gn: add support for clang for MIPS

build/config/android/BUILD.gn

 # 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/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/sysroot.gni")
 
 assert(is_android)
 
@@ skipping 15 matching lines @@
   ]
   ldflags = []
 
   if (!is_clang) {
     # Clang doesn't support these flags.
     cflags += [ "-finline-limit=64" ]
   }
   if (is_clang) {
     rebased_android_toolchain_root =
         rebase_path(android_toolchain_root, root_build_dir)
-    if (current_cpu == "arm") {
+    if (current_cpu == "arm" || current_cpu == "mipsel") {
       cflags += [
         # TODO(hans) Enable integrated-as (crbug.com/124610).
         "-no-integrated-as",
         "-B${rebased_android_toolchain_root}/bin",  # Else /usr/bin/as gets picked up.
       ]
     }
   }
 
   # Use gold for Android for most CPU architectures.
   if (current_cpu == "x86" || current_cpu == "x64" || current_cpu == "arm") {
     ldflags += [ "-fuse-ld=gold" ]
     if (is_clang) {
       # Let clang find the ld.gold in the NDK.
       ldflags += [ "--gcc-toolchain=$rebased_android_toolchain_root" ]
     }
 
     # Use -mstackrealign due to a bug on ia32 Jelly Bean.
     # See crbug.com/521527
     if (current_cpu == "x86") {
       cflags += [ "-mstackrealign" ]
     }
   }
 
+  if (current_cpu == "mipsel" && is_clang) {
+    # Let clang find the ld.bfd in the NDK.
+    ldflags += [ "--gcc-toolchain=$rebased_android_toolchain_root" ]
+  }
+
   ldflags += [
     "-Wl,--no-undefined",
 
     # Don't allow visible symbols from libgcc or libc++ to be
     # re-exported.
     "-Wl,--exclude-libs=libgcc.a",
     "-Wl,--exclude-libs=libc++_static.a",
 
     # Don't allow visible symbols from libraries that contain
     # assembly code with symbols that aren't hidden properly.
@@ skipping 14 matching lines @@
       abi_target = "i686-linux-androideabi"
     } else if (current_cpu == "arm64") {
       # Place holder for arm64 support, not tested.
       # TODO: Enable clang support for Android Arm64. http://crbug.com/539781
       abi_target = "aarch64-linux-androideabi"
     } else if (current_cpu == "x64") {
       # Place holder for x64 support, not tested.
       # TODO: Enable clang support for Android x64. http://crbug.com/539781
       abi_target = "x86_64-linux-androideabi"
     } else if (current_cpu == "mipsel") {
-      # Place holder for mips support, not tested.
-      abi_target = "mipsel-linux-androideabi"
+      abi_target = "mipsel-linux-android"
     } else if (current_cpu == "mips64el") {
       # Place holder for mips64 support, not tested.
       abi_target = "mips64el-linux-androideabi"
     } else {
       assert(false, "Architecture not supported")
     }
     cflags += [
       "-target",
       abi_target,
     ]
@@ skipping 33 matching lines @@
   defines = [ "__GNU_SOURCE=1" ]  # Necessary for clone().
   ldflags = [ "-nostdlib" ]
   lib_dirs = [ "$android_libcpp_root/libs/$android_app_abi" ]
 
   # The libc++ runtime library (must come first).
   if (is_component_build) {
     libs = [ "c++_shared" ]
   } else {
     libs = [ "c++_static" ]
   }
+
+  # libgcc must come before libdl for ld.bfd (MIPS)
+  if (current_cpu == "mipsel") {
+    libs += [
+      # ld linker is used for mips Android, and ld does not accept library
+      # absolute path prefixed by "-l"; Since libgcc does not exist in mips
+      # sysroot the proper library will be linked.
+      # TODO(gordanac): Remove once gold linker is used for mips Android.
+      "gcc",
+    ]
+  } else {
+    libs += [
+      # Manually link the libgcc.a that the cross compiler uses. This is
+      # absolute because the linker will look inside the sysroot if it's not.
+      rebase_path(android_libgcc_file),
+    ]
+  }
+
   libs += [
     "c",
     "dl",
     "m",
   ]
 
   if (is_clang) {
     # Work around incompatibilities between bionic and clang headers.
     defines += [
       "__compiler_offsetof=__builtin_offsetof",
       "nan=__builtin_nan",
     ]
   }
 
   # TODO(jdduke) Re-enable on mips after resolving linking
   # issues with libc++ (crbug.com/456380).
   if (current_cpu != "mipsel" && current_cpu != "mips64el") {
     ldflags += [ "-Wl,--warn-shared-textrel" ]
   }
 
-  if (current_cpu == "mipsel") {
-    libs += [
-      # ld linker is used for mips Android, and ld does not accept library
-      # absolute path prefixed by "-l"; Since libgcc does not exist in mips
-      # sysroot the proper library will be linked.
-      # TODO(gordanac): Remove once gold linker is used for mips Android.
-      "gcc",
-    ]
-  } else {
-    libs += [
-      # Manually link the libgcc.a that the cross compiler uses. This is
-      # absolute because the linker will look inside the sysroot if it's not.
-      rebase_path(android_libgcc_file),
-    ]
-  }
-
   # Clang with libc++ does not require an explicit atomic library reference.
   if (!is_clang) {
     libs += [ "atomic" ]
   }
 }
 
 config("executable_config") {
   cflags = [ "-fPIE" ]
   asmflags = [ "-fPIE" ]
   ldflags = [ "-pie" ]
@@ skipping 30 matching lines @@
 
     # Avoid errors with current NDK:
     # "third_party/android_tools/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/include/arm_neon.h:3426:3: error: argument must be a constant"
     "-finstrument-functions-exclude-file-list=arm_neon.h,SaturatedArithmeticARM.h",
   ]
   defines = [ "CYGPROFILE_INSTRUMENTATION=1" ]
 }
 
 config("no_cygprofile_instrumentation") {
 }