Export of internal Abseil changes

--
587e6db882749fa7faa12815e614afab04d218b9 by Derek Mauro <dmauro@google.com>:

Use attribute detection for other sanitizer related attributes

PiperOrigin-RevId: 324077073

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3ee55e4935b4235516b1fcac3c55945e510f7afc by Evan Brown <ezb@google.com>:

Simplify CordRepExternal allocation/deallocation.

I think this can save some memory when `Releaser` is empty and when on platforms where alignof(CordRepExternal) < (default `::operator new` alignment).

We no longer need the API requirement that alignof(Releaser) <= (default `::operator new` alignment).

Also remove another static_assert from a TODO in cord_internal.h and fix some warnings about calling std::move on a forwarding reference.

PiperOrigin-RevId: 324053720

--
9fc78436565eb3b204d4aa425ee3773354392f45 by Derek Mauro <dmauro@google.com>:

Use auto-detected sanitizer attributes for ASAN, MSAN, and TSAN builds

PiperOrigin-RevId: 323831461
GitOrigin-RevId: 587e6db882749fa7faa12815e614afab04d218b9
Change-Id: Ie0e4a2846d7f66988a2d81a5e50721b62fdb3d6d

7 files changed, 32 insertions, 48 deletions

diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index ad29bb0d..2c4887b3 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -415,6 +415,7 @@ cc_library(
     deps = [
         ":base",
         ":base_internal",
+        ":config",
         ":core_headers",
         "//absl/synchronization",
         "@com_google_googletest//:gtest",
@@ -431,6 +432,7 @@ cc_test(
     deps = [
         ":base",
         ":base_internal",
+        ":config",
         ":core_headers",
         "//absl/synchronization",
         "@com_google_googletest//:gtest_main",
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index f5cfc792..9ff5aa24 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -384,6 +384,7 @@ absl_cc_library(
     ${ABSL_TEST_COPTS}
   DEPS
     absl::base
+    absl::config
     absl::base_internal
     absl::core_headers
     absl::synchronization
@@ -402,6 +403,7 @@ absl_cc_test(
   DEPS
     absl::base
     absl::base_internal
+    absl::config
     absl::core_headers
     absl::synchronization
     gtest_main
diff --git a/absl/base/attributes.h b/absl/base/attributes.h
index 2cf4b1e8..046fbea3 100644
--- a/absl/base/attributes.h
+++ b/absl/base/attributes.h
@@ -32,34 +32,12 @@
 // of them are not supported in older version of Clang. Thus, we check
 // `__has_attribute()` first. If the check fails, we check if we are on GCC and
 // assume the attribute exists on GCC (which is verified on GCC 4.7).
-//
-// -----------------------------------------------------------------------------
-// Sanitizer Attributes
-// -----------------------------------------------------------------------------
-//
-// Sanitizer-related attributes are not "defined" in this file (and indeed
-// are not defined as such in any file). To utilize the following
-// sanitizer-related attributes within your builds, define the following macros
-// within your build using a `-D` flag, along with the given value for
-// `-fsanitize`:
-//
-//   * `ADDRESS_SANITIZER` + `-fsanitize=address` (Clang, GCC 4.8)
-//   * `MEMORY_SANITIZER` + `-fsanitize=memory` (Clang-only)
-//   * `THREAD_SANITIZER` + `-fsanitize=thread` (Clang, GCC 4.8+)
-//   * `UNDEFINED_BEHAVIOR_SANITIZER` + `-fsanitize=undefined` (Clang, GCC 4.9+)
-//   * `CONTROL_FLOW_INTEGRITY` + `-fsanitize=cfi` (Clang-only)
-//
-// Example:
-//
-//   // Enable branches in the Abseil code that are tagged for ASan:
-//   $ bazel build --copt=-DADDRESS_SANITIZER --copt=-fsanitize=address
-//     --linkopt=-fsanitize=address *target*
-//
-// Since these macro names are only supported by GCC and Clang, we only check
-// for `__GNUC__` (GCC or Clang) and the above macros.
+
 #ifndef ABSL_BASE_ATTRIBUTES_H_
 #define ABSL_BASE_ATTRIBUTES_H_
 
+#include "absl/base/config.h"
+
 // ABSL_HAVE_ATTRIBUTE
 //
 // A function-like feature checking macro that is a wrapper around
@@ -234,7 +212,7 @@
 // out of bounds or does other scary things with memory.
 // NOTE: GCC supports AddressSanitizer(asan) since 4.8.
 // https://gcc.gnu.org/gcc-4.8/changes.html
-#if defined(__GNUC__)
+#if ABSL_HAVE_ATTRIBUTE(no_sanitize_address)
 #define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
 #else
 #define ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS
@@ -242,13 +220,13 @@
 
 // ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY
 //
-// Tells the  MemorySanitizer to relax the handling of a given function. All
-// "Use of uninitialized value" warnings from such functions will be suppressed,
-// and all values loaded from memory will be considered fully initialized.
-// This attribute is similar to the ADDRESS_SANITIZER attribute above, but deals
-// with initialized-ness rather than addressability issues.
+// Tells the MemorySanitizer to relax the handling of a given function. All "Use
+// of uninitialized value" warnings from such functions will be suppressed, and
+// all values loaded from memory will be considered fully initialized.  This
+// attribute is similar to the ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS attribute
+// above, but deals with initialized-ness rather than addressability issues.
 // NOTE: MemorySanitizer(msan) is supported by Clang but not GCC.
-#if defined(__clang__)
+#if ABSL_HAVE_ATTRIBUTE(no_sanitize_memory)
 #define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
 #else
 #define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY
@@ -259,7 +237,7 @@
 // Tells the ThreadSanitizer to not instrument a given function.
 // NOTE: GCC supports ThreadSanitizer(tsan) since 4.8.
 // https://gcc.gnu.org/gcc-4.8/changes.html
-#if defined(__GNUC__)
+#if ABSL_HAVE_ATTRIBUTE(no_sanitize_thread)
 #define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
 #else
 #define ABSL_ATTRIBUTE_NO_SANITIZE_THREAD
@@ -271,8 +249,10 @@
 // where certain behavior (eg. division by zero) is being used intentionally.
 // NOTE: GCC supports UndefinedBehaviorSanitizer(ubsan) since 4.9.
 // https://gcc.gnu.org/gcc-4.9/changes.html
-#if defined(__GNUC__) && \
-    (defined(UNDEFINED_BEHAVIOR_SANITIZER) || defined(ADDRESS_SANITIZER))
+#if ABSL_HAVE_ATTRIBUTE(no_sanitize_undefined)
+#define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED \
+  __attribute__((no_sanitize_undefined))
+#elif ABSL_HAVE_ATTRIBUTE(no_sanitize)
 #define ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED \
   __attribute__((no_sanitize("undefined")))
 #else
@@ -283,7 +263,7 @@
 //
 // Tells the ControlFlowIntegrity sanitizer to not instrument a given function.
 // See https://clang.llvm.org/docs/ControlFlowIntegrity.html for details.
-#if defined(__GNUC__) && defined(CONTROL_FLOW_INTEGRITY)
+#if ABSL_HAVE_ATTRIBUTE(no_sanitize)
 #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI __attribute__((no_sanitize("cfi")))
 #else
 #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI
@@ -293,7 +273,7 @@
 //
 // Tells the SafeStack to not instrument a given function.
 // See https://clang.llvm.org/docs/SafeStack.html for details.
-#if defined(__GNUC__) && defined(SAFESTACK_SANITIZER)
+#if ABSL_HAVE_ATTRIBUTE(no_sanitize)
 #define ABSL_ATTRIBUTE_NO_SANITIZE_SAFESTACK \
   __attribute__((no_sanitize("safe-stack")))
 #else
diff --git a/absl/base/internal/dynamic_annotations.h b/absl/base/internal/dynamic_annotations.h
index 7d80f41c..b69c1301 100644
--- a/absl/base/internal/dynamic_annotations.h
+++ b/absl/base/internal/dynamic_annotations.h
@@ -91,12 +91,9 @@
 #endif
 
 // Memory annotations are also made available to LLVM's Memory Sanitizer
-#if defined(MEMORY_SANITIZER) && defined(__has_feature) && \
-    !defined(__native_client__)
-#if __has_feature(memory_sanitizer)
+#if defined(ABSL_HAVE_MEMORY_SANITIZER) && !defined(__native_client__)
 #define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 1
 #endif
-#endif
 
 #ifndef ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED
 #define ABSL_INTERNAL_MEMORY_ANNOTATIONS_ENABLED 0
@@ -162,7 +159,7 @@
   ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreate)(__FILE__, __LINE__, lock)
 
 // Report that a linker initialized lock has been created at address `lock`.
-#ifdef THREAD_SANITIZER
+#ifdef ABSL_HAVE_THREAD_SANITIZER
 #define ANNOTATE_RWLOCK_CREATE_STATIC(lock)               \
   ABSL_INTERNAL_GLOBAL_SCOPED(AnnotateRWLockCreateStatic) \
   (__FILE__, __LINE__, lock)
@@ -367,7 +364,7 @@
 // -------------------------------------------------------------------------
 // Address sanitizer annotations
 
-#ifdef ADDRESS_SANITIZER
+#ifdef ABSL_HAVE_ADDRESS_SANITIZER
 // Describe the current state of a contiguous container such as e.g.
 // std::vector or std::string. For more details see
 // sanitizer/common_interface_defs.h, which is provided by the compiler.
@@ -385,7 +382,7 @@
 #define ANNOTATE_CONTIGUOUS_CONTAINER(beg, end, old_mid, new_mid)
 #define ADDRESS_SANITIZER_REDZONE(name) static_assert(true, "")
 
-#endif  // ADDRESS_SANITIZER
+#endif  // ABSL_HAVE_ADDRESS_SANITIZER
 
 // -------------------------------------------------------------------------
 // Undefine the macros intended only for this file.
diff --git a/absl/base/internal/tsan_mutex_interface.h b/absl/base/internal/tsan_mutex_interface.h
index 2a510603..39207d8a 100644
--- a/absl/base/internal/tsan_mutex_interface.h
+++ b/absl/base/internal/tsan_mutex_interface.h
@@ -19,6 +19,8 @@
 #ifndef ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_
 #define ABSL_BASE_INTERNAL_TSAN_MUTEX_INTERFACE_H_
 
+#include "absl/base/config.h"
+
 // ABSL_INTERNAL_HAVE_TSAN_INTERFACE
 // Macro intended only for internal use.
 //
@@ -28,7 +30,7 @@
 #error "ABSL_INTERNAL_HAVE_TSAN_INTERFACE cannot be directly set."
 #endif
 
-#if defined(THREAD_SANITIZER) && defined(__has_include)
+#if defined(ABSL_HAVE_THREAD_SANITIZER) && defined(__has_include)
 #if __has_include(<sanitizer/tsan_interface.h>)
 #define ABSL_INTERNAL_HAVE_TSAN_INTERFACE 1
 #endif
diff --git a/absl/base/internal/unaligned_access.h b/absl/base/internal/unaligned_access.h
index 6be56c86..dd5250de 100644
--- a/absl/base/internal/unaligned_access.h
+++ b/absl/base/internal/unaligned_access.h
@@ -32,8 +32,8 @@
 // (namespaces, inline) which are absent or incompatible in C.
 #if defined(__cplusplus)
 
-#if defined(ADDRESS_SANITIZER) || defined(THREAD_SANITIZER) ||\
-    defined(MEMORY_SANITIZER)
+#if defined(ABSL_HAVE_ADDRESS_SANITIZER) || \
+    defined(ABSL_HAVE_THREAD_SANITIZER) || defined(ABSL_HAVE_MEMORY_SANITIZER)
 // Consider we have an unaligned load/store of 4 bytes from address 0x...05.
 // AddressSanitizer will treat it as a 3-byte access to the range 05:07 and
 // will miss a bug if 08 is the first unaddressable byte.
diff --git a/absl/base/spinlock_test_common.cc b/absl/base/spinlock_test_common.cc
index b33c54ba..dee266e4 100644
--- a/absl/base/spinlock_test_common.cc
+++ b/absl/base/spinlock_test_common.cc
@@ -25,6 +25,7 @@
 
 #include "gtest/gtest.h"
 #include "absl/base/attributes.h"
+#include "absl/base/config.h"
 #include "absl/base/internal/low_level_scheduling.h"
 #include "absl/base/internal/scheduling_mode.h"
 #include "absl/base/internal/spinlock.h"
@@ -104,7 +105,7 @@ static void ThreadedTest(SpinLock* spinlock) {
   }
 }
 
-#ifndef THREAD_SANITIZER
+#ifndef ABSL_HAVE_THREAD_SANITIZER
 static_assert(std::is_trivially_destructible<SpinLock>(), "");
 #endif