Rollup merge of #44374 - jsheard:threadname, r=alexcrichton

Implement named threads on Windows (v2)

https://msdn.microsoft.com/en-us/library/windows/desktop/mt774976(v=vs.85).aspx

Windows 10 version 1607 finally added a sensible API for naming threads, so we can now implement named threads without having to use MSVC compiler extensions like before. VS2017s debugger and the WPA profiler already use this API where available, but other tools may need some time to catch up.

![thread](https://user-images.githubusercontent.com/3153547/30133438-c92a3cda-934b-11e7-9668-915d53e8d860.png)

diff --git a/src/libstd/sys/windows/c.rs b/src/libstd/sys/windows/c.rs
index 7dfcc996e18e2e8202b7f6c061800ea005356204..9535ddfe5cada5143c22cee3dbf9a1f9a48ba84a 100644 (file)
--- a/src/libstd/sys/windows/c.rs
+++ b/src/libstd/sys/windows/c.rs
@@ -32,6 +32,7 @@
 pub type HANDLE = LPVOID;
 pub type HINSTANCE = HANDLE;
 pub type HMODULE = HINSTANCE;
+pub type HRESULT = LONG;
 pub type BOOL = c_int;
 pub type BYTE = u8;
 pub type BOOLEAN = BYTE;
@@ -197,6 +198,8 @@ fn clone(&self) -> Self { *self }
 pub const ERROR_IO_PENDING: DWORD = 997;
 pub const ERROR_TIMEOUT: DWORD = 0x5B4;
 
+pub const E_NOTIMPL: HRESULT = 0x80004001u32 as HRESULT;
+
 pub const INVALID_HANDLE_VALUE: HANDLE = !0 as HANDLE;
 
 pub const FACILITY_NT_BIT: DWORD = 0x1000_0000;
@@ -1163,8 +1166,8 @@ pub fn select(nfds: c_int,
                   timeout: *const timeval) -> c_int;
 }
 
-// Functions that aren't available on Windows XP, but we still use them and just
-// provide some form of a fallback implementation.
+// Functions that aren't available on every version of Windows that we support,
+// but we still use them and just provide some form of a fallback implementation.
 compat_fn! {
     kernel32:
 
@@ -1182,6 +1185,10 @@ pub fn GetFinalPathNameByHandleW(_hFile: HANDLE,
     pub fn SetThreadStackGuarantee(_size: *mut c_ulong) -> BOOL {
         SetLastError(ERROR_CALL_NOT_IMPLEMENTED as DWORD); 0
     }
+    pub fn SetThreadDescription(hThread: HANDLE,
+                                lpThreadDescription: LPCWSTR) -> HRESULT {
+        SetLastError(ERROR_CALL_NOT_IMPLEMENTED as DWORD); E_NOTIMPL
+    }
     pub fn SetFileInformationByHandle(_hFile: HANDLE,
                     _FileInformationClass: FILE_INFO_BY_HANDLE_CLASS,
                     _lpFileInformation: LPVOID,

diff --git a/src/libstd/sys/windows/thread.rs b/src/libstd/sys/windows/thread.rs
index 6aea9d1fb560f118379fe7d0c4c8dbd7c26ece2a..c47baaa2434025fe4476fd8ac4b6dc3431c31dad 100644 (file)
--- a/src/libstd/sys/windows/thread.rs
+++ b/src/libstd/sys/windows/thread.rs
@@ -19,6 +19,8 @@
 use sys_common::thread::*;
 use time::Duration;
 
+use super::to_u16s;
+
 pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024;
 
 pub struct Thread {
@@ -55,11 +57,12 @@ extern "system" fn thread_start(main: *mut c_void) -> c::DWORD {
         }
     }
 
-    pub fn set_name(_name: &CStr) {
-        // Windows threads are nameless
-        // The names in MSVC debugger are obtained using a "magic" exception,
-        // which requires a use of MS C++ extensions.
-        // See https://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
+    pub fn set_name(name: &CStr) {
+        if let Ok(utf8) = name.to_str() {
+            if let Ok(utf16) = to_u16s(utf8) {
+                unsafe { c::SetThreadDescription(c::GetCurrentThread(), utf16.as_ptr()); };
+            };
+        };
     }
 
     pub fn join(self) {