Add target_os_is_unix helper

Author: infrandomness

src/helpers.rs

@@ -895,3 +895,9 @@ impl std::fmt::Display for HexRange {
         write!(f, "[{:#x}..{:#x}]", self.0.start.bytes(), self.0.end().bytes())
     }
 }
+
+/// Helper function used inside the shims of foreign functions to check that
+/// `target_os` is a supported UNIX OS.
+pub fn target_os_is_unix(target_os: &str) -> bool {
+    matches!(target_os, "linux" | "macos")
+}

src/shims/dlsym.rs

@@ -1,6 +1,7 @@
 use rustc_middle::mir;
 use rustc_target::spec::abi::Abi;
 
+use crate::helpers::target_os_is_unix;
 use crate::*;
 use shims::unix::dlsym as unix;
 use shims::windows::dlsym as windows;
@@ -18,7 +19,8 @@ impl Dlsym {
     pub fn from_str<'tcx>(name: &[u8], target_os: &str) -> InterpResult<'tcx, Option<Dlsym>> {
         let name = &*String::from_utf8_lossy(name);
         Ok(match target_os {
-            "linux" | "macos" => unix::Dlsym::from_str(name, target_os)?.map(Dlsym::Posix),
+            target if target_os_is_unix(target) =>
+                unix::Dlsym::from_str(name, target)?.map(Dlsym::Posix),
             "windows" => windows::Dlsym::from_str(name)?.map(Dlsym::Windows),
             os => bug!("dlsym not implemented for target_os {}", os),
         })

src/shims/env.rs

@@ -8,6 +8,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_target::abi::Size;
 
+use crate::helpers::target_os_is_unix;
 use crate::*;
 
 /// Check whether an operation that writes to a target buffer was successful.
@@ -55,7 +56,7 @@ impl<'tcx> EnvVars<'tcx> {
                 };
                 if forward {
                     let var_ptr = match target_os {
-                        "linux" | "macos" =>
+                        target if target_os_is_unix(target) =>
                             alloc_env_var_as_c_str(name.as_ref(), value.as_ref(), ecx)?,
                         "windows" => alloc_env_var_as_wide_str(name.as_ref(), value.as_ref(), ecx)?,
                         unsupported =>

src/shims/foreign_items.rs

@@ -22,7 +22,7 @@ use rustc_target::{
 };
 
 use super::backtrace::EvalContextExt as _;
-use crate::helpers::convert::Truncate;
+use crate::helpers::{convert::Truncate, target_os_is_unix};
 use crate::*;
 
 /// Returned by `emulate_foreign_item_by_name`.
@@ -702,7 +702,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
             // Platform-specific shims
             _ => match this.tcx.sess.target.os.as_ref() {
-                "linux" | "macos" => return shims::unix::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest, ret),
+                target if target_os_is_unix(target) => return shims::unix::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest, ret),
                 "windows" => return shims::windows::foreign_items::EvalContextExt::emulate_foreign_item_by_name(this, link_name, abi, args, dest, ret),
                 target => throw_unsup_format!("the target `{}` is not supported", target),
             }