Make tag, resource and object constructors take their arguments by copy

Doing something like some([1, 2, 3]) will now no longer create a temporary
copy of the vector. It will also be easier for the kind checker to see that
putting a resource into a data-structure constructor is safe.

Author: marijnh

src/comp/middle/trans.rs

@@ -3587,8 +3587,8 @@ fn trans_bind_1(cx: @block_ctxt, outgoing_fty: ty::t,
     };
 
     // Actually construct the closure
-    let closure = build_environment
-        (bcx, lltydescs, env_vals + vec::map(env_expr, bound), true);
+    let closure = build_environment(bcx, lltydescs, env_vals +
+                                    vec::map({|x| env_expr(x)}, bound), true);
     bcx = closure.bcx;
 
     // Make thunk
@@ -5163,12 +5163,9 @@ fn trans_res_ctor(cx: @local_ctxt, sp: span, dtor: ast::_fn,
     let lltop = bcx.llbb;
     let arg_t = arg_tys_of_fn(ccx, ctor_id)[0].ty;
     let tup_t = ty::mk_tup(ccx.tcx, [ty::mk_int(ccx.tcx), arg_t]);
-    let arg;
-    alt fcx.llargs.find(dtor.decl.inputs[0].id) {
-      some(local_mem(x)) { arg = load_if_immediate(bcx, x, arg_t); }
-      some(local_imm(x)) { arg = x; }
-      _ { ccx.sess.span_fatal(sp, "unbound dtor decl in trans_res_ctor"); }
-    }
+    let arg = alt fcx.llargs.find(dtor.decl.inputs[0].id) {
+      some(local_mem(x)) { x }
+    };
     let llretptr = fcx.llretptr;
     if ty::type_has_dynamic_size(ccx.tcx, ret_t) {
         let llret_t = T_ptr(T_struct([ccx.int_type, llvm::LLVMTypeOf(arg)]));
@@ -5177,9 +5174,8 @@ fn trans_res_ctor(cx: @local_ctxt, sp: span, dtor: ast::_fn,
 
     // FIXME: silly checks
     check type_is_tup_like(bcx, tup_t);
-    let dst = GEP_tup_like(bcx, tup_t, llretptr, [0, 1]);
-    bcx = dst.bcx;
-    bcx = copy_val(bcx, INIT, dst.val, arg, arg_t);
+    let {bcx, val: dst} = GEP_tup_like(bcx, tup_t, llretptr, [0, 1]);
+    bcx = memmove_ty(bcx, dst, arg, arg_t);
     check type_is_tup_like(bcx, tup_t);
     let flag = GEP_tup_like(bcx, tup_t, llretptr, [0, 0]);
     bcx = flag.bcx;
@@ -5206,7 +5202,7 @@ fn trans_tag_variant(cx: @local_ctxt, tag_id: ast::node_id,
     let i = 0u;
     for varg: ast::variant_arg in variant.node.args {
         fn_args +=
-            [{mode: ast::by_ref,
+            [{mode: ast::by_copy,
               ty: varg.ty,
               ident: "arg" + uint::to_str(i, 10u),
               id: varg.id}];
@@ -5261,11 +5257,9 @@ fn trans_tag_variant(cx: @local_ctxt, tag_id: ast::node_id,
         if ty::type_contains_params(bcx_tcx(bcx), arg_ty) {
             lldestptr = PointerCast(bcx, lldestptr, val_ty(llarg));
         }
-        llarg = load_if_immediate(bcx, llarg, arg_ty);
-        bcx = copy_val(bcx, INIT, lldestptr, llarg, arg_ty);
+        bcx = memmove_ty(bcx, lldestptr, llarg, arg_ty);
         i += 1u;
     }
-    bcx = trans_block_cleanups(bcx, find_scope_cx(bcx));
     build_return(bcx);
     finish_fn(fcx, lltop);
 }

src/comp/middle/trans_objects.rs

@@ -41,7 +41,7 @@ fn trans_obj(cx: @local_ctxt, sp: span, ob: ast::_obj, ctor_id: ast::node_id,
     // we're creating.
     let fn_args: [ast::arg] = [];
     for f: ast::obj_field in ob.fields {
-        fn_args += [{mode: ast::by_ref, ty: f.ty, ident: f.ident,
+        fn_args += [{mode: ast::by_copy, ty: f.ty, ident: f.ident,
                      id: f.id}];
     }
     let fcx = new_fn_ctxt(cx, sp, llctor_decl);
@@ -174,28 +174,19 @@ fn trans_obj(cx: @local_ctxt, sp: span, ob: ast::_obj, ctor_id: ast::node_id,
         let body_fields =
             GEP_tup_like(bcx, body_ty, body, [0, abi::obj_body_elt_fields]);
         bcx = body_fields.bcx;
+        // TODO: can we just get fields_ty out of body_ty instead?
+        let fields_ty = ty::mk_tup(ccx.tcx, obj_fields);
         i = 0;
         for f: ast::obj_field in ob.fields {
             alt bcx.fcx.llargs.find(f.id) {
-              some(arg1) {
-                let arg = alt arg1 {
-                  local_mem(v) { load_if_immediate(bcx, v, arg_tys[i].ty) }
-                  local_imm(v) { v }
-                };
-                // TODO: can we just get fields_ty out of body_ty instead?
-                let fields_ty: ty::t = ty::mk_tup(ccx.tcx, obj_fields);
+              some(local_mem(arg)) {
                 // Silly check
                 check type_is_tup_like(bcx, fields_ty);
                 let field =
                     GEP_tup_like(bcx, fields_ty, body_fields.val, [0, i]);
-                bcx = field.bcx;
-                bcx = copy_val(bcx, INIT, field.val, arg, arg_tys[i].ty);
+                bcx = memmove_ty(field.bcx, field.val, arg, arg_tys[i].ty);
                 i += 1;
               }
-              none. {
-                bcx_ccx(bcx).sess.span_fatal(f.ty.span,
-                                             "internal error in trans_obj");
-              }
             }
         }
 

src/comp/middle/ty.rs

@@ -84,7 +84,6 @@ export mk_type;
 export mk_uint;
 export mk_uniq;
 export mk_var;
-export mk_iter_body_fn;
 export mode;
 export mt;
 export node_type_table;
@@ -587,11 +586,6 @@ fn mk_type(_cx: ctxt) -> t { ret idx_type; }
 
 fn mk_native(cx: ctxt, did: def_id) -> t { ret gen_ty(cx, ty_native(did)); }
 
-fn mk_iter_body_fn(cx: ctxt, output: t) -> t {
-    ret mk_fn(cx, ast::proto_block, [{mode: ast::by_ref, ty: output}],
-              ty::mk_nil(cx), ast::return_val, []);
-}
-
 // Returns the one-level-deep type structure of the given type.
 pure fn struct(cx: ctxt, typ: t) -> sty { interner::get(*cx.ts, typ).struct }
 

src/comp/middle/typeck.rs

@@ -597,7 +597,7 @@ mod collect {
         for f: ast::obj_field in ob.fields {
             let g = bind getter(cx, _);
             let t_field = ast_ty_to_ty(cx.tcx, g, f.ty);
-            t_inputs += [{mode: ast::by_ref, ty: t_field}];
+            t_inputs += [{mode: ast::by_copy, ty: t_field}];
         }
 
         let t_fn =
@@ -646,8 +646,7 @@ mod collect {
             let t_arg = ty_of_arg(cx, f.decl.inputs[0]);
             let t_res =
                 {kinds: ty_param_kinds(tps),
-                 ty:
-                     ty::mk_res(cx.tcx, local_def(it.id), t_arg.ty,
+                 ty: ty::mk_res(cx.tcx, local_def(it.id), t_arg.ty,
                                 mk_ty_params(cx, tps))};
             cx.tcx.tcache.insert(local_def(it.id), t_res);
             ret t_res;
@@ -708,7 +707,7 @@ mod collect {
                 let args: [arg] = [];
                 for va: ast::variant_arg in variant.node.args {
                     let arg_ty = ast_ty_to_ty(cx.tcx, f, va.ty);
-                    args += [{mode: ast::by_ref, ty: arg_ty}];
+                    args += [{mode: ast::by_copy, ty: arg_ty}];
                 }
                 let tag_t = ty::mk_tag(cx.tcx, tag_id, ty_param_tys);
                 // FIXME: this will be different for constrained types
@@ -785,7 +784,7 @@ mod collect {
                            mk_ty_params(cx, tps));
             let t_ctor =
                 ty::mk_fn(cx.tcx, ast::proto_shared(ast::sugar_normal),
-                          [t_arg], t_res,
+                          [{mode: ast::by_copy with t_arg}], t_res,
                           ast::return_val, []);
             let t_dtor =
                 ty::mk_fn(cx.tcx, ast::proto_shared(ast::sugar_normal),