* win/configure: Regen.

	* win/configure.in:
	* win/tclWin32Dll.c (TclpCheckStackSpace): Rework
	the SEH exception handler logic to avoid using
	the stack since alloca will modify the stack.
	This was causing a nasty bug that would set the
	exception handler to 0 because it tried to pop
	the previous exception handler off the top of
	the stack.

1 files changed, 20 insertions, 7 deletions

diff --git a/win/tclWin32Dll.c b/win/tclWin32Dll.c
index ac9e8cd..1c029f8 100644
--- a/win/tclWin32Dll.c
+++ b/win/tclWin32Dll.c
@@ -9,11 +9,16 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclWin32Dll.c,v 1.20 2003/01/16 19:01:59 mdejong Exp $
+ * RCS: @(#) $Id: tclWin32Dll.c,v 1.21 2003/01/24 08:04:29 mdejong Exp $
  */
 
 #include "tclWinInt.h"
 
+#if defined(HAVE_NO_ALLOC_DECL)
+void*  __cdecl _alloca(size_t size);
+#define alloca _alloca
+#endif /* HAVE_NO_ALLOC_DECL */
+
 /*
  * The following data structures are used when loading the thunking 
  * library for execing child processes under Win32s.
@@ -40,6 +45,9 @@ static int platformId;		/* Running under NT, or 95/98? */
 #ifdef HAVE_NO_SEH
 static void *ESP;
 static void *EBP;
+static void* HANDLER[2];
+static void* NEW_HANDLER = &(HANDLER[0]);
+static void* OLD_HANDLER = &(HANDLER[1]);
 #endif /* HAVE_NO_SEH */
 
 /*
@@ -378,9 +386,12 @@ TclpCheckStackSpace()
             "movl  %ebp, _EBP");
 
     __asm__ __volatile__ (
-            "pushl $__except_checkstackspace_handler" "\n\t"
-            "pushl %fs:0" "\n\t"
-            "mov   %esp, %fs:0");
+            "movl  %fs:0, %eax" "\n\t"
+            "movl  %eax, _OLD_HANDLER" "\n\t"
+            "movl  __except_checkstackspace_handler, %eax" "\n\t"
+            "movl  %eax, _NEW_HANDLER" "\n\t"
+            "movl  _HANDLER, %eax" "\n\t"
+            "movl  %eax, %fs:0");
 #else
     __try {
 #endif /* HAVE_NO_SEH */
@@ -395,9 +406,8 @@ TclpCheckStackSpace()
 
     __asm__ __volatile__ (
             "checkstackspace_pop:" "\n\t"
-            "mov   (%esp), %eax" "\n\t"
-            "mov   %eax, %fs:0" "\n\t"
-            "add   $8, %esp");
+            "mov   _OLD_HANDLER, %eax"  "\n\t"
+            "mov   %eax, %fs:0");
 #else
     } __except (EXCEPTION_EXECUTE_HANDLER) {}
 #endif /* HAVE_NO_SEH */
@@ -625,6 +635,9 @@ static void squelch_warnings()
     ptr = _except_checkstackspace_handler;
     ESP = 0;
     EBP = 0;
+    OLD_HANDLER = 0;
+    NEW_HANDLER = 0;
+    HANDLER[0] = 0;
     squelch_warnings();
 }
 #endif /* HAVE_NO_SEH */