Support Big Endian in ICU: part 3

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 2e63fa934603384ccd9cb5a8e6afaa416a3233cd..b6bf328dff40c5345e62d7b34578b5643c4b5868 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -582,19 +582,31 @@ if (icu_use_data_file) {
         sources = [
           "android/icudtl.dat",
         ]

[Michael Achenbach, 2016/07/26 09:18:56]

Readability suggestion: Maybe move the case distinction to toplevel and define
all required variables once (independent of data_file or not data_file). Like
that there won't be more case distinctions in the code below. E.g. once:

if (is_android) {
  data_bundle_source = ...
  data_bundle_out = ...
  data_assembly = ...
} else if (current_cpu == "mips" || current_cpu == "mips64") {
  ...
} else {
  ...
}

[jungshik at Google, 2016/07/26 19:58:14]

Thank you for the suggestion. I did what you proposed except that
'data_assembly' still needs to be if-icu-use-data-file=false block. Otherwise,
gn complains about an unused variable when icu_use_data_file=true. 

+      } else if (current_cpu == "mips" || current_cpu == "mips64") {
+        sources = [
+          "common/icudtb.dat",
+        ]
       } else {
         sources = [
           "common/icudtl.dat",
         ]
       }
 
-      outputs = [
-        "$root_out_dir/icudtl.dat",
-      ]
-
-      data = [
-        "$root_out_dir/icudtl.dat",
-      ]
+      if (current_cpu == "mips" || current_cpu == "mips64") {
+        outputs = [
+          "$root_out_dir/icudtb.dat",
+        ]
+        data = [
+          "$root_out_dir/icudtb.dat",
+        ]
+      } else {
+        outputs = [
+          "$root_out_dir/icudtl.dat",
+        ]
+        data = [
+          "$root_out_dir/icudtl.dat",
+        ]
+      }
     }
   }
 } else {

[Michael Achenbach, 2016/07/26 09:29:45]

Note that v8 isn't using this case anymore. I don't know who is. V8 uses data
file by default.

[jungshik at Google, 2016/07/26 19:58:14]

Yeah. I noticed that change made in v8 a few weeks ago. There are some consumers
of ICU that prefer to link icudata statically (headless blink for sure. Android
webview at least used to, but i"m not sure of its current status). 

@@ -613,27 +625,35 @@ if (icu_use_data_file) {
       ]
     }
   } else {
+    data_bundle = "common/icudtl.dat"
+    data_assembly = "$target_gen_dir/icudtl_dat.S"
+    if (is_android) {
+      data_bundle = "android/icudtl.dat"
+    }
+    else if (current_cpu == "mips" || current_cpu == "mips64") {
+      data_bundle = "common/icudtb.dat"
+      data_assembly = "$target_gen_dir/icudtb_dat.S"
+    }
+
+    action("make_data_assembly") {
+      script = "scripts/make_data_assembly.py"
+      inputs = [ data_bundle ]
+      outputs = [ data_assembly ]
+      args = [

[Michael Achenbach, 2016/07/26 09:18:56]

FYI: I assume the action is executed in the root_build_dir. Added:

print(data_bundle)
print(data_assembly)
print(root_build_dir)
print(rebase_path(data_bundle, root_build_dir))
print(rebase_path(data_assembly, root_build_dir))

Output for v8:

common/icudtl.dat
//out/exp/gen/third_party/icu/icudtl_dat.S
//out/exp
../../third_party/icu/common/icudtl.dat
gen/third_party/icu/icudtl_dat.S

[jungshik at Google, 2016/07/26 19:58:14]

Those values are as expected. Do you see any problem ? 

+        rebase_path(data_bundle, root_build_dir),
+        rebase_path(data_assembly, root_build_dir),
+      ]
+      if (is_mac) {
+        args += [ "--mac" ]
+      }
+    }
+
     source_set("icudata") {
-      # These are hand-generated, but will do for now.
-      #
       # TODO(GYP): Gyp has considerations here for QNX and for the host toolchain
       #  that have not been ported over.
-      if (is_linux) {
-        sources = [
-          "linux/icudtl_dat.S",
-        ]
-      } else if (is_mac) {
-        sources = [
-          "mac/icudtl_dat.S",
-        ]
-      } else if (is_android) {
-        sources = [
-          "android/icudtl_dat.S",
-        ]
-      } else {
-        assert(false, "No icu data for this platform")
-      }
+      sources = [ data_assembly, ]
       defines = [ "U_HIDE_DATA_SYMBOL" ]
+      deps = [ ":make_data_assembly", ]
     }
   }
 }