* doc/c-tree.texi (Expression trees): Add VTABLE_REF.

From-SVN: r46218

gcc/ChangeLog

 2001-10-11  Richard Henderson  <rth@redhat.com>
 
+	* doc/c-tree.texi (Expression trees): Add VTABLE_REF.
+
+2001-10-11  Richard Henderson  <rth@redhat.com>
+
 	* dwarf2out.c (add_const_value_attribute): If long < HOST_WIDE_INT,
 	fall back to add_AT_long_long for large CONST_INT.
 

gcc/doc/c-tree.texi

@@ -1741,6 +1741,7 @@ This macro returns the attributes on the type @var{type}.
 @tindex EXIT_EXPR
 @tindex CLEANUP_POINT_EXPR
 @tindex ARRAY_REF
+@tindex VTABLE_REF
 
 The internal representation for expressions is for the most part quite
 straightforward.  However, there are a few facts that one must bear in
@@ -2253,4 +2254,15 @@ list.  In this case, the value of the expression is the @code{VAR_DECL}
 given by the third operand to the @code{AGGR_INIT_EXPR}; constructors do
 not return a value.
 
+@item VTABLE_REF
+A @code{VTABLE_REF} indicates that the interior expression computes
+a value that is a vtable entry.  It is used with @option{-fvtable-gc}
+to track the reference through to front end to the middle end, at
+which point we transform this to a @code{REG_VTABLE_REF} note, which
+survives the balance of code generation.
+
+The first operand is the expression that computes the vtable reference.
+The second operand is the @code{VAR_DECL} of the vtable.  The third
+operand is an @code{INTEGER_CST} of the byte offset into the vtable.
+
 @end table