transIntLiteral

fn transIntLiteral(
    t: *Translator,
    scope: *Scope,
    literal_index: Node.Index,
    used: ResultUsed,
    suppress_as: SuppressCast,
) TransError!ZigNode

File

Code

fn transIntLiteral(
    t: *Translator,
    scope: *Scope,
    literal_index: Node.Index,
    used: ResultUsed,
    suppress_as: SuppressCast,
) TransError!ZigNode {
    if (try t.checkLiteralMacro(literal_index.tok(t.tree), used)) |node| return node;
    const val = t.tree.value_map.get(literal_index).?;
    const int_lit_node = try t.createIntNode(val);
    if (suppress_as == .no_as) {
        return t.maybeSuppressResult(used, int_lit_node);
    }

    // Integer literals in C have types, and this can matter for several reasons.
    // For example, this is valid C:
    //     unsigned char y = 256;
    // How this gets evaluated is the 256 is an integer, which gets truncated to signed char, then bit-casted
    // to unsigned char, resulting in 0. In order for this to work, we have to emit this zig code:
    //     var y = @as(u8, @bitCast(@as(i8, @truncate(@as(c_int, 256)))));

    // @as(T, x)
    const ty_node = try t.transType(scope, literal_index.qt(t.tree), literal_index.tok(t.tree));
    const as = try ZigTag.as.create(t.arena, .{ .lhs = ty_node, .rhs = int_lit_node });
    return t.maybeSuppressResult(used, as);
}