[patch, fortran] Partial fix for PR97454, declarations of some library functions

[patch, fortran] Partial fix for PR97454, declarations of some library functions

[Thomas Koenig]

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Hello world,

here's a patch which corrects some wrong declarations (and fixes
the segfault for FINDLOC on Darwin ARM).

Regression-tested. OK for trunk?

Best regards

	Thomas

Correct decls for functions which do not pass actual arguments.

A wrong decl for findloc caused segfaults at runtime on
Darwin for ARM; however, this is only a symptom of a larger
disease: The declarations for our library functions are often
inconsistent.  This patch solves that problem for the functions
specifically for the functions for which we do not pass optional
arguments, i.e. findloc and (min|max)loc.

It works by saving the symbols of the specific functions in
gfc_intrinsic_namespace and by generating the formal argument
lists from the actual argument lists.  Because symbols are
re-used, so are the backend decls.

gcc/fortran/ChangeLog:

	PR fortran/97454
	* gfortran.h (gfc_symbol): Add pass_as_value flag.
	(gfc_copy_formal_args_intr): Add optional argument
	copy_type.
	(gfc_get_intrinsic_function_symbol): Add prototype.
	(gfc_find_intrinsic_symbol): Add prototype.
	* intrinsic.c (gfc_get_intrinsic_function_symbol): New function.
	(gfc_find_intrinsic_symbol): New function.
	* symbol.c (gfc_copy_formal_args_intr): Add argument. Handle case
	where the type needs to be copied from the actual argument.
	* trans-intrinsic.c (remove_empty_actual_arguments): New function.
	(specific_intrinsic_symbol): New function.
	(gfc_conv_intrinsic_funcall): Use it.
	(strip_kind_from_actual): Adjust so that the expression pointer
	is set to NULL.
	(gfc_conv_intrinsic_minmaxloc): Likewise.
	(gfc_conv_intrinsic_minmaxval): Adjust removal of dim.
	* trans-types.c (gfc_sym_type): If sym->pass_as_value is set, do
	not pass by reference.

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diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index d0cea838444..37fed61a679 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -1664,6 +1664,9 @@ typedef struct gfc_symbol
   /* Set if the dummy argument of a procedure could be an array despite
      being called with a scalar actual argument. */
   unsigned maybe_array:1;
+  /* Set if this should be passed by value, but is not a VALUE argument
+     according to the Fortran standard.  */
+  unsigned pass_as_value:1;
 
   int refs;
   struct gfc_namespace *ns;	/* namespace containing this symbol */
@@ -3239,7 +3242,7 @@ bool gfc_type_is_extension_of (gfc_symbol *, gfc_symbol *);
 bool gfc_type_compatible (gfc_typespec *, gfc_typespec *);
 
 void gfc_copy_formal_args_intr (gfc_symbol *, gfc_intrinsic_sym *,
-				gfc_actual_arglist *);
+				gfc_actual_arglist *, bool copy_type = false);
 
 void gfc_free_finalizer (gfc_finalizer *el); /* Needed in resolve.c, too  */
 
@@ -3264,6 +3267,8 @@ void gfc_intrinsic_done_1 (void);
 
 char gfc_type_letter (bt, bool logical_equals_int = false);
 gfc_symbol * gfc_get_intrinsic_sub_symbol (const char *);
+gfc_symbol *gfc_get_intrinsic_function_symbol (gfc_expr *);
+gfc_symbol *gfc_find_intrinsic_symbol (gfc_expr *);
 bool gfc_convert_type (gfc_expr *, gfc_typespec *, int);
 bool gfc_convert_type_warn (gfc_expr *, gfc_typespec *, int, int,
 			    bool array = false);
diff --git a/gcc/fortran/intrinsic.c b/gcc/fortran/intrinsic.c
index ef33587a774..938a2f3606b 100644
--- a/gcc/fortran/intrinsic.c
+++ b/gcc/fortran/intrinsic.c
@@ -122,6 +122,43 @@ gfc_get_intrinsic_sub_symbol (const char *name)
   return sym;
 }
 
+/* Get a symbol for a resolved function, with its special name.  The
+   actual argument list needs to be set by the caller.  */
+
+gfc_symbol *
+gfc_get_intrinsic_function_symbol (gfc_expr *expr)
+{
+  gfc_symbol *sym;
+
+  gfc_get_symbol (expr->value.function.name, gfc_intrinsic_namespace, &sym);
+  sym->attr.external = 1;
+  sym->attr.function = 1;
+  sym->attr.always_explicit = 1;
+  sym->attr.proc = PROC_INTRINSIC;
+  sym->attr.flavor = FL_PROCEDURE;
+  sym->result = sym;
+  if (expr->rank > 0)
+    {
+      sym->attr.dimension = 1;
+      sym->as = gfc_get_array_spec ();
+      sym->as->type = AS_ASSUMED_SHAPE;
+      sym->as->rank = expr->rank;
+    }
+  return sym;
+}
+
+/* Find a symbol for a resolved intrinsic procedure, return NULL if
+   not found.  */
+
+gfc_symbol *
+gfc_find_intrinsic_symbol (gfc_expr *expr)
+{
+  gfc_symbol *sym;
+  gfc_find_symbol (expr->value.function.name, gfc_intrinsic_namespace,
+		   0, &sym);
+  return sym;
+}
+
 
 /* Return a pointer to the name of a conversion function given two
    typespecs.  */
diff --git a/gcc/fortran/symbol.c b/gcc/fortran/symbol.c
index df1e8965daa..a112c813124 100644
--- a/gcc/fortran/symbol.c
+++ b/gcc/fortran/symbol.c
@@ -4645,12 +4645,13 @@ add_proc_interface (gfc_symbol *sym, ifsrc source, gfc_formal_arglist *formal)
    declaration statement (see match_proc_decl()) to create the formal
    args based on the args of a given named interface.
 
-   When an actual argument list is provided, skip the absent arguments.
+   When an actual argument list is provided, skip the absent arguments
+   unless copy_type is true.
    To be used together with gfc_se->ignore_optional.  */
 
 void
 gfc_copy_formal_args_intr (gfc_symbol *dest, gfc_intrinsic_sym *src,
-			   gfc_actual_arglist *actual)
+			   gfc_actual_arglist *actual, bool copy_type)
 {
   gfc_formal_arglist *head = NULL;
   gfc_formal_arglist *tail = NULL;
@@ -4677,13 +4678,27 @@ gfc_copy_formal_args_intr (gfc_symbol *dest, gfc_intrinsic_sym *src,
 	      act_arg = act_arg->next;
 	      continue;
 	    }
-	  act_arg = act_arg->next;
 	}
       formal_arg = gfc_get_formal_arglist ();
       gfc_get_symbol (curr_arg->name, gfc_current_ns, &(formal_arg->sym));
 
       /* May need to copy more info for the symbol.  */
-      formal_arg->sym->ts = curr_arg->ts;
+      if (copy_type && act_arg->expr != NULL)
+	{
+	  formal_arg->sym->ts = act_arg->expr->ts;
+	  if (act_arg->expr->rank > 0)
+	    {
+	      formal_arg->sym->attr.dimension = 1;
+	      formal_arg->sym->as = gfc_get_array_spec();
+	      formal_arg->sym->as->rank = -1;
+	      formal_arg->sym->as->type = AS_ASSUMED_RANK;
+	    }
+	  if (act_arg->name && strcmp (act_arg->name, "%VAL") == 0)
+	    formal_arg->sym->pass_as_value = 1;
+	}
+      else
+	formal_arg->sym->ts = curr_arg->ts;
+
       formal_arg->sym->attr.optional = curr_arg->optional;
       formal_arg->sym->attr.value = curr_arg->value;
       formal_arg->sym->attr.intent = curr_arg->intent;
@@ -4708,6 +4723,8 @@ gfc_copy_formal_args_intr (gfc_symbol *dest, gfc_intrinsic_sym *src,
 
       /* Validate changes.  */
       gfc_commit_symbol (formal_arg->sym);
+      if (actual)
+	act_arg = act_arg->next;
     }
 
   /* Add the interface to the symbol.  */
diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index 8729bc12152..e0afc10d105 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -4238,12 +4238,60 @@ gfc_get_symbol_for_expr (gfc_expr * expr, bool ignore_optional)
   return sym;
 }
 
+/* Remove empty actual arguments.  */
+
+static void
+remove_empty_actual_arguments (gfc_actual_arglist **ap)
+{
+  while (*ap)
+    {
+      if ((*ap)->expr == NULL)
+	{
+	  gfc_actual_arglist *r = *ap;
+	  *ap = r->next;
+	  r->next = NULL;
+	  gfc_free_actual_arglist (r);
+	}
+      else
+	ap = &((*ap)->next);
+    }
+}
+
+/* Generate the right symbol for the specific intrinsic function and
+ modify the expr accordingly.  This assumes that absent optional
+ arguments should be removed.  FIXME: This should be extended for
+ procedures which do not ignore optional arguments (PR 97454).  */
+
+gfc_symbol *
+specific_intrinsic_symbol (gfc_expr *expr)
+{
+  gfc_symbol *sym;
+
+  sym = gfc_find_intrinsic_symbol (expr);
+  if (sym == NULL)
+    {
+      sym = gfc_get_intrinsic_function_symbol (expr);
+      sym->ts = expr->ts;
+      if (sym->ts.type == BT_CHARACTER && sym->ts.u.cl)
+	sym->ts.u.cl = gfc_new_charlen (sym->ns, NULL);
+
+      gfc_copy_formal_args_intr (sym, expr->value.function.isym,
+				 expr->value.function.actual, true);
+      sym->backend_decl
+	= gfc_get_extern_function_decl (sym, expr->value.function.actual);
+    }
+  remove_empty_actual_arguments (&(expr->value.function.actual));
+
+  return sym;
+}
+
 /* Generate a call to an external intrinsic function.  */
 static void
 gfc_conv_intrinsic_funcall (gfc_se * se, gfc_expr * expr)
 {
   gfc_symbol *sym;
   vec<tree, va_gc> *append_args;
+  bool specific_symbol;
 
   gcc_assert (!se->ss || se->ss->info->expr == expr);
 
@@ -4252,7 +4300,28 @@ gfc_conv_intrinsic_funcall (gfc_se * se, gfc_expr * expr)
   else
     gcc_assert (expr->rank == 0);
 
-  sym = gfc_get_symbol_for_expr (expr, se->ignore_optional);
+  switch (expr->value.function.isym->id)
+    {
+    case GFC_ISYM_FINDLOC:
+    case GFC_ISYM_MAXLOC:
+    case GFC_ISYM_MINLOC:
+    case GFC_ISYM_MAXVAL:
+    case GFC_ISYM_MINVAL:
+      specific_symbol = true;
+      break;
+    default:
+      specific_symbol = false;
+    }
+
+  if (specific_symbol)
+    {
+      /* Need to copy here because specific_intrinsic_symbol modifies
+	 expr to omit the absent optional arguments.  */
+      expr = gfc_copy_expr (expr);
+      sym = specific_intrinsic_symbol (expr);
+    }
+  else
+    sym = gfc_get_symbol_for_expr (expr, se->ignore_optional);
 
   /* Calls to libgfortran_matmul need to be appended special arguments,
      to be able to call the BLAS ?gemm functions if required and possible.  */
@@ -4302,7 +4371,11 @@ gfc_conv_intrinsic_funcall (gfc_se * se, gfc_expr * expr)
 
   gfc_conv_procedure_call (se, sym, expr->value.function.actual, expr,
 			  append_args);
-  gfc_free_symbol (sym);
+
+  if (specific_symbol)
+    gfc_free_expr (expr);
+  else
+    gfc_free_symbol (sym);
 }
 
 /* ANY and ALL intrinsics. ANY->op == NE_EXPR, ALL->op == EQ_EXPR.
@@ -5081,12 +5154,10 @@ strip_kind_from_actual (gfc_actual_arglist * actual)
 {
   for (gfc_actual_arglist *a = actual; a; a = a->next)
     {
-      gfc_actual_arglist *b = a->next;
-      if (b && b->name && strcmp (b->name, "kind") == 0)
+      if (a && a->name && strcmp (a->name, "kind") == 0)
 	{
-	  a->next = b->next;
-	  b->next = NULL;
-	  gfc_free_actual_arglist (b);
+	  gfc_free_expr (a->expr);
+	  a->expr = NULL;
 	}
     }
 }
@@ -5224,20 +5295,17 @@ gfc_conv_intrinsic_minmaxloc (gfc_se * se, gfc_expr * expr, enum tree_code op)
 
   if (arrayexpr->ts.type == BT_CHARACTER)
     {
-      gfc_actual_arglist *a, *b;
+      gfc_actual_arglist *a;
       a = actual;
       strip_kind_from_actual (a);
-      while (a->next)
+      while (a)
 	{
-	  b = a->next;
-	  if (b->expr == NULL || strcmp (b->name, "dim") == 0)
+	  if (a->name && strcmp (a->name, "dim") == 0)
 	    {
-	      a->next = b->next;
-	      b->next = NULL;
-	      gfc_free_actual_arglist (b);
+	      gfc_free_expr (a->expr);
+	      a->expr = NULL;
 	    }
-	  else
-	    a = b;
+	  a = a->next;
 	}
       gfc_conv_intrinsic_funcall (se, expr);
       return;
@@ -5996,29 +6064,16 @@ gfc_conv_intrinsic_minmaxval (gfc_se * se, gfc_expr * expr, enum tree_code op)
 
   if (arrayexpr->ts.type == BT_CHARACTER)
     {
-      gfc_actual_arglist *a2, *a3;
-      a2 = actual->next;  /* dim */
-      a3 = a2->next;      /* mask */
-      if (a2->expr == NULL || expr->rank == 0)
+      gfc_actual_arglist *dim = actual->next;
+      if (expr->rank == 0 && dim->expr != 0)
 	{
-	  if (a3->expr == NULL)
-	    actual->next = NULL;
-	  else
-	    {
-	      actual->next = a3;
-	      a2->next = NULL;
-	    }
-	  gfc_free_actual_arglist (a2);
+	  gfc_free_expr (dim->expr);
+	  dim->expr = NULL;
 	}
-      else
-	if (a3->expr == NULL)
-	  {
-	    a2->next = NULL;
-	    gfc_free_actual_arglist (a3);
-	  }
       gfc_conv_intrinsic_funcall (se, expr);
       return;
     }
+
   type = gfc_typenode_for_spec (&expr->ts);
   /* Initialize the result.  */
   limit = gfc_create_var (type, "limit");
diff --git a/gcc/fortran/trans-types.c b/gcc/fortran/trans-types.c
index 17f3ccc1d4e..b15ea667411 100644
--- a/gcc/fortran/trans-types.c
+++ b/gcc/fortran/trans-types.c
@@ -2246,7 +2246,8 @@ gfc_sym_type (gfc_symbol * sym)
   else
     type = gfc_typenode_for_spec (&sym->ts, sym->attr.codimension);
 
-  if (sym->attr.dummy && !sym->attr.function && !sym->attr.value)
+  if (sym->attr.dummy && !sym->attr.function && !sym->attr.value
+      && !sym->pass_as_value)
     byref = 1;
   else
     byref = 0;

Re: [patch, fortran] Partial fix for PR97454, declarations of some library functions

[Thomas Koenig]

I wrote:

> Regression-tested. OK for trunk?

I will remove this part

-   When an actual argument list is provided, skip the absent arguments.
+   When an actual argument list is provided, skip the absent arguments
+   unless copy_type is true.
     To be used together with gfc_se->ignore_optional.  */

(which was true for an intermediate version of the patch)
before committing.

Regards

	Thomas

Re: [patch, fortran] Partial fix for PR97454, declarations of some library functions

[Thomas Koenig]

Hello world,

> here's a patch which corrects some wrong declarations (and fixes
> the segfault for FINDLOC on Darwin ARM).
> 
> Regression-tested. OK for trunk?

ping?

Regards

	Thomas

Re: [patch, fortran] Partial fix for PR97454, declarations of some library functions

[Paul Richard Thomas]

Hi Thomas,

OK for master.

Thanks for working on this one!

Paul


On Fri, 16 Oct 2020 at 20:33, Thomas Koenig via Fortran <fortran@gcc.gnu.org>
wrote:

> Hello world,
>
> here's a patch which corrects some wrong declarations (and fixes
> the segfault for FINDLOC on Darwin ARM).
>
> Regression-tested. OK for trunk?
>
> Best regards
>
>         Thomas
>
> Correct decls for functions which do not pass actual arguments.
>
> A wrong decl for findloc caused segfaults at runtime on
> Darwin for ARM; however, this is only a symptom of a larger
> disease: The declarations for our library functions are often
> inconsistent.  This patch solves that problem for the functions
> specifically for the functions for which we do not pass optional
> arguments, i.e. findloc and (min|max)loc.
>
> It works by saving the symbols of the specific functions in
> gfc_intrinsic_namespace and by generating the formal argument
> lists from the actual argument lists.  Because symbols are
> re-used, so are the backend decls.
>
> gcc/fortran/ChangeLog:
>
>         PR fortran/97454
>         * gfortran.h (gfc_symbol): Add pass_as_value flag.
>         (gfc_copy_formal_args_intr): Add optional argument
>         copy_type.
>         (gfc_get_intrinsic_function_symbol): Add prototype.
>         (gfc_find_intrinsic_symbol): Add prototype.
>         * intrinsic.c (gfc_get_intrinsic_function_symbol): New function.
>         (gfc_find_intrinsic_symbol): New function.
>         * symbol.c (gfc_copy_formal_args_intr): Add argument. Handle case
>         where the type needs to be copied from the actual argument.
>         * trans-intrinsic.c (remove_empty_actual_arguments): New function.
>         (specific_intrinsic_symbol): New function.
>         (gfc_conv_intrinsic_funcall): Use it.
>         (strip_kind_from_actual): Adjust so that the expression pointer
>         is set to NULL.
>         (gfc_conv_intrinsic_minmaxloc): Likewise.
>         (gfc_conv_intrinsic_minmaxval): Adjust removal of dim.
>         * trans-types.c (gfc_sym_type): If sym->pass_as_value is set, do
>         not pass by reference.
>


-- 
"If you can't explain it simply, you don't understand it well enough" -
Albert Einstein

Re: [patch, fortran] Partial fix for PR97454, declarations of some library functions

[Thomas Koenig]

Hi Paul,

> OK for master.

Committed, thanks.

> Thanks for working on this one!

There is still a lto to do (I left in this typo by
design :-), especially with cshift and friends.  Let's see
how far I can progress until gcc 11 with this one, if helping
out Nicolas with coarray stuff leaves me time for that.

Best regards

	Thomas