[flang][NFC] Use LLVM's endianness enum

[tarunprabhu]

Replace the FLANG_LITTLE_ENDIAN and FLANG_BIG_ENDIAN preprocessor defines with equivalents from LLVM. This ensures that tools that use flang's headers are not required to provide these preorocessor defines themselves.

[github-actions]

✅ With the latest revision this PR passed the Python code formatter.

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[klausler]

You're just defaulting to little-endianness here if BYTE_ORDER is undefined. This can be worse than the current situation.

[klausler]

This initialization should use braces and does not need parentheses.

[llvmbot]

@llvm/pr-subscribers-flang-semantics

@llvm/pr-subscribers-flang-runtime

Author: Tarun Prabhu (tarunprabhu)

Changes

Replace the FLANG_LITTLE_ENDIAN and FLANG_BIG_ENDIAN preprocessor defines with equivalents from LLVM. This ensures that tools that use flang's headers are not required to provide these preorocessor defines themselves.

---

Full diff: https://github.com/llvm/llvm-project/pull/86516.diff

3 Files Affected:

• (modified) flang/include/flang/Common/uint128.h (+3-4)
• (modified) flang/include/flang/Evaluate/common.h (+3-7)
• (modified) flang/runtime/environment.h (+4-7)

diff --git a/flang/include/flang/Common/uint128.h b/flang/include/flang/Common/uint128.h index 03e44eb6997d5b..4a9e5fb2e44c00 100644 --- a/flang/include/flang/Common/uint128.h +++ b/flang/include/flang/Common/uint128.h @@ -20,6 +20,7 @@ #endif #include "leading-zero-bit-count.h" +#include "llvm/ADT/bit.h" #include <cstdint> #include <type_traits> @@ -261,12 +262,10 @@ template <bool IS_SIGNED = false> class Int128 { } } static constexpr std::uint64_t topBit{std::uint64_t{1} << 63}; -#if FLANG_LITTLE_ENDIAN - std::uint64_t low_{0}, high_{0}; -#elif FLANG_BIG_ENDIAN +#if defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN std::uint64_t high_{0}, low_{0}; #else -#error host endianness is not known + std::uint64_t low_{0}, high_{0}; #endif }; diff --git a/flang/include/flang/Evaluate/common.h b/flang/include/flang/Evaluate/common.h index d04c901929e74b..39f63311e7944e 100644 --- a/flang/include/flang/Evaluate/common.h +++ b/flang/include/flang/Evaluate/common.h @@ -18,6 +18,7 @@ #include "flang/Common/restorer.h" #include "flang/Parser/char-block.h" #include "flang/Parser/message.h" +#include "llvm/ADT/bit.h" #include <cinttypes> #include <map> #include <set> @@ -142,13 +143,8 @@ template <typename A> struct ValueWithRealFlags { RealFlags flags{}; }; -#if FLANG_BIG_ENDIAN -constexpr bool isHostLittleEndian{false}; -#elif FLANG_LITTLE_ENDIAN -constexpr bool isHostLittleEndian{true}; -#else -#error host endianness is not known -#endif +constexpr bool isHostLittleEndian = + (llvm::endianness::native == llvm::endianness::little); // HostUnsignedInt<BITS> finds the smallest native unsigned integer type // whose size is >= BITS. diff --git a/flang/runtime/environment.h b/flang/runtime/environment.h index 9bc1158509615f..f42312d73f439c 100644 --- a/flang/runtime/environment.h +++ b/flang/runtime/environment.h @@ -12,19 +12,16 @@ #include "flang/Common/optional.h" #include "flang/Decimal/decimal.h" +#include "llvm/ADT/bit.h" + struct EnvironmentDefaultList; namespace Fortran::runtime { class Terminator; -#if FLANG_BIG_ENDIAN -constexpr bool isHostLittleEndian{false}; -#elif FLANG_LITTLE_ENDIAN -constexpr bool isHostLittleEndian{true}; -#else -#error host endianness is not known -#endif +constexpr bool isHostLittleEndian = + (llvm::endianness::native == llvm::endianness::little); // External unformatted I/O data conversions enum class Convert { Unknown, Native, LittleEndian, BigEndian, Swap };