Re: [patch] use .gnu.attributes to detect e500 machine type

[Aleksandar Ristovski <aristovski@qnx.com>]

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ping?

Note: new patch attached taking into account current_gdbarch 
removal.



Aleksandar Ristovski wrote:
> Joel, thank you for reviewing this.
> 
> 
> Joel Brobecker wrote:
>>> * rs6000-tdep.c (rs6000_gdbarch_init): Use .gnu.attributes to see
>>> if this is a e500 binary (with SPE APU).
>>> (powerpc_show_vector_abi): New function.
>>
>> If you look at today's version of rs6000_gdbarch_init, you'll find
>> that we're already checking the Tag_GNU_Power_ABI_Vector, and setting
>> the tdep->vector_abi accordingly. It's actually conditionalized on
>> HAVE_ELF, so we need at least to make sure that your testing of
>> the .gnu.attributes sections gets conditionalized on HAVE_ELF as well.
>>
>> However, I am wondering if it wouldn't be better to simply take
>> advantage of the code that's already there. For that, you'll need
>> to move the code up a bit, so that vector_abi gets set earlier.
>> You can then use the resulting information to determine whether or
>> not to fallback on the current approach of using .PPC.EMB.apuinfo.
> 
> With rearanged code, the patch is simpler, but functionally the same.
> 
> My original patch is broken into two, the one dealing with 
> rs6000_gdbarch_init changes and using .gnu.attributes, and the other 
> with printing "powerpc vector-abi" information.
> 
> 
> Change logs:
>     * rs6000-tdep.c (rs6000_gdbarch_init): Rearange the code to use
>     .gnu.attributes to see if this is a e500 binary (with SPE APU).
> 
> 
> 
>     * rs6000-tdep.c (powerpc_show_vector_abi): New function.
>     (_initialize_rs6000_tdep): Use powerpc_show_vector_abi.
> 
> 
> 
> 
> Thank you,
> 
> Aleksandar
> 


-- 
Aleksandar Ristovski
QNX Software Systems




ChangeLog for rs6000-tdep-mach_type_from_gnu_obj_attr:

* rs6000-tdep.c (rs6000_gdbarch_init): Rearange the code to use
.gnu.attributes to see if this is a e500 binary (with SPE APU).


ChangeLog for rs6000-tdep-show_vector_abi:

* rs6000-tdep.c (powerpc_show_vector_abi): New function.
(_initialize_rs6000_tdep): Use powerpc_show_vector_abi.




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Index: gdb/rs6000-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/rs6000-tdep.c,v
retrieving revision 1.334
diff -u -p -r1.334 rs6000-tdep.c
--- gdb/rs6000-tdep.c	2 Jul 2009 17:25:58 -0000	1.334
+++ gdb/rs6000-tdep.c	6 Jul 2009 16:24:41 -0000
@@ -3390,6 +3390,43 @@ rs6000_gdbarch_init (struct gdbarch_info
 	wordsize = 4;
     }
 
+#ifdef HAVE_ELF
+  if (soft_float_flag == AUTO_BOOLEAN_AUTO && from_elf_exec)
+    {
+      switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_GNU,
+					Tag_GNU_Power_ABI_FP))
+	{
+	case 1:
+	  soft_float_flag = AUTO_BOOLEAN_FALSE;
+	  break;
+	case 2:
+	  soft_float_flag = AUTO_BOOLEAN_TRUE;
+	  break;
+	default:
+	  break;
+	}
+    }
+
+  if (vector_abi == POWERPC_VEC_AUTO && from_elf_exec)
+    {
+      switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_GNU,
+					Tag_GNU_Power_ABI_Vector))
+	{
+	case 1:
+	  vector_abi = POWERPC_VEC_GENERIC;
+	  break;
+	case 2:
+	  vector_abi = POWERPC_VEC_ALTIVEC;
+	  break;
+	case 3:
+	  vector_abi = POWERPC_VEC_SPE;
+	  break;
+	default:
+	  break;
+	}
+    }
+#endif
+
   /* Get the architecture and machine from the BFD.  */
   arch = info.bfd_arch_info->arch;
   mach = info.bfd_arch_info->mach;
@@ -3402,16 +3439,14 @@ rs6000_gdbarch_init (struct gdbarch_info
      which version of it) can execute it. In our case we just look for
      the existance of the section.  */
 
-  if (info.abfd)
-    {
-      sect = bfd_get_section_by_name (info.abfd, ".PPC.EMB.apuinfo");
-      if (sect)
-	{
-	  arch = info.bfd_arch_info->arch;
-	  mach = bfd_mach_ppc_e500;
-	  bfd_default_set_arch_mach (&abfd, arch, mach);
-	  info.bfd_arch_info = bfd_get_arch_info (&abfd);
-	}
+  if (vector_abi == POWERPC_VEC_SPE
+      || (info.abfd
+	  && bfd_get_section_by_name (info.abfd, ".PPC.EMB.apuinfo") != NULL))
+    {
+      mach = bfd_mach_ppc_e500;
+      arch = info.bfd_arch_info->arch;
+      bfd_default_set_arch_mach (&abfd, arch, mach);
+      info.bfd_arch_info = bfd_get_arch_info (&abfd);
     }
 
   /* Find a default target description which describes our register
@@ -3648,43 +3683,6 @@ rs6000_gdbarch_init (struct gdbarch_info
       return NULL;
     }
 
-#ifdef HAVE_ELF
-  if (soft_float_flag == AUTO_BOOLEAN_AUTO && from_elf_exec)
-    {
-      switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_GNU,
-					Tag_GNU_Power_ABI_FP))
-	{
-	case 1:
-	  soft_float_flag = AUTO_BOOLEAN_FALSE;
-	  break;
-	case 2:
-	  soft_float_flag = AUTO_BOOLEAN_TRUE;
-	  break;
-	default:
-	  break;
-	}
-    }
-
-  if (vector_abi == POWERPC_VEC_AUTO && from_elf_exec)
-    {
-      switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_GNU,
-					Tag_GNU_Power_ABI_Vector))
-	{
-	case 1:
-	  vector_abi = POWERPC_VEC_GENERIC;
-	  break;
-	case 2:
-	  vector_abi = POWERPC_VEC_ALTIVEC;
-	  break;
-	case 3:
-	  vector_abi = POWERPC_VEC_SPE;
-	  break;
-	default:
-	  break;
-	}
-    }
-#endif
-
   if (soft_float_flag == AUTO_BOOLEAN_TRUE)
     soft_float = 1;
   else if (soft_float_flag == AUTO_BOOLEAN_FALSE)

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Index: gdb/rs6000-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/rs6000-tdep.c,v
retrieving revision 1.334
diff -u -p -r1.334 rs6000-tdep.c
--- gdb/rs6000-tdep.c	2 Jul 2009 17:25:58 -0000	1.334
+++ gdb/rs6000-tdep.c	6 Jul 2009 16:24:41 -0000
@@ -4022,6 +4020,36 @@ powerpc_set_vector_abi (char *args, int 
     internal_error (__FILE__, __LINE__, "could not update architecture");
 }
 
+static void
+powerpc_show_vector_abi (struct ui_file *file,
+			 int from_tty,
+			 struct cmd_list_element *c,
+			 const char *value)
+{
+  struct gdbarch *gdbarch = target_gdbarch;
+  enum powerpc_vector_abi tdep_vector_abi;
+  int global_msg_only = 0;
+
+  if (gdbarch == NULL)
+    global_msg_only = 1;
+  else 
+    {
+      tdep_vector_abi = gdbarch_tdep (gdbarch)->vector_abi;
+      if (strcmp (powerpc_vector_abi_string,
+		  powerpc_vector_strings[tdep_vector_abi]) == 0)
+	global_msg_only = 1;
+    }
+
+  if (global_msg_only)
+    printf_unfiltered ("The vector ABI is \"%s\"\n",
+		       powerpc_vector_abi_string);
+  else
+    printf_unfiltered ("\
+The vector ABI in use is \"%s\". Default setting is \"%s\".\n",
+		       powerpc_vector_strings[tdep_vector_abi],
+		       powerpc_vector_abi_string); 
+}
+
 /* Initialization code.  */
 
 extern initialize_file_ftype _initialize_rs6000_tdep; /* -Wmissing-prototypes */
@@ -4075,6 +4103,6 @@ _initialize_rs6000_tdep (void)
 			&powerpc_vector_abi_string,
 			_("Set the vector ABI."),
 			_("Show the vector ABI."),
-			NULL, powerpc_set_vector_abi, NULL,
+			NULL, powerpc_set_vector_abi, powerpc_show_vector_abi,
 			&setpowerpccmdlist, &showpowerpccmdlist);
 }