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-rw-r--r--nixpkgs/pkgs/development/compilers/gcc/7/default.nix400
-rw-r--r--nixpkgs/pkgs/development/compilers/gcc/7/riscv-no-relax.patch109
-rw-r--r--nixpkgs/pkgs/development/compilers/gcc/7/riscv-pthread-reentrant.patch13
3 files changed, 522 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/development/compilers/gcc/7/default.nix b/nixpkgs/pkgs/development/compilers/gcc/7/default.nix
new file mode 100644
index 000000000000..41af804e551f
--- /dev/null
+++ b/nixpkgs/pkgs/development/compilers/gcc/7/default.nix
@@ -0,0 +1,400 @@
+{ stdenv, targetPackages, fetchurl, fetchpatch, noSysDirs
+, langC ? true, langCC ? true, langFortran ? false
+, langObjC ? stdenv.targetPlatform.isDarwin
+, langObjCpp ? stdenv.targetPlatform.isDarwin
+, langGo ? false
+, profiledCompiler ? false
+, staticCompiler ? false
+, enableShared ? true
+, texinfo ? null
+, perl ? null # optional, for texi2pod (then pod2man)
+, gmp, mpfr, libmpc, gettext, which
+, libelf                      # optional, for link-time optimizations (LTO)
+, isl ? null # optional, for the Graphite optimization framework.
+, zlib ? null
+, enableMultilib ? false
+, enablePlugin ? stdenv.hostPlatform == stdenv.buildPlatform # Whether to support user-supplied plug-ins
+, name ? "gcc"
+, libcCross ? null
+, crossStageStatic ? false
+, # Strip kills static libs of other archs (hence no cross)
+  stripped ? stdenv.hostPlatform == stdenv.buildPlatform
+          && stdenv.targetPlatform == stdenv.hostPlatform
+, gnused ? null
+, cloog # unused; just for compat with gcc4, as we override the parameter on some places
+, buildPackages
+}:
+
+# LTO needs libelf and zlib.
+assert libelf != null -> zlib != null;
+
+# Make sure we get GNU sed.
+assert stdenv.hostPlatform.isDarwin -> gnused != null;
+
+# The go frontend is written in c++
+assert langGo -> langCC;
+
+with stdenv.lib;
+with builtins;
+
+let version = "7.4.0";
+
+    inherit (stdenv) buildPlatform hostPlatform targetPlatform;
+
+    patches =
+      [ # https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00633.html
+        ./riscv-pthread-reentrant.patch
+        # https://gcc.gnu.org/ml/gcc-patches/2018-03/msg00297.html
+        ./riscv-no-relax.patch
+      ]
+      ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
+      ++ optional noSysDirs ../no-sys-dirs.patch
+      ++ optional (hostPlatform != buildPlatform) (fetchpatch { # XXX: Refine when this should be applied
+        url = "https://git.busybox.net/buildroot/plain/package/gcc/7.1.0/0900-remove-selftests.patch?id=11271540bfe6adafbc133caf6b5b902a816f5f02";
+        sha256 = "0mrvxsdwip2p3l17dscpc1x8vhdsciqw1z5q9i6p5g9yg1cqnmgs";
+      })
+      ++ optional langFortran ../gfortran-driving.patch
+      ++ optional (targetPlatform.libc == "musl" && targetPlatform.isPower) ../ppc-musl.patch
+      ++ optional (targetPlatform.libc == "musl") ../libgomp-dont-force-initial-exec.patch;
+
+    /* Cross-gcc settings (build == host != target) */
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
+    crossConfigureFlags =
+      # Ensure that -print-prog-name is able to find the correct programs.
+      [ "--with-as=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
+        "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld" ] ++
+      (if crossMingw && crossStageStatic then [
+        "--with-headers=${getDev libcCross}${libcCross.incdir or "/include"}"
+        "--with-gcc"
+        "--with-gnu-as"
+        "--with-gnu-ld"
+        "--with-gnu-ld"
+        "--disable-shared"
+        "--disable-nls"
+        "--disable-debug"
+        "--enable-sjlj-exceptions"
+        "--enable-threads=win32"
+        "--disable-win32-registry"
+        "--disable-libmpx" # requires libc
+      ] else if crossStageStatic then [
+        "--disable-libssp"
+        "--disable-nls"
+        "--without-headers"
+        "--disable-threads"
+        "--disable-libgomp"
+        "--disable-libquadmath"
+        "--disable-shared"
+        "--disable-libatomic" # requires libc
+        "--disable-decimal-float" # requires libc
+        "--disable-libmpx" # requires libc
+      ] else [
+        (if crossDarwin then "--with-sysroot=${getLib libcCross}/share/sysroot"
+         else                "--with-headers=${getDev libcCross}${libcCross.incdir or "/include"}")
+        "--enable-__cxa_atexit"
+        "--enable-long-long"
+      ] ++
+        (if crossMingw then [
+          "--enable-threads=win32"
+          "--enable-sjlj-exceptions"
+          "--enable-hash-synchronization"
+          "--enable-libssp"
+          "--disable-nls"
+          "--with-dwarf2"
+          # To keep ABI compatibility with upstream mingw-w64
+          "--enable-fully-dynamic-string"
+        ] else
+          optionals (targetPlatform.libc == "uclibc" || targetPlatform.libc == "musl") [
+            # libsanitizer requires netrom/netrom.h which is not
+            # available in uclibc.
+            "--disable-libsanitizer"
+            # In uclibc cases, libgomp needs an additional '-ldl'
+            # and as I don't know how to pass it, I disable libgomp.
+            "--disable-libgomp"
+            # musl at least, disable: https://git.buildroot.net/buildroot/commit/?id=873d4019f7fb00f6a80592224236b3ba7d657865
+            "--disable-libmpx"
+          ]
+          ++ optional (targetPlatform.libc == "newlib") "--with-newlib"
+          ++ optional (targetPlatform.libc == "avrlibc") "--with-avrlibc"
+          ++ [
+            "--enable-threads=${if targetPlatform.isUnix then "posix"
+                                else if targetPlatform.isWindows then "win32"
+                                else "single"}"
+            "--enable-nls"
+            # No final libdecnumber (it may work only in 386)
+            "--disable-decimal-float"
+          ]));
+    stageNameAddon = if crossStageStatic then "-stage-static" else "-stage-final";
+    crossNameAddon = if targetPlatform != hostPlatform then "${targetPlatform.config}${stageNameAddon}-" else "";
+
+    bootstrap = targetPlatform == hostPlatform;
+
+in
+
+stdenv.mkDerivation ({
+  name = crossNameAddon + "${name}${if stripped then "" else "-debug"}-${version}";
+
+  builder = ../builder.sh;
+
+  src = fetchurl {
+    url = "mirror://gcc/releases/gcc-${version}/gcc-${version}.tar.xz";
+    sha256 = "0lgy170b0pp60j9cczqkmaqyjjb584vfamj4c30swd7k0j6y5pgd";
+  };
+
+  inherit patches;
+
+  outputs = [ "out" "lib" "man" "info" ];
+  setOutputFlags = false;
+  NIX_NO_SELF_RPATH = true;
+
+  libc_dev = stdenv.cc.libc_dev;
+
+  hardeningDisable = [ "format" "pie" ];
+
+  # This should kill all the stdinc frameworks that gcc and friends like to
+  # insert into default search paths.
+  prePatch = stdenv.lib.optionalString hostPlatform.isDarwin ''
+    substituteInPlace gcc/config/darwin-c.c \
+      --replace 'if (stdinc)' 'if (0)'
+
+    substituteInPlace libgcc/config/t-slibgcc-darwin \
+      --replace "-install_name @shlib_slibdir@/\$(SHLIB_INSTALL_NAME)" "-install_name $lib/lib/\$(SHLIB_INSTALL_NAME)"
+
+    substituteInPlace libgfortran/configure \
+      --replace "-install_name \\\$rpath/\\\$soname" "-install_name $lib/lib/\\\$soname"
+  '';
+
+  postPatch = ''
+    configureScripts=$(find . -name configure)
+    for configureScript in $configureScripts; do
+      patchShebangs $configureScript
+    done
+  '' + (
+    if targetPlatform != hostPlatform || stdenv.cc.libc != null then
+      # On NixOS, use the right path to the dynamic linker instead of
+      # `/lib/ld*.so'.
+      let
+        libc = if libcCross != null then libcCross else stdenv.cc.libc;
+      in
+        (
+        '' echo "fixing the \`GLIBC_DYNAMIC_LINKER', \`UCLIBC_DYNAMIC_LINKER', and \`MUSL_DYNAMIC_LINKER' macros..."
+           for header in "gcc/config/"*-gnu.h "gcc/config/"*"/"*.h
+           do
+             grep -q _DYNAMIC_LINKER "$header" || continue
+             echo "  fixing \`$header'..."
+             sed -i "$header" \
+                 -e 's|define[[:blank:]]*\([UCG]\+\)LIBC_DYNAMIC_LINKER\([0-9]*\)[[:blank:]]"\([^\"]\+\)"$|define \1LIBC_DYNAMIC_LINKER\2 "${libc.out}\3"|g' \
+                 -e 's|define[[:blank:]]*MUSL_DYNAMIC_LINKER\([0-9]*\)[[:blank:]]"\([^\"]\+\)"$|define MUSL_DYNAMIC_LINKER\1 "${libc.out}\2"|g'
+           done
+        ''
+        + stdenv.lib.optionalString (targetPlatform.libc == "musl")
+        ''
+            sed -i gcc/config/linux.h -e '1i#undef LOCAL_INCLUDE_DIR'
+        ''
+        )
+    else "")
+      + stdenv.lib.optionalString targetPlatform.isAvr ''
+        makeFlagsArray+=(
+           'LIMITS_H_TEST=false'
+        )
+      '';
+
+  inherit noSysDirs staticCompiler crossStageStatic
+    libcCross crossMingw;
+
+  depsBuildBuild = [ buildPackages.stdenv.cc ];
+  nativeBuildInputs = [ texinfo which gettext ]
+    ++ (optional (perl != null) perl);
+
+  # For building runtime libs
+  depsBuildTarget =
+    if hostPlatform == buildPlatform then [
+      targetPackages.stdenv.cc.bintools # newly-built gcc will be used
+    ] else assert targetPlatform == hostPlatform; [ # build != host == target
+      stdenv.cc
+    ];
+
+  buildInputs = [
+    gmp mpfr libmpc libelf
+    targetPackages.stdenv.cc.bintools # For linking code at run-time
+  ] ++ (optional (isl != null) isl)
+    ++ (optional (zlib != null) zlib)
+    # The builder relies on GNU sed (for instance, Darwin's `sed' fails with
+    # "-i may not be used with stdin"), and `stdenvNative' doesn't provide it.
+    ++ (optional hostPlatform.isDarwin gnused)
+    ;
+
+  NIX_CFLAGS_COMPILE = stdenv.lib.optionalString (stdenv.cc.isClang && langFortran) "-Wno-unused-command-line-argument";
+  NIX_LDFLAGS = stdenv.lib.optionalString  hostPlatform.isSunOS "-lm -ldl";
+
+  preConfigure = stdenv.lib.optionalString (hostPlatform.isSunOS && hostPlatform.is64bit) ''
+    export NIX_LDFLAGS=`echo $NIX_LDFLAGS | sed -e s~$prefix/lib~$prefix/lib/amd64~g`
+    export LDFLAGS_FOR_TARGET="-Wl,-rpath,$prefix/lib/amd64 $LDFLAGS_FOR_TARGET"
+    export CXXFLAGS_FOR_TARGET="-Wl,-rpath,$prefix/lib/amd64 $CXXFLAGS_FOR_TARGET"
+    export CFLAGS_FOR_TARGET="-Wl,-rpath,$prefix/lib/amd64 $CFLAGS_FOR_TARGET"
+  '';
+
+  dontDisableStatic = true;
+
+  # TODO(@Ericson2314): Always pass "--target" and always prefix.
+  configurePlatforms = [ "build" "host" ] ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
+
+  configureFlags =
+    # Basic dependencies
+    [
+      "--with-gmp-include=${gmp.dev}/include"
+      "--with-gmp-lib=${gmp.out}/lib"
+      "--with-mpfr-include=${mpfr.dev}/include"
+      "--with-mpfr-lib=${mpfr.out}/lib"
+      "--with-mpc=${libmpc}"
+    ] ++
+    optional (libelf != null) "--with-libelf=${libelf}" ++
+    optional (!(crossMingw && crossStageStatic))
+      "--with-native-system-header-dir=${getDev stdenv.cc.libc}/include" ++
+
+    # Basic configuration
+    [
+      "--enable-lto"
+      "--disable-libstdcxx-pch"
+      "--without-included-gettext"
+      "--with-system-zlib"
+      "--enable-static"
+      "--enable-languages=${
+        concatStrings (intersperse ","
+          (  optional langC        "c"
+          ++ optional langCC       "c++"
+          ++ optional langFortran  "fortran"
+          ++ optional langGo       "go"
+          ++ optional langObjC     "objc"
+          ++ optional langObjCpp   "obj-c++"
+          ++ optionals crossDarwin [ "objc" "obj-c++" ]
+          )
+        )
+      }"
+    ] ++
+
+    (if (enableMultilib || targetPlatform.isAvr)
+      then ["--enable-multilib" "--disable-libquadmath"]
+      else ["--disable-multilib"]) ++
+    optional (!enableShared) "--disable-shared" ++
+    (if enablePlugin
+      then ["--enable-plugin"]
+      else ["--disable-plugin"]) ++
+
+    # Optional features
+    optional (isl != null) "--with-isl=${isl}" ++
+
+    (import ../common/platform-flags.nix { inherit (stdenv) lib targetPlatform; }) ++
+    optional (targetPlatform != hostPlatform) crossConfigureFlags ++
+    optional (!bootstrap) "--disable-bootstrap" ++
+
+    # Platform-specific flags
+    optional (targetPlatform == hostPlatform && targetPlatform.isi686) "--with-arch=i686" ++
+    optionals hostPlatform.isSunOS [
+      "--enable-long-long" "--enable-libssp" "--enable-threads=posix" "--disable-nls" "--enable-__cxa_atexit"
+      # On Illumos/Solaris GNU as is preferred
+      "--with-gnu-as" "--without-gnu-ld"
+    ]
+    ++ optionals (targetPlatform == hostPlatform && targetPlatform.libc == "musl") [
+      "--disable-libsanitizer"
+      "--disable-symvers"
+      "libat_cv_have_ifunc=no"
+      "--disable-gnu-indirect-function"
+    ]
+    ++ optional (targetPlatform.isAarch64) "--enable-fix-cortex-a53-843419"
+  ;
+
+  targetConfig = if targetPlatform != hostPlatform then targetPlatform.config else null;
+
+  buildFlags = optional
+    (bootstrap && hostPlatform == buildPlatform)
+    (if profiledCompiler then "profiledbootstrap" else "bootstrap");
+
+  dontStrip = !stripped;
+
+  doCheck = false; # requires a lot of tools, causes a dependency cycle for stdenv
+
+  installTargets =
+    if stripped
+    then "install-strip"
+    else "install";
+
+  # https://gcc.gnu.org/install/specific.html#x86-64-x-solaris210
+  ${if hostPlatform.system == "x86_64-solaris" then "CC" else null} = "gcc -m64";
+
+  # Setting $CPATH and $LIBRARY_PATH to make sure both `gcc' and `xgcc' find the
+  # library headers and binaries, regarless of the language being compiled.
+  #
+  # Likewise, the LTO code doesn't find zlib.
+  #
+  # Cross-compiling, we need gcc not to read ./specs in order to build the g++
+  # compiler (after the specs for the cross-gcc are created). Having
+  # LIBRARY_PATH= makes gcc read the specs from ., and the build breaks.
+
+  CPATH = optionals (targetPlatform == hostPlatform) (makeSearchPathOutput "dev" "include" ([]
+    ++ optional (zlib != null) zlib
+  ));
+
+  LIBRARY_PATH = optionals (targetPlatform == hostPlatform) (makeLibraryPath (optional (zlib != null) zlib));
+
+  EXTRA_TARGET_FLAGS = optionals
+    (targetPlatform != hostPlatform && libcCross != null)
+    ([
+      "-idirafter ${getDev libcCross}${libcCross.incdir or "/include"}"
+    ] ++ optionals (! crossStageStatic) [
+      "-B${libcCross.out}${libcCross.libdir or "/lib"}"
+    ]);
+
+  EXTRA_TARGET_LDFLAGS = optionals
+    (targetPlatform != hostPlatform && libcCross != null)
+    ([
+      "-Wl,-L${libcCross.out}${libcCross.libdir or "/lib"}"
+    ] ++ (if crossStageStatic then [
+        "-B${libcCross.out}${libcCross.libdir or "/lib"}"
+      ] else [
+        "-Wl,-rpath,${libcCross.out}${libcCross.libdir or "/lib"}"
+        "-Wl,-rpath-link,${libcCross.out}${libcCross.libdir or "/lib"}"
+    ]));
+
+  passthru = {
+    inherit langC langCC langObjC langObjCpp langFortran langGo version;
+    isGNU = true;
+  };
+
+  enableParallelBuilding = true;
+  inherit enableMultilib;
+
+  inherit (stdenv) is64bit;
+
+  meta = {
+    homepage = https://gcc.gnu.org/;
+    license = stdenv.lib.licenses.gpl3Plus;  # runtime support libraries are typically LGPLv3+
+    description = "GNU Compiler Collection, version ${version}"
+      + (if stripped then "" else " (with debugging info)");
+
+    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.
+    '';
+
+    maintainers = with stdenv.lib.maintainers; [ ];
+
+    platforms =
+      stdenv.lib.platforms.linux ++
+      stdenv.lib.platforms.freebsd ++
+      stdenv.lib.platforms.illumos ++
+      stdenv.lib.platforms.darwin;
+  };
+}
+
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+  makeFlags = [ "all-gcc" "all-target-libgcc" ];
+  installTargets = "install-gcc install-target-libgcc";
+}
+
+// optionalAttrs (enableMultilib) { dontMoveLib64 = true; }
+)
diff --git a/nixpkgs/pkgs/development/compilers/gcc/7/riscv-no-relax.patch b/nixpkgs/pkgs/development/compilers/gcc/7/riscv-no-relax.patch
new file mode 100644
index 000000000000..93d9cd1d60f5
--- /dev/null
+++ b/nixpkgs/pkgs/development/compilers/gcc/7/riscv-no-relax.patch
@@ -0,0 +1,109 @@
+commit e7c570f37384d824cb9725f237920e9691e57269
+gpg: Signature made Tue 06 Mar 2018 04:52:46 PM PST
+gpg:                using RSA key 00CE76D1834960DFCE886DF8EF4CA1502CCBAB41
+gpg:                issuer "palmer@dabbelt.com"
+gpg: Good signature from "Palmer Dabbelt <palmer@dabbelt.com>" [ultimate]
+gpg:                 aka "Palmer Dabbelt <palmer@sifive.com>" [ultimate]
+Author: Palmer Dabbelt <palmer@sifive.com>
+Date:   Thu Mar 1 12:01:06 2018 -0800
+
+    RISC-V: Add and document the "-mno-relax" option
+
+    RISC-V relies on aggressive linker relaxation to get good code size.  As
+    a result no text symbol addresses can be known until link time, which
+    means that alignment must be handled during the link.  This alignment
+    pass is essentially just another linker relaxation, so this has the
+    unfortunate side effect that linker relaxation is required for
+    correctness on many RISC-V targets.
+
+    The RISC-V assembler has supported an ".option norelax" for a long time
+    because there are situations in which linker relaxation is a bad idea --
+    the canonical example is when trying to materialize the initial value of
+    the global pointer into a register, which would otherwise be relaxed to
+    a NOP.  We've been relying on users who want to disable relaxation for
+    an entire link to pass "-Wl,--no-relax", but that still relies on the
+    linker relaxing R_RISCV_ALIGN to handle alignment despite it not being
+    strictly necessary.
+
+    This patch adds a GCC option, "-mno-relax", that disable linker
+    relaxation by adding ".option norelax" to the top of every generated
+    assembly file.  The assembler is smart enough to handle alignment at
+    assemble time for files that have never emitted a relaxable relocation,
+    so this is sufficient to really disable all relaxations in the linker,
+    which results in significantly faster link times for large objects.
+
+    This also has the side effect of allowing toolchains that don't support
+    linker relaxation (LLVM and the Linux module loader) to function
+    correctly.  Toolchains that don't support linker relaxation should
+    default to "-mno-relax" and error when presented with any R_RISCV_ALIGN
+    relocation as those need to be handled for correctness.
+
+    gcc/ChangeLog
+
+    2018-03-01  Palmer Dabbelt  <palmer@sifive.com>
+
+            * config/riscv/riscv.opt (mrelax): New option.
+            * config/riscv/riscv.c (riscv_file_start): Emit ".option
+            "norelax" when riscv_mrelax is disabled.
+            * doc/invoke.texi (RISC-V): Document "-mrelax" and "-mno-relax".
+
+diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
+index c38f6c394d54..3e81874de232 100644
+--- a/gcc/config/riscv/riscv.c
++++ b/gcc/config/riscv/riscv.c
+@@ -3979,6 +3979,11 @@ riscv_file_start (void)
+
+   /* Instruct GAS to generate position-[in]dependent code.  */
+   fprintf (asm_out_file, "\t.option %spic\n", (flag_pic ? "" : "no"));
++
++  /* If the user specifies "-mno-relax" on the command line then disable linker
++     relaxation in the assembler.  */
++  if (! riscv_mrelax)
++    fprintf (asm_out_file, "\t.option norelax\n");
+ }
+
+ /* Implement TARGET_ASM_OUTPUT_MI_THUNK.  Generate rtl rather than asm text
+diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt
+index 581a26bb5c1e..b37ac75d9bb4 100644
+--- a/gcc/config/riscv/riscv.opt
++++ b/gcc/config/riscv/riscv.opt
+@@ -106,6 +106,11 @@ mexplicit-relocs
+ Target Report Mask(EXPLICIT_RELOCS)
+ Use %reloc() operators, rather than assembly macros, to load addresses.
+
++mrelax
++Target Bool Var(riscv_mrelax) Init(1)
++Take advantage of linker relaxations to reduce the number of instructions
++required to materialize symbol addresses.
++
+ Mask(64BIT)
+
+ Mask(MUL)
+diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
+index 8d366c626bae..deb48af2ecad 100644
+--- a/gcc/doc/invoke.texi
++++ b/gcc/doc/invoke.texi
+@@ -1042,7 +1042,8 @@ See RS/6000 and PowerPC Options.
+ -msave-restore  -mno-save-restore @gol
+ -mstrict-align -mno-strict-align @gol
+ -mcmodel=medlow -mcmodel=medany @gol
+--mexplicit-relocs  -mno-explicit-relocs @gol}
++-mexplicit-relocs  -mno-explicit-relocs @gol
++-mrelax -mno-relax @gol}
+
+ @emph{RL78 Options}
+ @gccoptlist{-msim  -mmul=none  -mmul=g13  -mmul=g14  -mallregs @gol
+@@ -23102,6 +23103,12 @@ Use or do not use assembler relocation operators when dealing with symbolic
+ addresses.  The alternative is to use assembler macros instead, which may
+ limit optimization.
+
++@item -mrelax
++@itemx -mno-relax
++Take advantage of linker relaxations to reduce the number of instructions
++required to materialize symbol addresses. The default is to take advantage of
++linker relaxations.
++
+ @end table
+
+ @node RL78 Options
+
diff --git a/nixpkgs/pkgs/development/compilers/gcc/7/riscv-pthread-reentrant.patch b/nixpkgs/pkgs/development/compilers/gcc/7/riscv-pthread-reentrant.patch
new file mode 100644
index 000000000000..c7527ffb2b16
--- /dev/null
+++ b/nixpkgs/pkgs/development/compilers/gcc/7/riscv-pthread-reentrant.patch
@@ -0,0 +1,13 @@
+Index: gcc/config/riscv/linux.h
+===================================================================
+--- a/gcc/config/riscv/linux.h	(revision 257620)
++++ b/gcc/config/riscv/linux.h	(revision 257621)
+@@ -47,6 +47,8 @@
+ 
+ #define ICACHE_FLUSH_FUNC "__riscv_flush_icache"
+ 
++#define CPP_SPEC "%{pthread:-D_REENTRANT}"
++
+ #define LINK_SPEC "\
+ -melf" XLEN_SPEC "lriscv \
+ %{shared} \