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YJIT: Remove CString allocation when using src_loc!()

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Since we often take the VM lock as the first thing we do when entering
YJIT, and that needs a `src_loc!()`, this removes a allocation from
that. The main trick here is `concat!(file!(), '\0')` to get a C string
statically baked into the binary.
This commit is contained in:
Alan Wu 2024-04-29 15:55:10 -04:00
parent de0ad3be8e
commit 470eceff8f
1 changed files with 11 additions and 12 deletions
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23
yjit/src/cruby.rs
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@ -83,7 +83,7 @@
#![allow(non_upper_case_globals)] #![allow(non_upper_case_globals)]
use std::convert::From; use std::convert::From;
use std::ffi::CString; use std::ffi::{CString, CStr};
use std::os::raw::{c_char, c_int, c_uint}; use std::os::raw::{c_char, c_int, c_uint};
use std::panic::{catch_unwind, UnwindSafe}; use std::panic::{catch_unwind, UnwindSafe};
@ -208,8 +208,6 @@ pub use rb_RCLASS_ORIGIN as RCLASS_ORIGIN;
/// Helper so we can get a Rust string for insn_name() /// Helper so we can get a Rust string for insn_name()
pub fn insn_name(opcode: usize) -> String { pub fn insn_name(opcode: usize) -> String {
use std::ffi::CStr;
unsafe { unsafe {
// Look up Ruby's NULL-terminated insn name string // Look up Ruby's NULL-terminated insn name string
let op_name = raw_insn_name(VALUE(opcode)); let op_name = raw_insn_name(VALUE(opcode));
@ -608,7 +606,6 @@ pub fn rust_str_to_sym(str: &str) -> VALUE {
pub fn cstr_to_rust_string(c_char_ptr: *const c_char) -> Option<String> { pub fn cstr_to_rust_string(c_char_ptr: *const c_char) -> Option<String> {
assert!(c_char_ptr != std::ptr::null()); assert!(c_char_ptr != std::ptr::null());
use std::ffi::CStr;
let c_str: &CStr = unsafe { CStr::from_ptr(c_char_ptr) }; let c_str: &CStr = unsafe { CStr::from_ptr(c_char_ptr) };
match c_str.to_str() { match c_str.to_str() {
@ -620,17 +617,20 @@ pub fn cstr_to_rust_string(c_char_ptr: *const c_char) -> Option<String> {
/// A location in Rust code for integrating with debugging facilities defined in C. /// A location in Rust code for integrating with debugging facilities defined in C.
/// Use the [src_loc!] macro to crate an instance. /// Use the [src_loc!] macro to crate an instance.
pub struct SourceLocation { pub struct SourceLocation {
pub file: CString, pub file: &'static CStr,
pub line: c_int, pub line: c_int,
} }
/// Make a [SourceLocation] at the current spot. /// Make a [SourceLocation] at the current spot.
macro_rules! src_loc { macro_rules! src_loc {
() => { () => {
// NOTE(alan): `CString::new` allocates so we might want to limit this to debug builds. {
$crate::cruby::SourceLocation { // Nul-terminated string with static lifetime, make a CStr out of it safely.
file: std::ffi::CString::new(file!()).unwrap(), // ASCII source file paths let file: &'static str = concat!(file!(), '\0');
line: line!().try_into().unwrap(), // not that many lines $crate::cruby::SourceLocation {
file: unsafe { std::ffi::CStr::from_ptr(file.as_ptr().cast()) },
line: line!().try_into().unwrap(),
}
} }
}; };
} }
@ -668,17 +668,16 @@ where
Err(_) => { Err(_) => {
// Theoretically we can recover from some of these panics, // Theoretically we can recover from some of these panics,
// but it's too late if the unwind reaches here. // but it's too late if the unwind reaches here.
use std::{process, str};
let _ = catch_unwind(|| { let _ = catch_unwind(|| {
// IO functions can panic too. // IO functions can panic too.
eprintln!( eprintln!(
"YJIT panicked while holding VM lock acquired at {}:{}. Aborting...", "YJIT panicked while holding VM lock acquired at {}:{}. Aborting...",
str::from_utf8(loc.file.as_bytes()).unwrap_or("<not utf8>"), loc.file.to_string_lossy(),
line, line,
); );
}); });
process::abort(); std::process::abort();
} }
}; };