diff options
| -rw-r--r-- | src/Makefile.am | 1 | ||||
| -rw-r--r-- | src/compat/assumptions.h | 49 | ||||
| -rw-r--r-- | src/util/system.h | 1 |
3 files changed, 51 insertions, 0 deletions
diff --git a/src/Makefile.am b/src/Makefile.am index e3f5734c0b..d491530ca1 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -118,6 +118,7 @@ BITCOIN_CORE_H = \ clientversion.h \ coins.h \ compat.h \ + compat/assumptions.h \ compat/byteswap.h \ compat/endian.h \ compat/sanity.h \ diff --git a/src/compat/assumptions.h b/src/compat/assumptions.h new file mode 100644 index 0000000000..820c9b93d9 --- /dev/null +++ b/src/compat/assumptions.h @@ -0,0 +1,49 @@ +// Copyright (c) 2009-2010 Satoshi Nakamoto +// Copyright (c) 2009-2019 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +// Compile-time verification of assumptions we make. + +#ifndef BITCOIN_COMPAT_ASSUMPTIONS_H +#define BITCOIN_COMPAT_ASSUMPTIONS_H + +#include <limits> + +// Assumption: We assume that the macro NDEBUG is not defined. +// Example(s): We use assert(...) extensively with the assumption of it never +// being a noop at runtime. +#if defined(NDEBUG) +# error "Bitcoin cannot be compiled without assertions." +#endif + +// Assumption: We assume the floating-point types to fulfill the requirements of +// IEC 559 (IEEE 754) standard. +// Example(s): Floating-point division by zero in ConnectBlock, CreateTransaction +// and EstimateMedianVal. +static_assert(std::numeric_limits<float>::is_iec559, "IEEE 754 float assumed"); +static_assert(std::numeric_limits<double>::is_iec559, "IEEE 754 double assumed"); + +// Assumption: We assume eight bits per byte (obviously, but remember: don't +// trust -- verify!). +// Example(s): Everywhere :-) +static_assert(std::numeric_limits<unsigned char>::digits == 8, "8-bit byte assumed"); + +// Assumption: We assume floating-point widths. +// Example(s): Type punning in serialization code (ser_{float,double}_to_uint{32,64}). +static_assert(sizeof(float) == 4, "32-bit float assumed"); +static_assert(sizeof(double) == 8, "64-bit double assumed"); + +// Assumption: We assume integer widths. +// Example(s): GetSizeOfCompactSize and WriteCompactSize in the serialization +// code. +static_assert(sizeof(short) == 2, "16-bit short assumed"); +static_assert(sizeof(int) == 4, "32-bit int assumed"); + +// Some important things we are NOT assuming (non-exhaustive list): +// * We are NOT assuming a specific value for sizeof(std::size_t). +// * We are NOT assuming a specific value for std::endian::native. +// * We are NOT assuming a specific value for std::locale("").name(). +// * We are NOT assuming a specific value for std::numeric_limits<char>::is_signed. + +#endif // BITCOIN_COMPAT_ASSUMPTIONS_H diff --git a/src/util/system.h b/src/util/system.h index 54d4cf2e58..8867e49478 100644 --- a/src/util/system.h +++ b/src/util/system.h @@ -16,6 +16,7 @@ #include <attributes.h> #include <compat.h> +#include <compat/assumptions.h> #include <fs.h> #include <logging.h> #include <sync.h> |