ffi: move run-time state out of txr_ffi_type.

The txr_ffi_type has the buf member, which is manipulated when
FFI calls are being dispatched.

That is wrongly non-reentrant; it will interfere with the same
type structure being used recursively.  The objects describing
FFI types must be treated as immutable with respect to dynamic
FFI processing.

The approach here is is to move these buf pointers into a
a run-time vector ("rtvec"). The types whose handling requires
the temporary buf pointer are assigned a position in that
vector (the "rtidx"). These positions are assigned to the
nodes of a type by a tree walking step after compilation.

When performing a FFI call, we allocate space for the rtvec
for each argument type. This is vector is passed down into the
data transfer calls, and is used wherever needed, using a
type's rtidx to find its buffer pointer location.

* ffi.c (struct txr_ffi_type): function functoin poiner member,
walk. The put and in functions get a new argument: the rtvec.
New members rtidx and rtsize. The buf member is removed.
(ffi_builtin_type_destruct_destroy_op): Static function
removed. There is no need to clean any run-time buffer
from a type, since types are no longer associated with any
such thing. And that leaves the function just freeing
the obj->co.handle which is already done by
cobj_destroy_free_op.
(ffi_type_struct_destroy_op, ffi_type_struct_destroy_op):
Remove the call to the in virtual function for the same
reason.
(ffi_type_builtin_ops, ffi_type_ptr_ops): Replace removed
ffi_builtin_type_struct_destroy_op with cobj_destroy_free_op.
(ffi_void_put, ffi_i8_put, ffi_u8_put, ffi_i16_put,
ffi_u16_put, ffi_i32_put, ffi_u32_put, ffi_i64_put,
ffi_u64_put, ffi_char_put, ffi_uchar_put, ffi_short_put,
ffi_ushort_put, ffi_int_put, ffi_uint_put, ffi_long_put,
ffi_ulong_put, ffi_float_put, ffi_double_put, ffi_cptr_put):
Conform to new put interface with the rtvec argument.
It is ignored in all these functions.
(ffi_freeing_in, ffi_str_put, ffi_wstr_put, ffi_buf_put,
ffi_ptr_in_in, ffi_ptr_in_put, ffi_ptr_out_in,
ffi_ptr_out_put, ffi_ptr_in_out_put, ffi_struct_in,
ffi_struct_put, ffi_array_in, ffi_array_put)
Conform to new function interface with the rtvec and use it
together with the rtidx from the type to store and retrieve
the buf, if necessary.
(ffi_ptr_walk, ffi_struct_walk): New functions.
(make_ffi_type_builtin): Parameter declaration updated due
to changes in put and in function pointer types.
(make_ffi_type_pointer): Configure pointer's rtsize to 1
since pointers manage temporary buffers, and give it the
ffi_ptr_walk function, since it has a subordinate type which
it must visit.
(make_ffi_type_struct): Calculate the size of the rtvec
which a struct's members need. Use the nonzero value of this
as the indication that the structure need's an in function,
thus eliminating the loop flag being used for this purpose.
Install the ffi_struct_walk function for walk.
(make_ffi_type_array): Similar changes as in
make_ffi_type_struct. Calculate rtsize from element rtsize
times number of elements. If that is nonzero wire in
ffi_array_in. Also wire in ffi_struct_walk.
(ffi_type_walk): New static function.

(assign_rtindices_visit, ffi_type_assign_rtindices): New
functions.
(ffi_type_compile): Set the rtsize for the str type to 1,
because it manages a temporary buffer across the FFI call,
and thus needs a slot in the rtvec.
(ffi_type_compile_toplevel): New function.
(ffi_call_wrap): Allocate vector of rtvectors based on total
number of arguments. For each argument allocate an rtvector in
this vector, if necessary and pass down to the put calls. Then
pass to the in calls after the FFI call returns. Thus the
framework has the proper environment where to store all the
temporary buffer pointers that need to be communicated from
the pre-call data transfer pass to the subsequent cleanup.
(ffi_init): Register the ffi_type_compile_toplevel function
as the ffi-type-compile intrinsic, rather than the
ffi_type_compile function. Application space probably doesn't
need to have exposure to compiler output which doesn't have
the correct rtidx values, and there is a risk it could be
accidentally used.

0 files changed, 0 insertions, 0 deletions