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[PATCH 2/2] Send thread names to debugger
- From: Jon Turney <jon dot turney at dronecode dot org dot uk>
- To: cygwin-patches at cygwin dot com
- Cc: Jon Turney <jon dot turney at dronecode dot org dot uk>
- Date: Mon, 22 Aug 2016 19:08:48 +0100
- Subject: [PATCH 2/2] Send thread names to debugger
- Authentication-results: sourceware.org; auth=none
- References: <20160822180848.351616-1-jon.turney@dronecode.org.uk>
GDB since commit 24cdb46e [1] can report and use these names.
Add utility function SetThreadName(), which sends a thread name to the
debugger.
Use that:
- to set the default thread name for main thread and newly created pthreads.
- in pthread_setname_np() for user thread names.
- for helper thread names in cygthread::create()
- for helper threads which are created directly with CreateThread.
Note that there can still be anonymous threads, created by system or
injected DLLs.
[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=24cdb46e9f0a694b4fbc11085e094857f08c0419
---
winsup/cygwin/cygthread.cc | 2 ++
winsup/cygwin/dcrt0.cc | 1 +
winsup/cygwin/exceptions.cc | 2 +-
winsup/cygwin/miscfuncs.cc | 26 ++++++++++++++++++++++++++
winsup/cygwin/miscfuncs.h | 2 ++
winsup/cygwin/net.cc | 1 +
winsup/cygwin/thread.cc | 5 +++++
7 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/winsup/cygwin/cygthread.cc b/winsup/cygwin/cygthread.cc
index b9d706b..4404e4a 100644
--- a/winsup/cygwin/cygthread.cc
+++ b/winsup/cygwin/cygthread.cc
@@ -213,6 +213,8 @@ cygthread::create ()
this, 0, &id);
if (!htobe)
api_fatal ("CreateThread failed for %s - %p<%y>, %E", __name, h, id);
+ else
+ SetThreadName (GetThreadId (htobe), __name);
thread_printf ("created name '%s', thread %p, id %y", __name, h, id);
#ifdef DEBUGGING
terminated = false;
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 2328411..8ddee0c 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -964,6 +964,7 @@ dll_crt0_1 (void *)
if (cp > __progname && ascii_strcasematch (cp, ".exe"))
*cp = '\0';
}
+ SetThreadName (GetCurrentThreadId (), program_invocation_short_name);
(void) xdr_set_vprintf (&cygxdr_vwarnx);
cygwin_finished_initializing = true;
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index d65f56e..0f5a890 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -1288,7 +1288,7 @@ DWORD WINAPI
dumpstack_overflow_wrapper (PVOID arg)
{
cygwin_exception *exc = (cygwin_exception *) arg;
-
+ SetThreadName (GetCurrentThreadId (), "__dumpstack_overflow");
exc->dumpstack ();
return 0;
}
diff --git a/winsup/cygwin/miscfuncs.cc b/winsup/cygwin/miscfuncs.cc
index d0e4bf7..5a63b26 100644
--- a/winsup/cygwin/miscfuncs.cc
+++ b/winsup/cygwin/miscfuncs.cc
@@ -1110,3 +1110,29 @@ wmemcpy: \n\
.seh_endproc \n\
");
#endif
+
+/* Signal the thread name to any attached debugger
+
+ (See "How to: Set a Thread Name in Native Code"
+ https://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx) */
+
+#define MS_VC_EXCEPTION 0x406D1388
+
+void
+SetThreadName(DWORD dwThreadID, const char* threadName)
+{
+ if (!IsDebuggerPresent ())
+ return;
+
+ ULONG_PTR info[] =
+ {
+ 0x1000, /* type, must be 0x1000 */
+ (ULONG_PTR) threadName, /* pointer to threadname */
+ dwThreadID, /* thread ID (+ flags on x86_64) */
+#ifdef __X86__
+ 0, /* flags, must be zero */
+#endif
+ };
+
+ RaiseException (MS_VC_EXCEPTION, 0, sizeof (info)/sizeof (ULONG_PTR), (ULONG_PTR *) &info);
+}
diff --git a/winsup/cygwin/miscfuncs.h b/winsup/cygwin/miscfuncs.h
index a885dcf..5087299 100644
--- a/winsup/cygwin/miscfuncs.h
+++ b/winsup/cygwin/miscfuncs.h
@@ -85,4 +85,6 @@ extern "C" HANDLE WINAPI CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func,
DWORD creation_flags,
LPDWORD thread_id);
+void SetThreadName (DWORD dwThreadID, const char* threadName);
+
#endif /*_MISCFUNCS_H*/
diff --git a/winsup/cygwin/net.cc b/winsup/cygwin/net.cc
index 52b3d98..e4805d3 100644
--- a/winsup/cygwin/net.cc
+++ b/winsup/cygwin/net.cc
@@ -1819,6 +1819,7 @@ get_adapters_addresses (PIP_ADAPTER_ADDRESSES *pa_ret, ULONG family)
The OS allocates stacks bottom up, so chances are good that the new
stack will be located in the lower address area. */
HANDLE thr = CreateThread (NULL, 0, call_gaa, ¶m, 0, NULL);
+ SetThreadName (GetThreadId (thr), "__call_gaa");
if (!thr)
{
debug_printf ("CreateThread: %E");
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index fac801b..1205ce3 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -1992,6 +1992,9 @@ pthread::thread_init_wrapper (void *arg)
_my_tls.sigmask = thread->parent_sigmask;
thread->set_tls_self_pointer ();
+ // Give thread default name
+ SetThreadName (GetCurrentThreadId (), program_invocation_short_name);
+
thread->mutex.lock ();
// if thread is detached force cleanup on exit
@@ -2630,6 +2633,8 @@ pthread_setname_np (pthread_t thread, const char *name)
oldname = thread->attr.name;
thread->attr.name = cp;
+ SetThreadName (GetThreadId (thread->win32_obj_id), thread->attr.name);
+
if (oldname)
free (oldname);
--
2.8.3