Re: [PATCH/RFA] Generic OS ABI handling

[Jason R Thorpe <thorpej@wasabisystems.com>]

[-- Attachment #1: Type: text/plain, Size: 941 bytes --]

On Mon, May 13, 2002 at 12:08:40PM -0700, Jason R Thorpe wrote:

 > Ok, I think it's reached the point where I'd like to ask for formal
 > approval.

FYI...

I went ahead and converted the ARM target, as well, as it provides
an example of an OS ABI sniffer.

	* arm-linux-tdep.c (_initialize_arm_linux_tdep): Use
	gdbarch_register_osabi.
	* arm-tdep.c (arm_abi_names, process_note_abi_tag_sections,
	get_elfosabi, arm_abi_handler_list, arm_gdbarch_register_os_abi):
	Remove.
	(arm_gdbarch_init): Use the generic OS ABI framework.
	(arm_dump_tdep): Likewise.
	(_initialize_arm_tdep): Likewise.
	* arm-tdep.h (arm_abi): Remove.
	(gdbarch_tdep): Remove arm_abi and abi_name members.  Add
	osabi member.
	(arm_gdbarch_register_os_abi): Remove prototype.
	* armnbsd-tdep.c (arm_netbsd_aout_osabi_sniffer): New function.
	(_initialize_arm_netbsd_tdep): Use the generic OS ABI framework.

-- 
        -- Jason R. Thorpe <thorpej@wasabisystems.com>

[-- Attachment #2: arm-osabi-patch --]
[-- Type: text/plain, Size: 14427 bytes --]

Index: arm-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/arm-linux-tdep.c,v
retrieving revision 1.20
diff -u -r1.20 arm-linux-tdep.c
--- arm-linux-tdep.c	23 Feb 2002 22:17:11 -0000	1.20
+++ arm-linux-tdep.c	16 May 2002 16:54:15 -0000
@@ -543,5 +543,5 @@
 void
 _initialize_arm_linux_tdep (void)
 {
-  arm_gdbarch_register_os_abi (ARM_ABI_LINUX, arm_linux_init_abi);
+  gdbarch_register_osabi (bfd_arch_arm, GDB_OSABI_LINUX, arm_linux_init_abi);
 }
Index: arm-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/arm-tdep.c,v
retrieving revision 1.60
diff -u -r1.60 arm-tdep.c
--- arm-tdep.c	9 May 2002 18:07:00 -0000	1.60
+++ arm-tdep.c	16 May 2002 16:54:18 -0000
@@ -93,23 +93,6 @@
 #define MSYMBOL_SIZE(msym)				\
 	((long) MSYMBOL_INFO (msym) & 0x7fffffff)
 
-/* This table matches the indicees assigned to enum arm_abi. 
-   Keep them in sync.  */
-
-static const char * const arm_abi_names[] =
-{
-  "<unknown>",
-  "ARM EABI (version 1)",
-  "ARM EABI (version 2)",
-  "GNU/Linux",
-  "NetBSD (a.out)",
-  "NetBSD (ELF)",
-  "APCS",
-  "FreeBSD",
-  "Windows CE",
-  NULL
-};
-
 /* Number of different reg name sets (options).  */
 static int num_flavor_options;
 
@@ -2608,208 +2591,6 @@
 }
 
 \f
-static void
-process_note_abi_tag_sections (bfd *abfd, asection *sect, void *obj)
-{
-  enum arm_abi *os_ident_ptr = obj;
-  const char *name;
-  unsigned int sectsize;
-
-  name = bfd_get_section_name (abfd, sect);
-  sectsize = bfd_section_size (abfd, sect);
-
-  if (strcmp (name, ".note.ABI-tag") == 0 && sectsize > 0)
-    {
-      unsigned int name_length, data_length, note_type;
-      char *note;
-
-      /* If the section is larger than this, it's probably not what we are
-	 looking for.  */
-      if (sectsize > 128)
-	sectsize = 128;
-
-      note = alloca (sectsize);
-
-      bfd_get_section_contents (abfd, sect, note,
-                                (file_ptr) 0, (bfd_size_type) sectsize);
-
-      name_length = bfd_h_get_32 (abfd, note);
-      data_length = bfd_h_get_32 (abfd, note + 4);
-      note_type   = bfd_h_get_32 (abfd, note + 8);
-
-      if (name_length == 4 && data_length == 16 && note_type == 1
-          && strcmp (note + 12, "GNU") == 0)
-	{
-	  int os_number = bfd_h_get_32 (abfd, note + 16);
-
-	  /* The case numbers are from abi-tags in glibc.  */
-	  switch (os_number)
-	    {
-	    case 0 :
-	      *os_ident_ptr = ARM_ABI_LINUX;
-	      break;
-
-	    case 1 :
-	      internal_error
-		(__FILE__, __LINE__,
-		 "process_note_abi_sections: Hurd objects not supported");
-	      break;
-
-	    case 2 :
-	      internal_error
-		(__FILE__, __LINE__,
-		 "process_note_abi_sections: Solaris objects not supported");
-	      break;
-
-	    default :
-	      internal_error
-		(__FILE__, __LINE__,
-		 "process_note_abi_sections: unknown OS number %d",
-		 os_number);
-	      break;
-	    }
-	}
-    }
-  /* NetBSD uses a similar trick.  */
-  else if (strcmp (name, ".note.netbsd.ident") == 0 && sectsize > 0)
-    {
-      unsigned int name_length, desc_length, note_type;
-      char *note;
-
-      /* If the section is larger than this, it's probably not what we are
-	 looking for.  */
-      if (sectsize > 128)
-	sectsize = 128;
-
-      note = alloca (sectsize);
-
-      bfd_get_section_contents (abfd, sect, note,
-                                (file_ptr) 0, (bfd_size_type) sectsize);
-
-      name_length = bfd_h_get_32 (abfd, note);
-      desc_length = bfd_h_get_32 (abfd, note + 4);
-      note_type   = bfd_h_get_32 (abfd, note + 8);
-
-      if (name_length == 7 && desc_length == 4 && note_type == 1
-          && strcmp (note + 12, "NetBSD") == 0)
-	/* XXX Should we check the version here?
-	   Probably not necessary yet.  */
-	*os_ident_ptr = ARM_ABI_NETBSD_ELF;
-    }
-}
-
-/* Return one of the ELFOSABI_ constants for BFDs representing ELF
-   executables.  If it's not an ELF executable or if the OS/ABI couldn't
-   be determined, simply return -1.  */
-
-static int
-get_elfosabi (bfd *abfd)
-{
-  int elfosabi;
-  enum arm_abi arm_abi = ARM_ABI_UNKNOWN;
-
-  elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI];
-
-  /* When elfosabi is 0 (ELFOSABI_NONE), this is supposed to indicate
-     that we're on a SYSV system.  However, GNU/Linux uses a note section
-     to record OS/ABI info, but leaves e_ident[EI_OSABI] zero.  So we
-     have to check the note sections too.
-
-     GNU/ARM tools set the EI_OSABI field to ELFOSABI_ARM, so handle that
-     as well.  */
-  if (elfosabi == 0 || elfosabi == ELFOSABI_ARM)
-    {
-      bfd_map_over_sections (abfd,
-			     process_note_abi_tag_sections,
-			     &arm_abi);
-    }
-
-  if (arm_abi != ARM_ABI_UNKNOWN)
-    return arm_abi;
-
-  switch (elfosabi)
-    {
-    case ELFOSABI_NONE:
-      /* Existing ARM Tools don't set this field, so look at the EI_FLAGS
-	 field for more information.  */
-
-      switch (EF_ARM_EABI_VERSION(elf_elfheader(abfd)->e_flags))
-	{
-	case EF_ARM_EABI_VER1:
-	  return ARM_ABI_EABI_V1;
-
-	case EF_ARM_EABI_VER2:
-	  return ARM_ABI_EABI_V2;
-
-	case EF_ARM_EABI_UNKNOWN:
-	  /* Assume GNU tools.  */
-	  return ARM_ABI_APCS;
-
-	default:
-	  internal_error (__FILE__, __LINE__,
-			  "get_elfosabi: Unknown ARM EABI version 0x%lx",
-			  EF_ARM_EABI_VERSION(elf_elfheader(abfd)->e_flags));
-
-	}
-      break;
-
-    case ELFOSABI_NETBSD:
-      return ARM_ABI_NETBSD_ELF;
-
-    case ELFOSABI_FREEBSD:
-      return ARM_ABI_FREEBSD;
-
-    case ELFOSABI_LINUX:
-      return ARM_ABI_LINUX;
-
-    case ELFOSABI_ARM:
-      /* Assume GNU tools with the old APCS abi.  */
-      return ARM_ABI_APCS;
-
-    default:
-    }
-
-  return ARM_ABI_UNKNOWN;
-}
-
-struct arm_abi_handler
-{
-  struct arm_abi_handler *next;
-  enum arm_abi abi;
-  void (*init_abi)(struct gdbarch_info, struct gdbarch *);
-};
-
-struct arm_abi_handler *arm_abi_handler_list = NULL;
-
-void
-arm_gdbarch_register_os_abi (enum arm_abi abi,
-			     void (*init_abi)(struct gdbarch_info,
-					      struct gdbarch *))
-{
-  struct arm_abi_handler **handler_p;
-
-  for (handler_p = &arm_abi_handler_list; *handler_p != NULL;
-       handler_p = &(*handler_p)->next)
-    {
-      if ((*handler_p)->abi == abi)
-	{
-	  internal_error
-	    (__FILE__, __LINE__,
-	     "arm_gdbarch_register_os_abi: A handler for this ABI variant (%d)"
-	     " has already been registered", (int)abi);
-	  /* If user wants to continue, override previous definition.  */
-	  (*handler_p)->init_abi = init_abi;
-	  return;
-	}
-    }
-
-  (*handler_p)
-    = (struct arm_abi_handler *) xmalloc (sizeof (struct arm_abi_handler));
-  (*handler_p)->next = NULL;
-  (*handler_p)->abi = abi;
-  (*handler_p)->init_abi = init_abi;
-}
-
 /* Initialize the current architecture based on INFO.  If possible,
    re-use an architecture from ARCHES, which is a list of
    architectures already created during this debugging session.
@@ -2822,36 +2603,31 @@
 {
   struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
-  enum arm_abi arm_abi = ARM_ABI_UNKNOWN;
-  struct arm_abi_handler *abi_handler;
+  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
 
   /* Try to deterimine the ABI of the object we are loading.  */
 
   if (info.abfd != NULL)
     {
-      switch (bfd_get_flavour (info.abfd))
+      osabi = gdbarch_lookup_osabi (info.abfd);
+      if (osabi == GDB_OSABI_UNKNOWN)
 	{
-	case bfd_target_elf_flavour:
-	  arm_abi = get_elfosabi (info.abfd);
-	  break;
-
-	case bfd_target_aout_flavour:
-	  if (strcmp (bfd_get_target(info.abfd), "a.out-arm-netbsd") == 0)
-	    arm_abi = ARM_ABI_NETBSD_AOUT;
-	  else
-	    /* Assume it's an old APCS-style ABI.  */
-	    arm_abi = ARM_ABI_APCS;
-	  break;
+	  switch (bfd_get_flavour (info.abfd))
+	    {
+	    case bfd_target_aout_flavour:
+	      /* Assume it's an old APCS-style ABI.  */
+	      osabi = GDB_OSABI_ARM_APCS;
+	      break;
 
-	case bfd_target_coff_flavour:
-	  /* Assume it's an old APCS-style ABI.  */
-	  /* XXX WinCE?  */
-	  arm_abi = ARM_ABI_APCS;
-	  break;
+	    case bfd_target_coff_flavour:
+	      /* Assume it's an old APCS-style ABI.  */
+	      /* XXX WinCE?  */
+	      osabi = GDB_OSABI_ARM_APCS;
+	      break;
 
-	default:
-	  /* Not sure what to do here, leave the ABI as unknown.  */
-	  break;
+	    default:
+	      /* Leave it as "unknown".  */
+	    }
 	}
     }
 
@@ -2862,22 +2638,14 @@
     {
       /* Make sure the ABI selection matches.  */
       tdep = gdbarch_tdep (arches->gdbarch);
-      if (tdep && tdep->arm_abi == arm_abi)
+      if (tdep && tdep->osabi == osabi)
 	return arches->gdbarch;
     }
 
   tdep = xmalloc (sizeof (struct gdbarch_tdep));
   gdbarch = gdbarch_alloc (&info, tdep);
 
-  tdep->arm_abi = arm_abi;
-  if (arm_abi < ARM_ABI_INVALID)
-    tdep->abi_name = arm_abi_names[arm_abi];
-  else
-    {
-      internal_error (__FILE__, __LINE__, "Invalid setting of arm_abi %d",
-		      (int) arm_abi);
-      tdep->abi_name = "<invalid>";
-    }
+  tdep->osabi = osabi;
 
   /* This is the way it has always defaulted.  */
   tdep->fp_model = ARM_FLOAT_FPA;
@@ -3047,38 +2815,7 @@
 					 arm_coff_make_msymbol_special);
 
   /* Hook in the ABI-specific overrides, if they have been registered.  */
-  if (arm_abi == ARM_ABI_UNKNOWN)
-    {
-      /* Don't complain about not knowing the ABI variant if we don't 
-	 have an inferior.  */
-      if (info.abfd)
-	fprintf_filtered
-	  (gdb_stderr, "GDB doesn't recognize the ABI of the inferior.  "
-	   "Attempting to continue with the default ARM settings");
-    }
-  else
-    {
-      for (abi_handler = arm_abi_handler_list; abi_handler != NULL;
-	   abi_handler = abi_handler->next)
-	if (abi_handler->abi == arm_abi)
-	  break;
-
-      if (abi_handler)
-	abi_handler->init_abi (info, gdbarch);
-      else
-	{
-	  /* We assume that if GDB_MULTI_ARCH is less than 
-	     GDB_MULTI_ARCH_TM that an ABI variant can be supported by
-	     overriding definitions in this file.  */
-	  if (GDB_MULTI_ARCH > GDB_MULTI_ARCH_PARTIAL)
-	    fprintf_filtered
-	      (gdb_stderr,
-	       "A handler for the ABI variant \"%s\" is not built into this "
-	       "configuration of GDB.  "
-	       "Attempting to continue with the default ARM settings",
-	       arm_abi_names[arm_abi]);
-	}
-    }
+  gdbarch_init_osabi (info, gdbarch, osabi);
 
   /* Now we have tuned the configuration, set a few final things,
      based on what the OS ABI has told us.  */
@@ -3144,12 +2881,8 @@
   if (tdep == NULL)
     return;
 
-  if (tdep->abi_name != NULL)
-    fprintf_unfiltered (file, "arm_dump_tdep: ABI = %s\n", tdep->abi_name);
-  else
-    internal_error (__FILE__, __LINE__,
-		    "arm_dump_tdep: illegal setting of tdep->arm_abi (%d)",
-		    (int) tdep->arm_abi);
+  fprintf_unfiltered (file, "arm_dump_tdep: OS ABI = %s\n",
+		      gdbarch_osabi_name (tdep->osabi));
 
   fprintf_unfiltered (file, "arm_dump_tdep: Lowest pc = 0x%lx",
 		      (unsigned long) tdep->lowest_pc);
@@ -3192,9 +2925,12 @@
     gdbarch_register (bfd_arch_arm, arm_gdbarch_init, arm_dump_tdep);
 
   /* Register some ABI variants for embedded systems.  */
-  arm_gdbarch_register_os_abi (ARM_ABI_EABI_V1, arm_init_abi_eabi_v1);
-  arm_gdbarch_register_os_abi (ARM_ABI_EABI_V2, arm_init_abi_eabi_v2);
-  arm_gdbarch_register_os_abi (ARM_ABI_APCS, arm_init_abi_apcs);
+  gdbarch_register_osabi (bfd_arch_arm, GDB_OSABI_ARM_EABI_V1,
+                          arm_init_abi_eabi_v1);
+  gdbarch_register_osabi (bfd_arch_arm, GDB_OSABI_ARM_EABI_V2,
+                          arm_init_abi_eabi_v2);
+  gdbarch_register_osabi (bfd_arch_arm, GDB_OSABI_ARM_APCS,
+                          arm_init_abi_apcs);
 
   tm_print_insn = gdb_print_insn_arm;
 
Index: arm-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/arm-tdep.h,v
retrieving revision 1.8
diff -u -r1.8 arm-tdep.h
--- arm-tdep.h	7 May 2002 12:58:51 -0000	1.8
+++ arm-tdep.h	16 May 2002 16:54:19 -0000
@@ -104,23 +104,6 @@
 #define FLAG_C		0x20000000
 #define FLAG_V		0x10000000
 
-/* ABI variants that we know about.  If you add to this enum, please 
-   update the table of names in tm-arm.c.  */
-enum arm_abi
-{
-  ARM_ABI_UNKNOWN = 0,
-  ARM_ABI_EABI_V1,
-  ARM_ABI_EABI_V2,
-  ARM_ABI_LINUX,
-  ARM_ABI_NETBSD_AOUT,
-  ARM_ABI_NETBSD_ELF,
-  ARM_ABI_APCS,
-  ARM_ABI_FREEBSD,
-  ARM_ABI_WINCE,
-
-  ARM_ABI_INVALID	/* Keep this last.  */
-};
-
 /* Type of floating-point code in use by inferior.  There are really 3 models
    that are traditionally supported (plus the endianness issue), but gcc can
    only generate 2 of those.  The third is APCS_FLOAT, where arguments to
@@ -139,8 +122,7 @@
 /* Target-dependent structure in gdbarch.  */
 struct gdbarch_tdep
 {
-  enum arm_abi arm_abi;		/* OS/ABI of inferior.  */
-  const char *abi_name;		/* Name of the above.  */
+  enum gdb_osabi osabi;		/* OS/ABI of inferior.  */
 
   enum arm_float_model fp_model; /* Floating point calling conventions.  */
 
@@ -170,10 +152,3 @@
 CORE_ADDR thumb_get_next_pc (CORE_ADDR);
 
 CORE_ADDR arm_get_next_pc (CORE_ADDR);
-
-/* How a OS variant tells the ARM generic code that it can handle an ABI
-   type. */
-void
-arm_gdbarch_register_os_abi (enum arm_abi abi,
-			     void (*init_abi)(struct gdbarch_info,
-					      struct gdbarch *));
Index: armnbsd-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/armnbsd-tdep.c,v
retrieving revision 1.4
diff -u -r1.4 armnbsd-tdep.c
--- armnbsd-tdep.c	19 Feb 2002 19:20:31 -0000	1.4
+++ armnbsd-tdep.c	16 May 2002 16:54:19 -0000
@@ -77,9 +77,23 @@
   tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 }
 
+static enum gdb_osabi
+arm_netbsd_aout_osabi_sniffer (bfd *abfd)
+{
+  if (strcmp (bfd_get_target (abfd), "a.out-arm-netbsd") == 0)
+    return GDB_OSABI_NETBSD_AOUT;
+
+  return GDB_OSABI_UNKNOWN;
+}
+
 void
 _initialize_arm_netbsd_tdep (void)
 {
-  arm_gdbarch_register_os_abi (ARM_ABI_NETBSD_AOUT, arm_netbsd_aout_init_abi);
-  arm_gdbarch_register_os_abi (ARM_ABI_NETBSD_ELF, arm_netbsd_elf_init_abi);
+  gdbarch_register_osabi_sniffer (bfd_arch_arm, bfd_target_aout_flavour,
+				  arm_netbsd_aout_osabi_sniffer);
+
+  gdbarch_register_osabi (bfd_arch_arm, GDB_OSABI_NETBSD_AOUT,
+                          arm_netbsd_aout_init_abi);
+  gdbarch_register_osabi (bfd_arch_arm, GDB_OSABI_NETBSD_ELF,
+                          arm_netbsd_elf_init_abi);
 }