[PATCH RFC] arm-tdep.c: Define SVR4 link map offset fetcher

[Kevin Buettner <kevinb@redhat.com>]

The patch below adds shared library support for non-native ARM linux
targets.  I'll wait a few days for comments before committing it.

Kevin

	From Louis Hamilton  <hamilton@redhat.com>:
	* arm-tdep.c (solib-svr4.h): Include.
	(arm_linux_svr4_fetch_link_map_offsets): New function.
	* config/arm/tm-linux.h (SVR4_FETCH_LINK_MAP_OFFSETS): Define.
	(arm_linux_svr4_fetch_link_map_offsets): Declare.

Index: arm-tdep.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/arm-tdep.c,v
retrieving revision 1.65.8.1.2.1
diff -u -p -r1.65.8.1.2.1 arm-tdep.c
--- arm-tdep.c	2001/10/02 15:53:35	1.65.8.1.2.1
+++ arm-tdep.c	2001/11/27 18:42:10
@@ -31,6 +31,7 @@
 #include <ctype.h>		/* for isupper () */
 #include "regcache.h"
 #include "doublest.h"
+#include "solib-svr4.h"
 
 /* Each OS has a different mechanism for accessing the various
    registers stored in the sigcontext structure.
@@ -2094,6 +2101,49 @@ arm_othernames (char *names, int n)
 
   disassembly_flavor = valid_flavors[current_option];
   set_disassembly_flavor (); 
+}
+
+/* Fetch, and possibly build, an appropriate link_map_offsets structure
+   for ARM linux targets using the struct offsets defined in <link.h>.
+   Note, however, that link.h is not actually referred to in this file.
+   Instead, the relevant structs offsets were obtained from examining
+   link.h.  (We can't refer to link.h from this file because the host
+   system won't necessarily have it, or if it does, the structs which
+   it defines will refer to the host system, not the target.  */
+
+struct link_map_offsets *
+arm_linux_svr4_fetch_link_map_offsets (void)
+{
+  static struct link_map_offsets lmo;
+  static struct link_map_offsets *lmp = 0;
+
+  if (lmp == 0)
+    {
+      lmp = &lmo;
+
+      lmo.r_debug_size = 8;	/* Actual size is 20, but this is all we
+                                   need. */
+
+      lmo.r_map_offset = 4;
+      lmo.r_map_size   = 4;
+
+      lmo.link_map_size = 20;	/* Actual size is 552, but this is all we
+                                   need. */
+
+      lmo.l_addr_offset = 0;
+      lmo.l_addr_size   = 4;
+
+      lmo.l_name_offset = 4;
+      lmo.l_name_size   = 4;
+
+      lmo.l_next_offset = 12;
+      lmo.l_next_size   = 4;
+
+      lmo.l_prev_offset = 16;
+      lmo.l_prev_size   = 4;
+    }
+
+    return lmp;
 }
 
 void
Index: config/arm/tm-linux.h
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/config/arm/tm-linux.h,v
retrieving revision 1.5
diff -u -p -r1.5 tm-linux.h
--- config/arm/tm-linux.h	2000/09/07 12:34:17	1.5
+++ config/arm/tm-linux.h	2001/11/27 18:42:11
@@ -26,6 +26,10 @@
 
 #include "tm-linux.h"
 
+/* Use target-specific function to define link map offsets.  */
+extern struct link_map_offsets *arm_linux_svr4_fetch_link_map_offsets (void);
+#define SVR4_FETCH_LINK_MAP_OFFSETS() arm_linux_svr4_fetch_link_map_offsets ()
+
 /* Target byte order on ARM Linux is little endian and not selectable.  */
 #undef TARGET_BYTE_ORDER_SELECTABLE_P
 #define TARGET_BYTE_ORDER_SELECTABLE_P	0