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- /* Copyright (c) 2017, Google Inc.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
- * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
- * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
- * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
-
- #include <limits.h>
- #include <stdint.h>
-
- #include <type_traits>
-
- #include <gtest/gtest.h>
-
- #include "test/test_util.h"
-
-
- template <typename T>
- static void CheckRepresentation(T value) {
- SCOPED_TRACE(value);
-
- // Convert to the corresponding two's-complement unsigned value. We use an
- // unsigned value so the right-shift below has defined value. Right-shifts of
- // negative numbers in C are implementation defined.
- //
- // If |T| is already unsigned, this is a no-op, as desired.
- //
- // If |T| is signed, conversion to unsigned is defined to repeatedly add or
- // subtract (numerically, not within |T|) one more than the unsigned type's
- // maximum value until it fits (this must be a power of two). This is the
- // conversion we want.
- using UnsignedT = typename std::make_unsigned<T>::type;
- UnsignedT value_u = static_cast<UnsignedT>(value);
- EXPECT_EQ(sizeof(UnsignedT), sizeof(T));
-
- // Integers must be little-endian.
- uint8_t expected[sizeof(UnsignedT)];
- for (size_t i = 0; i < sizeof(UnsignedT); i++) {
- expected[i] = static_cast<uint8_t>(value_u);
- // Divide instead of right-shift to appease compilers that warn if |T| is a
- // char. The explicit cast is also needed to appease MSVC if integer
- // promotion happened.
- value_u = static_cast<UnsignedT>(value_u / 256);
- }
- EXPECT_EQ(0u, value_u);
-
- // Check that |value| has the expected representation.
- EXPECT_EQ(Bytes(expected),
- Bytes(reinterpret_cast<const uint8_t *>(&value), sizeof(value)));
- }
-
- TEST(CompilerTest, IntegerRepresentation) {
- EXPECT_EQ(8, CHAR_BIT);
- EXPECT_EQ(0xff, static_cast<int>(UCHAR_MAX));
-
- // uint8_t is assumed to be unsigned char. I.e., casting to uint8_t should be
- // as good as unsigned char for strict aliasing purposes.
- uint8_t u8 = 0;
- unsigned char *ptr = &u8;
- (void)ptr;
-
- // Sized integers have the expected size.
- EXPECT_EQ(1u, sizeof(uint8_t));
- EXPECT_EQ(2u, sizeof(uint16_t));
- EXPECT_EQ(4u, sizeof(uint32_t));
- EXPECT_EQ(8u, sizeof(uint64_t));
-
- // size_t does not exceed uint64_t.
- EXPECT_LE(sizeof(size_t), 8u);
-
- // int must be 32-bit or larger.
- EXPECT_LE(0x7fffffff, INT_MAX);
- EXPECT_LE(0xffffffffu, UINT_MAX);
-
- CheckRepresentation(static_cast<signed char>(127));
- CheckRepresentation(static_cast<signed char>(1));
- CheckRepresentation(static_cast<signed char>(0));
- CheckRepresentation(static_cast<signed char>(-1));
- CheckRepresentation(static_cast<signed char>(-42));
- CheckRepresentation(static_cast<signed char>(-128));
-
- CheckRepresentation(static_cast<int>(INT_MAX));
- CheckRepresentation(static_cast<int>(0x12345678));
- CheckRepresentation(static_cast<int>(1));
- CheckRepresentation(static_cast<int>(0));
- CheckRepresentation(static_cast<int>(-1));
- CheckRepresentation(static_cast<int>(-0x12345678));
- CheckRepresentation(static_cast<int>(INT_MIN));
-
- CheckRepresentation(static_cast<unsigned>(UINT_MAX));
- CheckRepresentation(static_cast<unsigned>(0x12345678));
- CheckRepresentation(static_cast<unsigned>(1));
- CheckRepresentation(static_cast<unsigned>(0));
-
- CheckRepresentation(static_cast<long>(LONG_MAX));
- CheckRepresentation(static_cast<long>(0x12345678));
- CheckRepresentation(static_cast<long>(1));
- CheckRepresentation(static_cast<long>(0));
- CheckRepresentation(static_cast<long>(-1));
- CheckRepresentation(static_cast<long>(-0x12345678));
- CheckRepresentation(static_cast<long>(LONG_MIN));
-
- CheckRepresentation(static_cast<unsigned long>(ULONG_MAX));
- CheckRepresentation(static_cast<unsigned long>(0x12345678));
- CheckRepresentation(static_cast<unsigned long>(1));
- CheckRepresentation(static_cast<unsigned long>(0));
-
- CheckRepresentation(static_cast<int16_t>(0x7fff));
- CheckRepresentation(static_cast<int16_t>(0x1234));
- CheckRepresentation(static_cast<int16_t>(1));
- CheckRepresentation(static_cast<int16_t>(0));
- CheckRepresentation(static_cast<int16_t>(-1));
- CheckRepresentation(static_cast<int16_t>(-0x7fff - 1));
-
- CheckRepresentation(static_cast<uint16_t>(0xffff));
- CheckRepresentation(static_cast<uint16_t>(0x1234));
- CheckRepresentation(static_cast<uint16_t>(1));
- CheckRepresentation(static_cast<uint16_t>(0));
-
- CheckRepresentation(static_cast<int32_t>(0x7fffffff));
- CheckRepresentation(static_cast<int32_t>(0x12345678));
- CheckRepresentation(static_cast<int32_t>(1));
- CheckRepresentation(static_cast<int32_t>(0));
- CheckRepresentation(static_cast<int32_t>(-1));
- CheckRepresentation(static_cast<int32_t>(-0x7fffffff - 1));
-
- CheckRepresentation(static_cast<uint32_t>(0xffffffff));
- CheckRepresentation(static_cast<uint32_t>(0x12345678));
- CheckRepresentation(static_cast<uint32_t>(1));
- CheckRepresentation(static_cast<uint32_t>(0));
-
- CheckRepresentation(static_cast<int64_t>(0x7fffffffffffffff));
- CheckRepresentation(static_cast<int64_t>(0x123456789abcdef0));
- CheckRepresentation(static_cast<int64_t>(1));
- CheckRepresentation(static_cast<int64_t>(0));
- CheckRepresentation(static_cast<int64_t>(-1));
- CheckRepresentation(static_cast<int64_t>(-0x7fffffffffffffff - 1));
-
- CheckRepresentation(static_cast<uint64_t>(0xffffffffffffffff));
- CheckRepresentation(static_cast<uint64_t>(0x12345678abcdef0));
- CheckRepresentation(static_cast<uint64_t>(1));
- CheckRepresentation(static_cast<uint64_t>(0));
- }
-
- TEST(CompilerTest, PointerRepresentation) {
- // Converting pointers to integers and doing arithmetic on those values are
- // both defined. Converting those values back into pointers is undefined,
- // but, for aliasing checks, we require that the implementation-defined
- // result of that computation commutes with pointer arithmetic.
- char chars[256];
- for (size_t i = 0; i < sizeof(chars); i++) {
- EXPECT_EQ(reinterpret_cast<uintptr_t>(chars) + i,
- reinterpret_cast<uintptr_t>(chars + i));
- }
-
- int ints[256];
- for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(ints); i++) {
- EXPECT_EQ(reinterpret_cast<uintptr_t>(ints) + i * sizeof(int),
- reinterpret_cast<uintptr_t>(ints + i));
- }
-
- // nullptr must be represented by all zeros in memory. This is necessary so
- // structs may be initialized by memset(0).
- int *null = nullptr;
- uint8_t bytes[sizeof(null)] = {0};
- EXPECT_EQ(Bytes(bytes),
- Bytes(reinterpret_cast<uint8_t *>(&null), sizeof(null)));
- }
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