Use appropriate context flags for Wow64 processes

When I implemented debugging of Wow64 processes, I missed that there are
extra ContextFlags defines for them.
It's a bit surprising that the wrong ones actually worked, except that
CONTEXT_EXTENDED_REGISTERS is not available for x86_64, and they are
needed for i686, since that's where the xmm registers are stored.

So this replaces the ContextFlags values with their WOW64_* equivalents.
On gdbserver this also duplicates the fallback logic if the
GetThreadContext call failed with CONTEXT_EXTENDED_REGISTERS.

Fixes these fails:
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm0
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm0
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm1
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm1
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm2
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm2
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm3
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm3
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm4
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm4
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm5
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm5
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm6
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm6
FAIL: gdb.arch/i386-sse.exp: check float contents of %xmm7
FAIL: gdb.arch/i386-sse.exp: check int8 contents of %xmm7
FAIL: gdb.arch/i386-sse.exp: check contents of data[0]
FAIL: gdb.arch/i386-sse.exp: check contents of data[1]
FAIL: gdb.arch/i386-sse.exp: check contents of data[2]
FAIL: gdb.arch/i386-sse.exp: check contents of data[3]
FAIL: gdb.arch/i386-sse.exp: check contents of data[4]
FAIL: gdb.arch/i386-sse.exp: check contents of data[5]
FAIL: gdb.arch/i386-sse.exp: check contents of data[6]
FAIL: gdb.arch/i386-sse.exp: check contents of data[7]

Approved-By: Tom Tromey <tom@tromey.com>

2 files changed, 25 insertions, 9 deletions

diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 37c1f46..abacafe 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -730,7 +730,7 @@ windows_nat_target::fetch_registers (struct regcache *regcache, int r)
 #ifdef __x86_64__
       if (windows_process.wow64_process)
 	{
-	  th->wow64_context.ContextFlags = CONTEXT_DEBUGGER_DR;
+	  th->wow64_context.ContextFlags = WOW64_CONTEXT_ALL;
 	  CHECK (Wow64GetThreadContext (th->h, &th->wow64_context));
 	  /* Copy dr values from that thread.
 	     But only if there were not modified since last stop.
@@ -1290,7 +1290,7 @@ windows_nat_target::windows_continue (DWORD continue_status, int id,
 	  {
 	    if (th->debug_registers_changed)
 	      {
-		th->wow64_context.ContextFlags |= CONTEXT_DEBUG_REGISTERS;
+		th->wow64_context.ContextFlags |= WOW64_CONTEXT_DEBUG_REGISTERS;
 		th->wow64_context.Dr0 = windows_process.dr[0];
 		th->wow64_context.Dr1 = windows_process.dr[1];
 		th->wow64_context.Dr2 = windows_process.dr[2];
diff --git a/gdbserver/win32-i386-low.cc b/gdbserver/win32-i386-low.cc
index 688e012..7898ac1 100644
--- a/gdbserver/win32-i386-low.cc
+++ b/gdbserver/win32-i386-low.cc
@@ -250,14 +250,17 @@ i386_get_thread_context (windows_thread_info *th)
   /* Requesting the CONTEXT_EXTENDED_REGISTERS register set fails if
      the system doesn't support extended registers.  */
   static DWORD extended_registers = CONTEXT_EXTENDED_REGISTERS;
+#ifdef __x86_64__
+  static DWORD wow64_extended_registers = WOW64_CONTEXT_EXTENDED_REGISTERS;
+#endif
 
  again:
 #ifdef __x86_64__
   if (windows_process.wow64_process)
-    th->wow64_context.ContextFlags = (CONTEXT_FULL
-				      | CONTEXT_FLOATING_POINT
-				      | CONTEXT_DEBUG_REGISTERS
-				      | extended_registers);
+    th->wow64_context.ContextFlags = (WOW64_CONTEXT_FULL
+				      | WOW64_CONTEXT_FLOATING_POINT
+				      | WOW64_CONTEXT_DEBUG_REGISTERS
+				      | wow64_extended_registers);
   else
 #endif
     th->context.ContextFlags = (CONTEXT_FULL
@@ -276,10 +279,23 @@ i386_get_thread_context (windows_thread_info *th)
     {
       DWORD e = GetLastError ();
 
-      if (extended_registers && e == ERROR_INVALID_PARAMETER)
+#ifdef __x86_64__
+      if (windows_process.wow64_process)
+	{
+	  if (wow64_extended_registers && e == ERROR_INVALID_PARAMETER)
+	    {
+	      wow64_extended_registers = 0;
+	      goto again;
+	    }
+	}
+      else
+#endif
 	{
-	  extended_registers = 0;
-	  goto again;
+	  if (extended_registers && e == ERROR_INVALID_PARAMETER)
+	    {
+	      extended_registers = 0;
+	      goto again;
+	    }
 	}
 
       error ("GetThreadContext failure %ld\n", (long) e);