Changes imported from Abseil "staging" branch:

  - b527a3e4b36b644ac424e3c525b1cd393f6f6c40 Fix some typos in the usage examples by Jorg Brown <jorg@google.com>
  - 82be4a9adf3bb0ddafc0d46274969c99afffe870 Fix typo in optional.h comment. by Abseil Team <absl-team@google.com>
  - d6ee63bf8fc51fba074c23b33cebc28c808d7f07 Remove internal-only identifiers from code. by Daniel Katz <katzdm@google.com>
  - f9c3ad2f0d73f53b21603638af8b4bed636e79f4 Use easier understandable names for absl::StartsWith and ... by Abseil Team <absl-team@google.com>
  - 7c16c14fefee89c927b8789d6043c4691bcffc9b Add -Wno-missing-prototypes back to the LLVM copts. by Derek Mauro <dmauro@google.com>
  - 2f4b7d2e50c7023240242f1e15db60ccd7e8768d IWYU | absl/strings by Juemin Yang <jueminyang@google.com>
  - a99cbcc1daa34a2d6a2bb26de275e05173cc77e9 IWYU | absl/type by Juemin Yang <jueminyang@google.com>
  - 12e1146d0fc76c071d7e0ebaabb62f0a984fae66 Use LLVM_FLAGS and LLVM_TEST_FLAGS when --compiler=llvm. by Derek Mauro <dmauro@google.com>
  - cd6bea616abda558d0bace5bd77455662a233688 IWYU | absl/debugging by Juemin Yang <jueminyang@google.com>
  - d9a7382e59d46a8581b6b7a31cd5a48bb89326e9 IWYU | absl/synchronization by Juemin Yang <jueminyang@google.com>
  - 07ec7d6d5a4a666f4183c5d0ed9c342baa7b24bc IWYU | absl/numeric by Juemin Yang <jueminyang@google.com>
  - 12bfe40051f4270f8707e191af5652f83f2f750c Remove the RoundTrip{Float,Double}ToBuffer routines from ... by Jorg Brown <jorg@google.com>
  - eeb4fd67c9d97f66cb9475c3c5e51ab132f1c810 Adds conversion functions for converting between absl/tim... by Greg Miller <jgm@google.com>
  - 59a2108d05d4ea85dc5cc11e49b2cd2335d4295a Change Substitute to use %.6g formatting rather than 15/1... by Jorg Brown <jorg@google.com>
  - 394becb48e0fcd161642cdaac5120d32567e0ef8 IWYU | absl/meta by Juemin Yang <jueminyang@google.com>
  - 1e5da6e8da336699b2469dcf6dda025b9b0ec4c9 Rewrite atomic_hook.h to not use std::atomic<T*> under Wi... by Greg Falcon <gfalcon@google.com>

GitOrigin-RevId: b527a3e4b36b644ac424e3c525b1cd393f6f6c40
Change-Id: I14e331d91c956ef045ac7927091a9f179716de0c

3 files changed, 3 insertions, 134 deletions

diff --git a/absl/debugging/internal/address_is_readable.cc b/absl/debugging/internal/address_is_readable.cc
index 037ea54c..30d2e71d 100644
--- a/absl/debugging/internal/address_is_readable.cc
+++ b/absl/debugging/internal/address_is_readable.cc
@@ -33,7 +33,6 @@ bool AddressIsReadable(const void* /* addr */) { return true; }
 #include <fcntl.h>
 #include <sys/syscall.h>
 #include <unistd.h>
-
 #include <atomic>
 #include <cerrno>
 #include <cstdint>
diff --git a/absl/debugging/internal/stacktrace_config.h b/absl/debugging/internal/stacktrace_config.h
index c0df5bb0..57f0b0f2 100644
--- a/absl/debugging/internal/stacktrace_config.h
+++ b/absl/debugging/internal/stacktrace_config.h
@@ -25,15 +25,13 @@
 #if ABSL_STACKTRACE_INL_HEADER
 #error ABSL_STACKTRACE_INL_HEADER cannot be directly set
 #elif defined(__native_client__) || defined(__APPLE__) || \
-    defined(__ANDROID__) || defined(__myriad2__) || defined(__asmjs__) || \
-    defined(__Fuchsia__) || defined(__GENCLAVE__) || \
-    defined(GOOGLE_UNSUPPORTED_OS_HERCULES)
+    defined(__ANDROID__) || defined(__myriad2__) || defined(asmjs__) || \
+    defined(__Fuchsia__)
 #define ABSL_STACKTRACE_INL_HEADER \
     "absl/debugging/internal/stacktrace_unimplemented-inl.inc"
 
 // Next, test for Mips and Windows.
-// TODO(marmstrong): http://b/21334018: Mips case, remove the check for
-// ABSL_STACKTRACE_INL_HEADER.
+// TODO(marmstrong): Mips case, remove the check for ABSL_STACKTRACE_INL_HEADER
 #elif defined(__mips__) && !defined(ABSL_STACKTRACE_INL_HEADER)
 #define ABSL_STACKTRACE_INL_HEADER \
     "absl/debugging/internal/stacktrace_unimplemented-inl.inc"
diff --git a/absl/debugging/internal/stacktrace_libunwind-inl.inc b/absl/debugging/internal/stacktrace_libunwind-inl.inc
deleted file mode 100644
index e9c2d26a..00000000
--- a/absl/debugging/internal/stacktrace_libunwind-inl.inc
+++ /dev/null
@@ -1,128 +0,0 @@
-// 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_DEBUGGING_INTERNAL_STACKTRACE_LIBUNWIND_INL_H_
-#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_LIBUNWIND_INL_H_
-
-// We only need local unwinder.
-#define UNW_LOCAL_ONLY
-
-extern "C" {
-#include "third_party/libunwind/include/libunwind.h"
-}
-#include "absl/debugging/stacktrace.h"
-
-#include "absl/base/dynamic_annotations.h"
-#include "absl/base/internal/raw_logging.h"
-
-// Sometimes, we can try to get a stack trace from within a stack
-// trace, because we don't block signals inside libunwind (which would be too
-// expensive: the two extra system calls per stack trace do matter here).
-// That can cause a self-deadlock (as in http://b/5722312).
-// Protect against such reentrant call by failing to get a stack trace.
-//
-// We use __thread here because the code here is extremely low level -- it is
-// called while collecting stack traces from within malloc and mmap, and thus
-// can not call anything which might call malloc or mmap itself.
-// In particular, using PerThread or STATIC_THREAD_LOCAL_POD
-// here will cause infinite recursion for at least dbg/piii builds with
-// crosstool-v12.
-static __thread int recursive;
-
-template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
-static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
-                      const void *, int *min_dropped_frames) {
-  if (recursive) {
-    return 0;
-  }
-  ++recursive;
-
-  int n = 0;
-  if (IS_STACK_FRAMES) {
-    void *ip;
-    unw_cursor_t cursor;
-    unw_context_t uc;
-    unw_word_t sp = 0, next_sp = 0;
-
-    unw_getcontext(&uc);
-    ABSL_RAW_CHECK(unw_init_local(&cursor, &uc) >= 0, "unw_init_local failed");
-    skip_count++;         // Do not include current frame
-
-    while (skip_count--) {
-      if (unw_step(&cursor) <= 0) {
-        goto out;
-      }
-      if (unw_get_reg(&cursor, UNW_REG_SP, &next_sp)) {
-        goto out;
-      }
-    }
-
-    while (n < max_depth) {
-      if (unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip) < 0) {
-        break;
-      }
-      sizes[n] = 0;
-      result[n++] = ip;
-      if (unw_step(&cursor) <= 0) {
-        break;
-      }
-      sp = next_sp;
-      if (unw_get_reg(&cursor, UNW_REG_SP, &next_sp) , 0) {
-        break;
-      }
-      sizes[n - 1] = next_sp - sp;
-    }
-    if (min_dropped_frames != nullptr) {
-      // Implementation detail: we clamp the max of frames we are willing to
-      // count, so as not to spend too much time in the loop below.
-      const int kMaxUnwind = 200;
-      int j = 0;
-      for (; j < kMaxUnwind; j++) {
-        if (unw_step(&cursor) < 0) {
-          break;
-        }
-      }
-      *min_dropped_frames = j;
-    }
-  } else {
-    skip_count++;  // Do not include current frame.
-    void **result_all = reinterpret_cast<void**>(
-        alloca(sizeof(void*) * (max_depth + skip_count)));
-    int rc = unw_backtrace(result_all, max_depth + skip_count);
-
-    if (rc > 0) {
-      // Tell MSan that result_all has been initialized. b/34965936.
-      ANNOTATE_MEMORY_IS_INITIALIZED(result_all, rc * sizeof(void*));
-    }
-
-    if (rc > skip_count) {
-      memcpy(result, &result_all[skip_count],
-             sizeof(void*) * (rc - skip_count));
-      n = rc - skip_count;
-    } else {
-      n = 0;
-    }
-
-    if (min_dropped_frames != nullptr) {
-      // Not implemented.
-      *min_dropped_frames = 0;
-    }
-  }
-
- out:
-  --recursive;
-  return n;
-}
-
-#endif  // ABSL_DEBUGGING_INTERNAL_STACKTRACE_LIBUNWIND_INL_H_