From 8e52da0857a94511fe4fac7af6cfce6625750a11 Mon Sep 17 00:00:00 2001
From: pongo1231 <pongo1999712@gmail.com>
Date: Thu, 23 Jan 2025 22:53:51 +0100
Subject: [PATCH] wicked_kernel: add optimization flags & use clang

---
 modules/wicked_kernel.nix | 50 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 6 deletions(-)

diff --git a/modules/wicked_kernel.nix b/modules/wicked_kernel.nix
index e99c86f..8c86dd5 100644
--- a/modules/wicked_kernel.nix
+++ b/modules/wicked_kernel.nix
@@ -14,10 +14,10 @@
   nixpkgs.overlays = [
     (final: prev: {
       linuxPackages_wicked = final.kernel.linuxPackages_latest.extend (finalAttrs: prevAttrs: {
-        /*kernel = prevAttrs.kernel.override (prevAttrs': {
+        kernel = prevAttrs.kernel.override (prevAttrs': {
           #kernelPatches = builtins.filter (x: !lib.hasPrefix "netfilter-typo-fix" x.name) prevAttrs'.kernelPatches;
-          ignoreConfigErrors = true;
-          argsOverride =
+          #ignoreConfigErrors = true;
+          /*argsOverride =
             let
               version = "6.13-rc7";
             in
@@ -33,8 +33,8 @@
                 url = "https://git.kernel.org/torvalds/t/linux-${version}.tar.gz";
                 hash = "";
               };*/
-        /*};
-        });*/
+          #};
+        });
 
         xpadneo = prevAttrs.xpadneo.overrideAttrs (finalAttrs': prevAttrs': {
           src = final.fetchFromGitHub {
@@ -58,7 +58,43 @@
   ];
 
   boot = {
-    kernelPackages = pkgs.linuxPackages_wicked;
+    kernelPackages =
+      let
+        stdenvLLVM =
+          let
+            llvmPin = pkgs.buildPackages.llvmPackages.override {
+              bootBintools = null;
+              bootBintoolsNoLibc = null;
+            };
+
+            stdenv' = pkgs.overrideCC llvmPin.stdenv llvmPin.clangUseLLVM;
+          in
+          stdenv' // {
+            mkDerivation = args: stdenv'.mkDerivation (args // {
+              # INFO: This line may seem useless, since we already have lld coming
+              # from clangUseLLVM, but it isn't.
+              # The lld provided is wrapped "llvm-binutils-wrapper" and will _NOT_
+              # work. Adding lld here manually override that one, and works around the
+              # issue. The real solution here is to either:
+              # 1. Figure out a way to force the usage of the unwrapped bintools
+              # 2. Fix our lld wrapper
+              nativeBuildInputs = (args.nativeBuildInputs or [ ])
+              ++ (with llvmPin; [ lld ]);
+            });
+          };
+
+        makeLTO = k:
+          k.override {
+            stdenv = stdenvLLVM;
+            extraMakeFlags = k.extraMakeFlags ++ [ "LLVM=1" "LLVM_IAS=1" ];
+            argsOverride.structuredExtraConfig =
+              with lib.kernel; k.structuredExtraConfig // {
+                LTO_NONE = no;
+                LTO_CLANG_FULL = yes;
+              };
+          };
+      in
+      makeLTO pkgs.linuxPackages_wicked.kernel;
 
     kernelPatches =
       let
@@ -75,6 +111,8 @@
           patch = patch /linux/6.13/cachyos.patch;
           extraConfig = ''
             AMD_PRIVATE_COLOR y
+            X86_64_VERSION 3
+            CC_OPTIMIZE_FOR_PERFORMANCE_O3 y
           '';
         }
         /*{