Re: [ARM] hard VFP calling convention support [1/3]

[Richard Earnshaw <rearnsha at arm dot com>]

This is the part of the patch that needs approval from another
maintainer.

	* target-def.h (TARGET_LIBCALL_VALUE): New hook.
	* target.h (gcc_target): Add libcall_value to table of call hooks.
	* targhooks.h (default_libcall_value): Default implementation.
	* targhooks.c (default_libcall_value): Likewise.
	* doc/tm.texi (TARGET_LIBCALL_VALUE): Document it.
	* optabs.c (expand_unop): Use it.
	* expr.h (hard_libcall_value): Pass the function RTX through.
	* calls.c (emit_library_call_value_1): Update call to 
	hard_libcall_value.
	* explow.c (hard_libcall_value): Use new target hook.

Index: doc/tm.texi
===================================================================
--- doc/tm.texi	(revision 142389)
+++ doc/tm.texi	(working copy)
@@ -4313,6 +4313,17 @@ The definition of @code{LIBRARY_VALUE} n
 data types, because none of the library functions returns such types.
 @end defmac
 
+@deftypefn {Target Hook} rtx TARGET_LIBCALL_VALUE (enum machine_mode
+@var{mode}, 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.  
+
+The mode of the result is given by @var{mode} and the name of the called
+library function is given by @var{fun}.  The hook should return an RTX 
+representing the place where the library function result will be returned.
+
+If this hook is not defined, then LIBCALL_VALUE will be used.
+
 @defmac FUNCTION_VALUE_REGNO_P (@var{regno})
 A C expression that is nonzero if @var{regno} is the number of a hard
 register in which the values of called function may come back.
Index: targhooks.c
===================================================================
--- targhooks.c	(revision 142389)
+++ targhooks.c	(working copy)
@@ -561,6 +561,12 @@ default_function_value (const_tree ret_t
 }
 
 rtx
+default_libcall_value (enum machine_mode mode, rtx fun ATTRIBUTE_UNUSED)
+{
+  return LIBCALL_VALUE (mode);
+}
+
+rtx
 default_internal_arg_pointer (void)
 {
   /* If the reg that the virtual arg pointer will be translated into is
Index: targhooks.h
===================================================================
--- targhooks.h	(revision 142389)
+++ targhooks.h	(working copy)
@@ -87,6 +87,7 @@ extern const char *hook_invalid_arg_for_
   (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_internal_arg_pointer (void);
 #ifdef IRA_COVER_CLASSES
 extern const enum reg_class *default_ira_cover_classes (void);
Index: optabs.c
===================================================================
--- optabs.c	(revision 142389)
+++ optabs.c	(working copy)
@@ -3300,7 +3300,8 @@ expand_unop (enum machine_mode mode, opt
       if (unoptab == ffs_optab || unoptab == clz_optab || unoptab == ctz_optab
 	  || unoptab == popcount_optab || unoptab == parity_optab)
 	outmode
-	    = GET_MODE (hard_libcall_value (TYPE_MODE (integer_type_node)));
+	  = GET_MODE (hard_libcall_value (TYPE_MODE (integer_type_node),
+					  optab_libfunc (unoptab, mode)));
 
       start_sequence ();
 
Index: target.h
===================================================================
--- target.h	(revision 142389)
+++ target.h	(working copy)
@@ -870,6 +870,10 @@ struct gcc_target
     rtx (*function_value) (const_tree ret_type, const_tree fn_decl_or_type,
 			   bool outgoing);
 
+    /* Return the rtx for the result of a libcall of mode MODE,
+       calling the function FN_NAME.  */
+    rtx (*libcall_value) (enum machine_mode, rtx);
+
     /* Return an rtx for the argument pointer incoming to the
        current function.  */
     rtx (*internal_arg_pointer) (void);
Index: expr.h
===================================================================
--- expr.h	(revision 142389)
+++ expr.h	(working copy)
@@ -751,7 +751,7 @@ extern void probe_stack_range (HOST_WIDE
 
 /* Return an rtx that refers to the value returned by a library call
    in its original home.  This becomes invalid if any more code is emitted.  */
-extern rtx hard_libcall_value (enum machine_mode);
+extern rtx hard_libcall_value (enum machine_mode, rtx);
 
 /* Return the mode desired by operand N of a particular bitfield
    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
Index: calls.c
===================================================================
--- calls.c	(revision 142389)
+++ calls.c	(working copy)
@@ -3758,7 +3758,7 @@ emit_library_call_value_1 (int retval, r
      cse'ing of library calls could delete a call and leave the pop.  */
   NO_DEFER_POP;
   valreg = (mem_value == 0 && outmode != VOIDmode
-	    ? hard_libcall_value (outmode) : NULL_RTX);
+	    ? hard_libcall_value (outmode, orgfun) : NULL_RTX);
 
   /* Stack must be properly aligned now.  */
   gcc_assert (!(stack_pointer_delta
Index: explow.c
===================================================================
--- explow.c	(revision 142389)
+++ explow.c	(working copy)
@@ -1491,9 +1491,9 @@ hard_function_value (const_tree valtype,
    in which a scalar value of mode MODE was returned by a library call.  */
 
 rtx
-hard_libcall_value (enum machine_mode mode)
+hard_libcall_value (enum machine_mode mode, rtx fun)
 {
-  return LIBCALL_VALUE (mode);
+  return targetm.calls.libcall_value (mode, fun);
 }
 
 /* Look up the tree code for a given rtx code
Index: target-def.h
===================================================================
--- target-def.h	(revision 142389)
+++ target-def.h	(working copy)
@@ -590,6 +590,7 @@
 #define TARGET_ARG_PARTIAL_BYTES hook_int_CUMULATIVE_ARGS_mode_tree_bool_0
 
 #define TARGET_FUNCTION_VALUE default_function_value
+#define TARGET_LIBCALL_VALUE default_libcall_value
 #define TARGET_INTERNAL_ARG_POINTER default_internal_arg_pointer
 #define TARGET_UPDATE_STACK_BOUNDARY NULL
 #define TARGET_GET_DRAP_RTX NULL
@@ -613,6 +614,7 @@
    TARGET_ARG_PARTIAL_BYTES,					\
    TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN,			\
    TARGET_FUNCTION_VALUE,					\
+   TARGET_LIBCALL_VALUE,					\
    TARGET_INTERNAL_ARG_POINTER,					\
    TARGET_UPDATE_STACK_BOUNDARY,				\
    TARGET_GET_DRAP_RTX,						\