Source: snappy
Version: 1.3.1-2
Severity: serious
Tags: ftbfs
Justification: fails to build from source (but built successfully in the past)
X-Debbugs-Cc: debian-riscv@lists.debian.org, sramacher@debian.org
User: debian-riscv@lists.debian.org
Usertags: riscv64

Dear maintainer,

snappy FTBFS on riscv64:

/usr/bin/riscv64-linux-gnu-g++  -I/build/reproducible-path/snappy-1.3.1/build -I/build/reproducible-path/snappy-1.3.1 -g -O2 -ffile-prefix-map=/build/reproducible-path/snappy-1.3.1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -Wall -Wextra -Wno-sign-compare -fno-exceptions -O2 -g -DNDEBUG -std=gnu++17 -MD -MT CMakeFiles/snappy-static.dir/snappy.cc.o -MF CMakeFiles/snappy-static.dir/snappy.cc.o.d -o CMakeFiles/snappy-static.dir/snappy.cc.o -c /build/reproducible-path/snappy-1.3.1/snappy.cc
/usr/bin/riscv64-linux-gnu-g++ -DHAVE_CONFIG_H -Dsnappy_EXPORTS -I/build/reproducible-path/snappy-1.3.1/build -I/build/reproducible-path/snappy-1.3.1 -g -O2 -ffile-prefix-map=/build/reproducible-path/snappy-1.3.1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -Wall -Wextra -Wno-sign-compare -fno-exceptions -O2 -g -DNDEBUG -std=gnu++17 -fPIC -MD -MT CMakeFiles/snappy.dir/snappy.cc.o -MF CMakeFiles/snappy.dir/snappy.cc.o.d -o CMakeFiles/snappy.dir/snappy.cc.o -c /build/reproducible-path/snappy-1.3.1/snappy.cc
/build/reproducible-path/snappy-1.3.1/snappy.cc: In function ‘void snappy::MemCopy64(char*, const void*, size_t)’:
/build/reproducible-path/snappy-1.3.1/snappy.cc:1281:28: error: built-in function ‘__riscv_vsetvl_e8m2(remaining_bytes)’ requires the ‘v’ ISA extension
 1281 |     size_t vl = VSETVL_E8M2(remaining_bytes);
/build/reproducible-path/snappy-1.3.1/snappy.cc:1283:33: error: this operation requires the RVV ISA extension
 1283 |     vuint8m2_t vec = VLE8_V_U8M2(src_ptr, vl);
/build/reproducible-path/snappy-1.3.1/snappy.cc:1283:33: note: you can enable RVV using the command-line option ‘-march’, or by using the ‘target’ attribute or pragma
/build/reproducible-path/snappy-1.3.1/snappy.cc:1283:33: error: built-in function ‘__riscv_vle8_v_u8m2(src_ptr, vl)’ requires the ‘v’ ISA extension
/build/reproducible-path/snappy-1.3.1/snappy.cc:1285:16: error: built-in function ‘__riscv_vse8_v_u8m2(dst_ptr, vec, vl)’ requires the ‘v’ ISA extension
 1285 |     VSE8_V_U8M2(dst_ptr, vec, vl);
make[3]: *** [CMakeFiles/snappy.dir/build.make:124: CMakeFiles/snappy.dir/snappy.cc.o] Error 1

See
https://buildd.debian.org/status/fetch.php?pkg=snappy&arch=riscv64&ver=1.3.1-2&stamp=1790060158&raw=0
for details.

Cheers

  -- Performing Test SNAPPY_RVV_1
  -- Performing Test SNAPPY_RVV_1 - Success


Which has an interesting cause:

$ cat test.cc
  #include <riscv_vector.h>
  #include <stdint.h>
  #include <stddef.h>
  int main() {
    uint8_t val = 3, dup[8];
    size_t vl = __riscv_vsetvl_e8m1(8);
    vuint8m1_t v = __riscv_vmv_v_x_u8m1(val, vl);
    return 0;
  }
$ g++ -Wall test.cc
test.cc: In function 'int main()':
test.cc:5:22: warning: unused variable 'dup' [-Wunused-variable]
    5 |     uint8_t val = 3, dup[8];
      |                      ^~~
test.cc:7:16: warning: unused variable 'v' [-Wunused-variable]
    7 |     vuint8m1_t v = __riscv_vmv_v_x_u8m1(val, vl);
      |                ^
test.cc:6:36: error: built-in function '__riscv_vsetvl_e8m1(8)' requires the 'v' ISA extension
    6 |     size_t vl = __riscv_vsetvl_e8m1(8);
      |                 ~~~~~~~~~~~~~~~~~~~^~~
test.cc:7:40: error: this operation requires the RVV ISA extension
    7 |     vuint8m1_t v = __riscv_vmv_v_x_u8m1(val, vl);
      |                    ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~
test.cc:7:40: note: you can enable RVV using the command-line option '-march', or by using the 'target' attribute or pragma
test.cc:7:40: error: built-in function '__riscv_vmv_v_x_u8m1(val, vl)' requires the 'v' ISA extension
(sid_riscv64-dchroot)bunk@ricci:~/build$ g++ -Wall -O2 test.cc
test.cc: In function 'int main()':
test.cc:5:22: warning: unused variable 'dup' [-Wunused-variable]
    5 |     uint8_t val = 3, dup[8];
      |                      ^~~
test.cc:7:16: warning: unused variable 'v' [-Wunused-variable]
    7 |     vuint8m1_t v = __riscv_vmv_v_x_u8m1(val, vl);
      |                ^
$


Removing the SNAPPY_RVV_1 block from CMakeLists.txt works around this issue.

cu
Adrian

Which might be the best option until the GCC bug[1] is fixed.

cu
Adrian

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127553

Dear maintainer,

I've prepared an NMU for snappy (versioned as 1.3.1-2.1) and uploaded
it to DELAYED/7. Please feel free to tell me if I should cancel it.

cu
Adrian

We believe that the bug you reported is fixed in the latest version of
snappy, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1148704@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Laszlo Boszormenyi (GCS) <gcs@debian.org> (supplier of updated snappy package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Fri, 25 Sep 2026 16:52:44 +0200
Source: snappy
Architecture: source
Version: 1.3.1-3
Distribution: unstable
Urgency: medium
Maintainer: Laszlo Boszormenyi (GCS) <gcs@debian.org>
Changed-By: Laszlo Boszormenyi (GCS) <gcs@debian.org>
Closes: 1148704
Changes:
 snappy (1.3.1-3) unstable; urgency=medium
 .
   [ Adrian Bunk ]
   * Workaround RVV detection GCC bug (closes: #1148704).
Checksums-Sha1:
 5b39e1e2dd4e82da36a7febab4ac8e83b6fd1025 1842 snappy_1.3.1-3.dsc
 756b803a8a652a88d6c1f800f4724e1cfa46c030 16900 snappy_1.3.1-3.debian.tar.xz
Checksums-Sha256:
 a5ce687bd5a034096d0447355b99b52d1a30c3773043cb4aeb5b25f4da65d4da 1842 snappy_1.3.1-3.dsc
 2ebc1f4c0c2b6ad9f197db2ebca340ad762090a133270be5ded96a021969123e 16900 snappy_1.3.1-3.debian.tar.xz
Files:
 ebb2d748777f88af54717746e5e50da7 1842 libs optional snappy_1.3.1-3.dsc
 08a8caf18e5ebd5b964837dd048626a9 16900 libs optional snappy_1.3.1-3.debian.tar.xz
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