PR c++/87137] GCC-8 Fix

https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01966.html
	PR c++/87137
	* stor-layout.c (place_field): Scan forwards to check last
	bitfield when ms_bitfield_placement is in effect.
	gcc/testsuite/
	* g++.dg/abi/pr87137.C: New.

From-SVN: r264119

gcc/ChangeLog

+2018-09-05  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/87137
+	* stor-layout.c (place_field): Scan forwards to check last
+	bitfield when ms_bitfield_placement is in effect.
+
 2018-09-05  Richard Biener  <rguenther@suse.de>
 
 	PR bootstrap/87225
@@ -236,7 +242,7 @@
 	* doc/invoke.texi (C Dialect Options): Ditto.
 
 2018-09-01  Gerald Pfeifer  <gerald@pfeifer.com>
-	
+
 	* doc/install.texi (Prerequisites): Adjust link mpfr.org.
 
 2018-08-31  Richard Biener  <rguenther@suse.de>

gcc/stor-layout.c

@@ -1686,14 +1686,21 @@ place_field (record_layout_info rli, tree field)
     {
       rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
 
-      /* If we ended a bitfield before the full length of the type then
-	 pad the struct out to the full length of the last type.  */
-      if ((DECL_CHAIN (field) == NULL
-	   || TREE_CODE (DECL_CHAIN (field)) != FIELD_DECL)
-	  && DECL_BIT_FIELD_TYPE (field)
+      /* If FIELD is the last field and doesn't end at the full length
+	 of the type then pad the struct out to the full length of the
+	 last type.  */
+      if (DECL_BIT_FIELD_TYPE (field)
 	  && !integer_zerop (DECL_SIZE (field)))
-	rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos,
-				  bitsize_int (rli->remaining_in_alignment));
+	{
+	  /* We have to scan, because non-field DECLS are also here.  */
+	  tree probe = field;
+	  while ((probe = DECL_CHAIN (probe)))
+	    if (TREE_CODE (probe) == FIELD_DECL)
+	      break;
+	  if (!probe)
+	    rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos,
+				      bitsize_int (rli->remaining_in_alignment));
+	}
 
       normalize_rli (rli);
     }

gcc/testsuite/ChangeLog

 2018-09-05   Pádraig Brady p@draigbrady.com
 
+	PR c++/87137
+	* g++.dg/abi/pr87137.C: New.
+
 	PR c++/87185
 	* g++.dg/pr87185.C: New.
 

gcc/testsuite/g++.dg/abi/pr87137.C

+// PR c++/87137
+
+// Empty macro args are undefined in C++ 98
+// { dg-do compile { target c++11 } }
+
+// We got confused by non-field decls separating bitfields when
+// ms_bitfield_layout was in effect.
+
+#if defined (__x86_64__) || defined (__i686__) || defined (__powerpc__)
+#define ATTRIB  __attribute__((ms_struct))
+#elif defined (__superh__)
+#define ATTRIB __attribute__((renesas))
+#else
+#define ATTRIB
+#endif
+
+#define DEFINE(NAME,BASE,THING)		\
+  struct ATTRIB NAME BASE {		\
+    unsigned one : 12;			\
+    THING				\
+    unsigned two : 4;			\
+  }
+
+template<unsigned I, unsigned J> struct Test;
+template<unsigned I> struct Test<I,I> {};
+
+#define TEST(NAME,BASE,THING)			\
+  DEFINE(NAME##_WITH,BASE,THING);		\
+  DEFINE(NAME##_WITHOUT,BASE,);			\
+  int NAME = sizeof (Test<sizeof(NAME##_WITH),sizeof (NAME##_WITHOUT)>)
+
+TEST(NSFun,,int fun (););
+TEST(SFun,,static int fun (););
+TEST(Tdef,,typedef int tdef;);
+
+TEST(Var,,static int var;);
+struct base { int f; };
+TEST(Use,:base,using base::f;);
+TEST(Tmpl,,template<unsigned> class X {};);
+TEST(TmplFN,,template<unsigned> void fu (););