Improve timezone handling in 'localtime_r()' using 'allocate_bytes()'

Signed-off-by: shamb0 <[email protected]>

src/shims/time.rs

@@ -183,8 +183,6 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         if !matches!(&*this.tcx.sess.target.os, "solaris" | "illumos") {
             // tm_zone represents the timezone value in the form of: +0730, +08, -0730 or -08.
             // This may not be consistent with libc::localtime_r's result.
-            const TZ_MAX_LEN: u64 = 6; // 5 chars max + null terminator
-            static TIMEZONE_PTR: OnceLock<Pointer> = OnceLock::new();
 
             let offset_in_seconds = dt.offset().fix().local_minus_utc();
             let tm_gmtoff = offset_in_seconds;
@@ -201,21 +199,17 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 write!(tm_zone, "{:02}", offset_min).unwrap();
             }
 
-            // Ensure string deduplication by allocating the buffer only once,
-            // even if the function is called multiple times.
-            let tm_zone_ptr = TIMEZONE_PTR.get_or_init(|| {
-                let arg_type = Ty::new_array(this.tcx.tcx, this.tcx.types.u8, TZ_MAX_LEN);
-                let arg_place = this
-                    .allocate(this.layout_of(arg_type).unwrap(), MiriMemoryKind::Machine.into())
-                    .expect("timezone buffer allocation failed");
-                arg_place.ptr()
-            });
-
-            // Write the `tm_zone` string into the allocated buffer.
-            let (written, _) =
-                this.write_os_str_to_c_str(&OsString::from(tm_zone), *tm_zone_ptr, TZ_MAX_LEN)?;
-            assert!(written);
-
+            // Add null terminator for C string compatibility
+            tm_zone.push('\0');
+
+            // Deduplicate and allocate the string.
+            let tm_zone_ptr = this.allocate_bytes(
+                &tm_zone.as_bytes(),
+                Align::ONE,
+                MiriMemoryKind::Machine.into(),
+                Mutability::Not,
+            )?;
+
             // Write the timezone pointer and offset into the result structure.
             this.write_pointer(*tm_zone_ptr, &this.project_field_named(&result, "tm_zone")?)?;
             this.write_int_fields_named(&[("tm_gmtoff", tm_gmtoff.into())], &result)?;