tm.texi (TARGET_GET_PCH_VALIDITY, [...]): Tweak the documentation to make it more future-proof.

	* doc/tm.texi (TARGET_GET_PCH_VALIDITY, TARGET_PCH_VALID_P): Tweak
	the documentation to make it more future-proof.
	(TARGET_CHECK_PCH_TARGET_FLAGS): Document this new hook.
	* target.h (gcc_target): Add check_pch_target_flags.
	* target-def.h (TARGET_CHECK_PCH_TARGET_FLAGS): New macro.
	(TARGET_INITIALIZER): Include it.
	* toplev.c (default_pch_valid_p): Use targetm.check_pch_target_flags.
	* config/sh/sh.h (sh_pch_valid_p): Delete.
	* config/sh/sh.c (TARGET_PCH_VALID_P, sh_pch_valid_p): Delete.
	(sh_check_pch_target_flags): New function.
	(TARGET_CHECK_PCH_TARGET_FLAGS): Override default.

From-SVN: r100392

gcc/ChangeLog

+2005-05-31  Richard Sandiford  <rsandifo@redhat.com>
+
+	* doc/tm.texi (TARGET_GET_PCH_VALIDITY, TARGET_PCH_VALID_P): Tweak
+	the documentation to make it more future-proof.
+	(TARGET_CHECK_PCH_TARGET_FLAGS): Document this new hook.
+	* target.h (gcc_target): Add check_pch_target_flags.
+	* target-def.h (TARGET_CHECK_PCH_TARGET_FLAGS): New macro.
+	(TARGET_INITIALIZER): Include it.
+	* toplev.c (default_pch_valid_p): Use targetm.check_pch_target_flags.
+	* config/sh/sh.h (sh_pch_valid_p): Delete.
+	* config/sh/sh.c (TARGET_PCH_VALID_P, sh_pch_valid_p): Delete.
+	(sh_check_pch_target_flags): New function.
+	(TARGET_CHECK_PCH_TARGET_FLAGS): Override default.
+
 2005-05-31  Richard Guenther  <rguenth@gcc.gnu.org>
 
 	* fold-const.c (extract_array_ref): Handle more cases,

gcc/config/sh/sh.c

@@ -228,6 +228,7 @@ static tree sh_handle_trap_exit_attribute (tree *, tree, tree, int, bool *);
 static tree sh_handle_renesas_attribute (tree *, tree, tree, int, bool *);
 static void sh_output_function_epilogue (FILE *, HOST_WIDE_INT);
 static void sh_insert_attributes (tree, tree *);
+static const char *sh_check_pch_target_flags (int);
 static int sh_adjust_cost (rtx, rtx, rtx, int);
 static int sh_issue_rate (void);
 static int sh_dfa_new_cycle (FILE *, int, rtx, int, int, int *sort_p);
@@ -467,8 +468,8 @@ static int hard_regs_intersect_p (HARD_REG_SET *, HARD_REG_SET *);
 #undef TARGET_VECTOR_MODE_SUPPORTED_P
 #define TARGET_VECTOR_MODE_SUPPORTED_P sh_vector_mode_supported_p
 
-#undef TARGET_PCH_VALID_P
-#define TARGET_PCH_VALID_P sh_pch_valid_p
+#undef TARGET_CHECK_PCH_TARGET_FLAGS
+#define TARGET_CHECK_PCH_TARGET_FLAGS sh_check_pch_target_flags
 
 #undef TARGET_DWARF_CALLING_CONVENTION
 #define TARGET_DWARF_CALLING_CONVENTION sh_dwarf_calling_convention
@@ -7515,36 +7516,11 @@ sh_cfun_interrupt_handler_p (void)
 	  != NULL_TREE);
 }
 
-/* Like default_pch_valid_p, but only check certain target_flags.  */
-const char *
-sh_pch_valid_p (const void *data_p, size_t len)
-{
-#ifdef TARGET_OPTIONS
-  /* ??? We have a copy of this in toplev.c, but it is static.  */
-  static const struct
-    {
-      const char *const prefix;
-      const char **const variable;
-      const char *const description;
-      const char *const value;
-    }
-  target_options[] = TARGET_OPTIONS;
-#endif
+/* Implement TARGET_CHECK_PCH_TARGET_FLAGS.  */
 
-  const char *data = (const char *)data_p;
-  const char *flag_that_differs = NULL;
-  size_t i;
-  int old_flags;
-
-  /* -fpic and -fpie also usually make a PCH invalid.  */
-  if (data[0] != flag_pic)
-    return _("created and used with different settings of -fpic");
-  if (data[1] != flag_pie)
-    return _("created and used with different settings of -fpie");
-  data += 2;
-
-  /* Check target_flags.  */
-  memcpy (&old_flags, data, sizeof (target_flags));
+static const char *
+sh_check_pch_target_flags (int old_flags)
+{
   if ((old_flags ^ target_flags) & (MASK_SH1 | MASK_SH2 | MASK_SH3
 				    | MASK_SH_E | MASK_HARD_SH4
 				    | MASK_FPU_SINGLE | MASK_SH4))
@@ -7553,40 +7529,7 @@ sh_pch_valid_p (const void *data_p, size_t len)
     return _("created and used with different ABIs");
   if ((old_flags ^ target_flags) & MASK_LITTLE_ENDIAN)
     return _("created and used with different endianness");
-
-  data += sizeof (target_flags);
-  len -= sizeof (target_flags);
-
-  /* Check string options.  */
-#ifdef TARGET_OPTIONS
-  for (i = 0; i < ARRAY_SIZE (target_options); i++)
-    {
-      const char *str = *target_options[i].variable;
-      size_t l;
-      if (! str)
-	str = "";
-      l = strlen (str) + 1;
-      if (len < l || memcmp (data, str, l) != 0)
-	{
-	  flag_that_differs = target_options[i].prefix;
-	  goto make_message;
-	}
-      data += l;
-      len -= l;
-    }
-#endif
-
   return NULL;
-
- make_message:
-  {
-    char *r;
-    asprintf (&r, _("created and used with differing settings of '-m%s'"),
-		  flag_that_differs);
-    if (r == NULL)
-      return _("out of memory");
-    return r;
-  }
 }
 
 /* Predicates used by the templates.  */

gcc/doc/tm.texi

@@ -8668,24 +8668,32 @@ Default: empty.
 @section Parameters for Precompiled Header Validity Checking
 @cindex parameters, precompiled headers
 
-@deftypefn {Target Hook} void * TARGET_GET_PCH_VALIDITY (size_t * @var{sz})
-Define this hook if your target needs to check a different collection
-of flags than the default, which is every flag defined by
-@code{TARGET_SWITCHES} and @code{TARGET_OPTIONS}.  It should return
-some data which will be saved in the PCH file and presented to
-@code{TARGET_PCH_VALID_P} later; it should set @code{SZ} to the size
-of the data.
-@end deftypefn
-
-@deftypefn {Target Hook} const char * TARGET_PCH_VALID_P (const void * @var{data}, size_t @var{sz})
-Define this hook if your target needs to check a different collection of
-flags than the default, which is every flag defined by @code{TARGET_SWITCHES}
-and @code{TARGET_OPTIONS}.  It is given data which came from
-@code{TARGET_GET_PCH_VALIDITY} (in this version of this compiler, so there
-is no need for extensive validity checking).  It returns @code{NULL} if
-it is safe to load a PCH file with this data, or a suitable error message
-if not.  The error message will be presented to the user, so it should
-be localized.
+@deftypefn {Target Hook} void *TARGET_GET_PCH_VALIDITY (size_t *@var{sz})
+This hook returns the data needed by @code{TARGET_PCH_VALID_P} and sets
+@samp{*@var{sz}} to the size of the data in bytes.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_PCH_VALID_P (const void *@var{data}, size_t @var{sz})
+This hook checks whether the options used to create a PCH file are
+compatible with the current settings.  It returns @code{NULL}
+if so and a suitable error message if not.  Error messages will
+be presented to the user and must be localized using @samp{_(@var{msg})}.
+
+@var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}
+when the PCH file was created and @var{sz} is the size of that data in bytes.
+It's safe to assume that the data was created by the same version of the
+compiler, so no format checking is needed.
+
+The default definition of @code{default_pch_valid_p} should be
+suitable for most targets.
+@end deftypefn
+
+@deftypefn {Target Hook} const char *TARGET_CHECK_PCH_TARGET_FLAGS (int @var{pch_flags})
+If this hook is nonnull, the default implementation of
+@code{TARGET_PCH_VALID_P} will use it to check for compatible values
+of @code{target_flags}.  @var{pch_flags} specifies the value that
+@code{target_flags} had when the PCH file was created.  The return
+value is the same as for @code{TARGET_PCH_VALID_P}.
 @end deftypefn
 
 @node C++ ABI

gcc/target-def.h

@@ -379,6 +379,7 @@ Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 #define TARGET_GET_PCH_VALIDITY default_get_pch_validity
 #define TARGET_PCH_VALID_P default_pch_valid_p
+#define TARGET_CHECK_PCH_TARGET_FLAGS NULL
 
 #define TARGET_DEFAULT_SHORT_ENUMS hook_bool_void_false
 
@@ -551,6 +552,7 @@ Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   TARGET_GIMPLIFY_VA_ARG_EXPR,			\
   TARGET_GET_PCH_VALIDITY,			\
   TARGET_PCH_VALID_P,				\
+  TARGET_CHECK_PCH_TARGET_FLAGS,		\
   TARGET_DEFAULT_SHORT_ENUMS,			\
   TARGET_BUILTIN_SETJMP_FRAME_VALUE,		\
   TARGET_MD_ASM_CLOBBERS,			\

gcc/target.h

@@ -485,6 +485,11 @@ struct gcc_target
   void * (* get_pch_validity) (size_t *);
   const char * (* pch_valid_p) (const void *, size_t);
 
+  /* If nonnull, this function checks whether a PCH file with the
+     given set of target flags can be used.  It returns NULL if so,
+     otherwise it returns an error message.  */
+  const char *(*check_pch_target_flags) (int);
+
   /* True if the compiler should give an enum type only as many
      bytes as it takes to represent the range of possible values of
      that type.  */

gcc/toplev.c

@@ -1487,6 +1487,7 @@ default_pch_valid_p (const void *data_p, size_t len)
   const char *data = (const char *)data_p;
   const char *flag_that_differs = NULL;
   size_t i;
+  int tf;
 
   /* -fpic and -fpie also usually make a PCH invalid.  */
   if (data[0] != flag_pic)
@@ -1496,11 +1497,15 @@ default_pch_valid_p (const void *data_p, size_t len)
   data += 2;
 
   /* Check target_flags.  */
-  if (memcmp (data, &target_flags, sizeof (target_flags)) != 0)
+  memcpy (&tf, data, sizeof (target_flags));
+  if (targetm.check_pch_target_flags)
+    {
+      const char *r = targetm.check_pch_target_flags (tf);
+      if (r != NULL)
+	return r;
+    }
+  else if (tf != target_flags)
     {
-      int tf;
-
-      memcpy (&tf, data, sizeof (target_flags));
 #ifdef TARGET_SWITCHES
       for (i = 0; i < ARRAY_SIZE (target_switches); i++)
 	{