compiler-rt/lib/sanitizer_common/tests/sanitizer_leb128_test.cpp

   1 //===-- sanitizer_leb128.cpp ------------------------------------*- C++ -*-===//
   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 #include "sanitizer_common/sanitizer_leb128.h"
   9
  10 #include <type_traits>
  11
  12 #include "gtest/gtest.h"
  13 #include "sanitizer_common/sanitizer_common.h"
  14 #include "sanitizer_internal_defs.h"
  15
  16 namespace __sanitizer {
  17
  18 template <typename T>
  19 class Leb128Test : public ::testing::Test {};
  20
  21 using Leb128TestTypes = ::testing::Types<u8, u16, u32, u64>;
  22 TYPED_TEST_SUITE(Leb128Test, Leb128TestTypes, );
  23
  24 static uptr BitsNeeded(u64 v) {
  25   if (!v)
  26     return 1;
  27   uptr r = 0;
  28   uptr uptr_bits = 8 * sizeof(uptr);
  29   while (v >> uptr_bits) {
  30     r += uptr_bits;
  31     v >>= uptr_bits;
  32   }
  33   return r + MostSignificantSetBitIndex(v) + 1;
  34 }
  35
  36 TYPED_TEST(Leb128Test, SignedOverflow) {
  37   using T = typename std::make_signed<TypeParam>::type;
  38   u8 buffer[16] = {255};
  39   T v = -128;
  40   EXPECT_EQ(buffer + 1, EncodeSLEB128(v, buffer, buffer + 1));
  41   EXPECT_EQ(buffer + 1, DecodeSLEB128(buffer, buffer + 1, &v));
  42 }
  43
  44 TYPED_TEST(Leb128Test, Signed) {
  45   using T = typename std::make_signed<TypeParam>::type;
  46   T v = 0;
  47   for (int i = 0; i < 100; ++i) {
  48     u8 buffer[16] = {};
  49     u8* p = EncodeSLEB128(v, std::begin(buffer), std::end(buffer));
  50     EXPECT_EQ(int(BitsNeeded(v < 0 ? (-v - 1) : v) + 6 + 1) / 7, p - buffer)
  51         << (int)v;
  52     T v2;
  53     u8* p2 = DecodeSLEB128(std::begin(buffer), std::end(buffer), &v2);
  54     EXPECT_EQ(v, v2);
  55     EXPECT_EQ(p, p2);
  56     v = -TypeParam(v) * 3u + 1u;
  57   }
  58 }
  59
  60 TYPED_TEST(Leb128Test, UnsignedOverflow) {
  61   using T = TypeParam;
  62   u8 buffer[16] = {255};
  63   T v = 255;
  64   EXPECT_EQ(buffer + 1, EncodeULEB128(v, buffer, buffer + 1));
  65   EXPECT_EQ(buffer + 1, DecodeULEB128(buffer, buffer + 1, &v));
  66 }
  67
  68 TYPED_TEST(Leb128Test, Unsigned) {
  69   using T = TypeParam;
  70   T v = 0;
  71   for (int i = 0; i < 100; ++i) {
  72     u8 buffer[16] = {};
  73     u8* p = EncodeULEB128(v, std::begin(buffer), std::end(buffer));
  74     EXPECT_EQ(int(BitsNeeded(v) + 6) / 7, p - buffer);
  75     T v2;
  76     u8* p2 = DecodeULEB128(std::begin(buffer), std::end(buffer), &v2);
  77     EXPECT_EQ(v, v2);
  78     EXPECT_EQ(p, p2);
  79     v = v * 3 + 1;
  80   }
  81 }
  82
  83 }  // namespace __sanitizer