Revert "[infra] Roll clang toolchain forward"

This reverts commit 8ee7a97651.

Reason for revert: lld optimization level -Wl,-O1 appears to either
have a regression or to confuse Golem binary comparison tool.

Original change's description:
> [infra] Roll clang toolchain forward
>
> Change-Id: I41afe48f2fdc056436b58dc8158c62e9207cc43f
> Reviewed-on: https://dart-review.googlesource.com/32140
> Commit-Queue: Zach Anderson <zra@google.com>
> Reviewed-by: Alexander Thomas <athom@google.com>

TBR=whesse@google.com,rmacnak@google.com,zra@google.com,athom@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I36ec03150a22f89c4cb5371dd1bf43df8a6f16f6
Reviewed-on: https://dart-review.googlesource.com/32800
Commit-Queue: Zach Anderson <zra@google.com>
Reviewed-by: Zach Anderson <zra@google.com>

DEPS

@@ -30,11 +30,9 @@ vars = {
 
   "co19_rev": "@dec2b67aaab3bb7339b9764049707e71e601da3d",
 
-  # As Flutter does, we pull buildtools, including the clang toolchain, from
-  # Fuchsia. This revision should be kept up to date with the revision pulled
-  # by the Flutter engine. If there are problems with the toolchain, contact
-  # fuchsia-toolchain@.
-  "buildtools_revision": "@de2d6da936fa0be8bcb0bacd096fe124efff2854",
+  # Revisions of GN related dependencies. This should match the revision
+  # pulled by Flutter.
+  "buildtools_revision": "@057ef89874e3c622248cf99259434fdc683c4e30",
 
   # Scripts that make 'git cl format' work.
   "clang_format_scripts_rev": "@c09c8deeac31f05bd801995c475e7c8070f9ecda",

build/config/compiler/BUILD.gn

@@ -341,9 +341,9 @@ config("compiler") {
   # define into the compile line.
   if (is_clang && (is_linux || is_mac)) {
     if (is_linux) {
-      toolchain_stamp_file = "//buildtools/linux64/clang.stamp"
+      toolchain_stamp_file = "//buildtools/linux64/toolchain.stamp"
     } else {
-      toolchain_stamp_file = "//buildtools/mac/clang.stamp"
+      toolchain_stamp_file = "//buildtools/mac/toolchain.stamp"
     }
     toolchain_version = read_file(toolchain_stamp_file, "trim string")
     defines = [ "TOOLCHAIN_VERSION=$toolchain_version" ]
@@ -503,10 +503,6 @@ if (is_win) {
     "-Wno-unused-parameter",  # Unused function parameters.
   ]
 
-  if (is_clang) {
-    default_warning_flags += [ "-Wno-tautological-constant-compare" ]
-  }
-
   if (is_mac) {
     # TODO(abarth): Re-enable once https://github.com/domokit/mojo/issues/728
     #               is fixed.

build/toolchain/android/BUILD.gn

@@ -46,8 +46,17 @@ template("android_gcc_toolchain") {
 
     is_clang = invoker.is_clang
     if (is_clang) {
-      prefix =
-          rebase_path("//buildtools/${host_os}-x64/clang/bin", root_build_dir)
+      host_suffix = ""
+      if (host_os == "linux") {
+        host_suffix = "x86_64-linux"
+      } else if (host_os == "mac") {
+        host_suffix = "x86_64-darwin"
+      } else {
+        assert(false, "Unknown host")
+      }
+
+      prefix = rebase_path("//buildtools/toolchain/clang+llvm-$host_suffix/bin",
+                           root_build_dir)
 
       cc = compiler_prefix + prefix + "/clang"
       cxx = compiler_prefix + prefix + "/clang++"

build/toolchain/gcc_toolchain.gni

@@ -40,9 +40,6 @@ concurrent_links = exec_script("get_concurrent_links.py", [], "value")
 #      Location of the strip executable. When specified, strip will be run on
 #      all executables as they are built. The stripped artifacts will be put in
 #      exe.stripped/.
-#  - llvm_objcopy
-#      Location of the llvm-objcopy executable. Used as strip instead of strip
-#      when specified.
 template("gcc_toolchain") {
   toolchain(target_name) {
     assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
@@ -196,7 +193,7 @@ template("gcc_toolchain") {
       outfile = "{{root_out_dir}}/$exename"
       rspfile = "$outfile.rsp"
 
-      if (defined(invoker.strip) || defined(invoker.llvm_objcopy)) {
+      if (defined(invoker.strip)) {
         stripped_outfile = "{{root_out_dir}}/exe.stripped/$exename"
       }
 
@@ -206,11 +203,6 @@ template("gcc_toolchain") {
         strip_command =
             "${strip} --strip-unneeded -o $stripped_outfile $outfile"
         command += " && " + strip_command
-      } else if (defined(invoker.llvm_objcopy)) {
-        strip = invoker.llvm_objcopy
-        strip_command =
-            "${strip} --strip-all $outfile $stripped_outfile"
-        command += " && " + strip_command
       }
       if (defined(invoker.postlink)) {
         command += " && " + invoker.postlink
@@ -220,7 +212,7 @@ template("gcc_toolchain") {
       outputs = [
         outfile,
       ]
-      if (defined(invoker.strip) || defined(invoker.llvm_objcopy)) {
+      if (defined(invoker.strip)) {
         outputs += [ stripped_outfile ]
       }
       if (defined(invoker.link_outputs)) {

build/toolchain/linux/BUILD.gn

@@ -46,12 +46,11 @@ gcc_toolchain("clang_arm") {
                        root_build_dir)
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
-
-  readelf = "${prefix}/llvm-readelf"
+  readelf = "readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
   ld = cxx
-  llvm_objcopy = "${prefix}/llvm-objcopy"
+  strip = "${prefix}/strip"
 
   toolchain_cpu = "arm"
   toolchain_os = "linux"
@@ -79,7 +78,8 @@ gcc_toolchain("arm64") {
 }
 
 gcc_toolchain("clang_arm64") {
-  prefix = rebase_path("//buildtools/linux-x64/clang/bin", root_build_dir)
+  prefix = rebase_path("//buildtools/toolchain/clang+llvm-x86_64-linux/bin",
+                       root_build_dir)
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
@@ -87,7 +87,7 @@ gcc_toolchain("clang_arm64") {
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
   ld = cxx
-  llvm_objcopy = "${prefix}/llvm-objcopy"
+  strip = "${prefix}/strip"
 
   toolchain_cpu = "arm64"
   toolchain_os = "linux"
@@ -95,15 +95,15 @@ gcc_toolchain("clang_arm64") {
 }
 
 gcc_toolchain("clang_x86") {
-  prefix = rebase_path("//buildtools/linux-x64/clang/bin", root_build_dir)
+  prefix = rebase_path("//buildtools/toolchain/clang+llvm-x86_64-linux/bin",
+                       root_build_dir)
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
-
-  readelf = "${prefix}/llvm-readelf"
+  readelf = "readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
   ld = cxx
-  llvm_objcopy = "${prefix}/llvm-objcopy"
+  strip = "${prefix}/strip"
 
   toolchain_cpu = "x86"
   toolchain_os = "linux"
@@ -127,15 +127,16 @@ gcc_toolchain("x86") {
 }
 
 gcc_toolchain("clang_x64") {
-  prefix = rebase_path("//buildtools/linux-x64/clang/bin", root_build_dir)
+  prefix = rebase_path("//buildtools/toolchain/clang+llvm-x86_64-linux/bin",
+                       root_build_dir)
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
-  readelf = "${prefix}/llvm-readelf"
+  readelf = "readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
   ld = cxx
-  llvm_objcopy = "${prefix}/llvm-objcopy"
+  strip = "${prefix}/strip"
 
   toolchain_cpu = "x64"
   toolchain_os = "linux"

build/toolchain/mac/BUILD.gn

@@ -222,7 +222,8 @@ template("mac_toolchain") {
 mac_toolchain("clang_x64") {
   toolchain_cpu = "x64"
   toolchain_os = "mac"
-  prefix = rebase_path("//buildtools/mac-x64/clang/bin", root_build_dir)
+  prefix = rebase_path("//buildtools/toolchain/clang+llvm-x86_64-darwin/bin",
+                       root_build_dir)
   cc = "${goma_prefix}$prefix/clang"
   cxx = "${goma_prefix}$prefix/clang++"
   ar = "${prefix}/llvm-ar"
@@ -236,7 +237,8 @@ mac_toolchain("clang_x64") {
 mac_toolchain("clang_x86") {
   toolchain_cpu = "i386"
   toolchain_os = "mac"
-  prefix = rebase_path("//buildtools/mac-x64/clang/bin", root_build_dir)
+  prefix = rebase_path("//buildtools/toolchain/clang+llvm-x86_64-darwin/bin",
+                       root_build_dir)
   cc = "${goma_prefix}$prefix/clang"
   cxx = "${goma_prefix}$prefix/clang++"
   ar = "${prefix}/llvm-ar"

tools/buildtools/update.py

@@ -14,6 +14,7 @@ THIS_DIR = os.path.abspath(os.path.dirname(__file__))
 DART_ROOT = os.path.abspath(os.path.join(THIS_DIR, '..', '..'))
 BUILDTOOLS = os.path.join(DART_ROOT, 'buildtools')
 TOOLS_BUILDTOOLS = os.path.join(DART_ROOT, 'tools', 'buildtools')
+TOOLCHAIN = os.path.join(BUILDTOOLS, 'toolchain')
 
 sys.path.insert(0, os.path.join(DART_ROOT, 'tools'))
 import find_depot_tools
@@ -23,7 +24,7 @@ DEPOT_PATH = find_depot_tools.add_depot_tools_to_path()
 
 def Update():
   path = os.path.join(BUILDTOOLS, 'update.sh')
-  command = ['/bin/bash', path, '--clang', '--gn']
+  command = ['/bin/bash', path, '--toolchain', '--gn']
   return subprocess.call(command, cwd=DART_ROOT)
 
 
@@ -73,19 +74,17 @@ def UpdateClangFormatOnWindows():
 def CopyClangFormat():
   if sys.platform == 'darwin':
     platform = 'darwin'
-    tools = 'mac'
-    toolchain = 'mac-x64'
+    subdir = 'mac'
   elif sys.platform.startswith('linux'):
     platform = 'linux'
-    tools = 'linux64'
-    toolchain = 'linux-x64'
+    subdir = 'linux64'
   else:
     print 'Unknown platform: ' + sys.platform
     return 1
 
   clang_format = os.path.join(
-      BUILDTOOLS, toolchain, 'clang', 'bin', 'clang-format')
-  dest = os.path.join(BUILDTOOLS, tools, 'clang-format')
+      TOOLCHAIN, 'clang+llvm-x86_64-' + platform, 'bin', 'clang-format')
+  dest = os.path.join(BUILDTOOLS, subdir, 'clang-format')
   shutil.copy2(clang_format, dest)
   return 0