/Users/buildslave/jenkins/workspace/coverage/llvm-project/libcxx/src/filesystem/int128_builtins.cpp
Line | Count | Source (jump to first uncovered line) |
1 | | /*===-- int128_builtins.cpp - Implement __muloti4 --------------------------=== |
2 | | * |
3 | | * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | | * See https://llvm.org/LICENSE.txt for license information. |
5 | | * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | | * |
7 | | * ===----------------------------------------------------------------------=== |
8 | | * |
9 | | * This file implements __muloti4, and is stolen from the compiler_rt library. |
10 | | * |
11 | | * FIXME: we steal and re-compile it into filesystem, which uses __int128_t, |
12 | | * and requires this builtin when sanitized. See llvm.org/PR30643 |
13 | | * |
14 | | * ===----------------------------------------------------------------------=== |
15 | | */ |
16 | | #include <__config> |
17 | | #include <climits> |
18 | | |
19 | | #if !defined(_LIBCPP_HAS_NO_INT128) |
20 | | |
21 | | extern "C" __attribute__((no_sanitize("undefined"))) _LIBCPP_FUNC_VIS |
22 | 0 | __int128_t __muloti4(__int128_t a, __int128_t b, int* overflow) { |
23 | 0 | const int N = (int)(sizeof(__int128_t) * CHAR_BIT); |
24 | 0 | const __int128_t MIN = (__int128_t)1 << (N - 1); |
25 | 0 | const __int128_t MAX = ~MIN; |
26 | 0 | *overflow = 0; |
27 | 0 | __int128_t result = a * b; |
28 | 0 | if (a == MIN) { |
29 | 0 | if (b != 0 && b != 1) |
30 | 0 | *overflow = 1; |
31 | 0 | return result; |
32 | 0 | } |
33 | 0 | if (b == MIN) { |
34 | 0 | if (a != 0 && a != 1) |
35 | 0 | *overflow = 1; |
36 | 0 | return result; |
37 | 0 | } |
38 | 0 | __int128_t sa = a >> (N - 1); |
39 | 0 | __int128_t abs_a = (a ^ sa) - sa; |
40 | 0 | __int128_t sb = b >> (N - 1); |
41 | 0 | __int128_t abs_b = (b ^ sb) - sb; |
42 | 0 | if (abs_a < 2 || abs_b < 2) |
43 | 0 | return result; |
44 | 0 | if (sa == sb) { |
45 | 0 | if (abs_a > MAX / abs_b) |
46 | 0 | *overflow = 1; |
47 | 0 | } else { |
48 | 0 | if (abs_a > MIN / -abs_b) |
49 | 0 | *overflow = 1; |
50 | 0 | } |
51 | 0 | return result; |
52 | 0 | } |
53 | | |
54 | | #endif |