Index: compiler-rt/trunk/lib/fuzzer/utils/FuzzedDataProvider.h =================================================================== --- compiler-rt/trunk/lib/fuzzer/utils/FuzzedDataProvider.h +++ compiler-rt/trunk/lib/fuzzer/utils/FuzzedDataProvider.h @@ -1,247 +0,0 @@ -//===- FuzzedDataProvider.h - Utility header for fuzz targets ---*- C++ -* ===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// -// This a temporary copy of compiler-rt/include/fuzzer/FuzzedDataProvider.h. -// TODO(mmoroz@chromium.org): delete this copy. -// A single header library providing an utility class to break up an array of -// bytes. Whenever run on the same input, provides the same output, as long as -// its methods are called in the same order, with the same arguments. -//===----------------------------------------------------------------------===// - -#ifndef LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_ -#define LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_ - -#include -#include -#include - -#include -#include -#include -#include -#include -#include -#include - -class FuzzedDataProvider { - public: - // |data| is an array of length |size| that the FuzzedDataProvider wraps to - // provide more granular access. |data| must outlive the FuzzedDataProvider. - FuzzedDataProvider(const uint8_t *data, size_t size) - : data_ptr_(data), remaining_bytes_(size) {} - ~FuzzedDataProvider() = default; - - // Returns a std::vector containing |num_bytes| of input data. If fewer than - // |num_bytes| of data remain, returns a shorter std::vector containing all - // of the data that's left. Can be used with any byte sized type, such as - // char, unsigned char, uint8_t, etc. - template std::vector ConsumeBytes(size_t num_bytes) { - num_bytes = std::min(num_bytes, remaining_bytes_); - return ConsumeBytes(num_bytes, num_bytes); - } - - // Similar to |ConsumeBytes|, but also appends the terminator value at the end - // of the resulting vector. Useful, when a mutable null-terminated C-string is - // needed, for example. But that is a rare case. Better avoid it, if possible, - // and prefer using |ConsumeBytes| or |ConsumeBytesAsString| methods. - template - std::vector ConsumeBytesWithTerminator(size_t num_bytes, - T terminator = 0) { - num_bytes = std::min(num_bytes, remaining_bytes_); - std::vector result = ConsumeBytes(num_bytes + 1, num_bytes); - result.back() = terminator; - return result; - } - - // Returns a std::string containing |num_bytes| of input data. Using this and - // |.c_str()| on the resulting string is the best way to get an immutable - // null-terminated C string. If fewer than |num_bytes| of data remain, returns - // a shorter std::string containing all of the data that's left. - std::string ConsumeBytesAsString(size_t num_bytes) { - static_assert(sizeof(std::string::value_type) == sizeof(uint8_t), - "ConsumeBytesAsString cannot convert the data to a string."); - - num_bytes = std::min(num_bytes, remaining_bytes_); - std::string result( - reinterpret_cast(data_ptr_), - num_bytes); - Advance(num_bytes); - return result; - } - - // Returns a number in the range [min, max] by consuming bytes from the - // input data. The value might not be uniformly distributed in the given - // range. If there's no input data left, always returns |min|. |min| must - // be less than or equal to |max|. - template T ConsumeIntegralInRange(T min, T max) { - static_assert(std::is_integral::value, "An integral type is required."); - static_assert(sizeof(T) <= sizeof(uint64_t), "Unsupported integral type."); - - if (min > max) - abort(); - - // Use the biggest type possible to hold the range and the result. - uint64_t range = static_cast(max) - min; - uint64_t result = 0; - size_t offset = 0; - - while (offset < sizeof(T) * CHAR_BIT && (range >> offset) > 0 && - remaining_bytes_ != 0) { - // Pull bytes off the end of the seed data. Experimentally, this seems to - // allow the fuzzer to more easily explore the input space. This makes - // sense, since it works by modifying inputs that caused new code to run, - // and this data is often used to encode length of data read by - // |ConsumeBytes|. Separating out read lengths makes it easier modify the - // contents of the data that is actually read. - --remaining_bytes_; - result = (result << CHAR_BIT) | data_ptr_[remaining_bytes_]; - offset += CHAR_BIT; - } - - // Avoid division by 0, in case |range + 1| results in overflow. - if (range != std::numeric_limits::max()) - result = result % (range + 1); - - return static_cast(min + result); - } - - // Returns a std::string of length from 0 to |max_length|. When it runs out of - // input data, returns what remains of the input. Designed to be more stable - // with respect to a fuzzer inserting characters than just picking a random - // length and then consuming that many bytes with |ConsumeBytes|. - std::string ConsumeRandomLengthString(size_t max_length) { - // Reads bytes from the start of |data_ptr_|. Maps "\\" to "\", and maps "\" - // followed by anything else to the end of the string. As a result of this - // logic, a fuzzer can insert characters into the string, and the string - // will be lengthened to include those new characters, resulting in a more - // stable fuzzer than picking the length of a string independently from - // picking its contents. - std::string result; - - // Reserve the anticipated capaticity to prevent several reallocations. - result.reserve(std::min(max_length, remaining_bytes_)); - for (size_t i = 0; i < max_length && remaining_bytes_ != 0; ++i) { - char next = ConvertUnsignedToSigned(data_ptr_[0]); - Advance(1); - if (next == '\\' && remaining_bytes_ != 0) { - next = ConvertUnsignedToSigned(data_ptr_[0]); - Advance(1); - if (next != '\\') - break; - } - result += next; - } - - result.shrink_to_fit(); - return result; - } - - // Returns a std::vector containing all remaining bytes of the input data. - template std::vector ConsumeRemainingBytes() { - return ConsumeBytes(remaining_bytes_); - } - - // Prefer using |ConsumeRemainingBytes| unless you actually need a std::string - // object. - // Returns a std::vector containing all remaining bytes of the input data. - std::string ConsumeRemainingBytesAsString() { - return ConsumeBytesAsString(remaining_bytes_); - } - - // Returns a number in the range [Type's min, Type's max]. The value might - // not be uniformly distributed in the given range. If there's no input data - // left, always returns |min|. - template T ConsumeIntegral() { - return ConsumeIntegralInRange(std::numeric_limits::min(), - std::numeric_limits::max()); - } - - // Reads one byte and returns a bool, or false when no data remains. - bool ConsumeBool() { return 1 & ConsumeIntegral(); } - - // Returns a copy of a value selected from a fixed-size |array|. - template - T PickValueInArray(const T (&array)[size]) { - static_assert(size > 0, "The array must be non empty."); - return array[ConsumeIntegralInRange(0, size - 1)]; - } - - template - T PickValueInArray(std::initializer_list list) { - // static_assert(list.size() > 0, "The array must be non empty."); - return *(list.begin() + ConsumeIntegralInRange(0, list.size() - 1)); - } - - // Return an enum value. The enum must start at 0 and be contiguous. It must - // also contain |kMaxValue| aliased to its largest (inclusive) value. Such as: - // enum class Foo { SomeValue, OtherValue, kMaxValue = OtherValue }; - template T ConsumeEnum() { - static_assert(std::is_enum::value, "|T| must be an enum type."); - return static_cast(ConsumeIntegralInRange( - 0, static_cast(T::kMaxValue))); - } - - // Reports the remaining bytes available for fuzzed input. - size_t remaining_bytes() { return remaining_bytes_; } - - private: - FuzzedDataProvider(const FuzzedDataProvider &) = delete; - FuzzedDataProvider &operator=(const FuzzedDataProvider &) = delete; - - void Advance(size_t num_bytes) { - if (num_bytes > remaining_bytes_) - abort(); - - data_ptr_ += num_bytes; - remaining_bytes_ -= num_bytes; - } - - template - std::vector ConsumeBytes(size_t size, size_t num_bytes_to_consume) { - static_assert(sizeof(T) == sizeof(uint8_t), "Incompatible data type."); - - // The point of using the size-based constructor below is to increase the - // odds of having a vector object with capacity being equal to the length. - // That part is always implementation specific, but at least both libc++ and - // libstdc++ allocate the requested number of bytes in that constructor, - // which seems to be a natural choice for other implementations as well. - // To increase the odds even more, we also call |shrink_to_fit| below. - std::vector result(size); - std::memcpy(result.data(), data_ptr_, num_bytes_to_consume); - Advance(num_bytes_to_consume); - - // Even though |shrink_to_fit| is also implementation specific, we expect it - // to provide an additional assurance in case vector's constructor allocated - // a buffer which is larger than the actual amount of data we put inside it. - result.shrink_to_fit(); - return result; - } - - template TS ConvertUnsignedToSigned(TU value) { - static_assert(sizeof(TS) == sizeof(TU), "Incompatible data types."); - static_assert(!std::numeric_limits::is_signed, - "Source type must be unsigned."); - - // TODO(Dor1s): change to `if constexpr` once C++17 becomes mainstream. - if (std::numeric_limits::is_modulo) - return static_cast(value); - - // Avoid using implementation-defined unsigned to signer conversions. - // To learn more, see https://stackoverflow.com/questions/13150449. - if (value <= std::numeric_limits::max()) - return static_cast(value); - else { - constexpr auto TS_min = std::numeric_limits::min(); - return TS_min + static_cast(value - TS_min); - } - } - - const uint8_t *data_ptr_; - size_t remaining_bytes_; -}; - -#endif // LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_