[PATCH] Fix debugging of WOW64 processes

[Hannes Domani]

The new code regarding pending stops only checks for EXCEPTION_BREAKPOINT,
but for WOW64 processes STATUS_WX86_BREAKPOINT is necessary as well.

Also, ignore_first_breakpoint is used now in nat/windows-nat.c as well,
but was not available there.

gdb/ChangeLog:

2020-04-09  Hannes Domani  <ssbssa@yahoo.de>

	* nat/windows-nat.c (STATUS_WX86_BREAKPOINT, STATUS_WX86_SINGLE_STEP):
	Move to...
	* nat/windows-nat.h (STATUS_WX86_BREAKPOINT, STATUS_WX86_SINGLE_STEP):
	... here.
	* windows-nat.c (windows_nat_target::get_windows_debug_event):
	Check for STATUS_WX86_BREAKPOINT.
	(windows_nat_target::wait): Same.
---
 gdb/nat/windows-nat.c | 7 ++++---
 gdb/nat/windows-nat.h | 8 ++++++++
 gdb/windows-nat.c     | 9 ++++++---
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c
index 94e7f572c0..cd7c1d177c 100644
--- a/gdb/nat/windows-nat.c
+++ b/gdb/nat/windows-nat.c
@@ -20,9 +20,6 @@
 #include "nat/windows-nat.h"
 #include "gdbsupport/common-debug.h"
 
-#define STATUS_WX86_BREAKPOINT 0x4000001F
-#define STATUS_WX86_SINGLE_STEP 0x4000001E
-
 namespace windows_nat
 {
 
@@ -44,6 +41,10 @@ DWORD desired_stop_thread_id = -1;
 std::vector<pending_stop> pending_stops;
 EXCEPTION_RECORD siginfo_er;
 
+#ifdef __x86_64__
+bool ignore_first_breakpoint = false;
+#endif
+
 /* Note that 'debug_events' must be locally defined in the relevant
    functions.  */
 #define DEBUG_EVENTS(x)	if (debug_events) debug_printf x
diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index 0597120c21..aea1519672 100644
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -25,6 +25,9 @@
 #include "gdbsupport/gdb_optional.h"
 #include "target/waitstatus.h"
 
+#define STATUS_WX86_BREAKPOINT 0x4000001F
+#define STATUS_WX86_SINGLE_STEP 0x4000001E
+
 namespace windows_nat
 {
 
@@ -202,6 +205,11 @@ extern std::vector<pending_stop> pending_stops;
 /* Contents of $_siginfo */
 extern EXCEPTION_RECORD siginfo_er;
 
+#ifdef __x86_64__
+/* Ignore first breakpoint exception of WOW64 process */
+extern bool ignore_first_breakpoint;
+#endif
+
 /* 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
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 4fddaa3ffa..9ba27c73a1 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -235,7 +235,6 @@ static int saw_create;
 static int open_process_used = 0;
 #ifdef __x86_64__
 static bool wow64_process = false;
-static bool ignore_first_breakpoint = false;
 #endif
 
 /* User options.  */
@@ -1657,7 +1656,9 @@ windows_nat_target::get_windows_debug_event (int pid,
 
       if (current_event.dwDebugEventCode == EXCEPTION_DEBUG_EVENT
 	  && (current_event.u.Exception.ExceptionRecord.ExceptionCode
-	      == EXCEPTION_BREAKPOINT)
+	      == EXCEPTION_BREAKPOINT
+	      || current_event.u.Exception.ExceptionRecord.ExceptionCode
+	      == STATUS_WX86_BREAKPOINT)
 	  && windows_initialization_done)
 	{
 	  ptid_t ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
@@ -1737,7 +1738,9 @@ windows_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
 	      current_windows_thread->stopped_at_software_breakpoint = false;
 	      if (current_event.dwDebugEventCode == EXCEPTION_DEBUG_EVENT
 		  && (current_event.u.Exception.ExceptionRecord.ExceptionCode
-		      == EXCEPTION_BREAKPOINT)
+		      == EXCEPTION_BREAKPOINT
+		      || current_event.u.Exception.ExceptionRecord.ExceptionCode
+		      == STATUS_WX86_BREAKPOINT)
 		  && windows_initialization_done)
 		current_windows_thread->stopped_at_software_breakpoint = true;
 	    }
-- 
2.26.0