WIP: GCC with separated runtime libraries

pkgs/development/compilers/gcc-ng/11/custom-threading-model.patch

@@ -0,0 +1,126 @@
+diff --git a/config/gthr.m4 b/config/gthr.m4
+index 4b937306ad0..754e622f159 100644
+--- a/config/gthr.m4
++++ b/config/gthr.m4
+@@ -5,6 +5,35 @@ dnl Public License, this file may be distributed as part of a program
+ dnl that contains a configuration script generated by Autoconf, under
+ dnl the same distribution terms as the rest of that program.
+
++dnl Define thread model
++
++dnl usage: GCC_AC_THREAD_MODEL
++AC_DEFUN([GCC_AC_THREAD_MODEL],
++[
++# With threads
++# Pass with no value to take from compiler's metadata
++# Pass with a value to specify a thread package
++# 'single' means single threaded -- without threads.
++AC_ARG_WITH(threads,
++[AS_HELP_STRING([[--with-threads=MODEL]],
++		[specify thread model for this GCC
++		 runtime library])],,
++[with_threads=''])
++
++if test x"$with_threads" = x'yes'; then
++    AC_MSG_ERROR([Cannot pass bare --with-threads, must pass explicit --with-threads=MODEL])
++elif test x"$with_threads" = x'no'; then
++    target_thread_file=single
++elif test x"$with_threads" = x''; then
++    AC_MSG_CHECKING([for thread model used by GCC])
++    target_thread_file=`$CC -v 2>&1 | sed -n 's/^Thread model: //p'`
++    AC_MSG_RESULT([$target_thread_file])
++else
++    target_thread_file=$with_threads
++fi
++])
++
++
+ dnl Define header location by thread model
+
+ dnl usage: GCC_AC_THREAD_HEADER([thread_model])
+@@ -22,6 +51,9 @@ case $1 in
+     tpf)	thread_header=config/s390/gthr-tpf.h ;;
+     vxworks)	thread_header=config/gthr-vxworks.h ;;
+     win32)	thread_header=config/i386/gthr-win32.h ;;
++    *)
++        AC_MSG_ERROR([No known header for threading model '$1'.])
++        ;;
+ esac
+ AC_SUBST(thread_header)
+ ])
+diff --git a/libatomic/configure.ac b/libatomic/configure.ac
+index 2a371870c2f..42d2016b7a2 100644
+--- a/libatomic/configure.ac
++++ b/libatomic/configure.ac
+@@ -161,9 +161,7 @@ libtool_VERSION=3:0:2
+ AC_SUBST(libtool_VERSION)
+
+ # Check for used threading-model
+-AC_MSG_CHECKING([for thread model used by GCC])
+-target_thread_file=`$CC -v 2>&1 | sed -n 's/^Thread model: //p'`
+-AC_MSG_RESULT([$target_thread_file])
++GCC_AC_THREAD_MODEL
+
+ case "$target" in
+  *aarch64*)
+diff --git a/libgcc/configure.ac b/libgcc/configure.ac
+index 13a80b2551b..1209a0986e0 100644
+--- a/libgcc/configure.ac
++++ b/libgcc/configure.ac
+@@ -298,9 +298,7 @@ AC_SUBST([use_tm_clone_registry])
+
+ AC_LIB_PROG_LD_GNU
+
+-AC_MSG_CHECKING([for thread model used by GCC])
+-target_thread_file=`$CC -v 2>&1 | sed -n 's/^Thread model: //p'`
+-AC_MSG_RESULT([$target_thread_file]) 
++GCC_AC_THREAD_MODEL
+
+ # Check for assembler CFI support.
+ AC_CACHE_CHECK([whether assembler supports CFI directives], [libgcc_cv_cfi],
+diff --git a/libphobos/m4/druntime/os.m4 b/libphobos/m4/druntime/os.m4
+index 351558dbcda..2b44fbca8fc 100644
+--- a/libphobos/m4/druntime/os.m4
++++ b/libphobos/m4/druntime/os.m4
+@@ -32,7 +32,7 @@ case $1 in
+     # TODO: These targets need porting.
+     dce|mipssde|rtems|tpf|vxworks)
+ 	    DCFG_THREAD_MODEL="Single" ;;
+-    *)	    as_fn_error "Thread implementation '$1' not recognised" "$LINENO" 5 ;;
++    *)	    AC_MSG_ERROR([Thread implementation '$1' not recognised]) ;;
+ esac
+ AC_SUBST(DCFG_THREAD_MODEL)
+ ])
+diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
+index 1c0a4c13052..34a55d4e609 100644
+--- a/libstdc++-v3/acinclude.m4
++++ b/libstdc++-v3/acinclude.m4
+@@ -3977,9 +3977,7 @@ dnl Substs:
+ dnl  thread_header
+ dnl
+ AC_DEFUN([GLIBCXX_ENABLE_THREADS], [
+-  AC_MSG_CHECKING([for thread model used by GCC])
+-  target_thread_file=`$CXX -v 2>&1 | sed -n 's/^Thread model: //p'`
+-  AC_MSG_RESULT([$target_thread_file])
++  GCC_AC_THREAD_MODEL
+   GCC_AC_THREAD_HEADER([$target_thread_file])
+ ])
+
+@@ -3989,7 +3987,8 @@ dnl Check if gthread implementation defines the types and functions
+ dnl required by the c++0x thread library.  Conforming gthread
+ dnl implementations can define __GTHREADS_CXX0X to enable use with c++0x.
+ dnl
+-dnl GLIBCXX_ENABLE_SYMVERS must be done before this.
++dnl GLIBCXX_ENABLE_SYMVERS and GLIBCXX_ENABLE_THREADS must be done
++dnl before this.
+ dnl
+ AC_DEFUN([GLIBCXX_CHECK_GTHREADS], [
+   GLIBCXX_ENABLE(libstdcxx-threads,auto,,[enable C++11 threads support])
+@@ -4004,7 +4003,6 @@ AC_DEFUN([GLIBCXX_CHECK_GTHREADS], [
+   CXXFLAGS="$CXXFLAGS -fno-exceptions \
+ 	-I${toplevel_srcdir}/libgcc -I${toplevel_builddir}/libgcc"
+
+-  target_thread_file=`$CXX -v 2>&1 | sed -n 's/^Thread model: //p'`
+   case $target_thread_file in
+     posix)
+       CXXFLAGS="$CXXFLAGS -DSUPPORTS_WEAK -DGTHREAD_USE_WEAK -D_PTHREADS"

pkgs/development/compilers/gcc-ng/11/default.nix

@@ -0,0 +1,180 @@
+{ lowPrio, newScope, pkgs, lib, stdenv
+, fetchzip, wrapCCWith, overrideCC
+, preLibcCrossHeaders
+, buildGccTools # tools, but from the previous stage, for cross
+, targetGccLibraries # libraries, but from the next stage, for cross
+# This is the default binutils, but with *this* version of LLD rather
+# than the default LLVM verion's, if LLD is the choice. We use these for
+# the `useLLVM` bootstrapping below.
+, bintoolsNoLibc
+, bintools
+, darwin
+}:
+
+let
+  version = "11.2.0";
+
+  # fetchzip to unpack makes debug cycle much better
+  gcc_src = fetchzip {
+    url = "mirror://gcc/releases/gcc-${version}/gcc-${version}.tar.xz";
+    sha256 = "0aj1l0wkdbd5l2h5qybw0i5nwqbhqx89klnp7m5mwr63gmjfxwmi";
+  };
+
+  gcc_meta = {
+    description = "GNU Compiler Collection";
+    longDescription = ''
+      The GNU Compiler Collection includes compiler front ends for C, C++,
+      Objective-C, Fortran, OpenMP for C/C++/Fortran, and Ada, as well as
+      libraries for these languages (libstdc++, libgomp,...).
+
+      GCC development is a part of the GNU Project, aiming to improve the
+      compiler used in the GNU system including the GNU/Linux variant.
+    '';
+    homepage = "https://gcc.gnu.org/";
+    maintainers = with lib.maintainers; [ ericson231 sternenseemann ];
+  };
+  gcc_libs_meta = gcc_meta // {
+    license     = lib.licenses.lgpl3Plus;
+    platforms   = lib.platforms.all;
+  };
+  gcc_tools_meta = gcc_meta // {
+    license     = lib.licenses.gpl3Plus;
+    platforms   = lib.platforms.unix;
+  };
+
+  tools = lib.makeExtensible (tools: let
+    callPackage = newScope (tools // { inherit version gcc_tools_meta gcc_src buildGccTools; });
+
+  mkExtraBuildCommands0 = _: "";
+
+  mkExtraBuildCommands = _: "";
+
+  in {
+
+    gcc-unwrapped = callPackage ./gcc { };
+
+    # TODO: support libcxx? is there even an usecase for that?
+    gcc = if stdenv.cc.isClang then tools.libcxxGcc else tools.libstdcxxGcc;
+
+    libcxxGcc = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      extraPackages = [
+        targetGccLibraries.libgcc
+      ];
+      extraBuildCommands = mkExtraBuildCommands cc;
+    };
+
+    libstdcxxGcc = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      libcxx = targetGccLibraries.libstdcxx;
+      extraPackages = [
+        targetGccLibraries.libgcc
+      ];
+      extraBuildCommands = mkExtraBuildCommands cc;
+    };
+
+	# Below, is the GCC Next Gen bootstrapping logic. It handles building a
+	# fully GCC toolchain from scratch via Nix. No LLVM toolchain should be
+	# pulled in. We should deduplicate this bootstrapping with its LLVM
+	# equivalence one GCC "old gen" is gone.
+
+    gccUseGccNg = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      libcxx = targetGccLibraries.libstdcxx;
+      extraPackages = [
+        targetGccLibraries.libgcc
+      ] ++ lib.optionals (!stdenv.targetPlatform.isWasm) [
+        targetGccLibraries.libunwind
+      ];
+      extraBuildCommands = ''
+        echo "-B${targetGccLibraries.libgcc}/lib" >> $out/nix-support/cc-cflags
+      '' + lib.optionalString (!stdenv.targetPlatform.isWasm) ''
+        echo "--unwindlib=libunwind" >> $out/nix-support/cc-cflags
+      '' + lib.optionalString (!stdenv.targetPlatform.isWasm && stdenv.targetPlatform.useLLVM or false) ''
+        echo "-lunwind" >> $out/nix-support/cc-ldflags
+      '' + lib.optionalString stdenv.targetPlatform.isWasm ''
+        echo "-fno-exceptions" >> $out/nix-support/cc-cflags
+      '' + mkExtraBuildCommands cc;
+    };
+
+    gccNoLibstdcxx = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      libcxx = null;
+      extraPackages = [
+        targetGccLibraries.libgcc
+      ];
+      extraBuildCommands = ''
+        echo "-B${targetGccLibraries.libgcc}/lib" >> $out/nix-support/cc-cflags
+        echo "-B${targetGccLibraries.libatomic}/lib" >> $out/nix-support/cc-cflags
+      '' + mkExtraBuildCommands cc;
+    };
+
+    gccNoLibatomic = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      libcxx = null;
+      extraPackages = [
+        targetGccLibraries.libgcc
+      ];
+      extraBuildCommands = ''
+        echo "-B${targetGccLibraries.libgcc}/lib" >> $out/nix-support/cc-cflags
+      '' + mkExtraBuildCommands cc;
+    };
+
+    gccNoLibc = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      libcxx = null;
+      bintools = bintoolsNoLibc;
+      extraPackages = [
+        targetGccLibraries.libgcc
+      ];
+      extraBuildCommands = ''
+        echo "-B${targetGccLibraries.libgcc}/lib" >> $out/nix-support/cc-cflags
+      '' + mkExtraBuildCommands cc;
+    };
+
+    gccNoLibgcc = wrapCCWith rec {
+      cc = tools.gcc-unwrapped;
+      libcxx = null;
+      bintools = bintoolsNoLibc;
+      extraPackages = [ ];
+      extraBuildCommands = ''
+        echo "-nostartfiles" >> $out/nix-support/cc-cflags
+      '' + mkExtraBuildCommands0 cc;
+    };
+
+  });
+
+  libraries = lib.makeExtensible (libraries: let
+    callPackage = newScope (libraries // buildGccTools // { inherit version gcc_libs_meta gcc_src; });
+  in {
+
+    libgcc = callPackage ./libgcc {
+      stdenv = overrideCC stdenv buildGccTools.gccNoLibgcc;
+    };
+
+    stdenv = overrideCC stdenv buildGccTools.gcc;
+
+    libstdcxxStdenv = overrideCC stdenv buildGccTools.libstdcxxGcc;
+
+    libada = callPackage ./libada { };
+
+    libatomic = callPackage ./libatomic {
+      # TODO should libatomic be built before or after libc?
+      stdenv = overrideCC stdenv buildGccTools.gccNoLibatomic;
+    };
+
+    libssp = callPackage ./libssp {
+      # TODO should libssp be built before or after libc?
+      stdenv = overrideCC stdenv buildGccTools.gccNoLibatomic;
+    };
+
+    libgfortran = callPackage ./libgfortran { };
+
+    libstdcxx = callPackage ./libstdcxx {
+      stdenv = overrideCC stdenv buildGccTools.gccNoLibstdcxx;
+    };
+
+    # TODO add (gnu) libunwind here? can already be built separately aiui
+  });
+
+in { inherit tools libraries; } // libraries // tools