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avoid allocation in read_os_string_from_c_string

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This commit is contained in:
Ralf Jung 2019-12-04 10:16:08 +01:00
parent 808ac8f4b9
commit 01f060b6da
2 changed files with 10 additions and 7 deletions
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13
src/helpers.rs
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@ -1,5 +1,5 @@
use std::{mem, iter};
use std::ffi::{OsStr, OsString};
use std::ffi::OsStr;
use syntax::source_map::DUMMY_SP;
use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX};
@ -453,9 +453,12 @@ fn try_unwrap_io_result<T: From<i32>>(
/// Helper function to read an OsString from a null-terminated sequence of bytes, which is what
/// the Unix APIs usually handle.
fn read_os_string_from_c_string(&mut self, scalar: Scalar<Tag>) -> InterpResult<'tcx, OsString> {
let bytes = self.eval_context_mut().memory.read_c_str(scalar)?;
Ok(bytes_to_os_str(bytes)?.into())
fn read_os_string_from_c_string<'a>(&'a self, scalar: Scalar<Tag>) -> InterpResult<'tcx, &'a OsStr>
where 'tcx: 'a, 'mir: 'a
{
let this = self.eval_context_ref();
let bytes = this.memory.read_c_str(scalar)?;
bytes_to_os_str(bytes)
}
/// Helper function to write an OsStr as a null-terminated sequence of bytes, which is what
@ -501,7 +504,7 @@ fn os_str_to_bytes<'tcx, 'a>(os_str: &'a OsStr) -> InterpResult<'tcx, &'a [u8]>
}
#[cfg(not(target_os = "unix"))]
fn bytes_to_os_str<'tcx, 'a>(bytes: &'a[u8]) -> InterpResult<'tcx, &'a OsStr> {
fn bytes_to_os_str<'tcx, 'a>(bytes: &'a [u8]) -> InterpResult<'tcx, &'a OsStr> {
let s = std::str::from_utf8(bytes)
.map_err(|_| err_unsup_format!("{:?} is not a valid utf-8 string", bytes))?;
Ok(&OsStr::new(s))

4
src/machine.rs
View File

@ -140,8 +140,8 @@ pub(crate) fn new(communicate: bool) -> Self {
/// A little trait that's useful to be inherited by extension traits.
pub trait MiriEvalContextExt<'mir, 'tcx> {
fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx>;
fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx>;
fn eval_context_ref<'a>(&'a self) -> &'a MiriEvalContext<'mir, 'tcx>;
fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriEvalContext<'mir, 'tcx>;
}
impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
#[inline(always)]