ccall(print_str_cfun as *const u8, vec![opnd, Opnd::UImm(str.len() as u64)]);
asm.cpop_all();
}
#[cfg(test)]
mod tests {
use super::*;
use crate::asm::CodeBlock;
#[test]
fn min_max_preserved_after_cast_to_usize() {
use crate::utils::IntoUsize;
let min: usize = u64::MIN.as_usize();
assert_eq!(min, u64::MIN.try_into().unwrap());
let max: usize = u64::MAX.as_usize();
assert_eq!(max, u64::MAX.try_into().unwrap());
let min: usize = u32::MIN.as_usize();
assert_eq!(min, u32::MIN.try_into().unwrap());
let max: usize = u32::MAX.as_usize();
assert_eq!(max, u32::MAX.try_into().unwrap());
}
#[test]
fn test_offset_of() {
#[repr(C)]
struct Foo {
a: u8,
b: u64,
}
assert_eq!(0, offset_of!(Foo, a), "C99 6.7.2.1p13 says no padding at the front");
assert_eq!(8, offset_of!(Foo, b), "ABI dependent, but should hold");
}
#[test]
fn test_print_int() {
let mut asm = Assembler::new();
let mut cb = CodeBlock::new_dummy(1024);
print_int(&mut asm, Opnd::Imm(42));
asm.compile(&mut cb, None).unwrap();
}
#[test]
fn test_print_str() {
let mut asm = Assembler::new();
let mut cb = CodeBlock::new_dummy(1024);
print_str(&mut asm, "Hello, world!");
asm.compile(&mut cb, None).unwrap();
}
}
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