[Ada] Plug loophole in warn_on_field_placement

Message ID 2202697.YcyMOAgK1I@polaris
State New
Headers show
Series
  • [Ada] Plug loophole in warn_on_field_placement
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Commit Message

Eric Botcazou June 12, 2018, 10:01 a.m.
Only the first component of a group of reordered bitfields was warned about.

Tested on x86-64/Linux, applied on mainline and 8 branch.


2018-06-12  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/decl.c (warn_on_field_placement): Use specific wording
	for discriminants.
	(warn_on_list_placement): New static function.
	(components_to_record): Use it to warn on multiple fields in list.

Patch

Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 261479)
+++ gcc-interface/decl.c	(working copy)
@@ -7296,31 +7296,44 @@  warn_on_field_placement (tree gnu_field,
   if (!Comes_From_Source (gnat_record_type))
     return;
 
+  Entity_Id gnat_field
+    = gnu_field_to_gnat (gnu_field, gnat_component_list, gnat_record_type);
+  gcc_assert (Present (gnat_field));
+
   const char *msg1
     = in_variant
       ? "?variant layout may cause performance issues"
       : "?record layout may cause performance issues";
   const char *msg2
-    = field_has_self_size (gnu_field)
-      ? "?component & whose length depends on a discriminant"
-      : field_has_variable_size (gnu_field)
-	? "?component & whose length is not fixed"
-	: "?component & whose length is not multiple of a byte";
+    = Ekind (gnat_field) == E_Discriminant
+      ? "?discriminant & whose length is not multiple of a byte"
+      : field_has_self_size (gnu_field)
+	? "?component & whose length depends on a discriminant"
+	: field_has_variable_size (gnu_field)
+	  ? "?component & whose length is not fixed"
+	  : "?component & whose length is not multiple of a byte";
   const char *msg3
     = do_reorder
       ? "?comes too early and was moved down"
       : "?comes too early and ought to be moved down";
 
-  Entity_Id gnat_field
-    = gnu_field_to_gnat (gnu_field, gnat_component_list, gnat_record_type);
-
-  gcc_assert (Present (gnat_field));
-
   post_error (msg1, gnat_field);
   post_error_ne (msg2, gnat_field, gnat_field);
   post_error (msg3, gnat_field);
 }
 
+/* Likewise but for every field present on GNU_FIELD_LIST.  */
+
+static void
+warn_on_list_placement (tree gnu_field_list, Node_Id gnat_component_list,
+		        Entity_Id gnat_record_type, bool in_variant,
+		        bool do_reorder)
+{
+  for (tree gnu_tmp = gnu_field_list; gnu_tmp; gnu_tmp = DECL_CHAIN (gnu_tmp))
+    warn_on_field_placement (gnu_tmp, gnat_component_list, gnat_record_type,
+			     in_variant, do_reorder);
+}
+
 /* Structure holding information for a given variant.  */
 typedef struct vinfo
 {
@@ -7895,11 +7908,18 @@  components_to_record (Node_Id gnat_compo
 	      if (tmp_bitp_size != 0)
 		{
 		  if (w_reorder && tmp_last_reorder_field_type < 2)
-		    warn_on_field_placement (gnu_tmp_bitp_list
-					     ? gnu_tmp_bitp_list : gnu_last,
-					     gnat_component_list,
-					     gnat_record_type, in_variant,
-					     do_reorder);
+		    {
+		      if (gnu_tmp_bitp_list)
+			warn_on_list_placement (gnu_tmp_bitp_list,
+						gnat_component_list,
+						gnat_record_type, in_variant,
+						do_reorder);
+		      else
+			warn_on_field_placement (gnu_last,
+						 gnat_component_list,
+						 gnat_record_type, in_variant,
+						 do_reorder);
+		    }
 
 		  if (do_reorder)
 		    gnu_bitp_list = chainon (gnu_tmp_bitp_list, gnu_bitp_list);
@@ -7953,10 +7973,16 @@  components_to_record (Node_Id gnat_compo
       if (last_reorder_field_type == 2
 	  && tmp_bitp_size != 0
 	  && tmp_last_reorder_field_type < 2)
-	warn_on_field_placement (gnu_tmp_bitp_list
-				 ? gnu_tmp_bitp_list : gnu_field_list,
-				 gnat_component_list, gnat_record_type,
-				 in_variant, do_reorder);
+	{
+	  if (gnu_tmp_bitp_list)
+	    warn_on_list_placement (gnu_tmp_bitp_list,
+				    gnat_component_list, gnat_record_type,
+				    in_variant, do_reorder);
+	  else
+	    warn_on_field_placement (gnu_field_list,
+				     gnat_component_list, gnat_record_type,
+				     in_variant, do_reorder);
+	}
     }
 
   if (do_reorder)