misc: Add panic_if / fatal_if / chatty_assert

This snippet can be used to replace if + {panics, fatals, asserts} constructs.
The idea is to have both the condition checking and a verbose printout in a single statement.  The interface is as follows:

panic_if(foo != bar, "These should be equal: foo %i bar %i", foo, bar);
fatal_if(foo != bar, "These should be equal: foo %i bar %i", foo, bar);
chatty_assert(foo == bar, "These should be equal: foo %i bar %i", foo, bar);

src/base/misc.hh

@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2014 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -82,6 +94,37 @@ M5_PRAGMA_NORETURN(__exit_message)
 //
 #define fatal(...) exit_message("fatal", -1, __VA_ARGS__)
 
+/**
+ * Conditional panic macro that checks the supplied condition and only panics
+ * if the condition is true and allows the programmer to specify diagnostic
+ * printout.  Useful to replace if + panic, or if + print + assert, etc.
+ *
+ * @param cond Condition that is checked; if true -> panic
+ * @param ...  Printf-based format string with arguments, extends printout.
+ */
+#define panic_if(cond, ...) \
+    do { \
+        if ((cond)) \
+            exit_message("panic condition "#cond" occurred", -1, __VA_ARGS__); \
+    } while (0)
+
+
+/**
+ * Conditional fatal macro that checks the supplied condition and only causes a
+ * fatal error if the condition is true and allows the programmer to specify
+ * diagnostic printout.  Useful to replace if + fatal, or if + print + assert,
+ * etc.
+ *
+ * @param cond Condition that is checked; if true -> fatal
+ * @param ...  Printf-based format string with arguments, extends printout.
+ */
+#define fatal_if(cond, ...) \
+    do { \
+        if ((cond)) \
+            exit_message("fatal condition "#cond" occurred", 1, __VA_ARGS__); \
+    } while (0)
+
+
 void
 __base_message(std::ostream &stream, const char *prefix, bool verbose,
           const char *func, const char *file, int line,
@@ -146,4 +189,24 @@ extern bool want_hack, hack_verbose;
 #define hack_once(...) \
     cond_message_once(want_hack, std::cerr, "hack", hack_verbose, __VA_ARGS__)
 
+/**
+ * The chatty assert macro will function like a normal assert, but will allow the
+ * specification of additional, helpful material to aid debugging why the
+ * assertion actually failed.  Like the normal assertion, the chatty_assert
+ * will not be active in fast builds.
+ *
+ * @param cond Condition that is checked; if false -> assert
+ * @param ...  Printf-based format string with arguments, extends printout.
+ */
+#ifdef NDEBUG
+#define chatty_assert(cond, ...)
+#else //!NDEBUG
+#define chatty_assert(cond, ...)                                                \
+    do {                                                                        \
+        if (!(cond)) {                                                          \
+            base_message(std::cerr, "assert("#cond") failing", 1, __VA_ARGS__); \
+            assert(cond);                                                       \
+        }                                                                       \
+    } while (0)
+#endif // NDEBUG
 #endif // __BASE_MISC_HH__