Build nacl_helper_nonsfi with GN

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/ccache.gni")
 
@@ skipping 432 matching lines @@
           "-Wa,-mips64r6",
         ]
         ldflags += [ "-mips64r6" ]
       } else if (mips_arch_variant == "r2") {
         cflags += [
           "-mips64r2",
           "-Wa,-mips64r2",
         ]
         ldflags += [ "-mips64r2" ]
       }
+    } else if (current_cpu == "pnacl" && is_nacl_nonsfi) {
+      if (target_cpu == "x86" || target_cpu == "x64") {
+        cflags += [
+          "-arch",
+          "x86-32-nonsfi",
+          "--pnacl-bias=x86-32-nonsfi",
+          "--target=i686-unknown-nacl",
+        ]
+        ldflags += [
+          "-arch",
+          "x86-32-nonsfi",
+          "--target=i686-unknown-nacl",
+        ]
+      } else if (target_cpu == "arm") {
+        cflags += [
+          "-arch",
+          "arm-nonsfi",
+          "--pnacl-bias=arm-nonsfi",
+        ]
+        ldflags += [
+          "-arch",
+          "arm-nonsfi",
+        ]
+      }
     }
   }
 
   asmflags = cflags
 }
 
 # This provides options to tweak code generation that are necessary
 # for particular Chromium code or for working around particular
 # compiler bugs (or the combination of the two).
 config("compiler_codegen") {
@@ skipping 288 matching lines @@
     if (!is_nacl) {
       # Flags NaCl (Clang 3.7) does not recognize.
       cflags += [
         # TODO(thakis): Enable this, crbug.com/507717
         "-Wno-shift-negative-value",
 
         # TODO(thakis): Consider enabling this?
         "-Wno-bitfield-width",
       ]
     }
+
+    if (is_nacl_nonsfi) {

[brettw, 2015/10/23 09:38:13]

This block seems very strange to me. Why are we disabling all of these warnings
for this nacl variant? I don't see anything intrinsic in this build that
indicates we should disable things like sign compares or unused functions when
it works well otherwise.

[Petr Hosek, 2015/10/23 17:53:07]

I originally copied the configuration from Gyp but you're right, most of these
are not needed. Actually, it turned it's just the `-Wno-unused-function` and
`-Wno-sign-compare` which is really needed. The first one needs some fixes
inside seccomp-bfp, the second one needs a trivial fix on the NaCl side. I added
appropriate TODOs.

+      cflags += [
+        # Disables
+        "-Wno-c++11-extensions",
+        "-Wno-char-subscripts",
+        "-Wno-extra-semi",
+        "-Wno-unnamed-type-template-args",
+        "-Wno-unused-private-field",
+        "-Wno-unused-function",
+        "-Wno-sign-compare",
+      ]
+    }
   }
 }
 
 # chromium_code ---------------------------------------------------------------
 #
 # Toggles between higher and lower warnings for code that is (or isn't)
 # part of Chromium.
 
 config("chromium_code") {
   if (is_win) {
@@ skipping 412 matching lines @@
   if (symbol_level == 0) {
     configs = [ ":no_symbols" ]
   } else if (symbol_level == 1) {
     configs = [ ":minimal_symbols" ]
   } else if (symbol_level == 2) {
     configs = [ ":symbols" ]
   } else {
     assert(false)
   }
 }