// Copyright 2012 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. /*! * * # Compilation of match statements * * I will endeavor to explain the code as best I can. I have only a loose * understanding of some parts of it. * * ## Matching * * The basic state of the code is maintained in an array `m` of `@Match` * objects. Each `@Match` describes some list of patterns, all of which must * match against the current list of values. If those patterns match, then * the arm listed in the match is the correct arm. A given arm may have * multiple corresponding match entries, one for each alternative that * remains. As we proceed these sets of matches are adjusted by the various * `enter_XXX()` functions, each of which adjusts the set of options given * some information about the value which has been matched. * * So, initially, there is one value and N matches, each of which have one * constituent pattern. N here is usually the number of arms but may be * greater, if some arms have multiple alternatives. For example, here: * * enum Foo { A, B(int), C(uint, uint) } * match foo { * A => ..., * B(x) => ..., * C(1u, 2) => ..., * C(_) => ... * } * * The value would be `foo`. There would be four matches, each of which * contains one pattern (and, in one case, a guard). We could collect the * various options and then compile the code for the case where `foo` is an * `A`, a `B`, and a `C`. When we generate the code for `C`, we would (1) * drop the two matches that do not match a `C` and (2) expand the other two * into two patterns each. In the first case, the two patterns would be `1u` * and `2`, and the in the second case the _ pattern would be expanded into * `_` and `_`. The two values are of course the arguments to `C`. * * Here is a quick guide to the various functions: * * - `compile_submatch()`: The main workhouse. It takes a list of values and * a list of matches and finds the various possibilities that could occur. * * - `enter_XXX()`: modifies the list of matches based on some information * about the value that has been matched. For example, * `enter_rec_or_struct()` adjusts the values given that a record or struct * has been matched. This is an infallible pattern, so *all* of the matches * must be either wildcards or record/struct patterns. `enter_opt()` * handles the fallible cases, and it is correspondingly more complex. * * ## Bindings * * We store information about the bound variables for each arm as part of the * per-arm `ArmData` struct. There is a mapping from identifiers to * `BindingInfo` structs. These structs contain the mode/id/type of the * binding, but they also contain up to two LLVM values, called `llmatch` and * `llbinding` respectively (the `llbinding`, as will be described shortly, is * optional and only present for by-value bindings---therefore it is bundled * up as part of the `TransBindingMode` type). Both point at allocas. * * The `llmatch` binding always stores a pointer into the value being matched * which points at the data for the binding. If the value being matched has * type `T`, then, `llmatch` will point at an alloca of type `T*` (and hence * `llmatch` has type `T**`). So, if you have a pattern like: * * let a: A = ...; * let b: B = ...; * match (a, b) { (ref c, copy d) => { ... } } * * For `c` and `d`, we would generate allocas of type `C*` and `D*` * respectively. These are called the `llmatch`. As we match, when we come * up against an identifier, we store the current pointer into the * corresponding alloca. * * In addition, for each by-value binding (copy or move), we will create a * second alloca (`llbinding`) that will hold the final value. In this * example, that means that `d` would have this second alloca of type `D` (and * hence `llbinding` has type `D*`). * * Once a pattern is completely matched, and assuming that there is no guard * pattern, we will branch to a block that leads to the body itself. For any * by-value bindings, this block will first load the ptr from `llmatch` (the * one of type `D*`) and copy/move the value into `llbinding` (the one of type * `D`). The second alloca then becomes the value of the local variable. For * by ref bindings, the value of the local variable is simply the first * alloca. * * So, for the example above, we would generate a setup kind of like this: * * +-------+ * | Entry | * +-------+ * | * +-------------------------------------------+ * | llmatch_c = (addr of first half of tuple) | * | llmatch_d = (addr of first half of tuple) | * +-------------------------------------------+ * | * +--------------------------------------+ * | *llbinding_d = **llmatch_dlbinding_d | * +--------------------------------------+ * * If there is a guard, the situation is slightly different, because we must * execute the guard code. Moreover, we need to do so once for each of the * alternatives that lead to the arm, because if the guard fails, they may * have different points from which to continue the search. Therefore, in that * case, we generate code that looks more like: * * +-------+ * | Entry | * +-------+ * | * +-------------------------------------------+ * | llmatch_c = (addr of first half of tuple) | * | llmatch_d = (addr of first half of tuple) | * +-------------------------------------------+ * | * +-------------------------------------------------+ * | *llbinding_d = **llmatch_dlbinding_d | * | check condition | * | if false { free *llbinding_d, goto next case } | * | if true { goto body } | * +-------------------------------------------------+ * * The handling for the cleanups is a bit... sensitive. Basically, the body * is the one that invokes `add_clean()` for each binding. During the guard * evaluation, we add temporary cleanups and revoke them after the guard is * evaluated (it could fail, after all). Presuming the guard fails, we drop * the various values we copied explicitly. Note that guards and moves are * just plain incompatible. * */ use core::prelude::*; use back::abi; use lib::llvm::llvm; use lib::llvm::{ValueRef, BasicBlockRef}; use middle::const_eval; use middle::pat_util::*; use middle::resolve::DefMap; use middle::trans::base::*; use middle::trans::build::*; use middle::trans::callee; use middle::trans::common::*; use middle::trans::consts; use middle::trans::controlflow; use middle::trans::datum::*; use middle::trans::expr::Dest; use middle::trans::expr; use middle::trans::glue; use util::common::indenter; use core::dvec::DVec; use core::dvec; use std::oldmap::HashMap; use syntax::ast::def_id; use syntax::ast; use syntax::ast_util::{dummy_sp, path_to_ident}; use syntax::ast_util; use syntax::codemap::span; use syntax::print::pprust::pat_to_str; pub fn macros() { // FIXME(#3114): Macro import/export. include!("macros.rs"); } // An option identifying a literal: either a unit-like struct or an // expression. pub enum Lit { UnitLikeStructLit(ast::node_id), // the node ID of the pattern ExprLit(@ast::expr), ConstLit(ast::def_id), // the def ID of the constant } // An option identifying a branch (either a literal, a enum variant or a // range) pub enum Opt { lit(Lit), var(/* disr val */int, /* variant dids */{enm: def_id, var: def_id}), range(@ast::expr, @ast::expr), vec_len_eq(uint), vec_len_ge(uint) } pub fn opt_eq(tcx: ty::ctxt, a: &Opt, b: &Opt) -> bool { match (*a, *b) { (lit(a), lit(b)) => { match (a, b) { (UnitLikeStructLit(a), UnitLikeStructLit(b)) => a == b, _ => { let a_expr; match a { ExprLit(existing_a_expr) => a_expr = existing_a_expr, ConstLit(a_const) => { let e = const_eval::lookup_const_by_id(tcx, a_const); a_expr = e.get(); } UnitLikeStructLit(_) => { fail!(~"UnitLikeStructLit should have been handled \ above") } } let b_expr; match b { ExprLit(existing_b_expr) => b_expr = existing_b_expr, ConstLit(b_const) => { let e = const_eval::lookup_const_by_id(tcx, b_const); b_expr = e.get(); } UnitLikeStructLit(_) => { fail!(~"UnitLikeStructLit should have been handled \ above") } } const_eval::compare_lit_exprs(tcx, a_expr, b_expr) == 0 } } } (range(a1, a2), range(b1, b2)) => { const_eval::compare_lit_exprs(tcx, a1, b1) == 0 && const_eval::compare_lit_exprs(tcx, a2, b2) == 0 } (var(a, _), var(b, _)) => a == b, (vec_len_eq(a), vec_len_eq(b)) => a == b, (vec_len_ge(a), vec_len_ge(b)) => a == b, _ => false } } pub enum opt_result { single_result(Result), lower_bound(Result), range_result(Result, Result), } pub fn trans_opt(bcx: block, o: &Opt) -> opt_result { let _icx = bcx.insn_ctxt("match::trans_opt"); let ccx = bcx.ccx(); let mut bcx = bcx; match *o { lit(ExprLit(lit_expr)) => { let datumblock = expr::trans_to_datum(bcx, lit_expr); return single_result(datumblock.to_result()); } lit(UnitLikeStructLit(pat_id)) => { let struct_ty = ty::node_id_to_type(bcx.tcx(), pat_id); let datumblock = datum::scratch_datum(bcx, struct_ty, true); return single_result(datumblock.to_result(bcx)); } lit(ConstLit(lit_id)) => { let llval = consts::get_const_val(bcx.ccx(), lit_id); return single_result(rslt(bcx, llval)); } var(disr_val, _) => { return single_result(rslt(bcx, C_int(ccx, disr_val))); } range(l1, l2) => { return range_result(rslt(bcx, consts::const_expr(ccx, l1)), rslt(bcx, consts::const_expr(ccx, l2))); } vec_len_eq(n) => { return single_result(rslt(bcx, C_int(ccx, n as int))); } vec_len_ge(n) => { return lower_bound(rslt(bcx, C_int(ccx, n as int))); } } } pub fn variant_opt(tcx: ty::ctxt, pat_id: ast::node_id) -> Opt { match tcx.def_map.get(&pat_id) { ast::def_variant(enum_id, var_id) => { let variants = ty::enum_variants(tcx, enum_id); for vec::each(*variants) |v| { if var_id == v.id { return var(v.disr_val, {enm: enum_id, var: var_id}); } } ::core::util::unreachable(); } ast::def_struct(_) => { return lit(UnitLikeStructLit(pat_id)); } _ => { tcx.sess.bug(~"non-variant or struct in variant_opt()"); } } } pub enum TransBindingMode { TrByValue(/*ismove:*/ bool, /*llbinding:*/ ValueRef), TrByRef, TrByImplicitRef } /** * Information about a pattern binding: * - `llmatch` is a pointer to a stack slot. The stack slot contains a * pointer into the value being matched. Hence, llmatch has type `T**` * where `T` is the value being matched. * - `trmode` is the trans binding mode * - `id` is the node id of the binding * - `ty` is the Rust type of the binding */ pub struct BindingInfo { llmatch: ValueRef, trmode: TransBindingMode, id: ast::node_id, ty: ty::t, } pub type BindingsMap = HashMap; pub struct ArmData { bodycx: block, arm: &ast::arm, bindings_map: BindingsMap } pub struct Match { pats: ~[@ast::pat], data: @ArmData } pub fn match_to_str(bcx: block, m: &Match) -> ~str { if bcx.sess().verbose() { // for many programs, this just take too long to serialize fmt!("%?", m.pats.map(|p| pat_to_str(*p, bcx.sess().intr()))) } else { fmt!("%u pats", m.pats.len()) } } pub fn matches_to_str(bcx: block, m: &[@Match]) -> ~str { fmt!("%?", m.map(|n| match_to_str(bcx, *n))) } pub fn has_nested_bindings(m: &[@Match], col: uint) -> bool { for vec::each(m) |br| { match br.pats[col].node { ast::pat_ident(_, _, Some(_)) => return true, _ => () } } return false; } pub fn expand_nested_bindings(bcx: block, m: &[@Match/&r], col: uint, val: ValueRef) -> ~[@Match/&r] { debug!("expand_nested_bindings(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); do m.map |br| { match br.pats[col].node { ast::pat_ident(_, path, Some(inner)) => { let pats = vec::append( vec::slice(br.pats, 0u, col).to_vec(), vec::append(~[inner], vec::slice(br.pats, col + 1u, br.pats.len()))); let binding_info = br.data.bindings_map.get(&path_to_ident(path)); Store(bcx, val, binding_info.llmatch); @Match {pats: pats, data: br.data} } _ => { *br } } } } pub type enter_pat = fn(@ast::pat) -> Option<~[@ast::pat]>; pub fn assert_is_binding_or_wild(bcx: block, p: @ast::pat) { if !pat_is_binding_or_wild(bcx.tcx().def_map, p) { bcx.sess().span_bug( p.span, fmt!("Expected an identifier pattern but found p: %s", pat_to_str(p, bcx.sess().intr()))); } } pub fn enter_match(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef, e: enter_pat) -> ~[@Match/&r] { debug!("enter_match(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let mut result = ~[]; for vec::each(m) |br| { match e(br.pats[col]) { Some(sub) => { let pats = vec::append( vec::append(sub, vec::slice(br.pats, 0u, col)), vec::slice(br.pats, col + 1u, br.pats.len())); let self = br.pats[col]; match self.node { ast::pat_ident(_, path, None) => { if pat_is_binding(dm, self) { let binding_info = br.data.bindings_map.get( &path_to_ident(path)); Store(bcx, val, binding_info.llmatch); } } _ => {} } result.push(@Match {pats: pats, data: br.data}); } None => () } } debug!("result=%s", matches_to_str(bcx, result)); return result; } pub fn enter_default(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef) -> ~[@Match/&r] { debug!("enter_default(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); do enter_match(bcx, dm, m, col, val) |p| { match p.node { ast::pat_wild | ast::pat_rec(_, _) | ast::pat_tup(_) | ast::pat_struct(*) => Some(~[]), ast::pat_ident(_, _, None) if pat_is_binding(dm, p) => Some(~[]), _ => None } } } // nmatsakis: what does enter_opt do? // in trans/match // trans/match.rs is like stumbling around in a dark cave // pcwalton: the enter family of functions adjust the set of // patterns as needed // yeah, at some point I kind of achieved some level of // understanding // anyhow, they adjust the patterns given that something of that // kind has been found // pcwalton: ok, right, so enter_XXX() adjusts the patterns, as I // said // enter_match() kind of embodies the generic code // it is provided with a function that tests each pattern to see // if it might possibly apply and so forth // so, if you have a pattern like {a: _, b: _, _} and one like _ // then _ would be expanded to (_, _) // one spot for each of the sub-patterns // enter_opt() is one of the more complex; it covers the fallible // cases // enter_rec_or_struct() or enter_tuple() are simpler, since they // are infallible patterns // so all patterns must either be records (resp. tuples) or // wildcards pub fn enter_opt(bcx: block, m: &[@Match/&r], opt: &Opt, col: uint, variant_size: uint, val: ValueRef) -> ~[@Match/&r] { debug!("enter_opt(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let tcx = bcx.tcx(); let dummy = @ast::pat {id: 0, node: ast::pat_wild, span: dummy_sp()}; do enter_match(bcx, tcx.def_map, m, col, val) |p| { match /*bad*/copy p.node { ast::pat_enum(_, subpats) => { if opt_eq(tcx, &variant_opt(tcx, p.id), opt) { Some(option::get_or_default(subpats, vec::from_elem(variant_size, dummy))) } else { None } } ast::pat_ident(_, _, None) if pat_is_variant_or_struct(tcx.def_map, p) => { if opt_eq(tcx, &variant_opt(tcx, p.id), opt) { Some(~[]) } else { None } } ast::pat_ident(_, _, None) if pat_is_const(tcx.def_map, p) => { let const_def = tcx.def_map.get(&p.id); let const_def_id = ast_util::def_id_of_def(const_def); if opt_eq(tcx, &lit(ConstLit(const_def_id)), opt) { Some(~[]) } else { None } } ast::pat_lit(l) => { if opt_eq(tcx, &lit(ExprLit(l)), opt) {Some(~[])} else {None} } ast::pat_range(l1, l2) => { if opt_eq(tcx, &range(l1, l2), opt) {Some(~[])} else {None} } ast::pat_struct(_, field_pats, _) => { if opt_eq(tcx, &variant_opt(tcx, p.id), opt) { // Look up the struct variant ID. let struct_id; match tcx.def_map.get(&p.id) { ast::def_variant(_, found_struct_id) => { struct_id = found_struct_id; } _ => { tcx.sess.span_bug(p.span, ~"expected enum \ variant def"); } } // Reorder the patterns into the same order they were // specified in the struct definition. Also fill in // unspecified fields with dummy. let reordered_patterns = dvec::DVec(); for ty::lookup_struct_fields(tcx, struct_id).each |field| { match field_pats.find(|p| p.ident == field.ident) { None => reordered_patterns.push(dummy), Some(fp) => reordered_patterns.push(fp.pat) } } Some(dvec::unwrap(reordered_patterns)) } else { None } } ast::pat_vec(elems, tail) => { match tail { Some(_) => { if opt_eq(tcx, &vec_len_ge(elems.len()), opt) { Some(vec::append_one(elems, tail.get())) } else { None } } None => { if opt_eq(tcx, &vec_len_eq(elems.len()), opt) { Some(copy elems) } else { None } } } } _ => { assert_is_binding_or_wild(bcx, p); Some(vec::from_elem(variant_size, dummy)) } } } } pub fn enter_rec_or_struct(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, fields: ~[ast::ident], val: ValueRef) -> ~[@Match/&r] { debug!("enter_rec_or_struct(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let dummy = @ast::pat {id: 0, node: ast::pat_wild, span: dummy_sp()}; do enter_match(bcx, dm, m, col, val) |p| { match /*bad*/copy p.node { ast::pat_rec(fpats, _) | ast::pat_struct(_, fpats, _) => { let mut pats = ~[]; for vec::each(fields) |fname| { match fpats.find(|p| p.ident == *fname) { None => pats.push(dummy), Some(pat) => pats.push(pat.pat) } } Some(pats) } _ => { assert_is_binding_or_wild(bcx, p); Some(vec::from_elem(fields.len(), dummy)) } } } } pub fn enter_tup(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef, n_elts: uint) -> ~[@Match/&r] { debug!("enter_tup(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let dummy = @ast::pat {id: 0, node: ast::pat_wild, span: dummy_sp()}; do enter_match(bcx, dm, m, col, val) |p| { match /*bad*/copy p.node { ast::pat_tup(elts) => { Some(elts) } _ => { assert_is_binding_or_wild(bcx, p); Some(vec::from_elem(n_elts, dummy)) } } } } pub fn enter_tuple_struct(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef, n_elts: uint) -> ~[@Match/&r] { debug!("enter_tuple_struct(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let dummy = @ast::pat {id: 0, node: ast::pat_wild, span: dummy_sp()}; do enter_match(bcx, dm, m, col, val) |p| { match /*bad*/copy p.node { ast::pat_enum(_, Some(elts)) => Some(elts), _ => { assert_is_binding_or_wild(bcx, p); Some(vec::from_elem(n_elts, dummy)) } } } } pub fn enter_box(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef) -> ~[@Match/&r] { debug!("enter_box(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let dummy = @ast::pat {id: 0, node: ast::pat_wild, span: dummy_sp()}; do enter_match(bcx, dm, m, col, val) |p| { match p.node { ast::pat_box(sub) => { Some(~[sub]) } _ => { assert_is_binding_or_wild(bcx, p); Some(~[dummy]) } } } } pub fn enter_uniq(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef) -> ~[@Match/&r] { debug!("enter_uniq(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let dummy = @ast::pat {id: 0, node: ast::pat_wild, span: dummy_sp()}; do enter_match(bcx, dm, m, col, val) |p| { match p.node { ast::pat_uniq(sub) => { Some(~[sub]) } _ => { assert_is_binding_or_wild(bcx, p); Some(~[dummy]) } } } } pub fn enter_region(bcx: block, dm: DefMap, m: &[@Match/&r], col: uint, val: ValueRef) -> ~[@Match/&r] { debug!("enter_region(bcx=%s, m=%s, col=%u, val=%?)", bcx.to_str(), matches_to_str(bcx, m), col, bcx.val_str(val)); let _indenter = indenter(); let dummy = @ast::pat { id: 0, node: ast::pat_wild, span: dummy_sp() }; do enter_match(bcx, dm, m, col, val) |p| { match p.node { ast::pat_region(sub) => { Some(~[sub]) } _ => { assert_is_binding_or_wild(bcx, p); Some(~[dummy]) } } } } // Returns the options in one column of matches. An option is something that // needs to be conditionally matched at runtime; for example, the discriminant // on a set of enum variants or a literal. pub fn get_options(ccx: @crate_ctxt, m: &[@Match], col: uint) -> ~[Opt] { fn add_to_set(tcx: ty::ctxt, set: &DVec, val: Opt) { if set.any(|l| opt_eq(tcx, l, &val)) {return;} set.push(val); } let found = DVec(); for vec::each(m) |br| { let cur = br.pats[col]; match /*bad*/copy cur.node { ast::pat_lit(l) => { add_to_set(ccx.tcx, &found, lit(ExprLit(l))); } ast::pat_ident(*) => { // This is one of: an enum variant, a unit-like struct, or a // variable binding. match ccx.tcx.def_map.find(&cur.id) { Some(ast::def_variant(*)) => { add_to_set(ccx.tcx, &found, variant_opt(ccx.tcx, cur.id)); } Some(ast::def_struct(*)) => { add_to_set(ccx.tcx, &found, lit(UnitLikeStructLit(cur.id))); } Some(ast::def_const(const_did)) => { add_to_set(ccx.tcx, &found, lit(ConstLit(const_did))); } _ => {} } } ast::pat_enum(*) | ast::pat_struct(*) => { // This could be one of: a tuple-like enum variant, a // struct-like enum variant, or a struct. match ccx.tcx.def_map.find(&cur.id) { Some(ast::def_variant(*)) => { add_to_set(ccx.tcx, &found, variant_opt(ccx.tcx, cur.id)); } _ => {} } } ast::pat_range(l1, l2) => { add_to_set(ccx.tcx, &found, range(l1, l2)); } ast::pat_vec(elems, tail) => { let opt = match tail { None => vec_len_eq(elems.len()), Some(_) => vec_len_ge(elems.len()) }; add_to_set(ccx.tcx, &found, opt); } _ => {} } } return dvec::unwrap(found); } pub fn extract_variant_args(bcx: block, pat_id: ast::node_id, vdefs: {enm: def_id, var: def_id}, val: ValueRef) -> {vals: ~[ValueRef], bcx: block} { let _icx = bcx.insn_ctxt("match::extract_variant_args"); let ccx = bcx.fcx.ccx; let enum_ty_substs = match ty::get(node_id_type(bcx, pat_id)).sty { ty::ty_enum(id, ref substs) => { assert id == vdefs.enm; /*bad*/copy (*substs).tps } _ => bcx.sess().bug(~"extract_variant_args: pattern has non-enum type") }; let mut blobptr = val; let variants = ty::enum_variants(ccx.tcx, vdefs.enm); let size = ty::enum_variant_with_id(ccx.tcx, vdefs.enm, vdefs.var).args.len(); if size > 0u && (*variants).len() != 1u { let enumptr = PointerCast(bcx, val, T_opaque_enum_ptr(ccx)); blobptr = GEPi(bcx, enumptr, [0u, 1u]); } let vdefs_tg = vdefs.enm; let vdefs_var = vdefs.var; let args = do vec::from_fn(size) |i| { GEP_enum(bcx, blobptr, vdefs_tg, vdefs_var, /*bad*/copy enum_ty_substs, i) }; return {vals: args, bcx: bcx}; } pub fn extract_vec_elems(bcx: block, pat_id: ast::node_id, elem_count: uint, tail: bool, val: ValueRef) -> {vals: ~[ValueRef], bcx: block} { let _icx = bcx.insn_ctxt("match::extract_vec_elems"); let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id)); let unboxed = load_if_immediate(bcx, val, vt.vec_ty); let (base, len) = tvec::get_base_and_len(bcx, unboxed, vt.vec_ty); let mut elems = do vec::from_fn(elem_count) |i| { GEPi(bcx, base, ~[i]) }; if tail { let tail_offset = Mul(bcx, vt.llunit_size, C_int(bcx.ccx(), elem_count as int) ); let tail_begin = tvec::pointer_add(bcx, base, tail_offset); let tail_len = Sub(bcx, len, tail_offset); let tail_ty = ty::mk_evec(bcx.tcx(), ty::mt {ty: vt.unit_ty, mutbl: ast::m_imm}, ty::vstore_slice(ty::re_static) ); let scratch = scratch_datum(bcx, tail_ty, false); Store(bcx, tail_begin, GEPi(bcx, scratch.val, [0u, abi::slice_elt_base]) ); Store(bcx, tail_len, GEPi(bcx, scratch.val, [0u, abi::slice_elt_len]) ); elems.push(scratch.val); scratch.add_clean(bcx); } return {vals: elems, bcx: bcx}; } // NB: This function does not collect fields from struct-like enum variants. pub fn collect_record_or_struct_fields(bcx: block, m: &[@Match], col: uint) -> ~[ast::ident] { let mut fields: ~[ast::ident] = ~[]; for vec::each(m) |br| { match /*bad*/copy br.pats[col].node { ast::pat_rec(fs, _) => extend(&mut fields, fs), ast::pat_struct(_, fs, _) => { match ty::get(node_id_type(bcx, br.pats[col].id)).sty { ty::ty_struct(*) => extend(&mut fields, fs), _ => () } } _ => () } } return fields; fn extend(idents: &mut ~[ast::ident], field_pats: &[ast::field_pat]) { for field_pats.each |field_pat| { let field_ident = field_pat.ident; if !vec::any(*idents, |x| *x == field_ident) { idents.push(field_ident); } } } } pub fn root_pats_as_necessary(bcx: block, m: &[@Match], col: uint, val: ValueRef) -> block { let mut bcx = bcx; for vec::each(m) |br| { let pat_id = br.pats[col].id; let key = root_map_key {id: pat_id, derefs: 0u }; match bcx.ccx().maps.root_map.find(&key) { None => (), Some(root_info) => { // Note: the scope_id will always be the id of the match. See // the extended comment in rustc::middle::borrowck::preserve() // for details (look for the case covering cat_discr). let datum = Datum {val: val, ty: node_id_type(bcx, pat_id), mode: ByRef, source: ZeroMem}; bcx = datum.root(bcx, root_info); // If we kept going, we'd only re-root the same value, so // return now. return bcx; } } } return bcx; } // Macro for deciding whether any of the remaining matches fit a given kind of // pattern. Note that, because the macro is well-typed, either ALL of the // matches should fit that sort of pattern or NONE (however, some of the // matches may be wildcards like _ or identifiers). macro_rules! any_pat ( ($m:expr, $pattern:pat) => ( vec::any($m, |br| { match br.pats[col].node { $pattern => true, _ => false } }) ) ) pub fn any_box_pat(m: &[@Match], col: uint) -> bool { any_pat!(m, ast::pat_box(_)) } pub fn any_uniq_pat(m: &[@Match], col: uint) -> bool { any_pat!(m, ast::pat_uniq(_)) } pub fn any_region_pat(m: &[@Match], col: uint) -> bool { any_pat!(m, ast::pat_region(_)) } pub fn any_tup_pat(m: &[@Match], col: uint) -> bool { any_pat!(m, ast::pat_tup(_)) } pub fn any_tuple_struct_pat(bcx: block, m: &[@Match], col: uint) -> bool { vec::any(m, |br| { let pat = br.pats[col]; match pat.node { ast::pat_enum(_, Some(_)) => { match bcx.tcx().def_map.find(&pat.id) { Some(ast::def_struct(*)) => true, _ => false } } _ => false } }) } pub type mk_fail = fn@() -> BasicBlockRef; pub fn pick_col(m: &[@Match]) -> uint { fn score(p: @ast::pat) -> uint { match p.node { ast::pat_lit(_) | ast::pat_enum(_, _) | ast::pat_range(_, _) => 1u, ast::pat_ident(_, _, Some(p)) => score(p), _ => 0u } } let mut scores = vec::from_elem(m[0].pats.len(), 0u); for vec::each(m) |br| { let mut i = 0u; for vec::each(br.pats) |p| { scores[i] += score(*p); i += 1u; } } let mut max_score = 0u; let mut best_col = 0u; let mut i = 0u; for vec::each(scores) |score| { let score = *score; // Irrefutable columns always go first, they'd only be duplicated in // the branches. if score == 0u { return i; } // If no irrefutable ones are found, we pick the one with the biggest // branching factor. if score > max_score { max_score = score; best_col = i; } i += 1u; } return best_col; } #[deriving_eq] pub enum branch_kind { no_branch, single, switch, compare, compare_vec_len, } // Compiles a comparison between two things. // // NB: This must produce an i1, not a Rust bool (i8). pub fn compare_values(cx: block, lhs: ValueRef, rhs: ValueRef, rhs_t: ty::t) -> Result { let _icx = cx.insn_ctxt("compare_values"); if ty::type_is_scalar(rhs_t) { let rs = compare_scalar_types(cx, lhs, rhs, rhs_t, ast::eq); return rslt(rs.bcx, rs.val); } match ty::get(rhs_t).sty { ty::ty_estr(ty::vstore_uniq) => { let scratch_result = scratch_datum(cx, ty::mk_bool(cx.tcx()), false); let scratch_lhs = alloca(cx, val_ty(lhs)); Store(cx, lhs, scratch_lhs); let scratch_rhs = alloca(cx, val_ty(rhs)); Store(cx, rhs, scratch_rhs); let did = cx.tcx().lang_items.uniq_str_eq_fn(); let bcx = callee::trans_rtcall_or_lang_call(cx, did, ~[scratch_lhs, scratch_rhs], expr::SaveIn( scratch_result.val)); let result = scratch_result.to_result(bcx); Result { bcx: result.bcx, val: bool_to_i1(result.bcx, result.val) } } ty::ty_estr(_) => { let scratch_result = scratch_datum(cx, ty::mk_bool(cx.tcx()), false); let did = cx.tcx().lang_items.str_eq_fn(); let bcx = callee::trans_rtcall_or_lang_call(cx, did, ~[lhs, rhs], expr::SaveIn( scratch_result.val)); let result = scratch_result.to_result(bcx); Result { bcx: result.bcx, val: bool_to_i1(result.bcx, result.val) } } _ => { cx.tcx().sess.bug(~"only scalars and strings supported in \ compare_values"); } } } pub fn store_non_ref_bindings(bcx: block, data: &ArmData, opt_temp_cleanups: Option<&DVec>) -> block { /*! * * For each copy/move binding, copy the value from the value * being matched into its final home. This code executes once * one of the patterns for a given arm has completely matched. * It adds temporary cleanups to the `temp_cleanups` array, * if one is provided. */ let mut bcx = bcx; for data.bindings_map.each_value |&binding_info| { match binding_info.trmode { TrByValue(is_move, lldest) => { let llval = Load(bcx, binding_info.llmatch); // get a T* let datum = Datum {val: llval, ty: binding_info.ty, mode: ByRef, source: ZeroMem}; bcx = { if is_move { datum.move_to(bcx, INIT, lldest) } else { datum.copy_to(bcx, INIT, lldest) } }; for opt_temp_cleanups.each |temp_cleanups| { add_clean_temp_mem(bcx, lldest, binding_info.ty); temp_cleanups.push(lldest); } } TrByRef | TrByImplicitRef => {} } } return bcx; } pub fn insert_lllocals(bcx: block, data: &ArmData, add_cleans: bool) -> block { /*! * * For each binding in `data.bindings_map`, adds an appropriate entry into * the `fcx.lllocals` map. If add_cleans is true, then adds cleanups for * the bindings. */ for data.bindings_map.each_value |&binding_info| { let llval = match binding_info.trmode { // By value bindings: use the stack slot that we // copied/moved the value into TrByValue(_, lldest) => { if add_cleans { add_clean(bcx, lldest, binding_info.ty); } lldest } // By ref binding: use the ptr into the matched value TrByRef => { binding_info.llmatch } // Ugly: for implicit ref, we actually want a T*, but // we have a T**, so we had to load. This will go away // once implicit refs go away. TrByImplicitRef => { Load(bcx, binding_info.llmatch) } }; bcx.fcx.lllocals.insert(binding_info.id, local_mem(llval)); } return bcx; } pub fn compile_guard(bcx: block, guard_expr: @ast::expr, data: &ArmData, m: &[@Match], vals: &[ValueRef], chk: Option) -> block { debug!("compile_guard(bcx=%s, guard_expr=%s, m=%s, vals=%?)", bcx.to_str(), bcx.expr_to_str(guard_expr), matches_to_str(bcx, m), vals.map(|v| bcx.val_str(*v))); let _indenter = indenter(); let mut bcx = bcx; let temp_cleanups = DVec(); bcx = store_non_ref_bindings(bcx, data, Some(&temp_cleanups)); bcx = insert_lllocals(bcx, data, false); let val = unpack_result!(bcx, { do with_scope_result(bcx, guard_expr.info(), ~"guard") |bcx| { expr::trans_to_datum(bcx, guard_expr).to_result() } }); let val = bool_to_i1(bcx, val); // Revoke the temp cleanups now that the guard successfully executed. for temp_cleanups.each |llval| { revoke_clean(bcx, *llval); } return do with_cond(bcx, Not(bcx, val)) |bcx| { // Guard does not match: free the values we copied, // and remove all bindings from the lllocals table let bcx = drop_bindings(bcx, data); compile_submatch(bcx, m, vals, chk); bcx }; fn drop_bindings(bcx: block, data: &ArmData) -> block { let mut bcx = bcx; for data.bindings_map.each_value |&binding_info| { match binding_info.trmode { TrByValue(_, llval) => { bcx = glue::drop_ty(bcx, llval, binding_info.ty); } TrByRef | TrByImplicitRef => {} } bcx.fcx.lllocals.remove(&binding_info.id); } return bcx; } } pub fn compile_submatch(bcx: block, m: &[@Match], vals: &[ValueRef], chk: Option) { debug!("compile_submatch(bcx=%s, m=%s, vals=%?)", bcx.to_str(), matches_to_str(bcx, m), vals.map(|v| bcx.val_str(*v))); let _indenter = indenter(); /* For an empty match, a fall-through case must exist */ assert(m.len() > 0u || chk.is_some()); let _icx = bcx.insn_ctxt("match::compile_submatch"); let mut bcx = bcx; let tcx = bcx.tcx(), dm = tcx.def_map; if m.len() == 0u { Br(bcx, chk.get()()); return; } if m[0].pats.len() == 0u { let data = m[0].data; match data.arm.guard { Some(guard_expr) => { bcx = compile_guard(bcx, guard_expr, m[0].data, vec::slice(m, 1, m.len()), vals, chk); } _ => () } Br(bcx, data.bodycx.llbb); return; } let col = pick_col(m); let val = vals[col]; let m = { if has_nested_bindings(m, col) { expand_nested_bindings(bcx, m, col, val) } else { m.to_vec() } }; let vals_left = vec::append(vec::slice(vals, 0u, col).to_vec(), vec::slice(vals, col + 1u, vals.len())); let ccx = bcx.fcx.ccx; let mut pat_id = 0; for vec::each(m) |br| { // Find a real id (we're adding placeholder wildcard patterns, but // each column is guaranteed to have at least one real pattern) if pat_id == 0 { pat_id = br.pats[col].id; } } bcx = root_pats_as_necessary(bcx, m, col, val); let rec_fields = collect_record_or_struct_fields(bcx, m, col); if rec_fields.len() > 0 { let pat_ty = node_id_type(bcx, pat_id); do expr::with_field_tys(tcx, pat_ty, None) |_has_dtor, field_tys| { let rec_vals = rec_fields.map(|field_name| { let ix = ty::field_idx_strict(tcx, *field_name, field_tys); GEPi(bcx, val, struct_field(ix)) }); compile_submatch( bcx, enter_rec_or_struct(bcx, dm, m, col, rec_fields, val), vec::append(rec_vals, vals_left), chk); } return; } if any_tup_pat(m, col) { let tup_ty = node_id_type(bcx, pat_id); let n_tup_elts = match /*bad*/copy ty::get(tup_ty).sty { ty::ty_tup(elts) => elts.len(), _ => ccx.sess.bug(~"non-tuple type in tuple pattern") }; let tup_vals = vec::from_fn(n_tup_elts, |i| GEPi(bcx, val, [0u, i])); compile_submatch(bcx, enter_tup(bcx, dm, m, col, val, n_tup_elts), vec::append(tup_vals, vals_left), chk); return; } if any_tuple_struct_pat(bcx, m, col) { let struct_ty = node_id_type(bcx, pat_id); let struct_element_count; match ty::get(struct_ty).sty { ty::ty_struct(struct_id, _) => { struct_element_count = ty::lookup_struct_fields(tcx, struct_id).len(); } _ => { ccx.sess.bug(~"non-struct type in tuple struct pattern"); } } let llstructvals = vec::from_fn( struct_element_count, |i| GEPi(bcx, val, struct_field(i))); compile_submatch(bcx, enter_tuple_struct(bcx, dm, m, col, val, struct_element_count), vec::append(llstructvals, vals_left), chk); return; } // Unbox in case of a box field if any_box_pat(m, col) { let llbox = Load(bcx, val); let box_no_addrspace = non_gc_box_cast(bcx, llbox); let unboxed = GEPi(bcx, box_no_addrspace, [0u, abi::box_field_body]); compile_submatch(bcx, enter_box(bcx, dm, m, col, val), vec::append(~[unboxed], vals_left), chk); return; } if any_uniq_pat(m, col) { let llbox = Load(bcx, val); let box_no_addrspace = non_gc_box_cast(bcx, llbox); let unboxed = GEPi(bcx, box_no_addrspace, [0u, abi::box_field_body]); compile_submatch(bcx, enter_uniq(bcx, dm, m, col, val), vec::append(~[unboxed], vals_left), chk); return; } if any_region_pat(m, col) { let loaded_val = Load(bcx, val); compile_submatch(bcx, enter_region(bcx, dm, m, col, val), vec::append(~[loaded_val], vals_left), chk); return; } // Decide what kind of branch we need let opts = get_options(ccx, m, col); let mut kind = no_branch; let mut test_val = val; if opts.len() > 0u { match opts[0] { var(_, vdef) => { let variants = ty::enum_variants(tcx, vdef.enm); if variants.len() == 1 { kind = single; } else { let enumptr = PointerCast(bcx, val, T_opaque_enum_ptr(ccx)); let discrimptr = GEPi(bcx, enumptr, [0u, 0u]); assert variants.len() > 1; let min_discrim = do variants.foldr(0) |&x, y| { int::min(x.disr_val, y) }; let max_discrim = do variants.foldr(0) |&x, y| { int::max(x.disr_val, y) }; test_val = LoadRangeAssert(bcx, discrimptr, min_discrim as c_ulonglong, (max_discrim + 1) as c_ulonglong, lib::llvm::True); kind = switch; } } lit(_) => { let pty = node_id_type(bcx, pat_id); test_val = load_if_immediate(bcx, val, pty); kind = if ty::type_is_integral(pty) { switch } else { compare }; } range(_, _) => { test_val = Load(bcx, val); kind = compare; }, vec_len_eq(_) | vec_len_ge(_) => { let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id)); let unboxed = load_if_immediate(bcx, val, vt.vec_ty); let (_, len) = tvec::get_base_and_len( bcx, unboxed, vt.vec_ty ); test_val = SDiv(bcx, len, vt.llunit_size); kind = compare_vec_len; } } } for vec::each(opts) |o| { match *o { range(_, _) => { kind = compare; break } _ => () } } let else_cx = match kind { no_branch | single => bcx, _ => sub_block(bcx, ~"match_else") }; let sw = if kind == switch { Switch(bcx, test_val, else_cx.llbb, opts.len()) } else { C_int(ccx, 0) // Placeholder for when not using a switch }; let defaults = enter_default(else_cx, dm, m, col, val); let exhaustive = chk.is_none() && defaults.len() == 0u; let len = opts.len(); let mut i = 0u; // Compile subtrees for each option for vec::each(opts) |opt| { i += 1u; let mut opt_cx = else_cx; if !exhaustive || i < len { opt_cx = sub_block(bcx, ~"match_case"); match kind { single => Br(bcx, opt_cx.llbb), switch => { match trans_opt(bcx, opt) { single_result(r) => { unsafe { llvm::LLVMAddCase(sw, r.val, opt_cx.llbb); bcx = r.bcx; } } _ => { bcx.sess().bug( ~"in compile_submatch, expected \ trans_opt to return a single_result") } } } compare => { let t = node_id_type(bcx, pat_id); let Result {bcx: after_cx, val: matches} = { do with_scope_result(bcx, None, ~"compare_scope") |bcx| { match trans_opt(bcx, opt) { single_result( Result {bcx, val}) => { compare_values(bcx, test_val, val, t) } lower_bound( Result {bcx, val}) => { compare_scalar_types( bcx, test_val, val, t, ast::ge) } range_result( Result {val: vbegin, _}, Result {bcx, val: vend}) => { let Result {bcx, val: llge} = compare_scalar_types( bcx, test_val, vbegin, t, ast::ge); let Result {bcx, val: llle} = compare_scalar_types( bcx, test_val, vend, t, ast::le); rslt(bcx, And(bcx, llge, llle)) } } } }; bcx = sub_block(after_cx, ~"compare_next"); CondBr(after_cx, matches, opt_cx.llbb, bcx.llbb); } compare_vec_len => { let Result {bcx: after_cx, val: matches} = { do with_scope_result(bcx, None, ~"compare_vec_len_scope") |bcx| { match trans_opt(bcx, opt) { single_result( Result {bcx, val}) => { let value = compare_scalar_values( bcx, test_val, val, signed_int, ast::eq); rslt(bcx, value) } lower_bound( Result {bcx, val: val}) => { let value = compare_scalar_values( bcx, test_val, val, signed_int, ast::ge); rslt(bcx, value) } range_result( Result {val: vbegin, _}, Result {bcx, val: vend}) => { let llge = compare_scalar_values( bcx, test_val, vbegin, signed_int, ast::ge); let llle = compare_scalar_values( bcx, test_val, vend, signed_int, ast::le); rslt(bcx, And(bcx, llge, llle)) } } } }; bcx = sub_block(after_cx, ~"compare_vec_len_next"); CondBr(after_cx, matches, opt_cx.llbb, bcx.llbb); } _ => () } } else if kind == compare || kind == compare_vec_len { Br(bcx, else_cx.llbb); } let mut size = 0u; let mut unpacked = ~[]; match *opt { var(_, vdef) => { let args = extract_variant_args(opt_cx, pat_id, vdef, val); size = args.vals.len(); unpacked = /*bad*/copy args.vals; opt_cx = args.bcx; } vec_len_eq(n) | vec_len_ge(n) => { let tail = match *opt { vec_len_ge(_) => true, _ => false }; let args = extract_vec_elems(opt_cx, pat_id, n, tail, val); size = args.vals.len(); unpacked = /*bad*/copy args.vals; opt_cx = args.bcx; } lit(_) | range(_, _) => () } let opt_ms = enter_opt(opt_cx, m, opt, col, size, val); let opt_vals = vec::append(unpacked, vals_left); compile_submatch(opt_cx, opt_ms, opt_vals, chk); } // Compile the fall-through case, if any if !exhaustive { if kind == compare || kind == compare_vec_len { Br(bcx, else_cx.llbb); } if kind != single { compile_submatch(else_cx, defaults, vals_left, chk); } } } pub fn trans_match(bcx: block, match_expr: @ast::expr, discr_expr: @ast::expr, arms: ~[ast::arm], dest: Dest) -> block { let _icx = bcx.insn_ctxt("match::trans_match"); do with_scope(bcx, match_expr.info(), ~"match") |bcx| { trans_match_inner(bcx, discr_expr, arms, dest) } } pub fn trans_match_inner(scope_cx: block, discr_expr: @ast::expr, arms: &[ast::arm], dest: Dest) -> block { let _icx = scope_cx.insn_ctxt("match::trans_match_inner"); let mut bcx = scope_cx; let tcx = bcx.tcx(); let discr_datum = unpack_datum!(bcx, { expr::trans_to_datum(bcx, discr_expr) }); if bcx.unreachable { return bcx; } let mut arm_datas = ~[], matches = ~[]; for vec::each(arms) |arm| { let body = scope_block(bcx, arm.body.info(), ~"case_body"); // Create the bindings map, which is a mapping from each binding name // to an alloca() that will be the value for that local variable. // Note that we use the names because each binding will have many ids // from the various alternatives. let bindings_map = HashMap(); do pat_bindings(tcx.def_map, arm.pats[0]) |bm, p_id, _s, path| { let ident = path_to_ident(path); let variable_ty = node_id_type(bcx, p_id); let llvariable_ty = type_of::type_of(bcx.ccx(), variable_ty); let llmatch, trmode; match bm { ast::bind_by_copy | ast::bind_infer => { // in this case, the final type of the variable will be T, // but during matching we need to store a *T as explained // above let is_move = scope_cx.ccx().maps.moves_map.contains_key(&p_id); llmatch = alloca(bcx, T_ptr(llvariable_ty)); trmode = TrByValue(is_move, alloca(bcx, llvariable_ty)); } ast::bind_by_ref(_) => { llmatch = alloca(bcx, llvariable_ty); trmode = TrByRef; } }; bindings_map.insert(ident, BindingInfo { llmatch: llmatch, trmode: trmode, id: p_id, ty: variable_ty }); } let arm_data = @ArmData {bodycx: body, arm: arm, bindings_map: bindings_map}; arm_datas.push(arm_data); for vec::each(arm.pats) |p| { matches.push(@Match {pats: ~[*p], data: arm_data}); } } let t = node_id_type(bcx, discr_expr.id); let chk = { if ty::type_is_empty(tcx, t) { // Special case for empty types let fail_cx = @mut None; let f: mk_fail = || mk_fail(scope_cx, discr_expr.span, ~"scrutinizing value that can't exist", fail_cx); Some(f) } else { None } }; let lldiscr = discr_datum.to_ref_llval(bcx); compile_submatch(bcx, matches, ~[lldiscr], chk); let arm_cxs = DVec(); for arm_datas.each |arm_data| { let mut bcx = arm_data.bodycx; // If this arm has a guard, then the various by-value bindings have // already been copied into their homes. If not, we do it here. This // is just to reduce code space. See extensive comment at the start // of the file for more details. if arm_data.arm.guard.is_none() { bcx = store_non_ref_bindings(bcx, *arm_data, None); } // insert bindings into the lllocals map and add cleanups bcx = insert_lllocals(bcx, *arm_data, true); bcx = controlflow::trans_block(bcx, &arm_data.arm.body, dest); bcx = trans_block_cleanups(bcx, block_cleanups(arm_data.bodycx)); arm_cxs.push(bcx); } bcx = controlflow::join_blocks(scope_cx, dvec::unwrap(arm_cxs)); return bcx; fn mk_fail(bcx: block, sp: span, +msg: ~str, finished: @mut Option) -> BasicBlockRef { match *finished { Some(bb) => return bb, _ => () } let fail_cx = sub_block(bcx, ~"case_fallthrough"); controlflow::trans_fail(fail_cx, Some(sp), msg); *finished = Some(fail_cx.llbb); return fail_cx.llbb; } } pub enum IrrefutablePatternBindingMode { // Stores the association between node ID and LLVM value in `lllocals`. BindLocal, // Stores the association between node ID and LLVM value in `llargs`. BindArgument } // Not match-related, but similar to the pattern-munging code above pub fn bind_irrefutable_pat(bcx: block, pat: @ast::pat, val: ValueRef, make_copy: bool, binding_mode: IrrefutablePatternBindingMode) -> block { let _icx = bcx.insn_ctxt("match::bind_irrefutable_pat"); let ccx = bcx.fcx.ccx; let mut bcx = bcx; // Necessary since bind_irrefutable_pat is called outside trans_match match /*bad*/copy pat.node { ast::pat_ident(_, _,inner) => { if pat_is_variant_or_struct(bcx.tcx().def_map, pat) { return bcx; } if make_copy { let binding_ty = node_id_type(bcx, pat.id); let datum = Datum {val: val, ty: binding_ty, mode: ByRef, source: RevokeClean}; let scratch = scratch_datum(bcx, binding_ty, false); datum.copy_to_datum(bcx, INIT, scratch); match binding_mode { BindLocal => { bcx.fcx.lllocals.insert(pat.id, local_mem(scratch.val)); } BindArgument => { bcx.fcx.llargs.insert(pat.id, local_mem(scratch.val)); } } add_clean(bcx, scratch.val, binding_ty); } else { match binding_mode { BindLocal => { bcx.fcx.lllocals.insert(pat.id, local_mem(val)); } BindArgument => { bcx.fcx.llargs.insert(pat.id, local_mem(val)); } } } for inner.each |inner_pat| { bcx = bind_irrefutable_pat( bcx, *inner_pat, val, true, binding_mode); } } ast::pat_enum(_, sub_pats) => { match bcx.tcx().def_map.find(&pat.id) { Some(ast::def_variant(*)) => { let pat_def = ccx.tcx.def_map.get(&pat.id); let vdefs = ast_util::variant_def_ids(pat_def); let args = extract_variant_args(bcx, pat.id, vdefs, val); for sub_pats.each |sub_pat| { for vec::eachi(args.vals) |i, argval| { bcx = bind_irrefutable_pat(bcx, sub_pat[i], *argval, make_copy, binding_mode); } } } Some(ast::def_struct(*)) => { match sub_pats { None => { // This is a unit-like struct. Nothing to do here. } Some(elems) => { // This is the tuple variant case. for vec::eachi(elems) |i, elem| { let fldptr = GEPi(bcx, val, struct_field(i)); bcx = bind_irrefutable_pat(bcx, *elem, fldptr, make_copy, binding_mode); } } } } _ => { // Nothing to do here. } } } ast::pat_rec(fields, _) | ast::pat_struct(_, fields, _) => { let tcx = bcx.tcx(); let pat_ty = node_id_type(bcx, pat.id); do expr::with_field_tys(tcx, pat_ty, None) |_hd, field_tys| { for vec::each(fields) |f| { let ix = ty::field_idx_strict(tcx, f.ident, field_tys); let fldptr = GEPi(bcx, val, struct_field(ix)); bcx = bind_irrefutable_pat(bcx, f.pat, fldptr, make_copy, binding_mode); } } } ast::pat_tup(elems) => { for vec::eachi(elems) |i, elem| { let fldptr = GEPi(bcx, val, [0u, i]); bcx = bind_irrefutable_pat(bcx, *elem, fldptr, make_copy, binding_mode); } } ast::pat_box(inner) | ast::pat_uniq(inner) => { let llbox = Load(bcx, val); let unboxed = GEPi(bcx, llbox, [0u, abi::box_field_body]); bcx = bind_irrefutable_pat(bcx, inner, unboxed, true, binding_mode); } ast::pat_region(inner) => { let loaded_val = Load(bcx, val); bcx = bind_irrefutable_pat(bcx, inner, loaded_val, true, binding_mode); } ast::pat_wild | ast::pat_lit(_) | ast::pat_range(_, _) | ast::pat_vec(*) => () } return bcx; } // Local Variables: // mode: rust // fill-column: 78; // indent-tabs-mode: nil // c-basic-offset: 4 // buffer-file-coding-system: utf-8-unix // End: