[rfa] Fix ppc32 GNU/Linux (and AIX) struct convention

[Andrew Cagney <ac131313 at redhat dot com>]

Hello,

The attached patch fixes the 32 bit PPC GNU/Linux (and AIX) struct 
return code.  PowerOpen returns all structures via a pointer, not just 
the odd sized ones (which is what the generic struct return method tests 
for).

32 bit PPC GNU/Linux, for historic reasons, continues to use this 
convention.  Tested on 32 bit GNU/Linux where structs.exp and 
callfuncs.exp stopped failing.

Note that for GNU/Linux I've made this 32 bit specific.  PPC64 is going 
to need a new method.

ok?
Andrew

2003-09-13  Andrew Cagney  <cagney@redhat.com>

	* ppc-linux-tdep.c (ppc_linux_init_abi): Set the 32 bit
	"use_struct_convention" to "rs6000_use_struct_convention".
	* ppc-tdep.h (rs6000_use_struct_convention): Declare.
	* rs6000-tdep.c (rs6000_use_struct_convention): New function.
	(rs6000_gdbarch_init): For AIX, set "use_struct_convention" to
	"rs6000_use_struct_convention".
	* ppc-sysv-tdep.c (ppc_sysv_abi_broken_use_struct_convention):
	Delete function.
	* ppc-tdep.h (ppc_sysv_abi_broken_use_struct_convention): Delete.

Index: ppc-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/ppc-linux-tdep.c,v
retrieving revision 1.39
diff -u -r1.39 ppc-linux-tdep.c
--- ppc-linux-tdep.c	9 Sep 2003 03:14:02 -0000	1.39
+++ ppc-linux-tdep.c	13 Sep 2003 21:34:36 -0000
@@ -1017,15 +1017,17 @@
 {
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 
-  /* Until November 2001, gcc was not complying to the SYSV ABI for
-     returning structures less than or equal to 8 bytes in size. It was
-     returning everything in memory. When this was corrected, it wasn't
-     fixed for native platforms.  */
-  set_gdbarch_use_struct_convention (gdbarch,
-                                   ppc_sysv_abi_broken_use_struct_convention);
-
   if (tdep->wordsize == 4)
     {
+      /* Until November 2001, gcc did not comply with the SysV R4 ABI
+	 requirement that structures less than or equal to 8 bytes
+	 should be returned in registers.  Instead GCC was using the
+	 the AIX/PowerOpen ABI - everything returned in memory (well
+	 ignoring vectors that is).  When this was corrected, it
+	 wasn't fixed for GNU/Linux native platform.  Use the
+	 PowerOpen struct convention.  */
+      set_gdbarch_use_struct_convention (gdbarch, rs6000_use_struct_convention);
+
       /* Note: kevinb/2002-04-12: See note in rs6000_gdbarch_init regarding
 	 *_push_arguments().  The same remarks hold for the methods below.  */
       set_gdbarch_frameless_function_invocation (gdbarch,
Index: ppc-sysv-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/ppc-sysv-tdep.c,v
retrieving revision 1.10
diff -u -r1.10 ppc-sysv-tdep.c
--- ppc-sysv-tdep.c	12 Sep 2003 18:55:24 -0000	1.10
+++ ppc-sysv-tdep.c	13 Sep 2003 21:34:39 -0000
@@ -329,20 +329,6 @@
   return sp;
 }
 
-/* Until November 2001, gcc was not complying to the SYSV ABI for 
-   returning structures less than or equal to 8 bytes in size.  It was
-   returning everything in memory.  When this was corrected, it wasn't
-   fixed for native platforms.  */
-int     
-ppc_sysv_abi_broken_use_struct_convention (int gcc_p, struct type *value_type)
-{  
-  if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8)
-      && TYPE_VECTOR (value_type))
-    return 0;                            
-
-  return generic_use_struct_convention (gcc_p, value_type);
-}
-
 /* Structures 8 bytes or less long are returned in the r3 & r4
    registers, according to the SYSV ABI. */
 int
Index: ppc-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/ppc-tdep.h,v
retrieving revision 1.17
diff -u -r1.17 ppc-tdep.h
--- ppc-tdep.h	9 Sep 2003 18:29:27 -0000	1.17
+++ ppc-tdep.h	13 Sep 2003 21:34:40 -0000
@@ -54,6 +54,7 @@
 void rs6000_frame_init_saved_regs (struct frame_info *);
 CORE_ADDR rs6000_frame_chain (struct frame_info *);
 int altivec_register_p (int regno);
+extern int rs6000_use_struct_convention (int, struct type *);
 
 
 /* Return non-zero when the architecture has an FPU (or at least when
Index: rs6000-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/rs6000-tdep.c,v
retrieving revision 1.157
diff -u -r1.157 rs6000-tdep.c
--- rs6000-tdep.c	12 Sep 2003 18:40:18 -0000	1.157
+++ rs6000-tdep.c	13 Sep 2003 21:35:09 -0000
@@ -1372,6 +1372,18 @@
     }
 }
 
+/* PowerOpen always puts structures in memory.  Vectors, which were
+   added later, do get returned in a register though.  */
+
+int     
+rs6000_use_struct_convention (int gcc_p, struct type *value_type)
+{  
+  if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8)
+      && TYPE_VECTOR (value_type))
+    return 0;                            
+  return 1;
+}
+
 static void
 rs6000_extract_return_value (struct type *valtype, char *regbuf, char *valbuf)
 {
@@ -2957,7 +2969,7 @@
     				       ppc_sysv_abi_use_struct_convention);
   else
     set_gdbarch_use_struct_convention (gdbarch,
-				       generic_use_struct_convention);
+				       rs6000_use_struct_convention);
 
   set_gdbarch_frameless_function_invocation (gdbarch,
                                          rs6000_frameless_function_invocation);