GN (Android): Make is_clang work for (at least for arm32)

There seem to be more compiler flags to tweak for other target
architectures, but with this I could at least build & run chrome_apk
with is_clang=true

BUG=402625

Review URL: https://codereview.chromium.org/1258923012

Cr-Commit-Position: refs/heads/master@{#342227}

3 files changed, 83 insertions, 24 deletions

diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
index fc5b392..337aaf5 100644
--- a/build/config/BUILDCONFIG.gn
+++ b/build/config/BUILDCONFIG.gn
@@ -574,7 +574,11 @@ if (is_win) {
   } else {
     assert(false, "Unknown host for android cross compile")
   }
-  set_default_toolchain("//build/toolchain/android:$current_cpu")
+  if (is_clang) {
+    set_default_toolchain("//build/toolchain/android:clang_$current_cpu")
+  } else {
+    set_default_toolchain("//build/toolchain/android:$current_cpu")
+  }
 } else if (is_linux) {
   if (is_clang) {
     host_toolchain = "//build/toolchain/linux:clang_$host_cpu"
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index f6cdd06..ffd3088 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -177,11 +177,14 @@ config("compiler") {
     # Stack protection.
     if (is_mac) {
       cflags += [ "-fstack-protector-all" ]
-    } else if (is_linux) {
-      cflags += [
-        "-fstack-protector",
-        "--param=ssp-buffer-size=4",
-      ]
+    } else if (is_posix && !is_chromeos && !is_nacl) {
+      # TODO(phajdan.jr): Use -fstack-protector-strong when our gcc supports it.
+      cflags += [ "--param=ssp-buffer-size=4" ]
+      if (is_android && (current_cpu == "arm64" || current_cpu == "x86")) {
+        cflags += [ "-fno-stack-protector" ]
+      } else {
+        cflags += [ "-fstack-protector" ]
+      }
     }
 
     # Linker warnings.
@@ -528,7 +531,15 @@ config("compiler") {
       "-funwind-tables",
       "-fno-short-enums",
     ]
-    if (!is_clang) {
+    if (is_clang) {
+      rebased_android_toolchain_root =
+          rebase_path(android_toolchain_root, root_build_dir)
+      cflags += [
+        # TODO(hans) Enable integrated-as (crbug.com/124610).
+        "-no-integrated-as",
+        "-B${rebased_android_toolchain_root}/bin",  # Else /usr/bin/as gets picked up.
+      ]
+    } else {
       # Clang doesn't support these flags.
       cflags += [ "-finline-limit=64" ]
     }
@@ -551,8 +562,7 @@ config("compiler") {
       ldflags += [ "-fuse-ld=gold" ]
       if (is_clang) {
         # Let clang find the ld.gold in the NDK.
-        ldflags += [ "--gcc-toolchain=" +
-                     rebase_path(android_toolchain_root, root_build_dir) ]
+        ldflags += [ "--gcc-toolchain=$rebased_android_toolchain_root" ]
       }
     }
 
@@ -578,11 +588,23 @@ config("compiler") {
 
     if (is_clang) {
       if (current_cpu == "arm") {
-        cflags += [ "-target arm-linux-androideabi" ]
-        ldflags += [ "-target arm-linux-androideabi" ]
+        cflags += [
+          "-target",
+          "arm-linux-androideabi",
+        ]
+        ldflags += [
+          "-target",
+          "arm-linux-androideabi",
+        ]
       } else if (current_cpu == "x86") {
-        cflags += [ "-target i686-linux-androideabi" ]
-        ldflags += [ "-target i686-linux-androideabi" ]
+        cflags += [
+          "-target",
+          "i686-linux-androideabi",
+        ]
+        ldflags += [
+          "-target",
+          "i686-linux-androideabi",
+        ]
       }
     }
   }
@@ -853,10 +875,13 @@ if (is_win) {
     default_warning_flags_cc += [
       # See comment for -Wno-c++11-narrowing.
       "-Wno-narrowing",
-
-      # TODO(thakis): Remove, http://crbug.com/263960
-      "-Wno-literal-suffix",
     ]
+    if (!is_clang) {
+      default_warning_flags_cc += [
+        # TODO(thakis): Remove, http://crbug.com/263960
+        "-Wno-literal-suffix",
+      ]
+    }
   }
 
   # Suppress warnings about ABI changes on ARM (Clang doesn't give this
diff --git a/build/toolchain/android/BUILD.gn b/build/toolchain/android/BUILD.gn
index 087f04b..867fa48 100644
--- a/build/toolchain/android/BUILD.gn
+++ b/build/toolchain/android/BUILD.gn
@@ -45,8 +45,21 @@ template("android_gcc_toolchain") {
       compiler_prefix = ""
     }
 
-    cc = compiler_prefix + tool_prefix + "gcc"
-    cxx = compiler_prefix + tool_prefix + "g++"
+    is_clang = invoker.is_clang
+    if (is_clang) {
+      if (use_clang_type_profiler) {
+        prefix = rebase_path("//third_party/llvm-allocated-type/Linux_x64/bin",
+                             root_build_dir)
+      } else {
+        prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
+                             root_build_dir)
+      }
+      cc = "${compiler_prefix}$prefix/clang"
+      cxx = "${compiler_prefix}$prefix/clang++"
+    } else {
+      cc = "${compiler_prefix}${tool_prefix}gcc"
+      cxx = "${compiler_prefix}${tool_prefix}g++"
+    }
     ar = tool_prefix + "ar"
     ld = cxx
     readelf = compiler_prefix + tool_prefix + "readelf"
@@ -80,7 +93,24 @@ template("android_gcc_toolchain") {
   }
 }
 
-android_gcc_toolchain("x86") {
+template("android_gcc_toolchains_helper") {
+  android_gcc_toolchain(target_name) {
+    android_ndk_sysroot = invoker.android_ndk_sysroot
+    android_ndk_lib_dir = invoker.android_ndk_lib_dir
+    tool_prefix = invoker.tool_prefix
+    toolchain_cpu = invoker.toolchain_cpu
+  }
+
+  android_gcc_toolchain("clang_$target_name") {
+    android_ndk_sysroot = invoker.android_ndk_sysroot
+    android_ndk_lib_dir = invoker.android_ndk_lib_dir
+    tool_prefix = invoker.tool_prefix
+    toolchain_cpu = invoker.toolchain_cpu
+    is_clang = true
+  }
+}
+
+android_gcc_toolchains_helper("x86") {
   android_ndk_sysroot = "$android_ndk_root/$x86_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
@@ -88,7 +118,7 @@ android_gcc_toolchain("x86") {
   toolchain_cpu = "x86"
 }
 
-android_gcc_toolchain("arm") {
+android_gcc_toolchains_helper("arm") {
   android_ndk_sysroot = "$android_ndk_root/$arm_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
@@ -96,7 +126,7 @@ android_gcc_toolchain("arm") {
   toolchain_cpu = "arm"
 }
 
-android_gcc_toolchain("mipsel") {
+android_gcc_toolchains_helper("mipsel") {
   android_ndk_sysroot = "$android_ndk_root/$mips_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
@@ -104,7 +134,7 @@ android_gcc_toolchain("mipsel") {
   toolchain_cpu = "mipsel"
 }
 
-android_gcc_toolchain("x64") {
+android_gcc_toolchains_helper("x64") {
   android_ndk_sysroot = "$android_ndk_root/$x86_64_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib64"
 
@@ -112,7 +142,7 @@ android_gcc_toolchain("x64") {
   toolchain_cpu = "x86_64"
 }
 
-android_gcc_toolchain("arm64") {
+android_gcc_toolchains_helper("arm64") {
   android_ndk_sysroot = "$android_ndk_root/$arm64_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib"
 
@@ -120,7 +150,7 @@ android_gcc_toolchain("arm64") {
   toolchain_cpu = "aarch64"
 }
 
-android_gcc_toolchain("mips64el") {
+android_gcc_toolchains_helper("mips64el") {
   android_ndk_sysroot = "$android_ndk_root/$mips64_android_sysroot_subdir"
   android_ndk_lib_dir = "usr/lib64"