[build] Update clang and gn to match Fuchsia.

This new version has functional TSAN.

Bug: dart-lang/sdk#39611
Change-Id: Ia9835fb6ad6de73f43faea695f893ed0c62fffa7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136380
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

Author: rmacnak-google

DEPS

@@ -47,8 +47,8 @@ vars = {
   # The list of revisions for these tools comes from Fuchsia, here:
   # https://fuchsia.googlesource.com/buildtools/+/master/fuchsia.ensure
   # If there are problems with the toolchain, contact fuchsia-toolchain@.
-  "clang_revision": "de39621f0f03f20633bdfa50bde97a3908bf6e98",
-  "gn_revision": "bdb0fd02324b120cacde634a9235405061c8ea06",
+  "clang_revision": "b25fc4123c77097c05ea221e023fa5c6a16e0f41",
+  "gn_revision": "239533d2d91a04b3317ca9101cf7189f4e651e4d",
 
   # Scripts that make 'git cl format' work.
   "clang_format_scripts_rev": "c09c8deeac31f05bd801995c475e7c8070f9ecda",
@@ -426,7 +426,7 @@ deps = {
   Var("dart_root") + "/buildtools/" + Var("host_os") + "-" + Var("host_cpu") + "/clang": {
       "packages": [
           {
-              "package": "fuchsia/clang/${{platform}}",
+              "package": "fuchsia/third_party/clang/${{platform}}",
               "version": "git_revision:" + Var("clang_revision"),
           },
       ],

build/config/clang/clang.gni

@@ -0,0 +1,10 @@
+# Copyright (c) 2020 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.
+
+default_clang_prefix =
+    rebase_path("//buildtools/${host_os}-${host_cpu}/clang/bin", root_build_dir)
+
+declare_args() {
+  clang_prefix = default_clang_prefix
+}

build/config/linux/BUILD.gn

@@ -8,19 +8,9 @@ config("sdk") {
   ldflags = []
   cflags = []
 
-  if (is_asan || is_lsan || is_msan || is_tsan || is_ubsan) {
-    ldflags += [ "-lrt" ]
-  } else if (is_clang) {
+  if (is_clang) {
     # Don't allow visible symbols from libc++ to be re-exported.
-    ldflags = [
-      "-nodefaultlibs",
-      "-lc++",
-      "-lc",
-      "-lm",
-      "-lpthread",
-      "-lclang_rt.builtins",
-      "-Wl,--exclude-libs=libc++.a",
-    ]
+    ldflags += [ "-Wl,--exclude-libs=libc++.a" ]
   }
 
   if (sysroot != "") {
@@ -47,7 +37,7 @@ config("sdk") {
   }
 
   if (is_qemu) {
-    cflags += ["-DDART_RUN_IN_QEMU_ARMv7"]
+    cflags += [ "-DDART_RUN_IN_QEMU_ARMv7" ]
   }
 }
 

build/config/mac/BUILD.gn

@@ -3,12 +3,16 @@
 # found in the LICENSE file.
 
 import("//build/config/sysroot.gni")
+import("../clang/clang.gni")
 
 config("sdk") {
   common_flags = [ "-stdlib=libc++" ]
 
   cflags = common_flags
-  ldflags = common_flags
+  ldflags = common_flags + [
+              "-nostdlib++",
+              "${clang_prefix}/../lib/libc++.a",
+            ]
 }
 
 # On Mac, this is used for everything except static libraries.

third_party/tcmalloc/BUILD.gn

@@ -35,7 +35,10 @@ config("internal_config") {
     "-faligned-new",
   ]
   if (is_clang) {
-    cflags += [ "-Wno-unused-const-variable" ]
+    cflags += [
+      "-Wno-unused-const-variable",
+      "-Wno-implicit-int-float-conversion",
+    ]
   }
   if (current_cpu == "arm" && !is_clang) {
     cflags += [ "-Wno-psabi" ]
@@ -80,9 +83,7 @@ source_set("tcmalloc") {
 
   public_configs = [ ":link_config" ]
 
-  deps = [
-    ":dynamic_annotations",
-  ]
+  deps = [ ":dynamic_annotations" ]
 
   include_dirs = [
     "include",

tools/bots/test_matrix.json

@@ -487,31 +487,31 @@
         "builder-tag": "analyzer_use_fasta"
       }
     },
-    "dartk-asan-(linux|mac|win)-(debug|product|release)-(ia32|x64)": {
+    "dartk-asan-(linux|mac)-(debug|product|release)-(ia32|x64)": {
       "options": {
         "builder-tag": "asan",
         "timeout": 240
       }
     },
-    "dartk-lsan-(linux|mac|win)-(debug|product|release)-(ia32|x64)": {
+    "dartk-lsan-(linux|mac)-(debug|product|release)-(ia32|x64)": {
       "options": {
         "builder-tag": "lsan",
         "timeout": 240
       }
     },
-    "dartk-msan-(linux|mac|win)-(debug|product|release)-(ia32|x64)": {
+    "dartk-msan-linux-(debug|product|release)-x64": {
       "options": {
         "builder-tag": "msan",
         "timeout": 240
       }
     },
-    "dartk-tsan-(linux|mac|win)-(debug|product|release)-x64": {
+    "dartk-tsan-(linux|mac)-(debug|product|release)-x64": {
       "options": {
         "builder-tag": "tsan",
         "timeout": 240
       }
     },
-    "dartk-ubsan-(linux|mac|win)-(debug|product|release)-(ia32|x64)": {
+    "dartk-ubsan-(linux|mac)-(debug|product|release)-(ia32|x64)": {
       "options": {
         "builder-tag": "ubsan",
         "timeout": 240
@@ -1446,7 +1446,6 @@
     },
     {
       "builders": [
-        "vm-kernel-msan-linux-release-ia32",
         "vm-kernel-msan-linux-release-x64"
       ],
       "meta": {