Use GetThreadDescription on Windows

Windows 10 introduced SetThreadDescription and GetThreadDescription, a
simpler way to set a thread's name.  This changes gdb and gdbserver to
use this convention when it is available.

This is part of PR win32/29050.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29050

diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c
index 9fdef463760623896d559de706808120df975b56..bd1b94591456884476cb382236eb7617c13221f4 100644 (file)
--- a/gdb/nat/windows-nat.c
+++ b/gdb/nat/windows-nat.c
@@ -58,6 +58,10 @@ Wow64GetThreadSelectorEntry_ftype *Wow64GetThreadSelectorEntry;
 #endif
 GenerateConsoleCtrlEvent_ftype *GenerateConsoleCtrlEvent;
 
+#define GetThreadDescription dyn_GetThreadDescription
+typedef HRESULT WINAPI (GetThreadDescription_ftype) (HANDLE, PWSTR *);
+static GetThreadDescription_ftype *GetThreadDescription;
+
 /* Note that 'debug_events' must be locally defined in the relevant
    functions.  */
 #define DEBUG_EVENTS(fmt, ...) \
@@ -106,6 +110,29 @@ windows_thread_info::resume ()
   suspended = 0;
 }
 
+const char *
+windows_thread_info::thread_name ()
+{
+  if (GetThreadDescription != nullptr)
+    {
+      PWSTR value;
+      HRESULT result = GetThreadDescription (h, &value);
+      if (SUCCEEDED (result))
+       {
+         size_t needed = wcstombs (nullptr, value, 0);
+         if (needed != (size_t) -1)
+           {
+             name.reset ((char *) xmalloc (needed));
+             if (wcstombs (name.get (), value, needed) == (size_t) -1)
+               name.reset ();
+           }
+         LocalFree (value);
+       }
+    }
+
+  return name.get ();
+}
+
 /* Return the name of the DLL referenced by H at ADDRESS.  UNICODE
    determines what sort of string is read from the inferior.  Returns
    the name of the DLL, or NULL on error.  If a name is returned, it
@@ -662,6 +689,7 @@ initialize_loadable ()
       GPA (hm, Wow64GetThreadSelectorEntry);
 #endif
       GPA (hm, GenerateConsoleCtrlEvent);
+      GPA (hm, GetThreadDescription);
     }
 
   /* Set variables to dummy versions of these processes if the function
@@ -718,6 +746,15 @@ initialize_loadable ()
        OpenProcessToken = bad;
     }
 
+  /* On some versions of Windows, this function is only available in
+     KernelBase.dll, not kernel32.dll.  */
+  if (GetThreadDescription == nullptr)
+    {
+      hm = LoadLibrary (TEXT ("KernelBase.dll"));
+      if (hm)
+       GPA (hm, GetThreadDescription);
+    }
+
 #undef GPA
 
   return result;

diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index 522e267176dd04f2bf2c3bad2f350c22f9614bfe..29fd0a3a69bcb6f1fb7e884606965ecba51f7c67 100644 (file)
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -51,6 +51,11 @@ struct windows_thread_info
   /* Resume the thread if it has been suspended.  */
   void resume ();
 
+  /* Return the thread's name, or nullptr if not known.  The name is
+     stored in this thread and is guaranteed to live until at least
+     the next call.  */
+  const char *thread_name ();
+
   /* The Win32 thread identifier.  */
   DWORD tid;
 

diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 581eb47e7baee97741bd4f19678dd6b40c7644dc..1068558cd2111ebd06d99d136e240e5bf32fa83f 100644 (file)
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -2997,8 +2997,10 @@ windows_nat_target::get_ada_task_ptid (long lwp, ULONGEST thread)
 const char *
 windows_nat_target::thread_name (struct thread_info *thr)
 {
-  return windows_process.thread_rec (thr->ptid,
-                                    DONT_INVALIDATE_CONTEXT)->name.get ();
+  windows_thread_info *th
+    = windows_process.thread_rec (thr->ptid,
+                                 DONT_INVALIDATE_CONTEXT);
+  return th->thread_name ();
 }
 
 

diff --git a/gdbserver/win32-low.cc b/gdbserver/win32-low.cc
index 16c13f32d7791920331e447fb5e9aa9b5ef024c6..afeed1a98810f0d7636c8d8da00d4aa3bdc83b92 100644 (file)
--- a/gdbserver/win32-low.cc
+++ b/gdbserver/win32-low.cc
@@ -1508,7 +1508,7 @@ win32_process_target::thread_name (ptid_t thread)
   windows_thread_info *th
     = windows_process.thread_rec (current_thread_ptid (),
                                  DONT_INVALIDATE_CONTEXT);
-  return th->name.get ();
+  return th->thread_name ();
 }
 
 /* The win32 target ops object.  */