base: Define the gem5_assert macro

gem5_assert is a drop-in replacement for regular assert, except that
the condition must always be valid, compilable code. It allows to
perform clean-up before exiting using the exit method of ExitLogger.

The need for clean-up is detailed in the following issue:
https://gem5.atlassian.net/browse/GEM5-968

Change-Id: Icad1719c0e6fbb066471d1fecfb12eedd65aa690
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45027
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/logging.hh

@@ -309,6 +309,24 @@ class Logger
     } while (0)
 /** @} */ // end of api_logger
 
-} // namespace gem5
+/**
+ * The assert macro will function like a normal assert, but will use panic
+ * instead of straight abort(). This allows to perform some cleaning up in
+ * ExitLogger::exit() before calling abort(). This macro will not check its
+ * condition in fast builds, but it must still be valid code.
+ *
+ * @param cond Condition that is checked; if false -> panic
+ *
+ * \def gem5_assert(cond)
+ *
+ * @ingroup api_logger
+ */
+#define gem5_assert(cond) \
+    do { \
+        if (GEM5_UNLIKELY(!NDEBUG_DEFINED && !static_cast<bool>(cond))) \
+            panic("assert(" # cond ") failed"); \
+    } while (0)
+/** @} */ // end of api_logger
 
+} // namespace gem5
 #endif // __BASE_LOGGING_HH__

src/base/logging.test.cc

@@ -554,3 +554,15 @@ TEST(LoggingDeathTest, ChattyAssert)
     ASSERT_DEATH(chatty_assert(false, "message\n"), ::testing::HasSubstr(
         "panic: assert(false) failed: message\nMemory Usage:"));
 }
+
+/** Test macro gem5_assert. */
+TEST(LoggingDeathTest, gem5Assert)
+{
+#ifdef NDEBUG
+    GTEST_SKIP() << "Skipping as assertions are "
+        "stripped out of fast builds";
+#endif
+    gem5_assert(true);
+    ASSERT_DEATH(gem5_assert(false), ::testing::HasSubstr(
+        "panic: assert(false) failed\nMemory Usage:"));
+}