From a0d464cbf74a60e5e53edbc19333aebd6fcbba1b Mon Sep 17 00:00:00 2001
From: kilyanni <github@nkilian.org>
Date: Tue, 21 Apr 2026 03:43:48 +0200
Subject: [PATCH] intel-oneapi.base: add stdenv

---
 .../libraries/intel-oneapi/base.nix           |  3 +
 .../libraries/intel-oneapi/stdenv.nix         | 58 +++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 pkgs/development/libraries/intel-oneapi/stdenv.nix

diff --git a/pkgs/development/libraries/intel-oneapi/base.nix b/pkgs/development/libraries/intel-oneapi/base.nix
index 5d4c6fc28e67..90bc8e0a2617 100644
--- a/pkgs/development/libraries/intel-oneapi/base.nix
+++ b/pkgs/development/libraries/intel-oneapi/base.nix
@@ -1,5 +1,6 @@
 {
   lib,
+  callPackage,
   fetchurl,
   zlib,
   rdma-core,
@@ -189,6 +190,8 @@ intel-oneapi.mkIntelOneApi (finalAttrs: {
     downloadPage = "https://www.intel.com/content/www/us/en/developer/tools/oneapi/base-toolkit-download.html?packages=oneapi-toolkit&oneapi-toolkit-os=linux&oneapi-lin=offline";
   };
 
+  passthru.stdenv = callPackage ./stdenv.nix { kit = intel-oneapi.base; };
+
   passthru.tests = {
     mkl-libs = stdenv.mkDerivation {
       name = "intel-oneapi-test-mkl-libs";
diff --git a/pkgs/development/libraries/intel-oneapi/stdenv.nix b/pkgs/development/libraries/intel-oneapi/stdenv.nix
new file mode 100644
index 000000000000..f813889df3e8
--- /dev/null
+++ b/pkgs/development/libraries/intel-oneapi/stdenv.nix
@@ -0,0 +1,58 @@
+{
+  kit,
+  stdenvNoCC,
+  stdenv,
+  overrideCC,
+  wrapCCWith,
+}:
+let
+  unwrappedCC = stdenvNoCC.mkDerivation {
+    name = "intel-oneapi-cc-unwrapped";
+    dontUnpack = true;
+
+    # Note: use a wrapper script, not symlinks. The compiler inspects argv[0]
+    #       to decide how to behave, so it must see itself invoked as
+    #       icx/icpx. Through a symlink it would see clang/clang++ and
+    #       select the wrong behavior.
+    installPhase = ''
+      mkdir -p $out/bin
+
+      cat > $out/bin/clang++ << 'EOF'
+      #!/bin/sh
+      exec ${kit}/compiler/latest/bin/icpx "$@"
+      EOF
+      chmod +x $out/bin/clang++
+
+      cat > $out/bin/clang << 'EOF'
+      #!/bin/sh
+      exec ${kit}/compiler/latest/bin/icx "$@"
+      EOF
+      chmod +x $out/bin/clang
+    '';
+
+    passthru.isClang = true;
+
+    # icpx rejects these flags for the SPIR-V device target (spir64-unknown-unknown).
+    hardeningUnsupportedFlags = [
+      "zerocallusedregs"
+      "pacret"
+      "shadowstack"
+    ];
+  };
+
+  wrappedCC = wrapCCWith {
+    cc = unwrappedCC;
+    extraPackages = [ kit ];
+    extraBuildCommands = ''
+      # Consumers expect the icpx/icx names and might reject clang++/clang.
+      ln -s $out/bin/clang++ $out/bin/icpx
+      ln -s $out/bin/clang   $out/bin/icx
+
+      echo "export CXX=\"$out/bin/icpx\"" >> $out/nix-support/setup-hook
+      echo "export CC=\"$out/bin/icx\"" >> $out/nix-support/setup-hook
+
+      echo "export ONEAPI_ROOT=\"${kit}\"" >> $out/nix-support/setup-hook
+    '';
+  };
+in
+overrideCC stdenv wrappedCC