Re: cleanup vtable gc

[Richard Henderson <rth at redhat dot com>]

> This should be documented in c-tree.texi.

Ah yes.  I forgot we had tree docs outside the headers.


r~


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

Index: c-tree.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/c-tree.texi,v
retrieving revision 1.20
diff -c -p -d -r1.20 c-tree.texi
*** c-tree.texi	2001/10/09 23:11:55	1.20
--- c-tree.texi	2001/10/12 00:36:36
*************** This macro returns the attributes on the
*** 1741,1746 ****
--- 1741,1747 ----
  @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
*************** is taken, and this value replaces the fi
*** 2252,2256 ****
--- 2253,2268 ----
  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