Re: [PATCH v2 6/8] Create xml from target descriptions

Yao Qi
2018-01-25T15:45:05Z

Philipp Rudo <prudo@linux.vnet.ibm.com> writes:

> Same for tdesc_type::make_gdb_type (patch #5). But here i would prefer to not
> even declare the method for GDBserver, i.e.
>
> struct tdesc_type
> {
>
> [...]
>
> #ifndef GDBSERVER
> virtual type *make_gdb_type (struct gdbarch *gdbarch) const = 0;
> #endif
> };
>
> The problem i see with implementing stubs calling error is that you cannot find
> out you made a mistake until you call the function during run-time. This gives
> room to nasty bugs which could easily be prevented when there is a compile bug.

make_gdb_type and gdbarch shouldn't be put into arch/tdesc.h at all, if
possible. You can create an sub-class of tdesc_element_visitor in gdb
side, and create the gdb type by visiting these elements, like this,

class gdb_type_creator : public tdesc_element_visitor
{
public:
gdb_type_createor (struct gdbarch *gdbarch)
: m_gdbarch (gdbarch)
{}

void visit (const tdesc_type_builtin *e) override
{
switch (e->kind)
{
case TDESC_TYPE_BOOL:
m_type = builtin_type (m_gdbarch)->builtin_bool;
break;
....
};
}

void visit (const tdesc_type_vector *e) override
{
// do what tdesc_type_vector::make_gdb_type does.
}

void visit (const tdesc_type_with_fields *e) override
{
// likewise.
}

private:
// input
struct * const m_gdbarch;
// output
type *m_type;
};

gdb_type_creator gdb_type (gdbarch);

tdesc_type->accept (gdb_type);

gdb_type.m_type is the type we need.

--
Yao (齐尧)