Reland: Make DLOG(FATAL) not understood as [[noreturn]]

Having DLOG(FATAL) be [[noreturn]] in debug builds makes dead-code
warnings impossible to satisfy between the release and debug build.

PiperOrigin-RevId: 618257732
Change-Id: Ib1c2cb6a026401fbaa0a6e0770adfc166b964ece

absl/log/absl_log_basic_test.cc

@@ -16,6 +16,7 @@
 #include "absl/log/absl_log.h"
 
 #define ABSL_TEST_LOG ABSL_LOG
+#define ABSL_TEST_DLOG ABSL_DLOG
 
 #include "gtest/gtest.h"
 #include "absl/log/log_basic_test_impl.inc"

absl/log/internal/log_impl.h

@@ -35,11 +35,11 @@
 #ifndef NDEBUG
 #define ABSL_LOG_INTERNAL_DLOG_IMPL(severity)            \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATELESS, true) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 #else
 #define ABSL_LOG_INTERNAL_DLOG_IMPL(severity)             \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATELESS, false) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 #endif
 
 // The `switch` ensures that this expansion is the begnning of a statement (as
@@ -58,7 +58,7 @@
   switch (const int absl_logging_internal_verbose_level = (verbose_level)) \
   case 0:                                                                  \
   default:                                                                 \
-    ABSL_LOG_INTERNAL_LOG_IF_IMPL(                                         \
+    ABSL_LOG_INTERNAL_DLOG_IF_IMPL(                                         \
         _INFO, ABSL_VLOG_IS_ON(absl_logging_internal_verbose_level))       \
         .WithVerbosity(absl_logging_internal_verbose_level)
 #else
@@ -66,7 +66,7 @@
   switch (const int absl_logging_internal_verbose_level = (verbose_level))    \
   case 0:                                                                     \
   default:                                                                    \
-    ABSL_LOG_INTERNAL_LOG_IF_IMPL(                                            \
+    ABSL_LOG_INTERNAL_DLOG_IF_IMPL(                                            \
         _INFO, false && ABSL_VLOG_IS_ON(absl_logging_internal_verbose_level)) \
         .WithVerbosity(absl_logging_internal_verbose_level)
 #endif
@@ -82,11 +82,11 @@
 #ifndef NDEBUG
 #define ABSL_LOG_INTERNAL_DLOG_IF_IMPL(severity, condition)   \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATELESS, condition) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 #else
 #define ABSL_LOG_INTERNAL_DLOG_IF_IMPL(severity, condition)              \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATELESS, false && (condition)) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 #endif
 
 // ABSL_LOG_EVERY_N
@@ -132,36 +132,36 @@
 #ifndef NDEBUG
 #define ABSL_LOG_INTERNAL_DLOG_EVERY_N_IMPL(severity, n) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, true)       \
-  (EveryN, n) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (EveryN, n) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_FIRST_N_IMPL(severity, n) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, true)       \
-  (FirstN, n) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (FirstN, n) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_EVERY_POW_2_IMPL(severity) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, true)        \
-  (EveryPow2) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (EveryPow2) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_EVERY_N_SEC_IMPL(severity, n_seconds) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, true)                   \
-  (EveryNSec, n_seconds) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (EveryNSec, n_seconds) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #else  // def NDEBUG
 #define ABSL_LOG_INTERNAL_DLOG_EVERY_N_IMPL(severity, n) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, false)      \
-  (EveryN, n) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (EveryN, n) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_FIRST_N_IMPL(severity, n) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, false)      \
-  (FirstN, n) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (FirstN, n) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_EVERY_POW_2_IMPL(severity) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, false)       \
-  (EveryPow2) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (EveryPow2) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_EVERY_N_SEC_IMPL(severity, n_seconds) \
   ABSL_LOG_INTERNAL_CONDITION_INFO(STATEFUL, false)                  \
-  (EveryNSec, n_seconds) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+  (EveryNSec, n_seconds) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 #endif  // def NDEBUG
 
 #define ABSL_LOG_INTERNAL_VLOG_EVERY_N_IMPL(verbose_level, n)                \
@@ -243,40 +243,40 @@
 #ifndef NDEBUG
 #define ABSL_LOG_INTERNAL_DLOG_IF_EVERY_N_IMPL(severity, condition, n)  \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, condition)(EveryN, n) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_IF_FIRST_N_IMPL(severity, condition, n)  \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, condition)(FirstN, n) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_IF_EVERY_POW_2_IMPL(severity, condition) \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, condition)(EveryPow2) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_IF_EVERY_N_SEC_IMPL(severity, condition, \
                                                    n_seconds)           \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, condition)(EveryNSec, \
                                                              n_seconds) \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #else  // def NDEBUG
 #define ABSL_LOG_INTERNAL_DLOG_IF_EVERY_N_IMPL(severity, condition, n)   \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, false && (condition))( \
-      EveryN, n) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      EveryN, n) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_IF_FIRST_N_IMPL(severity, condition, n)   \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, false && (condition))( \
-      FirstN, n) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      FirstN, n) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_IF_EVERY_POW_2_IMPL(severity, condition)  \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, false && (condition))( \
-      EveryPow2) ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      EveryPow2) ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 
 #define ABSL_LOG_INTERNAL_DLOG_IF_EVERY_N_SEC_IMPL(severity, condition,  \
                                                    n_seconds)            \
   ABSL_LOG_INTERNAL_CONDITION##severity(STATEFUL, false && (condition))( \
       EveryNSec, n_seconds)                                              \
-      ABSL_LOGGING_INTERNAL_LOG##severity.InternalStream()
+      ABSL_LOGGING_INTERNAL_DLOG##severity.InternalStream()
 #endif  // def NDEBUG
 
 #endif  // ABSL_LOG_INTERNAL_LOG_IMPL_H_

absl/log/internal/log_message.cc

@@ -578,6 +578,13 @@ template void LogMessage::CopyToEncodedBuffer<LogMessage::StringType::kLiteral>(
 template void LogMessage::CopyToEncodedBuffer<
     LogMessage::StringType::kNotLiteral>(char ch, size_t num);
 
+// We intentionally don't return from these destructors. Disable MSVC's warning
+// about the destructor never returning as we do so intentionally here.
+#if defined(_MSC_VER) && !defined(__clang__)
+#pragma warning(push)
+#pragma warning(disable : 4722)
+#endif
+
 LogMessageFatal::LogMessageFatal(const char* file, int line)
     : LogMessage(file, line, absl::LogSeverity::kFatal) {}
 
@@ -587,19 +594,29 @@ LogMessageFatal::LogMessageFatal(const char* file, int line,
   *this << "Check failed: " << failure_msg << " ";
 }
 
-// ABSL_ATTRIBUTE_NORETURN doesn't seem to work on destructors with msvc, so
-// disable msvc's warning about the d'tor never returning.
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(push)
-#pragma warning(disable : 4722)
-#endif
 LogMessageFatal::~LogMessageFatal() {
   Flush();
   FailWithoutStackTrace();
 }
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(pop)
-#endif
+
+LogMessageDebugFatal::LogMessageDebugFatal(const char* file, int line)
+    : LogMessage(file, line, absl::LogSeverity::kFatal) {}
+
+LogMessageDebugFatal::~LogMessageDebugFatal() {
+  Flush();
+  FailWithoutStackTrace();
+}
+
+LogMessageQuietlyDebugFatal::LogMessageQuietlyDebugFatal(const char* file,
+                                                         int line)
+    : LogMessage(file, line, absl::LogSeverity::kFatal) {
+  SetFailQuietly();
+}
+
+LogMessageQuietlyDebugFatal::~LogMessageQuietlyDebugFatal() {
+  Flush();
+  FailQuietly();
+}
 
 LogMessageQuietlyFatal::LogMessageQuietlyFatal(const char* file, int line)
     : LogMessage(file, line, absl::LogSeverity::kFatal) {
@@ -608,17 +625,10 @@ LogMessageQuietlyFatal::LogMessageQuietlyFatal(const char* file, int line)
 
 LogMessageQuietlyFatal::LogMessageQuietlyFatal(const char* file, int line,
                                                absl::string_view failure_msg)
-    : LogMessage(file, line, absl::LogSeverity::kFatal) {
-  SetFailQuietly();
-  *this << "Check failed: " << failure_msg << " ";
+    : LogMessageQuietlyFatal(file, line) {
+    *this << "Check failed: " << failure_msg << " ";
 }
 
-// ABSL_ATTRIBUTE_NORETURN doesn't seem to work on destructors with msvc, so
-// disable msvc's warning about the d'tor never returning.
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(push)
-#pragma warning(disable : 4722)
-#endif
 LogMessageQuietlyFatal::~LogMessageQuietlyFatal() {
   Flush();
   FailQuietly();

absl/log/internal/log_message.h

@@ -357,6 +357,25 @@ class LogMessageFatal final : public LogMessage {
   ABSL_ATTRIBUTE_NORETURN ~LogMessageFatal();
 };
 
+// `LogMessageDebugFatal` ensures the process will exit in failure after logging
+// this message. It matches LogMessageFatal but is not [[noreturn]] as it's used
+// for DLOG(FATAL) variants.
+class LogMessageDebugFatal final : public LogMessage {
+ public:
+  LogMessageDebugFatal(const char* file, int line) ABSL_ATTRIBUTE_COLD;
+  ~LogMessageDebugFatal();
+};
+
+class LogMessageQuietlyDebugFatal final : public LogMessage {
+ public:
+  // DLOG(QFATAL) calls this instead of LogMessageQuietlyFatal to make sure the
+  // destructor is not [[noreturn]] even if this is always FATAL as this is only
+  // invoked when DLOG() is enabled.
+  LogMessageQuietlyDebugFatal(const char* file, int line) ABSL_ATTRIBUTE_COLD;
+  ~LogMessageQuietlyDebugFatal();
+};
+
+// Used for LOG(QFATAL) to make sure it's properly understood as [[noreturn]].
 class LogMessageQuietlyFatal final : public LogMessage {
  public:
   LogMessageQuietlyFatal(const char* file, int line) ABSL_ATTRIBUTE_COLD;

absl/log/internal/strip.h

@@ -38,6 +38,13 @@
   ::absl::log_internal::NullStreamMaybeFatal(::absl::kLogDebugFatal)
 #define ABSL_LOGGING_INTERNAL_LOG_LEVEL(severity) \
   ::absl::log_internal::NullStreamMaybeFatal(absl_log_internal_severity)
+
+// Fatal `DLOG`s expand a little differently to avoid being `[[noreturn]]`.
+#define ABSL_LOGGING_INTERNAL_DLOG_FATAL \
+  ::absl::log_internal::NullStreamMaybeFatal(::absl::LogSeverity::kFatal)
+#define ABSL_LOGGING_INTERNAL_DLOG_QFATAL \
+  ::absl::log_internal::NullStreamMaybeFatal(::absl::LogSeverity::kFatal)
+
 #define ABSL_LOG_INTERNAL_CHECK(failure_message) ABSL_LOGGING_INTERNAL_LOG_FATAL
 #define ABSL_LOG_INTERNAL_QCHECK(failure_message) \
   ABSL_LOGGING_INTERNAL_LOG_QFATAL
@@ -60,6 +67,13 @@
 #define ABSL_LOGGING_INTERNAL_LOG_LEVEL(severity)      \
   ::absl::log_internal::LogMessage(__FILE__, __LINE__, \
                                    absl_log_internal_severity)
+
+// Fatal `DLOG`s expand a little differently to avoid being `[[noreturn]]`.
+#define ABSL_LOGGING_INTERNAL_DLOG_FATAL \
+  ::absl::log_internal::LogMessageDebugFatal(__FILE__, __LINE__)
+#define ABSL_LOGGING_INTERNAL_DLOG_QFATAL \
+  ::absl::log_internal::LogMessageQuietlyDebugFatal(__FILE__, __LINE__)
+
 // These special cases dispatch to special-case constructors that allow us to
 // avoid an extra function call and shrink non-LTO binaries by a percent or so.
 #define ABSL_LOG_INTERNAL_CHECK(failure_message) \
@@ -69,4 +83,11 @@
                                                failure_message)
 #endif  // !defined(STRIP_LOG) || !STRIP_LOG
 
+// This part of a non-fatal `DLOG`s expands the same as `LOG`.
+#define ABSL_LOGGING_INTERNAL_DLOG_INFO ABSL_LOGGING_INTERNAL_LOG_INFO
+#define ABSL_LOGGING_INTERNAL_DLOG_WARNING ABSL_LOGGING_INTERNAL_LOG_WARNING
+#define ABSL_LOGGING_INTERNAL_DLOG_ERROR ABSL_LOGGING_INTERNAL_LOG_ERROR
+#define ABSL_LOGGING_INTERNAL_DLOG_DFATAL ABSL_LOGGING_INTERNAL_LOG_DFATAL
+#define ABSL_LOGGING_INTERNAL_DLOG_LEVEL ABSL_LOGGING_INTERNAL_LOG_LEVEL
+
 #endif  // ABSL_LOG_INTERNAL_STRIP_H_

absl/log/log_basic_test.cc

@@ -16,6 +16,7 @@
 #include "absl/log/log.h"
 
 #define ABSL_TEST_LOG LOG
+#define ABSL_TEST_DLOG DLOG
 
 #include "gtest/gtest.h"
 #include "absl/log/log_basic_test_impl.inc"

absl/log/log_basic_test_impl.inc

@@ -25,6 +25,10 @@
 #error ABSL_TEST_LOG must be defined for these tests to work.
 #endif
 
+#ifndef ABSL_TEST_DLOG
+#error ABSL_TEST_DLOG must be defined for these tests to work.
+#endif
+
 #include <cerrno>
 #include <sstream>
 #include <string>
@@ -34,6 +38,7 @@
 #include "absl/base/internal/sysinfo.h"
 #include "absl/base/log_severity.h"
 #include "absl/log/globals.h"
+#include "absl/log/internal/globals.h"
 #include "absl/log/internal/test_actions.h"
 #include "absl/log/internal/test_helpers.h"
 #include "absl/log/internal/test_matchers.h"
@@ -367,6 +372,27 @@ TEST_P(BasicLogDeathTest, DFatal) {
 }
 #endif
 
+#ifndef NDEBUG
+TEST_P(BasicLogTest, DFatalIsCancellable) {
+  // LOG(DFATAL) does not die when DFATAL death is disabled.
+  absl::log_internal::SetExitOnDFatal(false);
+  ABSL_TEST_LOG(DFATAL) << "hello world";
+  absl::log_internal::SetExitOnDFatal(true);
+}
+
+#if GTEST_HAS_DEATH_TEST
+TEST_P(BasicLogDeathTest, DLogFatalIsNotCancellable) {
+  EXPECT_EXIT(
+      {
+        absl::log_internal::SetExitOnDFatal(false);
+        ABSL_TEST_DLOG(FATAL) << "hello world";
+        absl::log_internal::SetExitOnDFatal(true);
+      },
+      DiedOfFatal, "");
+}
+#endif
+#endif
+
 TEST_P(BasicLogTest, Level) {
   absl::log_internal::ScopedMinLogLevel scoped_min_log_level(GetParam());