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

[Andrew Cagney <ac131313@redhat.com>]

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> On Sep 13,  5:57pm, Andrew Cagney wrote:
> 
> 
>> 	* 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.
> 
> 
> No.  I would prefer that ppc-linux-tdep.c contain its own (suitably
> named) "use_struct_convention" code even if it's identical to the code
> needed by AIX.  That way we can tweak one without having to worry
> about breaking the other.

Done.  This is what I've checked in.

Andrew


> 
>> 	* rs6000-tdep.c (rs6000_use_struct_convention): New function.
>> 	(rs6000_gdbarch_init): For AIX, set "use_struct_convention" to
>> 	"rs6000_use_struct_convention".
> 
> 
> Okay.
> 
> 
>> 	* ppc-sysv-tdep.c (ppc_sysv_abi_broken_use_struct_convention):
>> 	Delete function.
>> 	* ppc-tdep.h (ppc_sysv_abi_broken_use_struct_convention): Delete.
> 
> 
> Okay.
> 
> Kevin
> 


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2003-09-16  Andrew Cagney  <cagney@redhat.com>

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

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	16 Sep 2003 23:28:18 -0000
@@ -591,6 +591,20 @@
   return val;
 }
 
+/* For historic reasons, PPC 32 GNU/Linux follows PowerOpen rather
+   than the 32 bit SYSV R4 ABI structure return convention - all
+   structures, no matter their size, are put in memory.  Vectors,
+   which were added later, do get returned in a register though.  */
+
+static int     
+ppc_linux_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;
+}
+
 /* Fetch (and possibly build) an appropriate link_map_offsets
    structure for GNU/Linux PPC targets using the struct offsets
    defined in link.h (but without actual reference to that file).
@@ -1017,15 +1031,17 @@
 {
   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 32 bit 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, ppc_linux_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	16 Sep 2003 23:28:19 -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: rs6000-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/rs6000-tdep.c,v
retrieving revision 1.159
diff -u -r1.159 rs6000-tdep.c
--- rs6000-tdep.c	14 Sep 2003 22:35:33 -0000	1.159
+++ rs6000-tdep.c	16 Sep 2003 23:28:19 -0000
@@ -1372,6 +1372,18 @@
     }
 }
 
+/* PowerOpen always puts structures in memory.  Vectors, which were
+   added later, do get returned in a register though.  */
+
+static 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);