BASELINE: Update Chromium to 106.0.5249.126

Change-Id: Ib0bb21c437a7d1686e21c33f2d329f2ac425b7ab
Reviewed-on: https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/438936
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

19 files changed, 473 insertions, 537 deletions

diff --git a/chromium/tools/clang/blink_gc_plugin/CMakeLists.txt b/chromium/tools/clang/blink_gc_plugin/CMakeLists.txt
index 1ccb2ee6764..27ab135243a 100644
--- a/chromium/tools/clang/blink_gc_plugin/CMakeLists.txt
+++ b/chromium/tools/clang/blink_gc_plugin/CMakeLists.txt
@@ -31,6 +31,6 @@ endforeach()
 set_property(TARGET clang APPEND PROPERTY SOURCES ${absolute_sources})
 
 cr_add_test(blink_gc_plugin_test
-  python tests/test.py
+  python3 tests/test.py
   ${CMAKE_BINARY_DIR}/bin/clang
   )
diff --git a/chromium/tools/clang/blink_gc_plugin/process-graph.py b/chromium/tools/clang/blink_gc_plugin/process-graph.py
index eac8f363c64..c5976892a58 100755
--- a/chromium/tools/clang/blink_gc_plugin/process-graph.py
+++ b/chromium/tools/clang/blink_gc_plugin/process-graph.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # 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.
diff --git a/chromium/tools/clang/plugins/CMakeLists.txt b/chromium/tools/clang/plugins/CMakeLists.txt
index 0c79c004b19..63f5deed03d 100644
--- a/chromium/tools/clang/plugins/CMakeLists.txt
+++ b/chromium/tools/clang/plugins/CMakeLists.txt
@@ -23,6 +23,6 @@ endforeach()
 set_property(TARGET clang APPEND PROPERTY SOURCES ${absolute_sources})
 
 cr_add_test(plugins_test
-  python tests/test.py
+  python3 tests/test.py
   ${CMAKE_BINARY_DIR}/bin/clang
   )
diff --git a/chromium/tools/clang/plugins/FindBadConstructsAction.cpp b/chromium/tools/clang/plugins/FindBadConstructsAction.cpp
index f1618de6480..3ba4e6e69a1 100644
--- a/chromium/tools/clang/plugins/FindBadConstructsAction.cpp
+++ b/chromium/tools/clang/plugins/FindBadConstructsAction.cpp
@@ -53,12 +53,8 @@ bool FindBadConstructsAction::ParseArgs(const CompilerInstance& instance,
       options_.check_gmock_objects = true;
     } else if (args[i] == "check-layout-object-methods") {
       options_.check_layout_object_methods = true;
-    } else if (args[i] == "checked-ptr-as-trivial-member") {
-      options_.checked_ptr_as_trivial_member = true;
-    } else if (args[i] == "raw-ptr-template-as-trivial-member") {
-      options_.raw_ptr_template_as_trivial_member = true;
-    } else if (args[i] == "use-classify-type") {
-      // This option is ignored, will be removed soon.
+    } else if (args[i] == "raw-ref-template-as-trivial-member") {
+      options_.raw_ref_template_as_trivial_member = true;
     } else {
       parsed = false;
       llvm::errs() << "Unknown clang plugin argument: " << args[i] << "\n";
diff --git a/chromium/tools/clang/plugins/FindBadConstructsConsumer.cpp b/chromium/tools/clang/plugins/FindBadConstructsConsumer.cpp
index 0dadc5eb5fc..1f004360ff5 100644
--- a/chromium/tools/clang/plugins/FindBadConstructsConsumer.cpp
+++ b/chromium/tools/clang/plugins/FindBadConstructsConsumer.cpp
@@ -70,10 +70,8 @@ bool IsGmockObject(const CXXRecordDecl* decl) {
 }
 
 bool IsPodOrTemplateType(const CXXRecordDecl& record) {
-  return record.isPOD() ||
-         record.getDescribedClassTemplate() ||
-         record.getTemplateSpecializationKind() ||
-         record.isDependentType();
+  return record.isPOD() || record.getDescribedClassTemplate() ||
+         record.getTemplateSpecializationKind() || record.isDependentType();
 }
 
 // Use a local RAV implementation to simply collect all FunctionDecls marked for
@@ -226,13 +224,16 @@ void FindBadConstructsConsumer::Traverse(ASTContext& context) {
     layout_visitor_->VisitLayoutObjectMethods(context);
   }
   RecursiveASTVisitor::TraverseDecl(context.getTranslationUnitDecl());
-  if (ipc_visitor_) ipc_visitor_->set_context(nullptr);
+  if (ipc_visitor_)
+    ipc_visitor_->set_context(nullptr);
 }
 
 bool FindBadConstructsConsumer::TraverseDecl(Decl* decl) {
-  if (ipc_visitor_) ipc_visitor_->BeginDecl(decl);
+  if (ipc_visitor_)
+    ipc_visitor_->BeginDecl(decl);
   bool result = RecursiveASTVisitor::TraverseDecl(decl);
-  if (ipc_visitor_) ipc_visitor_->EndDecl();
+  if (ipc_visitor_)
+    ipc_visitor_->EndDecl();
   return result;
 }
 
@@ -249,12 +250,14 @@ bool FindBadConstructsConsumer::VisitTagDecl(clang::TagDecl* tag_decl) {
 
 bool FindBadConstructsConsumer::VisitTemplateSpecializationType(
     TemplateSpecializationType* spec) {
-  if (ipc_visitor_) ipc_visitor_->VisitTemplateSpecializationType(spec);
+  if (ipc_visitor_)
+    ipc_visitor_->VisitTemplateSpecializationType(spec);
   return true;
 }
 
 bool FindBadConstructsConsumer::VisitCallExpr(CallExpr* call_expr) {
-  if (ipc_visitor_) ipc_visitor_->VisitCallExpr(call_expr);
+  if (ipc_visitor_)
+    ipc_visitor_->VisitCallExpr(call_expr);
   return true;
 }
 
@@ -369,8 +372,7 @@ void FindBadConstructsConsumer::CheckCtorDtorWeight(
   // destructor can be inlined.
   int templated_base_classes = 0;
   for (CXXRecordDecl::base_class_const_iterator it = record->bases_begin();
-       it != record->bases_end();
-       ++it) {
+       it != record->bases_end(); ++it) {
     if (it->getTypeSourceInfo()->getTypeLoc().getTypeLocClass() ==
         TypeLoc::TemplateSpecialization) {
       ++templated_base_classes;
@@ -382,8 +384,7 @@ void FindBadConstructsConsumer::CheckCtorDtorWeight(
   int non_trivial_member = 0;
   int templated_non_trivial_member = 0;
   for (RecordDecl::field_iterator it = record->field_begin();
-       it != record->field_end();
-       ++it) {
+       it != record->field_end(); ++it) {
     switch (ClassifyType(it->getType().getTypePtr())) {
       case TypeClassification::kTrivial:
         trivial_member += 1;
@@ -429,8 +430,7 @@ void FindBadConstructsConsumer::CheckCtorDtorWeight(
       // Iterate across all the constructors in this file and yell if we
       // find one that tries to be inline.
       for (CXXRecordDecl::ctor_iterator it = record->ctor_begin();
-           it != record->ctor_end();
-           ++it) {
+           it != record->ctor_end(); ++it) {
         // The current check is buggy. An implicit copy constructor does not
         // have an inline body, so this check never fires for classes with a
         // user-declared out-of-line constructor.
@@ -462,8 +462,9 @@ void FindBadConstructsConsumer::CheckCtorDtorWeight(
                                             diag_inline_complex_ctor_);
           }
         } else if (it->isInlined() && !it->isInlineSpecified() &&
-                   !it->isDeleted() && (!it->isCopyOrMoveConstructor() ||
-                                        it->isExplicitlyDefaulted())) {
+                   !it->isDeleted() &&
+                   (!it->isCopyOrMoveConstructor() ||
+                    it->isExplicitlyDefaulted())) {
           // isInlined() is a more reliable check than hasInlineBody(), but
           // unfortunately, it results in warnings for implicit copy/move
           // constructors in the previously mentioned situation. To preserve
@@ -528,8 +529,7 @@ void FindBadConstructsConsumer::CheckVirtualMethods(
   }
 
   for (CXXRecordDecl::method_iterator it = record->method_begin();
-       it != record->method_end();
-       ++it) {
+       it != record->method_end(); ++it) {
     if (it->isCopyAssignmentOperator() || isa<CXXConstructorDecl>(*it)) {
       // Ignore constructors and assignment operators.
     } else if (isa<CXXDestructorDecl>(*it) &&
@@ -708,13 +708,16 @@ FindBadConstructsConsumer::ClassifyType(const Type* type) {
       if (name == "std::basic_string")
         return TypeClassification::kNonTrivialExternTemplate;
 
-      // `base::raw_ptr` is non-trivial if the `use_backup_ref_ptr` flag is
-      // enabled, and trivial otherwise. Since there are many existing types
-      // using this that we don't wish to burden with defining custom
-      // ctors/dtors, and we'd rather not vary on triviality by build config,
-      // treat this as always trivial.
-      if (name == "base::raw_ptr")
+      // `base::raw_ptr` and `base::raw_ref` are non-trivial if the
+      // `use_backup_ref_ptr` flag is enabled, and trivial otherwise. Since
+      // there are many existing types using this that we don't wish to burden
+      // with defining custom ctors/dtors, and we'd rather not vary on
+      // triviality by build config, treat this as always trivial.
+      if (name == "base::raw_ptr" ||
+          (options_.raw_ref_template_as_trivial_member &&
+           name == "base::raw_ref")) {
         return TypeClassification::kTrivialTemplate;
+      }
 
       return TypeClassification::kNonTrivial;
     }
@@ -837,9 +840,8 @@ FindBadConstructsConsumer::CheckRecordForRefcountIssue(
 
 // Returns true if |base| specifies one of the Chromium reference counted
 // classes (base::RefCounted / base::RefCountedThreadSafe).
-bool FindBadConstructsConsumer::IsRefCounted(
-    const CXXBaseSpecifier* base,
-    CXXBasePath& path) {
+bool FindBadConstructsConsumer::IsRefCounted(const CXXBaseSpecifier* base,
+                                             CXXBasePath& path) {
   const TemplateSpecializationType* base_type =
       dyn_cast<TemplateSpecializationType>(
           UnwrapType(base->getType().getTypePtr()));
@@ -990,8 +992,7 @@ void FindBadConstructsConsumer::CheckRefCountedDtors(
   }
 
   for (CXXBasePaths::const_paths_iterator it = dtor_paths.begin();
-       it != dtor_paths.end();
-       ++it) {
+       it != dtor_paths.end(); ++it) {
     // The record with the problem will always be the last record
     // in the path, since it is the record that stopped the search.
     const CXXRecordDecl* problem_record = dyn_cast<CXXRecordDecl>(
diff --git a/chromium/tools/clang/plugins/Options.h b/chromium/tools/clang/plugins/Options.h
index e3e29e14742..78fd7fb9d05 100644
--- a/chromium/tools/clang/plugins/Options.h
+++ b/chromium/tools/clang/plugins/Options.h
@@ -12,8 +12,7 @@ struct Options {
   bool check_ipc = false;
   bool check_gmock_objects = false;
   bool check_layout_object_methods = false;
-  bool checked_ptr_as_trivial_member = false;
-  bool raw_ptr_template_as_trivial_member = false;
+  bool raw_ref_template_as_trivial_member = false;
 };
 
 }  // namespace chrome_checker
diff --git a/chromium/tools/clang/pylib/clang/compile_db_test.py b/chromium/tools/clang/pylib/clang/compile_db_test.py
index 06b7e43ef8e..2ae494236c6 100755
--- a/chromium/tools/clang/pylib/clang/compile_db_test.py
+++ b/chromium/tools/clang/pylib/clang/compile_db_test.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env vpython
+#!/usr/bin/env vpython3
 # Copyright 2019 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.
diff --git a/chromium/tools/clang/rewrite_raw_ptr_fields/RewriteRawPtrFields.cpp b/chromium/tools/clang/rewrite_raw_ptr_fields/RewriteRawPtrFields.cpp
index c7e2d9662d8..b854538dbe7 100644
--- a/chromium/tools/clang/rewrite_raw_ptr_fields/RewriteRawPtrFields.cpp
+++ b/chromium/tools/clang/rewrite_raw_ptr_fields/RewriteRawPtrFields.cpp
@@ -852,6 +852,14 @@ class FieldDeclRewriter : public MatchFinder::MatchCallback {
 
     const clang::TypeSourceInfo* type_source_info =
         field_decl->getTypeSourceInfo();
+    if (auto* ivar_decl = clang::dyn_cast<clang::ObjCIvarDecl>(field_decl)) {
+      // Objective-C @synthesize statements should not be rewritten. They return
+      // null for getTypeSourceInfo().
+      if (ivar_decl->getSynthesize()) {
+        assert(!type_source_info);
+        return;
+      }
+    }
     assert(type_source_info && "assuming |type_source_info| is always present");
 
     clang::QualType pointer_type = type_source_info->getType();
diff --git a/chromium/tools/clang/rewrite_raw_ptr_fields/manual-fields-to-ignore.txt b/chromium/tools/clang/rewrite_raw_ptr_fields/manual-fields-to-ignore.txt
index 1a88fb4b414..71549e3c53f 100644
--- a/chromium/tools/clang/rewrite_raw_ptr_fields/manual-fields-to-ignore.txt
+++ b/chromium/tools/clang/rewrite_raw_ptr_fields/manual-fields-to-ignore.txt
@@ -67,6 +67,7 @@ views::LayoutManager::view_setting_visibility_on_
 FullscreenController::deactivated_contents_
 content::RenderWidgetHostInputEventRouter::touch_target_
 content::RenderWidgetHostInputEventRouter::touchpad_gesture_target_
+base::MessagePumpLibevent::run_state_
 
 # Populated manually - incompatibilities with tracing in not-rewritten platform specific code
 TabStripModelChange::RemovedTab::contents
@@ -235,6 +236,36 @@ device::(anonymous namespace)::CBORExtract_RequiredInOptionalMap_Test::TestBody(
 # Populated manually - pointer to Objective-C object
 gfx::ScopedNSGraphicsContextSaveGState::context_
 base::mac::ScopedNSAutoreleasePool::autorelease_pool_
+content::ThemeHelperMac::theme_observer_
+content::PopupMenuHelper::menu_runner_
+content::ShellJavaScriptDialog::helper_
+ui::ClipboardFormatType::data_
+ui::WeakPtrNSObjectFactory::handle_
+content::NativeEventProcessorObserver::event_
+image_editor::EventCaptureMac::web_contents_view_
+image_editor::EventCaptureMac::window_
+content::ScopedNotifyNativeEventProcessorObserver::event_
+device::fido::mac::TouchIdCredentialStore::authentication_context_
+
+# Populated manually - struct is part of separate binary and must be a POD
+# https://source.chromium.org/chromium/chromium/src/+/main:chrome/common/mac/app_mode_common.mm;l=64
+app_mode::ChromeAppModeInfo::argv
+
+# Populated manually - requires @property rewrite
+# In Objective-C the instance variable type and property type must be the same.
+# Currently, the rewriter can only rewrite the instance variable declaration.
+# So the types do not match, and causes a compiler error.
+# These fields can be rewritten once the rewriter can rewrite @property declarations.
+ObjCPropertyTestBase::_basePointer
+ObjCPropertyTestDerived::_derivedPointer
+ObjCPropertyTestDerived::_protoPointer
+NativeWidgetMacNSWindow::_bridge
+AlertBridgeHelper::_alertBridge
+BridgedContentView::_bridge
+WindowControlsOverlayNSView::_bridge
+AXPlatformNodeCocoa::_node
+ShellNativeAppWindowController::_appWindow
+WatchedLifetimeMenuController::_deallocCalled
 
 #######
 # BackupRefPtr-specific sections
@@ -309,6 +340,11 @@ disk_cache::MappedFile::buffer_
 network::MojoToNetPendingBuffer::buffer_
 network::NetToMojoPendingBuffer::buffer_
 
+# Populated manually - Field initialized with non-nullptr value in constexpr.
+enterprise_connectors::ServiceProvider::analysis
+enterprise_connectors::ServiceProvider::reporting
+enterprise_connectors::ServiceProvider::file_system
+
 # Populated manually - based on sampling profiler data and tab_search:top100:2020 profiler data
 (anonymous namespace)::TlsVectorEntry::data
 LinkNodeBase::next_
diff --git a/chromium/tools/clang/rewrite_raw_ptr_fields/manual-paths-to-ignore.txt b/chromium/tools/clang/rewrite_raw_ptr_fields/manual-paths-to-ignore.txt
index 0a7941f3f14..df0e1d1b79b 100644
--- a/chromium/tools/clang/rewrite_raw_ptr_fields/manual-paths-to-ignore.txt
+++ b/chromium/tools/clang/rewrite_raw_ptr_fields/manual-paths-to-ignore.txt
@@ -23,6 +23,7 @@ base/allocator/
 # TODO(bartekn): Update the list of dependencies.
 base/logging.h
 base/synchronization/lock_impl.h
+base/check.h
 
 # Exclude - deprecated and contains legacy C++ and pre-C++11 code.
 ppapi/
diff --git a/chromium/tools/clang/rewrite_raw_ptr_fields/rewrite-multiple-platforms.sh b/chromium/tools/clang/rewrite_raw_ptr_fields/rewrite-multiple-platforms.sh
index 7d809473f5f..9f22361fb40 100755
--- a/chromium/tools/clang/rewrite_raw_ptr_fields/rewrite-multiple-platforms.sh
+++ b/chromium/tools/clang/rewrite_raw_ptr_fields/rewrite-multiple-platforms.sh
@@ -70,6 +70,31 @@ chrome_pgo_phase = 0
 EOF
         ;;
 
+    linux)
+        cat <<EOF
+target_os = "linux"
+dcheck_always_on = true
+is_chrome_branded = true
+is_debug = false
+is_official_build = true
+use_goma = false
+chrome_pgo_phase = 0
+EOF
+        ;;
+
+    cros)
+        cat <<EOF
+target_os = "chromeos"
+chromeos_is_browser_only = true
+dcheck_always_on = true
+is_chrome_branded = true
+is_debug = false
+is_official_build = true
+use_goma = false
+chrome_pgo_phase = 0
+EOF
+        ;;
+
     mac)
         cat <<EOF
 target_os = "mac"
diff --git a/chromium/tools/clang/scripts/build.py b/chromium/tools/clang/scripts/build.py
index 9313a10005f..970f53cfc14 100755
--- a/chromium/tools/clang/scripts/build.py
+++ b/chromium/tools/clang/scripts/build.py
@@ -27,7 +27,8 @@ import tempfile
 
 from update import (CDS_URL, CHROMIUM_DIR, CLANG_REVISION, LLVM_BUILD_DIR,
                     FORCE_HEAD_REVISION_FILE, PACKAGE_VERSION, RELEASE_VERSION,
-                    STAMP_FILE, DownloadUrl, DownloadAndUnpack, EnsureDirExists,
+                    STAMP_FILE, THIS_DIR, DownloadUrl, DownloadAndUnpack,
+                    DownloadAndUnpackPackage, EnsureDirExists, GetDefaultHostOs,
                     ReadStampFile, RmTree, WriteStampFile)
 
 # Path constants. (All of these should be absolute paths.)
@@ -147,7 +148,10 @@ def CheckoutLLVM(commit, dir):
     print('Removing %s.' % dir)
     RmTree(dir)
 
-  clone_cmd = ['git', 'clone', 'https://github.com/llvm/llvm-project/', dir]
+  clone_cmd = [
+      'git', 'clone', 'https://chromium.googlesource.com/external/' +
+      'github.com/llvm/llvm-project', dir
+  ]
 
   if RunCommand(clone_cmd, fail_hard=False):
     os.chdir(dir)
@@ -166,11 +170,11 @@ def UrlOpen(url):
 
 def GetLatestLLVMCommit():
   """Get the latest commit hash in the LLVM monorepo."""
-  ref = json.loads(
-      UrlOpen(('https://api.github.com/repos/'
-               'llvm/llvm-project/git/refs/heads/main')))
-  assert ref['object']['type'] == 'commit'
-  return ref['object']['sha']
+  main = json.loads(
+      UrlOpen('https://chromium.googlesource.com/external/' +
+              'github.com/llvm/llvm-project/' +
+              '+/refs/heads/main?format=JSON').replace(")]}'", ""))
+  return main['commit']
 
 
 def GetCommitDescription(commit):
@@ -183,14 +187,6 @@ def GetCommitDescription(commit):
       universal_newlines=True).rstrip()
 
 
-def DeleteChromeToolsShim():
-  # TODO: These dirs are no longer used. Remove this code after a while.
-  OLD_SHIM_DIR = os.path.join(LLVM_DIR, 'tools', 'zzz-chrometools')
-  shutil.rmtree(OLD_SHIM_DIR, ignore_errors=True)
-  CHROME_TOOLS_SHIM_DIR = os.path.join(LLVM_DIR, 'llvm', 'tools', 'chrometools')
-  shutil.rmtree(CHROME_TOOLS_SHIM_DIR, ignore_errors=True)
-
-
 def AddCMakeToPath(args):
   """Download CMake and add it to PATH."""
   if args.use_system_cmake:
@@ -389,22 +385,9 @@ def DownloadRPMalloc():
 
 
 def DownloadPinnedClang():
-  # The update.py in this current revision may have a patched revision while
-  # building new clang packages. Get update.py off HEAD~ to pull the current
-  # pinned clang.
-  if not os.path.exists(PINNED_CLANG_DIR):
-    os.mkdir(os.path.join(PINNED_CLANG_DIR))
-
-  script_path = os.path.join(PINNED_CLANG_DIR, 'update.py')
-
-  with open(script_path, 'w') as f:
-    subprocess.check_call(
-        ['git', 'show', 'HEAD~:tools/clang/scripts/update.py'],
-        stdout=f,
-        cwd=CHROMIUM_DIR)
-  print("Running pinned update.py")
-  subprocess.check_call(
-      [sys.executable, script_path, '--output-dir=' + PINNED_CLANG_DIR])
+  PINNED_CLANG_VERSION = 'llvmorg-16-init-572-gdde41c6c-3'
+  DownloadAndUnpackPackage('clang', PINNED_CLANG_DIR, GetDefaultHostOs(),
+                           PINNED_CLANG_VERSION)
 
 
 # TODO(crbug.com/929645): Remove once we don't need gcc's libstdc++.
@@ -414,8 +397,8 @@ def MaybeDownloadHostGcc(args):
   if args.gcc_toolchain:
     return
   gcc_dir = os.path.join(LLVM_BUILD_TOOLS_DIR, 'gcc-10.2.0-bionic')
-  if os.path.isdir(gcc_dir):  # TODO(thakis): Remove this branch after a few weeks.
-    RmTree(gcc_dir)
+  if os.path.isdir(gcc_dir):
+    RmTree(gcc_dir)  # TODO(thakis): Remove this branch after a few weeks.
   if not os.path.exists(gcc_dir):
     DownloadAndUnpack(CDS_URL + '/tools/gcc-10.2.0-bionic.tgz', gcc_dir)
   args.gcc_toolchain = gcc_dir
@@ -476,6 +459,28 @@ def CopyLibstdcpp(args, build_dir):
   CopyFile(libstdcpp, os.path.join(build_dir, 'lib'))
 
 
+def compiler_rt_cmake_flags(*, sanitizers, profile):
+  # Don't set -DCOMPILER_RT_BUILD_BUILTINS=ON/OFF as it interferes with the
+  # runtimes logic of building builtins.
+  args = [
+      # Build crtbegin/crtend. It's just two tiny TUs, so just enable this
+      # everywhere, even though we only need it on Linux.
+      'COMPILER_RT_BUILD_CRT=ON',
+      'COMPILER_RT_BUILD_LIBFUZZER=OFF',
+      'COMPILER_RT_BUILD_MEMPROF=OFF',
+      'COMPILER_RT_BUILD_ORC=OFF',
+      'COMPILER_RT_BUILD_PROFILE=' + ('ON' if profile else 'OFF'),
+      'COMPILER_RT_BUILD_SANITIZERS=' + ('ON' if sanitizers else 'OFF'),
+      'COMPILER_RT_BUILD_XRAY=OFF',
+      # See crbug.com/1205046: don't build scudo (and others we don't need).
+      'COMPILER_RT_SANITIZERS_TO_BUILD=asan;dfsan;msan;hwasan;tsan;cfi',
+      # We explicitly list all targets we want to build, do not autodetect
+      # targets.
+      'COMPILER_RT_DEFAULT_TARGET_ONLY=ON',
+  ]
+  return args
+
+
 def gn_arg(v):
   if v == 'True':
     return True
@@ -590,9 +595,6 @@ def main():
   # move this down to where we fetch other build tools.
   AddGnuWinToPath()
 
-  if sys.platform == 'darwin':
-    isysroot = subprocess.check_output(['xcrun', '--show-sdk-path'],
-                                       universal_newlines=True).rstrip()
 
   if args.build_dir:
     LLVM_BUILD_DIR = args.build_dir
@@ -614,7 +616,6 @@ def main():
   WriteStampFile('', FORCE_HEAD_REVISION_FILE)
 
   AddCMakeToPath(args)
-  DeleteChromeToolsShim()
 
 
   if args.skip_build:
@@ -633,18 +634,15 @@ def main():
 
   targets = 'AArch64;ARM;Mips;PowerPC;RISCV;SystemZ;WebAssembly;X86'
 
-  projects = 'clang;compiler-rt;lld;clang-tools-extra'
-
-  if sys.platform == 'darwin':
-    # clang needs libc++, else -stdlib=libc++ won't find includes
-    # (this is needed for bootstrap builds and for building the fuchsia runtime)
-    projects += ';libcxx'
+  projects = 'clang;lld;clang-tools-extra'
+  runtimes = 'compiler-rt'
 
   base_cmake_args = [
       '-GNinja',
       '-DCMAKE_BUILD_TYPE=Release',
       '-DLLVM_ENABLE_ASSERTIONS=%s' % ('OFF' if args.disable_asserts else 'ON'),
       '-DLLVM_ENABLE_PROJECTS=' + projects,
+      '-DLLVM_ENABLE_RUNTIMES=' + runtimes,
       '-DLLVM_TARGETS_TO_BUILD=' + targets,
       # PIC needed for Rust build (links LLVM into shared object)
       '-DLLVM_ENABLE_PIC=ON',
@@ -657,12 +655,8 @@ def main():
       '-DBUG_REPORT_URL=' + BUG_REPORT_URL,
       # Don't run Go bindings tests; PGO makes them confused.
       '-DLLVM_INCLUDE_GO_TESTS=OFF',
-      # TODO(crbug.com/1113475): Update binutils.
-      '-DENABLE_X86_RELAX_RELOCATIONS=NO',
       # See crbug.com/1126219: Use native symbolizer instead of DIA
       '-DLLVM_ENABLE_DIA_SDK=OFF',
-      # See crbug.com/1205046: don't build scudo (and others we don't need).
-      '-DCOMPILER_RT_SANITIZERS_TO_BUILD=asan;dfsan;msan;hwasan;tsan;cfi',
       # The default value differs per platform, force it off everywhere.
       '-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF',
       # Don't use curl.
@@ -670,6 +664,20 @@ def main():
       # Build libclang.a as well as libclang.so
       '-DLIBCLANG_BUILD_STATIC=ON',
   ]
+
+  if sys.platform == 'darwin':
+    isysroot = subprocess.check_output(['xcrun', '--show-sdk-path'],
+                                       universal_newlines=True).rstrip()
+
+  # See https://crbug.com/1302636#c49 - #c56 -- intercepting crypt_r() does not
+  # work with the sysroot for not fully understood reasons. Disable it.
+  sanitizers_override = [
+    '-DSANITIZER_OVERRIDE_INTERCEPTORS',
+    '-I' + os.path.join(THIS_DIR, 'sanitizers'),
+  ]
+  cflags += sanitizers_override
+  cxxflags += sanitizers_override
+
   if args.host_cc or args.host_cxx:
     assert args.host_cc and args.host_cxx, \
            "--host-cc and --host-cxx need to be used together"
@@ -690,38 +698,65 @@ def main():
       cc = os.path.join(PINNED_CLANG_DIR, 'bin', 'clang')
       cxx = os.path.join(PINNED_CLANG_DIR, 'bin', 'clang++')
 
-    if sys.platform != 'darwin':
-      # The host clang has lld, but self-hosting with lld is still slightly
-      # broken on mac.
-      # TODO: check if this works now.
-      base_cmake_args.append('-DLLVM_ENABLE_LLD=ON')
-
     if sys.platform.startswith('linux'):
       MaybeDownloadHostGcc(args)
-      # Use the libraries in the specified gcc installation for building.
-      cflags.append('--gcc-toolchain=' + args.gcc_toolchain)
-      cxxflags.append('--gcc-toolchain=' + args.gcc_toolchain)
-      base_cmake_args += [
-          '-DLLVM_STATIC_LINK_CXX_STDLIB=ON',
-          # Force compiler-rt tests to use our gcc toolchain
-          # because the one on the host may be too old.
-          # Even with -static-libstdc++ the compiler-rt tests add -lstdc++
-          # which adds a DT_NEEDED to libstdc++.so so we need to add RPATHs
-          # to the gcc toolchain.
-          '-DCOMPILER_RT_TEST_COMPILER_CFLAGS=--gcc-toolchain=' +
-          args.gcc_toolchain + ' -Wl,-rpath,' +
-          os.path.join(args.gcc_toolchain, 'lib64') + ' -Wl,-rpath,' +
-          os.path.join(args.gcc_toolchain, 'lib32')
-      ]
-
-  if sys.platform == 'darwin':
-    # For libc++, we only want the headers.
-    base_cmake_args.extend([
-        '-DLIBCXX_ENABLE_SHARED=OFF',
-        '-DLIBCXX_ENABLE_STATIC=OFF',
-        '-DLIBCXX_INCLUDE_TESTS=OFF',
-        '-DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=OFF',
-    ])
+      base_cmake_args += [ '-DLLVM_STATIC_LINK_CXX_STDLIB=ON' ]
+
+  if sys.platform != 'darwin':
+    # The host clang has lld, but self-hosting with lld is still slightly
+    # broken on mac.
+    # TODO: check if this works now.
+    base_cmake_args.append('-DLLVM_ENABLE_LLD=ON')
+
+  if sys.platform.startswith('linux'):
+    # Download sysroots. This uses basically Chromium's sysroots, but with
+    # minor changes:
+    # - glibc version bumped to 2.18 to make __cxa_thread_atexit_impl
+    #   work (clang can require 2.18; chromium currently doesn't)
+    # - libcrypt.so.1 reversioned so that crypt() is picked up from glibc
+    # The sysroot was built at
+    # https://chromium-review.googlesource.com/c/chromium/src/+/3684954/1
+    # and the hashes here are from sysroots.json in that CL.
+    toolchain_bucket = 'https://commondatastorage.googleapis.com/chrome-linux-sysroot/toolchain/'
+
+    # amd64
+    # hash from https://chromium-review.googlesource.com/c/chromium/src/+/3684954/1/build/linux/sysroot_scripts/sysroots.json#3
+    toolchain_hash = '2028cdaf24259d23adcff95393b8cc4f0eef714b'
+    toolchain_name = 'debian_bullseye_amd64_sysroot'
+    U = toolchain_bucket + toolchain_hash + '/' + toolchain_name + '.tar.xz'
+    sysroot_amd64 = os.path.join(LLVM_BUILD_TOOLS_DIR, toolchain_name)
+    DownloadAndUnpack(U, sysroot_amd64)
+
+    # i386
+    # hash from https://chromium-review.googlesource.com/c/chromium/src/+/3684954/1/build/linux/sysroot_scripts/sysroots.json#23
+    toolchain_hash = 'a033618b5e092c86e96d62d3c43f7363df6cebe7'
+    toolchain_name = 'debian_bullseye_i386_sysroot'
+    U = toolchain_bucket + toolchain_hash + '/' + toolchain_name + '.tar.xz'
+    sysroot_i386 = os.path.join(LLVM_BUILD_TOOLS_DIR, toolchain_name)
+    DownloadAndUnpack(U, sysroot_i386)
+
+    # arm
+    # hash from https://chromium-review.googlesource.com/c/chromium/src/+/3684954/1/build/linux/sysroot_scripts/sysroots.json#8
+    toolchain_hash = '0b9a3c54d2d5f6b1a428369aaa8d7ba7b227f701'
+    toolchain_name = 'debian_bullseye_arm_sysroot'
+    U = toolchain_bucket + toolchain_hash + '/' + toolchain_name + '.tar.xz'
+    sysroot_arm = os.path.join(LLVM_BUILD_TOOLS_DIR, toolchain_name)
+    DownloadAndUnpack(U, sysroot_arm)
+
+    # arm64
+    # hash from https://chromium-review.googlesource.com/c/chromium/src/+/3684954/1/build/linux/sysroot_scripts/sysroots.json#12
+    toolchain_hash = '0e28d9832614729bb5b731161ff96cb4d516f345'
+    toolchain_name = 'debian_bullseye_arm64_sysroot'
+    U = toolchain_bucket + toolchain_hash + '/' + toolchain_name + '.tar.xz'
+    sysroot_arm64 = os.path.join(LLVM_BUILD_TOOLS_DIR, toolchain_name)
+    DownloadAndUnpack(U, sysroot_arm64)
+
+    # Add the sysroot to base_cmake_args.
+    if platform.machine() == 'aarch64':
+      base_cmake_args.append('-DCMAKE_SYSROOT=' + sysroot_arm64)
+    else:
+      # amd64 is the default toolchain.
+      base_cmake_args.append('-DCMAKE_SYSROOT=' + sysroot_amd64)
 
   if sys.platform == 'win32':
     base_cmake_args.append('-DLLVM_USE_CRT_RELEASE=MT')
@@ -752,14 +787,16 @@ def main():
     os.chdir(LLVM_BOOTSTRAP_DIR)
 
     projects = 'clang'
-    if args.pgo:
-      # Need libclang_rt.profile
-      projects += ';compiler-rt'
+    runtimes = ''
+    if args.pgo or sys.platform == 'darwin':
+      # Need libclang_rt.profile for PGO.
+      # On macOS, the bootstrap toolchain needs to have compiler-rt because
+      # dsymutil's link needs libclang_rt.osx.a. Only the x86_64 osx
+      # libraries are needed though, and only libclang_rt (i.e.
+      # COMPILER_RT_BUILD_BUILTINS).
+      runtimes += ';compiler-rt'
     if sys.platform != 'darwin':
       projects += ';lld'
-    if sys.platform == 'darwin':
-      # Need libc++ and compiler-rt for the bootstrap compiler on mac.
-      projects += ';libcxx;compiler-rt'
 
     bootstrap_targets = 'X86'
     if sys.platform == 'darwin':
@@ -768,6 +805,7 @@ def main():
     bootstrap_args = base_cmake_args + [
         '-DLLVM_TARGETS_TO_BUILD=' + bootstrap_targets,
         '-DLLVM_ENABLE_PROJECTS=' + projects,
+        '-DLLVM_ENABLE_RUNTIMES=' + runtimes,
         '-DCMAKE_INSTALL_PREFIX=' + LLVM_BOOTSTRAP_INSTALL_DIR,
         '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
         '-DCMAKE_CXX_FLAGS=' + ' '.join(cxxflags),
@@ -777,19 +815,13 @@ def main():
         # Ignore args.disable_asserts for the bootstrap compiler.
         '-DLLVM_ENABLE_ASSERTIONS=ON',
     ]
+    # PGO needs libclang_rt.profile but none of the other compiler-rt stuff.
+    bootstrap_args.extend([
+        '-D' + f
+        for f in compiler_rt_cmake_flags(sanitizers=False, profile=args.pgo)
+    ])
     if sys.platform == 'darwin':
-      # On macOS, the bootstrap toolchain needs to have compiler-rt because
-      # dsymutil's link needs libclang_rt.osx.a. Only the x86_64 osx
-      # libraries are needed though, and only libclang_rt (i.e.
-      # COMPILER_RT_BUILD_BUILTINS).
       bootstrap_args.extend([
-          '-DCOMPILER_RT_BUILD_BUILTINS=ON',
-          '-DCOMPILER_RT_BUILD_CRT=OFF',
-          '-DCOMPILER_RT_BUILD_LIBFUZZER=OFF',
-          '-DCOMPILER_RT_BUILD_MEMPROF=OFF',
-          '-DCOMPILER_RT_BUILD_ORC=OFF',
-          '-DCOMPILER_RT_BUILD_SANITIZERS=OFF',
-          '-DCOMPILER_RT_BUILD_XRAY=OFF',
           '-DCOMPILER_RT_ENABLE_IOS=OFF',
           '-DCOMPILER_RT_ENABLE_WATCHOS=OFF',
           '-DCOMPILER_RT_ENABLE_TVOS=OFF',
@@ -798,18 +830,6 @@ def main():
         bootstrap_args.extend(['-DDARWIN_osx_ARCHS=arm64'])
       else:
         bootstrap_args.extend(['-DDARWIN_osx_ARCHS=x86_64'])
-    elif args.pgo:
-      # PGO needs libclang_rt.profile but none of the other compiler-rt stuff.
-      bootstrap_args.extend([
-          '-DCOMPILER_RT_BUILD_BUILTINS=OFF',
-          '-DCOMPILER_RT_BUILD_CRT=OFF',
-          '-DCOMPILER_RT_BUILD_LIBFUZZER=OFF',
-          '-DCOMPILER_RT_BUILD_MEMPROF=OFF',
-          '-DCOMPILER_RT_BUILD_ORC=OFF',
-          '-DCOMPILER_RT_BUILD_PROFILE=ON',
-          '-DCOMPILER_RT_BUILD_SANITIZERS=OFF',
-          '-DCOMPILER_RT_BUILD_XRAY=OFF',
-          ])
 
     if cc is not None:  bootstrap_args.append('-DCMAKE_C_COMPILER=' + cc)
     if cxx is not None: bootstrap_args.append('-DCMAKE_CXX_COMPILER=' + cxx)
@@ -844,8 +864,6 @@ def main():
     os.chdir(LLVM_INSTRUMENTED_DIR)
 
     projects = 'clang'
-    if sys.platform == 'darwin':
-      projects += ';libcxx;compiler-rt'
 
     instrument_args = base_cmake_args + [
         '-DLLVM_ENABLE_PROJECTS=' + projects,
@@ -896,7 +914,7 @@ def main():
                 '-target', 'x86_64-unknown-unknown', '-O2', '-g', '-std=c++14',
                  '-fno-exceptions', '-fno-rtti', '-w', '-c', training_source]
     if sys.platform == 'darwin':
-      train_cmd.extend(['-stdlib=libc++', '-isysroot', isysroot])
+      train_cmd.extend(['-isysroot', isysroot])
     RunCommand(train_cmd, msvc_arch='x64')
 
     # Merge profiles.
@@ -906,49 +924,7 @@ def main():
                                        '*.profraw')), msvc_arch='x64')
     print('Profile generated.')
 
-  compiler_rt_args = [
-      # Build crtbegin/crtend. It's just two tiny TUs, so just enable this
-      # everywhere, even though we only need it on Linux.
-      '-DCOMPILER_RT_BUILD_CRT=ON',
-      '-DCOMPILER_RT_BUILD_LIBFUZZER=OFF',
-      '-DCOMPILER_RT_BUILD_MEMPROF=OFF',
-      '-DCOMPILER_RT_BUILD_ORC=OFF',
-      '-DCOMPILER_RT_BUILD_PROFILE=ON',
-      '-DCOMPILER_RT_BUILD_SANITIZERS=ON',
-      '-DCOMPILER_RT_BUILD_XRAY=OFF',
-  ]
-  if sys.platform == 'darwin':
-    compiler_rt_args.extend([
-        '-DCOMPILER_RT_ENABLE_IOS=ON',
-        '-DCOMPILER_RT_ENABLE_WATCHOS=OFF',
-        '-DCOMPILER_RT_ENABLE_TVOS=OFF',
-        # armv7 is A5 and earlier, armv7s is A6+ (2012 and later, before 64-bit
-        # iPhones). armv7k is Apple Watch, which we don't need.
-        '-DDARWIN_ios_ARCHS=armv7;armv7s;arm64',
-        '-DDARWIN_iossim_ARCHS=i386;x86_64;arm64',
-        # We don't need 32-bit intel support for macOS, we only ship 64-bit.
-        '-DDARWIN_osx_ARCHS=arm64;x86_64',
-    ])
-
-  if sys.platform == 'win32':
-    # https://crbug.com/1293778
-    compiler_rt_args.append('-DCOMPILER_RT_BUILD_BUILTINS=OFF')
-  else:
-    compiler_rt_args.append('-DCOMPILER_RT_BUILD_BUILTINS=ON')
-
-  # LLVM uses C++11 starting in llvm 3.5. On Linux, this means libstdc++4.7+ is
-  # needed, on OS X it requires libc++. clang only automatically links to libc++
-  # when targeting OS X 10.9+, so add stdlib=libc++ explicitly so clang can run
-  # on OS X versions as old as 10.7.
-  deployment_target = ''
-
-  if sys.platform == 'darwin' and args.bootstrap:
-    # When building on 10.9, /usr/include usually doesn't exist, and while
-    # Xcode's clang automatically sets a sysroot, self-built clangs don't.
-    cflags = ['-isysroot', isysroot]
-    cxxflags = ['-stdlib=libc++'] + cflags
-    ldflags += ['-stdlib=libc++']
-    deployment_target = '10.7'
+  deployment_target = '10.12'
 
   # If building at head, define a macro that plugins can use for #ifdefing
   # out code that builds at head, but not at CLANG_REVISION or vice versa.
@@ -976,7 +952,7 @@ def main():
   if cc is not None:  base_cmake_args.append('-DCMAKE_C_COMPILER=' + cc)
   if cxx is not None: base_cmake_args.append('-DCMAKE_CXX_COMPILER=' + cxx)
   if lld is not None: base_cmake_args.append('-DCMAKE_LINKER=' + lld)
-  cmake_args = base_cmake_args + compiler_rt_args + [
+  cmake_args = base_cmake_args + [
       '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
       '-DCMAKE_CXX_FLAGS=' + ' '.join(cxxflags),
       '-DCMAKE_EXE_LINKER_FLAGS=' + ' '.join(ldflags),
@@ -994,13 +970,11 @@ def main():
   if sys.platform == 'win32':
     cmake_args.append('-DLLVM_ENABLE_ZLIB=FORCE_ON')
 
-  if sys.platform == 'darwin':
-    cmake_args += ['-DCOMPILER_RT_ENABLE_IOS=ON',
-                   '-DSANITIZER_MIN_OSX_VERSION=10.7']
-    if args.build_mac_arm:
-      assert platform.machine() != 'arm64', 'build_mac_arm for cross build only'
-      cmake_args += ['-DCMAKE_OSX_ARCHITECTURES=arm64',
-                     '-DCMAKE_SYSTEM_NAME=Darwin']
+  if args.build_mac_arm:
+    assert platform.machine() != 'arm64', 'build_mac_arm for cross build only'
+    cmake_args += [
+        '-DCMAKE_OSX_ARCHITECTURES=arm64', '-DCMAKE_SYSTEM_NAME=Darwin'
+    ]
 
   # The default LLVM_DEFAULT_TARGET_TRIPLE depends on the host machine.
   # Set it explicitly to make the build of clang more hermetic, and also to
@@ -1023,89 +997,67 @@ def main():
   elif sys.platform == 'win32':
     cmake_args.append('-DLLVM_DEFAULT_TARGET_TRIPLE=x86_64-pc-windows-msvc')
 
-  if os.path.exists(LLVM_BUILD_DIR):
-    RmTree(LLVM_BUILD_DIR)
-  EnsureDirExists(LLVM_BUILD_DIR)
-  os.chdir(LLVM_BUILD_DIR)
-  RunCommand(['cmake'] + cmake_args + [os.path.join(LLVM_DIR, 'llvm')],
-             msvc_arch='x64', env=deployment_env)
-  CopyLibstdcpp(args, LLVM_BUILD_DIR)
-  RunCommand(['ninja'], msvc_arch='x64')
-
-  if chrome_tools:
-    # If any Chromium tools were built, install those now.
-    RunCommand(['ninja', 'cr-install'], msvc_arch='x64')
-
-  if not args.build_mac_arm:
-    VerifyVersionOfBuiltClangMatchesVERSION()
-    VerifyZlibSupport()
-
-  if sys.platform == 'win32':
-    rt_platform = 'windows'
+  # List of (triple, list of CMake vars without '-D').
+  runtimes_triples_args = []
+
+  if sys.platform.startswith('linux'):
+    runtimes_triples_args.append(
+        ('i386-unknown-linux-gnu',
+         compiler_rt_cmake_flags(sanitizers=True, profile=True) + [
+             'CMAKE_SYSROOT=%s' % sysroot_i386,
+         ]))
+    runtimes_triples_args.append(
+        ('x86_64-unknown-linux-gnu',
+         compiler_rt_cmake_flags(sanitizers=True, profile=True) + [
+             'CMAKE_SYSROOT=%s' % sysroot_amd64,
+         ]))
+    runtimes_triples_args.append(
+        # Using "armv7a-unknown-linux-gnueabhihf" confuses the compiler-rt
+        # builtins build, since compiler-rt/cmake/builtin-config-ix.cmake
+        # doesn't include "armv7a" in its `ARM32` list.
+        # TODO(thakis): It seems to work for everything else though, see try
+        # results on
+        # https://chromium-review.googlesource.com/c/chromium/src/+/3702739/4
+        # Maybe it should work for builtins too?
+        ('armv7-unknown-linux-gnueabihf',
+         compiler_rt_cmake_flags(sanitizers=True, profile=True) + [
+             'CMAKE_SYSROOT=%s' % sysroot_arm,
+         ]))
+    runtimes_triples_args.append(
+        ('aarch64-unknown-linux-gnu',
+         compiler_rt_cmake_flags(sanitizers=True, profile=True) + [
+             'CMAKE_SYSROOT=%s' % sysroot_arm64,
+         ]))
+  elif sys.platform == 'win32':
+    runtimes_triples_args.append(
+        ('i386-pc-windows-msvc',
+         compiler_rt_cmake_flags(sanitizers=False, profile=True) + [
+             'LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF',
+         ]))
+    runtimes_triples_args.append(
+        ('x86_64-pc-windows-msvc',
+         compiler_rt_cmake_flags(sanitizers=True, profile=True) + [
+             'LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF',
+         ]))
   elif sys.platform == 'darwin':
-    rt_platform = 'darwin'
-  else:
-    assert sys.platform.startswith('linux')
-    rt_platform = 'linux'
-  rt_lib_dst_dir = os.path.join(LLVM_BUILD_DIR, 'lib', 'clang', RELEASE_VERSION,
-                                'lib', rt_platform)
-  # Make sure the directory exists; this will not be implicilty created if
-  # built with per-target runtime directories.
-  if not os.path.exists(rt_lib_dst_dir):
-    os.makedirs(rt_lib_dst_dir)
-
-  # Do an out-of-tree build of compiler-rt for 32-bit Win clang_rt.profile.lib.
-  if sys.platform == 'win32':
-    compiler_rt_build_dir = os.path.join(LLVM_BUILD_DIR, 'compiler-rt')
-    if os.path.isdir(compiler_rt_build_dir):
-      RmTree(compiler_rt_build_dir)
-    os.makedirs(compiler_rt_build_dir)
-    os.chdir(compiler_rt_build_dir)
-    if 'clang-cl' in cc:
-      # clang-cl produces 64-bit binaries by default.
-      cflags += ['-m32']
-      cxxflags += ['-m32']
-
-    compiler_rt_args = base_cmake_args + [
-        '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
-        '-DCMAKE_CXX_FLAGS=' + ' '.join(cxxflags),
-        '-DCMAKE_EXE_LINKER_FLAGS=' + ' '.join(ldflags),
-        '-DCMAKE_SHARED_LINKER_FLAGS=' + ' '.join(ldflags),
-        '-DCMAKE_MODULE_LINKER_FLAGS=' + ' '.join(ldflags),
-        '-DCOMPILER_RT_BUILD_BUILTINS=OFF',
-        '-DCOMPILER_RT_BUILD_CRT=OFF',
-        '-DCOMPILER_RT_BUILD_LIBFUZZER=OFF',
-        '-DCOMPILER_RT_BUILD_MEMPROF=OFF',
-        '-DCOMPILER_RT_BUILD_ORC=OFF',
-        '-DCOMPILER_RT_BUILD_PROFILE=ON',
-        '-DCOMPILER_RT_BUILD_SANITIZERS=OFF',
-        '-DCOMPILER_RT_BUILD_XRAY=OFF',
-
-        # The libxml2 we built above is 64-bit. Since it's only needed by
-        # lld-link and not compiler-rt, just turn it off down here.
-        '-DLLVM_ENABLE_LIBXML2=OFF',
-    ]
-    RunCommand(['cmake'] + compiler_rt_args +
-               [os.path.join(LLVM_DIR, 'llvm')],
-               msvc_arch='x86', env=deployment_env)
-    RunCommand(['ninja', 'compiler-rt'], msvc_arch='x86')
-
-    # Copy select output to the main tree.
-    rt_lib_src_dir = os.path.join(compiler_rt_build_dir, 'lib', 'clang',
-                                  RELEASE_VERSION, 'lib', rt_platform)
-    # Static and dynamic libraries:
-    CopyDirectoryContents(rt_lib_src_dir, rt_lib_dst_dir)
+    compiler_rt_args = [
+        'SANITIZER_MIN_OSX_VERSION=' + deployment_target,
+        'COMPILER_RT_ENABLE_MACCATALYST=ON',
+        'COMPILER_RT_ENABLE_IOS=ON',
+        'COMPILER_RT_ENABLE_WATCHOS=OFF',
+        'COMPILER_RT_ENABLE_TVOS=OFF',
+        'DARWIN_ios_ARCHS=arm64',
+        'DARWIN_iossim_ARCHS=arm64;x86_64',
+        'DARWIN_osx_ARCHS=arm64;x86_64',
+    ] + compiler_rt_cmake_flags(sanitizers=True, profile=True)
+    # compiler-rt is built for all platforms/arches with a single
+    # configuration, we should only specify one target triple. 'default' is
+    # specially handled.
+    runtimes_triples_args.append(('default', compiler_rt_args))
 
   if args.with_android:
-    # TODO(thakis): Now that the NDK uses clang, try to build all archs in
-    # one LLVM build instead of building 3 times.
     toolchain_dir = ANDROID_NDK_DIR + '/toolchains/llvm/prebuilt/linux-x86_64'
     for target_arch in ['aarch64', 'arm', 'i686', 'x86_64']:
-      # Build compiler-rt runtimes needed for Android in a separate build tree.
-      build_dir = os.path.join(LLVM_BUILD_DIR, 'android-' + target_arch)
-      if not os.path.exists(build_dir):
-        os.mkdir(os.path.join(build_dir))
-      os.chdir(build_dir)
       target_triple = target_arch
       if target_arch == 'arm':
         target_triple = 'armv7'
@@ -1114,16 +1066,8 @@ def main():
         api_level = '21'
       target_triple += '-linux-android' + api_level
       cflags = [
-          '--target=' + target_triple,
           '--sysroot=%s/sysroot' % toolchain_dir,
 
-          # pylint: disable=line-too-long
-          # android_ndk/toolchains/llvm/prebuilt/linux-x86_64/aarch64-linux-android/bin/ld
-          # depends on a newer version of libxml2.so than what's available on
-          # the bots. To make things work, use our just-built lld as linker.
-          # pylint: enable=line-too-long
-          '-fuse-ld=lld',
-
           # We don't have an unwinder ready, and don't need it either.
           '--unwindlib=none',
       ]
@@ -1132,73 +1076,26 @@ def main():
         # Use PAC/BTI instructions for AArch64
         cflags += [ '-mbranch-protection=standard' ]
 
-      android_args = base_cmake_args + [
-        '-DCMAKE_C_COMPILER=' + os.path.join(LLVM_BUILD_DIR, 'bin/clang'),
-        '-DCMAKE_CXX_COMPILER=' + os.path.join(LLVM_BUILD_DIR, 'bin/clang++'),
-        '-DLLVM_CONFIG_PATH=' + os.path.join(LLVM_BUILD_DIR, 'bin/llvm-config'),
-        '-DCMAKE_C_FLAGS=' + ' '.join(cflags),
-        '-DCMAKE_CXX_FLAGS=' + ' '.join(cflags),
-        '-DCMAKE_ASM_FLAGS=' + ' '.join(cflags),
-        '-DCOMPILER_RT_BUILD_BUILTINS=ON',
-        '-DCOMPILER_RT_BUILD_CRT=OFF',
-        '-DCOMPILER_RT_BUILD_LIBFUZZER=OFF',
-        '-DCOMPILER_RT_BUILD_MEMPROF=OFF',
-        '-DCOMPILER_RT_BUILD_ORC=OFF',
-        '-DCOMPILER_RT_BUILD_PROFILE=OFF',
-        '-DCOMPILER_RT_BUILD_SANITIZERS=OFF',
-        '-DCOMPILER_RT_BUILD_XRAY=OFF',
-        '-DSANITIZER_CXX_ABI=libcxxabi',
-        '-DCMAKE_SHARED_LINKER_FLAGS=-Wl,-u__cxa_demangle',
-        '-DANDROID=1'
-
-        # These are necessary because otherwise CMake tries to build an
-        # executable to test to see if the compiler is working, but in doing so,
-        # it links against the builtins.a that we're about to build.
-        '-DCMAKE_CXX_COMPILER_WORKS=ON',
-        '-DCMAKE_C_COMPILER_WORKS=ON',
-        '-DCMAKE_ASM_COMPILER_WORKS=ON',
+      android_args = compiler_rt_cmake_flags(sanitizers=True, profile=True) + [
+          'LLVM_ENABLE_RUNTIMES=compiler-rt',
+          # On Android, we want DWARF info for the builtins for unwinding. See
+          # crbug.com/1311807.
+          'CMAKE_BUILD_TYPE=RelWithDebInfo',
+          'CMAKE_C_FLAGS=' + ' '.join(cflags),
+          'CMAKE_CXX_FLAGS=' + ' '.join(cflags),
+          'CMAKE_ASM_FLAGS=' + ' '.join(cflags),
+          'COMPILER_RT_USE_BUILTINS_LIBRARY=ON',
+          'SANITIZER_CXX_ABI=libcxxabi',
+          'CMAKE_SHARED_LINKER_FLAGS=-Wl,-u__cxa_demangle',
+          'ANDROID=1',
+          'LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=OFF',
+          'LLVM_INCLUDE_TESTS=OFF',
+          # This prevents static_asserts from firing in 32-bit builds.
+          # TODO: remove once we only support API >=24.
+          'ANDROID_NATIVE_API_LEVEL=' + api_level,
       ]
 
-      # First build the builtins and copy to the main build tree.
-      RunCommand(
-          ['cmake'] + android_args +
-          # On Android, we want DWARF info for the builtins for
-          # unwinding. See crbug.com/1311807.
-          ['-DCMAKE_BUILD_TYPE=RelWithDebInfo'] +
-          [os.path.join(COMPILER_RT_DIR, 'lib', 'builtins')])
-      builtins_a = 'lib/linux/libclang_rt.builtins-%s-android.a' % target_arch
-      RunCommand(['ninja', builtins_a])
-      shutil.copy(builtins_a, rt_lib_dst_dir)
-
-      # With the builtins in place, we can build the other runtimes.
-      build_dir_2 = build_dir + '-phase2'
-      if not os.path.exists(build_dir_2):
-        os.mkdir(os.path.join(build_dir_2))
-      os.chdir(build_dir_2)
-
-      android_args.extend([
-        '-DCOMPILER_RT_BUILD_BUILTINS=OFF',
-        '-DCOMPILER_RT_USE_BUILTINS_LIBRARY=ON',
-        '-DCOMPILER_RT_BUILD_PROFILE=ON',
-        '-DCOMPILER_RT_BUILD_SANITIZERS=ON',
-      ])
-      RunCommand(['cmake'] + android_args + [COMPILER_RT_DIR])
-
-      libs_want = [
-          'lib/linux/libclang_rt.asan-{0}-android.so',
-          'lib/linux/libclang_rt.asan_static-{0}-android.a',
-          'lib/linux/libclang_rt.ubsan_standalone-{0}-android.so',
-          'lib/linux/libclang_rt.profile-{0}-android.a',
-      ]
-      # Only build HWASan for AArch64.
-      if target_arch == 'aarch64':
-        libs_want += ['lib/linux/libclang_rt.hwasan-{0}-android.so']
-      libs_want = [lib.format(target_arch) for lib in libs_want]
-      RunCommand(['ninja'] + libs_want)
-
-      # And copy them into the main build tree.
-      for p in libs_want:
-        shutil.copy(p, rt_lib_dst_dir)
+      runtimes_triples_args.append((target_triple, android_args))
 
   if args.with_fuchsia:
     # Fuchsia links against libclang_rt.builtins-<arch>.a instead of libgcc.a.
@@ -1206,112 +1103,68 @@ def main():
       fuchsia_arch_name = {'aarch64': 'arm64', 'x86_64': 'x64'}[target_arch]
       toolchain_dir = os.path.join(
           FUCHSIA_SDK_DIR, 'arch', fuchsia_arch_name, 'sysroot')
-      # Build clang_rt runtime for Fuchsia in a separate build tree.
-      build_dir = os.path.join(LLVM_BUILD_DIR, 'fuchsia-' + target_arch)
-      if not os.path.exists(build_dir):
-        os.mkdir(os.path.join(build_dir))
-      os.chdir(build_dir)
-      target_spec = target_arch + '-unknown-fuchsia'
-      if args.build_mac_arm:
-        # Just-built clang can't run (it's an arm binary on an intel host), so
-        # use the bootstrap compiler instead.
-        host_path = LLVM_BOOTSTRAP_INSTALL_DIR
-      else:
-        host_path = LLVM_BUILD_DIR
-      # TODO(thakis): Might have to pass -B here once sysroot contains
-      # binaries (e.g. gas for arm64?)
-      fuchsia_args = base_cmake_args + [
-        '-DCMAKE_C_COMPILER=' + os.path.join(host_path, 'bin/clang'),
-        '-DCMAKE_CXX_COMPILER=' + os.path.join(host_path, 'bin/clang++'),
-        '-DCMAKE_LINKER=' + os.path.join(host_path, 'bin/clang'),
-        '-DCMAKE_AR=' + os.path.join(host_path, 'bin/llvm-ar'),
-        '-DLLVM_CONFIG_PATH=' + os.path.join(host_path, 'bin/llvm-config'),
-        '-DCMAKE_SYSTEM_NAME=Fuchsia',
-        '-DCMAKE_CXX_COMPILER_TARGET=' + target_spec,
-        '-DCMAKE_C_COMPILER_TARGET=' + target_spec,
-        '-DCMAKE_ASM_COMPILER_TARGET=' + target_spec,
-        '-DCOMPILER_RT_BUILD_BUILTINS=ON',
-        '-DCOMPILER_RT_BUILD_CRT=OFF',
-        '-DCOMPILER_RT_BUILD_LIBFUZZER=OFF',
-        '-DCOMPILER_RT_BUILD_MEMPROF=OFF',
-        '-DCOMPILER_RT_BUILD_ORC=OFF',
-        '-DCOMPILER_RT_BUILD_PROFILE=OFF',
-        '-DCOMPILER_RT_BUILD_SANITIZERS=OFF',
-        '-DCOMPILER_RT_BUILD_XRAY=OFF',
-        '-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON',
-        '-DCMAKE_SYSROOT=%s' % toolchain_dir,
-        # TODO(thakis|scottmg): Use PER_TARGET_RUNTIME_DIR for all platforms.
-        # https://crbug.com/882485.
-        '-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON',
-
-        # These are necessary because otherwise CMake tries to build an
-        # executable to test to see if the compiler is working, but in doing so,
-        # it links against the builtins.a that we're about to build.
-        '-DCMAKE_CXX_COMPILER_WORKS=ON',
-        '-DCMAKE_C_COMPILER_WORKS=ON',
-        '-DCMAKE_ASM_COMPILER_WORKS=ON',
-        ]
-      RunCommand(['cmake'] +
-                 fuchsia_args +
-                 [os.path.join(COMPILER_RT_DIR, 'lib', 'builtins')])
-      builtins_a = 'libclang_rt.builtins.a'
-      RunCommand(['ninja', builtins_a])
-
-      # And copy it into the main build tree.
-      fuchsia_lib_dst_dir = os.path.join(LLVM_BUILD_DIR, 'lib', 'clang',
-                                         RELEASE_VERSION, 'lib', target_spec)
-      if not os.path.exists(fuchsia_lib_dst_dir):
-        os.makedirs(fuchsia_lib_dst_dir)
-      CopyFile(os.path.join(build_dir, 'lib', target_spec, builtins_a),
-               fuchsia_lib_dst_dir)
-
+      target_triple = target_arch + '-unknown-fuchsia'
       # Build the Fuchsia profile and asan runtimes.  This is done after the rt
       # builtins have been created because the CMake build runs link checks that
       # require that the builtins already exist to succeed.
       # TODO(thakis): Figure out why this doesn't build with the stage0
       # compiler in arm cross builds.
-      if target_arch == 'x86_64' and not args.build_mac_arm:
-        fuchsia_args.extend([
-            '-DCOMPILER_RT_BUILD_BUILTINS=OFF',
-            '-DCOMPILER_RT_BUILD_PROFILE=ON',
-        ])
-        # Build the asan runtime only on non-Mac platforms.  Macs are excluded
-        # because the asan install changes library RPATHs which CMake only
-        # supports on ELF platforms and MacOS uses Mach-O instead of ELF.
-        if sys.platform != 'darwin':
-          fuchsia_args.extend([
-              '-DCOMPILER_RT_BUILD_SANITIZERS=ON',
-              '-DSANITIZER_NO_UNDEFINED_SYMBOLS=OFF',
-          ])
-        build_phase2_dir = os.path.join(LLVM_BUILD_DIR,
-                                         'fuchsia-phase2-' + target_arch)
-        if not os.path.exists(build_phase2_dir):
-          os.mkdir(os.path.join(build_phase2_dir))
-        os.chdir(build_phase2_dir)
-        RunCommand(['cmake'] +
-                   fuchsia_args +
-                   [COMPILER_RT_DIR])
-        profile_a = 'libclang_rt.profile.a'
-        asan_preinit_a = 'libclang_rt.asan-preinit.a'
-        asan_static_a = 'libclang_rt.asan_static.a'
-        asan_so = 'libclang_rt.asan.so'
-        ninja_command = ['ninja', profile_a]
-        if sys.platform != 'darwin':
-          ninja_command.append(asan_so)
-          ninja_command.append(asan_preinit_a)
-          ninja_command.append(asan_static_a)
-        RunCommand(ninja_command)
-        CopyFile(os.path.join(build_phase2_dir, 'lib', target_spec, profile_a),
-                              fuchsia_lib_dst_dir)
-        if sys.platform != 'darwin':
-          CopyFile(os.path.join(build_phase2_dir, 'lib', target_spec, asan_so),
-                   fuchsia_lib_dst_dir)
-          CopyFile(
-              os.path.join(build_phase2_dir, 'lib', target_spec,
-                           asan_preinit_a), fuchsia_lib_dst_dir)
-          CopyFile(
-              os.path.join(build_phase2_dir, 'lib', target_spec, asan_static_a),
-              fuchsia_lib_dst_dir)
+      build_profile = target_arch == 'x86_64' and not args.build_mac_arm
+      # Build the asan runtime only on non-Mac platforms.  Macs are excluded
+      # because the asan install changes library RPATHs which CMake only
+      # supports on ELF platforms and MacOS uses Mach-O instead of ELF.
+      build_sanitizers = build_profile and sys.platform != 'darwin'
+      # TODO(thakis): Might have to pass -B here once sysroot contains
+      # binaries (e.g. gas for arm64?)
+      fuchsia_args = compiler_rt_cmake_flags(
+          sanitizers=build_sanitizers, profile=build_profile
+      ) + [
+          'LLVM_ENABLE_RUNTIMES=compiler-rt',
+          'CMAKE_SYSTEM_NAME=Fuchsia',
+          'CMAKE_SYSROOT=%s' % toolchain_dir,
+          # TODO(thakis|scottmg): Use PER_TARGET_RUNTIME_DIR for all platforms.
+          # https://crbug.com/882485.
+          'LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON',
+      ]
+      if build_sanitizers:
+        fuchsia_args.append('SANITIZER_NO_UNDEFINED_SYMBOLS=OFF')
+
+      runtimes_triples_args.append((target_triple, fuchsia_args))
+
+  # Convert FOO=BAR CMake flags per triple into
+  # -DBUILTINS_$triple_FOO=BAR/-DRUNTIMES_$triple_FOO=BAR and build up
+  # -DLLVM_BUILTIN_TARGETS/-DLLVM_RUNTIME_TARGETS.
+  all_triples = ''
+  for (triple, a) in runtimes_triples_args:
+    all_triples += ';' + triple
+    for arg in a:
+      assert not arg.startswith('-')
+      # 'default' is specially handled to pass through relevant CMake flags.
+      if triple == 'default':
+        cmake_args.append('-D' + arg)
+      else:
+        cmake_args.append('-DBUILTINS_' + triple + '_' + arg)
+        cmake_args.append('-DRUNTIMES_' + triple + '_' + arg)
+  cmake_args.append('-DLLVM_BUILTIN_TARGETS=' + all_triples)
+  cmake_args.append('-DLLVM_RUNTIME_TARGETS=' + all_triples)
+
+  if os.path.exists(LLVM_BUILD_DIR):
+    RmTree(LLVM_BUILD_DIR)
+  EnsureDirExists(LLVM_BUILD_DIR)
+  os.chdir(LLVM_BUILD_DIR)
+  RunCommand(['cmake'] + cmake_args + [os.path.join(LLVM_DIR, 'llvm')],
+             msvc_arch='x64',
+             env=deployment_env)
+  CopyLibstdcpp(args, LLVM_BUILD_DIR)
+  RunCommand(['ninja'], msvc_arch='x64')
+
+  if chrome_tools:
+    # If any Chromium tools were built, install those now.
+    RunCommand(['ninja', 'cr-install'], msvc_arch='x64')
+
+  if not args.build_mac_arm:
+    VerifyVersionOfBuiltClangMatchesVERSION()
+    VerifyZlibSupport()
 
   # Run tests.
   if (not args.build_mac_arm and
@@ -1319,11 +1172,16 @@ def main():
     RunCommand(['ninja', '-C', LLVM_BUILD_DIR, 'cr-check-all'], msvc_arch='x64')
 
   if not args.build_mac_arm and args.run_tests:
-    test_targets = [ 'check-all' ]
-    if sys.platform == 'darwin':
-      # TODO(thakis): Run check-all on Darwin too, https://crbug.com/959361
-      test_targets = [ 'check-llvm', 'check-clang', 'check-lld' ]
-    RunCommand(['ninja', '-C', LLVM_BUILD_DIR] + test_targets, msvc_arch='x64')
+    env = None
+    if sys.platform.startswith('linux'):
+      env = os.environ.copy()
+      # See SANITIZER_OVERRIDE_INTERCEPTORS above: We disable crypt_r()
+      # interception, so its tests can't pass.
+      env['LIT_FILTER_OUT'] = ('^SanitizerCommon-(a|l|m|ub|t)san-x86_64-Linux' +
+                               ' :: Linux/crypt_r.cpp$')
+    RunCommand(['ninja', '-C', LLVM_BUILD_DIR, 'check-all'],
+               env=env,
+               msvc_arch='x64')
 
   WriteStampFile(PACKAGE_VERSION, STAMP_FILE)
   WriteStampFile(PACKAGE_VERSION, FORCE_HEAD_REVISION_FILE)
diff --git a/chromium/tools/clang/scripts/goma_ld.py b/chromium/tools/clang/scripts/goma_ld.py
index 21a7dd2286c..123da699881 100755
--- a/chromium/tools/clang/scripts/goma_ld.py
+++ b/chromium/tools/clang/scripts/goma_ld.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 # 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.
@@ -9,17 +9,12 @@
 # E.g. original: clang++ -o foo foo.o
 # Becomes: goma-ld clang++ -o foo foo.o
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
-import goma_link
-
 import os
 import re
 import sys
 
+import goma_link
+
 
 class GomaLinkUnix(goma_link.GomaLinkBase):
   # Target-platform-specific constants.
diff --git a/chromium/tools/clang/scripts/goma_link.py b/chromium/tools/clang/scripts/goma_link.py
index a101dc93bfd..5d7339fbf91 100755
--- a/chromium/tools/clang/scripts/goma_link.py
+++ b/chromium/tools/clang/scripts/goma_link.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 # 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.
@@ -9,11 +9,6 @@
 # E.g. original: lld-link -out:foo foo.obj
 # Becomes: goma_link.py lld-link -out:foo foo.obj
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import argparse
 import errno
 import io
@@ -26,14 +21,6 @@ from collections import namedtuple
 from pipes import quote as shquote
 from tempfile import NamedTemporaryFile
 
-# Python 2 has int and long, and we want to use long.  Python 3 only has int,
-# which is like long in Python 2.  So we check if long is defined, and, if not,
-# define it to be the same as int.
-try:
-  long
-except NameError:
-  long = int
-
 # Type returned by analyze_args.
 AnalyzeArgsResult = namedtuple('AnalyzeArgsResult', [
     'output', 'linker', 'compiler', 'splitfile', 'index_inputs', 'index_params',
@@ -124,13 +111,13 @@ def names_in_archive(path):
       f.seek(32, io.SEEK_CUR)
       m = re.match(b'/([0-9]+)', file_id)
       if long_names and m:
-        name_pos = long(m.group(1))
+        name_pos = int(m.group(1))
         name_end = long_names.find(b'/\n', name_pos)
         name = long_names[name_pos:name_end]
       else:
         name = file_id
       try:
-        size = long(f.read(10))
+        size = int(f.read(10))
       except:
         sys.stderr.write('While parsing %r, pos %r\n' % (path, f.tell()))
         raise
diff --git a/chromium/tools/clang/scripts/package.py b/chromium/tools/clang/scripts/package.py
index 32a79a5e3e5..bd8782125c3 100755
--- a/chromium/tools/clang/scripts/package.py
+++ b/chromium/tools/clang/scripts/package.py
@@ -4,13 +4,12 @@
 # found in the LICENSE file.
 
 """This script will check out llvm and clang, and then package the results up
-to a tgz file."""
-
-from __future__ import print_function
+to a number of tarballs."""
 
 import argparse
 import fnmatch
 import itertools
+import lzma
 import multiprocessing.dummy
 import os
 import platform
@@ -101,16 +100,24 @@ def PackageInArchive(directory_path, archive_path):
       if not os.path.islink(file_path):
         subprocess.call(['strip', file_path])
 
-  with tarfile.open(archive_path, 'w:gz') as tar:
-    for f in os.listdir(directory_path):
-      tar.add(os.path.join(directory_path, f),
-              arcname=f, filter=PrintTarProgress)
+  with tarfile.open(archive_path + '.tar.xz',
+                    'w:xz',
+                    preset=9 | lzma.PRESET_EXTREME) as tar_xz:
+    with tarfile.open(archive_path + '.tgz', 'w:gz') as tar_gz:
+      for f in sorted(os.listdir(directory_path)):
+        tar_xz.add(os.path.join(directory_path, f),
+                   arcname=f,
+                   filter=PrintTarProgress)
+        # TODO(crbug.com/1261812) Stop making gzip'ed archives once the
+        # goma/reclient push processes are updated to consume the .xz files
+        # instead.
+        tar_gz.add(os.path.join(directory_path, f), arcname=f)
 
 
 def MaybeUpload(do_upload, filename, gcs_platform, extra_gsutil_args=[]):
   gsutil_args = ['cp'] + extra_gsutil_args + [
-      '-a', 'public-read', filename,
-      'gs://chromium-browser-clang-staging/%s/%s' % (gcs_platform, filename)
+      '-n', '-a', 'public-read', filename,
+      'gs://chromium-browser-clang-staging/%s/' % (gcs_platform)
   ]
   if do_upload:
     print('Uploading %s to Google Cloud Storage...' % filename)
@@ -256,20 +263,23 @@ def main():
     ])
   else:
     want.extend([
-      'bin/clang',
+        'bin/clang',
+
+        # Add LLD.
+        'bin/lld',
 
-      # Add LLD.
-      'bin/lld',
+        # Add llvm-ar for LTO.
+        'bin/llvm-ar',
 
-      # Add llvm-ar for LTO.
-      'bin/llvm-ar',
+        # llvm-ml for Windows cross builds.
+        'bin/llvm-ml',
 
-      # Include libclang_rt.builtins.a for Fuchsia targets.
-      'lib/clang/$V/lib/aarch64-unknown-fuchsia/libclang_rt.builtins.a',
-      'lib/clang/$V/lib/x86_64-unknown-fuchsia/libclang_rt.builtins.a',
+        # Include libclang_rt.builtins.a for Fuchsia targets.
+        'lib/clang/$V/lib/aarch64-unknown-fuchsia/libclang_rt.builtins.a',
+        'lib/clang/$V/lib/x86_64-unknown-fuchsia/libclang_rt.builtins.a',
 
-      # Add llvm-readobj (symlinked from llvm-readelf) for extracting SONAMEs.
-      'bin/llvm-readobj',
+        # Add llvm-readobj (symlinked from llvm-readelf) for extracting SONAMEs.
+        'bin/llvm-readobj',
     ])
     if not args.build_mac_arm:
       # TODO(thakis): Figure out why this doesn't build in --build-mac-arm
@@ -343,9 +353,15 @@ def main():
         'lib/clang/$V/lib/linux/libclang_rt.builtins-x86_64-android.a',
 
         # Builtins for Lacros (and potentially Linux, but not used there atm).
+        'lib/clang/$V/lib/aarch64-unknown-linux-gnu/libclang_rt.builtins.a',
+        'lib/clang/$V/lib/armv7-unknown-linux-gnueabihf/libclang_rt.builtins.a',
         'lib/clang/$V/lib/x86_64-unknown-linux-gnu/libclang_rt.builtins.a',
 
         # crtstart/crtend for Linux and Lacros.
+        'lib/clang/$V/lib/aarch64-unknown-linux-gnu/clang_rt.crtbegin.o',
+        'lib/clang/$V/lib/aarch64-unknown-linux-gnu/clang_rt.crtend.o',
+        'lib/clang/$V/lib/armv7-unknown-linux-gnueabihf/clang_rt.crtbegin.o',
+        'lib/clang/$V/lib/armv7-unknown-linux-gnueabihf/clang_rt.crtend.o',
         'lib/clang/$V/lib/x86_64-unknown-linux-gnu/clang_rt.crtbegin.o',
         'lib/clang/$V/lib/x86_64-unknown-linux-gnu/clang_rt.crtend.o',
 
@@ -361,9 +377,11 @@ def main():
         'lib/clang/$V/lib/x86_64-unknown-linux-gnu/libclang_rt.msan_cxx.a.syms',
 
         # Profile runtime (used by profiler and code coverage).
+        'lib/clang/$V/lib/aarch64-unknown-linux-gnu/libclang_rt.profile.a',
+        'lib/clang/$V/lib/armv7-unknown-linux-gnueabihf/libclang_rt.profile.a',
         'lib/clang/$V/lib/i386-unknown-linux-gnu/libclang_rt.profile.a',
-        'lib/clang/$V/lib/linux/libclang_rt.profile-i686-android.a',
         'lib/clang/$V/lib/x86_64-unknown-linux-gnu/libclang_rt.profile.a',
+        'lib/clang/$V/lib/linux/libclang_rt.profile-i686-android.a',
         'lib/clang/$V/lib/linux/libclang_rt.profile-aarch64-android.a',
         'lib/clang/$V/lib/linux/libclang_rt.profile-arm-android.a',
 
@@ -516,19 +534,16 @@ def main():
 
     # Make `--target=*-cros-linux-gnu` work with
     # LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON.
-    os.symlink(
-        'x86_64-unknown-linux-gnu',
-        os.path.join(pdir, 'lib', 'clang', RELEASE_VERSION, 'lib',
-                     'x86_64-cros-linux-gnu'))
-
-  # Copy libc++ headers.
-  if sys.platform == 'darwin':
-    shutil.copytree(os.path.join(LLVM_BOOTSTRAP_INSTALL_DIR, 'include', 'c++'),
-                    os.path.join(pdir, 'include', 'c++'))
+    for arch, abi in [('armv7', 'gnueabihf'), ('aarch64', 'gnu'),
+                      ('x86_64', 'gnu')]:
+      old = '%s-unknown-linux-%s' % (arch, abi)
+      new = old.replace('unknown', 'cros').replace('armv7', 'armv7a')
+      os.symlink(
+          old, os.path.join(pdir, 'lib', 'clang', RELEASE_VERSION, 'lib', new))
 
   # Create main archive.
-  PackageInArchive(pdir, pdir + '.tgz')
-  MaybeUpload(args.upload, pdir + '.tgz', gcs_platform)
+  PackageInArchive(pdir, pdir)
+  MaybeUpload(args.upload, pdir + '.t*z', gcs_platform)
 
   # Upload build log next to it.
   os.rename('buildlog.txt', pdir + '-buildlog.txt')
@@ -545,8 +560,8 @@ def main():
   for filename in ['llvm-cov', 'llvm-profdata']:
     shutil.copy(os.path.join(LLVM_RELEASE_DIR, 'bin', filename + exe_ext),
                 os.path.join(code_coverage_dir, 'bin'))
-  PackageInArchive(code_coverage_dir, code_coverage_dir + '.tgz')
-  MaybeUpload(args.upload, code_coverage_dir + '.tgz', gcs_platform)
+  PackageInArchive(code_coverage_dir, code_coverage_dir)
+  MaybeUpload(args.upload, code_coverage_dir + '.t*z', gcs_platform)
 
   # Zip up llvm-objdump and related tools for sanitizer coverage and Supersize.
   objdumpdir = 'llvmobjdump-' + stamp
@@ -565,8 +580,8 @@ def main():
     f.write('\n')
   if sys.platform != 'win32':
     os.symlink('llvm-objdump', os.path.join(objdumpdir, 'bin', 'llvm-otool'))
-  PackageInArchive(objdumpdir, objdumpdir + '.tgz')
-  MaybeUpload(args.upload, objdumpdir + '.tgz', gcs_platform)
+  PackageInArchive(objdumpdir, objdumpdir)
+  MaybeUpload(args.upload, objdumpdir + '.t*z', gcs_platform)
 
   # Zip up clang-tidy for users who opt into it, and Tricium.
   clang_tidy_dir = 'clang-tidy-' + stamp
@@ -574,8 +589,8 @@ def main():
   os.makedirs(os.path.join(clang_tidy_dir, 'bin'))
   shutil.copy(os.path.join(LLVM_RELEASE_DIR, 'bin', 'clang-tidy' + exe_ext),
               os.path.join(clang_tidy_dir, 'bin'))
-  PackageInArchive(clang_tidy_dir, clang_tidy_dir + '.tgz')
-  MaybeUpload(args.upload, clang_tidy_dir + '.tgz', gcs_platform)
+  PackageInArchive(clang_tidy_dir, clang_tidy_dir)
+  MaybeUpload(args.upload, clang_tidy_dir + '.t*z', gcs_platform)
 
   # Zip up clang-format so we can update it (separately from the clang roll).
   clang_format_dir = 'clang-format-' + stamp
@@ -583,8 +598,8 @@ def main():
   os.makedirs(os.path.join(clang_format_dir, 'bin'))
   shutil.copy(os.path.join(LLVM_RELEASE_DIR, 'bin', 'clang-format' + exe_ext),
               os.path.join(clang_format_dir, 'bin'))
-  PackageInArchive(clang_format_dir, clang_format_dir + '.tgz')
-  MaybeUpload(args.upload, clang_format_dir + '.tgz', gcs_platform)
+  PackageInArchive(clang_format_dir, clang_format_dir)
+  MaybeUpload(args.upload, clang_format_dir + '.t*z', gcs_platform)
 
   # Zip up clang-libs for users who opt into it. We want Clang and LLVM headers
   # and libs, as well as a couple binaries. The LLVM parts are needed by the
@@ -635,8 +650,8 @@ def main():
       if fnmatch.fnmatch(lib_path, lib_want):
         shutil.copy(os.path.join(LLVM_BOOTSTRAP_DIR, 'lib', lib_path),
                     os.path.join(clang_libs_dir, 'lib'))
-  PackageInArchive(clang_libs_dir, clang_libs_dir + '.tgz')
-  MaybeUpload(args.upload, clang_libs_dir + '.tgz', gcs_platform)
+  PackageInArchive(clang_libs_dir, clang_libs_dir)
+  MaybeUpload(args.upload, clang_libs_dir + '.t*z', gcs_platform)
 
   if sys.platform == 'darwin':
     # dsymutil isn't part of the main zip, and it gets periodically
@@ -647,8 +662,8 @@ def main():
     os.makedirs(os.path.join(dsymdir, 'bin'))
     shutil.copy(os.path.join(LLVM_RELEASE_DIR, 'bin', 'dsymutil'),
                 os.path.join(dsymdir, 'bin'))
-    PackageInArchive(dsymdir, dsymdir + '.tgz')
-    MaybeUpload(args.upload, dsymdir + '.tgz', gcs_platform)
+    PackageInArchive(dsymdir, dsymdir)
+    MaybeUpload(args.upload, dsymdir + '.t*z', gcs_platform)
 
   # Zip up the translation_unit tool.
   translation_unit_dir = 'translation_unit-' + stamp
@@ -657,8 +672,8 @@ def main():
   shutil.copy(os.path.join(LLVM_RELEASE_DIR, 'bin', 'translation_unit' +
                            exe_ext),
               os.path.join(translation_unit_dir, 'bin'))
-  PackageInArchive(translation_unit_dir, translation_unit_dir + '.tgz')
-  MaybeUpload(args.upload, translation_unit_dir + '.tgz', gcs_platform)
+  PackageInArchive(translation_unit_dir, translation_unit_dir)
+  MaybeUpload(args.upload, translation_unit_dir + '.t*z', gcs_platform)
 
   # Zip up the libclang binaries.
   libclang_dir = 'libclang-' + stamp
@@ -672,8 +687,8 @@ def main():
     shutil.copy(os.path.join(LLVM_DIR, 'clang', 'bindings', 'python', 'clang',
                              filename),
                 os.path.join(libclang_dir, 'bindings', 'python', 'clang'))
-  PackageInArchive(libclang_dir, libclang_dir + '.tgz')
-  MaybeUpload(args.upload, libclang_dir + '.tgz', gcs_platform)
+  PackageInArchive(libclang_dir, libclang_dir)
+  MaybeUpload(args.upload, libclang_dir + '.t*z', gcs_platform)
 
   if sys.platform == 'win32' and args.upload:
     binaries = [f for f in want if f.endswith('.exe') or f.endswith('.dll')]
diff --git a/chromium/tools/clang/scripts/process_crashreports.py b/chromium/tools/clang/scripts/process_crashreports.py
index d6d7cd9104f..020530460a1 100755
--- a/chromium/tools/clang/scripts/process_crashreports.py
+++ b/chromium/tools/clang/scripts/process_crashreports.py
@@ -66,6 +66,10 @@ def ProcessCrashreport(base, source):
     subprocess.check_call([sys.executable, GSUTIL, '-q', 'cp', tmp_name, dest])
     print('done')
     print('    %s' % dest)
+  except subprocess.CalledProcessError as e:
+    print('upload failed; if it was due to missing permissions, try running')
+    print('download_from_google_storage --config')
+    print('and then try again')
   finally:
     if tmp_name:
       os.remove(tmp_name)
diff --git a/chromium/tools/clang/scripts/sanitizers/sanitizer_intercept_overriders.h b/chromium/tools/clang/scripts/sanitizers/sanitizer_intercept_overriders.h
new file mode 100644
index 00000000000..bfd0f6b5b98
--- /dev/null
+++ b/chromium/tools/clang/scripts/sanitizers/sanitizer_intercept_overriders.h
@@ -0,0 +1,5 @@
+// Workaround for https://crbug.com/1302636#c49, #c55
+#ifdef SANITIZER_INTERCEPT_CRYPT_R
+#undef SANITIZER_INTERCEPT_CRYPT_R
+#define SANITIZER_INTERCEPT_CRYPT_R 0
+#endif
\ No newline at end of file
diff --git a/chromium/tools/clang/scripts/update.py b/chromium/tools/clang/scripts/update.py
index a6af0980390..c8703580d32 100755
--- a/chromium/tools/clang/scripts/update.py
+++ b/chromium/tools/clang/scripts/update.py
@@ -35,11 +35,11 @@ import zlib
 # https://chromium.googlesource.com/chromium/src/+/main/docs/updating_clang.md
 # Reverting problematic clang rolls is safe, though.
 # This is the output of `git describe` and is usable as a commit-ish.
-CLANG_REVISION = 'llvmorg-15-init-11722-g3f3a235a'
-CLANG_SUB_REVISION = 2
+CLANG_REVISION = 'llvmorg-16-init-907-g8b740747'
+CLANG_SUB_REVISION = 1
 
 PACKAGE_VERSION = '%s-%s' % (CLANG_REVISION, CLANG_SUB_REVISION)
-RELEASE_VERSION = '15.0.0'
+RELEASE_VERSION = '16.0.0'
 
 CDS_URL = os.environ.get('CDS_CLANG_BUCKET_OVERRIDE',
     'https://commondatastorage.googleapis.com/chromium-browser-clang')
@@ -140,6 +140,8 @@ def DownloadUrl(url, output_file):
           e, urllib.error.HTTPError) and e.code == 404:
         raise e
       num_retries -= 1
+      output_file.seek(0)
+      output_file.truncate()
       print('Retrying in %d s ...' % retry_wait_s)
       sys.stdout.flush()
       time.sleep(retry_wait_s)
@@ -181,8 +183,11 @@ def GetPlatformUrlPrefix(host_os):
   return CDS_URL + '/' + _HOST_OS_URL_MAP[host_os] + '/'
 
 
-def DownloadAndUnpackPackage(package_file, output_dir, host_os):
-  cds_file = "%s-%s.tgz" % (package_file, PACKAGE_VERSION)
+def DownloadAndUnpackPackage(package_file,
+                             output_dir,
+                             host_os,
+                             version=PACKAGE_VERSION):
+  cds_file = "%s-%s.tar.xz" % (package_file, version)
   cds_full_url = GetPlatformUrlPrefix(host_os) + cds_file
   try:
     DownloadAndUnpack(cds_full_url, output_dir)
@@ -194,7 +199,7 @@ def DownloadAndUnpackPackage(package_file, output_dir, host_os):
 
 
 def DownloadAndUnpackClangMacRuntime(output_dir):
-  cds_file = "clang-%s.tgz" % PACKAGE_VERSION
+  cds_file = "clang-%s.tar.xz" % PACKAGE_VERSION
   # We run this only for the runtime libraries, and 'mac' and 'mac-arm64' both
   # have the same (universal) runtime libraries. It doesn't matter which one
   # we download here.
@@ -213,7 +218,7 @@ def DownloadAndUnpackClangMacRuntime(output_dir):
 
 # TODO(hans): Create a clang-win-runtime package instead.
 def DownloadAndUnpackClangWinRuntime(output_dir):
-  cds_file = "clang-%s.tgz" % PACKAGE_VERSION
+  cds_file = "clang-%s.tar.xz" % PACKAGE_VERSION
   cds_full_url = GetPlatformUrlPrefix('win') + cds_file
   path_prefixes = [
       'lib/clang/' + RELEASE_VERSION + '/lib/windows', 'bin/llvm-symbolizer.exe'
diff --git a/chromium/tools/clang/scripts/upload_revision.py b/chromium/tools/clang/scripts/upload_revision.py
index 7386e5ac5ec..911ee36d0ba 100755
--- a/chromium/tools/clang/scripts/upload_revision.py
+++ b/chromium/tools/clang/scripts/upload_revision.py
@@ -39,6 +39,7 @@ Cq-Include-Trybots: chromium/try:linux_chromium_cfi_rel_ng
 Cq-Include-Trybots: chromium/try:linux_chromium_chromeos_msan_rel_ng
 Cq-Include-Trybots: chromium/try:linux_chromium_msan_rel_ng
 Cq-Include-Trybots: chromium/try:mac11-arm64-rel,mac_chromium_asan_rel_ng
+Cq-Include-Trybots: chromium/try:ios-catalyst
 Cq-Include-Trybots: chromium/try:win-asan,win7-rel
 Cq-Include-Trybots: chromium/try:android-official,fuchsia-official
 Cq-Include-Trybots: chromium/try:mac-official,linux-official