Arch Linux User Repository

@niklasf

The stockfish Makefile chooses what compiler to use by reading the environment variable COMP instead of reading CC or CXX. For those that prefer to use Clang as their default compiler, could the following change be considered?

diff --git a/PKGBUILD b/PKGBUILD
index 18742f6..74665c6 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -73,7 +73,17 @@ build() {
     _arch=x86-64
   fi

-  make ARCH="$_arch" profile-build
+  if [[ "$CC" = "gcc" ]]
+  then
+    _COMP=gcc
+  elif [[ "$CC" = "clang" ]]
+  then
+    _COMP=clang
+  else
+    _COMP=
+  fi
+
+  COMP=${_COMP} make ARCH="$_arch" profile-build
 }

 package() {

This will set the variable COMP to either gcc or clang depending on which compiler is set for CC. As a fall back, the variable will be set to blank, in which case the Makefile will choose GCC by default.

Hello, I was playing around with stockfish, and noticed that there is a new update upstream released a few hours ago. Here is a link to github update with the patch . Most specifically, the commit to use is this .

@HurricanePootis: Thanks, fixed.

This package does not comply with an SPDX compliant license(), nor does it list gcc-libs as a depend. Besides that, it's a swag package. I have left a patch below:

diff --git a/PKGBUILD b/PKGBUILD
index f361d4e..7c514d5 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -16,8 +16,8 @@ epoch=1
 pkgdesc="A strong UCI chess engine"
 arch=('x86_64' 'i686' 'armv7h' 'aarch64')
 url="https://stockfishchess.org/"
-license=('GPL3')
-depends=('glibc')
+license=('GPL-3.0-or-later')
+depends=('glibc' 'gcc-libs')
 # Check EvalFileDefaultName{Big,Small} in src/evaluate.h and change accordingly
 _net_name_big=('b1a57edbea57')
 _net_name_small=('baff1ede1f90')

@bagasdotme: Thanks, applied.

@xiota: Unfortunately Stockfish-specific arguments/flags are required. The performance difference increased a lot after neural networks were introduced. For example, x86-64-bmi2 vs x86-64 is usually more than twice as fast in terms of nps.

@niklasf: Instead of downloading default neural nets when building (and thus require wget/curl in depends array, you can list them in sources array), just like in berserk PKGBUILD:

diff --git a/PKGBUILD b/PKGBUILD
index 0203dd4baf..a39c3b39d4 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -10,15 +10,29 @@

 pkgname=stockfish
 pkgver=16.1
-pkgrel=1
+pkgrel=2
 epoch=1
 pkgdesc="A strong UCI chess engine"
 arch=('x86_64' 'i686' 'armv7h' 'aarch64')
 url="https://stockfishchess.org/"
 license=('GPL3')
 depends=('glibc')
-source=("$pkgname-$pkgver.zip::https://github.com/official-stockfish/Stockfish/archive/sf_$pkgver.zip")
-sha512sums=('bfaa5c644d2acb8538b1a2c72fdf58c6b0ba6cbb3a4e1a335391faa1529f1069eca888295bd4eef0e887860185a3e0e18529ab609829738c420a0c810be5cca4')
+# Neural nets used for this particular release, to evaluate positions. Each
+# release may use different ones, thus check EvalFileDefaultName{Big,Small} macros
+# in src/evaluate.h and change accordingly.
+_net_name_big=('b1a57edbea57')
+_net_name_small=('baff1ede1f90')
+source=("$pkgname-$pkgver.zip::https://github.com/official-stockfish/Stockfish/archive/sf_$pkgver.zip"
+  "https://tests.stockfishchess.org/api/nn/nn-${_net_name_big}.nnue"
+  "https://tests.stockfishchess.org/api/nn/nn-${_net_name_small}.nnue")
+sha512sums=('bfaa5c644d2acb8538b1a2c72fdf58c6b0ba6cbb3a4e1a335391faa1529f1069eca888295bd4eef0e887860185a3e0e18529ab609829738c420a0c810be5cca4'
+            'de2141ba301dd4da0cfa5d3a8f3574fa0ac9b24915fa1802654ad8baf274157feb1fd0ce96aae3893b789a1bb1df8eccdb4a5a331756802bebde3c4d1db5f1de'
+            '56358da4810a2bf5b903668d8243ec888a0a64302a893207074b3f1644c9877ddd4557303f025eabcc6e0f7b31af42c1265ba2fd34209df9dd0ea205d4f4a8e9')
+
+prepare() {
+  ln -sf "${srcdir}/nn-${_net_name_big}.nnue" "Stockfish-sf_${pkgver}/src"
+  ln -sf "${srcdir}/nn-${_net_name_small}.nnue" "Stockfish-sf_${pkgver}/src"
+}

 build() {
   cd "Stockfish-sf_${pkgver}/src"

CPU detection is unnecessary when FLAGS are set correctly in makepkg.conf (user responsibility).

From benchmarks I ran a while back, the performance benefit wasn't very big, about the same as using clang instead of gcc.

@xiota: Sorry, I understand that doing build-time CPU feature detection is essentially broken, but the regression on modern hardware would be so huge that I don't just want to remove it without replacement. Maybe we could build for all applicable targets and have a small wrapper script doing feature detection at runtime?

Please remove CPU detection code. It produces binaries that crash when used on a different computer. I understand that the upstream Makefile also tries to detect CPU.

Here is a PKGBUILD that bypasses CPU detection and respects CXXFLAGS set in makepkg.conf

@buzo: Thanks. Removed those.

@SandaruKasa: There is now an official solution (https://github.com/official-stockfish/Stockfish/commit/a4d18d23a9f7626234fcfbb6b23b3d0b8d1a9441). So I backported this, replacing the workaround.