Initialize arm_float_abi and arm_fpu from sabi.json.

- The build/config/arm.gni is trying to guess the
 correct arm floating point ABI and sometimes get is wrong.
 We already have that specified in the sabi.json and we
 should just initialize it directly.

- Abstract out the sabi_variables reading in separate
 sabi.gni file.

b/235111527

Change-Id: Ic67a781e5e80c05e7f2f792f763bb5ac1c677cfa

build/config/arm.gni

@@ -4,6 +4,10 @@
 
 import("//build/config/v8_target_cpu.gni")
 
+if (is_starboard) {
+  import("//starboard/sabi/sabi.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
@@ -38,14 +42,19 @@ if (current_cpu == "arm" || v8_current_cpu == "arm") {
     arm_use_thumb = true
   }
 
-  if (current_os == "android" || target_os == "android") {
-    arm_float_abi = "softfp"
+  if (is_starboard) {
+    arm_float_abi = sabi_variables.floating_point_abi
+    arm_fpu = sabi_variables.floating_point_fpu
   } else {
-    declare_args() {
-      # The ARM floating point mode. This is either the string "hard", "soft",
-      # or "softfp". An empty string means to use the default one for the
-      # arm_version.
-      arm_float_abi = ""
+    if (current_os == "android" || target_os == "android") {
+      arm_float_abi = "softfp"
+    } else {
+      declare_args() {
+        # The ARM floating point mode. This is either the string "hard", "soft",
+        # or "softfp". An empty string means to use the default one for the
+        # arm_version.
+        arm_float_abi = ""
+      }
     }
   }
   assert(arm_float_abi == "" || arm_float_abi == "hard" ||
@@ -120,7 +129,12 @@ if (current_cpu == "arm" || v8_current_cpu == "arm") {
     }
   }
 } else if (current_cpu == "arm64" || v8_current_cpu == "arm64") {
-  # arm64 supports only "hard".
-  arm_float_abi = "hard"
+  if (is_starboard) {
+    arm_float_abi = sabi_variables.floating_point_abi
+    arm_fpu = sabi_variables.floating_point_fpu
+  } else {
+    # arm64 supports only "hard".
+    arm_float_abi = "hard"
+  }
   arm_use_neon = true
 }

starboard/build/config/sabi/BUILD.gn

@@ -12,9 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import("//starboard/sabi/sabi.gni")
+
 config("sabi") {
-  sabi_json = read_file(sabi_path, "json")
-  sabi_variables = sabi_json.variables
   forward_variables_from(sabi_variables, "*")
 
   arch_uppercase =

starboard/sabi/sabi.gni

@@ -0,0 +1,19 @@
+# Copyright 2021 The Cobalt Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Read the ABI configuration from the SABI json file and make it available
+# through a global variable.
+
+sabi_json = read_file(sabi_path, "json")
+sabi_variables = sabi_json.variables

third_party/boringssl/BUILD.gn

@@ -1,3 +1,4 @@
+import("//starboard/sabi/sabi.gni")
 import("//third_party/boringssl/buildfiles.gni")
 
 declare_args() {
@@ -98,8 +99,6 @@ static_library("crypto") {
     configs += [ "//starboard/build/config:speed" ]
 
     if (sb_is_evergreen) {
-      sabi_json = read_file(sabi_path, "json")
-      sabi_variables = sabi_json.variables
       calling_convention = sabi_variables.calling_convention
       if ((calling_convention != "aarch64" && calling_convention != "eabi" &&
            calling_convention != "sysv" && calling_convention != "windows") ||