* win/tclWin32Dll.c (TclpCheckStackSpace, squelch_warnings):

	* win/tclWinChan.c (Tcl_MakeFileChannel, squelch_warnings):
	* win/tclWinFCmd.c (DoRenameFile, DoCopyFile, squelch_warnings):
	Re-implement inline ASM SEH handlers for gcc.
	The esp and ebp registers are now saved on the
	stack instead of in global variables so that
	the code is thread safe. Add additional checks
	when TCL_MEM_DEBUG is defined to be sure the
	values were recovered from the stack properly.
	Remove squelch_warnings functions and add
	a dummy call in the handler methods to squelch
	compiler warnings.

1 files changed, 51 insertions, 41 deletions

diff --git a/win/tclWin32Dll.c b/win/tclWin32Dll.c
index 13f2a4b..62d9e1c 100644
--- a/win/tclWin32Dll.c
+++ b/win/tclWin32Dll.c
@@ -9,7 +9,7 @@
  * 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 1.22 2003/01/25 12:48:12 mdejong Exp $
+ * RCS: @(#) $Id: tclWin32Dll.c,v 1.23 2003/01/25 14:11:32 mdejong Exp $
  */
 
 #include "tclWinInt.h"
@@ -37,13 +37,14 @@ typedef VOID (WINAPI UTUNREGISTER)(HANDLE hModule);
 static HINSTANCE hInstance;	/* HINSTANCE of this DLL. */
 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 */
+#if defined(HAVE_NO_SEH) && defined(TCL_MEM_DEBUG)
+static void *INITIAL_ESP,
+            *INITIAL_EBP,
+            *INITIAL_HANDLER,
+            *RESTORED_ESP,
+            *RESTORED_EBP,
+            *RESTORED_HANDLER;
+#endif /* HAVE_NO_SEH && TCL_MEM_DEBUG */
 
 /*
  * The following function tables are used to dispatch to either the
@@ -376,17 +377,21 @@ TclpCheckStackSpace()
      */
 
 #ifdef HAVE_NO_SEH
+# ifdef TCL_MEM_DEBUG
     __asm__ __volatile__ (
-            "movl  %esp, _ESP" "\n\t"
-            "movl  %ebp, _EBP");
+            "movl %%esp,  %0" "\n\t"
+            "movl %%ebp,  %1" "\n\t"
+            "movl %%fs:0, %2" "\n\t"
+            : "=m"(INITIAL_ESP),
+              "=m"(INITIAL_EBP),
+              "=r"(INITIAL_HANDLER) );
+# endif /* TCL_MEM_DEBUG */
 
     __asm__ __volatile__ (
-            "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");
+            "pushl %ebp" "\n\t"
+            "pushl $__except_checkstackspace_handler" "\n\t"
+            "pushl %fs:0" "\n\t"
+            "movl  %esp, %fs:0");
 #else
     __try {
 #endif /* HAVE_NO_SEH */
@@ -403,15 +408,36 @@ TclpCheckStackSpace()
 	retval = 1;
 #ifdef HAVE_NO_SEH
     __asm__ __volatile__ (
-            "jmp   checkstackspace_pop" "\n"
-            "checkstackspace_reentry:" "\n\t"
-            "movl  _ESP, %esp" "\n\t"
-            "movl  _EBP, %ebp");
+            "movl %%fs:0, %%esp" "\n\t"
+            "jmp  checkstackspace_pop" "\n"
+        "checkstackspace_reentry:" "\n\t"
+            "movl %%fs:0, %%eax" "\n\t"
+            "movl 0x8(%%eax), %%esp" "\n\t"
+            "movl 0x8(%%esp), %%ebp" "\n"
+        "checkstackspace_pop:" "\n\t"
+            "movl (%%esp), %%eax" "\n\t"
+            "movl %%eax, %%fs:0" "\n\t"
+            "add  $12, %%esp" "\n\t"
+            :
+            :
+            : "%eax");
 
+# ifdef TCL_MEM_DEBUG
     __asm__ __volatile__ (
-            "checkstackspace_pop:" "\n\t"
-            "mov   _OLD_HANDLER, %eax"  "\n\t"
-            "mov   %eax, %fs:0");
+            "movl  %%esp,  %0" "\n\t"
+            "movl  %%ebp,  %1" "\n\t"
+            "movl  %%fs:0, %2" "\n\t"
+            : "=m"(RESTORED_ESP),
+              "=m"(RESTORED_EBP),
+              "=r"(RESTORED_HANDLER) );
+
+    if (INITIAL_ESP != RESTORED_ESP)
+        panic("ESP restored incorrectly");
+    if (INITIAL_EBP != RESTORED_EBP)
+        panic("EBP restored incorrectly");
+    if (INITIAL_HANDLER != RESTORED_HANDLER)
+        panic("HANDLER restored incorrectly");
+# endif /* TCL_MEM_DEBUG */
 #else
     } __except (EXCEPTION_EXECUTE_HANDLER) {}
 #endif /* HAVE_NO_SEH */
@@ -433,6 +459,8 @@ _except_checkstackspace_handler(
 {
     __asm__ __volatile__ (
             "jmp checkstackspace_reentry");
+    /* Nuke compiler warning about unused static function */
+    _except_checkstackspace_handler(NULL, NULL, NULL, NULL);
     return 0; /* Function does not return */
 }
 #endif /* HAVE_NO_SEH */
@@ -627,21 +655,3 @@ Tcl_WinTCharToUtf(string, len, dsPtr)
     return Tcl_ExternalToUtfDString(tclWinTCharEncoding, 
 	    (CONST char *) string, len, dsPtr);
 }
-
-#ifdef HAVE_NO_SEH
-/*
- * This method exists only to stop the compiler from emitting
- * warnings about variables and methods accessed only from asm.
- */
-static void squelch_warnings()
-{
-    void *ptr;
-    ptr = _except_checkstackspace_handler;
-    ESP = 0;
-    EBP = 0;
-    OLD_HANDLER = 0;
-    NEW_HANDLER = 0;
-    HANDLER[0] = 0;
-    squelch_warnings();
-}
-#endif /* HAVE_NO_SEH */