basic theading

src/lib.rs

@@ -5,6 +5,8 @@
 #![feature(try_blocks)]
 #![feature(let_else)]
 #![feature(io_error_more)]
+#![feature(int_log)]
+#![feature(variant_count)]
 #![feature(yeet_expr)]
 #![feature(is_some_with)]
 #![feature(nonzero_ops)]

src/shims/tls.rs

@@ -235,7 +235,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn schedule_windows_tls_dtors(&mut self) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
         let active_thread = this.get_active_thread();
-        assert_eq!(this.get_total_thread_count(), 1, "concurrency on Windows is not supported");
+
         // Windows has a special magic linker section that is run on certain events.
         // Instead of searching for that section and supporting arbitrary hooks in there
         // (that would be basically https://github.com/rust-lang/miri/issues/450),
@@ -252,7 +252,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             this.get_ptr_fn(this.scalar_to_ptr(thread_callback)?)?.as_instance()?;
 
         // The signature of this function is `unsafe extern "system" fn(h: c::LPVOID, dwReason: c::DWORD, pv: c::LPVOID)`.
-        let reason = this.eval_path_scalar(&["std", "sys", "windows", "c", "DLL_THREAD_DETACH"])?;
+        let reason = this.eval_windows("c", "DLL_THREAD_DETACH")?;
         this.call_function(
             thread_callback,
             Abi::System { unwind: false },

src/shims/unix/thread.rs

@@ -13,47 +13,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     ) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
 
-        // Create the new thread
-        let new_thread_id = this.create_thread();
-
-        // Write the current thread-id, switch to the next thread later
-        // to treat this write operation as occuring on the current thread.
-        let thread_info_place = this.deref_operand(thread)?;
-        this.write_scalar(
-            Scalar::from_uint(new_thread_id.to_u32(), thread_info_place.layout.size),
-            &thread_info_place.into(),
-        )?;
-
-        // Read the function argument that will be sent to the new thread
-        // before the thread starts executing since reading after the
-        // context switch will incorrectly report a data-race.
-        let fn_ptr = this.read_pointer(start_routine)?;
-        let func_arg = this.read_immediate(arg)?;
-
-        // Finally switch to new thread so that we can push the first stackframe.
-        // After this all accesses will be treated as occuring in the new thread.
-        let old_thread_id = this.set_active_thread(new_thread_id);
-
-        // Perform the function pointer load in the new thread frame.
-        let instance = this.get_ptr_fn(fn_ptr)?.as_instance()?;
-
-        // Note: the returned value is currently ignored (see the FIXME in
-        // pthread_join below) because the Rust standard library does not use
-        // it.
-        let ret_place =
-            this.allocate(this.layout_of(this.tcx.types.usize)?, MiriMemoryKind::Machine.into())?;
-
-        this.call_function(
-            instance,
+        this.start_thread(
+            Some(thread),
+            start_routine,
             Abi::C { unwind: false },
-            &[*func_arg],
-            Some(&ret_place.into()),
-            StackPopCleanup::Root { cleanup: true },
+            arg,
+            this.layout_of(this.tcx.types.usize)?,
         )?;
 
-        // Restore the old active thread frame.
-        this.set_active_thread(old_thread_id);
-
         Ok(0)
     }
 

src/shims/windows/dlsym.rs

@@ -5,11 +5,13 @@ use rustc_target::spec::abi::Abi;
 use log::trace;
 
 use crate::helpers::check_arg_count;
+use crate::shims::windows::handle::Handle;
 use crate::*;
 
 #[derive(Debug, Copy, Clone)]
 pub enum Dlsym {
     NtWriteFile,
+    SetThreadDescription,
 }
 
 impl Dlsym {
@@ -20,6 +22,7 @@ impl Dlsym {
             "GetSystemTimePreciseAsFileTime" => None,
             "SetThreadDescription" => None,
             "NtWriteFile" => Some(Dlsym::NtWriteFile),
+            "SetThreadDescription" => Some(Dlsym::SetThreadDescription),
             _ => throw_unsup_format!("unsupported Windows dlsym: {}", name),
         })
     }
@@ -106,6 +109,22 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     dest,
                 )?;
             }
+            Dlsym::SetThreadDescription => {
+                let [handle, name] = check_arg_count(args)?;
+
+                let name = this.read_wide_str(this.read_pointer(name)?)?;
+
+                let thread =
+                    match Handle::from_scalar(this.read_scalar(handle)?.check_init()?, this)? {
+                        Some(Handle::Thread(thread)) => thread,
+                        Some(Handle::CurrentThread) => this.get_active_thread(),
+                        _ => throw_ub_format!("invalid handle"),
+                    };
+
+                this.set_thread_name_wide(thread, name);
+
+                this.write_null(dest)?;
+            }
         }
 
         trace!("{:?}", this.dump_place(**dest));

src/shims/windows/foreign_items.rs

@@ -1,13 +1,18 @@
 use std::iter;
+use std::time::{Duration, Instant};
 
 use rustc_middle::mir;
 use rustc_span::Symbol;
 use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi;
 
+use crate::thread::Time;
 use crate::*;
 use shims::foreign_items::EmulateByNameResult;
+use shims::windows::handle::{EvalContextExt as _, Handle};
 use shims::windows::sync::EvalContextExt as _;
+use shims::windows::thread::EvalContextExt as _;
+
 use smallvec::SmallVec;
 
 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
@@ -230,6 +235,29 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 let result = this.QueryPerformanceFrequency(lpFrequency)?;
                 this.write_scalar(Scalar::from_i32(result), dest)?;
             }
+            "Sleep" => {
+                let [timeout] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.check_no_isolation("`Sleep`")?;
+
+                let timeout_ms = this.read_scalar(timeout)?.to_u32()?;
+
+                let duration = Duration::from_millis(timeout_ms as u64);
+                let timeout_time = Time::Monotonic(Instant::now().checked_add(duration).unwrap());
+
+                let active_thread = this.get_active_thread();
+                this.block_thread(active_thread);
+
+                this.register_timeout_callback(
+                    active_thread,
+                    timeout_time,
+                    Box::new(move |ecx| {
+                        ecx.unblock_thread(active_thread);
+                        Ok(())
+                    }),
+                );
+            }
 
             // Synchronization primitives
             "AcquireSRWLockExclusive" => {
@@ -325,10 +353,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 // FIXME: we should set last_error, but to what?
                 this.write_null(dest)?;
             }
-            "SwitchToThread" => {
+            // this is only callable from std because we know that std ignores the return value
+            "SwitchToThread" if this.frame_in_std() => {
                 let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
-                // Note that once Miri supports concurrency, this will need to return a nonzero
-                // value if this call does result in switching to another thread.
+
+                this.yield_active_thread();
+
+                // FIXME: this should return a nonzero value if this call does result in switching to another thread.
                 this.write_null(dest)?;
             }
             "GetStdHandle" => {
@@ -340,14 +371,37 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 // std-only shim.
                 this.write_scalar(Scalar::from_machine_isize(which.into(), this), dest)?;
             }
+            "CloseHandle" => {
+                let [handle] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
 
-            // Better error for attempts to create a thread
+                this.CloseHandle(handle)?;
+
+                this.write_scalar(Scalar::from_u32(1), dest)?;
+            }
+
+            // Threading
             "CreateThread" => {
-                let [_, _, _, _, _, _] =
+                let [security, stacksize, start, arg, flags, thread] =
                     this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
 
-                this.handle_unsupported("can't create threads on Windows")?;
-                return Ok(EmulateByNameResult::AlreadyJumped);
+                let thread_id =
+                    this.CreateThread(security, stacksize, start, arg, flags, thread)?;
+
+                this.write_scalar(Handle::Thread(thread_id).to_scalar(this), dest)?;
+            }
+            "WaitForSingleObject" => {
+                let [handle, timeout] =
+                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.WaitForSingleObject(handle, timeout)?;
+
+                this.write_scalar(Scalar::from_u32(0), dest)?;
+            }
+            "GetCurrentThread" => {
+                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
+
+                this.write_scalar(Handle::CurrentThread.to_scalar(this), dest)?;
             }
 
             // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
@@ -385,40 +439,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 // Any non zero value works for the stdlib. This is just used for stack overflows anyway.
                 this.write_scalar(Scalar::from_u32(1), dest)?;
             }
-            | "InitializeCriticalSection"
-            | "EnterCriticalSection"
-            | "LeaveCriticalSection"
-            | "DeleteCriticalSection"
-                if this.frame_in_std() =>
-            {
-                #[allow(non_snake_case)]
-                let [_lpCriticalSection] =
-                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
-                assert_eq!(
-                    this.get_total_thread_count(),
-                    1,
-                    "concurrency on Windows is not supported"
-                );
-                // Nothing to do, not even a return value.
-                // (Windows locks are reentrant, and we have only 1 thread,
-                // so not doing any futher checks here is at least not incorrect.)
-            }
-            "TryEnterCriticalSection" if this.frame_in_std() => {
-                #[allow(non_snake_case)]
-                let [_lpCriticalSection] =
-                    this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
-                assert_eq!(
-                    this.get_total_thread_count(),
-                    1,
-                    "concurrency on Windows is not supported"
-                );
-                // There is only one thread, so this always succeeds and returns TRUE.
-                this.write_scalar(Scalar::from_i32(1), dest)?;
-            }
-            "GetCurrentThread" if this.frame_in_std() => {
-                let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
-                this.write_scalar(Scalar::from_machine_isize(1, this), dest)?;
-            }
             "GetCurrentProcessId" if this.frame_in_std() => {
                 let [] = this.check_shim(abi, Abi::System { unwind: false }, link_name, args)?;
                 let result = this.GetCurrentProcessId()?;