re PR fortran/29396 (segfault with character pointer association)

2007-09-16  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/29396
	PR fortran/29606
	PR fortran/30625
	PR fortran/30871
	* trans.h : Add extra argument to gfc_build_array_ref. Rename
	gfc_conv_aliased_arg to gfc_conv_subref_array_arg.  Move
	prototype of is_aliased_array to gfortran.h and rename it
	gfc_is_subref_array.  Add field span to lang_decl, add a new
	decl lang specific flag accessed by GFC_DECL_SUBREF_ARRAY_P
	and a new type flag GFC_DECL_SUBREF_ARRAY_P.
	* trans.c (gfc_build_array_ref): Add the new argument, decl.
	If this is a subreference array pointer, use the lang_decl
	field 'span' to calculate the offset in bytes and use pointer
	arithmetic to address the element.
	* trans-array.c (gfc_conv_scalarized_array_ref,
	gfc_conv_array_ref): Add the backend declaration as the third
	field, if it is likely to be a subreference array pointer.
	(gfc_conv_descriptor_dimension, gfc_trans_array_ctor_element,
	gfc_trans_array_constructor_element, structure_alloc_comps,
	gfc_conv_array_index_offset): For all other references to
	gfc_build_array_ref, set the third argument to NULL.
	(gfc_get_dataptr_offset): New function.
	(gfc_conv_expr_descriptor): If the rhs of a pointer assignment
	is a subreference array, then calculate the offset to the
	subreference of the first element and set the descriptor data
	pointer to this, using gfc_get_dataptr_offset.
	trans-expr.c (gfc_get_expr_charlen): Use the expression for the
	character length for a character subreference.
	(gfc_conv_substring, gfc_conv_subref_array_arg): Add NULL for
	third argument in call to gfc_build_array_ref.
	(gfc_conv_aliased_arg): Rename to gfc_conv_subref_array_arg.
	(is_aliased_array): Remove.
	(gfc_conv_function_call): Change reference to is_aliased_array
	to gfc_is_subref_array and reference to gfc_conv_aliased_arg to
	gfc_conv_subref_array_arg.
	(gfc_trans_pointer_assignment): Add the array element length to
	the lang_decl 'span' field.
	* gfortran.h : Add subref_array_pointer to symbol_attribute and
	add the prototype for gfc_is_subref_array.
	* trans-stmt.c : Add NULL for third argument in all references
	to gfc_build_array_ref.
	* expr.c (gfc_is_subref_array): Renamed is_aliased_array.
	If this is a subreference array pointer, return true.
	(gfc_check_pointer_assign): If the rhs is a subreference array,
	set the lhs subreference_array_pointer attribute.
	* trans-decl.c (gfc_get_symbol_decl): Allocate the lang_decl
	field if the symbol is a subreference array pointer and set an
	initial value of zero for the 'span' field.
	* trans-io.c (set_internal_unit): Refer to is_subref_array and
	gfc_conv_subref_array_arg.
	(nml_get_addr_expr): Add NULL third argument to
	gfc_build_array_ref. 
	(gfc_trans_transfer): Use the scalarizer for a subreference
	array.

2007-09-16  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/29396
	PR fortran/29606
	PR fortran/30625
	PR fortran/30871
	* gfortran.dg/subref_array_pointer_1.f90: New test.
	* gfortran.dg/subref_array_pointer_2.f90: New test.

From-SVN: r128523

1 files changed, 25 insertions, 2 deletions

diff --git a/gcc/fortran/trans.c b/gcc/fortran/trans.c
index b9fd2df..0d036aa 100644
--- a/gcc/fortran/trans.c
+++ b/gcc/fortran/trans.c
@@ -309,9 +309,11 @@ gfc_build_addr_expr (tree type, tree t)
 /* Build an ARRAY_REF with its natural type.  */
 
 tree
-gfc_build_array_ref (tree base, tree offset)
+gfc_build_array_ref (tree base, tree offset, tree decl)
 {
   tree type = TREE_TYPE (base);
+  tree tmp;
+
   gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
   type = TREE_TYPE (type);
 
@@ -321,7 +323,28 @@ gfc_build_array_ref (tree base, tree offset)
   /* Strip NON_LVALUE_EXPR nodes.  */
   STRIP_TYPE_NOPS (offset);
 
-  return build4 (ARRAY_REF, type, base, offset, NULL_TREE, NULL_TREE);
+  /* If the array reference is to a pointer, whose target contains a
+     subreference, use the span that is stored with the backend decl
+     and reference the element with pointer arithmetic.  */
+  if (decl && (TREE_CODE (decl) == FIELD_DECL
+		 || TREE_CODE (decl) == VAR_DECL
+		 || TREE_CODE (decl) == PARM_DECL)
+	&& GFC_DECL_SUBREF_ARRAY_P (decl)
+	&& !integer_zerop (GFC_DECL_SPAN(decl)))
+    {
+      offset = fold_build2 (MULT_EXPR, gfc_array_index_type,
+			    offset, GFC_DECL_SPAN(decl));
+      tmp = gfc_build_addr_expr (pvoid_type_node, base);
+      tmp = fold_build2 (POINTER_PLUS_EXPR, pvoid_type_node,
+			 tmp, fold_convert (sizetype, offset));
+      tmp = fold_convert (build_pointer_type (type), tmp);
+      if (!TYPE_STRING_FLAG (type))
+	tmp = build_fold_indirect_ref (tmp);
+      return tmp;
+    }
+  else
+    /* Otherwise use a straightforward array reference.  */
+    return build4 (ARRAY_REF, type, base, offset, NULL_TREE, NULL_TREE);
 }