Auto merge of #3517 - RalfJung:env-vars, r=RalfJung

env: split up Windows and Unix environment variable handling

On Windows, manage them entirely outside the AM state; this also means we no longer report any data races for environment variable memory.

Fixes rust-lang/rust#124411

src/machine.rs

@@ -31,7 +31,7 @@ use rustc_target::spec::abi::Abi;
 
 use crate::{
     concurrency::{data_race, weak_memory},
-    shims::unix::FdTable,
+    shims::unix,
     *,
 };
 
@@ -439,8 +439,7 @@ pub struct MiriMachine<'mir, 'tcx> {
     /// Ptr-int-cast module global data.
     pub alloc_addresses: alloc_addresses::GlobalState,
 
-    /// Environment variables set by `setenv`.
-    /// Miri does not expose env vars from the host to the emulated program.
+    /// Environment variables.
     pub(crate) env_vars: EnvVars<'tcx>,
 
     /// Return place of the main function.
@@ -465,9 +464,9 @@ pub struct MiriMachine<'mir, 'tcx> {
     pub(crate) validate: bool,
 
     /// The table of file descriptors.
-    pub(crate) fds: shims::unix::FdTable,
+    pub(crate) fds: unix::FdTable,
     /// The table of directory descriptors.
-    pub(crate) dirs: shims::unix::DirTable,
+    pub(crate) dirs: unix::DirTable,
 
     /// This machine's monotone clock.
     pub(crate) clock: Clock,
@@ -642,7 +641,7 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
             tls: TlsData::default(),
             isolated_op: config.isolated_op,
             validate: config.validate,
-            fds: FdTable::new(config.mute_stdout_stderr),
+            fds: unix::FdTable::new(config.mute_stdout_stderr),
             dirs: Default::default(),
             layouts,
             threads: ThreadManager::default(),