Reland "Revert "Add an --os=fuchsia option to build.py:""

This reverts commit d39d4d0d55.

Reason for revert: Relanding with fix

Change-Id: I6d6911b6cdc578a3b576b237db94c7f1db9824b9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151600
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Liam Appelbe <liama@google.com>

DEPS

@@ -470,6 +470,17 @@ deps = {
       "dep_type": "cipd",
   },
 
+  Var("dart_root") + "/third_party/fuchsia/sdk/linux": {
+    "packages": [
+      {
+      "package": "fuchsia/sdk/gn/linux-amd64",
+      "version": "git_revision:8d5242d4f6ff8b7634b492700e60b0fd09abefa3"
+      }
+    ],
+    "condition": 'host_os == "linux" and host_cpu == "x64"',
+    "dep_type": "cipd",
+  },
+
   Var("dart_root") + "/pkg/front_end/test/fasta/types/benchmark_data": {
     "packages": [
       {

build/config/BUILDCONFIG.gn

@@ -196,6 +196,16 @@ if (current_os == "win") {
   is_nacl = false
   is_posix = true
   is_win = false
+} else if (current_os == "fuchsia") {
+  is_android = false
+  is_chromeos = false
+  is_fuchsia = true
+  is_ios = false
+  is_linux = false
+  is_mac = false
+  is_nacl = false
+  is_posix = true
+  is_win = false
 }
 
 # =============================================================================
@@ -384,6 +394,11 @@ if (is_win) {
 } else if (is_mac) {
   host_toolchain = "//build/toolchain/mac:clang_x64"
   set_default_toolchain(host_toolchain)
+} else if (is_fuchsia) {
+  assert(host_os == "linux")
+  assert(host_cpu == "x64")
+  host_toolchain = "//build/toolchain/linux:clang_$host_cpu"
+  set_default_toolchain("//build/toolchain/fuchsia")
 }
 
 # ==============================================================================

build/config/compiler/BUILD.gn

@@ -243,7 +243,7 @@ config("compiler") {
   # 3. When using the sanitizers.
   # Otherwise there is a performance hit, in particular on ia32.
   if (is_android || is_asan || is_lsan || is_msan || is_tsan || is_ubsan ||
-      (is_linux && current_cpu != "x86")) {
+      (is_linux && current_cpu != "x86") || is_fuchsia) {
     cflags += [ "-fPIC" ]
     ldflags += [ "-fPIC" ]
   }
@@ -276,6 +276,8 @@ config("compiler") {
   if (is_win) {
     # Up-to-date toolchain MSVC doesn't support c++11 flag any longer.
     cc_std = [ "/std:c++14" ]
+  } else if (is_fuchsia) {
+    cc_std = [ "-std=c++17" ]
   } else {
     cc_std = [ "-std=c++11" ]
   }

build/fuchsia/sdk.gni

@@ -0,0 +1,10 @@
+# Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+declare_args() {
+  using_fuchsia_gn_sdk = true
+  fuchsia_sdk_root = "//third_party/fuchsia/sdk/$host_os"
+  fuchsia_sdk_path = "//third_party/fuchsia/sdk/$host_os"
+  fuchsia_toolchain_path = "//third_party/fuchsia/toolchain/$host_os"
+}

build/toolchain/fuchsia/BUILD.gn

@@ -0,0 +1,164 @@
+# Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+import("//build/config/sysroot.gni")
+import("//build/toolchain/ccache.gni")
+import("//build/toolchain/gcc_toolchain.gni")
+import("//build/toolchain/goma.gni")
+
+if (use_goma) {
+  assert(!use_ccache, "Goma and ccache can't be used together.")
+  compiler_prefix = "$goma_dir/gomacc "
+} else if (use_ccache) {
+  compiler_prefix = "ccache "
+} else {
+  compiler_prefix = ""
+}
+
+toolchain("fuchsia") {
+  assert(target_cpu == "x64", "We currently only support 'x64' for fuchsia.")
+  toolchain_bin =
+      rebase_path("//buildtools/$host_os-$target_cpu/clang/bin", root_out_dir)
+  fuchsia_sdk = rebase_path("//third_party/fuchsia/sdk/$host_os", root_out_dir)
+
+  # We can't do string interpolation ($ in strings) on things with dots in
+  # them. To allow us to use $cc below, for example, we create copies of
+  # these values in our scope.
+  cc = "${toolchain_bin}/clang"
+  cxx = "${toolchain_bin}/clang++"
+  ar = "${toolchain_bin}/llvm-ar"
+  ld = "${toolchain_bin}/clang++"
+  readelf = "${toolchain_bin}/llvm-readelf"
+  nm = "${toolchain_bin}/llvm-nm"
+  strip = "${toolchain_bin}/llvm-strip"
+
+  target_triple_flags = "--target=x86_64-fuchsia"
+  sysroot_flags = "--sysroot ${fuchsia_sdk}/arch/${target_cpu}/sysroot"
+  lto_flags = ""
+
+  # These library switches can apply to all tools below.
+  lib_switch = "-l"
+  lib_dir_switch = "-L"
+
+  tool("cc") {
+    depfile = "{{output}}.d"
+    command = "$compiler_prefix $cc -MD -MF $depfile $target_triple_flags $sysroot_flags $lto_flags {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
+    depsformat = "gcc"
+    description = "CC {{output}}"
+    outputs =
+        [ "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o" ]
+  }
+
+  tool("cxx") {
+    depfile = "{{output}}.d"
+    command = "$compiler_prefix $cxx -MD -MF $depfile $target_triple_flags $sysroot_flags $lto_flags {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}} -c {{source}} -o {{output}}"
+    depsformat = "gcc"
+    description = "CXX {{output}}"
+    outputs =
+        [ "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o" ]
+  }
+
+  tool("asm") {
+    depfile = "{{output}}.d"
+    command = "$compiler_prefix $cc -MD -MF $depfile $target_triple_flags $sysroot_flags $lto_flags {{defines}} {{include_dirs}} {{asmflags}} {{cflags}} {{cflags_c}} -c {{source}} -o {{output}}"
+    depsformat = "gcc"
+    description = "ASM {{output}}"
+    outputs =
+        [ "{{source_out_dir}}/{{target_output_name}}.{{source_name_part}}.o" ]
+  }
+
+  tool("alink") {
+    rspfile = "{{output}}.rsp"
+    command = "rm -f {{output}} && $ar rcs {{output}} @$rspfile"
+    description = "AR {{output}}"
+    rspfile_content = "{{inputs}}"
+    outputs =
+        [ "{{target_out_dir}}/{{target_output_name}}{{output_extension}}" ]
+    default_output_extension = ".a"
+    output_prefix = "lib"
+  }
+
+  tool("solink") {
+    soname = "{{target_output_name}}{{output_extension}}"  # e.g. "libfoo.so".
+    sofile = "{{root_out_dir}}/$soname"  # Possibly including toolchain dir.
+    unstripped_sofile =
+        "{{root_out_dir}}/so.unstripped/$soname"  # Possibly including toolchain
+                                                  # dir.
+    rspfile = sofile + ".rsp"
+
+    # These variables are not built into GN but are helpers that implement
+    # (1) linking to produce a .so, (2) extracting the symbols from that file
+    # to a temporary file, (3) if the temporary file has differences from the
+    # existing .TOC file, overwrite it, otherwise, don't change it.
+    tocfile = sofile + ".TOC"
+    temporary_tocname = sofile + ".tmp"
+    link_command = "$compiler_prefix $ld $target_triple_flags $sysroot_flags $lto_flags -shared {{ldflags}} -o $unstripped_sofile -Wl,--build-id -Wl,-soname=$soname @$rspfile"
+    toc_command = "{ $readelf -d $unstripped_sofile | grep SONAME ; $nm -gD -f posix $unstripped_sofile | cut -f1-2 -d' '; } > $temporary_tocname"
+    replace_command = "if ! cmp -s $temporary_tocname $tocfile; then mv $temporary_tocname $tocfile; fi"
+    strip_command = "$strip -o $sofile $unstripped_sofile"
+
+    command =
+        "$link_command && $toc_command && $replace_command && $strip_command"
+    rspfile_content = "-Wl,--whole-archive {{inputs}} {{solibs}} -Wl,--no-whole-archive {{libs}}"
+
+    description = "SOLINK $sofile"
+
+    default_output_extension = ".so"
+
+    output_prefix = "lib"
+
+    # Since the above commands only updates the .TOC file when it changes, ask
+    # Ninja to check if the timestamp actually changed to know if downstream
+    # dependencies should be recompiled.
+    restat = true
+
+    # Tell GN about the output files. It will link to the sofile but use the
+    # tocfile for dependency management.
+    outputs = [
+      sofile,
+      unstripped_sofile,
+      tocfile,
+    ]
+
+    link_output = sofile
+    depend_output = tocfile
+  }
+
+  tool("link") {
+    exename = "{{target_output_name}}{{output_extension}}"
+    outfile = "{{root_out_dir}}/$exename"
+    rspfile = "$outfile.rsp"
+    unstripped_outfile = "{{root_out_dir}}/exe.stripped/$exename"
+    command = "$compiler_prefix $ld $target_triple_flags $sysroot_flags $lto_flags {{ldflags}} -o $unstripped_outfile -Wl,--build-id -Wl,--start-group @$rspfile {{solibs}} -Wl,--end-group {{libs}} && ${strip} -o $outfile $unstripped_outfile"
+    description = "LINK $outfile"
+    rspfile_content = "{{inputs}}"
+    outputs = [
+      unstripped_outfile,
+      outfile,
+    ]
+  }
+
+  tool("stamp") {
+    command = "touch {{output}}"
+    description = "STAMP {{output}}"
+  }
+
+  tool("copy") {
+    command = "ln -f {{source}} {{output}} 2>/dev/null || (rm -rf {{output}} && cp -af {{source}} {{output}})"
+    description = "COPY {{source}} {{output}}"
+  }
+
+  # When invoking this toolchain not as the default one, these args will be
+  # passed to the build. They are ignored when this is the default toolchain.
+  toolchain_args = {
+    current_cpu = target_cpu
+    current_os = target_os
+
+    # These values need to be passed through unchanged.
+    target_os = target_os
+    target_cpu = target_cpu
+
+    is_clang = true
+  }
+}

runtime/BUILD.gn

@@ -136,7 +136,10 @@ config("dart_config") {
   }
 
   if (is_fuchsia) {
-    if (using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      lib_dirs = [ "../out/DebugFuchsiaX64/lib" ]
+    }
+    if (using_fuchsia_gn_sdk || using_fuchsia_sdk) {
       # TODO(chinmaygarde): Currenty these targets need to be build in the
       # Fuchsia tree as well as outside it using the SDK. However, not all
       # Fuchsia features are available in the SDK. As these features are added,
@@ -223,7 +226,12 @@ library_for_all_configs("libdart") {
     defines = [ "DART_ENABLE_WASM" ]
   }
   if (is_fuchsia) {
-    if (using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      extra_deps += [
+        "$fuchsia_sdk_root/pkg/fdio",
+        "$fuchsia_sdk_root/pkg/trace-engine",
+      ]
+    } else if (using_fuchsia_sdk) {
       extra_deps += [
         "$fuchsia_sdk_root/pkg:fdio",
         "$fuchsia_sdk_root/pkg:trace-engine",

runtime/bin/BUILD.gn

@@ -42,7 +42,9 @@ template("build_libdart_builtin") {
     public_configs = [ ":libdart_builtin_config" ]
     deps = []
     if (is_fuchsia) {
-      if (using_fuchsia_sdk) {
+      if (using_fuchsia_gn_sdk) {
+        public_deps = [ "$fuchsia_sdk_root/pkg/fdio" ]
+      } else if (using_fuchsia_sdk) {
         public_deps = [ "$fuchsia_sdk_root/pkg:fdio" ]
       } else {
         public_deps = [ "//zircon/public/lib/fdio" ]
@@ -314,7 +316,13 @@ template("build_gen_snapshot_dart_io") {
     deps = []
 
     if (is_fuchsia) {
-      if (using_fuchsia_sdk) {
+      if (using_fuchsia_gn_sdk) {
+        deps += [
+          "$fuchsia_sdk_root/fidl/fuchsia.netstack",
+          "$fuchsia_sdk_root/pkg/sys_cpp",
+        ]
+        public_deps = [ "$fuchsia_sdk_root/pkg/fdio" ]
+      } else if (using_fuchsia_sdk) {
         deps += [
           "$fuchsia_sdk_root/fidl:fuchsia.netstack",
           "$fuchsia_sdk_root/pkg:sys_cpp",
@@ -450,7 +458,13 @@ template("dart_io") {
     deps += [ "//third_party/boringssl" ]
 
     if (is_fuchsia) {
-      if (using_fuchsia_sdk) {
+      if (using_fuchsia_gn_sdk) {
+        deps += [
+          "$fuchsia_sdk_root/fidl/fuchsia.netstack",
+          "$fuchsia_sdk_root/pkg/sys_cpp",
+        ]
+        public_deps = [ "$fuchsia_sdk_root/pkg/fdio" ]
+      } else if (using_fuchsia_sdk) {
         deps += [
           "$fuchsia_sdk_root/fidl:fuchsia.netstack",
           "$fuchsia_sdk_root/pkg:sys_cpp",
@@ -779,7 +793,9 @@ template("dart_executable") {
       # have them. They are needed for running Fuchsia binaries built for the
       # host.
       if (is_linux) {
-        configs += [ "../../build/config/gcc:executable_ldconfig" ]
+        # TODO(liama): Commenting this line out because it causes problems for
+        # --os=fuchsia. If no one complains, remove it.
+        # configs += [ "../../build/config/gcc:executable_ldconfig" ]
       } else if (is_mac) {
         configs += [ "../../build/config/mac:mac_dynamic_flags" ]
       }
@@ -1007,7 +1023,11 @@ executable("run_vm_tests") {
   }
 
   if (is_fuchsia) {
-    if (!using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      include_dirs += [ "$fuchsia_sdk_path/pkg/trace-engine/include" ]
+      libs = [ "zircon" ]
+    }
+    if (!using_fuchsia_gn_sdk && !using_fuchsia_sdk) {
       deps += [ "//zircon/system/ulib/trace" ]
     }
   }

runtime/bin/process_fuchsia.cc

@@ -744,7 +744,9 @@ class ProcessStarter {
     }
     actions[3] = {
       .action = FDIO_SPAWN_ACTION_SET_NAME,
-      .name.data = program_arguments_[0],
+      .name = {
+        .data = program_arguments_[0],
+      },
     };
 
     // Then fill in the namespace actions.
@@ -752,8 +754,10 @@ class ProcessStarter {
       for (size_t i = 0; i < flat_ns->count; i++) {
         actions[fixed_actions_cnt + i] = {
           .action = FDIO_SPAWN_ACTION_ADD_NS_ENTRY,
-          .ns.prefix = flat_ns->path[i],
-          .ns.handle = flat_ns->handle[i],
+          .ns = {
+            .prefix = flat_ns->path[i],
+            .handle = flat_ns->handle[i],
+          },
         };
       }
       free(flat_ns);

runtime/bin/snapshot_utils.cc

@@ -201,7 +201,9 @@ static AppSnapshot* TryReadAppSnapshotElf(
                 *isolate_data_buffer = nullptr,
                 *isolate_instructions_buffer = nullptr;
   Dart_LoadedElf* handle = nullptr;
+#if !defined(HOST_OS_FUCHSIA)
   if (force_load_elf_from_memory) {
+#endif
     File* const file =
         File::Open(/*namespc=*/nullptr, script_name, File::kRead);
     if (file == nullptr) return nullptr;
@@ -216,11 +218,13 @@ static AppSnapshot* TryReadAppSnapshotElf(
                             &isolate_data_buffer, &isolate_instructions_buffer);
     delete memory;
     file->Release();
+#if !defined(HOST_OS_FUCHSIA)
   } else {
     handle = Dart_LoadELF(script_name, file_offset, &error, &vm_data_buffer,
                           &vm_instructions_buffer, &isolate_data_buffer,
                           &isolate_instructions_buffer);
   }
+#endif
   if (handle == nullptr) {
     Syslog::PrintErr("Loading failed: %s\n", error);
     return nullptr;

runtime/platform/BUILD.gn

@@ -17,7 +17,9 @@ library_for_all_configs("libdart_platform") {
   extra_deps = []
 
   if (is_fuchsia) {
-    if (using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      extra_deps += [ "$fuchsia_sdk_root/pkg/sys_cpp" ]
+    } else if (using_fuchsia_sdk) {
       extra_deps += [ "$fuchsia_sdk_root/pkg:sys_cpp" ]
     } else {
       extra_deps += [ "//sdk/lib/sys/cpp" ]

runtime/vm/BUILD.gn

@@ -72,7 +72,16 @@ library_for_all_configs("libdart_vm") {
     "//third_party/icu:icuuc",
   ]
   if (is_fuchsia) {
-    if (using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      extra_deps = [
+        "$fuchsia_sdk_root/fidl/fuchsia.deprecatedtimezone",
+        "$fuchsia_sdk_root/pkg/inspect",
+        "$fuchsia_sdk_root/pkg/inspect_service_cpp",
+        "$fuchsia_sdk_root/pkg/sys_cpp",
+        "$fuchsia_sdk_root/pkg/sys_inspect_cpp",
+        "$fuchsia_sdk_root/pkg/trace-engine",
+      ]
+    } else if (using_fuchsia_sdk) {
       extra_deps = [
         "$fuchsia_sdk_root/fidl:fuchsia.deprecatedtimezone",
         "$fuchsia_sdk_root/pkg:inspect",
@@ -114,7 +123,9 @@ library_for_all_configs_with_compiler("libdart_compiler") {
   sources = rebase_path(compiler_sources, ".", "./compiler/")
   include_dirs = [ ".." ]
   if (is_fuchsia) {
-    if (using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      extra_deps = [ "$fuchsia_sdk_root/pkg/trace-engine" ]
+    } else if (using_fuchsia_sdk) {
       extra_deps = [ "$fuchsia_sdk_root/pkg:trace-engine" ]
     } else {
       extra_deps = [
@@ -128,7 +139,9 @@ library_for_all_configs_with_compiler("libdart_compiler") {
 library_for_all_configs("libdart_lib") {
   target_type = "source_set"
   if (is_fuchsia) {
-    if (using_fuchsia_sdk) {
+    if (using_fuchsia_gn_sdk) {
+      extra_deps = [ "$fuchsia_sdk_root/pkg/trace-engine" ]
+    } else if (using_fuchsia_sdk) {
       extra_deps = [ "$fuchsia_sdk_root/pkg:trace-engine" ]
     } else {
       extra_deps = [

sdk/BUILD.gn

@@ -332,7 +332,7 @@ if (target_cpu == "x64") {
       ignore_patterns = "{}"
     },
   ]
-  if (is_linux || is_android) {
+  if (is_linux || is_android || is_fuchsia) {
     copy_tree_specs += [
       {
         target = "copy_libtensorflowlite_c"

tools/build.py

@@ -59,7 +59,7 @@ def BuildOptions():
     result.add_option(
         "--os",
         help='Target OSs (comma-separated).',
-        metavar='[all,host,android]',
+        metavar='[all,host,android,fuchsia]',
         default='host')
     result.add_option(
         "--sanitizer",
@@ -88,7 +88,7 @@ def ProcessOptions(options, args):
     if options.mode == 'all':
         options.mode = 'debug,release,product'
     if options.os == 'all':
-        options.os = 'host,android'
+        options.os = 'host,android,fuchsia'
     if options.sanitizer == 'all':
         options.sanitizer = 'none,asan,lsan,msan,tsan,ubsan'
     options.mode = options.mode.split(',')
@@ -110,13 +110,12 @@ def ProcessOptions(options, args):
             return False
     options.os = [ProcessOsOption(os_name) for os_name in options.os]
     for os_name in options.os:
-        if not os_name in ['android', 'freebsd', 'linux', 'macos', 'win32']:
+        if not os_name in [
+                'android', 'freebsd', 'linux', 'macos', 'win32', 'fuchsia'
+        ]:
             print("Unknown os %s" % os_name)
             return False
-        if os_name != HOST_OS:
-            if os_name != 'android':
-                print("Unsupported target os %s" % os_name)
-                return False
+        if os_name == 'android':
             if not HOST_OS in ['linux', 'macos']:
                 print("Cross-compilation to %s is not supported on host os %s."
                       % (os_name, HOST_OS))
@@ -135,6 +134,19 @@ def ProcessOptions(options, args):
                     "For android builds you must specify a target, such as 'runtime'."
                 )
                 return False
+        elif os_name == 'fuchsia':
+            if HOST_OS != 'linux':
+                print("Cross-compilation to %s is not supported on host os %s."
+                      % (os_name, HOST_OS))
+                return False
+            if arch != 'x64':
+                print(
+                    "Cross-compilation to %s is not supported for architecture %s."
+                    % (os_name, arch))
+                return False
+        elif os_name != HOST_OS:
+            print("Unsupported target os %s" % os_name)
+            return False
     return True
 
 

tools/gn.py

@@ -281,7 +281,7 @@ def ProcessOptions(args):
     if args.mode == 'all':
         args.mode = 'debug,release,product'
     if args.os == 'all':
-        args.os = 'host,android'
+        args.os = 'host,android,fuchsia'
     if args.sanitizer == 'all':
         args.sanitizer = 'none,asan,lsan,msan,tsan,ubsan'
     args.mode = args.mode.split(',')
@@ -302,13 +302,12 @@ def ProcessOptions(args):
             return False
     oses = [ProcessOsOption(os_name) for os_name in args.os]
     for os_name in oses:
-        if not os_name in ['android', 'freebsd', 'linux', 'macos', 'win32']:
+        if not os_name in [
+                'android', 'freebsd', 'linux', 'macos', 'win32', 'fuchsia'
+        ]:
             print("Unknown os %s" % os_name)
             return False
-        if os_name != HOST_OS:
-            if os_name != 'android':
-                print("Unsupported target os %s" % os_name)
-                return False
+        if os_name == 'android':
             if not HOST_OS in ['linux', 'macos']:
                 print("Cross-compilation to %s is not supported on host os %s."
                       % (os_name, HOST_OS))
@@ -320,6 +319,19 @@ def ProcessOptions(args):
                     "Cross-compilation to %s is not supported for architecture %s."
                     % (os_name, arch))
                 return False
+        elif os_name == 'fuchsia':
+            if HOST_OS != 'linux':
+                print("Cross-compilation to %s is not supported on host os %s."
+                      % (os_name, HOST_OS))
+                return False
+            if arch != 'x64':
+                print(
+                    "Cross-compilation to %s is not supported for architecture %s."
+                    % (os_name, arch))
+                return False
+        elif os_name != HOST_OS:
+            print("Unsupported target os %s" % os_name)
+            return False
     if HOST_OS != 'win' and args.use_crashpad:
         print("Crashpad is only supported on Windows")
         return False
@@ -366,7 +378,7 @@ def parse_args(args):
         '--os',
         type=str,
         help='Target OSs (comma-separated).',
-        metavar='[all,host,android]',
+        metavar='[all,host,android,fuchsia]',
         default='host')
     common_group.add_argument(
         '--sanitizer',

tools/utils.py

@@ -311,7 +311,7 @@ def IsCrossBuild(target_os, arch):
 
 
 def GetBuildConf(mode, arch, conf_os=None, sanitizer=None):
-    if conf_os == 'android':
+    if conf_os != GuessOS() and conf_os != "host":
         return '%s%s%s' % (GetBuildMode(mode), conf_os.title(), arch.upper())
     else:
         # Ask for a cross build if the host and target architectures don't match.