* win/configure:

	* win/configure.in: Define HAVE_ALLOCA_GCC_INLINE
	when we detect that no alloca function is found
	in malloc.h and we are compiling with GCC.
	Remove HAVE_NO_ALLOC_DECL define.
	* win/tclWin32Dll.c (TclpCheckStackSpace):
	Don't define alloca as a cdecl function.
	Doing this caused a tricky runtime bug because
	the _alloca function expects the size argument
	to be passed in a register and not on the stack.
	To fix this problem, we use inline ASM when
	compiling with gcc to invoke _alloca with the
	size argument loaded into a register.

4 files changed, 76 insertions, 42 deletions

diff --git a/ChangeLog b/ChangeLog
index 4b3fa79..37fbaef 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2003-01-25  Mo DeJong  <mdejong@users.sourceforge.net>
+
+	* win/configure:
+	* win/configure.in: Define HAVE_ALLOCA_GCC_INLINE
+	when we detect that no alloca function is found
+	in malloc.h and we are compiling with GCC.
+	Remove HAVE_NO_ALLOC_DECL define.
+	* win/tclWin32Dll.c (TclpCheckStackSpace):
+	Don't define alloca as a cdecl function.
+	Doing this caused a tricky runtime bug because
+	the _alloca function expects the size argument
+	to be passed in a register and not on the stack.
+	To fix this problem, we use inline ASM when
+	compiling with gcc to invoke _alloca with the
+	size argument loaded into a register.
+
 2003-01-24  Jeff Hobbs  <jeffh@ActiveState.com>
 
 	* win/tclWinDde.c (Dde_Init): clarified use of tsdPtr.
diff --git a/win/configure b/win/configure
index aae48ca..a5d5bdc 100755
--- a/win/configure
+++ b/win/configure
@@ -1169,14 +1169,21 @@ fi
 
 # Check to see if malloc.h is missing the alloca function
 # declaration. This is known to be a problem with Mingw.
+# If we compiled without the function declaration, it
+# would work but we would get a warning message from gcc.
+# If we add the function declaration ourselves, it
+# would not compile correctly because the _alloca
+# function expects the argument to be passed in a
+# register and not on the stack. Instead, we just
+# call it from inline asm code.
 
 echo $ac_n "checking for alloca declaration in malloc.h""... $ac_c" 1>&6
-echo "configure:1175: checking for alloca declaration in malloc.h" >&5
+echo "configure:1182: checking for alloca declaration in malloc.h" >&5
 if eval "test \"`echo '$''{'tcl_cv_malloc_decl_alloca'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1180 "configure"
+#line 1187 "configure"
 #include "confdefs.h"
 
 #include <malloc.h>
@@ -1190,7 +1197,7 @@ int main() {
 
 ; return 0; }
 EOF
-if { (eval echo configure:1194: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:1201: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   tcl_cv_malloc_decl_alloca=yes
 else
@@ -1204,26 +1211,26 @@ rm -f conftest*
 fi
 
 echo "$ac_t""$tcl_cv_malloc_decl_alloca" 1>&6
-if test "$tcl_cv_malloc_decl_alloca" = "no" ; then
+if test "$tcl_cv_malloc_decl_alloca" = "no" &&
+   test "${GCC}" = "yes" ; then
     cat >> confdefs.h <<\EOF
-#define HAVE_NO_ALLOC_DECL 1
+#define HAVE_ALLOCA_GCC_INLINE 1
 EOF
 
 fi
 
-
 #--------------------------------------------------------------------
 # Determines the correct binary file extension (.o, .obj, .exe etc.)
 #--------------------------------------------------------------------
 
 echo $ac_n "checking for object suffix""... $ac_c" 1>&6
-echo "configure:1221: checking for object suffix" >&5
+echo "configure:1228: checking for object suffix" >&5
 if eval "test \"`echo '$''{'ac_cv_objext'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   rm -f conftest*
 echo 'int i = 1;' > conftest.$ac_ext
-if { (eval echo configure:1227: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:1234: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   for ac_file in conftest.*; do
     case $ac_file in
     *.c) ;;
@@ -1241,19 +1248,19 @@ OBJEXT=$ac_cv_objext
 ac_objext=$ac_cv_objext
 
 echo $ac_n "checking for mingw32 environment""... $ac_c" 1>&6
-echo "configure:1245: checking for mingw32 environment" >&5
+echo "configure:1252: checking for mingw32 environment" >&5
 if eval "test \"`echo '$''{'ac_cv_mingw32'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1250 "configure"
+#line 1257 "configure"
 #include "confdefs.h"
 
 int main() {
 return __MINGW32__;
 ; return 0; }
 EOF
-if { (eval echo configure:1257: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:1264: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   ac_cv_mingw32=yes
 else
@@ -1272,7 +1279,7 @@ test "$ac_cv_mingw32" = yes && MINGW32=yes
 
 
 echo $ac_n "checking for executable suffix""... $ac_c" 1>&6
-echo "configure:1276: checking for executable suffix" >&5
+echo "configure:1283: checking for executable suffix" >&5
 if eval "test \"`echo '$''{'ac_cv_exeext'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1282,7 +1289,7 @@ else
   rm -f conftest*
   echo 'int main () { return 0; }' > conftest.$ac_ext
   ac_cv_exeext=
-  if { (eval echo configure:1286: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; }; then
+  if { (eval echo configure:1293: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; }; then
     for file in conftest.*; do
       case $file in
       *.c | *.o | *.obj) ;;
@@ -1309,7 +1316,7 @@ ac_exeext=$EXEEXT
 
 
     echo $ac_n "checking for building with threads""... $ac_c" 1>&6
-echo "configure:1313: checking for building with threads" >&5
+echo "configure:1320: checking for building with threads" >&5
     # Check whether --enable-threads or --disable-threads was given.
 if test "${enable_threads+set}" = set; then
   enableval="$enable_threads"
@@ -1346,7 +1353,7 @@ EOF
 
 
     echo $ac_n "checking how to build libraries""... $ac_c" 1>&6
-echo "configure:1350: checking how to build libraries" >&5
+echo "configure:1357: checking how to build libraries" >&5
     # Check whether --enable-shared or --disable-shared was given.
 if test "${enable_shared+set}" = set; then
   enableval="$enable_shared"
@@ -1387,7 +1394,7 @@ EOF
     # Step 0: Enable 64 bit support?
 
     echo $ac_n "checking if 64bit support is requested""... $ac_c" 1>&6
-echo "configure:1391: checking if 64bit support is requested" >&5
+echo "configure:1398: checking if 64bit support is requested" >&5
     # Check whether --enable-64bit or --disable-64bit was given.
 if test "${enable_64bit+set}" = set; then
   enableval="$enable_64bit"
@@ -1404,7 +1411,7 @@ fi
     # Extract the first word of "cygpath", so it can be a program name with args.
 set dummy cygpath; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:1408: checking for $ac_word" >&5
+echo "configure:1415: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_CYGPATH'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -1448,9 +1455,9 @@ fi
 	echo "END" >> $conftest
 
 	echo $ac_n "checking for Windows native path bug in windres""... $ac_c" 1>&6
-echo "configure:1452: checking for Windows native path bug in windres" >&5
+echo "configure:1459: checking for Windows native path bug in windres" >&5
 	cyg_conftest=`$CYGPATH $conftest`
-	if { ac_try='$RC -o conftest.res.o $cyg_conftest'; { (eval echo configure:1454: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; } ; then
+	if { ac_try='$RC -o conftest.res.o $cyg_conftest'; { (eval echo configure:1461: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; } ; then
 	    echo "$ac_t""no" 1>&6
 	else
 	    echo "$ac_t""yes" 1>&6
@@ -1469,7 +1476,7 @@ echo "configure:1452: checking for Windows native path bug in windres" >&5
     # set various compiler flags depending on whether we are using gcc or cl
 
     echo $ac_n "checking compiler flags""... $ac_c" 1>&6
-echo "configure:1473: checking compiler flags" >&5
+echo "configure:1480: checking compiler flags" >&5
     if test "${GCC}" = "yes" ; then
 	if test "$do64bit" = "yes" ; then
 	    echo "configure: warning: "64bit mode not supported with GCC on Windows"" 1>&2
@@ -1685,7 +1692,7 @@ echo "configure:1473: checking compiler flags" >&5
 
 
     echo $ac_n "checking for build with symbols""... $ac_c" 1>&6
-echo "configure:1689: checking for build with symbols" >&5
+echo "configure:1696: checking for build with symbols" >&5
     # Check whether --enable-symbols or --disable-symbols was given.
 if test "${enable_symbols+set}" = set; then
   enableval="$enable_symbols"
@@ -1745,7 +1752,7 @@ TCL_DBGX=${DBGX}
 #--------------------------------------------------------------------
 
 echo $ac_n "checking how to run the C preprocessor""... $ac_c" 1>&6
-echo "configure:1749: checking how to run the C preprocessor" >&5
+echo "configure:1756: checking how to run the C preprocessor" >&5
 # On Suns, sometimes $CPP names a directory.
 if test -n "$CPP" && test -d "$CPP"; then
   CPP=
@@ -1760,13 +1767,13 @@ else
   # On the NeXT, cc -E runs the code through the compiler's parser,
   # not just through cpp.
   cat > conftest.$ac_ext <<EOF
-#line 1764 "configure"
+#line 1771 "configure"
 #include "confdefs.h"
 #include <assert.h>
 Syntax Error
 EOF
 ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1770: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+{ (eval echo configure:1777: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
 ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
 if test -z "$ac_err"; then
   :
@@ -1777,13 +1784,13 @@ else
   rm -rf conftest*
   CPP="${CC-cc} -E -traditional-cpp"
   cat > conftest.$ac_ext <<EOF
-#line 1781 "configure"
+#line 1788 "configure"
 #include "confdefs.h"
 #include <assert.h>
 Syntax Error
 EOF
 ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1787: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+{ (eval echo configure:1794: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
 ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
 if test -z "$ac_err"; then
   :
@@ -1794,13 +1801,13 @@ else
   rm -rf conftest*
   CPP="${CC-cc} -nologo -E"
   cat > conftest.$ac_ext <<EOF
-#line 1798 "configure"
+#line 1805 "configure"
 #include "confdefs.h"
 #include <assert.h>
 Syntax Error
 EOF
 ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1804: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+{ (eval echo configure:1811: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
 ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
 if test -z "$ac_err"; then
   :
@@ -1826,17 +1833,17 @@ echo "$ac_t""$CPP" 1>&6
 
 ac_safe=`echo "errno.h" | sed 'y%./+-%__p_%'`
 echo $ac_n "checking for errno.h""... $ac_c" 1>&6
-echo "configure:1830: checking for errno.h" >&5
+echo "configure:1837: checking for errno.h" >&5
 if eval "test \"`echo '$''{'ac_cv_header_$ac_safe'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 1835 "configure"
+#line 1842 "configure"
 #include "confdefs.h"
 #include <errno.h>
 EOF
 ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1840: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+{ (eval echo configure:1847: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
 ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
 if test -z "$ac_err"; then
   rm -rf conftest*
diff --git a/win/configure.in b/win/configure.in
index 0b99959..16591e6 100644
--- a/win/configure.in
+++ b/win/configure.in
@@ -3,7 +3,7 @@
 # generate the file "configure", which is run during Tcl installation
 # to configure the system for the local environment.
 #
-# RCS: @(#) $Id: configure.in,v 1.63 2003/01/24 08:04:28 mdejong Exp $
+# RCS: @(#) $Id: configure.in,v 1.64 2003/01/25 12:48:12 mdejong Exp $
 
 AC_INIT(../generic/tcl.h)
 AC_PREREQ(2.13)
@@ -196,6 +196,13 @@ fi
 
 # Check to see if malloc.h is missing the alloca function
 # declaration. This is known to be a problem with Mingw.
+# If we compiled without the function declaration, it
+# would work but we would get a warning message from gcc.
+# If we add the function declaration ourselves, it
+# would not compile correctly because the _alloca
+# function expects the argument to be passed in a
+# register and not on the stack. Instead, we just
+# call it from inline asm code.
 
 AC_CACHE_CHECK(for alloca declaration in malloc.h,
     tcl_cv_malloc_decl_alloca,
@@ -211,12 +218,12 @@ AC_TRY_COMPILE([
         tcl_cv_malloc_decl_alloca=yes,
         tcl_cv_malloc_decl_alloca=no)
 )
-if test "$tcl_cv_malloc_decl_alloca" = "no" ; then
-    AC_DEFINE(HAVE_NO_ALLOC_DECL, 1,
-            [Defined when alloca decl is missing from malloc.h])
+if test "$tcl_cv_malloc_decl_alloca" = "no" &&
+   test "${GCC}" = "yes" ; then
+    AC_DEFINE(HAVE_ALLOCA_GCC_INLINE, 1,
+            [Defined when gcc should use inline ASM to call alloca.])
 fi
 
-
 #--------------------------------------------------------------------
 # Determines the correct binary file extension (.o, .obj, .exe etc.)
 #--------------------------------------------------------------------
diff --git a/win/tclWin32Dll.c b/win/tclWin32Dll.c
index 1c029f8..13f2a4b 100644
--- a/win/tclWin32Dll.c
+++ b/win/tclWin32Dll.c
@@ -9,16 +9,11 @@
  * 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 1.21 2003/01/24 08:04:29 mdejong Exp $
+ * RCS: @(#) $Id: tclWin32Dll.c,v 1.22 2003/01/25 12:48:12 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.
@@ -395,7 +390,16 @@ TclpCheckStackSpace()
 #else
     __try {
 #endif /* HAVE_NO_SEH */
+#ifdef HAVE_ALLOCA_GCC_INLINE
+    __asm__ __volatile__ (
+            "movl  %0, %%eax" "\n\t"
+            "call  __alloca" "\n\t"
+            :
+            : "i"(TCL_WIN_STACK_THRESHOLD)
+            : "%eax");
+#else
 	alloca(TCL_WIN_STACK_THRESHOLD);
+#endif /* HAVE_ALLOCA_GCC_INLINE */
 	retval = 1;
 #ifdef HAVE_NO_SEH
     __asm__ __volatile__ (