421 lines
11 KiB
V
421 lines
11 KiB
V
// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module c
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import v.ast
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fn (mut g Gen) need_tmp_var_in_match(node ast.MatchExpr) bool {
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if node.is_expr && node.return_type != ast.void_type && node.return_type != 0 {
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cond_sym := g.table.final_sym(node.cond_type)
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sym := g.table.sym(node.return_type)
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if g.table.type_kind(node.return_type) == .sum_type {
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return true
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}
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if node.return_type.has_flag(.optional) {
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return true
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}
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if sym.kind == .multi_return {
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return false
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}
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if cond_sym.kind == .enum_ && node.branches.len > 5 {
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return true
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}
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for branch in node.branches {
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if branch.stmts.len > 1 {
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return true
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}
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if branch.stmts.len == 1 {
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if branch.stmts[0] is ast.ExprStmt {
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stmt := branch.stmts[0] as ast.ExprStmt
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if stmt.expr in [ast.CallExpr, ast.IfExpr, ast.MatchExpr]
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|| (stmt.expr is ast.IndexExpr
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&& (stmt.expr as ast.IndexExpr).or_expr.kind != .absent) {
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return true
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}
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}
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}
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}
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}
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return false
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}
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fn (mut g Gen) match_expr(node ast.MatchExpr) {
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if node.cond_type == 0 {
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g.writeln('// match 0')
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return
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}
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need_tmp_var := g.need_tmp_var_in_match(node)
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is_expr := (node.is_expr && node.return_type != ast.void_type) || g.inside_ternary > 0
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mut cond_var := ''
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mut tmp_var := ''
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mut cur_line := ''
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if is_expr && !need_tmp_var {
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g.inside_ternary++
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}
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if is_expr && node.return_type.has_flag(.optional) {
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old := g.inside_match_optional
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defer {
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g.inside_match_optional = old
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}
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g.inside_match_optional = true
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}
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if node.cond in [ast.Ident, ast.SelectorExpr, ast.IntegerLiteral, ast.StringLiteral, ast.FloatLiteral] {
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cond_var = g.expr_string(node.cond)
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} else {
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line := if is_expr {
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g.empty_line = true
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g.go_before_stmt(0)
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} else {
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''
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}
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cond_var = g.new_tmp_var()
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g.write('${g.typ(node.cond_type)} $cond_var = ')
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g.expr(node.cond)
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g.writeln(';')
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g.set_current_pos_as_last_stmt_pos()
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g.write(line)
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}
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if need_tmp_var {
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g.empty_line = true
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cur_line = g.go_before_stmt(0).trim_left(' \t')
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tmp_var = g.new_tmp_var()
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g.writeln('${g.typ(node.return_type)} $tmp_var = ${g.type_default(node.return_type)};')
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}
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if is_expr && !need_tmp_var {
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// brackets needed otherwise '?' will apply to everything on the left
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g.write('(')
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}
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typ := g.table.final_sym(node.cond_type)
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if node.is_sum_type {
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g.match_expr_sumtype(node, is_expr, cond_var, tmp_var)
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} else if typ.kind == .enum_ && g.loop_depth == 0 && node.branches.len > 5 && g.fn_decl != 0 { // do not optimize while in top-level
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g.match_expr_switch(node, is_expr, cond_var, tmp_var, typ)
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} else {
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g.match_expr_classic(node, is_expr, cond_var, tmp_var)
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}
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g.set_current_pos_as_last_stmt_pos()
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g.write(cur_line)
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if need_tmp_var {
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g.write('$tmp_var')
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}
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if is_expr && !need_tmp_var {
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g.write(')')
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g.decrement_inside_ternary()
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}
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}
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fn (mut g Gen) match_expr_sumtype(node ast.MatchExpr, is_expr bool, cond_var string, tmp_var string) {
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for j, branch in node.branches {
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mut sumtype_index := 0
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// iterates through all types in sumtype branches
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for {
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g.aggregate_type_idx = sumtype_index
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is_last := j == node.branches.len - 1
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sym := g.table.sym(node.cond_type)
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if branch.is_else || (node.is_expr && is_last && tmp_var.len == 0) {
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if is_expr && tmp_var.len == 0 {
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// TODO too many branches. maybe separate ?: matches
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g.write(' : ')
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} else {
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g.writeln('')
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g.write_v_source_line_info(branch.pos)
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g.writeln('else {')
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}
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} else {
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if j > 0 || sumtype_index > 0 {
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if is_expr && tmp_var.len == 0 {
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g.write(' : ')
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} else {
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g.write_v_source_line_info(branch.pos)
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g.write('else ')
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}
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}
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if is_expr && tmp_var.len == 0 {
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g.write('(')
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} else {
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if j == 0 && sumtype_index == 0 {
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g.empty_line = true
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}
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g.write_v_source_line_info(branch.pos)
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g.write('if (')
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}
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g.write(cond_var)
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dot_or_ptr := if node.cond_type.is_ptr() { '->' } else { '.' }
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if sym.kind == .sum_type {
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g.write('${dot_or_ptr}_typ == ')
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g.expr(branch.exprs[sumtype_index])
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} else if sym.kind == .interface_ {
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if branch.exprs[sumtype_index] is ast.TypeNode {
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typ := branch.exprs[sumtype_index] as ast.TypeNode
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branch_sym := g.table.sym(g.unwrap_generic(typ.typ))
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g.write('${dot_or_ptr}_typ == _${sym.cname}_${branch_sym.cname}_index')
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} else if branch.exprs[sumtype_index] is ast.None
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&& sym.idx == ast.error_type_idx {
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g.write('${dot_or_ptr}_typ == _IError_None___index')
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}
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}
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if is_expr && tmp_var.len == 0 {
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g.write(') ? ')
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} else {
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g.writeln(') {')
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}
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}
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if is_expr && tmp_var.len > 0 && g.table.sym(node.return_type).kind == .sum_type {
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g.expected_cast_type = node.return_type
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}
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g.stmts_with_tmp_var(branch.stmts, tmp_var)
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g.expected_cast_type = 0
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if g.inside_ternary == 0 {
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g.writeln('}')
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g.set_current_pos_as_last_stmt_pos()
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}
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sumtype_index++
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if branch.exprs.len == 0 || sumtype_index == branch.exprs.len {
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break
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}
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}
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// reset global field for next use
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g.aggregate_type_idx = 0
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}
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}
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fn (mut g Gen) match_expr_switch(node ast.MatchExpr, is_expr bool, cond_var string, tmp_var string, enum_typ ast.TypeSymbol) {
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cname := '${enum_typ.cname}__'
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mut covered_enum := []string{cap: (enum_typ.info as ast.Enum).vals.len} // collects missing enum variant branches to avoid cstrict errors
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mut range_branches := []ast.MatchBranch{cap: node.branches.len} // branches have RangeExpr cannot emit as switch case branch, we handle it in default branch
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mut default_generated := false
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g.empty_line = true
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g.writeln('switch ($cond_var) {')
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g.indent++
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for branch in node.branches {
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if branch.is_else {
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for val in (enum_typ.info as ast.Enum).vals {
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if val !in covered_enum {
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g.writeln('case $cname$val:')
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}
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}
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g.writeln('default:')
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default_generated = true
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if range_branches.len > 0 {
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g.indent++
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for range_branch in range_branches {
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g.write('if (')
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for i, expr in range_branch.exprs {
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if i > 0 {
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g.write(' || ')
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}
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if expr is ast.RangeExpr {
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// if type is unsigned and low is 0, check is unneeded
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mut skip_low := false
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if expr.low is ast.IntegerLiteral {
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if node.cond_type in [ast.u16_type, ast.u32_type, ast.u64_type]
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&& expr.low.val == '0' {
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skip_low = true
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}
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}
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g.write('(')
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if !skip_low {
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g.write('$cond_var >= ')
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g.expr(expr.low)
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g.write(' && ')
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}
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g.write('$cond_var <= ')
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g.expr(expr.high)
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g.write(')')
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} else {
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g.write('$cond_var == (')
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g.expr(expr)
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g.write(')')
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}
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}
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g.writeln(') {')
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g.stmts_with_tmp_var(range_branch.stmts, tmp_var)
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g.writeln('\tbreak;')
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g.writeln('}')
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}
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g.indent--
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}
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} else {
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if branch.exprs.any(it is ast.RangeExpr) {
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range_branches << branch
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continue
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}
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for expr in branch.exprs {
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if expr is ast.EnumVal {
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covered_enum << expr.val
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g.write('case ')
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g.expr(expr)
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g.writeln(': ')
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}
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}
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}
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g.indent++
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g.writeln('{')
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if is_expr && tmp_var.len > 0 && g.table.sym(node.return_type).kind == .sum_type {
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g.expected_cast_type = node.return_type
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}
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g.stmts_with_tmp_var(branch.stmts, tmp_var)
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g.expected_cast_type = 0
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g.writeln('\tbreak;')
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g.writeln('}')
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g.indent--
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}
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if range_branches.len > 0 && !default_generated {
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g.writeln('default:')
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g.indent++
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for range_branch in range_branches {
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g.write('if (')
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for i, expr in range_branch.exprs {
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if i > 0 {
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g.write(' || ')
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}
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if expr is ast.RangeExpr {
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// if type is unsigned and low is 0, check is unneeded
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mut skip_low := false
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if expr.low is ast.IntegerLiteral {
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if node.cond_type in [ast.u16_type, ast.u32_type, ast.u64_type]
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&& expr.low.val == '0' {
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skip_low = true
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}
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}
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g.write('(')
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if !skip_low {
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g.write('$cond_var >= ')
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g.expr(expr.low)
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g.write(' && ')
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}
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g.write('$cond_var <= ')
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g.expr(expr.high)
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g.write(')')
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} else {
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g.write('$cond_var == (')
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g.expr(expr)
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g.write(')')
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}
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}
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g.writeln(') {')
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g.stmts_with_tmp_var(range_branch.stmts, tmp_var)
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g.writeln('\tbreak;')
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g.writeln('}')
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}
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g.indent--
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}
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g.indent--
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g.writeln('}')
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}
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fn (mut g Gen) match_expr_classic(node ast.MatchExpr, is_expr bool, cond_var string, tmp_var string) {
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type_sym := g.table.sym(node.cond_type)
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for j, branch in node.branches {
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is_last := j == node.branches.len - 1
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if branch.is_else || (node.is_expr && is_last && tmp_var.len == 0) {
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if node.branches.len > 1 {
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if is_expr && tmp_var.len == 0 {
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// TODO too many branches. maybe separate ?: matches
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g.write(' : ')
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} else {
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g.writeln('')
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g.write_v_source_line_info(branch.pos)
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g.writeln('else {')
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}
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}
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} else {
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if j > 0 {
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if is_expr && tmp_var.len == 0 {
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g.write(' : ')
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} else {
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g.writeln('')
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g.write_v_source_line_info(branch.pos)
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g.write('else ')
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}
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}
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if is_expr && tmp_var.len == 0 {
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g.write('(')
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} else {
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if j == 0 {
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g.writeln('')
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}
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g.write_v_source_line_info(branch.pos)
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g.write('if (')
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}
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for i, expr in branch.exprs {
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if i > 0 {
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g.write(' || ')
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}
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match type_sym.kind {
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.array {
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ptr_typ := g.equality_fn(node.cond_type)
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g.write('${ptr_typ}_arr_eq($cond_var, ')
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g.expr(expr)
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g.write(')')
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}
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.array_fixed {
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ptr_typ := g.equality_fn(node.cond_type)
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g.write('${ptr_typ}_arr_eq($cond_var, ')
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g.expr(expr)
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g.write(')')
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}
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.map {
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ptr_typ := g.equality_fn(node.cond_type)
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g.write('${ptr_typ}_map_eq($cond_var, ')
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g.expr(expr)
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g.write(')')
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}
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.string {
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g.write('string__eq($cond_var, ')
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g.expr(expr)
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g.write(')')
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}
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.struct_ {
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ptr_typ := g.equality_fn(node.cond_type)
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g.write('${ptr_typ}_struct_eq($cond_var, ')
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g.expr(expr)
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g.write(')')
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}
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else {
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if expr is ast.RangeExpr {
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// if type is unsigned and low is 0, check is unneeded
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mut skip_low := false
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if expr.low is ast.IntegerLiteral {
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if node.cond_type in [ast.u16_type, ast.u32_type, ast.u64_type]
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&& expr.low.val == '0' {
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skip_low = true
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}
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}
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g.write('(')
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if !skip_low {
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g.write('$cond_var >= ')
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g.expr(expr.low)
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g.write(' && ')
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}
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g.write('$cond_var <= ')
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g.expr(expr.high)
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g.write(')')
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} else {
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g.write('$cond_var == (')
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g.expr(expr)
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g.write(')')
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}
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}
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}
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}
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if is_expr && tmp_var.len == 0 {
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g.write(') ? ')
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} else {
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g.writeln(') {')
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}
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}
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if is_expr && tmp_var.len > 0 && g.table.sym(node.return_type).kind == .sum_type {
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g.expected_cast_type = node.return_type
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}
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g.stmts_with_tmp_var(branch.stmts, tmp_var)
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g.expected_cast_type = 0
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if g.inside_ternary == 0 && node.branches.len >= 1 {
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g.write('}')
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}
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}
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}
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