diff mbox

[review] Share handle_exception

Message ID gerrit.1574788288000.I4e6e0d17b868cd51964c273fb28ec066fea6b767@gnutoolchain-gerrit.osci.io
State New
Headers show

Commit Message

Simon Marchi (Code Review) Nov. 26, 2019, 5:11 p.m. UTC
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................

Share handle_exception

Both gdb and gdbserver have a "handle_exception" function, the bulk of
which is shared between the two implementations.  This patch arranges
for the entire thing to be moved into nat/windows-nat.c, with the
differences handled by callbacks.  This patch introduces one more
callback to make this possible.

gdb/ChangeLog
2019-11-26  Tom Tromey  <tromey@adacore.com>

	* windows-nat.c (MS_VC_EXCEPTION): Move to nat/windows-nat.c.
	(handle_exception_result): Move to nat/windows-nat.h.
	(DEBUG_EXCEPTION_SIMPLE): Remove.
	(windows_nat::handle_ms_vc_exception): New function.
	(handle_exception): Move to nat/windows-nat.c.
	(get_windows_debug_event): Update.
	* nat/windows-nat.h (handle_ms_vc_exception): Declare.
	(handle_exception_result): Move from windows-nat.c.
	(handle_exception): Declare.
	* nat/windows-nat.c (MS_VC_EXCEPTION, handle_exception): Move from
	windows-nat.c.

gdb/gdbserver/ChangeLog
2019-11-26  Tom Tromey  <tromey@adacore.com>

	* win32-low.c (handle_exception): Remove.
	(windows_nat::handle_ms_vc_exception): New function.
	(get_child_debug_event): Add "continue_status" parameter.
	Update.
	(win32_wait): Update.

Change-Id: I4e6e0d17b868cd51964c273fb28ec066fea6b767
---
M gdb/ChangeLog
M gdb/gdbserver/ChangeLog
M gdb/gdbserver/win32-low.c
M gdb/nat/windows-nat.c
M gdb/nat/windows-nat.h
M gdb/windows-nat.c
6 files changed, 245 insertions(+), 283 deletions(-)

Comments

Simon Marchi (Code Review) Nov. 29, 2019, 8:03 p.m. UTC | #1
Pedro Alves has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................


Patch Set 1:

I'm confused since gerrit thinks this is a new patch instead of a revision of:

 https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/425

Did you consider not having the new callbacks and instead install target_ops::thread_name on gdbserver too?
Simon Marchi (Code Review) Nov. 29, 2019, 8:05 p.m. UTC | #2
Simon Marchi has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................


Patch Set 1:

> Patch Set 1:
> 
> I'm confused since gerrit thinks this is a new patch instead of a revision of:

It seems like the Change-Id has been changed between the two revisions.
Simon Marchi (Code Review) Nov. 29, 2019, 8:51 p.m. UTC | #3
Pedro Alves has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................


Patch Set 1:

> Patch Set 1:
> > Patch Set 1:
> > I'm confused since gerrit thinks this is a new patch instead of a revision of:
> It seems like the Change-Id has been changed between the two revisions.

AFAICS, it's "I4e6e0d17b868cd51964c273fb28ec066fea6b767" for both.
Simon Marchi (Code Review) Nov. 29, 2019, 8:57 p.m. UTC | #4
Simon Marchi has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................


Patch Set 1:

> Patch Set 1:
> 
> > Patch Set 1:
> > > Patch Set 1:
> > > I'm confused since gerrit thinks this is a new patch instead of a revision of:
> > It seems like the Change-Id has been changed between the two revisions.
> 
> AFAICS, it's "I4e6e0d17b868cd51964c273fb28ec066fea6b767" for both.

Ah, there are two in change 425, I4e6e0d17b868cd51964c273fb28ec066fea6b767 is above the ChangeLog entries and I2efe53c78f5a8e28381e539505f1b703967933c4 is below.  I guess I2efe53c78f5a8e28381e539505f1b703967933c4 was the "real" one but Tom kept I4e6e0d17b868cd51964c273fb28ec066fea6b767.

In the old Gerrit interface you could see what the Change-Id as parsed by Gerrit was, but I don't see a similar field here.
Simon Marchi (Code Review) Dec. 4, 2019, 4:19 p.m. UTC | #5
Tom Tromey has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................


Patch Set 1:

> Patch Set 1:
> 
> I'm confused since gerrit thinks this is a new patch instead of a revision of:
> 
>  https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/425
> 
> Did you consider not having the new callbacks and instead install target_ops::thread_name on gdbserver too?

I tried today.  There's no shared target_read_string API, and I don't want
to add any more things to this series than are strictly required -- it's already
too long.
Simon Marchi (Code Review) Dec. 4, 2019, 4:32 p.m. UTC | #6
Pedro Alves has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/716
......................................................................


Patch Set 1: Code-Review+2

> Patch Set 1:
> > Patch Set 1:
> > Did you consider not having the new callbacks and instead install target_ops::thread_name on gdbserver too?
> 
> I tried today.  There's no shared target_read_string API, and I don't want
> to add any more things to this series than are strictly required -- it's already
> too long.

Fair enough.
diff mbox

Patch

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 221a6e7..d2caa25 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,19 @@ 
 2019-11-26  Tom Tromey  <tromey@adacore.com>
 
+	* windows-nat.c (MS_VC_EXCEPTION): Move to nat/windows-nat.c.
+	(handle_exception_result): Move to nat/windows-nat.h.
+	(DEBUG_EXCEPTION_SIMPLE): Remove.
+	(windows_nat::handle_ms_vc_exception): New function.
+	(handle_exception): Move to nat/windows-nat.c.
+	(get_windows_debug_event): Update.
+	* nat/windows-nat.h (handle_ms_vc_exception): Declare.
+	(handle_exception_result): Move from windows-nat.c.
+	(handle_exception): Declare.
+	* nat/windows-nat.c (MS_VC_EXCEPTION, handle_exception): Move from
+	windows-nat.c.
+
+2019-11-26  Tom Tromey  <tromey@adacore.com>
+
 	* windows-nat.c (exception_count, event_count): Remove.
 	(handle_exception, get_windows_debug_event)
 	(do_initial_windows_stuff): Update.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 5c4c580..8ca754b 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,13 @@ 
 2019-11-26  Tom Tromey  <tromey@adacore.com>
 
+	* win32-low.c (handle_exception): Remove.
+	(windows_nat::handle_ms_vc_exception): New function.
+	(get_child_debug_event): Add "continue_status" parameter.
+	Update.
+	(win32_wait): Update.
+
+2019-11-26  Tom Tromey  <tromey@adacore.com>
+
 	* win32-low.c (windows_nat::handle_load_dll): Rename from
 	handle_load_dll.  No longer static.
 	(windows_nat::handle_unload_dll): Rename from handle_unload_dll.
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 3fcd2a6..ba49dd9 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -1143,114 +1143,6 @@ 
 }
 
 static void
-handle_exception (struct target_waitstatus *ourstatus)
-{
-  DWORD code = current_event.u.Exception.ExceptionRecord.ExceptionCode;
-
-  ourstatus->kind = TARGET_WAITKIND_STOPPED;
-
-  switch (code)
-    {
-    case EXCEPTION_ACCESS_VIOLATION:
-      OUTMSG2 (("EXCEPTION_ACCESS_VIOLATION"));
-      ourstatus->value.sig = GDB_SIGNAL_SEGV;
-      break;
-    case STATUS_STACK_OVERFLOW:
-      OUTMSG2 (("STATUS_STACK_OVERFLOW"));
-      ourstatus->value.sig = GDB_SIGNAL_SEGV;
-      break;
-    case STATUS_FLOAT_DENORMAL_OPERAND:
-      OUTMSG2 (("STATUS_FLOAT_DENORMAL_OPERAND"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
-      OUTMSG2 (("EXCEPTION_ARRAY_BOUNDS_EXCEEDED"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_INEXACT_RESULT:
-      OUTMSG2 (("STATUS_FLOAT_INEXACT_RESULT"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_INVALID_OPERATION:
-      OUTMSG2 (("STATUS_FLOAT_INVALID_OPERATION"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_OVERFLOW:
-      OUTMSG2 (("STATUS_FLOAT_OVERFLOW"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_STACK_CHECK:
-      OUTMSG2 (("STATUS_FLOAT_STACK_CHECK"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_UNDERFLOW:
-      OUTMSG2 (("STATUS_FLOAT_UNDERFLOW"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_DIVIDE_BY_ZERO:
-      OUTMSG2 (("STATUS_FLOAT_DIVIDE_BY_ZERO"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_INTEGER_DIVIDE_BY_ZERO:
-      OUTMSG2 (("STATUS_INTEGER_DIVIDE_BY_ZERO"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_INTEGER_OVERFLOW:
-      OUTMSG2 (("STATUS_INTEGER_OVERFLOW"));
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case EXCEPTION_BREAKPOINT:
-      OUTMSG2 (("EXCEPTION_BREAKPOINT"));
-      ourstatus->value.sig = GDB_SIGNAL_TRAP;
-#ifdef _WIN32_WCE
-      /* Remove the initial breakpoint.  */
-      check_breakpoints ((CORE_ADDR) (long) current_event
-			 .u.Exception.ExceptionRecord.ExceptionAddress);
-#endif
-      break;
-    case DBG_CONTROL_C:
-      OUTMSG2 (("DBG_CONTROL_C"));
-      ourstatus->value.sig = GDB_SIGNAL_INT;
-      break;
-    case DBG_CONTROL_BREAK:
-      OUTMSG2 (("DBG_CONTROL_BREAK"));
-      ourstatus->value.sig = GDB_SIGNAL_INT;
-      break;
-    case EXCEPTION_SINGLE_STEP:
-      OUTMSG2 (("EXCEPTION_SINGLE_STEP"));
-      ourstatus->value.sig = GDB_SIGNAL_TRAP;
-      break;
-    case EXCEPTION_ILLEGAL_INSTRUCTION:
-      OUTMSG2 (("EXCEPTION_ILLEGAL_INSTRUCTION"));
-      ourstatus->value.sig = GDB_SIGNAL_ILL;
-      break;
-    case EXCEPTION_PRIV_INSTRUCTION:
-      OUTMSG2 (("EXCEPTION_PRIV_INSTRUCTION"));
-      ourstatus->value.sig = GDB_SIGNAL_ILL;
-      break;
-    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
-      OUTMSG2 (("EXCEPTION_NONCONTINUABLE_EXCEPTION"));
-      ourstatus->value.sig = GDB_SIGNAL_ILL;
-      break;
-    default:
-      if (current_event.u.Exception.dwFirstChance)
-	{
-	  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
-	  return;
-	}
-      OUTMSG2 (("gdbserver: unknown target exception 0x%08x at 0x%s",
-	    (unsigned) current_event.u.Exception.ExceptionRecord.ExceptionCode,
-	    phex_nz ((uintptr_t) current_event.u.Exception.ExceptionRecord.
-	    ExceptionAddress, sizeof (uintptr_t))));
-      ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
-      break;
-    }
-  OUTMSG2 (("\n"));
-  last_sig = ourstatus->value.sig;
-}
-
-
-static void
 suspend_one_thread (thread_info *thread)
 {
   windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
@@ -1282,15 +1174,25 @@ 
 }
 #endif
 
+/* See nat/windows-nat.h.  */
+
+bool
+windows_nat::handle_ms_vc_exception (const EXCEPTION_RECORD *rec)
+{
+  return false;
+}
+
 /* Get the next event from the child.  */
 
 static int
-get_child_debug_event (struct target_waitstatus *ourstatus)
+get_child_debug_event (DWORD *continue_status,
+		       struct target_waitstatus *ourstatus)
 {
   ptid_t ptid;
 
   last_sig = GDB_SIGNAL_0;
   ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
+  *continue_status = DBG_CONTINUE;
 
   /* Check if GDB sent us an interrupt request.  */
   check_remote_input_interrupt_request ();
@@ -1457,7 +1359,9 @@ 
 		"for pid=%u tid=%x\n",
 		(unsigned) current_event.dwProcessId,
 		(unsigned) current_event.dwThreadId));
-      handle_exception (ourstatus);
+      if (handle_exception (ourstatus, debug_threads)
+	  == HANDLE_EXCEPTION_UNHANDLED)
+	*continue_status = DBG_EXCEPTION_NOT_HANDLED;
       break;
 
     case OUTPUT_DEBUG_STRING_EVENT:
@@ -1504,7 +1408,8 @@ 
 
   while (1)
     {
-      if (!get_child_debug_event (ourstatus))
+      DWORD continue_status;
+      if (!get_child_debug_event (&continue_status, ourstatus))
 	continue;
 
       switch (ourstatus->kind)
@@ -1527,7 +1432,7 @@ 
 	  /* fall-through */
 	case TARGET_WAITKIND_SPURIOUS:
 	  /* do nothing, just continue */
-	  child_continue (DBG_CONTINUE, -1);
+	  child_continue (continue_status, -1);
 	  break;
 	}
     }
diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c
index 57bbae1..1d76f37 100644
--- a/gdb/nat/windows-nat.c
+++ b/gdb/nat/windows-nat.c
@@ -18,6 +18,7 @@ 
 
 #include "gdbsupport/common-defs.h"
 #include "nat/windows-nat.h"
+#include "gdbsupport/common-debug.h"
 
 namespace windows_nat
 {
@@ -137,4 +138,159 @@ 
   return buf;
 }
 
+/* The exception thrown by a program to tell the debugger the name of
+   a thread.  The exception record contains an ID of a thread and a
+   name to give it.  This exception has no documented name, but MSDN
+   dubs it "MS_VC_EXCEPTION" in one code example.  */
+#define MS_VC_EXCEPTION 0x406d1388
+
+handle_exception_result
+handle_exception (struct target_waitstatus *ourstatus, bool debug_exceptions)
+{
+#define DEBUG_EXCEPTION_SIMPLE(x)       if (debug_exceptions) \
+  debug_printf ("gdb: Target exception %s at %s\n", x, \
+    host_address_to_string (\
+      current_event.u.Exception.ExceptionRecord.ExceptionAddress))
+
+  EXCEPTION_RECORD *rec = &current_event.u.Exception.ExceptionRecord;
+  DWORD code = rec->ExceptionCode;
+  handle_exception_result result = HANDLE_EXCEPTION_HANDLED;
+
+  ourstatus->kind = TARGET_WAITKIND_STOPPED;
+
+  /* Record the context of the current thread.  */
+  thread_rec (ptid_t (current_event.dwProcessId, current_event.dwThreadId, 0),
+	      DONT_SUSPEND);
+
+  switch (code)
+    {
+    case EXCEPTION_ACCESS_VIOLATION:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ACCESS_VIOLATION");
+      ourstatus->value.sig = GDB_SIGNAL_SEGV;
+#ifdef __CYGWIN__
+      {
+	/* See if the access violation happened within the cygwin DLL
+	   itself.  Cygwin uses a kind of exception handling to deal
+	   with passed-in invalid addresses.  gdb should not treat
+	   these as real SEGVs since they will be silently handled by
+	   cygwin.  A real SEGV will (theoretically) be caught by
+	   cygwin later in the process and will be sent as a
+	   cygwin-specific-signal.  So, ignore SEGVs if they show up
+	   within the text segment of the DLL itself.  */
+	const char *fn;
+	CORE_ADDR addr = (CORE_ADDR) (uintptr_t) rec->ExceptionAddress;
+
+	if ((!cygwin_exceptions && (addr >= cygwin_load_start
+				    && addr < cygwin_load_end))
+	    || (find_pc_partial_function (addr, &fn, NULL, NULL)
+		&& startswith (fn, "KERNEL32!IsBad")))
+	  return HANDLE_EXCEPTION_UNHANDLED;
+      }
+#endif
+      break;
+    case STATUS_STACK_OVERFLOW:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_STACK_OVERFLOW");
+      ourstatus->value.sig = GDB_SIGNAL_SEGV;
+      break;
+    case STATUS_FLOAT_DENORMAL_OPERAND:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DENORMAL_OPERAND");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ARRAY_BOUNDS_EXCEEDED");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_FLOAT_INEXACT_RESULT:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INEXACT_RESULT");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_FLOAT_INVALID_OPERATION:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INVALID_OPERATION");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_FLOAT_OVERFLOW:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_OVERFLOW");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_FLOAT_STACK_CHECK:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_STACK_CHECK");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_FLOAT_UNDERFLOW:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_UNDERFLOW");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_FLOAT_DIVIDE_BY_ZERO:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DIVIDE_BY_ZERO");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_INTEGER_DIVIDE_BY_ZERO:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_DIVIDE_BY_ZERO");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case STATUS_INTEGER_OVERFLOW:
+      DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_OVERFLOW");
+      ourstatus->value.sig = GDB_SIGNAL_FPE;
+      break;
+    case EXCEPTION_BREAKPOINT:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_BREAKPOINT");
+      ourstatus->value.sig = GDB_SIGNAL_TRAP;
+#ifdef _WIN32_WCE
+      /* Remove the initial breakpoint.  */
+      check_breakpoints ((CORE_ADDR) (long) current_event
+			 .u.Exception.ExceptionRecord.ExceptionAddress);
+#endif
+      break;
+    case DBG_CONTROL_C:
+      DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_C");
+      ourstatus->value.sig = GDB_SIGNAL_INT;
+      break;
+    case DBG_CONTROL_BREAK:
+      DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_BREAK");
+      ourstatus->value.sig = GDB_SIGNAL_INT;
+      break;
+    case EXCEPTION_SINGLE_STEP:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_SINGLE_STEP");
+      ourstatus->value.sig = GDB_SIGNAL_TRAP;
+      break;
+    case EXCEPTION_ILLEGAL_INSTRUCTION:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ILLEGAL_INSTRUCTION");
+      ourstatus->value.sig = GDB_SIGNAL_ILL;
+      break;
+    case EXCEPTION_PRIV_INSTRUCTION:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_PRIV_INSTRUCTION");
+      ourstatus->value.sig = GDB_SIGNAL_ILL;
+      break;
+    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
+      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_NONCONTINUABLE_EXCEPTION");
+      ourstatus->value.sig = GDB_SIGNAL_ILL;
+      break;
+    case MS_VC_EXCEPTION:
+      DEBUG_EXCEPTION_SIMPLE ("MS_VC_EXCEPTION");
+      if (handle_ms_vc_exception (rec))
+	{
+	  ourstatus->value.sig = GDB_SIGNAL_TRAP;
+	  result = HANDLE_EXCEPTION_IGNORED;
+	  break;
+	}
+	/* treat improperly formed exception as unknown */
+	/* FALLTHROUGH */
+    default:
+      /* Treat unhandled first chance exceptions specially.  */
+      if (current_event.u.Exception.dwFirstChance)
+	return HANDLE_EXCEPTION_UNHANDLED;
+      debug_printf ("gdb: unknown target exception 0x%08x at %s\n",
+	(unsigned) current_event.u.Exception.ExceptionRecord.ExceptionCode,
+	host_address_to_string (
+	  current_event.u.Exception.ExceptionRecord.ExceptionAddress));
+      ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
+      break;
+    }
+
+  last_sig = ourstatus->value.sig;
+  return result;
+
+#undef DEBUG_EXCEPTION_SIMPLE
+}
+
 }
diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index 78d0421..5fd6174 100644
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -133,6 +133,16 @@ 
 
 extern void handle_unload_dll ();
 
+/* Handle MS_VC_EXCEPTION when processing a stop.  MS_VC_EXCEPTION is
+   somewhat undocumented but is used to tell the debugger the name of
+   a thread.
+
+   Return true if the exception was handled; return false otherwise.
+
+   This function must be supplied by the embedding application.  */
+
+extern bool handle_ms_vc_exception (const EXCEPTION_RECORD *rec);
+
 
 /* Currently executing process */
 extern HANDLE current_process_handle;
@@ -193,6 +203,16 @@ 
    get_image_name.  */
 extern const char *get_image_name (HANDLE h, void *address, int unicode);
 
+typedef enum
+{
+  HANDLE_EXCEPTION_UNHANDLED = 0,
+  HANDLE_EXCEPTION_HANDLED,
+  HANDLE_EXCEPTION_IGNORED
+} handle_exception_result;
+
+extern handle_exception_result handle_exception
+  (struct target_waitstatus *ourstatus, bool debug_exceptions);
+
 }
 
 #endif
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index c046f91..8c690b6 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -182,19 +182,6 @@ 
 static int windows_initialization_done;
 #define DR6_CLEAR_VALUE 0xffff0ff0
 
-/* The exception thrown by a program to tell the debugger the name of
-   a thread.  The exception record contains an ID of a thread and a
-   name to give it.  This exception has no documented name, but MSDN
-   dubs it "MS_VC_EXCEPTION" in one code example.  */
-#define MS_VC_EXCEPTION 0x406d1388
-
-typedef enum
-{
-  HANDLE_EXCEPTION_UNHANDLED = 0,
-  HANDLE_EXCEPTION_HANDLED,
-  HANDLE_EXCEPTION_IGNORED
-} handle_exception_result;
-
 /* The string sent by cygwin when it processes a signal.
    FIXME: This should be in a cygwin include file.  */
 #ifndef _CYGWIN_SIGNAL_STRING
@@ -1067,173 +1054,45 @@ 
     }
 }
 
-#define DEBUG_EXCEPTION_SIMPLE(x)       if (debug_exceptions) \
-  printf_unfiltered ("gdb: Target exception %s at %s\n", x, \
-    host_address_to_string (\
-      current_event.u.Exception.ExceptionRecord.ExceptionAddress))
+/* See nat/windows-nat.h.  */
 
-static handle_exception_result
-handle_exception (struct target_waitstatus *ourstatus)
+bool
+windows_nat::handle_ms_vc_exception (const EXCEPTION_RECORD *rec)
 {
-  EXCEPTION_RECORD *rec = &current_event.u.Exception.ExceptionRecord;
-  DWORD code = rec->ExceptionCode;
-  handle_exception_result result = HANDLE_EXCEPTION_HANDLED;
-
-  ourstatus->kind = TARGET_WAITKIND_STOPPED;
-
-  /* Record the context of the current thread.  */
-  thread_rec (ptid_t (current_event.dwProcessId, current_event.dwThreadId, 0),
-	      DONT_SUSPEND);
-
-  switch (code)
+  if (rec->NumberParameters >= 3
+      && (rec->ExceptionInformation[0] & 0xffffffff) == 0x1000)
     {
-    case EXCEPTION_ACCESS_VIOLATION:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ACCESS_VIOLATION");
-      ourstatus->value.sig = GDB_SIGNAL_SEGV;
-#ifdef __CYGWIN__
-      {
-	/* See if the access violation happened within the cygwin DLL
-	   itself.  Cygwin uses a kind of exception handling to deal
-	   with passed-in invalid addresses.  gdb should not treat
-	   these as real SEGVs since they will be silently handled by
-	   cygwin.  A real SEGV will (theoretically) be caught by
-	   cygwin later in the process and will be sent as a
-	   cygwin-specific-signal.  So, ignore SEGVs if they show up
-	   within the text segment of the DLL itself.  */
-	const char *fn;
-	CORE_ADDR addr = (CORE_ADDR) (uintptr_t) rec->ExceptionAddress;
+      DWORD named_thread_id;
+      windows_thread_info *named_thread;
+      CORE_ADDR thread_name_target;
 
-	if ((!cygwin_exceptions && (addr >= cygwin_load_start
-				    && addr < cygwin_load_end))
-	    || (find_pc_partial_function (addr, &fn, NULL, NULL)
-		&& startswith (fn, "KERNEL32!IsBad")))
-	  return HANDLE_EXCEPTION_UNHANDLED;
-      }
-#endif
-      break;
-    case STATUS_STACK_OVERFLOW:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_STACK_OVERFLOW");
-      ourstatus->value.sig = GDB_SIGNAL_SEGV;
-      break;
-    case STATUS_FLOAT_DENORMAL_OPERAND:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DENORMAL_OPERAND");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ARRAY_BOUNDS_EXCEEDED");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_INEXACT_RESULT:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INEXACT_RESULT");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_INVALID_OPERATION:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INVALID_OPERATION");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_OVERFLOW:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_OVERFLOW");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_STACK_CHECK:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_STACK_CHECK");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_UNDERFLOW:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_UNDERFLOW");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_FLOAT_DIVIDE_BY_ZERO:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DIVIDE_BY_ZERO");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_INTEGER_DIVIDE_BY_ZERO:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_DIVIDE_BY_ZERO");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case STATUS_INTEGER_OVERFLOW:
-      DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_OVERFLOW");
-      ourstatus->value.sig = GDB_SIGNAL_FPE;
-      break;
-    case EXCEPTION_BREAKPOINT:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_BREAKPOINT");
-      ourstatus->value.sig = GDB_SIGNAL_TRAP;
-      break;
-    case DBG_CONTROL_C:
-      DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_C");
-      ourstatus->value.sig = GDB_SIGNAL_INT;
-      break;
-    case DBG_CONTROL_BREAK:
-      DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_BREAK");
-      ourstatus->value.sig = GDB_SIGNAL_INT;
-      break;
-    case EXCEPTION_SINGLE_STEP:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_SINGLE_STEP");
-      ourstatus->value.sig = GDB_SIGNAL_TRAP;
-      break;
-    case EXCEPTION_ILLEGAL_INSTRUCTION:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ILLEGAL_INSTRUCTION");
-      ourstatus->value.sig = GDB_SIGNAL_ILL;
-      break;
-    case EXCEPTION_PRIV_INSTRUCTION:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_PRIV_INSTRUCTION");
-      ourstatus->value.sig = GDB_SIGNAL_ILL;
-      break;
-    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
-      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_NONCONTINUABLE_EXCEPTION");
-      ourstatus->value.sig = GDB_SIGNAL_ILL;
-      break;
-    case MS_VC_EXCEPTION:
-      if (rec->NumberParameters >= 3
-	  && (rec->ExceptionInformation[0] & 0xffffffff) == 0x1000)
+      thread_name_target = rec->ExceptionInformation[1];
+      named_thread_id = (DWORD) (0xffffffff & rec->ExceptionInformation[2]);
+
+      if (named_thread_id == (DWORD) -1)
+	named_thread_id = current_event.dwThreadId;
+
+      named_thread = thread_rec (ptid_t (current_event.dwProcessId,
+					 named_thread_id, 0),
+				 DONT_INVALIDATE_CONTEXT);
+      if (named_thread != NULL)
 	{
-	  DWORD named_thread_id;
-	  windows_thread_info *named_thread;
-	  CORE_ADDR thread_name_target;
+	  int thread_name_len;
+	  gdb::unique_xmalloc_ptr<char> thread_name;
 
-	  DEBUG_EXCEPTION_SIMPLE ("MS_VC_EXCEPTION");
-
-	  thread_name_target = rec->ExceptionInformation[1];
-	  named_thread_id = (DWORD) (0xffffffff & rec->ExceptionInformation[2]);
-
-	  if (named_thread_id == (DWORD) -1)
-	    named_thread_id = current_event.dwThreadId;
-
-	  named_thread = thread_rec (ptid_t (current_event.dwProcessId,
-					     named_thread_id, 0),
-				     DONT_INVALIDATE_CONTEXT);
-	  if (named_thread != NULL)
+	  thread_name_len = target_read_string (thread_name_target,
+						&thread_name, 1025, NULL);
+	  if (thread_name_len > 0)
 	    {
-	      int thread_name_len;
-	      gdb::unique_xmalloc_ptr<char> thread_name;
-
-	      thread_name_len = target_read_string (thread_name_target,
-						    &thread_name, 1025, NULL);
-	      if (thread_name_len > 0)
-		{
-		  thread_name.get ()[thread_name_len - 1] = '\0';
-		  named_thread->name = std::move (thread_name);
-		}
+	      thread_name.get ()[thread_name_len - 1] = '\0';
+	      named_thread->name = std::move (thread_name);
 	    }
-	  ourstatus->value.sig = GDB_SIGNAL_TRAP;
-	  result = HANDLE_EXCEPTION_IGNORED;
-	  break;
 	}
-	/* treat improperly formed exception as unknown */
-	/* FALLTHROUGH */
-    default:
-      /* Treat unhandled first chance exceptions specially.  */
-      if (current_event.u.Exception.dwFirstChance)
-	return HANDLE_EXCEPTION_UNHANDLED;
-      printf_unfiltered ("gdb: unknown target exception 0x%08x at %s\n",
-	(unsigned) current_event.u.Exception.ExceptionRecord.ExceptionCode,
-	host_address_to_string (
-	  current_event.u.Exception.ExceptionRecord.ExceptionAddress));
-      ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
-      break;
+
+      return true;
     }
-  last_sig = ourstatus->value.sig;
-  return result;
+
+  return false;
 }
 
 /* Resume thread specified by ID, or all artificially suspended
@@ -1644,7 +1503,7 @@ 
 		     "EXCEPTION_DEBUG_EVENT"));
       if (saw_create != 1)
 	break;
-      switch (handle_exception (ourstatus))
+      switch (handle_exception (ourstatus, debug_exceptions))
 	{
 	case HANDLE_EXCEPTION_UNHANDLED:
 	default: