RFC: Add gcc offloading to GPUs

lib/systems/examples.nix

@@ -167,6 +167,11 @@ rec {
     config = "avr";
   };
 
+  amdgcn = {
+    config = "amdgcn-amdhsa";
+    libc = "newlib";
+  };
+
   vc4 = {
     config = "vc4-elf";
     libc = "newlib";

lib/systems/parse.nix

@@ -163,6 +163,8 @@ rec {
     msp430   = { bits = 16; significantByte = littleEndian; family = "msp430"; };
     avr      = { bits = 8; family = "avr"; };
 
+    amdgcn   = { bits = 64; significantByte = littleEndian; family = "amdgcn"; };
+
     vc4      = { bits = 32; significantByte = littleEndian; family = "vc4"; };
 
     or1k     = { bits = 32; significantByte = bigEndian; family = "or1k"; };
@@ -338,6 +340,7 @@ rec {
     ghcjs    = { execFormat = unknown; families = { }; };
     genode   = { execFormat = elf;     families = { }; };
     mmixware = { execFormat = unknown; families = { }; };
+    amdhsa   = { execFormat = unknown; families = { }; };
   } // { # aliases
     # 'darwin' is the kernel for all of them. We choose macOS by default.
     darwin = kernels.macos;

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

@@ -21,6 +21,7 @@
 , gnugrep ? null
 , expand-response-params
 , libcxx ? null
+, extraCompilerB ? []
 
 # Whether or not to add `-B` and `-L` to `nix-support/cc-{c,ld}flags`
 , useCcForLibs ?
@@ -614,7 +615,12 @@ stdenvNoCC.mkDerivation {
       ccLDFlags+=" -L${cc_solib}/lib"
       ccCFlags+=" -B${cc_solib}/lib"
 
-    '' + optionalString (cc.langAda or false && !isArocc) ''
+    '' + (concatMapStrings (p: ''
+        ccCFlags+=" -B${p}/libexec/gcc/${stdenvNoCC.buildPlatform.config}/${p.version}"
+        ccCFlags+=" -B${p}/bin"
+        ccCFlags+=" -foffload-options=-Wl,-L${p}/${p.stdenv.targetPlatform.config}/lib"
+      '') extraCompilerB)
+    + optionalString (cc.langAda or false && !isArocc) ''
       touch "$out/nix-support/gnat-cflags"
       touch "$out/nix-support/gnat-ldflags"
       basePath=$(echo $cc/lib/*/*/*)

pkgs/development/compilers/gcc/common/builder.nix

@@ -3,6 +3,7 @@
   stdenv,
   enableMultilib,
   targetConfig,
+  version,
 }:
 
 let
@@ -169,6 +170,10 @@ originalAttrs:
       fi
 
       eval "$oldOpts"
+    '' +  lib.optionalString (targetConfig == "amdgcn-amdhsa") ''
+      makeFlagsArray=''${makeFlagsArray[@]/CFLAGS_FOR_TARGET=*}
+      makeFlagsArray=''${makeFlagsArray[@]/CXXFLAGS_FOR_TARGET=*}
+      makeFlagsArray=''${makeFlagsArray[@]/FLAGS_FOR_TARGET=*}
     '';
 
     preConfigure =
@@ -219,7 +224,7 @@ originalAttrs:
         # symlink), this ensures that in every case we can assume that
         # $lib/lib contains the .so files
         lib.optionalString (with stdenv; targetPlatform.config != hostPlatform.config) ''
-          ln -Ts "''${!outputLib}/''${targetConfig}/lib" $lib/lib
+          ln -Ts "''${!outputLib}/''${targetConfig}/lib" "''${!outputLib}/lib"
         ''
       +
         # Make `lib64` symlinks to `lib`.
@@ -312,6 +317,11 @@ originalAttrs:
               ln -sf "$man_prefix"gcc.1 "$i"
           fi
       done
+    '' + lib.optionalString (targetConfig == "amdgcn-amdhsa") ''
+      for a in ld as ar nm runlib; do
+        ln -s $(type -P amdgcn-amdhsa-$a) \
+           $out/lib/gcc/x86_64-unknown-linux-gnu/${version}/accel/amdgcn-amdhsa/$a
+      done
     '';
   }
 ))

pkgs/development/compilers/gcc/common/configure-flags.nix

@@ -9,6 +9,7 @@
 
 , enableLTO
 , enableMultilib
+, enableOffload
 , enablePlugin
 , disableGdbPlugin ? !enablePlugin
 , enableShared
@@ -53,10 +54,10 @@ let
 
   crossConfigureFlags =
     # Ensure that -print-prog-name is able to find the correct programs.
-    [
+    (lib.optionals (targetPlatform.config != "amdgcn-amdhsa") [
       "--with-as=${if targetPackages.stdenv.cc.bintools.isLLVM then binutils else targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-as"
       "--with-ld=${targetPackages.stdenv.cc.bintools}/bin/${targetPlatform.config}-ld"
-    ]
+    ])
     ++ (if withoutTargetLibc then [
       "--disable-libssp"
       "--disable-nls"
@@ -84,9 +85,11 @@ let
       # See Note [Windows Exception Handling]
       "--enable-sjlj-exceptions"
       "--with-dwarf2"
-    ] else [
-      (if crossDarwin then "--with-sysroot=${lib.getLib libcCross}/share/sysroot"
-       else                "--with-headers=${lib.getDev libcCross}${libcCross.incdir or "/include"}")
+    ] else (
+      lib.optional crossDarwin "--with-sysroot=${lib.getLib libcCross}/share/sysroot"
+      ++ lib.optional (!crossDarwin && targetPlatform.config != "amdgcn-amdhsa")
+        "--with-sysroot=${lib.getLib libcCross}/share/sysroot"
+      ++ [
       "--enable-__cxa_atexit"
       "--enable-long-long"
       "--enable-threads=${if targetPlatform.isUnix then "posix"
@@ -97,9 +100,10 @@ let
       # libsanitizer requires netrom/netrom.h which is not
       # available in uclibc.
       "--disable-libsanitizer"
-    ] ++ lib.optional (targetPlatform.libc == "newlib" || targetPlatform.libc == "newlib-nano") "--with-newlib"
+    ] ++ lib.optional ((targetPlatform.libc == "newlib" || targetPlatform.libc == "newlib-nano") &&
+            targetPlatform.config != "amdgcn-amdhsa") "--with-newlib"
       ++ lib.optional (targetPlatform.libc == "avrlibc") "--with-avrlibc"
-    );
+    ));
 
   configureFlags =
     # Basic dependencies
@@ -110,7 +114,7 @@ let
       "--with-mpfr-lib=${mpfr.out}/lib"
       "--with-mpc=${libmpc}"
     ]
-    ++ lib.optionals (!withoutTargetLibc) [
+    ++ lib.optionals (!withoutTargetLibc && targetPlatform.config != "amdgcn-amdhsa") [
       (if libcCross == null
        then (
         # GCC will search for the headers relative to SDKROOT on Darwin, so it will find them in the store.
@@ -160,7 +164,12 @@ let
       "--disable-libstdcxx-pch"
       "--without-included-gettext"
       "--with-system-zlib"
+    ] ++ lib.optionals (targetPlatform.config != "amdgcn-amdhsa") [
       "--enable-static"
+    ] ++ lib.optionals (targetPlatform.config == "amdgcn-amdhsa") [
+      "--disable-sjlj-exceptions"
+      "--disable-libquadmath"
+    ] ++ [
       "--enable-languages=${
         lib.concatStringsSep ","
           (  lib.optional langC        "c"
@@ -177,7 +186,7 @@ let
           )
       }"
     ]
-
+    ++ lib.optional enableOffload "--enable-offload-targets=amdgcn-amdhsa"
     ++ (if (enableMultilib || targetPlatform.isAvr)
       then ["--enable-multilib" "--disable-libquadmath"]
       else ["--disable-multilib"])
@@ -208,7 +217,9 @@ let
     ++ import ../common/platform-flags.nix { inherit (stdenv)  targetPlatform; inherit lib; }
     ++ lib.optionals (targetPlatform != hostPlatform) crossConfigureFlags
     ++ lib.optional disableBootstrap' "--disable-bootstrap"
-
+    ++ lib.optionals (targetPlatform.config == "amdgcn-amdhsa") [
+      "--target=amdgcn-amdhsa" "--enable-as-accelerator-for=x86_64-unknown-linux-gnu"
+    ]
     # Platform-specific flags
     ++ lib.optional (targetPlatform == hostPlatform && targetPlatform.isx86_32) "--with-arch=${stdenv.hostPlatform.parsed.cpu.name}"
     ++ lib.optional targetPlatform.isNetBSD "--disable-libssp" # Provided by libc.

pkgs/development/compilers/gcc/common/dependencies.nix

@@ -31,11 +31,26 @@
 let
   inherit (lib) optionals;
   inherit (stdenv) buildPlatform hostPlatform targetPlatform;
+
+  ## llvm18 fails with gcc <14
+  # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114419
+  llvmAmd =
+    let
+      llvm = buildPackages.llvmPackages_19;
+    in buildPackages.runCommand "${llvm.llvm.name}-wrapper" {} ''
+      mkdir -p $out/bin
+      for a in ar nm ranlib; do
+        ln -s ${llvm.llvm}/bin/llvm-$a $out/bin/amdgcn-amdhsa-$a
+      done
+      ln -s ${llvm.llvm}/bin/llvm-mc $out/bin/amdgcn-amdhsa-as
+      ln -s ${llvm.lld}/bin/lld $out/bin/amdgcn-amdhsa-ld
+    '';
 in
 
 {
   # same for all gcc's
-  depsBuildBuild = [ buildPackages.stdenv.cc ];
+  depsBuildBuild = [ buildPackages.stdenv.cc ] ++
+      lib.optional (targetPlatform.config == "amdgcn-amdhsa") llvmAmd;
 
   nativeBuildInputs =
     [
@@ -55,7 +70,9 @@ in
   # same for all gcc's
   depsBuildTarget =
     (
-      if hostPlatform == buildPlatform then
+      if (targetPlatform.config == "amdgcn-amdhsa") then
+        [ ]
+      else if hostPlatform == buildPlatform then
         [
           targetPackages.stdenv.cc.bintools # newly-built gcc will be used
         ]
@@ -75,7 +92,7 @@ in
       libmpc
     ]
     ++ optionals (lib.versionAtLeast version "10") [ libxcrypt ]
-    ++ [
+    ++ optionals (targetPlatform.config != "amdgcn-amdhsa") [
       targetPackages.stdenv.cc.bintools # For linking code at run-time
     ]
     ++ optionals (isl != null) [ isl ]

pkgs/development/compilers/gcc/common/extra-target-flags.nix

@@ -23,7 +23,7 @@ in
           [
             "-O2 -idirafter ${lib.getDev dep}${dep.incdir or "/include"}"
           ]
-          ++ lib.optionals (!withoutTargetLibc) [
+          ++ lib.optionals (!withoutTargetLibc && targetPlatform.config != "amdgcn-amdhsa") [
             "-B${lib.getLib dep}${dep.libdir or "/lib"}"
           ]
         );

pkgs/development/compilers/gcc/common/strip-attributes.nix

@@ -57,7 +57,7 @@
         )
         popd
     ''
-    + lib.optionalString (!langJit) ''
+    + lib.optionalString (!langJit && stdenv.targetPlatform.config != "amdgcn-amdhsa") ''
       ${
         # keep indentation
         ""

pkgs/development/compilers/gcc/default.nix

@@ -13,9 +13,10 @@
 , staticCompiler ? false
 , enableShared ? stdenv.targetPlatform.hasSharedLibraries
 , enableLTO ? stdenv.hostPlatform.hasSharedLibraries
+, enableOffload ? false
 , texinfo ? null
 , perl ? null # optional, for texi2pod (then pod2man)
-, gmp, mpfr, libmpc, gettext, which, patchelf, binutils
+, gmp, mpfr, libmpc, gettext, which, patchelf, binutils, newlib
 , isl ? null # optional, for the Graphite optimization framework.
 , zlib ? null
 , libucontext ? null
@@ -111,6 +112,7 @@ let
         disableBootstrap
         disableGdbPlugin
         enableLTO
+        enableOffload
         enableMultilib
         enablePlugin
         enableShared
@@ -152,6 +154,7 @@ let
         threadsCross
         which
         zlib
+        newlib
       ;
     };
 
@@ -187,7 +190,7 @@ pipe ((callFile ./common/builder.nix {}) ({
 
   inherit patches;
 
-  outputs = [ "out" "man" "info" ] ++ optional (!langJit) "lib";
+  outputs = [ "out" "man" "info" ] ++ optional (!langJit && targetPlatform.config != "amdgcn-amdhsa") "lib";
 
   setOutputFlags = false;
 
@@ -356,6 +359,8 @@ pipe ((callFile ./common/builder.nix {}) ({
   '';
 } // optionalAttrs enableMultilib {
   dontMoveLib64 = true;
+} // optionalAttrs (targetPlatform.config == "amdgcn-amdhsa") {
+  newlibSrc = newlib.src;
 }
 ))
 ([

pkgs/development/compilers/llvm/common/common-let.nix

@@ -17,6 +17,7 @@ rec {
 
     # See llvm/cmake/config-ix.cmake.
     platforms =
+      ["amdgcn-amdhsa" ]++
       lib.platforms.aarch64 ++
       lib.platforms.arm ++
       lib.platforms.mips ++

pkgs/development/misc/newlib/default.nix

@@ -13,11 +13,11 @@
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "newlib";
-  version = "4.3.0.20230120";
+  version = "4.4.0.20231231";
 
   src = fetchurl {
     url = "ftp://sourceware.org/pub/newlib/newlib-${finalAttrs.version}.tar.gz";
-    sha256 = "sha256-g6Yqma9Z4465sMWO0JLuJNcA//Q6IsA+QzlVET7zUVA=";
+    sha256 = "sha256-DBZqOeG/CVHfr81olJ/g5LbTZYCB1igvOa7vxjEPLxM=";
   };
 
   patches = lib.optionals nanoizeNewlib [

pkgs/top-level/all-packages.nix

@@ -6080,6 +6080,17 @@ with pkgs;
 
   gccCrossLibcStdenv = overrideCC stdenvNoCC buildPackages.gccWithoutTargetLibc;
 
+  amdgcc = pkgsCross.amdgcn.buildPackages.gcc_latest.cc.override {
+    langCC = true;
+    # enableLTO = false;
+    # enableMultilib = true;
+    withoutTargetLibc = false;
+    enableShared = false;
+    noSysDirs = false;
+    libcCross = binutilsNoLibc.libc;
+    targetPackages.stdenv.cc.bintools = binutilsNoLibc;
+  };
+
   # The GCC used to build libc for the target platform. Normal gccs will be
   # built with, and use, that cross-compiled libc.
   gccWithoutTargetLibc = assert stdenv.targetPlatform != stdenv.hostPlatform; let
@@ -6118,6 +6129,13 @@ with pkgs;
 
   gcc_latest = gcc14;
 
+  gcc_offload = wrapCCWith {
+    cc = gcc_latest.cc.override {
+      enableOffload = true;
+    };
+    extraCompilerB = [ amdgcc ];
+  };
+
   libgccjit = gcc.cc.override {
     name = "libgccjit";
     langFortran = false;