Minutes, February 8, 2000
991026.3 Duplicate Dwarf data deletion
The proposal has evolved since it was originally raised. The current
idea is to add an extension to TAG_compilation_unit which will refer
to another TAG_compilation_unit, which contains information not provided
in the current comp unit. Some concern was expressed that this did not
address all of the duplicate data issues raised in the original proposal.
Jason Merrill will rewrite the proposal. He will also provide a description
of the COMDAT proposal, which can be used to eliminate duplicate data.
991108.2 Virtual functions extensions
The existing standard does not support using multiple vtables to reference
multiple base classes. One suggestion was to use TAG_member to identify the
vtable. Mike Eager suggested that it would be better to create a new tag,
rather than overload TAG_member (5.5.4 describes TAG_member as describing
data members). Felix Burton suggested that a generalized call operation in
the location expression could be used to compute vtable addresses, as well
as have other uses. He will draft a proposal to add OP_call. The Dwarf 2
spec should describe the state of the stack when a location expression is
evaluated. In many cases, the address of the object must be on the stack when
the location expression is evaluated. Jason will rewrite the proposal with
only DW_AT_vptr_* specifications.
000131.1 Prolog identification
A suggestion was made to use the line table to identify the line number where
the prolog ends. This may be not provide adequate precision, since multiple C
statements may start on the same line. After discussion, Dave Anderson said
that he would propose extensions to the line number state machine which would
identify the end of multiple prologs and the start of multiple epilogs.