gn: Default to softfp for V8 arm simulator builds

build/config/arm.gni

 # Copyright 2014 The Chromium Authors. 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/v8_target_cpu.gni")
 
 # These are primarily relevant in current_cpu == "arm" contexts, where
 # ARM code is being compiled.  But they can also be relevant in the
 # other contexts when the code will change its behavior based on the
 # cpu it wants to generate code for.
@@ skipping 37 matching lines @@
     }
     arm_fpu = "vfp"
     arm_use_thumb = false
   } else if (arm_version == 7) {
     arm_arch = "armv7-a"
     if (arm_tune == "") {
       arm_tune = "generic-armv7-a"
     }
 
     if (arm_float_abi == "") {
       if (current_os == "android" || target_os == "android") {

[jochen (gone - plz use gerrit), 2016/07/25 15:00:32]

why not if (current_os == "chromeos" || target_os == "chromeos") {
 arm_float_abi = "hardfp"
} else {
 arm_float_abi = "softfp"
}

[Michael Achenbach, 2016/07/25 15:17:58]

When s/hardfp/hard this should be the same according to my assumptions. But I
don't trust my assumptions and I wanted to avoid flipping something that
shouldn't be flipped. So the other version is a bit more defensive. What about
linux builds with arm?

Dirk, any thoughts?

[Dirk Pranke, 2016/07/25 17:14:34]

I think the current_cpu != v8_current_cpu check should be enough, so this change
should be fine. I'm a little reluctant to have linux not match CrOS by default,
since the main reason we support linux arm is to be closer to CrOS.

         arm_float_abi = "softfp"
+      } else if (current_os == "linux" && current_cpu != v8_current_cpu) {
+        # Default to the same as Android for V8 simulator builds.
+        arm_float_abi = "softfp"
       } else {
         arm_float_abi = "hard"
       }
     }
 
     if (arm_use_neon) {
       arm_fpu = "neon"
     } else {
       arm_fpu = "vfpv3-d16"
     }
@@ skipping 15 matching lines @@
       arm_fpu = "neon"
     } else {
       arm_fpu = "vfpv3-d16"
     }
   }
 } else if (current_cpu == "arm64" || v8_current_cpu == "arm64") {
   # arm64 supports only "hard".
   arm_float_abi = "hard"
   arm_use_neon = true
 }