Possible patch for pr62242

Louis Krupp louis.krupp@zoho.com
Wed Sep 9 07:37:00 GMT 2015


This was ... interesting.  There were a couple of problems that triggered ICEs.

This patch fixes the reported file (I made sure this time) and causes no regressions as far as I can tell.

Dominique ... merci de votre patience.

Louis

Index: gcc/fortran/ChangeLog
===================================================================
--- gcc/fortran/ChangeLog	(revision 227571)
+++ gcc/fortran/ChangeLog	(working copy)
@@ -1,3 +1,12 @@
+2015-09-08  Louis Krupp <louis.krupp@zoho.com>
+
+	PR fortran/62242
+	* trans-array.c (get_array_ctor_all_strlen): Don't store length
+	tree pointer unless we know it's necessary
+	(trans_array_constructor): Create new gfc_charlen instance so
+	context-specific length expression isn't shared
+	(gfc_add_loop_ss_code): Don't try to convert non-constant length
+
 2015-09-04  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	* intrinsic.h (gfc_simplify_mvbits): Remove.
Index: gcc/fortran/trans-array.c
===================================================================
--- gcc/fortran/trans-array.c	(revision 227571)
+++ gcc/fortran/trans-array.c	(working copy)
@@ -1836,7 +1836,9 @@ get_array_ctor_all_strlen (stmtblock_t *block, gfc
       gfc_add_block_to_block (block, &se.pre);
       gfc_add_block_to_block (block, &se.post);
 
-      e->ts.u.cl->backend_decl = *len;
+      /* TODO: No test cases failed when the "if (0)" was added.
+	 Is there a reason to put this back the way it was? */
+      if (0) e->ts.u.cl->backend_decl = *len;
     }
 }
 
@@ -2226,6 +2228,7 @@ trans_array_constructor (gfc_ss * ss, locus * wher
   if (expr->ts.type == BT_CHARACTER)
     {
       bool const_string;
+      gfc_charlen *new_cl;
 
       /* get_array_ctor_strlen walks the elements of the constructor, if a
 	 typespec was given, we already know the string length and want the one
@@ -2251,8 +2254,36 @@ trans_array_constructor (gfc_ss * ss, locus * wher
 	 and not end up here.  */
       gcc_assert (ss_info->string_length);
 
-      expr->ts.u.cl->backend_decl = ss_info->string_length;
+      /* get_array_ctor_strlen can create a temporary variable in the
+	 current context which will be part of string_length.  If we share
+	 the resulting gfc_charlen structure with a variable in a different
+	 declaration context, we could trip the assertion in
+	 expand_expr_real_1 when it sees that the temporary has been
+	 created in one context and referenced in another:
 
+	   if (exp)
+	     context = decl_function_context (exp);
+	   gcc_assert (!exp
+		  || SCOPE_FILE_SCOPE_P (context)
+		  || context == current_function_decl
+		  || TREE_STATIC (exp)
+		  || DECL_EXTERNAL (exp)
+		  // ??? C++ creates functions that are not TREE_STATIC.
+		  || TREE_CODE (exp) == FUNCTION_DECL);
+
+	 So we create a new gfc_charlen structure and link it into what
+	 looks like the current namespace.
+
+	 TODO:  Can we do this only when get_array_ctor_strlen has been
+	 called?  Does it matter?  Are we using the right namespace (and
+	 does it matter, as long as the gfc_charlen structure is cleaned
+	 up)?
+      */
+
+      new_cl = gfc_new_charlen (gfc_current_ns, expr->ts.u.cl);
+      new_cl->backend_decl = ss_info->string_length;
+      expr->ts.u.cl = new_cl;
+
       type = gfc_get_character_type_len (expr->ts.kind, ss_info->string_length);
       if (const_string)
 	type = build_pointer_type (type);
@@ -2589,7 +2620,8 @@ gfc_add_loop_ss_code (gfc_loopinfo * loop, gfc_ss
 	  if (expr->ts.type == BT_CHARACTER
 	      && ss_info->string_length == NULL
 	      && expr->ts.u.cl
-	      && expr->ts.u.cl->length)
+	      && expr->ts.u.cl->length
+	      && expr->ts.u.cl->length->expr_type == EXPR_CONSTANT)
 	    {
 	      gfc_init_se (&se, NULL);
 	      gfc_conv_expr_type (&se, expr->ts.u.cl->length,
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