Revert "Roll clang 365097:368742."

This reverts commit 8b43f27.

Reason for revert: Causing crashes in ANGLE's dEQP tests. Likely
related to exception handling on Windows.

See issue for more details.

Bug: 994333

Original change's description:
> Roll clang 365097:368742.
> 
> Extra changes in this update:
> - Update the released clang version to 10.0.0.
> 
> - Move -momit-leaf-frame-pointer next to -fno-omit-frame-pointer
>   since that's where it logically belongs. clang started warning
>   on momit without fno-omit after r365860, but it stopped doing this
>   again in r368728 so this change is no longer needed for the roll.
>   But it's still a nice cleanup.
> 
> - A file in the profile runtime with static init was renamed, do that in the
>   check
> 
> - Disable new -Wno-implicit-float-conversion warning
> 
> - Remove ifdefs for plugins using new ErrorOr API in clang
> 
> - Remove -Wno-error=return-stack-address flag for ToT builds.
> 
> TBR=dpranke
> 
> Binary-Size: crbug.com/992372, compiler update adds 32KB, seems reasonable
> Bug: 983371
> Change-Id: Id6e64948fe4966b486aa77615e19f4f7566f13ed
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1751203
> Commit-Queue: Hans Wennborg <hans@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#686837}

TBR=thakis@chromium.org,hans@chromium.org

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

Bug: 983371
Change-Id: I3e577f9bb0e8c42e29b06b7580fadc80a0529f2c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1756767
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#687472}

build/config/compiler/BUILD.gn

@@ -1052,6 +1052,16 @@ config("compiler_codegen") {
 
   if (is_nacl) {
     configs += [ "//build/config/nacl:compiler_codegen" ]
+  } else if (is_posix && !is_mac && !is_ios) {
+    if (current_cpu == "x86") {
+      if (is_clang) {
+        cflags += [
+          # Else building libyuv gives clang's register allocator issues,
+          # see llvm.org/PR15798 / crbug.com/233709
+          "-momit-leaf-frame-pointer",
+        ]
+      }
+    }
   }
 
   if (current_cpu == "arm64" && is_android) {
@@ -1508,10 +1518,21 @@ config("default_warnings") {
           # Ignore warnings about MSVC optimization pragmas.
           # TODO(thakis): Only for no_chromium_code? http://crbug.com/912662
           "-Wno-ignored-pragma-optimize",
-
-          # TODO(https://crbug.com/989932): Evaluate and possibly enable.
-          "-Wno-implicit-int-float-conversion",
         ]
+        if (llvm_force_head_revision) {
+          cflags += [
+            # TODO(https://crbug.com/989932): Evaluate and possibly enable.
+            "-Wno-implicit-int-float-conversion",
+
+            # TODO(https://crbug.com/992458): Fix and re-enable. When rolling
+            # past clang r368446, do *not* move this out of
+            # llvm_force_head_revision -- we need to fix all instances before
+            # rolling, else we lose a valuable pre-existing warning that got
+            # smarter on clang trunk. (And having a -Wno-error flag instead of
+            # -Wno-return-stack-address on pinned clang won't fly either.)
+            "-Wno-error=return-stack-address",
+          ]
+        }
       }
     }
   }
@@ -1938,13 +1959,6 @@ config("default_stack_frames") {
   if (is_posix || is_fuchsia) {
     if (enable_frame_pointers) {
       cflags = [ "-fno-omit-frame-pointer" ]
-
-      # Omit frame pointers for leaf functions on x86, otherwise building libyuv
-      # gives clang's register allocator issues, see llvm.org/PR15798 /
-      # crbug.com/233709
-      if (is_clang && current_cpu == "x86" && !is_mac && !is_ios) {
-        cflags += [ "-momit-leaf-frame-pointer" ]
-      }
     } else {
       cflags = [ "-fomit-frame-pointer" ]
     }

build/nocompile.gni

@@ -101,10 +101,11 @@ if (enable_nocompile_tests) {
         "-Wthread-safety",
         "-I" + rebase_path("//", root_build_dir),
         "-I" + rebase_path(root_gen_dir, root_build_dir),
-
-        # TODO(https://crbug.com/989932): Track build/config/compiler/BUILD.gn
-        "-Wno-implicit-int-float-conversion",
       ]
+      if (llvm_force_head_revision) {
+        # TODO(https://crbug.com/989932): Track build/config/compiler/BUILD.gn
+        args += [ "-Wno-implicit-int-float-conversion" ]
+      }
       if (sysroot != "") {
         args += [
           "--sysroot",

build/toolchain/toolchain.gni

@@ -37,7 +37,12 @@ if (generate_linker_map) {
 declare_args() {
   if (is_clang) {
     # Clang compiler version. Clang files are placed at version-dependent paths.
-    clang_version = "10.0.0"
+    if (llvm_force_head_revision) {
+      clang_version = "10.0.0"
+    } else {
+      # TODO(crbug.com/985289): Remove after rolling past r366427.
+      clang_version = "9.0.0"
+    }
   }
 }
 

testing/scripts/check_static_initializers.py

@@ -16,7 +16,7 @@
 # in static initializers.
 _LINUX_SI_FILE_WHITELIST = {
     'chrome': [
-        'InstrProfilingRuntime.cpp',  # Only in coverage builds, not production.
+        'InstrProfilingRuntime.cc',  # Only in coverage builds, not production.
         'atomicops_internals_x86.cc',  # TODO(crbug.com/973551): Remove.
         'debugallocation_shim.cc',  # TODO(crbug.com/973552): Remove.
         'iostream.cpp',  # TODO(crbug.com/973554): Remove.

tools/clang/scripts/build.py

@@ -338,6 +338,15 @@ def main():
                       default=sys.platform in ('linux2', 'darwin'))
   args = parser.parse_args()
 
+  # TODO(crbug.com/985289): Remove when rolling past r366427.
+  if args.llvm_force_head_revision:
+    global RELEASE_VERSION
+    RELEASE_VERSION = '10.0.0'
+    old_lib_dir = os.path.join(LLVM_BUILD_DIR, 'lib', 'clang', '9.0.0')
+    if (os.path.isdir(old_lib_dir)):
+      print('Removing old lib dir: ' + old_lib_dir)
+      RmTree(old_lib_dir)
+
   if args.lto_lld and not args.bootstrap:
     print('--lto-lld requires --bootstrap')
     return 1

tools/clang/scripts/update.py

@@ -37,13 +37,14 @@
 # Do NOT CHANGE this if you don't know what you're doing -- see
 # https://chromium.googlesource.com/chromium/src/+/master/docs/updating_clang.md
 # Reverting problematic clang rolls is safe, though.
-CLANG_REVISION = '235339357d3c2cf454e59a994686b45f8190671f'
-CLANG_SVN_REVISION = '368742'
-CLANG_SUB_REVISION = 1
+CLANG_REVISION = 'f7e52fbdb5a7af8ea0808e98458b497125a5eca1'
+CLANG_SVN_REVISION = '365097'
+CLANG_SUB_REVISION = 8
 
 PACKAGE_VERSION = '%s-%s-%s' % (CLANG_SVN_REVISION, CLANG_REVISION[:8],
                                 CLANG_SUB_REVISION)
-RELEASE_VERSION = '10.0.0'
+# TODO(crbug.com/985289): Bump when rolling past r366427.
+RELEASE_VERSION = '9.0.0'
 
 
 CDS_URL = os.environ.get('CDS_CLANG_BUCKET_OVERRIDE',
@@ -293,6 +294,11 @@ def main():
                       help='Verify that clang has the passed-in version.')
   args = parser.parse_args()
 
+  # TODO(crbug.com/985289): Remove when rolling past r366427.
+  if args.llvm_force_head_revision:
+    global RELEASE_VERSION
+    RELEASE_VERSION = '10.0.0'
+
   if args.force_local_build:
     print(('update.py --force-local-build is no longer used to build clang; '
            'use build.py instead.'))

tools/clang/translation_unit/TranslationUnitGenerator.cpp

@@ -168,11 +168,20 @@ void IncludeFinderPPCallbacks::InclusionDirective(
     return;
 
   assert(!current_files_.top().empty());
+#ifdef LLVM_FORCE_HEAD_REVISION
   const clang::DirectoryEntry* const search_path_entry = getValueOrNull(
       source_manager_->getFileManager().getDirectory(search_path));
   const clang::DirectoryEntry* const current_file_parent_entry =
       (*source_manager_->getFileManager().getFile(current_files_.top().c_str()))
           ->getDir();
+#else
+  const clang::DirectoryEntry* const search_path_entry =
+      source_manager_->getFileManager().getDirectory(search_path);
+  const clang::DirectoryEntry* const current_file_parent_entry =
+      source_manager_->getFileManager()
+          .getFile(current_files_.top().c_str())
+          ->getDir();
+#endif
 
   // If the include file was found relatively to the current file's parent
   // directory or a search path, we need to normalize it. This is necessary