From: Pedro Alves <palves@redhat.com>
Date: Tue, 17 Nov 2015 15:17:45 +0000 (+0000)
Subject: [C++/mingw] Simplify first chance exception handling
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=95824559df96a53ddeccbaacd91617f83c8d52cd;p=binutils-gdb.git

[C++/mingw] Simplify first chance exception handling

Building in C++ errors out with:

../../src/gdb/windows-nat.c: In function 'int get_windows_debug_event(target_ops*, int, target_waitstatus*)':
../../src/gdb/windows-nat.c:1503:13: warning: invalid conversion from 'int' to 'gdb_signal' [-fpermissive]
    last_sig = 1;
             ^
../../src/gdb/windows-nat.c:1533:43: warning: invalid conversion from 'int' to 'gdb_signal' [-fpermissive]
  windows_resume (ops, minus_one_ptid, 0, 1);
                                           ^
../../src/gdb/windows-nat.c:1228:1: warning:   initializing argument 4 of 'void windows_resume(target_ops*, ptid_t, int, gdb_signal)' [-fpermissive]
 windows_resume (struct target_ops *ops,
 ^

Looking at the code, I can't figure out why we treat first chance
exceptions any different here.

AFAICS, we set last_sig to 1, and then call windows_resume passing
signal==1, so the DBG_EXCEPTION_NOT_HANDLED code path in win32_resume
is taken:

~~~
  if (sig != GDB_SIGNAL_0)
    {
      if (current_event.dwDebugEventCode != EXCEPTION_DEBUG_EVENT)
	{
	  OUTMSG (("Cannot continue with signal %d here.\n", sig));
	}
      else if (sig == last_sig)
	continue_status = DBG_EXCEPTION_NOT_HANDLED;
      else
	OUTMSG (("Can only continue with recieved signal %d.\n", last_sig));
    }
~~~

Fix this by removing this special casing.  gdbserver also goes
straight to continuing with DBG_EXCEPTION_NOT_HANDLED, AFAICS.

gdb/ChangeLog:
2015-11-17  Pedro Alves  <palves@redhat.com>

	* windows-nat.c (handle_exception): Return 0 for first chance
	exceptions.
	(get_windows_debug_event): Adjust.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4639df48280..fbfe4aded67 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2015-11-17  Pedro Alves  <palves@redhat.com>
+
+	* windows-nat.c (handle_exception): Return 0 for first chance
+	exceptions.
+	(get_windows_debug_event): Adjust.
+
 2015-11-17  Pedro Alves  <palves@redhat.com>
 
 	* windows-nat.c (xslate): Use GDB_SIGNAL_UNKNOWN instead of -1 as
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index cce10f8818e..a7132d62105 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -1124,7 +1124,7 @@ handle_exception (struct target_waitstatus *ourstatus)
     default:
       /* Treat unhandled first chance exceptions specially.  */
       if (current_event.u.Exception.dwFirstChance)
-	return -1;
+	return 0;
       printf_unfiltered ("gdb: unknown target exception 0x%08x at %s\n",
 	(unsigned) current_event.u.Exception.ExceptionRecord.ExceptionCode,
 	host_address_to_string (
@@ -1491,19 +1491,10 @@ get_windows_debug_event (struct target_ops *ops,
 		     "EXCEPTION_DEBUG_EVENT"));
       if (saw_create != 1)
 	break;
-      switch (handle_exception (ourstatus))
-	{
-	case 0:
-	  continue_status = DBG_EXCEPTION_NOT_HANDLED;
-	  break;
-	case 1:
-	  thread_id = current_event.dwThreadId;
-	  break;
-	case -1:
-	  last_sig = 1;
-	  continue_status = -1;
-	  break;
-	}
+      if (handle_exception (ourstatus))
+	thread_id = current_event.dwThreadId;
+      else
+	continue_status = DBG_EXCEPTION_NOT_HANDLED;
       break;
 
     case OUTPUT_DEBUG_STRING_EVENT:	/* Message from the kernel.  */
@@ -1529,10 +1520,7 @@ get_windows_debug_event (struct target_ops *ops,
 
   if (!thread_id || saw_create != 1)
     {
-      if (continue_status == -1)
-	windows_resume (ops, minus_one_ptid, 0, 1);
-      else
-	CHECK (windows_continue (continue_status, -1, 0));
+      CHECK (windows_continue (continue_status, -1, 0));
     }
   else
     {