transIncDecExpr

fn transIncDecExpr(
    t: *Translator,
    scope: *Scope,
    un: Node.Unary,
    position: enum

File

Code

fn transIncDecExpr(
    t: *Translator,
    scope: *Scope,
    un: Node.Unary,
    position: enum { pre, post },
    kind: enum { inc, dec },
    used: ResultUsed,
) !ZigNode {
    const is_wrapping = t.typeHasWrappingOverflow(un.qt);
    const op: ZigTag = switch (kind) {
        .inc => if (is_wrapping) .add_wrap_assign else .add_assign,
        .dec => if (is_wrapping) .sub_wrap_assign else .sub_assign,
    };

    const one_literal = ZigTag.one_literal.init();
    if (used == .unused) {
        const operand = try t.transExpr(scope, un.operand, .used);
        return try t.createBinOpNode(op, operand, one_literal);
    }

    var block_scope = try Scope.Block.init(t, scope, true);
    defer block_scope.deinit();

    const ref = try block_scope.reserveMangledName("ref");
    const operand = try t.transExprCoercing(&block_scope.base, un.operand, .used);
    const operand_ref = try ZigTag.address_of.create(t.arena, operand);
    const ref_decl = try ZigTag.var_simple.create(t.arena, .{ .name = ref, .init = operand_ref });
    try block_scope.statements.append(t.gpa, ref_decl);

    const ref_ident = try ZigTag.identifier.create(t.arena, ref);
    const ref_deref = try ZigTag.deref.create(t.arena, ref_ident);
    const effect = try t.createBinOpNode(op, ref_deref, one_literal);

    switch (position) {
        .pre => {
            try block_scope.statements.append(t.gpa, effect);

            const break_node = try ZigTag.break_val.create(t.arena, .{
                .label = block_scope.label,
                .val = ref_deref,
            });
            try block_scope.statements.append(t.gpa, break_node);
        },
        .post => {
            const tmp = try block_scope.reserveMangledName("tmp");
            const tmp_decl = try ZigTag.var_simple.create(t.arena, .{ .name = tmp, .init = ref_deref });
            try block_scope.statements.append(t.gpa, tmp_decl);

            try block_scope.statements.append(t.gpa, effect);

            const tmp_ident = try ZigTag.identifier.create(t.arena, tmp);
            const break_node = try ZigTag.break_val.create(t.arena, .{
                .label = block_scope.label,
                .val = tmp_ident,
            });
            try block_scope.statements.append(t.gpa, break_node);
        },
    }

    return try block_scope.complete();
}