* cp-tree.h (CLEAR_DECL_C_BIT_FIELD): New macro.

	* class.c (check_bitfield_decl): Turn illegal bitfields into
	non-bitfields.
	(dfs_propagate_binfo_offsets): Adjust for new size_binop
	semantics.
	(dfs_offset_for_unshared_vbases): Likewise.
	* cvt.c (cp_convert_to_pointer): Convert NULL to a
	pointer-to-member correctly under the new ABI.
	* expr.c (cplus_expand_constant): Don't use cp_convert when
	turning an offset into a pointer-to-member.
	* init.c (resolve_offset_ref): Don't adjust pointers-to-members
	when dereferencing them under the new ABI.
	* typeck.c (get_member_function_from_ptrfunc): Tweak calculation
	of pointers-to-members under the new ABI.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@32631 138bc75d-0d04-0410-961f-82ee72b054a4

9 files changed, 161 insertions, 48 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 892a466bd2e..fbaaad904ca 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,20 @@
 2000-03-18  Mark Mitchell  <mark@codesourcery.com>
 
+	* cp-tree.h (CLEAR_DECL_C_BIT_FIELD): New macro.
+	* class.c (check_bitfield_decl): Turn illegal bitfields into
+	non-bitfields.
+	(dfs_propagate_binfo_offsets): Adjust for new size_binop
+	semantics.
+	(dfs_offset_for_unshared_vbases): Likewise.
+	* cvt.c (cp_convert_to_pointer): Convert NULL to a
+	pointer-to-member correctly under the new ABI.
+	* expr.c (cplus_expand_constant): Don't use cp_convert when
+	turning an offset into a pointer-to-member.
+	* init.c (resolve_offset_ref): Don't adjust pointers-to-members
+	when dereferencing them under the new ABI.
+	* typeck.c (get_member_function_from_ptrfunc): Tweak calculation
+	of pointers-to-members under the new ABI.
+	
 	* class.c (check_bitfield_decl): Remove restriction on really long
 	bitfields.
 	(layout_class_type): Implement new ABI handling of bitfields
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 5475ac4ba92..02424928d0d 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -3616,22 +3616,20 @@ check_bitfield_decl (field)
      tree field;
 {
   tree type = TREE_TYPE (field);
+  tree w = NULL_TREE;
 
-  /* Invalid bit-field size done by grokfield.  */
-  /* Detect invalid bit-field type. Simply checking if TYPE is
-     integral is insufficient, as that is the array core of the field
-     type. If TREE_TYPE (field) is integral, then TYPE must be the same.  */
+  /* Detect invalid bit-field type.  */
   if (DECL_INITIAL (field)
       && ! INTEGRAL_TYPE_P (TREE_TYPE (field)))
     {
       cp_error_at ("bit-field `%#D' with non-integral type", field);
-      DECL_INITIAL (field) = NULL;
+      w = error_mark_node;
     }
 
   /* Detect and ignore out of range field width.  */
   if (DECL_INITIAL (field))
     {
-      tree w = DECL_INITIAL (field);
+      w = DECL_INITIAL (field);
 
       /* Avoid the non_lvalue wrapper added by fold for PLUS_EXPRs.  */
       STRIP_NOPS (w);
@@ -3646,17 +3644,17 @@ check_bitfield_decl (field)
 	{
 	  cp_error_at ("bit-field `%D' width not an integer constant",
 		       field);
-	  DECL_INITIAL (field) = NULL_TREE;
+	  w = error_mark_node;
 	}
       else if (tree_int_cst_sgn (w) < 0)
 	{
-	  DECL_INITIAL (field) = NULL;
 	  cp_error_at ("negative width in bit-field `%D'", field);
+	  w = error_mark_node;
 	}
       else if (integer_zerop (w) && DECL_NAME (field) != 0)
 	{
-	  DECL_INITIAL (field) = NULL;
 	  cp_error_at ("zero width for bit-field `%D'", field);
+	  w = error_mark_node;
 	}
       else if (compare_tree_int (w, TYPE_PRECISION (type)) > 0
 	       && TREE_CODE (type) != ENUMERAL_TYPE
@@ -3672,30 +3670,37 @@ check_bitfield_decl (field)
 					      TREE_UNSIGNED (type)))))
 	cp_warning_at ("`%D' is too small to hold all values of `%#T'",
 		       field, type);
+    }
+  
+  /* Remove the bit-field width indicator so that the rest of the
+     compiler does not treat that value as an initializer.  */
+  DECL_INITIAL (field) = NULL_TREE;
 
-      if (DECL_INITIAL (field))
-	{
-	  DECL_INITIAL (field) = NULL_TREE;
-	  DECL_SIZE (field) = convert (bitsizetype, w);
-	  DECL_BIT_FIELD (field) = 1;
+  if (w != error_mark_node)
+    {
+      DECL_SIZE (field) = convert (bitsizetype, w);
+      DECL_BIT_FIELD (field) = 1;
 
-	  if (integer_zerop (w))
-	    {
+      if (integer_zerop (w))
+	{
 #ifdef EMPTY_FIELD_BOUNDARY
-	      DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
-					EMPTY_FIELD_BOUNDARY);
+	  DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
+				    EMPTY_FIELD_BOUNDARY);
 #endif
 #ifdef PCC_BITFIELD_TYPE_MATTERS
-	      if (PCC_BITFIELD_TYPE_MATTERS)
-		DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
-					  TYPE_ALIGN (type));
+	  if (PCC_BITFIELD_TYPE_MATTERS)
+	    DECL_ALIGN (field) = MAX (DECL_ALIGN (field), 
+				      TYPE_ALIGN (type));
 #endif
-	    }
 	}
     }
   else
-    /* Non-bit-fields are aligned for their type.  */
-    DECL_ALIGN (field) = MAX (DECL_ALIGN (field), TYPE_ALIGN (type));
+    {
+      /* Non-bit-fields are aligned for their type.  */
+      DECL_BIT_FIELD (field) = 0;
+      CLEAR_DECL_C_BIT_FIELD (field);
+      DECL_ALIGN (field) = MAX (DECL_ALIGN (field), TYPE_ALIGN (type));
+    }
 }
 
 /* FIELD is a non bit-field.  We are finishing the processing for its
@@ -4678,7 +4683,10 @@ dfs_propagate_binfo_offsets (binfo, data)
   tree offset = (tree) data;
 
   /* Update the BINFO_OFFSET for this base.  */
-  BINFO_OFFSET (binfo) = size_binop (PLUS_EXPR, BINFO_OFFSET (binfo), offset);
+  BINFO_OFFSET (binfo) = fold (build (PLUS_EXPR,
+				      sizetype,
+				      BINFO_OFFSET (binfo), 
+				      offset));
 
   SET_BINFO_MARKED (binfo);
 
@@ -4744,8 +4752,7 @@ dfs_set_offset_for_unshared_vbases (binfo, data)
       tree offset;
       
       vbase = BINFO_FOR_VBASE (BINFO_TYPE (binfo), t);
-      offset = size_binop (MINUS_EXPR, 
-			   BINFO_OFFSET (vbase), BINFO_OFFSET (binfo));
+      offset = size_diffop (BINFO_OFFSET (vbase), BINFO_OFFSET (binfo));
       propagate_binfo_offsets (binfo, offset);
     }
 
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index fd87926fd03..3e6f1c98066 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -2347,6 +2347,8 @@ extern int flag_new_for_scope;
    && DECL_LANG_SPECIFIC (NODE)->decl_flags.bitfield)
 #define SET_DECL_C_BIT_FIELD(NODE) \
   (DECL_LANG_SPECIFIC (FIELD_DECL_CHECK (NODE))->decl_flags.bitfield = 1)
+#define CLEAR_DECL_C_BIT_FIELD(NODE) \
+  (DECL_LANG_SPECIFIC (FIELD_DECL_CHECK (NODE))->decl_flags.bitfield = 0)
 
 /* In a FUNCTION_DECL, nonzero if the function cannot be inlined.  */
 #define DECL_UNINLINABLE(NODE) \
diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index 9743f3753d5..d3c24093b63 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -240,7 +240,13 @@ cp_convert_to_pointer (type, expr)
     {
       if (TYPE_PTRMEMFUNC_P (type))
 	return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0);
-      expr = build_int_2 (0, 0);
+
+      if (flag_new_abi && TYPE_PTRMEM_P (type))
+	/* Under the new ABI, a NULL pointer-to-member is represented
+	   by -1, not by zero.  */
+	expr = build_int_2 (-1, -1);
+      else
+	expr = build_int_2 (0, 0);
       TREE_TYPE (expr) = type;
       return expr;
     }
diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
index e97a65d55e8..230fa6a154b 100644
--- a/gcc/cp/expr.c
+++ b/gcc/cp/expr.c
@@ -65,11 +65,18 @@ cplus_expand_constant (cst)
 					  bit_position (member),
 					  bitsize_int (BITS_PER_UNIT)));
 
-	    /* We offset all pointer to data members by 1 so that we
-	       can distinguish between a null pointer to data member
-	       and the first data member of a structure.  */
-	    offset = size_binop (PLUS_EXPR, offset, size_one_node);
-	    cst = cp_convert (type, offset);
+	    if (flag_new_abi)
+	      /* Under the new ABI, we use -1 to represent the NULL
+		 pointer; non-NULL values simply contain the offset of
+		 the data member.  */
+	      ;
+	    else
+	      /* We offset all pointer to data members by 1 so that we
+		 can distinguish between a null pointer to data member
+		 and the first data member of a structure.  */
+	      offset = size_binop (PLUS_EXPR, offset, size_one_node);
+
+	    cst = fold (build1 (NOP_EXPR, type, offset));
 	  }
 	else
 	  {
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 960f46b0ac3..8994f604239 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1821,11 +1821,13 @@ resolve_offset_ref (exp)
       addr = convert_pointer_to (basetype, addr);
       member = cp_convert (ptrdiff_type_node, member);
 
-      /* Pointer to data members are offset by one, so that a null
-	 pointer with a real value of 0 is distinguishable from an
-	 offset of the first member of a structure.  */
-      member = build_binary_op (MINUS_EXPR, member,
-				cp_convert (ptrdiff_type_node, integer_one_node));
+      if (!flag_new_abi)
+	/* Pointer to data members are offset by one, so that a null
+	   pointer with a real value of 0 is distinguishable from an
+	   offset of the first member of a structure.  */
+	member = build_binary_op (MINUS_EXPR, member,
+				  cp_convert (ptrdiff_type_node, 
+					      integer_one_node));
 
       return build1 (INDIRECT_REF, type,
 		     build (PLUS_EXPR, build_pointer_type (type),
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index a92c1febfcf..43bd1bc4952 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -2858,7 +2858,7 @@ get_member_function_from_ptrfunc (instance_ptrptr, function)
 	{
 	  idx = build_binary_op (TRUNC_DIV_EXPR, 
 				 build1 (NOP_EXPR, vtable_index_type, e3),
-				 integer_two_node);
+				 TYPE_SIZE_UNIT (vtable_entry_type));
 	  e1 = build_binary_op (BIT_AND_EXPR,
 				build1 (NOP_EXPR, vtable_index_type, e3),
 				integer_one_node);
@@ -6332,11 +6332,12 @@ expand_ptrmemfunc_cst (cst, delta, idx, pfn, delta2)
 	}
       else
 	{
-	  /* Under the new ABI, we set PFN to twice the index, plus
-	     one.  */
+	  /* Under the new ABI, we set PFN to the vtable offset, plus
+	     one, at which the function can be found.  */
 	  *idx = NULL_TREE;
 	  *pfn = fold (build (MULT_EXPR, integer_type_node,
-			      DECL_VINDEX (fn), integer_two_node));
+			      DECL_VINDEX (fn), 
+			      TYPE_SIZE_UNIT (vtable_entry_type)));
 	  *pfn = fold (build (PLUS_EXPR, integer_type_node, *pfn,
 			      integer_one_node));
 	  *pfn = fold (build1 (NOP_EXPR, TYPE_PTRMEMFUNC_FN_TYPE (type),
diff --git a/gcc/testsuite/g++.old-deja/g++.abi/empty.C b/gcc/testsuite/g++.old-deja/g++.abi/empty.C
new file mode 100644
index 00000000000..b7a791f0a94
--- /dev/null
+++ b/gcc/testsuite/g++.old-deja/g++.abi/empty.C
@@ -0,0 +1,68 @@
+// Special g++ Options: -w
+// Origin: Mark Mitchell <mark@codesourcery.com>
+
+#if defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100
+
+struct S0
+{
+};
+
+struct S1 : public S0
+{
+};
+
+struct S2 : public S1
+{
+  char c;
+};
+
+// In S3, the S1 instance is allocated first at offset zero.  The S2
+// instance has to be allocated at a subsequent offset; it's first
+// part is also an S1.
+
+struct S3 : public S1, public S2
+{
+};
+
+struct S4 
+{
+  int i;
+};
+
+// In S4, in contrast to S3, S2 is allocated first, and S1 can be
+// allocated on top of S4.
+
+struct S5 : public S2, public S1, public S4
+{
+};
+
+// The T classes are by-hand layouts that should be equivalent to the
+// S classes.
+
+struct T3
+{
+  S1 s1;
+  S2 s2;
+};
+
+struct T5
+{
+  S2 s2;
+  S4 s4;
+};
+
+int main ()
+{
+  if (sizeof (S3) != sizeof (T3))
+    return 1;
+  else if (sizeof (S5) != sizeof (T5))
+    return 2;
+}
+
+#else /* !(defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100) */
+
+int main () 
+{
+}
+
+#endif /* !(defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100) */
diff --git a/gcc/testsuite/g++.old-deja/g++.abi/ptrmem.C b/gcc/testsuite/g++.old-deja/g++.abi/ptrmem.C
index 8dc3ee46a5c..975d9397ded 100644
--- a/gcc/testsuite/g++.old-deja/g++.abi/ptrmem.C
+++ b/gcc/testsuite/g++.old-deja/g++.abi/ptrmem.C
@@ -82,16 +82,16 @@ main ()
   if (xp->adj != delta)
     return 8;
 
-  // For a virtual function, we should see twice the vtable index,
-  // plus one.  `T::h' is in the third slot: there's the RTTI entry,
-  // then the two virtual functions.
+  // For a virtual function, we should see the vtable offset, plus
+  // one.  `T::h' is in the second slot: the vtable pointer points to
+  // the first virtual function.
   y = &T::h;
-  if ((ptrdiff_t) yp->ptr != 7)
+  if ((ptrdiff_t) yp->ptr != sizeof (void *) + 1)
     return 9;
   if (yp->adj != 0)
     return 10;
   x = (sp) y;
-  if ((ptrdiff_t) xp->ptr != 7)
+  if ((ptrdiff_t) xp->ptr != sizeof (void *) + 1)
     return 11;
   if (xp->adj != delta)
     return 12;
@@ -103,9 +103,14 @@ main ()
   if (__alignof__ (sdp) != __alignof__ (ptrdiff_t))
     return 14;
 
+  // The value of a pointer-to-data member should be the offset from
+  // the start of the structure.
   sdp z = &S::j;
-  if ((char *) &s.j - (char *) &s != *((ptrdiff_t *) &z) - 1)
+  if ((char *) &s.j - (char *) &s != *((ptrdiff_t *) &z))
     return 15;
+  z = 0;
+  if (*((ptrdiff_t *) &z) != -1)
+    return 16;
 }
 
 #else /* !(defined (__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100) */