SIMD is wrongly enabled while building on riscv64gc

[Cryolitia]

-- ------------------------------------------------------------------------------
--     libunicode (version 0.6.0)
-- ------------------------------------------------------------------------------
-- Build type:                  None
-- Build mode:                  dynamic
-- Build unit tests:            OFF
-- Build benchmark:             OFF
-- Build tools:                 ON
-- Enable tablegen fast build:  OFF
-- Using ccache:                CCACHE-NOTFOUND
-- SIMD support:                intrinsics
-- Using UCD directory:         /build/libunicode/src/libunicode/_ucd/ucd-16.0.0
-- Enable clang-tidy:           OFF ()
-- ------------------------------------------------------------------------------
-- ==============================================================================
--     ThirdParties
-- ------------------------------------------------------------------------------
-- ------------------------------------------------------------------------------
-- Configuring done (44.2s)
-- Generating done (0.2s)
-- Build files have been written to: /build/libunicode/src/build
[0/24] Generating UCD API and tables from /build/libunicode/src/libunicode/_ucd/ucd-16.0.0
[2/24] Building CXX object src/libunicode/CMakeFiles/unicode_ucd.dir/ucd.cpp.o
[3/24] Building CXX object src/libunicode/CMakeFiles/unicode_tablegen.dir/tablegen.cpp.o
[4/24] Linking CXX shared library src/libunicode/libunicode_ucd.so.0.6.0
[5/24] Creating library symlink src/libunicode/libunicode_ucd.so.0.6 src/libunicode/libunicode_ucd.so
[6/24] Building CXX object src/libunicode/CMakeFiles/unicode_loader.dir/codepoint_properties_loader.cpp.o
[7/24] Linking CXX shared library src/libunicode/libunicode_loader.so.0.6.0
[8/24] Creating library symlink src/libunicode/libunicode_loader.so.0.6 src/libunicode/libunicode_loader.so
[9/24] Linking CXX executable src/libunicode/unicode_tablegen
[9/24] Generating UCD codepoint properties tables from /build/libunicode/src/libunicode/_ucd/ucd-16.0.0
Loading file Scripts.txt ... 152 ms
Loading file DerivedCoreProperties.txt ... 321 ms
Loading file DerivedAge.txt ... 135 ms
Loading file extracted/DerivedGeneralCategory.txt ... 399 ms
Loading file extracted/DerivedName.txt ... 376 ms
Loading file auxiliary/GraphemeBreakProperty.txt ... 28 ms
Loading file EastAsianWidth.txt ... 124 ms
Loading file emoji/emoji-data.txt ... 27 ms
Assigning EmojiSegmentationCategory ... 16 ms
Assigning char_width ... 6 ms
Creating multistage tables (properties) ... 24919 ms
Creating multistage tables (names) ... 640469 ms
Writing C++ table files ... 215 ms
[11/24] Building CXX object src/libunicode/CMakeFiles/unicode.dir/utf8.cpp.o
[12/24] Building CXX object src/libunicode/CMakeFiles/unicode.dir/script_segmenter.cpp.o
[13/24] Building CXX object src/libunicode/CMakeFiles/unicode.dir/width.cpp.o
[14/24] Building CXX object src/libunicode/CMakeFiles/unicode.dir/codepoint_properties.cpp.o
[15/24] Building CXX object src/libunicode/CMakeFiles/unicode.dir/scan.cpp.o
FAILED: src/libunicode/CMakeFiles/unicode.dir/scan.cpp.o 
/usr/bin/c++ -DUSE_INTRINSICS -D_GLIBCXX_DEBUG -Dunicode_EXPORTS -I/build/libunicode/src/libunicode/src -I/build/libunicode/src/libunicode/src/libunicode/.. -march=rv64gc -mabi=lp64d -O2 -pipe -fno-plt -fexceptions         -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security         -fstack-clash-protection         -fno-omit-frame-pointer -Wp,-D_GLIBCXX_ASSERTIONS -g -ffile-prefix-map=/build/libunicode/src=/usr/src/debug/libunicode -flto=auto -std=c++20 -fPIC -fdiagnostics-color=always -Wall -Wextra -fdiagnostics-color=always -Wconversion -Wduplicated-cond -Wextra-semi -Wimplicit-fallthrough -Wlogical-op -Wmissing-declarations -Wno-unknown-pragmas -Wnull-dereference -Wpessimizing-move -Wredundant-move -Wsign-conversion -pedantic -MD -MT src/libunicode/CMakeFiles/unicode.dir/scan.cpp.o -MF src/libunicode/CMakeFiles/unicode.dir/scan.cpp.o.d -o src/libunicode/CMakeFiles/unicode.dir/scan.cpp.o -c /build/libunicode/src/libunicode/src/libunicode/scan.cpp
/build/libunicode/src/libunicode/src/libunicode/scan.cpp: In function ‘size_t unicode::detail::scan_for_text_ascii(std::string_view, size_t)’:
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:110:5: error: ‘intrinsics’ has not been declared
  110 |     intrinsics::m128i const ControlCodeMax = intrinsics::set1_epi8(0x20); // 0..0x1F
      |     ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:111:5: error: ‘intrinsics’ has not been declared
  111 |     intrinsics::m128i const Complex = intrinsics::set1_epi8(-128);        // equals to 0x80 (0b1000'0000)
      |     ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:113:33: error: ‘intrinsics’ has not been declared
  113 |     while (input < end - sizeof(intrinsics::m128i))
      |                                 ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:115:9: error: ‘intrinsics’ has not been declared
  115 |         intrinsics::m128i batch = intrinsics::load_unaligned((intrinsics::m128i*) input);
      |         ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:116:9: error: ‘intrinsics’ has not been declared
  116 |         intrinsics::m128i isControl = intrinsics::compare_less(batch, ControlCodeMax);
      |         ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:117:9: error: ‘intrinsics’ has not been declared
  117 |         intrinsics::m128i isComplex = intrinsics::and128(batch, Complex);
      |         ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:119:9: error: ‘intrinsics’ has not been declared
  119 |         intrinsics::m128i testPack = intrinsics::or128(isControl, isComplex);
      |         ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:120:31: error: ‘intrinsics’ has not been declared
  120 |         if (int const check = intrinsics::movemask_epi8(testPack); check != 0)
      |                               ^~~~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:120:57: error: ‘testPack’ was not declared in this scope
  120 |         if (int const check = intrinsics::movemask_epi8(testPack); check != 0)
      |                                                         ^~~~~~~~
/build/libunicode/src/libunicode/src/libunicode/scan.cpp:126:25: error: ‘intrinsics’ has not been declared
  126 |         input += sizeof(intrinsics::m128i);
      |                         ^~~~~~~~~~

Link: https://archriscv.felixc.at/.status/log.htm?url=logs/libunicode/libunicode-0.6.0-2.log

[Yaraslaut]

Hi, unfortunately cmake does not provide built-in way to check arhitecture, and at the moment you need to disable explicitly simd usage in libunicode with cmake flag -DLIBUNICODE_SIMD_IMPLEMENTATION=none
In the future we want to add vector extenstion riscv usage, but for now we do not support simd for riscv

[Cryolitia]

Thanks so much for your response!

I would like to know one more not too related thing. If I compile it with SIMD enabled, what would happened while running it on a x86_64-v1 hardware. It's important for us distros maintainers, because most distros' package baseline is x86_64-v1, we would like to promise its availability on it, as a result of that SIMD is enabled by default that some distros may not notice it.

---

update:

cmake does not provide built-in way to check arhitecture

Could we use https://cmake.org/cmake/help/latest/variable/CMAKE_SYSTEM_PROCESSOR.html

[Yaraslaut]

Yes, we can try to check if during cmake configuration.
As for the SIMD support, at the moment intrinsics are using SSE2, so x86_64-v1, in the future this usage will be preserved and ideally checked at run-time which SIMD implementation we can use (#108)

[christianparpart]

@Yaraslaut we should be able to runtime detect architecture by using uname command line tool on UNIX like systems.

Otherwise, shouldn't something like this work as well?

if(CMAKE_SYSTEM_PROCESSOR STREQUAL "riscv64gc")
    set(LIBUNICODE_SIMD_IMPLEMENTATION none) # currently unsupported on risckv64gc
endif()

[Cryolitia]

if(CMAKE_SYSTEM_PROCESSOR STREQUAL "riscv64gc")

s/riscv64gc/riscv64/g :)

[christianparpart]

if(CMAKE_SYSTEM_PROCESSOR STREQUAL "riscv64gc")

s/riscv64gc/riscv64/g :)

I just copy'n'pasted the word from the title. I don't have any RISCV experience nor access. If that works, we can gladly add it to the CMakeLists.txt. Could you confirm this then?

[Cryolitia]

Sorry for lont time AFK.

I have create a PR: #110