EFR32: Add hex binary to build output (#12809)

Add a gn action which provides a hex binary in addition to the s37.
The hex binary can be flashed with jlink and doesn't require
commander to be installed, and is therefore an easier format for use
in test automation.

build/toolchain/flashable_executable.gni

@@ -96,14 +96,21 @@ template("flashable_executable") {
     # The executable is the final target.
     final_target = executable_target
   }
+
+  if (defined(invoker.flashbundle_name)) {
+    flashbundle_name = invoker.flashbundle_name
+  } else {
+    flashbundle_name = "${target_name}.flashbundle.txt"
+  }
+
   group(target_name) {
     data_deps = [ ":$final_target" ]
 
     if (defined(invoker.data_deps)) {
       data_deps += invoker.data_deps
     }
 
-    write_runtime_deps = "${root_out_dir}/${target_name}.flashbundle.txt"
+    write_runtime_deps = "${root_out_dir}/${flashbundle_name}"
   }
 
   if (defined(invoker.objcopy_image_name)) {

scripts/build/builders/efr32.py

@@ -118,21 +118,18 @@ def GnBuildArgs(self):
         return args
 
     def build_outputs(self):
-        items = {
-            '%s.out' % self.app.AppNamePrefix():
-                os.path.join(self.output_dir, '%s.out' %
-                             self.app.AppNamePrefix()),
-            '%s.out.map' % self.app.AppNamePrefix():
-                os.path.join(self.output_dir,
-                             '%s.out.map' % self.app.AppNamePrefix()),
-        }
+        items = {}
+        for extension in ["out", "out.map", "hex"]:
+            name = '%s.%s' % (self.app.AppNamePrefix(), extension)
+            items[name] = os.path.join(self.output_dir, name)
 
         if self.app == Efr32App.UNIT_TEST:
             # Include test runner python wheels
             for root, dirs, files in os.walk(os.path.join(self.output_dir, 'chip_nl_test_runner_wheels')):
                 for file in files:
                     items["chip_nl_test_runner_wheels/" +
                           file] = os.path.join(root, file)
+
         # Figure out flash bundle files and build accordingly
         with open(os.path.join(self.output_dir, self.app.FlashBundleName())) as f:
             for line in f.readlines():

third_party/efr32_sdk/efr32_executable.gni

@@ -44,8 +44,28 @@ template("efr32_executable") {
   flashing_script_name = output_base_name + ".flash.py"
   flashing_options = [ "efr32" ]
 
-  flashable_executable(target_name) {
+  flash_target_name = target_name + ".flash_executable"
+  flashbundle_name = "${target_name}.flashbundle.txt"
+  flashable_executable(flash_target_name) {
     forward_variables_from(invoker, "*")
     data_deps = [ ":${flashing_runtime_target}" ]
   }
+
+  # Add a target which generates the hex file in addition to s37.
+  executable_target = "$flash_target_name.executable"
+  hex_image_name = output_base_name + ".hex"
+  hex_target_name = target_name + ".hex"
+  objcopy_convert(hex_target_name) {
+    conversion_input = "${root_out_dir}/${invoker.output_name}"
+    conversion_output = "${root_out_dir}/${hex_image_name}"
+    conversion_target_format = "ihex"
+    deps = [ ":$executable_target" ]
+  }
+
+  group(target_name) {
+    deps = [
+      ":$flash_target_name",
+      ":$hex_target_name",
+    ]
+  }
 }