lib.systems: introduce libcxx, unwinderlib, and rtlib

lib/systems/default.nix

@@ -105,12 +105,17 @@ let
         "clang"
       else "gcc";
 
-      bintools = if final.toolchain == "bintools" then
+      bintools = if final.toolchain == "llvm" then
         "llvm"
       else if final.toolchain == "apple" then
         "apple"
       else "gnu";
 
+      libcxx =
+        /**/ if final.toolchain == "llvm" then "libcxx"
+        else if final.toolchain == "gnu" then "libstdcxx"
+        else null;
+
       libc =
         /**/ if final.isDarwin                then "libSystem"
         else if final.isMinGW                 then "msvcrt"
@@ -129,6 +134,17 @@ let
         else if final.isNone                  then "newlib"
         # TODO(@Ericson2314) think more about other operating systems
         else                                     "native/impure";
+
+      unwinderlib =
+        /**/ if final.toolchain == "llvm" then "libunwinder"
+        else if final.toolchain == "gnu" then "libgcc_s"
+        else null;
+
+      rtlib =
+        /**/ if final.toolchain == "llvm" then "compiler-rt"
+        else if final.toolchain == "gnu" then "libgcc"
+        else null;
+
       # Choose what linker we wish to use by default. Someday we might also
       # choose the C compiler, runtime library, C++ standard library, etc. in
       # this way, nice and orthogonally, and deprecate `useLLVM`. But due to

pkgs/build-support/cc-wrapper/default.nix

@@ -120,8 +120,8 @@ let
 
   useGccForLibs = useCcForLibs
     && libcxx == null
+    && targetPlatform.rtlib == "libgcc"
     && !targetPlatform.isDarwin
-    && !(targetPlatform.toolchain == "llvm")
     && !(targetPlatform.useAndroidPrebuilt or false)
     && !(targetPlatform.isiOS or false)
     && gccForLibs != null;
@@ -514,7 +514,7 @@ stdenvNoCC.mkDerivation {
     + optionalString (isClang
                       && targetPlatform.isLinux
                       && !(targetPlatform.useAndroidPrebuilt or false)
-                      && !(targetPlatform.toolchain == "llvm")
+                      && targetPlatform.rtlib == "libgcc"
                       && gccForLibs != null) (''
       echo "--gcc-toolchain=${gccForLibs}" >> $out/nix-support/cc-cflags
 

pkgs/by-name/cy/cyrus_sasl/package.nix

@@ -74,7 +74,7 @@ stdenv.mkDerivation rec {
       "--enable-shared"
     ]
     ++ lib.optional enableLdap "--with-ldap=${openldap.dev}"
-    ++ lib.optionals (stdenv.targetPlatform.toolchain == "llvm") [
+    ++ lib.optionals (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) [
       "--disable-sample"
       "CFLAGS=-DTIME_WITH_SYS_TIME"
     ];

pkgs/by-name/el/elfutils/package.nix

@@ -63,7 +63,7 @@ stdenv.mkDerivation rec {
     ++ lib.optionals stdenv.hostPlatform.isMusl [ ./musl-error_h.patch ]
     # Prevent headers and binaries from colliding which results in an error.
     # https://sourceware.org/pipermail/elfutils-devel/2024q3/007281.html
-    ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") ./cxx-header-collision.patch;
+    ++ lib.optional (stdenv.hostPlatform.libcxx == "libcxx") ./cxx-header-collision.patch;
 
   postPatch =
     ''
@@ -94,7 +94,7 @@ stdenv.mkDerivation rec {
       bzip2
     ]
     ++ lib.optional enableDebuginfod pkg-config
-    ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") autoreconfHook;
+    ++ lib.optional (stdenv.hostPlatform.libcxx == "libcxx") autoreconfHook;
   buildInputs =
     [
       zlib
@@ -128,7 +128,7 @@ stdenv.mkDerivation rec {
       # Versioned symbols are nice to have, but we can do without.
       (lib.enableFeature (!stdenv.hostPlatform.isMicroBlaze) "symbol-versioning")
     ]
-    ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") "--disable-demangler"
+    ++ lib.optional (stdenv.hostPlatform.unwinderlib == "libunwind") "--disable-demangler"
     ++ lib.optionals stdenv.cc.isClang [
       "CFLAGS=-Wno-unused-private-field"
       "CXXFLAGS=-Wno-unused-private-field"

pkgs/by-name/ke/kexec-tools/package.nix

@@ -19,13 +19,17 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-Z7GsUDqt5FpU2wvHkiiogwo11dT4PO6TLP8+eoGkqew=";
   };
 
-  patches = [
-    # Use ELFv2 ABI on ppc64be
-    (fetchpatch {
-      url = "https://raw.githubusercontent.com/void-linux/void-packages/6c1192cbf166698932030c2e3de71db1885a572d/srcpkgs/kexec-tools/patches/ppc64-elfv2.patch";
-      sha256 = "19wzfwb0azm932v0vhywv4221818qmlmvdfwpvvpfyw4hjsc2s1l";
-    })
-  ] ++ lib.optional (stdenv.hostPlatform.toolchain == "llvm") ./fix-purgatory-llvm-libunwind.patch;
+  patches =
+    [
+      # Use ELFv2 ABI on ppc64be
+      (fetchpatch {
+        url = "https://raw.githubusercontent.com/void-linux/void-packages/6c1192cbf166698932030c2e3de71db1885a572d/srcpkgs/kexec-tools/patches/ppc64-elfv2.patch";
+        sha256 = "19wzfwb0azm932v0vhywv4221818qmlmvdfwpvvpfyw4hjsc2s1l";
+      })
+    ]
+    ++ lib.optional (
+      stdenv.hostPlatform.unwinderlib == "libunwind"
+    ) ./fix-purgatory-llvm-libunwind.patch;
 
   hardeningDisable = [
     "format"

pkgs/by-name/so/sourceHighlight/package.nix

@@ -62,7 +62,7 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ updateAutotoolsGnuConfigScriptsHook ];
   buildInputs =
     [ boost ]
-    ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") (
+    ++ lib.optional (stdenv.hostPlatform.rtlib == "compiler-rt") (
       llvmPackages.compiler-rt.override {
         doFakeLibgcc = true;
       }
@@ -92,7 +92,7 @@ stdenv.mkDerivation rec {
     maintainers = with maintainers; [ SuperSandro2000 ];
   };
 }
-// lib.optionalAttrs (stdenv.targetPlatform.toolchain == "llvm") {
+// lib.optionalAttrs (stdenv.targetPlatform.rtlib == "libunwind") {
   # Force linking to "libgcc" so tests pass
   NIX_CFLAGS_COMPILE = "-lgcc";
 }

pkgs/development/libraries/libunwind/default.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation (finalAttrs: {
     hash = "sha256-rCFBHs6rCSnp5FEwbUR5veNNTqSQpFblAv8ebSPX0qE=";
   };
 
-  patches = lib.optional (stdenv.targetPlatform.toolchain == "llvm") (fetchpatch {
+  patches = lib.optional (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) (fetchpatch {
     url = "https://github.com/libunwind/libunwind/pull/770/commits/a69d0f14c9e6c46e82ba6e02fcdedb2eb63b7f7f.patch";
     hash = "sha256-9oBZimCXonNN++jJs3emp9w+q1aj3eNzvSKPgh92itA=";
   });

pkgs/development/libraries/libva/default.nix

@@ -69,7 +69,7 @@ stdenv.mkDerivation (finalAttrs: {
       {
         NIX_LDFLAGS = "--undefined-version";
       }
-    // lib.optionalAttrs (stdenv.targetPlatform.toolchain == "llvm") {
+    // lib.optionalAttrs (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) {
       NIX_CFLAGS_COMPILE = "-DHAVE_SECURE_GETENV";
     };
 

pkgs/development/libraries/openssl/default.nix

@@ -98,7 +98,8 @@ let
         ++ lib.optional static "etc";
       setOutputFlags = false;
       separateDebugInfo =
-        !stdenv.hostPlatform.isDarwin && !(stdenv.hostPlatform.toolchain == "llvm") && stdenv.cc.isGNU;
+        # Using "cc.isClang" causes infinite recursion.
+        !stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.cc != "clang" && stdenv.cc.isGNU;
 
       nativeBuildInputs =
         lib.optional (!stdenv.hostPlatform.isWindows) makeBinaryWrapper

pkgs/development/libraries/quictls/default.nix

@@ -64,7 +64,7 @@ stdenv.mkDerivation rec {
 
   separateDebugInfo =
     !stdenv.hostPlatform.isDarwin &&
-    !(stdenv.hostPlatform.toolchain == "llvm") &&
+    !stdenv.cc.isClang &&
     stdenv.cc.isGNU;
 
   # TODO(@Ericson2314): Improve with mass rebuild

pkgs/development/libraries/silgraphite/graphite2.nix

@@ -32,7 +32,7 @@ stdenv.mkDerivation (finalAttrs: {
   ];
   buildInputs =
     [ freetype ]
-    ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") (
+    ++ lib.optional (stdenv.hostPlatform.rtlib == "compiler-rt") (
       llvmPackages.compiler-rt.override {
         doFakeLibgcc = true;
       }

pkgs/development/python-modules/jedi/default.nix

@@ -53,7 +53,7 @@ buildPythonPackage rec {
       # AssertionError: assert 'foo' in ['setup']
       "test_init_extension_module"
     ]
-    ++ lib.optionals (stdenv.targetPlatform.toolchain == "llvm") [
+    ++ lib.optionals (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) [
       # InvalidPythonEnvironment: The python binary is potentially unsafe.
       "test_create_environment_executable"
       # AssertionError: assert ['', '.1000000000000001'] == ['', '.1']

pkgs/development/python-modules/mako/default.nix

@@ -61,7 +61,7 @@ buildPythonPackage rec {
       "test_bytestring_passthru"
     ]
     # https://github.com/sqlalchemy/mako/issues/408
-    ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") "test_future_import";
+    ++ lib.optional (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) "test_future_import";
 
   meta = with lib; {
     description = "Super-fast templating language";

pkgs/os-specific/linux/systemd/default.nix

@@ -375,7 +375,7 @@ stdenv.mkDerivation (finalAttrs: {
     ++ lib.optionals withPasswordQuality [ libpwquality ]
     ++ lib.optionals withQrencode [ qrencode ]
     ++ lib.optionals withLibarchive [ libarchive ]
-    ++ lib.optional (withBootloader && stdenv.targetPlatform.toolchain == "llvm") (llvmPackages.compiler-rt.override {
+    ++ lib.optional (withBootloader && stdenv.hostPlatform.rtlib == "compiler-rt") (llvmPackages.compiler-rt.override {
       doFakeLibgcc = true;
     })
   ;

pkgs/os-specific/windows/default.nix

@@ -26,7 +26,7 @@ lib.makeScope newScope (
 
     # FIXME untested with llvmPackages_16 was using llvmPackages_8
     crossThreadsStdenv = overrideCC stdenvNoLibc (
-      if stdenv.hostPlatform.toolchain == "llvm" then
+      if stdenv.cc.isClang then
         buildPackages.llvmPackages.clangNoLibcxx
       else
         buildPackages.gccWithoutTargetLibc.override (old: {

pkgs/servers/x11/xorg/overrides.nix

@@ -159,7 +159,7 @@ self: super:
     ];
     configureFlags = attrs.configureFlags or []
       ++ malloc0ReturnsNullCrossFlag
-      ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") "ac_cv_path_RAWCPP=cpp";
+      ++ lib.optional (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) "ac_cv_path_RAWCPP=cpp";
     depsBuildBuild = [
       buildPackages.stdenv.cc
     ] ++ lib.optionals stdenv.hostPlatform.isStatic [
@@ -269,7 +269,7 @@ self: super:
     '';
     configureFlags = attrs.configureFlags or []
       ++ malloc0ReturnsNullCrossFlag
-      ++ lib.optional (stdenv.targetPlatform.toolchain == "llvm") "ac_cv_path_RAWCPP=cpp";
+      ++ lib.optional (stdenv.cc.isClang && !stdenv.hostPlatform.isDarwin) "ac_cv_path_RAWCPP=cpp";
     propagatedBuildInputs = attrs.propagatedBuildInputs or [] ++ [ xorg.libSM ];
     depsBuildBuild = [ buildPackages.stdenv.cc ];
     CPP = if stdenv.hostPlatform.isDarwin then "clang -E -" else "${stdenv.cc.targetPrefix}cc -E -";

pkgs/top-level/all-packages.nix

@@ -61,15 +61,15 @@ with pkgs;
       # thing to to create an earlier thing (leading to infinite recursion) and
       # we also would still respect the stage arguments choices for these
       # things.
-      (if stdenvNoCC.hostPlatform.isDarwin || stdenvNoCC.hostPlatform.toolchain == "llvm"
+      (if stdenvNoCC.hostPlatform.cc == "clang"
        then overrideCC stdenvNoCC buildPackages.llvmPackages.clangNoCompilerRt
        else gccCrossLibcStdenv)
     else mkStdenvNoLibs stdenv;
 
   stdenvNoLibc =
     if stdenvNoCC.hostPlatform != stdenvNoCC.buildPlatform
     then
-      (if stdenvNoCC.hostPlatform.isDarwin || stdenvNoCC.hostPlatform.toolchain == "llvm"
+      (if stdenvNoCC.hostPlatform.cc == "clang"
        then overrideCC stdenvNoCC buildPackages.llvmPackages.clangNoLibc
        else gccCrossLibcStdenv)
     else mkStdenvNoLibs stdenv;
@@ -12163,7 +12163,7 @@ with pkgs;
 
   busybox = callPackage ../os-specific/linux/busybox {
     # Fixes libunwind from being dynamically linked to a static binary.
-    stdenv = if stdenv.targetPlatform.toolchain == "llvm" then
+    stdenv = if stdenv.cc.isClang && stdenv.hostPlatform.unwinderlib == "libunwind" then
       overrideCC stdenv buildPackages.llvmPackages.clangNoLibcxx
     else stdenv;
   };

pkgs/top-level/stage.nix

@@ -118,6 +118,9 @@ let
       inherit (self.pkgsBuildHost.xorg) lndir;
     };
 
+  cleanToolchain = platform: builtins.removeAttrs platform
+    [ "toolchain" "cc" "bintools" "linker" "libc" "libcxx" "unwinderlib" "rtlib" ];
+
   stdenvBootstappingAndPlatforms = self: super: let
     withFallback = thisPkgs:
       (if adjacentPackages == null then self else thisPkgs)
@@ -201,7 +204,7 @@ let
       # Bootstrap a cross stdenv using the LLVM toolchain.
       # This is currently not possible when compiling natively,
       # so we don't need to check hostPlatform != buildPlatform.
-      crossSystem = stdenv.hostPlatform // {
+      crossSystem = (cleanToolchain stdenv.hostPlatform) // {
         toolchain = "llvm";
       };
     };
@@ -215,7 +218,7 @@ let
       # Bootstrap a cross stdenv using the Aro C compiler.
       # This is currently not possible when compiling natively,
       # so we don't need to check hostPlatform != buildPlatform.
-      crossSystem = stdenv.hostPlatform // {
+      crossSystem = (cleanToolchain stdenv.hostPlatform) // {
         toolchain = "llvm";
         cc = "arocc";
         linker = "lld";
@@ -231,7 +234,7 @@ let
       # Bootstrap a cross stdenv using the Zig toolchain.
       # This is currently not possible when compiling natively,
       # so we don't need to check hostPlatform != buildPlatform.
-      crossSystem = stdenv.hostPlatform // {
+      crossSystem = (cleanToolchain stdenv.hostPlatform) // {
         toolchain = "llvm";
         cc = "zig";
         linker = "lld";