Change absl::Status implementation to be amenable to [[clang:trivial_abi]] annotation.

This moves the implementation of most methods from absl::Status to absl::status_internal::StatusRep, and ensures that no calls to absl::Status methods are in a cc file.

Stub implementations checking only inlined rep properties and calling no-op (RepToPointer) or out of line methods exist in status.h

PiperOrigin-RevId: 566187430
Change-Id: I356ec29c0970ffe82eac2a5d98850e647fcd5ea5

6 files changed, 376 insertions, 281 deletions

diff --git a/absl/status/BUILD.bazel b/absl/status/BUILD.bazel
index 6a6fb299..5be5c218 100644
--- a/absl/status/BUILD.bazel
+++ b/absl/status/BUILD.bazel
@@ -31,6 +31,7 @@ licenses(["notice"])
 cc_library(
     name = "status",
     srcs = [
+        "internal/status_internal.cc",
         "internal/status_internal.h",
         "status.cc",
         "status_payload_printer.cc",
diff --git a/absl/status/CMakeLists.txt b/absl/status/CMakeLists.txt
index ed2e3848..f369e341 100644
--- a/absl/status/CMakeLists.txt
+++ b/absl/status/CMakeLists.txt
@@ -20,6 +20,7 @@ absl_cc_library(
     "status.h"
   SRCS
     "internal/status_internal.h"
+    "internal/status_internal.cc"
     "status.cc"
     "status_payload_printer.h"
     "status_payload_printer.cc"
diff --git a/absl/status/internal/status_internal.cc b/absl/status/internal/status_internal.cc
new file mode 100644
index 00000000..2307579b
--- /dev/null
+++ b/absl/status/internal/status_internal.cc
@@ -0,0 +1,246 @@
+// Copyright 2023 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
+//
+//     https://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/status/internal/status_internal.h"
+
+#include <atomic>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstring>
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "absl/base/attributes.h"
+#include "absl/base/config.h"
+#include "absl/base/macros.h"
+#include "absl/debugging/stacktrace.h"
+#include "absl/debugging/symbolize.h"
+#include "absl/memory/memory.h"
+#include "absl/status/status.h"
+#include "absl/status/status_payload_printer.h"
+#include "absl/strings/cord.h"
+#include "absl/strings/escaping.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_split.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace status_internal {
+
+void StatusRep::Unref() const {
+  // Fast path: if ref==1, there is no need for a RefCountDec (since
+  // this is the only reference and therefore no other thread is
+  // allowed to be mucking with r).
+  if (ref_.load(std::memory_order_acquire) == 1 ||
+      ref_.fetch_sub(1, std::memory_order_acq_rel) - 1 == 0) {
+    delete this;
+  }
+}
+
+static absl::optional<size_t> FindPayloadIndexByUrl(
+    const Payloads* payloads, absl::string_view type_url) {
+  if (payloads == nullptr) return absl::nullopt;
+
+  for (size_t i = 0; i < payloads->size(); ++i) {
+    if ((*payloads)[i].type_url == type_url) return i;
+  }
+
+  return absl::nullopt;
+}
+
+absl::optional<absl::Cord> StatusRep::GetPayload(
+    absl::string_view type_url) const {
+  absl::optional<size_t> index =
+      status_internal::FindPayloadIndexByUrl(payloads_.get(), type_url);
+  if (index.has_value()) return (*payloads_)[index.value()].payload;
+
+  return absl::nullopt;
+}
+
+void StatusRep::SetPayload(absl::string_view type_url, absl::Cord payload) {
+  if (payloads_ == nullptr) {
+    payloads_ = absl::make_unique<status_internal::Payloads>();
+  }
+
+  absl::optional<size_t> index =
+      status_internal::FindPayloadIndexByUrl(payloads_.get(), type_url);
+  if (index.has_value()) {
+    (*payloads_)[index.value()].payload = std::move(payload);
+    return;
+  }
+
+  payloads_->push_back({std::string(type_url), std::move(payload)});
+}
+
+StatusRep::EraseResult StatusRep::ErasePayload(absl::string_view type_url) {
+  absl::optional<size_t> index =
+      status_internal::FindPayloadIndexByUrl(payloads_.get(), type_url);
+  if (!index.has_value()) return {false, Status::PointerToRep(this)};
+  payloads_->erase(payloads_->begin() + index.value());
+  if (payloads_->empty() && message_.empty()) {
+    // Special case: If this can be represented inlined, it MUST be inlined
+    // (== depends on this behavior).
+    EraseResult result = {true, Status::CodeToInlinedRep(code_)};
+    Unref();
+    return result;
+  }
+  return {true, Status::PointerToRep(this)};
+}
+
+void StatusRep::ForEachPayload(
+    absl::FunctionRef<void(absl::string_view, const absl::Cord&)> visitor)
+    const {
+  if (auto* payloads = payloads_.get()) {
+    bool in_reverse =
+        payloads->size() > 1 && reinterpret_cast<uintptr_t>(payloads) % 13 > 6;
+
+    for (size_t index = 0; index < payloads->size(); ++index) {
+      const auto& elem =
+          (*payloads)[in_reverse ? payloads->size() - 1 - index : index];
+
+#ifdef NDEBUG
+      visitor(elem.type_url, elem.payload);
+#else
+      // In debug mode invalidate the type url to prevent users from relying on
+      // this string lifetime.
+
+      // NOLINTNEXTLINE intentional extra conversion to force temporary.
+      visitor(std::string(elem.type_url), elem.payload);
+#endif  // NDEBUG
+    }
+  }
+}
+
+std::string StatusRep::ToString(StatusToStringMode mode) const {
+  std::string text;
+  absl::StrAppend(&text, absl::StatusCodeToString(code()), ": ", message());
+
+  const bool with_payload = (mode & StatusToStringMode::kWithPayload) ==
+                            StatusToStringMode::kWithPayload;
+
+  if (with_payload) {
+    status_internal::StatusPayloadPrinter printer =
+        status_internal::GetStatusPayloadPrinter();
+    this->ForEachPayload([&](absl::string_view type_url,
+                             const absl::Cord& payload) {
+      absl::optional<std::string> result;
+      if (printer) result = printer(type_url, payload);
+      absl::StrAppend(
+          &text, " [", type_url, "='",
+          result.has_value() ? *result : absl::CHexEscape(std::string(payload)),
+          "']");
+    });
+  }
+
+  return text;
+}
+
+bool StatusRep::operator==(const StatusRep& other) const {
+  assert(this != &other);
+  if (code_ != other.code_) return false;
+  if (message_ != other.message_) return false;
+  const status_internal::Payloads* this_payloads = payloads_.get();
+  const status_internal::Payloads* other_payloads = other.payloads_.get();
+
+  const status_internal::Payloads no_payloads;
+  const status_internal::Payloads* larger_payloads =
+      this_payloads ? this_payloads : &no_payloads;
+  const status_internal::Payloads* smaller_payloads =
+      other_payloads ? other_payloads : &no_payloads;
+  if (larger_payloads->size() < smaller_payloads->size()) {
+    std::swap(larger_payloads, smaller_payloads);
+  }
+  if ((larger_payloads->size() - smaller_payloads->size()) > 1) return false;
+  // Payloads can be ordered differently, so we can't just compare payload
+  // vectors.
+  for (const auto& payload : *larger_payloads) {
+
+    bool found = false;
+    for (const auto& other_payload : *smaller_payloads) {
+      if (payload.type_url == other_payload.type_url) {
+        if (payload.payload != other_payload.payload) {
+          return false;
+        }
+        found = true;
+        break;
+      }
+    }
+    if (!found) return false;
+  }
+  return true;
+}
+
+StatusRep* StatusRep::CloneAndUnref() const {
+  // Optimization: no need to create a clone if we already have a refcount of 1.
+  if (ref_.load(std::memory_order_acquire) == 1) {
+    // All StatusRep instances are heap allocated and mutable, therefore this
+    // const_cast will never cast away const from a stack instance.
+    //
+    // CloneAndUnref is the only method that doesn't involve an external cast to
+    // get a mutable StatusRep* from the uintptr_t rep stored in Status.
+    return const_cast<StatusRep*>(this);
+  }
+  std::unique_ptr<status_internal::Payloads> payloads;
+  if (payloads_) {
+    payloads = absl::make_unique<status_internal::Payloads>(*payloads_);
+  }
+  auto* new_rep = new StatusRep(code_, message_, std::move(payloads));
+  Unref();
+  return new_rep;
+}
+
+// Convert canonical code to a value known to this binary.
+absl::StatusCode MapToLocalCode(int value) {
+  absl::StatusCode code = static_cast<absl::StatusCode>(value);
+  switch (code) {
+    case absl::StatusCode::kOk:
+    case absl::StatusCode::kCancelled:
+    case absl::StatusCode::kUnknown:
+    case absl::StatusCode::kInvalidArgument:
+    case absl::StatusCode::kDeadlineExceeded:
+    case absl::StatusCode::kNotFound:
+    case absl::StatusCode::kAlreadyExists:
+    case absl::StatusCode::kPermissionDenied:
+    case absl::StatusCode::kResourceExhausted:
+    case absl::StatusCode::kFailedPrecondition:
+    case absl::StatusCode::kAborted:
+    case absl::StatusCode::kOutOfRange:
+    case absl::StatusCode::kUnimplemented:
+    case absl::StatusCode::kInternal:
+    case absl::StatusCode::kUnavailable:
+    case absl::StatusCode::kDataLoss:
+    case absl::StatusCode::kUnauthenticated:
+      return code;
+    default:
+      return absl::StatusCode::kUnknown;
+  }
+}
+
+std::string* MakeCheckFailString(const absl::Status* status,
+                                 const char* prefix) {
+  return new std::string(
+      absl::StrCat(prefix, " (",
+                   status->ToString(StatusToStringMode::kWithEverything), ")"));
+}
+
+}  // namespace status_internal
+
+ABSL_NAMESPACE_END
+}  // namespace absl
diff --git a/absl/status/internal/status_internal.h b/absl/status/internal/status_internal.h
index f22c611d..a445ce37 100644
--- a/absl/status/internal/status_internal.h
+++ b/absl/status/internal/status_internal.h
@@ -14,13 +14,18 @@
 #ifndef ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
 #define ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
 
+#include <atomic>
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <utility>
 
 #include "absl/base/attributes.h"
+#include "absl/base/config.h"
 #include "absl/container/inlined_vector.h"
 #include "absl/strings/cord.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
 
 #ifndef SWIG
 // Disabled for SWIG as it doesn't parse attributes correctly.
@@ -44,6 +49,7 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 
 enum class StatusCode : int;
+enum class StatusToStringMode : int;
 
 namespace status_internal {
 
@@ -56,22 +62,54 @@ struct Payload {
 using Payloads = absl::InlinedVector<Payload, 1>;
 
 // Reference-counted representation of Status data.
-struct StatusRep {
+class StatusRep {
+ public:
   StatusRep(absl::StatusCode code_arg, absl::string_view message_arg,
             std::unique_ptr<status_internal::Payloads> payloads_arg)
-      : ref(int32_t{1}),
-        code(code_arg),
-        message(message_arg),
-        payloads(std::move(payloads_arg)) {}
-
-  std::atomic<int32_t> ref;
-  absl::StatusCode code;
+      : ref_(int32_t{1}),
+        code_(code_arg),
+        message_(message_arg),
+        payloads_(std::move(payloads_arg)) {}
+
+  absl::StatusCode code() const { return code_; }
+  const std::string& message() const { return message_; }
+
+  // Ref and unref are const to allow access through a const pointer, and are
+  // used during copying operations.
+  void Ref() const { ref_.fetch_add(1, std::memory_order_relaxed); }
+  void Unref() const;
+
+  // Payload methods correspond to the same methods in absl::Status.
+  absl::optional<absl::Cord> GetPayload(absl::string_view type_url) const;
+  void SetPayload(absl::string_view type_url, absl::Cord payload);
+  struct EraseResult {
+    bool erased;
+    uintptr_t new_rep;
+  };
+  EraseResult ErasePayload(absl::string_view type_url);
+  void ForEachPayload(
+      absl::FunctionRef<void(absl::string_view, const absl::Cord&)> visitor)
+      const;
+
+  std::string ToString(StatusToStringMode mode) const;
+
+  bool operator==(const StatusRep& other) const;
+  bool operator!=(const StatusRep& other) const { return !(*this == other); }
+
+  // Returns an equivalent heap allocated StatusRep with refcount 1.
+  //
+  // `this` is not safe to be used after calling as it may have been deleted.
+  StatusRep* CloneAndUnref() const;
+
+ private:
+  mutable std::atomic<int32_t> ref_;
+  absl::StatusCode code_;
 
   // As an internal implementation detail, we guarantee that if status.message()
   // is non-empty, then the resulting string_view is null terminated.
   // This is required to implement 'StatusMessageAsCStr(...)'
-  std::string message;
-  std::unique_ptr<status_internal::Payloads> payloads;
+  std::string message_;
+  std::unique_ptr<status_internal::Payloads> payloads_;
 };
 
 absl::StatusCode MapToLocalCode(int value);
diff --git a/absl/status/status.cc b/absl/status/status.cc
index 911f4b28..7eb5d66a 100644
--- a/absl/status/status.cc
+++ b/absl/status/status.cc
@@ -22,7 +22,6 @@
 #include <memory>
 #include <ostream>
 #include <string>
-#include <utility>
 
 #include "absl/base/attributes.h"
 #include "absl/base/config.h"
@@ -31,17 +30,12 @@
 #include "absl/base/macros.h"
 #include "absl/debugging/stacktrace.h"
 #include "absl/debugging/symbolize.h"
-#include "absl/functional/function_ref.h"
-#include "absl/memory/memory.h"
 #include "absl/status/internal/status_internal.h"
-#include "absl/status/status_payload_printer.h"
-#include "absl/strings/escaping.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_format.h"
 #include "absl/strings/str_split.h"
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
-#include "absl/types/span.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
@@ -95,120 +89,6 @@ std::ostream& operator<<(std::ostream& os, StatusCode code) {
   return os << StatusCodeToString(code);
 }
 
-namespace status_internal {
-
-static absl::optional<size_t> FindPayloadIndexByUrl(
-    const Payloads* payloads, absl::string_view type_url) {
-  if (payloads == nullptr) return absl::nullopt;
-
-  for (size_t i = 0; i < payloads->size(); ++i) {
-    if ((*payloads)[i].type_url == type_url) return i;
-  }
-
-  return absl::nullopt;
-}
-
-// Convert canonical code to a value known to this binary.
-absl::StatusCode MapToLocalCode(int value) {
-  absl::StatusCode code = static_cast<absl::StatusCode>(value);
-  switch (code) {
-    case absl::StatusCode::kOk:
-    case absl::StatusCode::kCancelled:
-    case absl::StatusCode::kUnknown:
-    case absl::StatusCode::kInvalidArgument:
-    case absl::StatusCode::kDeadlineExceeded:
-    case absl::StatusCode::kNotFound:
-    case absl::StatusCode::kAlreadyExists:
-    case absl::StatusCode::kPermissionDenied:
-    case absl::StatusCode::kResourceExhausted:
-    case absl::StatusCode::kFailedPrecondition:
-    case absl::StatusCode::kAborted:
-    case absl::StatusCode::kOutOfRange:
-    case absl::StatusCode::kUnimplemented:
-    case absl::StatusCode::kInternal:
-    case absl::StatusCode::kUnavailable:
-    case absl::StatusCode::kDataLoss:
-    case absl::StatusCode::kUnauthenticated:
-      return code;
-    default:
-      return absl::StatusCode::kUnknown;
-  }
-}
-}  // namespace status_internal
-
-absl::optional<absl::Cord> Status::GetPayload(
-    absl::string_view type_url) const {
-  const auto* payloads = GetPayloads();
-  absl::optional<size_t> index =
-      status_internal::FindPayloadIndexByUrl(payloads, type_url);
-  if (index.has_value()) return (*payloads)[index.value()].payload;
-
-  return absl::nullopt;
-}
-
-void Status::SetPayload(absl::string_view type_url, absl::Cord payload) {
-  if (ok()) return;
-
-  PrepareToModify();
-
-  status_internal::StatusRep* rep = RepToPointer(rep_);
-  if (!rep->payloads) {
-    rep->payloads = absl::make_unique<status_internal::Payloads>();
-  }
-
-  absl::optional<size_t> index =
-      status_internal::FindPayloadIndexByUrl(rep->payloads.get(), type_url);
-  if (index.has_value()) {
-    (*rep->payloads)[index.value()].payload = std::move(payload);
-    return;
-  }
-
-  rep->payloads->push_back({std::string(type_url), std::move(payload)});
-}
-
-bool Status::ErasePayload(absl::string_view type_url) {
-  absl::optional<size_t> index =
-      status_internal::FindPayloadIndexByUrl(GetPayloads(), type_url);
-  if (index.has_value()) {
-    PrepareToModify();
-    GetPayloads()->erase(GetPayloads()->begin() + index.value());
-    if (GetPayloads()->empty() && message().empty()) {
-      // Special case: If this can be represented inlined, it MUST be
-      // inlined (EqualsSlow depends on this behavior).
-      StatusCode c = static_cast<StatusCode>(raw_code());
-      Unref(rep_);
-      rep_ = CodeToInlinedRep(c);
-    }
-    return true;
-  }
-
-  return false;
-}
-
-void Status::ForEachPayload(
-    absl::FunctionRef<void(absl::string_view, const absl::Cord&)> visitor)
-    const {
-  if (auto* payloads = GetPayloads()) {
-    bool in_reverse =
-        payloads->size() > 1 && reinterpret_cast<uintptr_t>(payloads) % 13 > 6;
-
-    for (size_t index = 0; index < payloads->size(); ++index) {
-      const auto& elem =
-          (*payloads)[in_reverse ? payloads->size() - 1 - index : index];
-
-#ifdef NDEBUG
-      visitor(elem.type_url, elem.payload);
-#else
-      // In debug mode invalidate the type url to prevent users from relying on
-      // this string lifetime.
-
-      // NOLINTNEXTLINE intentional extra conversion to force temporary.
-      visitor(std::string(elem.type_url), elem.payload);
-#endif  // NDEBUG
-    }
-  }
-}
-
 const std::string* Status::EmptyString() {
   static union EmptyString {
     std::string str;
@@ -226,17 +106,6 @@ const std::string* Status::MovedFromString() {
   return moved_from_string;
 }
 
-void Status::UnrefNonInlined(uintptr_t rep) {
-  status_internal::StatusRep* r = RepToPointer(rep);
-  // Fast path: if ref==1, there is no need for a RefCountDec (since
-  // this is the only reference and therefore no other thread is
-  // allowed to be mucking with r).
-  if (r->ref.load(std::memory_order_acquire) == 1 ||
-      r->ref.fetch_sub(1, std::memory_order_acq_rel) - 1 == 0) {
-    delete r;
-  }
-}
-
 Status::Status(absl::StatusCode code, absl::string_view msg)
     : rep_(CodeToInlinedRep(code)) {
   if (code != absl::StatusCode::kOk && !msg.empty()) {
@@ -244,97 +113,19 @@ Status::Status(absl::StatusCode code, absl::string_view msg)
   }
 }
 
-int Status::raw_code() const {
-  if (IsInlined(rep_)) {
-    return static_cast<int>(InlinedRepToCode(rep_));
-  }
-  status_internal::StatusRep* rep = RepToPointer(rep_);
-  return static_cast<int>(rep->code);
-}
-
-absl::StatusCode Status::code() const {
-  return status_internal::MapToLocalCode(raw_code());
-}
-
-void Status::PrepareToModify() {
-  ABSL_RAW_CHECK(!ok(), "PrepareToModify shouldn't be called on OK status.");
-  if (IsInlined(rep_)) {
-    rep_ = PointerToRep(new status_internal::StatusRep(
-        static_cast<absl::StatusCode>(raw_code()), absl::string_view(),
-        nullptr));
-    return;
-  }
-
-  uintptr_t rep_i = rep_;
-  status_internal::StatusRep* rep = RepToPointer(rep_);
-  if (rep->ref.load(std::memory_order_acquire) != 1) {
-    std::unique_ptr<status_internal::Payloads> payloads;
-    if (rep->payloads) {
-      payloads = absl::make_unique<status_internal::Payloads>(*rep->payloads);
-    }
-    status_internal::StatusRep* const new_rep = new status_internal::StatusRep(
-        rep->code, message(), std::move(payloads));
-    rep_ = PointerToRep(new_rep);
-    UnrefNonInlined(rep_i);
+status_internal::StatusRep* Status::PrepareToModify(uintptr_t rep) {
+  if (IsInlined(rep)) {
+    return new status_internal::StatusRep(InlinedRepToCode(rep),
+                                          absl::string_view(), nullptr);
   }
+  return RepToPointer(rep)->CloneAndUnref();
 }
 
-bool Status::EqualsSlow(const absl::Status& a, const absl::Status& b) {
-  if (IsInlined(a.rep_) != IsInlined(b.rep_)) return false;
-  if (a.message() != b.message()) return false;
-  if (a.raw_code() != b.raw_code()) return false;
-  if (a.GetPayloads() == b.GetPayloads()) return true;
-
-  const status_internal::Payloads no_payloads;
-  const status_internal::Payloads* larger_payloads =
-      a.GetPayloads() ? a.GetPayloads() : &no_payloads;
-  const status_internal::Payloads* smaller_payloads =
-      b.GetPayloads() ? b.GetPayloads() : &no_payloads;
-  if (larger_payloads->size() < smaller_payloads->size()) {
-    std::swap(larger_payloads, smaller_payloads);
-  }
-  if ((larger_payloads->size() - smaller_payloads->size()) > 1) return false;
-  // Payloads can be ordered differently, so we can't just compare payload
-  // vectors.
-  for (const auto& payload : *larger_payloads) {
-
-    bool found = false;
-    for (const auto& other_payload : *smaller_payloads) {
-      if (payload.type_url == other_payload.type_url) {
-        if (payload.payload != other_payload.payload) {
-          return false;
-        }
-        found = true;
-        break;
-      }
-    }
-    if (!found) return false;
+std::string Status::ToStringSlow(uintptr_t rep, StatusToStringMode mode) {
+  if (IsInlined(rep)) {
+    return absl::StrCat(absl::StatusCodeToString(InlinedRepToCode(rep)), ": ");
   }
-  return true;
-}
-
-std::string Status::ToStringSlow(StatusToStringMode mode) const {
-  std::string text;
-  absl::StrAppend(&text, absl::StatusCodeToString(code()), ": ", message());
-
-  const bool with_payload = (mode & StatusToStringMode::kWithPayload) ==
-                            StatusToStringMode::kWithPayload;
-
-  if (with_payload) {
-    status_internal::StatusPayloadPrinter printer =
-        status_internal::GetStatusPayloadPrinter();
-    this->ForEachPayload([&](absl::string_view type_url,
-                             const absl::Cord& payload) {
-      absl::optional<std::string> result;
-      if (printer) result = printer(type_url, payload);
-      absl::StrAppend(
-          &text, " [", type_url, "='",
-          result.has_value() ? *result : absl::CHexEscape(std::string(payload)),
-          "']");
-    });
-  }
-
-  return text;
+  return RepToPointer(rep)->ToString(mode);
 }
 
 std::ostream& operator<<(std::ostream& os, const Status& x) {
@@ -623,17 +414,6 @@ Status ErrnoToStatus(int error_number, absl::string_view message) {
                 MessageForErrnoToStatus(error_number, message));
 }
 
-namespace status_internal {
-
-std::string* MakeCheckFailString(const absl::Status* status,
-                                 const char* prefix) {
-  return new std::string(
-      absl::StrCat(prefix, " (",
-                   status->ToString(StatusToStringMode::kWithEverything), ")"));
-}
-
-}  // namespace status_internal
-
 const char* StatusMessageAsCStr(const Status& status) {
   // As an internal implementation detail, we guarantee that if status.message()
   // is non-empty, then the resulting string_view is null terminated.
diff --git a/absl/status/status.h b/absl/status/status.h
index 2dac2fea..2f03bb64 100644
--- a/absl/status/status.h
+++ b/absl/status/status.h
@@ -59,10 +59,12 @@
 
 #include "absl/base/attributes.h"
 #include "absl/base/config.h"
+#include "absl/base/macros.h"
 #include "absl/base/optimization.h"
 #include "absl/functional/function_ref.h"
 #include "absl/status/internal/status_internal.h"
 #include "absl/strings/cord.h"
+#include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
 
@@ -607,18 +609,15 @@ class Status final {
   // code, and an empty error message.
   explicit Status(absl::StatusCode code);
 
-  static void UnrefNonInlined(uintptr_t rep);
+  // Underlying constructor for status from a rep_.
+  explicit Status(uintptr_t rep) : rep_(rep) {}
+
   static void Ref(uintptr_t rep);
   static void Unref(uintptr_t rep);
 
   // REQUIRES: !ok()
-  // Ensures rep_ is not shared with any other Status.
-  void PrepareToModify();
-
-  const status_internal::Payloads* GetPayloads() const;
-  status_internal::Payloads* GetPayloads();
-
-  static bool EqualsSlow(const absl::Status& a, const absl::Status& b);
+  // Ensures rep is not inlined or shared with any other Status.
+  static status_internal::StatusRep* PrepareToModify(uintptr_t rep);
 
   // MSVC 14.0 limitation requires the const.
   static constexpr const char kMovedFromString[] =
@@ -629,24 +628,24 @@ class Status final {
 
   // Returns whether rep contains an inlined representation.
   // See rep_ for details.
-  static bool IsInlined(uintptr_t rep);
+  static constexpr bool IsInlined(uintptr_t rep);
 
   // Indicates whether this Status was the rhs of a move operation. See rep_
   // for details.
-  static bool IsMovedFrom(uintptr_t rep);
-  static uintptr_t MovedFromRep();
+  static constexpr bool IsMovedFrom(uintptr_t rep);
+  static constexpr uintptr_t MovedFromRep();
 
   // Convert between error::Code and the inlined uintptr_t representation used
   // by rep_. See rep_ for details.
-  static uintptr_t CodeToInlinedRep(absl::StatusCode code);
-  static absl::StatusCode InlinedRepToCode(uintptr_t rep);
+  static constexpr uintptr_t CodeToInlinedRep(absl::StatusCode code);
+  static constexpr absl::StatusCode InlinedRepToCode(uintptr_t rep);
 
   // Converts between StatusRep* and the external uintptr_t representation used
   // by rep_. See rep_ for details.
   static uintptr_t PointerToRep(status_internal::StatusRep* r);
-  static status_internal::StatusRep* RepToPointer(uintptr_t r);
+  static const status_internal::StatusRep* RepToPointer(uintptr_t r);
 
-  std::string ToStringSlow(StatusToStringMode mode) const;
+  static std::string ToStringSlow(uintptr_t rep, StatusToStringMode mode);
 
   // Status supports two different representations.
   //  - When the low bit is set it is an inlined representation.
@@ -657,6 +656,8 @@ class Status final {
   //    In this case all the data comes from a heap allocated Rep object.
   //    rep_ is a status_internal::StatusRep* pointer to that structure.
   uintptr_t rep_;
+
+  friend class status_internal::StatusRep;
 };
 
 // OkStatus()
@@ -760,11 +761,11 @@ Status ErrnoToStatus(int error_number, absl::string_view message);
 // Implementation details follow
 //------------------------------------------------------------------------------
 
-inline Status::Status() : rep_(CodeToInlinedRep(absl::StatusCode::kOk)) {}
+inline Status::Status() : Status(absl::StatusCode::kOk) {}
 
-inline Status::Status(absl::StatusCode code) : rep_(CodeToInlinedRep(code)) {}
+inline Status::Status(absl::StatusCode code) : Status(CodeToInlinedRep(code)) {}
 
-inline Status::Status(const Status& x) : rep_(x.rep_) { Ref(rep_); }
+inline Status::Status(const Status& x) : Status(x.rep_) { Ref(rep_); }
 
 inline Status& Status::operator=(const Status& x) {
   uintptr_t old_rep = rep_;
@@ -776,7 +777,7 @@ inline Status& Status::operator=(const Status& x) {
   return *this;
 }
 
-inline Status::Status(Status&& x) noexcept : rep_(x.rep_) {
+inline Status::Status(Status&& x) noexcept : Status(x.rep_) {
   x.rep_ = MovedFromRep();
 }
 
@@ -808,15 +809,27 @@ inline bool Status::ok() const {
   return rep_ == CodeToInlinedRep(absl::StatusCode::kOk);
 }
 
+inline absl::StatusCode Status::code() const {
+  return status_internal::MapToLocalCode(raw_code());
+}
+
+inline int Status::raw_code() const {
+  if (IsInlined(rep_)) return static_cast<int>(InlinedRepToCode(rep_));
+  return static_cast<int>(RepToPointer(rep_)->code());
+}
+
 inline absl::string_view Status::message() const {
   return !IsInlined(rep_)
-             ? RepToPointer(rep_)->message
+             ? RepToPointer(rep_)->message()
              : (IsMovedFrom(rep_) ? absl::string_view(kMovedFromString)
                                   : absl::string_view());
 }
 
 inline bool operator==(const Status& lhs, const Status& rhs) {
-  return lhs.rep_ == rhs.rep_ || Status::EqualsSlow(lhs, rhs);
+  if (lhs.rep_ == rhs.rep_) return true;
+  if (Status::IsInlined(lhs.rep_)) return false;
+  if (Status::IsInlined(rhs.rep_)) return false;
+  return *Status::RepToPointer(lhs.rep_) == *Status::RepToPointer(rhs.rep_);
 }
 
 inline bool operator!=(const Status& lhs, const Status& rhs) {
@@ -824,7 +837,7 @@ inline bool operator!=(const Status& lhs, const Status& rhs) {
 }
 
 inline std::string Status::ToString(StatusToStringMode mode) const {
-  return ok() ? "OK" : ToStringSlow(mode);
+  return ok() ? "OK" : ToStringSlow(rep_, mode);
 }
 
 inline void Status::IgnoreError() const {
@@ -836,34 +849,54 @@ inline void swap(absl::Status& a, absl::Status& b) {
   swap(a.rep_, b.rep_);
 }
 
-inline const status_internal::Payloads* Status::GetPayloads() const {
-  return IsInlined(rep_) ? nullptr : RepToPointer(rep_)->payloads.get();
+inline absl::optional<absl::Cord> Status::GetPayload(
+    absl::string_view type_url) const {
+  if (IsInlined(rep_)) return absl::nullopt;
+  return RepToPointer(rep_)->GetPayload(type_url);
 }
 
-inline status_internal::Payloads* Status::GetPayloads() {
-  return IsInlined(rep_) ? nullptr : RepToPointer(rep_)->payloads.get();
+inline void Status::SetPayload(absl::string_view type_url, absl::Cord payload) {
+  if (ok()) return;
+  status_internal::StatusRep* rep = PrepareToModify(rep_);
+  rep->SetPayload(type_url, std::move(payload));
+  rep_ = PointerToRep(rep);
 }
 
-inline bool Status::IsInlined(uintptr_t rep) { return (rep & 1) != 0; }
-
-inline bool Status::IsMovedFrom(uintptr_t rep) { return (rep & 2) != 0; }
+inline bool Status::ErasePayload(absl::string_view type_url) {
+  if (IsInlined(rep_)) return false;
+  status_internal::StatusRep* rep = PrepareToModify(rep_);
+  auto res = rep->ErasePayload(type_url);
+  rep_ = res.new_rep;
+  return res.erased;
+}
 
-inline uintptr_t Status::MovedFromRep() {
-  return CodeToInlinedRep(absl::StatusCode::kInternal) | 2;
+inline void Status::ForEachPayload(
+    absl::FunctionRef<void(absl::string_view, const absl::Cord&)> visitor)
+    const {
+  if (IsInlined(rep_)) return;
+  RepToPointer(rep_)->ForEachPayload(visitor);
 }
 
-inline uintptr_t Status::CodeToInlinedRep(absl::StatusCode code) {
+constexpr bool Status::IsInlined(uintptr_t rep) { return (rep & 1) != 0; }
+
+constexpr bool Status::IsMovedFrom(uintptr_t rep) { return (rep & 2) != 0; }
+
+constexpr uintptr_t Status::CodeToInlinedRep(absl::StatusCode code) {
   return (static_cast<uintptr_t>(code) << 2) + 1;
 }
 
-inline absl::StatusCode Status::InlinedRepToCode(uintptr_t rep) {
-  assert(IsInlined(rep));
+constexpr absl::StatusCode Status::InlinedRepToCode(uintptr_t rep) {
+  ABSL_ASSERT(IsInlined(rep));
   return static_cast<absl::StatusCode>(rep >> 2);
 }
 
-inline status_internal::StatusRep* Status::RepToPointer(uintptr_t rep) {
+constexpr uintptr_t Status::MovedFromRep() {
+  return CodeToInlinedRep(absl::StatusCode::kInternal) | 2;
+}
+
+inline const status_internal::StatusRep* Status::RepToPointer(uintptr_t rep) {
   assert(!IsInlined(rep));
-  return reinterpret_cast<status_internal::StatusRep*>(rep);
+  return reinterpret_cast<const status_internal::StatusRep*>(rep);
 }
 
 inline uintptr_t Status::PointerToRep(status_internal::StatusRep* rep) {
@@ -871,15 +904,11 @@ inline uintptr_t Status::PointerToRep(status_internal::StatusRep* rep) {
 }
 
 inline void Status::Ref(uintptr_t rep) {
-  if (!IsInlined(rep)) {
-    RepToPointer(rep)->ref.fetch_add(1, std::memory_order_relaxed);
-  }
+  if (!IsInlined(rep)) RepToPointer(rep)->Ref();
 }
 
 inline void Status::Unref(uintptr_t rep) {
-  if (!IsInlined(rep)) {
-    UnrefNonInlined(rep);
-  }
+  if (!IsInlined(rep)) RepToPointer(rep)->Unref();
 }
 
 inline Status OkStatus() { return Status(); }