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

From-SVN: r46218

1 files changed, 12 insertions, 0 deletions

diff --git a/gcc/doc/c-tree.texi b/gcc/doc/c-tree.texi
index 85962c7..9eccc0d 100644
--- a/gcc/doc/c-tree.texi
+++ b/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