Reland of Merge android's use_gold settings with the main use_gold GN arg logic

This also fixes Android setting -Wl,--icf=all in a different spot.

Reason for reland:
Removed --icf=safe for x86

BUG=606749,576197,611668

Review-Url: https://codereview.chromium.org/1996433002
Cr-Original-Commit-Position: refs/heads/master@{#394655}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 10371eae8d24d0ea7efa880571d51d62ce8f197c

config/android/BUILD.gn

@@ -4,12 +4,9 @@
 
 import("//build/config/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
-import("//build/config/sysroot.gni")
 
 assert(is_android)
 
-use_gold = current_cpu == "x86" || current_cpu == "x64" || current_cpu == "arm"
-
 # This is included by reference in the //build/config/compiler config that
 # is applied to all targets. It is here to separate out the logic that is
 # Android-only.
@@ -25,12 +22,7 @@ config("compiler") {
     # does. Define them here instead.
     "HAVE_SYS_UIO_H",
   ]
-  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)
@@ -42,29 +34,12 @@ config("compiler") {
         "-B${rebased_android_toolchain_root}/bin",  # Else /usr/bin/as gets picked up.
       ]
     }
+  } else {
+    # Clang doesn't support these flags.
+    cflags += [ "-finline-limit=64" ]
   }
 
-  # Use gold for Android for most CPU architectures.
-  if (use_gold) {
-    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 += [
+  ldflags = [
     "-Wl,--build-id=sha1",
     "-Wl,--no-undefined",
 
@@ -78,12 +53,6 @@ config("compiler") {
     # http://crbug.com/448386
     "-Wl,--exclude-libs=libvpx_assembly_arm.a",
   ]
-  if (current_cpu == "arm" && !use_order_profiling) {
-    ldflags += [
-      # Enable identical code folding to reduce size.
-      "-Wl,--icf=all",
-    ]
-  }
 
   if (is_clang) {
     if (current_cpu == "arm") {
@@ -181,12 +150,6 @@ config("executable_config") {
   cflags = [ "-fPIE" ]
   asmflags = [ "-fPIE" ]
   ldflags = [ "-pie" ]
-
-  if (!use_gold) {
-    # ld needs help finding libraries when linking.
-    _rebased_sysroot = rebase_path(sysroot, root_build_dir)
-    ldflags += [ "-Wl,-rpath-link=.:$_rebased_sysroot/usr/lib" ]
-  }
 }
 
 config("hide_native_jni_exports") {

config/compiler/BUILD.gn

@@ -46,11 +46,6 @@ declare_args() {
   # Requires profiling to be set to true.
   enable_full_stack_frames_for_profiling = false
 
-  # Whether to use the gold linker from binutils instead of lld or bfd.
-  use_gold =
-      !use_lld && is_linux &&
-      (current_cpu == "x64" || current_cpu == "x86" || current_cpu == "arm")
-
   # When we are going to use gold we need to find it.
   # This is initialized below, after use_gold might have been overridden.
   gold_path = false
@@ -303,24 +298,35 @@ config("compiler") {
   if (is_posix && use_lld && !is_nacl) {
     ldflags += [ "-fuse-ld=lld" ]
   } else if (use_gold) {
-    ldflags += [
-      "-B$gold_path",
+    ldflags += [ "-fuse-ld=gold" ]
+    if (is_android) {
+      if (is_clang) {
+        _rebased_android_toolchain_root =
+            rebase_path(android_toolchain_root, root_build_dir)
 
-      # Newer gccs and clangs support -fuse-ld, use the flag to force gold
-      # selection.
-      # gcc -- http://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Optimize-Options.html
-      "-fuse-ld=gold",
+        # Let clang find the ld.gold in the NDK.
+        ldflags += [ "--gcc-toolchain=$_rebased_android_toolchain_root" ]
+      }
 
-      # Experimentation found that using four linking threads
-      # saved ~20% of link time.
-      # https://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/281527606915bb36
-      # Only apply this to the target linker, since the host
-      # linker might not be gold, but isn't used much anyway.
-      # TODO(raymes): Disable threading because gold is frequently
-      # crashing on the bots: crbug.com/161942.
-      #"-Wl,--threads",
-      #"-Wl,--thread-count=4",
-    ]
+      # Use -mstackrealign due to a bug on ia32 Jelly Bean.
+      # See crbug.com/521527
+      if (current_cpu == "x86") {
+        cflags += [ "-mstackrealign" ]
+      }
+    } else {
+      ldflags += [
+        "-B$gold_path",
+        # Experimentation found that using four linking threads
+        # saved ~20% of link time.
+        # https://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/281527606915bb36
+        # Only apply this to the target linker, since the host
+        # linker might not be gold, but isn't used much anyway.
+        # TODO(raymes): Disable threading because gold is frequently
+        # crashing on the bots: crbug.com/161942.
+        #"-Wl,--threads",
+        #"-Wl,--thread-count=4",
+      ]
+    }
 
     if (gdb_index) {
       ldflags += [ "-Wl,--gdb-index" ]
@@ -336,15 +342,21 @@ config("compiler") {
     # Gold is the default linker for the bundled binutils so we explicitly
     # enable the bfd linker when use_gold is not set.
     ldflags += [ "-fuse-ld=bfd" ]
+  } else if (is_android && current_cpu == "mipsel" && is_clang) {
+    # Let clang find the ld.bfd in the NDK.
+    _rebased_android_toolchain_root =
+        rebase_path(android_toolchain_root, root_build_dir)
+    ldflags += [ "--gcc-toolchain=$rebased_android_toolchain_root" ]
   }
 
   if (is_posix && (use_gold || (use_lld && !is_nacl)) && !using_sanitizer &&
       !(is_android && use_order_profiling)) {
     # TODO(crbug.com/576197) - gcc on x86 platforms + gold + icf=all
     # doesn't currently work. Once it does, use icf=all everywhere.
+    # Additionally, on Android x86 --icf=safe seems to cause issues as well.
     if (is_clang || (target_cpu != "x86" && target_cpu != "x64")) {
       ldflags += [ "-Wl,--icf=all" ]
-    } else {
+    } else if (!is_android) {
       ldflags += [ "-Wl,--icf=safe" ]
     }
   }

config/compiler/compiler.gni

@@ -6,6 +6,7 @@ import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/toolchain/toolchain.gni")
 
 declare_args() {
   # How many symbols to include in the build. This affects the performance of
@@ -33,6 +34,15 @@ declare_args() {
   full_wpo_on_official = false
 }
 
+declare_args() {
+  # Whether to use the gold linker from binutils instead of lld or bfd.
+  use_gold = !use_lld &&
+             ((is_linux && (current_cpu == "x64" || current_cpu == "x86" ||
+                            current_cpu == "arm")) ||
+              (is_android && (current_cpu == "x86" || current_cpu == "x64" ||
+                              current_cpu == "arm")))
+}
+
 # If it wasn't manually set, set to an appropriate default.
 assert(symbol_level >= -1 && symbol_level <= 2, "Invalid symbol_level")
 if (symbol_level == -1) {

config/gcc/BUILD.gn

@@ -2,7 +2,9 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/compiler/compiler.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/config/sysroot.gni")
 import("//build/toolchain/toolchain.gni")
 
 # This config causes functions not to be automatically exported from shared
@@ -69,8 +71,9 @@ config("rpath_for_built_shared_libraries") {
 
 # Settings for executables.
 config("executable_ldconfig") {
+  ldflags = []
   if (is_android) {
-    ldflags = [
+    ldflags += [
       "-Bdynamic",
       "-Wl,-z,nocopyreloc",
     ]
@@ -80,19 +83,26 @@ config("executable_ldconfig") {
     if (is_component_build || using_sanitizer) {
       configs = [ ":rpath_for_built_shared_libraries" ]
     }
+    if (current_cpu == "mipsel") {
+      ldflags += [ "-pie" ]
+    }
+  }
 
+  if (!is_android || !use_gold) {
     # Find the path containing shared libraries for this toolchain
     # relative to the build directory. ${root_out_dir} will be a
     # subdirectory of ${root_build_dir} when cross compiling.
-    rebased_out_dir = rebase_path(root_out_dir, root_build_dir)
+    _rpath_link = rebase_path(root_out_dir, root_build_dir)
     if (shlib_subdir != ".") {
-      rpath_link = "${rebased_out_dir}/${shlib_subdir}"
-    } else {
-      rpath_link = rebased_out_dir
+      _rpath_link += "/$shlib_subdir"
+    }
+    if (is_android) {
+      _rebased_sysroot = rebase_path(sysroot, root_build_dir)
+      _rpath_link += ":$_rebased_sysroot/usr/lib"
     }
 
-    ldflags = [
-      "-Wl,-rpath-link=${rpath_link}",
+    ldflags += [
+      "-Wl,-rpath-link=$_rpath_link",
 
       # TODO(GYP): Do we need a check on the binutils version here?
       #
@@ -100,9 +110,6 @@ config("executable_ldconfig") {
       # and the new DT_RUNPATH doesn't work without --no-as-needed flag.
       "-Wl,--disable-new-dtags",
     ]
-    if (current_cpu == "mipsel") {
-      ldflags += [ "-pie" ]
-    }
   }
 }