Re: gcc 2.8.0 is broken on linux/x86 and more bug

[hjl at lucon dot org (H.J. Lu)]

The good news is turn off address-off fixes the bug. The bad news
is I can tell from the asm code what is wrong, but it is hard
to generate a small test case and you may have to look at the
asm code directly to verify the bug if you cannot compile glibc 2.1
on Linux/x86.

__register_frame () change in gcc 2.8.0 causes a big problem.
Since __register_frame () called in crtbegin.o is in libgcc2.c and
gcc -shared includes crtbegin.o and -lgcc, any libc.so built by
previous gcc has __register_frame () in libc.so. Now the ABI for
__register_frame () is changed, that is a big mess for Linux since
shared libraries are used a lot. When the ABI of a function in
shared library is changed like this, it doesn't work too well.

Here is the patch. It should apply to both gcc 2.8.0 and egcs.

Thanks.


H.J.
----
Mon Dec  8 15:42:20 1997  H.J. Lu  (hjl@gnu.org)

	* crtstuff.c (__register_frame): Changed to __register_frame_new.
	(__deregister_frame): Changed to __deregister_frame_new.
	* frame.c: Ditto.
	* frame.h: Ditto.
	* collect2.c: Ditto.

	* frame.c (__register_frame_table): Changed to
	__register_frame_table_new.
	* collect2.c: Ditto.

	* frame.c (__register_frame_new, __register_frame_table_new,
	__deregister_frame_new): Added.
	* frame.h: Ditto.

Index: crtstuff.c
===================================================================
RCS file: /home/work/cvs/gnu/egcs/gcc/crtstuff.c,v
retrieving revision 1.1.1.4
diff -u -r1.1.1.4 crtstuff.c
--- crtstuff.c	1997/12/08 17:04:06	1.1.1.4
+++ crtstuff.c	1997/12/08 23:26:29
@@ -142,7 +142,7 @@
     }
 
 #ifdef EH_FRAME_SECTION_ASM_OP
-  __deregister_frame (__EH_FRAME_BEGIN__);
+  __deregister_frame_new (__EH_FRAME_BEGIN__);
 #endif
   completed = 1;
 }
@@ -170,7 +170,7 @@
 frame_dummy ()
 {
   static struct object object;
-  __register_frame (__EH_FRAME_BEGIN__, &object);
+  __register_frame_new (__EH_FRAME_BEGIN__, &object);
 }
 
 static void
@@ -254,7 +254,7 @@
     (*p) ();
 
 #ifdef EH_FRAME_SECTION_ASM_OP
-  __deregister_frame (__EH_FRAME_BEGIN__);
+  __deregister_frame_new (__EH_FRAME_BEGIN__);
 #endif
 }
 #endif
@@ -395,7 +396,7 @@
   func_ptr *p;
 #ifdef EH_FRAME_SECTION_ASM_OP
   static struct oobject object;
-  __register_frame (__EH_FRAME_BEGIN__, &object);
+  __register_frame_new (__EH_FRAME_BEGIN__, &object);
 #endif
   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
     (*p) ();
Index: frame.c
===================================================================
RCS file: /home/work/cvs/gnu/egcs/gcc/frame.c,v
retrieving revision 1.1.1.6
diff -u -r1.1.1.6 frame.c
--- frame.c	1997/12/08 17:04:32	1.1.1.6
+++ frame.c	1997/12/08 23:29:53
@@ -501,7 +501,7 @@
 /* Called from crtbegin.o to register the unwind info for an object.  */
 
 void
-__register_frame (void *begin, struct object *ob)
+__register_frame_new (void *begin, struct object *ob)
 {
   ob->fde_begin = begin;
 
@@ -513,12 +513,19 @@
   objects = ob;
 }
 
+void
+__register_frame (void *begin)
+{
+  struct object *ob = (struct object *) malloc (sizeof (struct object));
+  __register_frame_new (begin, ob);
+}
+
 /* Similar, but BEGIN is actually a pointer to a table of unwind entries
    for different translation units.  Called from the file generated by
    collect2.  */
 
 void
-__register_frame_table (void *begin, struct object *ob)
+__register_frame_table_new (void *begin, struct object *ob)
 {
   ob->fde_begin = begin;
   ob->fde_array = begin;
@@ -530,10 +537,17 @@
   objects = ob;
 }
 
+void
+__register_frame_table (void *begin)
+{
+  struct object *ob = (struct object *) malloc (sizeof (struct object));
+  __register_frame_table_new (begin, ob);
+}
+
 /* Called from crtend.o to deregister the unwind info for an object.  */
 
-void
-__deregister_frame (void *begin)
+void *
+__deregister_frame_new (void *begin)
 {
   struct object **p = &objects;
 
@@ -548,11 +562,17 @@
 	  if (ob->pc_begin)
 	    free (ob->fde_array);
 
-	  return;
+	  return (void *) ob;
 	}
       p = &((*p)->next);
     }
   abort ();
+}
+
+void
+__deregister_frame (void *begin)
+{
+  free (__deregister_frame_new (begin));
 }
 
 /* Called from __throw to find the registers to restore for a given
Index: frame.h
===================================================================
RCS file: /home/work/cvs/gnu/egcs/gcc/frame.h,v
retrieving revision 1.1.1.2
diff -u -r1.1.1.2 frame.h
--- frame.h	1997/12/08 17:04:33	1.1.1.2
+++ frame.h	1997/12/08 23:31:02
@@ -37,11 +37,16 @@
 /* Called either from crtbegin.o or a static constructor to register the
    unwind info for an object or translation unit, respectively.  */
 
-extern void __register_frame (void *, struct object *);
+extern void __register_frame_new (void *, struct object *);
+extern void __register_frame (void *);
 
 /* Called from crtend.o to deregister the unwind info for an object.  */
 
+extern void * __deregister_frame_new (void *);
 extern void __deregister_frame (void *);
+
+extern void __register_frame_table_new (void *, struct object *);
+extern void __register_frame_table (void *);
 
 /* Called from __throw to find the registers to restore for a given
    PC_TARGET.  The caller should allocate a local variable of `struct
Index: collect2.c
===================================================================
RCS file: /home/work/cvs/gnu/egcs/gcc/collect2.c,v
retrieving revision 1.1.1.4
diff -u -r1.1.1.4 collect2.c
--- collect2.c	1997/12/08 17:04:00	1.1.1.4
+++ collect2.c	1997/12/12 02:41:38
@@ -1790,16 +1790,16 @@
       fprintf (stream, "  struct object *next;\n");
       fprintf (stream, "};\n");
 
-      fprintf (stream, "extern void __register_frame_table (void *, struct object *);\n");
-      fprintf (stream, "extern void __deregister_frame (void *);\n");
+      fprintf (stream, "extern void __register_frame_table_new (void *, struct object *);\n");
+      fprintf (stream, "extern void *__deregister_frame_new (void *);\n");
 
       fprintf (stream, "static void reg_frame () {\n");
       fprintf (stream, "\tstatic struct object ob;\n");
-      fprintf (stream, "\t__register_frame_table (frame_table, &ob);\n");
+      fprintf (stream, "\t__register_frame_table_new (frame_table, &ob);\n");
       fprintf (stream, "\t}\n");
 
       fprintf (stream, "static void dereg_frame () {\n");
-      fprintf (stream, "\t__deregister_frame (frame_table);\n");
+      fprintf (stream, "\t__deregister_frame_new (frame_table);\n");
       fprintf (stream, "\t}\n");
     }
 
@@ -1866,15 +1866,16 @@
       write_list (stream, "\t\t&", frame_tables.first);
       fprintf (stream, "\t0\n};\n");
 
-      fprintf (stream, "extern void __register_frame_table (void *);\n");
-      fprintf (stream, "extern void __deregister_frame (void *);\n");
+      fprintf (stream, "extern void __register_frame_table_new (void *, struct object *);\n");
+      fprintf (stream, "extern void *__deregister_frame_new (void *);\n");
 
       fprintf (stream, "static void reg_frame () {\n");
-      fprintf (stream, "\t__register_frame_table (frame_table);\n");
+      fprintf (stream, "\tstatic struct object ob;\n");
+      fprintf (stream, "\t__register_frame_table_new (frame_table, &ob);\n");
       fprintf (stream, "\t}\n");
 
       fprintf (stream, "static void dereg_frame () {\n");
-      fprintf (stream, "\t__deregister_frame (frame_table);\n");
+      fprintf (stream, "\t__deregister_frame_new (frame_table);\n");
       fprintf (stream, "\t}\n");
     }