Add ARM VFP ABI support to libffi.

From-SVN: r166032

libffi/ChangeLog

+2010-10-28  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	* src/arm/ffi.c (ffi_prep_args): Add VFP register argument handling
+	code, new parameter, and return value. Update comments.
+	(ffi_prep_cif_machdep): Add case for VFP struct return values. Add
+	call to layout_vfp_args().
+	(ffi_call_SYSV): Update declaration.
+	(ffi_call_VFP): New declaration.
+	(ffi_call): Add VFP struct return conditions. Call ffi_call_VFP()
+	when ABI is FFI_VFP.
+	(ffi_closure_VFP): New declaration.
+	(ffi_closure_SYSV_inner): Add new vfp_args parameter, update call to
+	ffi_prep_incoming_args_SYSV().
+	(ffi_prep_incoming_args_SYSV): Update parameters. Add VFP argument
+	case handling.
+	(ffi_prep_closure_loc): Pass ffi_closure_VFP to trampoline
+	construction under VFP hard-float.
+	(rec_vfp_type_p): New function.
+	(vfp_type_p): Same.
+	(place_vfp_arg): Same.
+	(layout_vfp_args): Same.
+	* src/arm/ffitarget.h (ffi_abi): Add FFI_VFP. Define FFI_DEFAULT_ABI
+	based on __ARM_PCS_VFP.
+	(FFI_EXTRA_CIF_FIELDS): Define for adding VFP hard-float specific
+	fields.
+	(FFI_TYPE_STRUCT_VFP_FLOAT): Define internally used type code.
+	(FFI_TYPE_STRUCT_VFP_DOUBLE): Same.
+	* src/arm/sysv.S (ffi_call_SYSV): Change call of ffi_prep_args() to
+	direct call. Move function pointer load upwards.
+	(ffi_call_VFP): New function.
+	(ffi_closure_VFP): Same.
+
+	* testsuite/lib/libffi-dg.exp (check-flags): New function.
+	(dg-skip-if): New function.
+	* testsuite/libffi.call/cls_double_va.c: Skip if target is arm*-*-*
+	and compiler options include -mfloat-abi=hard.
+	* testsuite/libffi.call/cls_longdouble_va.c: Same.
+
 2010-10-01  Jakub Jelinek  <jakub@redhat.com>
 
 	PR libffi/45677

libffi/src/arm/ffi.c

@@ -29,12 +29,20 @@
 
 #include <stdlib.h>
 
-/* ffi_prep_args is called by the assembly routine once stack space
-   has been allocated for the function's arguments */
+/* Forward declares. */
+static int vfp_type_p (ffi_type *);
+static void layout_vfp_args (ffi_cif *);
 
-void ffi_prep_args(char *stack, extended_cif *ecif)
+/* ffi_prep_args is called by the assembly routine once stack space
+   has been allocated for the function's arguments
+   
+   The vfp_space parameter is the load area for VFP regs, the return
+   value is cif->vfp_used (word bitset of VFP regs used for passing
+   arguments). These are only used for the VFP hard-float ABI.
+*/
+int ffi_prep_args(char *stack, extended_cif *ecif, float *vfp_space)
 {
-  register unsigned int i;
+  register unsigned int i, vi = 0;
   register void **p_argv;
   register char *argp;
   register ffi_type **p_arg;
@@ -54,6 +62,21 @@ void ffi_prep_args(char *stack, extended_cif *ecif)
     {
       size_t z;
 
+      /* Allocated in VFP registers. */
+      if (ecif->cif->abi == FFI_VFP
+	  && vi < ecif->cif->vfp_nargs && vfp_type_p (*p_arg))
+	{
+	  float* vfp_slot = vfp_space + ecif->cif->vfp_args[vi++];
+	  if ((*p_arg)->type == FFI_TYPE_FLOAT)
+	    *((float*)vfp_slot) = *((float*)*p_argv);
+	  else if ((*p_arg)->type == FFI_TYPE_DOUBLE)
+	    *((double*)vfp_slot) = *((double*)*p_argv);
+	  else
+	    memcpy(vfp_slot, *p_argv, (*p_arg)->size);
+	  p_argv++;
+	  continue;
+	}
+
       /* Align if necessary */
       if (((*p_arg)->alignment - 1) & (unsigned) argp) {
 	argp = (char *) ALIGN(argp, (*p_arg)->alignment);
@@ -103,13 +126,15 @@ void ffi_prep_args(char *stack, extended_cif *ecif)
 	  p_argv++;
 	  argp += z;
     }
-  
-  return;
+
+  /* Indicate the VFP registers used. */
+  return ecif->cif->vfp_used;
 }
 
 /* Perform machine dependent cif processing */
 ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
 {
+  int type_code;
   /* Round the stack up to a multiple of 8 bytes.  This isn't needed 
      everywhere, but it is on some platforms, and it doesn't harm anything
      when it isn't needed.  */
@@ -130,7 +155,14 @@ ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
       break;
 
     case FFI_TYPE_STRUCT:
-      if (cif->rtype->size <= 4)
+      if (cif->abi == FFI_VFP
+	  && (type_code = vfp_type_p (cif->rtype)) != 0)
+	{
+	  /* A Composite Type passed in VFP registers, either
+	     FFI_TYPE_STRUCT_VFP_FLOAT or FFI_TYPE_STRUCT_VFP_DOUBLE. */
+	  cif->flags = (unsigned) type_code;
+	}
+      else if (cif->rtype->size <= 4)
 	/* A Composite Type not larger than 4 bytes is returned in r0.  */
 	cif->flags = (unsigned)FFI_TYPE_INT;
       else
@@ -145,11 +177,18 @@ ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
       break;
     }
 
+  /* Map out the register placements of VFP register args.
+     The VFP hard-float calling conventions are slightly more sophisticated than
+     the base calling conventions, so we do it here instead of in ffi_prep_args(). */
+  if (cif->abi == FFI_VFP)
+    layout_vfp_args (cif);
+
   return FFI_OK;
 }
 
-extern void ffi_call_SYSV(void (*)(char *, extended_cif *), extended_cif *,
-			  unsigned, unsigned, unsigned *, void (*fn)(void));
+/* Prototypes for assembly functions, in sysv.S */
+extern void ffi_call_SYSV (void (*fn)(void), extended_cif *, unsigned, unsigned, unsigned *);
+extern void ffi_call_VFP (void (*fn)(void), extended_cif *, unsigned, unsigned, unsigned *);
 
 void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
 {
@@ -157,6 +196,8 @@ void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
 
   int small_struct = (cif->flags == FFI_TYPE_INT 
 		      && cif->rtype->type == FFI_TYPE_STRUCT);
+  int vfp_struct = (cif->flags == FFI_TYPE_STRUCT_VFP_FLOAT
+		    || cif->flags == FFI_TYPE_STRUCT_VFP_DOUBLE);
 
   ecif.cif = cif;
   ecif.avalue = avalue;
@@ -173,38 +214,51 @@ void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
     }
   else if (small_struct)
     ecif.rvalue = &temp;
+  else if (vfp_struct)
+    {
+      /* Largest case is double x 4. */
+      ecif.rvalue = alloca(32);
+    }
   else
     ecif.rvalue = rvalue;
 
   switch (cif->abi) 
     {
     case FFI_SYSV:
-      ffi_call_SYSV(ffi_prep_args, &ecif, cif->bytes, cif->flags, ecif.rvalue,
-		    fn);
+      ffi_call_SYSV (fn, &ecif, cif->bytes, cif->flags, ecif.rvalue);
+      break;
 
+    case FFI_VFP:
+      ffi_call_VFP (fn, &ecif, cif->bytes, cif->flags, ecif.rvalue);
       break;
+
     default:
       FFI_ASSERT(0);
       break;
     }
   if (small_struct)
     memcpy (rvalue, &temp, cif->rtype->size);
+  else if (vfp_struct)
+    memcpy (rvalue, ecif.rvalue, cif->rtype->size);
 }
 
 /** private members **/
 
 static void ffi_prep_incoming_args_SYSV (char *stack, void **ret,
-					 void** args, ffi_cif* cif);
+					 void** args, ffi_cif* cif, float *vfp_stack);
 
 void ffi_closure_SYSV (ffi_closure *);
 
+void ffi_closure_VFP (ffi_closure *);
+
 /* This function is jumped to by the trampoline */
 
 unsigned int
-ffi_closure_SYSV_inner (closure, respp, args)
+ffi_closure_SYSV_inner (closure, respp, args, vfp_args)
      ffi_closure *closure;
      void **respp;
      void *args;
+     void *vfp_args;
 {
   // our various things...
   ffi_cif       *cif;
@@ -219,7 +273,7 @@ ffi_closure_SYSV_inner (closure, respp, args)
    * a structure, it will re-set RESP to point to the
    * structure return address.  */
 
-  ffi_prep_incoming_args_SYSV(args, respp, arg_area, cif);
+  ffi_prep_incoming_args_SYSV(args, respp, arg_area, cif, vfp_args);
 
   (closure->fun) (cif, *respp, arg_area, closure->user_data);
 
@@ -229,10 +283,12 @@ ffi_closure_SYSV_inner (closure, respp, args)
 /*@-exportheader@*/
 static void 
 ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
-			    void **avalue, ffi_cif *cif)
+			    void **avalue, ffi_cif *cif,
+			    /* Used only under VFP hard-float ABI. */
+			    float *vfp_stack)
 /*@=exportheader@*/
 {
-  register unsigned int i;
+  register unsigned int i, vi = 0;
   register void **p_argv;
   register char *argp;
   register ffi_type **p_arg;
@@ -249,8 +305,16 @@ ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
   for (i = cif->nargs, p_arg = cif->arg_types; (i != 0); i--, p_arg++)
     {
       size_t z;
-
-      size_t alignment = (*p_arg)->alignment;
+      size_t alignment;
+  
+      if (cif->abi == FFI_VFP
+	  && vi < cif->vfp_nargs && vfp_type_p (*p_arg))
+	{
+	  *p_argv++ = (void*)(vfp_stack + cif->vfp_args[vi++]);
+	  continue;
+	}
+
+      alignment = (*p_arg)->alignment;
       if (alignment < 4)
 	alignment = 4;
       /* Align if necessary */
@@ -295,10 +359,17 @@ ffi_prep_closure_loc (ffi_closure* closure,
 		      void *user_data,
 		      void *codeloc)
 {
-  FFI_ASSERT (cif->abi == FFI_SYSV);
+  void (*closure_func)(ffi_closure*) = NULL;
 
+  if (cif->abi == FFI_SYSV)
+    closure_func = &ffi_closure_SYSV;
+  else if (cif->abi == FFI_VFP)
+    closure_func = &ffi_closure_VFP;
+  else
+    FFI_ASSERT (0);
+    
   FFI_INIT_TRAMPOLINE (&closure->tramp[0], \
-		       &ffi_closure_SYSV,  \
+		       closure_func,  \
 		       codeloc);
     
   closure->cif  = cif;
@@ -307,3 +378,123 @@ ffi_prep_closure_loc (ffi_closure* closure,
 
   return FFI_OK;
 }
+
+/* Below are routines for VFP hard-float support. */
+
+static int rec_vfp_type_p (ffi_type *t, int *elt, int *elnum)
+{
+  switch (t->type)
+    {
+    case FFI_TYPE_FLOAT:
+    case FFI_TYPE_DOUBLE:
+      *elt = (int) t->type;
+      *elnum = 1;
+      return 1;
+
+    case FFI_TYPE_STRUCT_VFP_FLOAT:
+      *elt = FFI_TYPE_FLOAT;
+      *elnum = t->size / sizeof (float);
+      return 1;
+
+    case FFI_TYPE_STRUCT_VFP_DOUBLE:
+      *elt = FFI_TYPE_DOUBLE;
+      *elnum = t->size / sizeof (double);
+      return 1;
+
+    case FFI_TYPE_STRUCT:;
+      {
+	int base_elt = 0, total_elnum = 0;
+	ffi_type **el = t->elements;
+	while (*el)
+	  {
+	    int el_elt = 0, el_elnum = 0;
+	    if (! rec_vfp_type_p (*el, &el_elt, &el_elnum)
+		|| (base_elt && base_elt != el_elt)
+		|| total_elnum + el_elnum > 4)
+	      return 0;
+	    base_elt = el_elt;
+	    total_elnum += el_elnum;
+	    el++;
+	  }
+	*elnum = total_elnum;
+	*elt = base_elt;
+	return 1;
+      }
+    default: ;
+    }
+  return 0;
+}
+
+static int vfp_type_p (ffi_type *t)
+{
+  int elt, elnum;
+  if (rec_vfp_type_p (t, &elt, &elnum))
+    {
+      if (t->type == FFI_TYPE_STRUCT)
+	{
+	  if (elnum == 1)
+	    t->type = elt;
+	  else
+	    t->type = (elt == FFI_TYPE_FLOAT
+		       ? FFI_TYPE_STRUCT_VFP_FLOAT
+		       : FFI_TYPE_STRUCT_VFP_DOUBLE);
+	}
+      return (int) t->type;
+    }
+  return 0;
+}
+
+static void place_vfp_arg (ffi_cif *cif, ffi_type *t)
+{
+  int reg = cif->vfp_reg_free;
+  int nregs = t->size / sizeof (float);
+  int align = ((t->type == FFI_TYPE_STRUCT_VFP_FLOAT
+		|| t->type == FFI_TYPE_FLOAT) ? 1 : 2);
+  /* Align register number. */
+  if ((reg & 1) && align == 2)
+    reg++;
+  while (reg + nregs <= 16)
+    {
+      int s, new_used = 0;
+      for (s = reg; s < reg + nregs; s++)
+	{
+	  new_used |= (1 << s);
+	  if (cif->vfp_used & (1 << s))
+	    {
+	      reg += align;
+	      goto next_reg;
+	    }
+	}
+      /* Found regs to allocate. */
+      cif->vfp_used |= new_used;
+      cif->vfp_args[cif->vfp_nargs++] = reg;
+
+      /* Update vfp_reg_free. */
+      if (cif->vfp_used & (1 << cif->vfp_reg_free))
+	{
+	  reg += nregs;
+	  while (cif->vfp_used & (1 << reg))
+	    reg += 1;
+	  cif->vfp_reg_free = reg;
+	}
+      return;
+    next_reg: ;
+    }
+}
+
+static void layout_vfp_args (ffi_cif *cif)
+{
+  int i;
+  /* Init VFP fields */
+  cif->vfp_used = 0;
+  cif->vfp_nargs = 0;
+  cif->vfp_reg_free = 0;
+  memset (cif->vfp_args, -1, 16); /* Init to -1. */
+
+  for (i = 0; i < cif->nargs; i++)
+    {
+      ffi_type *t = cif->arg_types[i];
+      if (vfp_type_p (t))
+	place_vfp_arg (cif, t);
+    }
+}

libffi/src/arm/ffitarget.h

 /* -----------------------------------------------------------------*-C-*-
    ffitarget.h - Copyright (c) 1996-2003  Red Hat, Inc.
+                 Copyright (c) 2010 CodeSourcery
+
    Target configuration macros for ARM.
 
    Permission is hereby granted, free of charge, to any person obtaining
@@ -34,11 +36,25 @@ typedef signed long            ffi_sarg;
 typedef enum ffi_abi {
   FFI_FIRST_ABI = 0,
   FFI_SYSV,
+  FFI_VFP,
+  FFI_LAST_ABI,
+#ifdef __ARM_PCS_VFP
+  FFI_DEFAULT_ABI = FFI_VFP,
+#else
   FFI_DEFAULT_ABI = FFI_SYSV,
-  FFI_LAST_ABI = FFI_DEFAULT_ABI + 1
+#endif
 } ffi_abi;
 #endif
 
+#define FFI_EXTRA_CIF_FIELDS			\
+  int vfp_used;					\
+  short vfp_reg_free, vfp_nargs;		\
+  signed char vfp_args[16]			\
+
+/* Internally used. */
+#define FFI_TYPE_STRUCT_VFP_FLOAT  (FFI_TYPE_LAST + 1)
+#define FFI_TYPE_STRUCT_VFP_DOUBLE (FFI_TYPE_LAST + 2)
+
 /* ---- Definitions for closures ----------------------------------------- */
 
 #define FFI_CLOSURES 1

libffi/src/arm/sysv.S

@@ -142,12 +142,11 @@ _L__\name:
 .endm
 
 
-	@ r0:   ffi_prep_args
+	@ r0:   fn
 	@ r1:   &ecif
 	@ r2:   cif->bytes
 	@ r3:   fig->flags
 	@ sp+0: ecif.rvalue
-	@ sp+4: fn
 
 	@ This assumes we are using gas.
 ARM_FUNC_START ffi_call_SYSV
@@ -162,24 +161,23 @@ ARM_FUNC_START ffi_call_SYSV
 	sub	sp, fp, r2
 
 	@ Place all of the ffi_prep_args in position
-	mov	ip, r0
 	mov	r0, sp
 	@     r1 already set
 
 	@ Call ffi_prep_args(stack, &ecif)
-	call_reg(ip)
+	bl	ffi_prep_args
 
 	@ move first 4 parameters in registers
 	ldmia	sp, {r0-r3}
 
 	@ and adjust stack
-	ldr	ip, [fp, #8]
-        cmp	ip, #16
-	movhs	ip, #16
-        add	sp, sp, ip
+	sub	lr, fp, sp	@ cif->bytes == fp - sp
+	ldr	ip, [fp]	@ load fn() in advance
+	cmp	lr, #16
+	movhs	lr, #16
+	add	sp, sp, lr
 
 	@ call (fn) (...)
-	ldr	ip, [fp, #28]
 	call_reg(ip)
 	
 	@ Remove the space we pushed for the args
@@ -230,6 +228,101 @@ LSYM(Lepilogue):
 	UNWIND .fnend
         .size    CNAME(ffi_call_SYSV),.ffi_call_SYSV_end-CNAME(ffi_call_SYSV)
 
+
+	@ r0:   fn
+	@ r1:   &ecif
+	@ r2:   cif->bytes
+	@ r3:   fig->flags
+	@ sp+0: ecif.rvalue
+
+ARM_FUNC_START ffi_call_VFP
+	@ Save registers
+        stmfd	sp!, {r0-r3, fp, lr}
+	UNWIND .save	{r0-r3, fp, lr}
+	mov	fp, sp
+	UNWIND .setfp	fp, sp
+
+	@ Make room for all of the new args.
+	sub	sp, sp, r2
+
+	@ Make room for loading VFP args
+	sub	sp, sp, #64
+
+	@ Place all of the ffi_prep_args in position
+	mov	r0, sp
+	@     r1 already set
+	sub	r2, fp, #64   @ VFP scratch space
+
+	@ Call ffi_prep_args(stack, &ecif, vfp_space)
+	bl	ffi_prep_args
+
+	@ Load VFP register args if needed
+	cmp	r0, #0
+	beq	LSYM(Lbase_args)
+
+	@ Load only d0 if possible
+	cmp	r0, #3
+	sub	ip, fp, #64
+	flddle	d0, [ip]
+	fldmiadgt	ip, {d0-d7}
+
+LSYM(Lbase_args):
+	@ move first 4 parameters in registers
+	ldmia	sp, {r0-r3}
+
+	@ and adjust stack
+	sub	lr, ip, sp	@ cif->bytes == (fp - 64) - sp
+	ldr	ip, [fp]	@ load fn() in advance
+        cmp	lr, #16
+	movhs	lr, #16
+        add	sp, sp, lr
+
+	@ call (fn) (...)
+	call_reg(ip)
+
+	@ Remove the space we pushed for the args
+	mov	sp, fp
+
+	@ Load r2 with the pointer to storage for
+	@ the return value
+	ldr	r2, [sp, #24]
+
+	@ Load r3 with the return type code 
+	ldr	r3, [sp, #12]
+
+	@ If the return value pointer is NULL,
+	@ assume no return value.
+	cmp	r2, #0
+	beq	LSYM(Lepilogue_vfp)
+	
+	cmp	r3, #FFI_TYPE_INT
+	streq	r0, [r2]
+	beq	LSYM(Lepilogue_vfp)
+
+	cmp	r3, #FFI_TYPE_SINT64
+	stmeqia	r2, {r0, r1}
+	beq	LSYM(Lepilogue_vfp)
+
+	cmp	r3, #FFI_TYPE_FLOAT
+	fstseq	s0, [r2]
+	beq	LSYM(Lepilogue_vfp)
+	
+	cmp	r3, #FFI_TYPE_DOUBLE
+	fstdeq	d0, [r2]
+	beq	LSYM(Lepilogue_vfp)
+
+	cmp	r3, #FFI_TYPE_STRUCT_VFP_FLOAT
+	cmpne	r3, #FFI_TYPE_STRUCT_VFP_DOUBLE
+	fstmiadeq	r2, {d0-d3}
+
+LSYM(Lepilogue_vfp):
+	RETLDM	"r0-r3,fp"
+
+.ffi_call_VFP_end:
+	UNWIND .fnend
+        .size    CNAME(ffi_call_VFP),.ffi_call_VFP_end-CNAME(ffi_call_VFP)
+	
+	
 /*
 	unsigned int FFI_HIDDEN
 	ffi_closure_SYSV_inner (closure, respp, args)
@@ -302,6 +395,68 @@ ARM_FUNC_START ffi_closure_SYSV
 	UNWIND .fnend
         .size    CNAME(ffi_closure_SYSV),.ffi_closure_SYSV_end-CNAME(ffi_closure_SYSV)
 
+
+ARM_FUNC_START ffi_closure_VFP
+	fstmfdd	sp!, {d0-d7}
+	@ r0-r3, then d0-d7
+	UNWIND .pad #80
+	add	ip, sp, #80
+	stmfd	sp!, {ip, lr}
+	UNWIND .save	{r0, lr}
+	add	r2, sp, #72
+	add	r3, sp, #8
+	.pad #72
+	sub	sp, sp, #72
+	str	sp, [sp, #64]
+	add	r1, sp, #64
+	bl	ffi_closure_SYSV_inner
+
+	cmp	r0, #FFI_TYPE_INT
+	beq	.Lretint_vfp
+
+	cmp	r0, #FFI_TYPE_FLOAT
+	beq	.Lretfloat_vfp
+
+	cmp	r0, #FFI_TYPE_DOUBLE
+	cmpne	r0, #FFI_TYPE_LONGDOUBLE
+	beq	.Lretdouble_vfp
+
+	cmp	r0, #FFI_TYPE_SINT64
+	beq	.Lretlonglong_vfp
+
+	cmp	r0, #FFI_TYPE_STRUCT_VFP_FLOAT
+	beq	.Lretfloat_struct_vfp
+
+	cmp	r0, #FFI_TYPE_STRUCT_VFP_DOUBLE
+	beq	.Lretdouble_struct_vfp
+	
+.Lclosure_epilogue_vfp:
+	add	sp, sp, #72
+	ldmfd	sp, {sp, pc}
+
+.Lretfloat_vfp:
+	flds	s0, [sp]
+	b	.Lclosure_epilogue_vfp
+.Lretdouble_vfp:
+	fldd	d0, [sp]
+	b	.Lclosure_epilogue_vfp
+.Lretint_vfp:
+	ldr	r0, [sp]
+	b	.Lclosure_epilogue_vfp
+.Lretlonglong_vfp:
+	ldmia	sp, {r0, r1}
+	b	.Lclosure_epilogue_vfp
+.Lretfloat_struct_vfp:
+	fldmiad	sp, {d0-d1}
+	b	.Lclosure_epilogue_vfp
+.Lretdouble_struct_vfp:
+	fldmiad	sp, {d0-d3}
+	b	.Lclosure_epilogue_vfp
+
+.ffi_closure_VFP_end:
+	UNWIND .fnend
+        .size    CNAME(ffi_closure_VFP),.ffi_closure_VFP_end-CNAME(ffi_closure_VFP)
+
 #if defined __ELF__ && defined __linux__
 	.section	.note.GNU-stack,"",%progbits
 #endif

libffi/testsuite/lib/libffi-dg.exp

@@ -272,6 +272,56 @@ proc dg-xfail-if { args } {
     }
 }
 
+proc check-flags { args } {
+
+    # The args are within another list; pull them out.
+    set args [lindex $args 0]
+
+    # The next two arguments are optional.  If they were not specified,
+    # use the defaults.
+    if { [llength $args] == 2 } {
+	lappend $args [list "*"]
+    }
+    if { [llength $args] == 3 } {
+	lappend $args [list ""]
+    }
+
+    # If the option strings are the defaults, or the same as the
+    # defaults, there is no need to call check_conditional_xfail to
+    # compare them to the actual options.
+    if { [string compare [lindex $args 2] "*"] == 0
+	 && [string compare [lindex $args 3] "" ] == 0 } {
+	set result 1    
+    } else {
+	# The target list might be an effective-target keyword, so replace
+	# the original list with "*-*-*", since we already know it matches.
+	set result [check_conditional_xfail [lreplace $args 1 1 "*-*-*"]]
+    }
+
+    return $result
+}
+
+proc dg-skip-if { args } {
+    # Verify the number of arguments.  The last two are optional.
+    set args [lreplace $args 0 0]
+    if { [llength $args] < 2 || [llength $args] > 4 } {
+        error "dg-skip-if 2: need 2, 3, or 4 arguments"
+    }
+
+    # Don't bother if we're already skipping the test.
+    upvar dg-do-what dg-do-what
+    if { [lindex ${dg-do-what} 1] == "N" } {
+      return
+    }
+
+    set selector [list target [lindex $args 1]]
+    if { [dg-process-target $selector] == "S" } {
+        if [check-flags $args] {
+            upvar dg-do-what dg-do-what
+            set dg-do-what [list [lindex ${dg-do-what} 0] "N" "P"]
+        }
+    }
+}
 
 # We need to make sure that additional_files and additional_sources
 # are both cleared out after every test.  It is not enough to clear

libffi/testsuite/libffi.call/cls_double_va.c

@@ -6,6 +6,8 @@
 
 /* { dg-do run { xfail strongarm*-*-* xscale*-*-* } } */
 /* { dg-output "" { xfail avr32*-*-* } } */
+/* { dg-skip-if "" arm*-*-* { "-mfloat-abi=hard" } { "" } } */
+
 #include "ffitest.h"
 
 static void

libffi/testsuite/libffi.call/cls_longdouble_va.c

@@ -6,6 +6,8 @@
 
 /* { dg-do run { xfail strongarm*-*-* xscale*-*-* } } */
 /* { dg-output "" { xfail avr32*-*-* x86_64-*-mingw* } } */
+/* { dg-skip-if "" arm*-*-* { "-mfloat-abi=hard" } { "" } } */
+
 #include "ffitest.h"
 
 static void