From 6b430a5a3f89b34e1dcf418b80f848b092070dd0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Aleix=20Bon=C3=A9?= <aleix.boneribo@bsc.es>
Date: Fri, 18 Jul 2025 18:48:22 +0200
Subject: [PATCH] Remove wrapper flags when clang called from intel

---
 pkgs/intel-oneapi/patch_intel.nix |  4 ++++
 pkgs/llvm-ompss2/default.nix      | 19 ++++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/pkgs/intel-oneapi/patch_intel.nix b/pkgs/intel-oneapi/patch_intel.nix
index ef95d55..2bff369 100644
--- a/pkgs/intel-oneapi/patch_intel.nix
+++ b/pkgs/intel-oneapi/patch_intel.nix
@@ -147,6 +147,10 @@ stdenvNoCC.mkDerivation (finalAttrs: {
         ln -s $out/bin/icpx $out/bin/c++
         ln -s $out/bin/icx  $out/bin/cc
 
+        # Use this to detect when a compiler subprocess is called
+        # from icpx (--fsycl-host-compiler)
+        echo 'export "NIX_CC_WRAPPER_INTEL=1"' >> $out/nix-support/cc-wrapper-hook
+
         sed -i 's/.*isCxx=0/isCxx=1/' $out/bin/icpx
 
         # oneMath looks for sycl libraries in bin/../lib
diff --git a/pkgs/llvm-ompss2/default.nix b/pkgs/llvm-ompss2/default.nix
index 43f7c13..cc0db2c 100644
--- a/pkgs/llvm-ompss2/default.nix
+++ b/pkgs/llvm-ompss2/default.nix
@@ -3,6 +3,7 @@
 , lib
 , gcc
 , clangOmpss2Unwrapped
+, writeShellScript
 , openmp ? null
 , wrapCCWith
 , llvmPackages_latest
@@ -37,6 +38,19 @@ let
   inherit gcc;
   cc = clangOmpss2Unwrapped;
   gccVersion = with versions; let v = gcc.version; in concatStringsSep "." [(major v) (minor v) (patch v)];
+
+  resetIntelCCFlags = let tconf = builtins.replaceStrings ["-"] ["_"] targetConfig;
+  in writeShellScript "remove-intel.sh" ''
+    if [ "''${NIX_CC_WRAPPER_INTEL:-0}" = 1 ]; then
+      unset NIX_CFLAGS_COMPILE_${tconf}
+      unset NIX_CC_WRAPPER_FLAGS_SET_${tconf}
+
+      if (( "${NIX_DEBUG:-0}" >= 1 )); then
+        echo "ompss2: cleaned NIX_CFLAGS_COMPILE_${tconf} (invokation from intel compiler detected)"
+      fi
+    fi
+  '';
+
 in wrapCCWith {
   inherit cc bintools;
   # extraPackages adds packages to depsTargetTargetPropagated
@@ -61,7 +75,10 @@ in wrapCCWith {
 
     wrap clang++  $wrapper $ccPath/clang++
 
-  '' + optionalString (openmp != null) ''
+    sed -i 's|# Flirting.*|source ${resetIntelCCFlags}\n\n&|' $out/bin/clang
+    sed -i 's|# Flirting.*|&\nsource ${resetIntelCCFlags}\n\n&|' $out/bin/clang++
+
+  '' + lib.optionalString (openmp != null) ''
     echo "export OPENMP_RUNTIME=${ompname}" >> $out/nix-support/cc-wrapper-hook
   '' + optionalString (ompss2rt != null) ''
     echo "export OMPSS2_RUNTIME=${rtname}" >> $out/nix-support/cc-wrapper-hook