From 3697ddeabe2c51a868a2b1d1f2626f7778d673b4 Mon Sep 17 00:00:00 2001
From: Artturin <Artturin@artturin.com>
Date: Wed, 15 Feb 2023 00:12:41 +0200
Subject: [PATCH 1/3] bintools-wrapper: wrap all 'ld.*'

allows using wrapBintoolsWith with all linkers

```
$ nix build ".#binutils"
$ ls ./result/bin/ld*
./result/bin/ld*  ./result/bin/ld.bfd*  ./result/bin/ld.gold*

$ nix build "nixpkgs#binutils"
$ ls ./result/bin/ld*
./result/bin/ld*  ./result/bin/ld.bfd* ./result/bin/ld.gold*
```
---
 pkgs/build-support/bintools-wrapper/default.nix | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/pkgs/build-support/bintools-wrapper/default.nix b/pkgs/build-support/bintools-wrapper/default.nix
index 45ae3eba9b44..05b5a3732580 100644
--- a/pkgs/build-support/bintools-wrapper/default.nix
+++ b/pkgs/build-support/bintools-wrapper/default.nix
@@ -192,10 +192,9 @@ stdenv.mkDerivation {
       unset ldInner
     '') + ''
 
-      for variant in ld.gold ld.bfd ld.lld; do
-        local underlying=$ldPath/${targetPrefix}$variant
-        [[ -e "$underlying" ]] || continue
-        wrap ${targetPrefix}$variant ${./ld-wrapper.sh} $underlying
+      for variant in $ldPath/${targetPrefix}ld.*; do
+        basename=$(basename "$variant")
+        wrap $basename ${./ld-wrapper.sh} $variant
       done
     '';
 

From b5abc3d0907c7c5d70479c60ff7f1cf262ead4c8 Mon Sep 17 00:00:00 2001
From: Artturin <Artturin@artturin.com>
Date: Fri, 17 Feb 2023 04:56:48 +0200
Subject: [PATCH 2/3] bintools-wrapper: dont wrap ld if it doesn't exist

not all linkers have a ld binary in bin

also note the '${ld:-}' which allows users to set the ld path with a env
var

> '${foo:-val}' $foo, or val if unset (or null)
---
 pkgs/build-support/bintools-wrapper/default.nix | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pkgs/build-support/bintools-wrapper/default.nix b/pkgs/build-support/bintools-wrapper/default.nix
index 05b5a3732580..15d81e852f83 100644
--- a/pkgs/build-support/bintools-wrapper/default.nix
+++ b/pkgs/build-support/bintools-wrapper/default.nix
@@ -184,7 +184,9 @@ stdenv.mkDerivation {
       done
 
     '' + (if !useMacosReexportHack then ''
-      wrap ${targetPrefix}ld ${./ld-wrapper.sh} ''${ld:-$ldPath/${targetPrefix}ld}
+      if [ -e ''${ld:-$ldPath/${targetPrefix}ld} ]; then
+        wrap ${targetPrefix}ld ${./ld-wrapper.sh} ''${ld:-$ldPath/${targetPrefix}ld}
+      fi
     '' else ''
       ldInner="${targetPrefix}ld-reexport-delegate"
       wrap "$ldInner" ${./macos-sierra-reexport-hack.bash} ''${ld:-$ldPath/${targetPrefix}ld}

From 299a7bd35e552fe6e444096658d7e9ebafb038af Mon Sep 17 00:00:00 2001
From: Artturin <Artturin@artturin.com>
Date: Fri, 17 Feb 2023 05:18:19 +0200
Subject: [PATCH 3/3] stdenvAdapters: add useMoldLinker

---
 pkgs/stdenv/adapters.nix | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/pkgs/stdenv/adapters.nix b/pkgs/stdenv/adapters.nix
index 42d19a0fad4b..2ea9a359f07b 100644
--- a/pkgs/stdenv/adapters.nix
+++ b/pkgs/stdenv/adapters.nix
@@ -189,6 +189,28 @@ rec {
       });
     });
 
+  useMoldLinker = stdenv: let
+    bintools = stdenv.cc.bintools.override {
+      extraBuildCommands = ''
+        wrap ld.mold ${../build-support/bintools-wrapper/ld-wrapper.sh} ${pkgs.mold}/bin/ld.mold
+        wrap ld ${../build-support/bintools-wrapper/ld-wrapper.sh} ${pkgs.mold}/bin/ld.mold
+      '';
+    };
+  in stdenv.override (old: {
+    cc = stdenv.cc.override {
+      inherit bintools;
+    };
+    allowedRequisites =
+      lib.mapNullable (rs: rs ++ [ bintools pkgs.mold (lib.getLib pkgs.mimalloc) (lib.getLib pkgs.openssl) ]) (stdenv.allowedRequisites or null);
+      # gcc >12.1.0 supports '-fuse-ld=mold'
+      # the wrap ld above in bintools supports gcc <12.1.0 and shouldn't harm >12.1.0
+    # https://github.com/rui314/mold#how-to-use
+    } // lib.optionalAttrs (stdenv.cc.isClang || (stdenv.cc.isGNU && lib.versionAtLeast stdenv.cc.version "12")) {
+    mkDerivationFromStdenv = extendMkDerivationArgs old (args: {
+      NIX_CFLAGS_LINK = toString (args.NIX_CFLAGS_LINK or "") + " -fuse-ld=mold";
+    });
+  });
+
 
   /* Modify a stdenv so that it builds binaries optimized specifically
      for the machine they are built on.