remove try_from_ptr_sized_operand

Author: pvdrz

src/helpers.rs

@@ -1,7 +1,5 @@
 use std::{mem, iter};
 use std::ffi::OsStr;
-use std::convert::{ TryFrom, TryInto };
-use std::num::TryFromIntError;
 
 use syntax::source_map::DUMMY_SP;
 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX};
@@ -482,25 +480,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         self.eval_context_mut().memory.write_bytes(scalar, bytes.iter().copied().chain(iter::once(0u8)))?;
         Ok(true)
     }
-
-    // Converts an operand with a machine `isize` into the desired integer type using `TryInto`.
-    // This function is useful when reading syscall related operands which are delivered as pointer
-    // sized operands.
-    fn try_from_ptr_sized_operand<T: TryFrom<i64, Error=TryFromIntError>>(
-        &mut self,
-        operand: OpTy<'tcx, Tag>,
-    ) -> InterpResult<'tcx, T> {
-        let this = self.eval_context_mut();
-
-        this.read_scalar(operand)?
-            .to_machine_isize(&*this.tcx)?
-            .try_into()
-            .map_err(|e| err_unsup_format!(
-                "Failed to convert pointer sized operand to integer: {}",
-                e
-            ).into())
-    }
-
 }
 
 #[cfg(target_os = "unix")]

src/shims/fs.rs

@@ -305,16 +305,27 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
         let path: PathBuf = this.read_os_str_from_c_str(pathname_scalar)?.into();
         // `flags` should be a `c_int` but the `syscall` function provides an `isize`.
-        let flags: i32 = this.try_from_ptr_sized_operand(flags_op)?;
-
+        let flags: i32 = this
+            .read_scalar(flags_op)?
+            .to_machine_isize(&*this.tcx)?
+            .try_into()
+            .map_err(|e| err_unsup_format!(
+                "Failed to convert pointer sized operand to integer: {}",
+                e
+            ))?;
+        // `dirfd` should be a `c_int` but the `syscall` function provides an `isize`.
+        let dirfd: i32 = this
+            .read_scalar(dirfd_op)?
+            .to_machine_isize(&*this.tcx)?
+            .try_into()
+            .map_err(|e| err_unsup_format!(
+                "Failed to convert pointer sized operand to integer: {}",
+                e
+            ))?;
         // we only support interpreting `path` as an absolute directory or as a directory relative
         // to `dirfd` when the latter is `AT_FDCWD`. Other behavior is specified but it cannot be
         // tested from `libstd`. If you found this error, please open an issue reporting it.
-
-        // `dirfd` should be a `c_int` but the `syscall` function provides an `isize`.
-        if !(path.is_absolute()
-            || this.try_from_ptr_sized_operand::<i32>(dirfd_op)?
-                == this.eval_libc_i32("AT_FDCWD")?)
+        if !(path.is_absolute() || dirfd == this.eval_libc_i32("AT_FDCWD")?)
         {
             throw_unsup_format!(
                 "Using statx with a file descriptor different from `AT_FDCWD` is not supported"