[rfc] Simplify ppc64_sysv_abi_adjust_breakpoint_address

["Ulrich Weigand" <uweigand@de.ibm.com>]

Hello,

this is another patch to simplify powerpc64-linux code.  We used to 
handle minimal symbols pointing to function descriptors by installing
a ppc64_sysv_abi_adjust_breakpoint_address routine.  This always had
a number of unpleasant side effects, for example it broke prologue
skipping, and it tended to print out annoying warning messages.

With my recent changes to handle function descriptors directly in
linespec.c:minsym_found, the underlying problem is already handled
(and without those side effects) before we ever get into the last-
ditch adjust_breakpoint_address code, so this no longer has any
effect.

Thus I'd propose to remove that code.  Any objections?

Tested on powerpc64-linux with no change in behaviour.

Thanks,
Ulrich


ChangeLog:

	* ppc-linux-tdep.c (ppc_linux_init_abi): Do not install
	ppc64_sysv_abi_adjust_breakpoint_address.
	* ppc-sysv-tdep.c (ppc64_sysv_abi_adjust_breakpoint_address): Remove.
	* ppc-tdep.h (ppc64_sysv_abi_adjust_breakpoint_address): Remove.


diff -urNp gdb-orig/gdb/ppc-linux-tdep.c gdb-head/gdb/ppc-linux-tdep.c
--- gdb-orig/gdb/ppc-linux-tdep.c	2008-05-14 20:28:48.244451000 +0200
+++ gdb-head/gdb/ppc-linux-tdep.c	2008-05-14 21:13:05.634689598 +0200
@@ -1024,15 +1024,6 @@ ppc_linux_init_abi (struct gdbarch_info 
   
   if (tdep->wordsize == 8)
     {
-       /* Handle the 64-bit SVR4 minimal-symbol convention of using "FN"
-	  for the descriptor and ".FN" for the entry-point -- a user
-	  specifying "break FN" will unexpectedly end up with a breakpoint
-	  on the descriptor and not the function.  This architecture method
-	  transforms any breakpoints on descriptors into breakpoints on the
-	  corresponding entry point.  */
-      set_gdbarch_adjust_breakpoint_address
-	(gdbarch, ppc64_sysv_abi_adjust_breakpoint_address);
-
       /* Handle PPC GNU/Linux 64-bit function pointers (which are really
 	 function descriptors).  */
       set_gdbarch_convert_from_func_ptr_addr
diff -urNp gdb-orig/gdb/ppc-sysv-tdep.c gdb-head/gdb/ppc-sysv-tdep.c
--- gdb-orig/gdb/ppc-sysv-tdep.c	2008-05-11 23:02:59.000000000 +0200
+++ gdb-head/gdb/ppc-sysv-tdep.c	2008-05-14 21:13:18.323862623 +0200
@@ -1510,20 +1510,3 @@ ppc64_sysv_abi_return_value (struct gdba
   return RETURN_VALUE_STRUCT_CONVENTION;
 }
 
-CORE_ADDR
-ppc64_sysv_abi_adjust_breakpoint_address (struct gdbarch *gdbarch,
-					  CORE_ADDR bpaddr)
-{
-  /* PPC64 SYSV specifies that the minimal-symbol "FN" should point at
-     a function-descriptor while the corresponding minimal-symbol
-     ".FN" should point at the entry point.  Consequently, a command
-     like "break FN" applied to an object file with only minimal
-     symbols, will insert the breakpoint into the descriptor at "FN"
-     and not the function at ".FN".  Avoid this confusion by adjusting
-     any attempt to set a descriptor breakpoint into a corresponding
-     function breakpoint.  Note that GDB warns the user when this
-     adjustment is applied - that's ok as otherwise the user will have
-     no way of knowing why their breakpoint at "FN" resulted in the
-     program stopping at ".FN".  */
-  return gdbarch_convert_from_func_ptr_addr (gdbarch, bpaddr, &current_target);
-}
diff -urNp gdb-orig/gdb/ppc-tdep.h gdb-head/gdb/ppc-tdep.h
--- gdb-orig/gdb/ppc-tdep.h	2008-05-11 23:02:59.000000000 +0200
+++ gdb-head/gdb/ppc-tdep.h	2008-05-14 21:13:42.342003078 +0200
@@ -54,9 +54,6 @@ CORE_ADDR ppc64_sysv_abi_push_dummy_call
 					  struct value **args, CORE_ADDR sp,
 					  int struct_return,
 					  CORE_ADDR struct_addr);
-CORE_ADDR ppc64_sysv_abi_adjust_breakpoint_address (struct gdbarch *gdbarch,
-						    CORE_ADDR bpaddr);
-
 enum return_value_convention ppc64_sysv_abi_return_value (struct gdbarch *gdbarch,
 							  struct type *func_type,
 							  struct type *valtype,
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com