Changes imported from Abseil "staging" branch:

  - 20f4e7133d695e9a05e13ebdfd4d78da310b42b5 Remove the warning supressions -Wno-documentation and by Derek Mauro <dmauro@google.com>
  - e1bde85c0571673b1e7a88b9d45a393606ba7e6c Changed the optimized version of strings_internal::JoinAl... by Abseil Team <absl-team@google.com>
  - 746e6716b4c15be61547670d68d25a1c850d3954 Add missing absl:: qualification. by Alex Strelnikov <strel@google.com>
  - 4e5c18c488cbd49ca72b02911cf22d830d5a7f16 Internals change: Remove the ability to pass a custom met... by Greg Falcon <gfalcon@google.com>
  - 65d58107a5730d4b6468bbffc72bea2f980af826 Moved most common character case (ascii printable) out of... by Abseil Team <absl-team@google.com>
  - f031331cc55a3d57b9110e12c7cbe50ac3e2a04f Add missing copyright headers to a few source files. by Greg Falcon <gfalcon@google.com>
  - 6035a77af6fa951c536b42df4c710d16d1817aec Enable libstdc++'s memcmp optimization in absl::equal for... by Abseil Team <absl-team@google.com>
  - 73a665a4a10781e5d89f75a876ece7ad859f4116 Fix minor spelling error "hexidecimal". by Abseil Team <absl-team@google.com>

GitOrigin-RevId: 20f4e7133d695e9a05e13ebdfd4d78da310b42b5
Change-Id: Id8c18ebd331d096935052a6ab259ebe0e2ef13ae

8 files changed, 83 insertions, 19 deletions

diff --git a/absl/base/exception_safety_testing_test.cc b/absl/base/exception_safety_testing_test.cc
index 20cbb435926a..1fc03861784e 100644
--- a/absl/base/exception_safety_testing_test.cc
+++ b/absl/base/exception_safety_testing_test.cc
@@ -1,3 +1,17 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 #include "absl/base/internal/exception_safety_testing.h"
 
 #include <cstddef>
diff --git a/absl/base/internal/exception_safety_testing.cc b/absl/base/internal/exception_safety_testing.cc
index 32d904ed23fa..ab8d6c9fb4d0 100644
--- a/absl/base/internal/exception_safety_testing.cc
+++ b/absl/base/internal/exception_safety_testing.cc
@@ -1,3 +1,17 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 #include "absl/base/internal/exception_safety_testing.h"
 
 #include "gtest/gtest.h"
diff --git a/absl/base/internal/exception_safety_testing.h b/absl/base/internal/exception_safety_testing.h
index 05bcd0ab59d6..a0127a8819fa 100644
--- a/absl/base/internal/exception_safety_testing.h
+++ b/absl/base/internal/exception_safety_testing.h
@@ -1,3 +1,17 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 // Utilities for testing exception-safety
 
 #ifndef ABSL_BASE_INTERNAL_EXCEPTION_SAFETY_TESTING_H_
diff --git a/absl/base/internal/exception_testing.h b/absl/base/internal/exception_testing.h
index 99a10734842b..07d7e8ee1ba6 100644
--- a/absl/base/internal/exception_testing.h
+++ b/absl/base/internal/exception_testing.h
@@ -1,3 +1,17 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 // Testing utilities for ABSL types which throw exceptions.
 
 #ifndef ABSL_BASE_INTERNAL_EXCEPTION_TESTING_H_
diff --git a/absl/base/internal/low_level_alloc.cc b/absl/base/internal/low_level_alloc.cc
index 962232433665..5f047a54389a 100644
--- a/absl/base/internal/low_level_alloc.cc
+++ b/absl/base/internal/low_level_alloc.cc
@@ -358,18 +358,15 @@ LowLevelAlloc::Arena::Arena(uint32_t flags_value)
 }
 
 // L < meta_data_arena->mu
-LowLevelAlloc::Arena *LowLevelAlloc::NewArena(int32_t flags,
-                                              Arena *meta_data_arena) {
-  ABSL_RAW_CHECK(meta_data_arena != nullptr, "must pass a valid arena");
-  if (meta_data_arena == DefaultArena()) {
+LowLevelAlloc::Arena *LowLevelAlloc::NewArena(int32_t flags) {
+  Arena *meta_data_arena = DefaultArena();
 #ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
-    if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
-      meta_data_arena = UnhookedAsyncSigSafeArena();
-    } else  // NOLINT(readability/braces)
+  if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
+    meta_data_arena = UnhookedAsyncSigSafeArena();
+  } else  // NOLINT(readability/braces)
 #endif
-        if ((flags & LowLevelAlloc::kCallMallocHook) == 0) {
-      meta_data_arena = UnhookedArena();
-    }
+      if ((flags & LowLevelAlloc::kCallMallocHook) == 0) {
+    meta_data_arena = UnhookedArena();
   }
   Arena *result =
     new (AllocWithArena(sizeof (*result), meta_data_arena)) Arena(flags);
diff --git a/absl/base/internal/low_level_alloc.h b/absl/base/internal/low_level_alloc.h
index f3e8aa57f94f..3c15605bed35 100644
--- a/absl/base/internal/low_level_alloc.h
+++ b/absl/base/internal/low_level_alloc.h
@@ -93,15 +93,12 @@ class LowLevelAlloc {
     // DefaultArena(). Not supported on all platforms.
     kAsyncSignalSafe = 0x0002,
 #endif
-
-    // When used with DefaultArena(), the NewArena() and DeleteArena() calls
-    // obey the flags given explicitly in the NewArena() call, even if those
-    // flags differ from the settings in DefaultArena().  So the call
-    // NewArena(kAsyncSignalSafe, DefaultArena()) is itself async-signal-safe,
-    // as well as generatating an arena that provides async-signal-safe
-    // Alloc/Free.
   };
-  static Arena *NewArena(int32_t flags, Arena *meta_data_arena);
+  // Construct a new arena.  The allocation of the underlying metadata honors
+  // the provided flags.  For example, the call NewArena(kAsyncSignalSafe)
+  // is itself async-signal-safe, as well as generatating an arena that provides
+  // async-signal-safe Alloc/Free.
+  static Arena *NewArena(int32_t flags);
 
   // Destroys an arena allocated by NewArena and returns true,
   // provided no allocated blocks remain in the arena.
diff --git a/absl/base/internal/low_level_alloc_test.cc b/absl/base/internal/low_level_alloc_test.cc
index 2935760dad53..7c359f306115 100644
--- a/absl/base/internal/low_level_alloc_test.cc
+++ b/absl/base/internal/low_level_alloc_test.cc
@@ -84,7 +84,7 @@ static void Test(bool use_new_arena, bool call_malloc_hook, int n) {
   LowLevelAlloc::Arena *arena = 0;
   if (use_new_arena) {
     int32_t flags = call_malloc_hook ? LowLevelAlloc::kCallMallocHook : 0;
-    arena = LowLevelAlloc::NewArena(flags, LowLevelAlloc::DefaultArena());
+    arena = LowLevelAlloc::NewArena(flags);
   }
   for (int i = 0; i != n; i++) {
     if (i != 0 && i % 10000 == 0) {
diff --git a/absl/base/internal/pretty_function.h b/absl/base/internal/pretty_function.h
index 6be3936f7c24..01b0547bd08a 100644
--- a/absl/base/internal/pretty_function.h
+++ b/absl/base/internal/pretty_function.h
@@ -1,3 +1,17 @@
+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 #ifndef ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_
 #define ABSL_BASE_INTERNAL_PRETTY_FUNCTION_H_