Use clang for snapshot_toolchain by default, except on ChromeOS.

snapshot_toolchain.gni

 # Copyright 2015 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 32 matching lines @@
 # validation.
 #
 # There are test cases for this code posted as an attachment to
 # https://crbug.com/625353.
 #
 # TODO(GYP): Currently only regular (non-cross) compiles, and cross-compiles
 # from x64 hosts to Intel, ARM, or MIPS targets, are implemented. Add support
 # for the other supported configurations.
 
 if (v8_snapshot_toolchain == "") {
-
   if (current_os == host_os && current_cpu == host_cpu) {
     # This is not a cross-compile, so build the snapshot with the current
     # toolchain.
     v8_snapshot_toolchain = current_toolchain
-
   } else if (current_os == host_os && current_cpu == "x86" &&
              host_cpu == "x64") {
     # This is an x64 -> x86 cross-compile, but x64 hosts can usually run x86
     # binaries built for the same OS, so build the snapshot with the current
     # toolchain here, too.
     v8_snapshot_toolchain = current_toolchain
-
   } else if (current_os == "win" && host_os == "mac" && is_clang) {
     # This is a mac -> win cross-compile, which is only supported w/ clang.
     v8_snapshot_toolchain = "//build/toolchain/mac:clang_${v8_current_cpu}"
-
   } else if (host_cpu == "x64") {
     # This is a cross-compile from an x64 host to either a non-Intel target
-    # cpu or a different target OS. Assume the same toolchain (Clang or GCC
-    # or MSVS) for target and host, unless this is an Android build, where
-    # Clang is always used on the host.
-    if (is_clang || is_android) {
+    # cpu or a different target OS. Clang will always be used by default on the
+    # host, unless this is a ChromeOS build, in which case the same toolchain
+    # (Clang or GCC) will be used for target and host by default.
+    if (is_chromeos && !is_clang) {
+      _clang = ""
+    } else {
       _clang = "clang_"
-    } else {
-      _clang = ""
     }
 
     if (v8_current_cpu == "x64" || v8_current_cpu == "x86") {
       _cpus = v8_current_cpu
     } else if (v8_current_cpu == "arm64" || v8_current_cpu == "mips64el") {
       _cpus = "x64_v8_${v8_current_cpu}"
     } else if (v8_current_cpu == "arm" || v8_current_cpu == "mipsel") {
       _cpus = "x86_v8_${v8_current_cpu}"
     } else {
       # This branch should not be reached; leave _cpus blank so the assert
       # below will fail.
       _cpus = ""
     }
 
     if (_cpus != "") {
       v8_snapshot_toolchain = "//build/toolchain/${host_os}:${_clang}${_cpus}"
     }
   }
 }
 
 assert(v8_snapshot_toolchain != "",
        "Do not know how to build a snapshot for $current_toolchain " +
-       "on $host_os $host_cpu")
+           "on $host_os $host_cpu")

[Dirk Pranke, 2016/08/22 23:08:45]

Was this indentation change intentional?

[slan, 2016/08/22 23:18:08]

That's what gn format wanted.