Comments and cleanup.

This commit is contained in:
Lindsey Kuper 2011-06-03 17:09:50 -07:00
parent cb4c969ba6
commit dcf7fbf833
1 changed files with 65 additions and 32 deletions

View File

@ -160,8 +160,8 @@ state type fn_ctxt = rec(
// The three implicit arguments that arrive in the function we're
// creating. For instance, foo(int, int) is really foo(ret*, task*, env*,
// int, int). These are also available via llvm::LLVMGetParam(llfn, uint)
// where uint = 2, 0, 1 respectively, but we unpack them here for
// convenience.
// where uint = 1, 2, 0 respectively, but we unpack them into these fields
// for convenience.
ValueRef lltaskptr,
ValueRef llenv,
ValueRef llretptr,
@ -7000,6 +7000,7 @@ fn trans_fn(@local_ctxt cx, &span sp, &ast::_fn f, ast::def_id fid,
&vec[ast::ty_param] ty_params, &ast::ann ann) {
auto llfndecl = cx.ccx.item_ids.get(fid);
// Set up arguments to the function.
auto fcx = new_fn_ctxt(cx, sp, llfndecl);
create_llargs_for_fn_args(fcx, f.proto,
ty_self, ret_ty_of_fn(cx.ccx, ann),
@ -7018,9 +7019,10 @@ fn trans_fn(@local_ctxt cx, &span sp, &ast::_fn f, ast::def_id fid,
auto arg_tys = arg_tys_of_fn(fcx.lcx.ccx, ann);
copy_args_to_allocas(fcx, f.decl.inputs, arg_tys);
// Create the first basic block in the function and keep a handle on it to
// pass to finish_fn later.
auto bcx = new_top_block_ctxt(fcx);
add_cleanups_for_args(bcx, f.decl.inputs, arg_tys);
auto lltop = bcx.llbb;
auto block_ty = node_ann_type(cx.ccx, f.body.node.a);
@ -7041,9 +7043,12 @@ fn trans_fn(@local_ctxt cx, &span sp, &ast::_fn f, ast::def_id fid,
res.bcx.build.RetVoid();
}
// Insert the mandatory first few basic blocks before lltop.
finish_fn(fcx, lltop);
}
// Create a vtable for an object being translated. Returns a pointer into
// read-only memory.
fn create_vtbl(@local_ctxt cx,
TypeRef llself_ty,
ty::t self_ty,
@ -7136,13 +7141,15 @@ fn trans_obj(@local_ctxt cx, &span sp, &ast::_obj ob, ast::def_id oid,
// starting with an ast::_obj rather than an ast::_fn, we have some setup
// work to do.
// Translate obj ctor args to function arguments.
// The fields of our object will become the arguments to the function
// we're creating.
let vec[ast::arg] fn_args = [];
for (ast::obj_field f in ob.fields) {
fn_args += [rec(mode=ast::alias, ty=f.ty, ident=f.ident, id=f.id)];
}
auto fcx = new_fn_ctxt(cx, sp, llctor_decl);
// Both regular arguments and type parameters are handled here.
create_llargs_for_fn_args(fcx, ast::proto_fn,
none[ty_self_pair],
ret_ty_of_fn(ccx, ann),
@ -7151,78 +7158,103 @@ fn trans_obj(@local_ctxt cx, &span sp, &ast::_obj ob, ast::def_id oid,
let vec[ty::arg] arg_tys = arg_tys_of_fn(ccx, ann);
copy_args_to_allocas(fcx, fn_args, arg_tys);
// Make the first block context in the function and keep a handle on it
// Create the first block context in the function and keep a handle on it
// to pass to finish_fn later.
auto bcx = new_top_block_ctxt(fcx);
auto lltop = bcx.llbb;
// Pick up the type of this object by looking at our own output type, that
// is, the output type of the object constructor we're building.
auto self_ty = ret_ty_of_fn(ccx, ann);
auto llself_ty = type_of(ccx, sp, self_ty);
// Set up the two-word pair that we're going to return from the object
// constructor we're building. The two elements of this pair will be a
// vtable pointer and a body pointer. (llretptr already points to the
// place where this two-word pair should go; it was pre-allocated by the
// caller of the function.)
auto pair = bcx.fcx.llretptr;
auto vtbl = create_vtbl(cx, llself_ty, self_ty, ob, ty_params);
// Grab onto the first and second elements of the pair.
// abi::obj_field_vtbl and abi::obj_field_box simply specify words 0 and 1
// of 'pair'.
auto pair_vtbl = bcx.build.GEP(pair,
[C_int(0),
C_int(abi::obj_field_vtbl)]);
C_int(abi::obj_field_vtbl)]);
auto pair_box = bcx.build.GEP(pair,
[C_int(0),
C_int(abi::obj_field_box)]);
C_int(abi::obj_field_box)]);
// Make a vtable for this object: a static array of pointers to functions.
// It will be located in the read-only memory of the executable we're
// creating and will contain ValueRefs for all of this object's methods.
// create_vtbl returns a pointer to the vtable, which we store.
auto vtbl = create_vtbl(cx, llself_ty, self_ty, ob, ty_params);
bcx.build.Store(vtbl, pair_vtbl);
let TypeRef llbox_ty = T_opaque_obj_ptr(ccx.tn);
// Next we have to take care of the other half of the pair we're
// returning: a boxed (reference-counted) tuple containing a tydesc,
// typarams, and fields.
// FIXME we should probably also allocate a box for empty objs that have a
// dtor, since otherwise they are never dropped, and the dtor never runs
// FIXME: What about with_obj? Do we have to think about it here?
// (Pertains to issue #417.)
let TypeRef llbox_ty = T_opaque_obj_ptr(ccx.tn);
// FIXME: we should probably also allocate a box for empty objs that have
// a dtor, since otherwise they are never dropped, and the dtor never
// runs.
if (vec::len[ast::ty_param](ty_params) == 0u &&
vec::len[ty::arg](arg_tys) == 0u) {
// If the object we're translating has no fields or type parameters,
// there's not much to do.
// Store null into pair, if no args or typarams.
bcx.build.Store(C_null(llbox_ty), pair_box);
} else {
// Malloc a box for the body and copy args in.
// Otherwise, we have to synthesize a big structural type for the
// object body.
let vec[ty::t] obj_fields = [];
for (ty::arg a in arg_tys) {
vec::push[ty::t](obj_fields, a.ty);
}
// Synthesize an obj body type.
// Tuple type for fields: [field, ...]
let ty::t fields_ty = ty::mk_imm_tup(ccx.tcx, obj_fields);
// Tuple type for typarams: [typaram, ...]
auto tydesc_ty = ty::mk_type(ccx.tcx);
let vec[ty::t] tps = [];
for (ast::ty_param tp in ty_params) {
vec::push[ty::t](tps, tydesc_ty);
}
// typarams_ty = [typaram_ty, ...]
let ty::t typarams_ty = ty::mk_imm_tup(ccx.tcx, tps);
// fields_ty = [field_ty, ...]
let ty::t fields_ty = ty::mk_imm_tup(ccx.tcx, obj_fields);
// body_ty = [tydesc_ty, [typaram_ty, ...], [field_ty, ...]]
// Tuple type for body: [tydesc_ty, [typaram, ...], [field, ...]]
let ty::t body_ty = ty::mk_imm_tup(ccx.tcx,
[tydesc_ty,
typarams_ty,
fields_ty]);
// boxed_body_ty = [[tydesc_ty, [typaram_ty, ...], [field_ty, ...]]]
let ty::t boxed_body_ty = ty::mk_imm_box(ccx.tcx, body_ty);
// Malloc a box for the body.
// Hand this thing we've constructed off to trans_malloc_boxed, which
// makes space for the refcount.
auto box = trans_malloc_boxed(bcx, body_ty);
bcx = box.bcx;
auto rc = GEP_tup_like(bcx, boxed_body_ty, box.val,
[0, abi::box_rc_field_refcnt]);
bcx = rc.bcx;
// We've now created a structure that looks like:
// [refcount, [tydesc_ty, [typaram_ty, ...], [field_ty, ...]]]
// And mk_imm_box throws a refcount into the type we're synthesizing:
// [rc, [tydesc_ty, [typaram, ...], [field, ...]]]
let ty::t boxed_body_ty = ty::mk_imm_box(ccx.tcx, body_ty);
auto rc = GEP_tup_like(bcx, boxed_body_ty, box.val,
[0,
abi::box_rc_field_refcnt]);
bcx = rc.bcx;
auto body = GEP_tup_like(bcx, boxed_body_ty, box.val,
[0, abi::box_rc_field_body]);
bcx = body.bcx;
bcx.build.Store(C_int(1), rc.val);
// Put together a tydesc for the body, so that the object can later be
@ -7285,6 +7317,7 @@ fn trans_obj(@local_ctxt cx, &span sp, &ast::_obj ob, ast::def_id oid,
}
bcx.build.RetVoid();
// Insert the mandatory first few basic blocks before lltop.
finish_fn(fcx, lltop);
}