Re: [PATCH] Update TARGET_LIBCALL_VALUE target hook

[Anatoly Sokolov]

Hi.

> On 10/07/2009 11:35 AM, Anatoly Sokolov wrote:
>> Hello.
>>
>>    This patch change default_libcall_value function to don't use 
>> LIBCALL_VALUE
>> macro if it is not defined.  This will allow consistently, target by target,
>> move to use TARGET_LIBCALL_VALUE instead of LIBCALL_VALUE.

> Did you want to return NULL,

  No, I don't want to return NULL. Use 'return NULL_RTX' make code more
type-safe and self documented.

> or should that be gcc_unreachable?

  Yes, I agree. Doing so, we specify that TARGET_LIBCALL_VALUE target hook is
mandatory on all machines.

  Additional, I suggest to use gcc_unreachable in default_function_value if
FUNCTION_VALUE macro not defined.



        * targhooks.c (default_libcall_value): Don't use LIBCALL_VALUE macro
        if not defined. Change type of second argument to const_rtx.
        (default_function_value): Call gcc_unreachable if FUNCTION_VALUE
        macro not defined.
        * targhooks.h (default_libcall_value): Update prototype.
        * target.h (struct gcc_target): Change type of second argument of
        libcall_value to const_rtx.
        * config/arm/arm.c (arm_libcall_value): Change type of second argument
        to const_rtx.
        (arm_libcall_uses_aapcs_base): Change type of argument to const_rtx.
        * doc/tm.texi (TARGET_LIBCALL_VALUE):  Revise documentation.


Index: gcc/doc/tm.texi
===================================================================
--- gcc/doc/tm.texi     (revision 152618)
+++ gcc/doc/tm.texi     (working copy)
@@ -4394,7 +4394,7 @@
 @end defmac
 
 @deftypefn {Target Hook} rtx TARGET_LIBCALL_VALUE (enum machine_mode
-@var{mode}, rtx @var{fun})
+@var{mode}, const_rtx @var{fun})
 Define this hook if the back-end needs to know the name of the libcall
 function in order to determine where the result should be returned.  
 
Index: gcc/targhooks.c
===================================================================
--- gcc/targhooks.c     (revision 152618)
+++ gcc/targhooks.c     (working copy)
@@ -603,14 +603,19 @@
 #ifdef FUNCTION_VALUE
   return FUNCTION_VALUE (ret_type, fn_decl_or_type);
 #else
-  return NULL_RTX;
+  gcc_unreachable ();
 #endif
 }
 
 rtx
-default_libcall_value (enum machine_mode mode, rtx fun ATTRIBUTE_UNUSED)
+default_libcall_value (enum machine_mode mode ATTRIBUTE_UNUSED,
+                      const_rtx fun ATTRIBUTE_UNUSED)
 {
+#ifdef LIBCALL_VALUE
   return LIBCALL_VALUE (mode);
+#else
+  gcc_unreachable ();
+#endif
 }
 
 rtx
Index: gcc/targhooks.h
===================================================================
--- gcc/targhooks.h     (revision 152618)
+++ gcc/targhooks.h     (working copy)
@@ -98,7 +98,7 @@
   (const_tree, const_tree, const_tree);
 extern bool hook_bool_const_rtx_commutative_p (const_rtx, int);
 extern rtx default_function_value (const_tree, const_tree, bool);
-extern rtx default_libcall_value (enum machine_mode, rtx);
+extern rtx default_libcall_value (enum machine_mode, const_rtx);
 extern rtx default_internal_arg_pointer (void);
 extern rtx default_static_chain (const_tree, bool);
 extern void default_trampoline_init (rtx, tree, rtx);
Index: gcc/target.h
===================================================================
--- gcc/target.h        (revision 152618)
+++ gcc/target.h        (working copy)
@@ -908,7 +908,7 @@
 
     /* Return the rtx for the result of a libcall of mode MODE,
        calling the function FN_NAME.  */
-    rtx (*libcall_value) (enum machine_mode, rtx);
+    rtx (*libcall_value) (enum machine_mode, const_rtx);
 
     /* Return an rtx for the argument pointer incoming to the
        current function.  */
Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c        (revision 152618)
+++ gcc/config/arm/arm.c        (working copy)
@@ -133,7 +133,7 @@
                                                    const_tree, int);
 static bool arm_return_in_memory (const_tree, const_tree);
 static rtx arm_function_value (const_tree, const_tree, bool);
-static rtx arm_libcall_value (enum machine_mode, rtx);
+static rtx arm_libcall_value (enum machine_mode, const_rtx);
 
 static void arm_internal_label (FILE *, const char *, unsigned long);
 static void arm_output_mi_thunk (FILE *, tree, HOST_WIDE_INT, HOST_WIDE_INT,
@@ -3264,7 +3264,7 @@
 }
 
 static bool
-arm_libcall_uses_aapcs_base (rtx libcall)
+arm_libcall_uses_aapcs_base (const_rtx libcall)
 {
   static bool init_done = false;
   static htab_t libcall_htab;
@@ -3311,7 +3311,7 @@
 }
 
 rtx
-arm_libcall_value (enum machine_mode mode, rtx libcall)
+arm_libcall_value (enum machine_mode mode, const_rtx libcall)
 {
   if (TARGET_AAPCS_BASED && arm_pcs_default != ARM_PCS_AAPCS
       && GET_MODE_CLASS (mode) == MODE_FLOAT)


Anatoly.