import std::{str, vec, option}; import option::{some, none}; import std::map::hashmap; import lib::llvm::llvm; import lib::llvm::llvm::{ValueRef, TypeRef, BasicBlockRef}; import trans_build::*; import trans::{new_sub_block_ctxt, new_scope_block_ctxt, load_if_immediate}; import ty::pat_ty; import syntax::ast; import syntax::ast_util; import syntax::ast_util::dummy_sp; import syntax::ast::def_id; import syntax::codemap::span; import util::common::lit_eq; import trans_common::*; // An option identifying a branch (either a literal or a tag variant) tag opt { lit(@ast::lit); var(/* variant id */uint, /* variant dids */{tg: def_id, var: def_id}); } fn opt_eq(a: opt, b: opt) -> bool { alt a { lit(la) { ret alt b { lit(lb) { lit_eq(la, lb) } var(_, _) { false } }; } var(ida, _) { ret alt b { lit(_) { false } var(idb, _) { ida == idb } }; } } } fn trans_opt(bcx: @block_ctxt, o: opt) -> result { alt o { lit(l) { alt l.node { ast::lit_str(s) { let strty = ty::mk_str(bcx_tcx(bcx)); let {bcx, val: dst} = trans::alloc_ty(bcx, strty); bcx = trans_vec::trans_str(bcx, s, trans::save_in(dst)); add_clean_temp(bcx, dst, strty); ret rslt(bcx, dst); } _ { ret rslt(bcx, trans::trans_crate_lit(bcx_ccx(bcx), *l)); } } } var(id, _) { ret rslt(bcx, C_int(id as int)); } } } fn variant_opt(ccx: @crate_ctxt, pat_id: ast::node_id) -> opt { let vdef = ast_util::variant_def_ids(ccx.tcx.def_map.get(pat_id)); let variants = ty::tag_variants(ccx.tcx, vdef.tg); let i = 0u; for v: ty::variant_info in variants { if vdef.var == v.id { ret var(i, vdef); } i += 1u; } fail; } type bind_map = [{ident: ast::ident, val: ValueRef}]; fn assoc(key: str, list: bind_map) -> option::t { for elt: {ident: ast::ident, val: ValueRef} in list { if str::eq(elt.ident, key) { ret some(elt.val); } } ret none; } type match_branch = @{pats: [@ast::pat], bound: bind_map, data: @{body: BasicBlockRef, guard: option::t<@ast::expr>, id_map: ast_util::pat_id_map}}; type match = [match_branch]; fn matches_always(p: @ast::pat) -> bool { ret alt p.node { ast::pat_wild. { true } ast::pat_bind(_) { true } ast::pat_rec(_, _) { true } ast::pat_tup(_) { true } _ { false } }; } type enter_pat = fn(@ast::pat) -> option::t<[@ast::pat]>; fn enter_match(m: match, col: uint, val: ValueRef, e: enter_pat) -> match { let result = []; for br: match_branch in m { alt e(br.pats[col]) { some(sub) { let pats = vec::slice(br.pats, 0u, col) + sub + vec::slice(br.pats, col + 1u, vec::len(br.pats)); let new_br = @{pats: pats, bound: alt br.pats[col].node { ast::pat_bind(name) { br.bound + [{ident: name, val: val}] } _ { br.bound } } with *br}; result += [new_br]; } none. { } } } ret result; } fn enter_default(m: match, col: uint, val: ValueRef) -> match { fn e(p: @ast::pat) -> option::t<[@ast::pat]> { ret if matches_always(p) { some([]) } else { none }; } ret enter_match(m, col, val, e); } fn enter_opt(ccx: @crate_ctxt, m: match, opt: opt, col: uint, tag_size: uint, val: ValueRef) -> match { let dummy = @{id: 0, node: ast::pat_wild, span: dummy_sp()}; fn e(ccx: @crate_ctxt, dummy: @ast::pat, opt: opt, size: uint, p: @ast::pat) -> option::t<[@ast::pat]> { alt p.node { ast::pat_tag(ctor, subpats) { ret if opt_eq(variant_opt(ccx, p.id), opt) { some(subpats) } else { none }; } ast::pat_lit(l) { ret if opt_eq(lit(l), opt) { some([]) } else { none }; } _ { ret some(vec::init_elt(dummy, size)); } } } ret enter_match(m, col, val, bind e(ccx, dummy, opt, tag_size, _)); } fn enter_rec(m: match, col: uint, fields: [ast::ident], val: ValueRef) -> match { let dummy = @{id: 0, node: ast::pat_wild, span: dummy_sp()}; fn e(dummy: @ast::pat, fields: [ast::ident], p: @ast::pat) -> option::t<[@ast::pat]> { alt p.node { ast::pat_rec(fpats, _) { let pats = []; for fname: ast::ident in fields { let pat = dummy; for fpat: ast::field_pat in fpats { if str::eq(fpat.ident, fname) { pat = fpat.pat; break; } } pats += [pat]; } ret some(pats); } _ { ret some(vec::init_elt(dummy, vec::len(fields))); } } } ret enter_match(m, col, val, bind e(dummy, fields, _)); } fn enter_tup(m: match, col: uint, val: ValueRef, n_elts: uint) -> match { let dummy = @{id: 0, node: ast::pat_wild, span: dummy_sp()}; fn e(dummy: @ast::pat, n_elts: uint, p: @ast::pat) -> option::t<[@ast::pat]> { alt p.node { ast::pat_tup(elts) { ret some(elts); } _ { ret some(vec::init_elt(dummy, n_elts)); } } } ret enter_match(m, col, val, bind e(dummy, n_elts, _)); } fn enter_box(m: match, col: uint, val: ValueRef) -> match { let dummy = @{id: 0, node: ast::pat_wild, span: dummy_sp()}; fn e(dummy: @ast::pat, p: @ast::pat) -> option::t<[@ast::pat]> { alt p.node { ast::pat_box(sub) { ret some([sub]); } _ { ret some([dummy]); } } } ret enter_match(m, col, val, bind e(dummy, _)); } fn enter_uniq(m: match, col: uint, val: ValueRef) -> match { let dummy = @{id: 0, node: ast::pat_wild, span: dummy_sp()}; fn e(dummy: @ast::pat, p: @ast::pat) -> option::t<[@ast::pat]> { alt p.node { ast::pat_uniq(sub) { ret some([sub]); } _ { ret some([dummy]); } } } ret enter_match(m, col, val, bind e(dummy, _)); } fn get_options(ccx: @crate_ctxt, m: match, col: uint) -> [opt] { fn add_to_set(&set: [opt], val: opt) { for l: opt in set { if opt_eq(l, val) { ret; } } set += [val]; } let found = []; for br: match_branch in m { alt br.pats[col].node { ast::pat_lit(l) { add_to_set(found, lit(l)); } ast::pat_tag(_, _) { add_to_set(found, variant_opt(ccx, br.pats[col].id)); } _ { } } } ret found; } fn extract_variant_args(bcx: @block_ctxt, pat_id: ast::node_id, vdefs: {tg: def_id, var: def_id}, val: ValueRef) -> {vals: [ValueRef], bcx: @block_ctxt} { let ccx = bcx.fcx.lcx.ccx; let ty_param_substs = ty::node_id_to_type_params(ccx.tcx, pat_id); let blobptr = val; let variants = ty::tag_variants(ccx.tcx, vdefs.tg); let args = []; let size = vec::len(ty::tag_variant_with_id(ccx.tcx, vdefs.tg, vdefs.var).args); if size > 0u && vec::len(variants) != 1u { let tagptr = PointerCast(bcx, val, trans_common::T_opaque_tag_ptr(ccx.tn)); blobptr = GEP(bcx, tagptr, [C_int(0), C_int(1)]); } let i = 0u; let vdefs_tg = vdefs.tg; let vdefs_var = vdefs.var; while i < size { check (valid_variant_index(i, bcx, vdefs_tg, vdefs_var)); let r = trans::GEP_tag(bcx, blobptr, vdefs_tg, vdefs_var, ty_param_substs, i); bcx = r.bcx; args += [r.val]; i += 1u; } ret {vals: args, bcx: bcx}; } fn collect_record_fields(m: match, col: uint) -> [ast::ident] { let fields = []; for br: match_branch in m { alt br.pats[col].node { ast::pat_rec(fs, _) { for f: ast::field_pat in fs { if !vec::any(bind str::eq(f.ident, _), fields) { fields += [f.ident]; } } } _ { } } } ret fields; } fn any_box_pat(m: match, col: uint) -> bool { for br: match_branch in m { alt br.pats[col].node { ast::pat_box(_) { ret true; } _ { } } } ret false; } fn any_uniq_pat(m: match, col: uint) -> bool { for br: match_branch in m { alt br.pats[col].node { ast::pat_uniq(_) { ret true; } _ { } } } ret false; } fn any_tup_pat(m: match, col: uint) -> bool { for br: match_branch in m { alt br.pats[col].node { ast::pat_tup(_) { ret true; } _ { } } } ret false; } type exit_node = {bound: bind_map, from: BasicBlockRef, to: BasicBlockRef}; type mk_fail = fn() -> BasicBlockRef; fn pick_col(m: match) -> uint { let scores = vec::init_elt_mut(0u, vec::len(m[0].pats)); for br: match_branch in m { let i = 0u; for p: @ast::pat in br.pats { alt p.node { ast::pat_lit(_) | ast::pat_tag(_, _) { scores[i] += 1u; } _ { } } i += 1u; } } let max_score = 0u; let best_col = 0u; let i = 0u; for score: uint in scores { // Irrefutable columns always go first, they'd only be duplicated in // the branches. if score == 0u { ret 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; } ret best_col; } fn compile_submatch(bcx: @block_ctxt, m: match, vals: [ValueRef], f: mk_fail, &exits: [exit_node]) { if vec::len(m) == 0u { Br(bcx, f()); ret; } if vec::len(m[0].pats) == 0u { let data = m[0].data; alt data.guard { some(e) { let guard_cx = new_scope_block_ctxt(bcx, "submatch_guard"); Br(bcx, guard_cx.llbb); // Temporarily set bindings. They'll be rewritten to PHI nodes for // the actual arm block. for each @{key: key, val: val} in data.id_map.items() { bcx.fcx.lllocals.insert(val, option::get(assoc(key, m[0].bound))); } let {bcx: guard_bcx, val: guard_val} = trans::trans_expr(guard_cx, e); guard_bcx = trans::trans_block_cleanups(guard_bcx, guard_cx); let next_cx = new_sub_block_ctxt(guard_cx, "submatch_next"); let else_cx = new_sub_block_ctxt(guard_cx, "submatch_else"); CondBr(guard_bcx, guard_val, next_cx.llbb, else_cx.llbb); compile_submatch(else_cx, vec::slice(m, 1u, vec::len(m)), vals, f, exits); bcx = next_cx; } _ { } } if !bcx.unreachable { exits += [{bound: m[0].bound, from: bcx.llbb, to: data.body}]; } Br(bcx, data.body); ret; } let col = pick_col(m); let val = vals[col]; let vals_left = vec::slice(vals, 0u, col) + vec::slice(vals, col + 1u, vec::len(vals)); let ccx = bcx.fcx.lcx.ccx; let pat_id = 0; for br: match_branch in m { // 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; } } let rec_fields = collect_record_fields(m, col); // Separate path for extracting and binding record fields if vec::len(rec_fields) > 0u { let rec_ty = ty::node_id_to_monotype(ccx.tcx, pat_id); let fields = alt ty::struct(ccx.tcx, rec_ty) { ty::ty_rec(fields) { fields } }; let rec_vals = []; for field_name: ast::ident in rec_fields { let ix: uint = ty::field_idx(ccx.sess, dummy_sp(), field_name, fields); // not sure how to get rid of this check check type_is_tup_like(bcx, rec_ty); let r = trans::GEP_tup_like(bcx, rec_ty, val, [0, ix as int]); rec_vals += [r.val]; bcx = r.bcx; } compile_submatch(bcx, enter_rec(m, col, rec_fields, val), rec_vals + vals_left, f, exits); ret; } if any_tup_pat(m, col) { let tup_ty = ty::node_id_to_monotype(ccx.tcx, pat_id); let n_tup_elts = alt ty::struct(ccx.tcx, tup_ty) { ty::ty_tup(elts) { vec::len(elts) } }; let tup_vals = [], i = 0u; while i < n_tup_elts { // how to get rid of this check? check type_is_tup_like(bcx, tup_ty); let r = trans::GEP_tup_like(bcx, tup_ty, val, [0, i as int]); tup_vals += [r.val]; bcx = r.bcx; i += 1u; } compile_submatch(bcx, enter_tup(m, col, val, n_tup_elts), tup_vals + vals_left, f, exits); ret; } // Unbox in case of a box field if any_box_pat(m, col) { let box = Load(bcx, val); let unboxed = InBoundsGEP(bcx, box, [C_int(0), C_int(back::abi::box_rc_field_body)]); compile_submatch(bcx, enter_box(m, col, val), [unboxed] + vals_left, f, exits); ret; } if any_uniq_pat(m, col) { let unboxed = Load(bcx, val); compile_submatch(bcx, enter_uniq(m, col, val), [unboxed] + vals_left, f, exits); ret; } // Decide what kind of branch we need let opts = get_options(ccx, m, col); tag branch_kind { no_branch; single; switch; compare; } let kind = no_branch; let test_val = val; if vec::len(opts) > 0u { alt opts[0] { var(_, vdef) { if vec::len(ty::tag_variants(ccx.tcx, vdef.tg)) == 1u { kind = single; } else { let tagptr = PointerCast(bcx, val, trans_common::T_opaque_tag_ptr(ccx.tn)); let discrimptr = GEP(bcx, tagptr, [C_int(0), C_int(0)]); test_val = Load(bcx, discrimptr); kind = switch; } } lit(l) { kind = alt l.node { ast::lit_str(_) { compare } _ { test_val = Load(bcx, val); switch } }; } } } let else_cx = alt kind { no_branch. | single. { bcx } _ { new_sub_block_ctxt(bcx, "match_else") } }; let sw; if kind == switch { sw = Switch(bcx, test_val, else_cx.llbb, vec::len(opts)); // FIXME This statement is purely here as a work-around for a bug that // I expect to be the same as issue #951. If I remove it, sw ends up // holding a corrupted value (when the compiler is optimized). // This can be removed after our next LLVM upgrade. val_ty(sw); } else { sw = C_int(0); } // Placeholder for when not using a switch // Compile subtrees for each option for opt: opt in opts { let opt_cx = new_sub_block_ctxt(bcx, "match_case"); alt kind { single. { Br(bcx, opt_cx.llbb); } switch. { let r = trans_opt(bcx, opt); bcx = r.bcx; AddCase(sw, r.val, opt_cx.llbb); } compare. { let compare_cx = new_scope_block_ctxt(bcx, "compare_scope"); Br(bcx, compare_cx.llbb); bcx = compare_cx; let r = trans_opt(bcx, opt); bcx = r.bcx; let t = ty::node_id_to_type(ccx.tcx, pat_id); let eq = trans::trans_compare(bcx, ast::eq, test_val, t, r.val, t); let cleanup_cx = trans::trans_block_cleanups(bcx, compare_cx); bcx = new_sub_block_ctxt(bcx, "compare_next"); CondBr(cleanup_cx, eq.val, opt_cx.llbb, bcx.llbb); } _ { } } let size = 0u; let unpacked = []; alt opt { var(_, vdef) { let args = extract_variant_args(opt_cx, pat_id, vdef, val); size = vec::len(args.vals); unpacked = args.vals; opt_cx = args.bcx; } lit(_) { } } compile_submatch(opt_cx, enter_opt(ccx, m, opt, col, size, val), unpacked + vals_left, f, exits); } // Compile the fall-through case if kind == compare { Br(bcx, else_cx.llbb); } if kind != single { compile_submatch(else_cx, enter_default(m, col, val), vals_left, f, exits); } } // Returns false for unreachable blocks fn make_phi_bindings(bcx: @block_ctxt, map: [exit_node], ids: ast_util::pat_id_map) -> bool { let our_block = bcx.llbb as uint; let success = true; for each @{key: name, val: node_id} in ids.items() { let llbbs = []; let vals = []; for ex: exit_node in map { if ex.to as uint == our_block { alt assoc(name, ex.bound) { some(val) { llbbs += [ex.from]; vals += [val]; } none. { } } } } if vec::len(vals) > 0u { let local = Phi(bcx, val_ty(vals[0]), vals, llbbs); bcx.fcx.lllocals.insert(node_id, local); } else { success = false; } } if success { // Copy references that the alias analysis considered unsafe for each @{val: node_id, _} in ids.items() { if bcx_ccx(bcx).copy_map.contains_key(node_id) { let local = bcx.fcx.lllocals.get(node_id); let e_ty = ty::node_id_to_type(bcx_tcx(bcx), node_id); let {bcx: abcx, val: alloc} = trans::alloc_ty(bcx, e_ty); bcx = trans::copy_val(abcx, trans::INIT, alloc, load_if_immediate(abcx, local, e_ty), e_ty); add_clean(bcx, alloc, e_ty); bcx.fcx.lllocals.insert(node_id, alloc); } } } else { Unreachable(bcx); } ret success; } fn trans_alt(cx: @block_ctxt, expr: @ast::expr, arms: [ast::arm], dest: trans::dest) -> @block_ctxt { let bodies = []; let match: match = []; let er = trans::trans_expr(cx, expr); if er.bcx.unreachable { ret er.bcx; } for a: ast::arm in arms { let body = new_scope_block_ctxt(er.bcx, "case_body"); let id_map = ast_util::pat_id_map(a.pats[0]); bodies += [body]; for p: @ast::pat in a.pats { match += [@{pats: [p], bound: [], data: @{body: body.llbb, guard: a.guard, id_map: id_map}}]; } } // Cached fail-on-fallthrough block let fail_cx = @mutable none; fn mk_fail(cx: @block_ctxt, sp: span, done: @mutable option::t) -> BasicBlockRef { alt *done { some(bb) { ret bb; } _ { } } let fail_cx = new_sub_block_ctxt(cx, "case_fallthrough"); trans::trans_fail(fail_cx, some(sp), "non-exhaustive match failure");; *done = some(fail_cx.llbb); ret fail_cx.llbb; } let exit_map = []; let t = trans::node_id_type(cx.fcx.lcx.ccx, expr.id); let vr = trans::spill_if_immediate(er.bcx, er.val, t); compile_submatch(vr.bcx, match, [vr.val], bind mk_fail(cx, expr.span, fail_cx), exit_map); let arm_cxs = [], arm_dests = [], i = 0u; for a: ast::arm in arms { let body_cx = bodies[i]; if make_phi_bindings(body_cx, exit_map, ast_util::pat_id_map(a.pats[0])) { let arm_dest = trans::dup_for_join(dest); arm_dests += [arm_dest]; arm_cxs += [trans::trans_block_dps(body_cx, a.body, arm_dest)]; } i += 1u; } ret trans::join_returns(cx, arm_cxs, arm_dests, dest); } // Not alt-related, but similar to the pattern-munging code above fn bind_irrefutable_pat(bcx: @block_ctxt, pat: @ast::pat, val: ValueRef, table: hashmap, make_copy: bool) -> @block_ctxt { let ccx = bcx.fcx.lcx.ccx; alt pat.node { ast::pat_bind(_) { if make_copy || ccx.copy_map.contains_key(pat.id) { let ty = ty::node_id_to_monotype(ccx.tcx, pat.id); // FIXME: Could constrain pat_bind to make this // check unnecessary. check (type_has_static_size(ccx, ty)); check non_ty_var(ccx, ty); let llty = trans::type_of(ccx, pat.span, ty); let alloc = trans::alloca(bcx, llty); bcx = trans::copy_val(bcx, trans::INIT, alloc, trans::load_if_immediate(bcx, val, ty), ty); table.insert(pat.id, alloc); trans_common::add_clean(bcx, alloc, ty); } else { table.insert(pat.id, val); } } ast::pat_tag(_, sub) { if vec::len(sub) == 0u { ret bcx; } let vdefs = ast_util::variant_def_ids(ccx.tcx.def_map.get(pat.id)); let args = extract_variant_args(bcx, pat.id, vdefs, val); let i = 0; for argval: ValueRef in args.vals { bcx = bind_irrefutable_pat(bcx, sub[i], argval, table, make_copy); i += 1; } } ast::pat_rec(fields, _) { let rec_ty = ty::node_id_to_monotype(ccx.tcx, pat.id); let rec_fields = alt ty::struct(ccx.tcx, rec_ty) { ty::ty_rec(fields) { fields } }; for f: ast::field_pat in fields { let ix: uint = ty::field_idx(ccx.sess, pat.span, f.ident, rec_fields); // how to get rid of this check? check type_is_tup_like(bcx, rec_ty); let r = trans::GEP_tup_like(bcx, rec_ty, val, [0, ix as int]); bcx = bind_irrefutable_pat(r.bcx, f.pat, r.val, table, make_copy); } } ast::pat_tup(elems) { let tup_ty = ty::node_id_to_monotype(ccx.tcx, pat.id); let i = 0u; for elem in elems { // how to get rid of this check? check type_is_tup_like(bcx, tup_ty); let r = trans::GEP_tup_like(bcx, tup_ty, val, [0, i as int]); bcx = bind_irrefutable_pat(r.bcx, elem, r.val, table, make_copy); i += 1u; } } ast::pat_box(inner) { let box = Load(bcx, val); let unboxed = InBoundsGEP(bcx, box, [C_int(0), C_int(back::abi::box_rc_field_body)]); bcx = bind_irrefutable_pat(bcx, inner, unboxed, table, true); } ast::pat_uniq(inner) { let val = Load(bcx, val); bcx = bind_irrefutable_pat(bcx, inner, val, table, true); } ast::pat_wild. | ast::pat_lit(_) { } } ret bcx; } // Local Variables: // fill-column: 78; // indent-tabs-mode: nil // c-basic-offset: 4 // buffer-file-coding-system: utf-8-unix // compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'"; // End: