| /*! |
| * # Categorization |
| * |
| * The job of the categorization module is to analyze an expression to |
| * determine what kind of memory is used in evaluating it (for example, |
| * where dereferences occur and what kind of pointer is dereferenced; |
| * whether the memory is mutable; etc) |
| * |
| * Categorization effectively transforms all of our expressions into |
| * expressions of the following forms (the actual enum has many more |
| * possibilities, naturally, but they are all variants of these base |
| * forms): |
| * |
| * E = rvalue // some computed rvalue |
| * | x // address of a local variable, arg, or upvar |
| * | *E // deref of a ptr |
| * | E.comp // access to an interior component |
| * |
| * Imagine a routine ToAddr(Expr) that evaluates an expression and returns an |
| * address where the result is to be found. If Expr is an lvalue, then this |
| * is the address of the lvalue. If Expr is an rvalue, this is the address of |
| * some temporary spot in memory where the result is stored. |
| * |
| * Now, cat_expr() classies the expression Expr and the address A=ToAddr(Expr) |
| * as follows: |
| * |
| * - cat: what kind of expression was this? This is a subset of the |
| * full expression forms which only includes those that we care about |
| * for the purpose of the analysis. |
| * - mutbl: mutability of the address A |
| * - ty: the type of data found at the address A |
| * |
| * The resulting categorization tree differs somewhat from the expressions |
| * themselves. For example, auto-derefs are explicit. Also, an index a[b] is |
| * decomposed into two operations: a derefence to reach the array data and |
| * then an index to jump forward to the relevant item. |
| */ |
| |
| use syntax::ast; |
| use syntax::ast::{m_imm, m_const, m_mutbl}; |
| use syntax::codemap::span; |
| use syntax::print::pprust; |
| use util::ppaux::{ty_to_str, region_to_str}; |
| use util::common::indenter; |
| |
| enum categorization { |
| cat_rvalue, // result of eval'ing some misc expr |
| cat_special(special_kind), // |
| cat_local(ast::node_id), // local variable |
| cat_binding(ast::node_id), // pattern binding |
| cat_arg(ast::node_id), // formal argument |
| cat_stack_upvar(cmt), // upvar in stack closure |
| cat_deref(cmt, uint, ptr_kind), // deref of a ptr |
| cat_comp(cmt, comp_kind), // adjust to locate an internal component |
| cat_discr(cmt, ast::node_id), // match discriminant (see preserve()) |
| } |
| |
| impl categorization : cmp::Eq { |
| pure fn eq(other: &categorization) -> bool { |
| match self { |
| cat_rvalue => { |
| match (*other) { |
| cat_rvalue => true, |
| _ => false |
| } |
| } |
| cat_special(e0a) => { |
| match (*other) { |
| cat_special(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| cat_local(e0a) => { |
| match (*other) { |
| cat_local(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| cat_binding(e0a) => { |
| match (*other) { |
| cat_binding(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| cat_arg(e0a) => { |
| match (*other) { |
| cat_arg(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| cat_stack_upvar(e0a) => { |
| match (*other) { |
| cat_stack_upvar(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| cat_deref(e0a, e1a, e2a) => { |
| match (*other) { |
| cat_deref(e0b, e1b, e2b) => |
| e0a == e0b && e1a == e1b && e2a == e2b, |
| _ => false |
| } |
| } |
| cat_comp(e0a, e1a) => { |
| match (*other) { |
| cat_comp(e0b, e1b) => e0a == e0b && e1a == e1b, |
| _ => false |
| } |
| } |
| cat_discr(e0a, e1a) => { |
| match (*other) { |
| cat_discr(e0b, e1b) => e0a == e0b && e1a == e1b, |
| _ => false |
| } |
| } |
| } |
| } |
| pure fn ne(other: &categorization) -> bool { !self.eq(other) } |
| } |
| |
| // different kinds of pointers: |
| enum ptr_kind { |
| uniq_ptr, |
| gc_ptr, |
| region_ptr(ty::region), |
| unsafe_ptr |
| } |
| |
| impl ptr_kind : cmp::Eq { |
| pure fn eq(other: &ptr_kind) -> bool { |
| match self { |
| uniq_ptr => { |
| match (*other) { |
| uniq_ptr => true, |
| _ => false |
| } |
| } |
| gc_ptr => { |
| match (*other) { |
| gc_ptr => true, |
| _ => false |
| } |
| } |
| region_ptr(e0a) => { |
| match (*other) { |
| region_ptr(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| unsafe_ptr => { |
| match (*other) { |
| unsafe_ptr => true, |
| _ => false |
| } |
| } |
| } |
| } |
| pure fn ne(other: &ptr_kind) -> bool { !self.eq(other) } |
| } |
| |
| // I am coining the term "components" to mean "pieces of a data |
| // structure accessible without a dereference": |
| enum comp_kind { |
| comp_tuple, // elt in a tuple |
| comp_variant(ast::def_id), // internals to a variant of given enum |
| comp_field(ast::ident, // name of field |
| ast::mutability), // declared mutability of field |
| comp_index(ty::t, // type of vec/str/etc being deref'd |
| ast::mutability) // mutability of vec content |
| } |
| |
| impl comp_kind : cmp::Eq { |
| pure fn eq(other: &comp_kind) -> bool { |
| match self { |
| comp_tuple => { |
| match (*other) { |
| comp_tuple => true, |
| _ => false |
| } |
| } |
| comp_variant(e0a) => { |
| match (*other) { |
| comp_variant(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| comp_field(e0a, e1a) => { |
| match (*other) { |
| comp_field(e0b, e1b) => e0a == e0b && e1a == e1b, |
| _ => false |
| } |
| } |
| comp_index(e0a, e1a) => { |
| match (*other) { |
| comp_index(e0b, e1b) => e0a == e0b && e1a == e1b, |
| _ => false |
| } |
| } |
| } |
| } |
| pure fn ne(other: &comp_kind) -> bool { !self.eq(other) } |
| } |
| |
| // different kinds of expressions we might evaluate |
| enum special_kind { |
| sk_method, |
| sk_static_item, |
| sk_self, |
| sk_heap_upvar |
| } |
| |
| impl special_kind : cmp::Eq { |
| pure fn eq(other: &special_kind) -> bool { |
| (self as uint) == ((*other) as uint) |
| } |
| pure fn ne(other: &special_kind) -> bool { !self.eq(other) } |
| } |
| |
| // a complete categorization of a value indicating where it originated |
| // and how it is located, as well as the mutability of the memory in |
| // which the value is stored. |
| type cmt_ = {id: ast::node_id, // id of expr/pat producing this value |
| span: span, // span of same expr/pat |
| cat: categorization, // categorization of expr |
| lp: Option<@loan_path>, // loan path for expr, if any |
| mutbl: ast::mutability, // mutability of expr as lvalue |
| ty: ty::t}; // type of the expr |
| |
| type cmt = @cmt_; |
| |
| impl cmt_ : cmp::Eq { |
| pure fn eq(other: &cmt_) -> bool { |
| self.id == (*other).id && |
| self.span == (*other).span && |
| self.cat == (*other).cat && |
| self.lp == (*other).lp && |
| self.mutbl == (*other).mutbl && |
| self.ty == (*other).ty |
| } |
| pure fn ne(other: &cmt_) -> bool { !self.eq(other) } |
| } |
| |
| // a loan path is like a category, but it exists only when the data is |
| // interior to the stack frame. loan paths are used as the key to a |
| // map indicating what is borrowed at any point in time. |
| enum loan_path { |
| lp_local(ast::node_id), |
| lp_arg(ast::node_id), |
| lp_deref(@loan_path, ptr_kind), |
| lp_comp(@loan_path, comp_kind) |
| } |
| |
| impl loan_path : cmp::Eq { |
| pure fn eq(other: &loan_path) -> bool { |
| match self { |
| lp_local(e0a) => { |
| match (*other) { |
| lp_local(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| lp_arg(e0a) => { |
| match (*other) { |
| lp_arg(e0b) => e0a == e0b, |
| _ => false |
| } |
| } |
| lp_deref(e0a, e1a) => { |
| match (*other) { |
| lp_deref(e0b, e1b) => e0a == e0b && e1a == e1b, |
| _ => false |
| } |
| } |
| lp_comp(e0a, e1a) => { |
| match (*other) { |
| lp_comp(e0b, e1b) => e0a == e0b && e1a == e1b, |
| _ => false |
| } |
| } |
| } |
| } |
| pure fn ne(other: &loan_path) -> bool { !self.eq(other) } |
| } |
| |
| // We pun on *T to mean both actual deref of a ptr as well |
| // as accessing of components: |
| enum deref_kind {deref_ptr(ptr_kind), deref_comp(comp_kind)} |
| |
| // Categorizes a derefable type. Note that we include vectors and strings as |
| // derefable (we model an index as the combination of a deref and then a |
| // pointer adjustment). |
| fn opt_deref_kind(t: ty::t) -> Option<deref_kind> { |
| match ty::get(t).sty { |
| ty::ty_uniq(*) | |
| ty::ty_evec(_, ty::vstore_uniq) | |
| ty::ty_estr(ty::vstore_uniq) => { |
| Some(deref_ptr(uniq_ptr)) |
| } |
| |
| ty::ty_rptr(r, _) | |
| ty::ty_evec(_, ty::vstore_slice(r)) | |
| ty::ty_estr(ty::vstore_slice(r)) => { |
| Some(deref_ptr(region_ptr(r))) |
| } |
| |
| ty::ty_box(*) | |
| ty::ty_evec(_, ty::vstore_box) | |
| ty::ty_estr(ty::vstore_box) => { |
| Some(deref_ptr(gc_ptr)) |
| } |
| |
| ty::ty_ptr(*) => { |
| Some(deref_ptr(unsafe_ptr)) |
| } |
| |
| ty::ty_enum(did, _) => { |
| Some(deref_comp(comp_variant(did))) |
| } |
| |
| ty::ty_evec(mt, ty::vstore_fixed(_)) => { |
| Some(deref_comp(comp_index(t, mt.mutbl))) |
| } |
| |
| ty::ty_estr(ty::vstore_fixed(_)) => { |
| Some(deref_comp(comp_index(t, m_imm))) |
| } |
| |
| _ => None |
| } |
| } |
| |
| fn deref_kind(tcx: ty::ctxt, t: ty::t) -> deref_kind { |
| match opt_deref_kind(t) { |
| Some(k) => k, |
| None => { |
| tcx.sess.bug( |
| fmt!("deref_cat() invoked on non-derefable type %s", |
| ty_to_str(tcx, t))); |
| } |
| } |
| } |
| |
| fn cat_expr( |
| tcx: ty::ctxt, |
| method_map: typeck::method_map, |
| expr: @ast::expr) -> cmt { |
| |
| let mcx = &mem_categorization_ctxt { |
| tcx: tcx, method_map: method_map |
| }; |
| return mcx.cat_expr(expr); |
| } |
| |
| fn cat_def( |
| tcx: ty::ctxt, |
| method_map: typeck::method_map, |
| expr_id: ast::node_id, |
| expr_span: span, |
| expr_ty: ty::t, |
| def: ast::def) -> cmt { |
| |
| let mcx = &mem_categorization_ctxt { |
| tcx: tcx, method_map: method_map |
| }; |
| return mcx.cat_def(expr_id, expr_span, expr_ty, def); |
| } |
| |
| fn cat_variant<N: ast_node>( |
| tcx: ty::ctxt, |
| method_map: typeck::method_map, |
| arg: N, |
| enum_did: ast::def_id, |
| cmt: cmt) -> cmt { |
| |
| let mcx = &mem_categorization_ctxt { |
| tcx: tcx, method_map: method_map |
| }; |
| return mcx.cat_variant(arg, enum_did, cmt); |
| } |
| |
| trait ast_node { |
| fn id() -> ast::node_id; |
| fn span() -> span; |
| } |
| |
| impl @ast::expr: ast_node { |
| fn id() -> ast::node_id { self.id } |
| fn span() -> span { self.span } |
| } |
| |
| impl @ast::pat: ast_node { |
| fn id() -> ast::node_id { self.id } |
| fn span() -> span { self.span } |
| } |
| |
| trait get_type_for_node { |
| fn ty<N: ast_node>(node: N) -> ty::t; |
| } |
| |
| impl ty::ctxt: get_type_for_node { |
| fn ty<N: ast_node>(node: N) -> ty::t { |
| ty::node_id_to_type(self, node.id()) |
| } |
| } |
| |
| struct mem_categorization_ctxt { |
| tcx: ty::ctxt, |
| method_map: typeck::method_map, |
| } |
| |
| impl &mem_categorization_ctxt { |
| fn cat_expr(expr: @ast::expr) -> cmt { |
| match self.tcx.adjustments.find(expr.id) { |
| None => { |
| // No adjustments. |
| self.cat_expr_unadjusted(expr) |
| } |
| |
| Some(adjustment) => { |
| match adjustment.autoref { |
| Some(_) => { |
| // Equivalent to &*expr or something similar. |
| // This is an rvalue, effectively. |
| let expr_ty = ty::expr_ty(self.tcx, expr); |
| self.cat_rvalue(expr, expr_ty) |
| } |
| None => { |
| // Equivalent to *expr or something similar. |
| self.cat_expr_autoderefd(expr, adjustment) |
| } |
| } |
| } |
| } |
| } |
| |
| fn cat_expr_autoderefd(expr: @ast::expr, |
| adjustment: &ty::AutoAdjustment) -> cmt { |
| let mut cmt = self.cat_expr_unadjusted(expr); |
| for uint::range(1, adjustment.autoderefs+1) |deref| { |
| cmt = self.cat_deref(expr, cmt, deref); |
| } |
| return cmt; |
| } |
| |
| fn cat_expr_unadjusted(expr: @ast::expr) -> cmt { |
| debug!("cat_expr: id=%d expr=%s", |
| expr.id, pprust::expr_to_str(expr, self.tcx.sess.intr())); |
| |
| let tcx = self.tcx; |
| let expr_ty = tcx.ty(expr); |
| match expr.node { |
| ast::expr_unary(ast::deref, e_base) => { |
| if self.method_map.contains_key(expr.id) { |
| return self.cat_rvalue(expr, expr_ty); |
| } |
| |
| let base_cmt = self.cat_expr(e_base); |
| self.cat_deref(expr, base_cmt, 0) |
| } |
| |
| ast::expr_field(base, f_name, _) => { |
| if self.method_map.contains_key(expr.id) { |
| return self.cat_method_ref(expr, expr_ty); |
| } |
| |
| let base_cmt = self.cat_expr(base); |
| self.cat_field(expr, base_cmt, f_name) |
| } |
| |
| ast::expr_index(base, _) => { |
| if self.method_map.contains_key(expr.id) { |
| return self.cat_rvalue(expr, expr_ty); |
| } |
| |
| let base_cmt = self.cat_expr(base); |
| self.cat_index(expr, base_cmt) |
| } |
| |
| ast::expr_path(_) => { |
| let def = self.tcx.def_map.get(expr.id); |
| self.cat_def(expr.id, expr.span, expr_ty, def) |
| } |
| |
| ast::expr_addr_of(*) | ast::expr_call(*) | |
| ast::expr_swap(*) | ast::expr_move(*) | ast::expr_assign(*) | |
| ast::expr_assign_op(*) | ast::expr_fn(*) | ast::expr_fn_block(*) | |
| ast::expr_assert(*) | ast::expr_ret(*) | |
| ast::expr_loop_body(*) | ast::expr_do_body(*) | ast::expr_unary(*) | |
| ast::expr_copy(*) | ast::expr_cast(*) | ast::expr_fail(*) | |
| ast::expr_vstore(*) | ast::expr_vec(*) | ast::expr_tup(*) | |
| ast::expr_if(*) | ast::expr_log(*) | |
| ast::expr_binary(*) | ast::expr_while(*) | |
| ast::expr_block(*) | ast::expr_loop(*) | ast::expr_match(*) | |
| ast::expr_lit(*) | ast::expr_break(*) | ast::expr_mac(*) | |
| ast::expr_again(*) | ast::expr_rec(*) | ast::expr_struct(*) | |
| ast::expr_unary_move(*) | ast::expr_repeat(*) => { |
| return self.cat_rvalue(expr, expr_ty); |
| } |
| } |
| } |
| |
| fn cat_def(id: ast::node_id, |
| span: span, |
| expr_ty: ty::t, |
| def: ast::def) -> cmt { |
| match def { |
| ast::def_fn(*) | ast::def_static_method(*) | ast::def_mod(_) | |
| ast::def_foreign_mod(_) | ast::def_const(_) | |
| ast::def_use(_) | ast::def_variant(*) | |
| ast::def_ty(_) | ast::def_prim_ty(_) | |
| ast::def_ty_param(*) | ast::def_class(*) | |
| ast::def_typaram_binder(*) | ast::def_region(_) | |
| ast::def_label(_) => { |
| @{id:id, span:span, |
| cat:cat_special(sk_static_item), lp:None, |
| mutbl:m_imm, ty:expr_ty} |
| } |
| |
| ast::def_arg(vid, mode) => { |
| // Idea: make this could be rewritten to model by-ref |
| // stuff as `&const` and `&mut`? |
| |
| // m: mutability of the argument |
| // lp: loan path, must be none for aliasable things |
| let {m,lp} = match ty::resolved_mode(self.tcx, mode) { |
| ast::by_move | ast::by_copy => { |
| {m: m_imm, lp: Some(@lp_arg(vid))} |
| } |
| ast::by_ref => { |
| {m: m_imm, lp: None} |
| } |
| ast::by_val => { |
| // by-value is this hybrid mode where we have a |
| // pointer but we do not own it. This is not |
| // considered loanable because, for example, a by-ref |
| // and and by-val argument might both actually contain |
| // the same unique ptr. |
| {m: m_imm, lp: None} |
| } |
| }; |
| @{id:id, span:span, |
| cat:cat_arg(vid), lp:lp, |
| mutbl:m, ty:expr_ty} |
| } |
| |
| ast::def_self(_) => { |
| @{id:id, span:span, |
| cat:cat_special(sk_self), lp:None, |
| mutbl:m_imm, ty:expr_ty} |
| } |
| |
| ast::def_upvar(_, inner, fn_node_id, _) => { |
| let ty = ty::node_id_to_type(self.tcx, fn_node_id); |
| let proto = ty::ty_fn_proto(ty); |
| match proto { |
| ty::proto_vstore(ty::vstore_slice(_)) => { |
| let upcmt = self.cat_def(id, span, expr_ty, *inner); |
| @{id:id, span:span, |
| cat:cat_stack_upvar(upcmt), lp:upcmt.lp, |
| mutbl:upcmt.mutbl, ty:upcmt.ty} |
| } |
| ty::proto_bare | |
| ty::proto_vstore(ty::vstore_uniq) | |
| ty::proto_vstore(ty::vstore_box) => { |
| // FIXME #2152 allow mutation of moved upvars |
| @{id:id, span:span, |
| cat:cat_special(sk_heap_upvar), lp:None, |
| mutbl:m_imm, ty:expr_ty} |
| } |
| ty::proto_vstore(ty::vstore_fixed(_)) => |
| fail ~"fixed vstore not allowed here" |
| } |
| } |
| |
| ast::def_local(vid, mutbl) => { |
| let m = if mutbl {m_mutbl} else {m_imm}; |
| @{id:id, span:span, |
| cat:cat_local(vid), lp:Some(@lp_local(vid)), |
| mutbl:m, ty:expr_ty} |
| } |
| |
| ast::def_binding(vid, ast::bind_by_value) | |
| ast::def_binding(vid, ast::bind_by_move) | |
| ast::def_binding(vid, ast::bind_by_ref(_)) => { |
| // by-value/by-ref bindings are local variables |
| @{id:id, span:span, |
| cat:cat_local(vid), lp:Some(@lp_local(vid)), |
| mutbl:m_imm, ty:expr_ty} |
| } |
| |
| ast::def_binding(pid, ast::bind_by_implicit_ref) => { |
| // implicit-by-ref bindings are "special" since they are |
| // implicit pointers. |
| |
| // Technically, the mutability is not always imm, but we |
| // (choose to be) unsound for the moment since these |
| // implicit refs are going away and it reduces external |
| // dependencies. |
| |
| @{id:id, span:span, |
| cat:cat_binding(pid), lp:None, |
| mutbl:m_imm, ty:expr_ty} |
| } |
| } |
| } |
| |
| fn cat_variant<N: ast_node>(arg: N, |
| enum_did: ast::def_id, |
| cmt: cmt) -> cmt { |
| @{id: arg.id(), span: arg.span(), |
| cat: cat_comp(cmt, comp_variant(enum_did)), |
| lp: cmt.lp.map(|l| @lp_comp(*l, comp_variant(enum_did)) ), |
| mutbl: cmt.mutbl, // imm iff in an immutable context |
| ty: self.tcx.ty(arg)} |
| } |
| |
| fn cat_rvalue(expr: @ast::expr, expr_ty: ty::t) -> cmt { |
| @{id:expr.id, span:expr.span, |
| cat:cat_rvalue, lp:None, |
| mutbl:m_imm, ty:expr_ty} |
| } |
| |
| /// inherited mutability: used in cases where the mutability of a |
| /// component is inherited from the base it is a part of. For |
| /// example, a record field is mutable if it is declared mutable |
| /// or if the container is mutable. |
| fn inherited_mutability(base_m: ast::mutability, |
| comp_m: ast::mutability) -> ast::mutability { |
| match comp_m { |
| m_imm => {base_m} // imm: as mutable as the container |
| m_mutbl | m_const => {comp_m} |
| } |
| } |
| |
| fn cat_field<N:ast_node>(node: N, base_cmt: cmt, |
| f_name: ast::ident) -> cmt { |
| let f_mutbl = match field_mutbl(self.tcx, base_cmt.ty, f_name) { |
| Some(f_mutbl) => f_mutbl, |
| None => { |
| self.tcx.sess.span_bug( |
| node.span(), |
| fmt!("Cannot find field `%s` in type `%s`", |
| self.tcx.sess.str_of(f_name), |
| ty_to_str(self.tcx, base_cmt.ty))); |
| } |
| }; |
| let m = self.inherited_mutability(base_cmt.mutbl, f_mutbl); |
| let f_comp = comp_field(f_name, f_mutbl); |
| let lp = base_cmt.lp.map(|lp| @lp_comp(*lp, f_comp) ); |
| @{id: node.id(), span: node.span(), |
| cat: cat_comp(base_cmt, f_comp), lp:lp, |
| mutbl: m, ty: self.tcx.ty(node)} |
| } |
| |
| fn cat_deref<N:ast_node>(node: N, |
| base_cmt: cmt, |
| deref_cnt: uint) -> cmt { |
| let mt = match ty::deref(self.tcx, base_cmt.ty, true) { |
| Some(mt) => mt, |
| None => { |
| self.tcx.sess.span_bug( |
| node.span(), |
| fmt!("Explicit deref of non-derefable type: %s", |
| ty_to_str(self.tcx, base_cmt.ty))); |
| } |
| }; |
| |
| match deref_kind(self.tcx, base_cmt.ty) { |
| deref_ptr(ptr) => { |
| let lp = do base_cmt.lp.chain_ref |l| { |
| // Given that the ptr itself is loanable, we can |
| // loan out deref'd uniq ptrs as the data they are |
| // the only way to reach the data they point at. |
| // Other ptr types admit aliases and are therefore |
| // not loanable. |
| match ptr { |
| uniq_ptr => {Some(@lp_deref(*l, ptr))} |
| gc_ptr | region_ptr(_) | unsafe_ptr => {None} |
| } |
| }; |
| |
| // for unique ptrs, we inherit mutability from the |
| // owning reference. |
| let m = match ptr { |
| uniq_ptr => { |
| self.inherited_mutability(base_cmt.mutbl, mt.mutbl) |
| } |
| gc_ptr | region_ptr(_) | unsafe_ptr => { |
| mt.mutbl |
| } |
| }; |
| |
| @{id:node.id(), span:node.span(), |
| cat:cat_deref(base_cmt, deref_cnt, ptr), lp:lp, |
| mutbl:m, ty:mt.ty} |
| } |
| |
| deref_comp(comp) => { |
| let lp = base_cmt.lp.map(|l| @lp_comp(*l, comp) ); |
| let m = self.inherited_mutability(base_cmt.mutbl, mt.mutbl); |
| @{id:node.id(), span:node.span(), |
| cat:cat_comp(base_cmt, comp), lp:lp, |
| mutbl:m, ty:mt.ty} |
| } |
| } |
| } |
| |
| fn cat_index(expr: @ast::expr, base_cmt: cmt) -> cmt { |
| let mt = match ty::index(self.tcx, base_cmt.ty) { |
| Some(mt) => mt, |
| None => { |
| self.tcx.sess.span_bug( |
| expr.span, |
| fmt!("Explicit index of non-index type `%s`", |
| ty_to_str(self.tcx, base_cmt.ty))); |
| } |
| }; |
| |
| return match deref_kind(self.tcx, base_cmt.ty) { |
| deref_ptr(ptr) => { |
| // (a) the contents are loanable if the base is loanable |
| // and this is a *unique* vector |
| let deref_lp = match ptr { |
| uniq_ptr => {base_cmt.lp.map(|lp| @lp_deref(*lp, uniq_ptr))} |
| _ => {None} |
| }; |
| |
| // (b) for unique ptrs, we inherit mutability from the |
| // owning reference. |
| let m = match ptr { |
| uniq_ptr => { |
| self.inherited_mutability(base_cmt.mutbl, mt.mutbl) |
| } |
| gc_ptr | region_ptr(_) | unsafe_ptr => { |
| mt.mutbl |
| } |
| }; |
| |
| // (c) the deref is explicit in the resulting cmt |
| let deref_cmt = @{id:expr.id, span:expr.span, |
| cat:cat_deref(base_cmt, 0u, ptr), lp:deref_lp, |
| mutbl:m, ty:mt.ty}; |
| |
| comp(expr, deref_cmt, base_cmt.ty, m, mt.ty) |
| } |
| |
| deref_comp(_) => { |
| // fixed-length vectors have no deref |
| comp(expr, base_cmt, base_cmt.ty, mt.mutbl, mt.ty) |
| } |
| }; |
| |
| fn comp(expr: @ast::expr, of_cmt: cmt, |
| vect: ty::t, mutbl: ast::mutability, ty: ty::t) -> cmt { |
| let comp = comp_index(vect, mutbl); |
| let index_lp = of_cmt.lp.map(|lp| @lp_comp(*lp, comp) ); |
| @{id:expr.id, span:expr.span, |
| cat:cat_comp(of_cmt, comp), lp:index_lp, |
| mutbl:mutbl, ty:ty} |
| } |
| } |
| |
| fn cat_tuple_elt<N: ast_node>(elt: N, cmt: cmt) -> cmt { |
| @{id: elt.id(), span: elt.span(), |
| cat: cat_comp(cmt, comp_tuple), |
| lp: cmt.lp.map(|l| @lp_comp(*l, comp_tuple) ), |
| mutbl: cmt.mutbl, // imm iff in an immutable context |
| ty: self.tcx.ty(elt)} |
| } |
| |
| fn cat_method_ref(expr: @ast::expr, expr_ty: ty::t) -> cmt { |
| @{id:expr.id, span:expr.span, |
| cat:cat_special(sk_method), lp:None, |
| mutbl:m_imm, ty:expr_ty} |
| } |
| |
| fn cat_pattern(cmt: cmt, pat: @ast::pat, op: fn(cmt, @ast::pat)) { |
| |
| op(cmt, pat); |
| |
| // Here, `cmt` is the categorization for the value being |
| // matched and pat is the pattern it is being matched against. |
| // |
| // In general, the way that this works is that we walk down |
| // the pattern, constructing a cmt that represents the path |
| // that will be taken to reach the value being matched. |
| // |
| // When we encounter named bindings, we take the cmt that has |
| // been built up and pass it off to guarantee_valid() so that |
| // we can be sure that the binding will remain valid for the |
| // duration of the arm. |
| // |
| // The correspondence between the id in the cmt and which |
| // pattern is being referred to is somewhat...subtle. In |
| // general, the id of the cmt is the id of the node that |
| // produces the value. For patterns, that's actually the |
| // *subpattern*, generally speaking. |
| // |
| // To see what I mean about ids etc, consider: |
| // |
| // let x = @@3; |
| // match x { |
| // @@y { ... } |
| // } |
| // |
| // Here the cmt for `y` would be something like |
| // |
| // local(x)->@->@ |
| // |
| // where the id of `local(x)` is the id of the `x` that appears |
| // in the alt, the id of `local(x)->@` is the `@y` pattern, |
| // and the id of `local(x)->@->@` is the id of the `y` pattern. |
| |
| |
| let _i = indenter(); |
| let tcx = self.tcx; |
| debug!("cat_pattern: id=%d pat=%s cmt=%s", |
| pat.id, pprust::pat_to_str(pat, tcx.sess.intr()), |
| self.cmt_to_repr(cmt)); |
| |
| match pat.node { |
| ast::pat_wild => { |
| // _ |
| } |
| |
| ast::pat_enum(_, None) => { |
| // variant(*) |
| } |
| ast::pat_enum(_, Some(subpats)) => { |
| // variant(x, y, z) |
| let enum_did = match self.tcx.def_map.find(pat.id) { |
| Some(ast::def_variant(enum_did, _)) => enum_did, |
| e => tcx.sess.span_bug(pat.span, |
| fmt!("resolved to %?, not variant", e)) |
| }; |
| |
| for subpats.each |subpat| { |
| let subcmt = self.cat_variant(*subpat, enum_did, cmt); |
| self.cat_pattern(subcmt, *subpat, op); |
| } |
| } |
| |
| ast::pat_ident(_, _, Some(subpat)) => { |
| self.cat_pattern(cmt, subpat, op); |
| } |
| |
| ast::pat_ident(_, _, None) => { |
| // nullary variant or identifier: ignore |
| } |
| |
| ast::pat_rec(field_pats, _) => { |
| // {f1: p1, ..., fN: pN} |
| for field_pats.each |fp| { |
| let cmt_field = self.cat_field(fp.pat, cmt, fp.ident); |
| self.cat_pattern(cmt_field, fp.pat, op); |
| } |
| } |
| |
| ast::pat_struct(_, field_pats, _) => { |
| // {f1: p1, ..., fN: pN} |
| for field_pats.each |fp| { |
| let cmt_field = self.cat_field(fp.pat, cmt, fp.ident); |
| self.cat_pattern(cmt_field, fp.pat, op); |
| } |
| } |
| |
| ast::pat_tup(subpats) => { |
| // (p1, ..., pN) |
| for subpats.each |subpat| { |
| let subcmt = self.cat_tuple_elt(*subpat, cmt); |
| self.cat_pattern(subcmt, *subpat, op); |
| } |
| } |
| |
| ast::pat_box(subpat) | ast::pat_uniq(subpat) | |
| ast::pat_region(subpat) => { |
| // @p1, ~p1 |
| let subcmt = self.cat_deref(subpat, cmt, 0); |
| self.cat_pattern(subcmt, subpat, op); |
| } |
| |
| ast::pat_lit(_) | ast::pat_range(_, _) => { /*always ok*/ } |
| } |
| } |
| |
| fn cat_to_repr(cat: categorization) -> ~str { |
| match cat { |
| cat_special(sk_method) => ~"method", |
| cat_special(sk_static_item) => ~"static_item", |
| cat_special(sk_self) => ~"self", |
| cat_special(sk_heap_upvar) => ~"heap-upvar", |
| cat_stack_upvar(_) => ~"stack-upvar", |
| cat_rvalue => ~"rvalue", |
| cat_local(node_id) => fmt!("local(%d)", node_id), |
| cat_binding(node_id) => fmt!("binding(%d)", node_id), |
| cat_arg(node_id) => fmt!("arg(%d)", node_id), |
| cat_deref(cmt, derefs, ptr) => { |
| fmt!("%s->(%s, %u)", self.cat_to_repr(cmt.cat), |
| self.ptr_sigil(ptr), derefs) |
| } |
| cat_comp(cmt, comp) => { |
| fmt!("%s.%s", self.cat_to_repr(cmt.cat), self.comp_to_repr(comp)) |
| } |
| cat_discr(cmt, _) => self.cat_to_repr(cmt.cat) |
| } |
| } |
| |
| fn mut_to_str(mutbl: ast::mutability) -> ~str { |
| match mutbl { |
| m_mutbl => ~"mutable", |
| m_const => ~"const", |
| m_imm => ~"immutable" |
| } |
| } |
| |
| fn ptr_sigil(ptr: ptr_kind) -> ~str { |
| match ptr { |
| uniq_ptr => ~"~", |
| gc_ptr => ~"@", |
| region_ptr(_) => ~"&", |
| unsafe_ptr => ~"*" |
| } |
| } |
| |
| fn comp_to_repr(comp: comp_kind) -> ~str { |
| match comp { |
| comp_field(fld, _) => self.tcx.sess.str_of(fld), |
| comp_index(*) => ~"[]", |
| comp_tuple => ~"()", |
| comp_variant(_) => ~"<enum>" |
| } |
| } |
| |
| fn lp_to_str(lp: @loan_path) -> ~str { |
| match *lp { |
| lp_local(node_id) => { |
| fmt!("local(%d)", node_id) |
| } |
| lp_arg(node_id) => { |
| fmt!("arg(%d)", node_id) |
| } |
| lp_deref(lp, ptr) => { |
| fmt!("%s->(%s)", self.lp_to_str(lp), |
| self.ptr_sigil(ptr)) |
| } |
| lp_comp(lp, comp) => { |
| fmt!("%s.%s", self.lp_to_str(lp), |
| self.comp_to_repr(comp)) |
| } |
| } |
| } |
| |
| fn cmt_to_repr(cmt: cmt) -> ~str { |
| fmt!("{%s id:%d m:%s lp:%s ty:%s}", |
| self.cat_to_repr(cmt.cat), |
| cmt.id, |
| self.mut_to_str(cmt.mutbl), |
| cmt.lp.map_default(~"none", |p| self.lp_to_str(*p) ), |
| ty_to_str(self.tcx, cmt.ty)) |
| } |
| |
| fn cmt_to_str(cmt: cmt) -> ~str { |
| let mut_str = self.mut_to_str(cmt.mutbl); |
| match cmt.cat { |
| cat_special(sk_method) => ~"method", |
| cat_special(sk_static_item) => ~"static item", |
| cat_special(sk_self) => ~"self reference", |
| cat_special(sk_heap_upvar) => { |
| ~"captured outer variable in a heap closure" |
| } |
| cat_rvalue => ~"non-lvalue", |
| cat_local(_) => mut_str + ~" local variable", |
| cat_binding(_) => ~"pattern binding", |
| cat_arg(_) => ~"argument", |
| cat_deref(_, _, pk) => fmt!("dereference of %s %s pointer", |
| mut_str, self.ptr_sigil(pk)), |
| cat_stack_upvar(_) => { |
| ~"captured outer " + mut_str + ~" variable in a stack closure" |
| } |
| cat_comp(_, comp_field(*)) => mut_str + ~" field", |
| cat_comp(_, comp_tuple) => ~"tuple content", |
| cat_comp(_, comp_variant(_)) => ~"enum content", |
| cat_comp(_, comp_index(t, _)) => { |
| match ty::get(t).sty { |
| ty::ty_evec(*) => mut_str + ~" vec content", |
| ty::ty_estr(*) => mut_str + ~" str content", |
| _ => mut_str + ~" indexed content" |
| } |
| } |
| cat_discr(cmt, _) => { |
| self.cmt_to_str(cmt) |
| } |
| } |
| } |
| |
| fn region_to_str(r: ty::region) -> ~str { |
| region_to_str(self.tcx, r) |
| } |
| } |
| |
| fn field_mutbl(tcx: ty::ctxt, |
| base_ty: ty::t, |
| f_name: ast::ident) -> Option<ast::mutability> { |
| // Need to refactor so that records/class fields can be treated uniformly. |
| match ty::get(base_ty).sty { |
| ty::ty_rec(fields) => { |
| for fields.each |f| { |
| if f.ident == f_name { |
| return Some(f.mt.mutbl); |
| } |
| } |
| } |
| ty::ty_class(did, _) => { |
| for ty::lookup_class_fields(tcx, did).each |fld| { |
| if fld.ident == f_name { |
| let m = match fld.mutability { |
| ast::class_mutable => ast::m_mutbl, |
| ast::class_immutable => ast::m_imm |
| }; |
| return Some(m); |
| } |
| } |
| } |
| _ => { } |
| } |
| |
| return None; |
| } |
