swiftPackages_ng.swift: include the stdlib in the toolchain

pkgs/development/compilers/swift_ng/by-name/sw/swift/package.nix

@@ -3,7 +3,9 @@
   apple-sdk_14,
   apple-sdk_26,
   llvmPackages_upstream,
+  patchelf,
   stdenv,
+  stdlib,
   swift-corelibs-foundation,
   swift-corelibs-libdispatch,
   swift-driver,
@@ -29,6 +31,11 @@ let
       swiftc.out
       swiftc.dev
     ]
+    ++ lib.optionals (stdlib != null) [
+      stdlib.dev
+      stdlib.out
+      swiftc.dev
+    ]
     ++ lib.optionals (swift-driver != null) [
       swift-driver.out
       swift-driver.dev
@@ -87,6 +94,10 @@ stdenv.mkDerivation (finalAttrs: {
   # Will effectively be `buildInputs` when swift is put in `nativeBuildInputs`.
   depsTargetTargetPropagated =
     lib.optionals stdenv.targetPlatform.isDarwin [ propagated-sdk ]
+    ++ lib.optionals (stdlib != null) [
+      # Propagate the stdlib to make sure the linker wrapper will pick up the dynamic and static libraries.
+      stdlib
+    ]
     ++ lib.optionals (!stdenv.hostPlatform.isDarwin) (
       lib.optionals (swift-corelibs-libdispatch != null) [
         swift-corelibs-libdispatch-no-overlay.out
@@ -152,6 +163,16 @@ stdenv.mkDerivation (finalAttrs: {
 
     recordPropagatedDependencies
 
+    ${lib.optionalString (stdlib != null) ''
+      # Can’t use `replaceVars` because it needs to substitute $out.
+      substitute ${./setup-hook.sh} "$out/nix-support/setup-hook" \
+        --replace-fail @patchelf@ ${lib.escapeShellArg (lib.getExe patchelf)} \
+        --replace-fail @objdump@ ${lib.escapeShellArg (lib.getExe' llvmPackages_upstream.llvm "llvm-objdump")} \
+        --replace-fail @install_name_tool@ ${lib.escapeShellArg (lib.getExe' llvmPackages_upstream.llvm "llvm-install-name-tool")} \
+        --replace-fail @stdlibPath@ ${lib.escapeShellArg stdlib.out} \
+        --replace-fail @swiftPath@ "$out" \
+        --replace-fail @swiftPlatform@ ${stdenv.hostPlatform.swift.platform}
+    ''}
     chmod -R u-w "$out/bin" "$out/lib" "$out/nix-support"
 
     # Have to invoke manually because of `buildCommand`.

pkgs/development/compilers/swift_ng/by-name/sw/swift/setup-hook.sh

@@ -0,0 +1,30 @@
+fixSwiftRpathsIn() {
+    local dir=$1
+
+    local swiftPath=@swiftPath@/lib
+    local swiftPathForPlatform=@swiftPath@/lib/swift/@swiftPlatform@
+    local stdlibPath=@stdlibPath@/lib
+
+    local f
+    while IFS= read -d "" f; do
+        if LC_ALL=C isMachO "$f"; then
+            IFS= readarray -d $'\n' -t rpaths < <(@objdump@ --macho --rpaths "$f" | tail -n +2)
+            for oldPath in "${rpaths[@]}"; do
+                local newPath=${oldPath/$swiftPathForPlatform/$stdlibPath}
+                newPath=${newPath/$swiftPath/$stdlibPath}
+                if [ "$newPath" != "$oldPath" ]; then
+                    @install_name_tool@ "$f" -rpath "$oldPath" "$newPath"
+                fi
+            done
+        elif isELF "$f"; then
+            local oldRpaths=$(@patchelf@ --print-rpath "$f")
+            local newRpaths=${oldRpaths/$swiftPathForPlatform/$stdlibPath}
+            newRpaths=${newRpaths/$swiftPath/$stdlibPath}
+            if [ "$newRpaths" != "$oldRpaths" ]; then
+                @patchelf@ --set-rpath "$newRpaths" "$f"
+            fi
+        fi
+    done < <(find "$dir" -type f -print0)
+}
+
+fixupOutputHooks+=('fixSwiftRpathsIn $prefix')

pkgs/top-level/swift-packages.nix

@@ -31,6 +31,7 @@ let
         );
       }
       // lib.optionalAttrs (bootstrapStage != 2) {
+        stdlib = null; # Have the bootstrap compiler use its own build of the stdlib.
         swift-driver = prev.swift-driver.overrideAttrs (old: {
           pname = "early-${old.pname}";
         });