x86-win32 "shared" attribute

[Mumit Khan]

The following patch introduces a new attribute for x86-win32, "shared",
that allows a section/segment to be shareable among all running copies
of the executable.

For example, the declaration:
  
  int __attribute__((section("my_shared_data"),shared) foo = 0;

will put foo in a named section called "my_shared_data" and make it 
shareable among all running copies of the executable.

Sat Aug  7 00:38:21 1999  Mumit Khan  <khan@xraylith.wisc.edu>
	
	* i386/winnt.c (i386_pe_valid_decl_attribute_p): Recognize
	shared as a valid attribute.
	* i386/cygwin.h (ASM_OUTPUT_SECTION): Handle shared attribute.

Index: gcc/config/i386/winnt.c
===================================================================
RCS file: /homes/khan/src/CVSROOT/gcc-2.95/gcc/config/i386/winnt.c,v
retrieving revision 1.3
diff -u -3 -p -r1.3 winnt.c
--- gcc/config/i386/winnt.c	1999/06/21 04:40:30	1.3
+++ gcc/config/i386/winnt.c	1999/08/07 04:04:31
@@ -56,6 +56,8 @@ i386_pe_valid_decl_attribute_p (decl, at
 	return 1;
       if (is_attribute_p ("dllimport", attr))
 	return 1;
+      if (is_attribute_p ("shared", attr))
+	return TREE_CODE (decl) == VAR_DECL;
     }
 
   return i386_valid_decl_attribute_p (decl, attributes, attr, args);
Index: gcc/config/i386/cygwin.h
===================================================================
RCS file: /homes/khan/src/CVSROOT/gcc-2.95/gcc/config/i386/cygwin.h,v
retrieving revision 1.3
diff -u -3 -p -r1.3 cygwin.h
--- gcc/config/i386/cygwin.h	1999/07/04 18:23:41	1.3
+++ gcc/config/i386/cygwin.h	1999/08/07 04:03:35
@@ -404,7 +404,14 @@ do {									\
   else if (DECL && DECL_READONLY_SECTION (DECL, RELOC))			\
     type = SECT_RO, mode = "";						\
   else									\
-    type = SECT_RW, mode = "w";						\
+    {									\
+      type = SECT_RW;							\
+      if (TREE_CODE (DECL) == VAR_DECL					\
+          && lookup_attribute ("shared", DECL_MACHINE_ATTRIBUTES (DECL))) \
+        mode = "ws";							\
+      else								\
+        mode = "w";							\
+    }									\
 									\
   if (s == 0)								\
     {									\

Regards,
Mumit