Use dwarf assembler in gdb.dwarf2/implptr-64bit.exp
This patch adds a DW_OP_implicit_value in dwarf assembler, and uses
dwarf assembler in implptr-64bit.exp. Using dwarf assembler in
implptr-64bit.exp exposes some limitations in dwarf assembler,
- some variables are not evaluated in the caller's context, so we
can not pass variable to assembler, like this
Dwarf::assemble $asm_file {
cu {
version $dwarf_version
addr_size $addr_size
is_64 $is_64
} {
}
this limitation is fixed by adding "uplevel" and "subst".
- dwarf assembler doesn't emit DW_FORM_ref_addr for label referencing.
this limitation is fixed by adding a new character "%",
{ type %$int_label }
this means we want to emit DW_FORM_ref_addr for label referencing.
- we can't set the form of label referencing offset in dwarf assembler.
Nowadays, dwarf assembler guesses the form of labels, which is
DW_FORM_ref4. However, in implptr-64bit.exp, both DW_FORM_ref4
and DW_FORM_ref8 is used (see REF_ADDR in implptr-64bit.S). This
patch adds the flexibility of setting the form of label reference.
Both of them below are valid,