Implement Dump-on-DCHECK (via a new LogSeverity).

third_party/WebKit/Source/wtf/Assertions.h

 /*
  * Copyright (C) 2003, 2006, 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 31 matching lines @@
 #include "wtf/build_config.h"
 #include <stdarg.h>
 
 #if OS(WIN)
 #include <windows.h>
 #endif
 
 // Users must test "#if ENABLE(ASSERT)", which helps ensure that code
 // testing this macro has included this header.
 #ifndef ENABLE_ASSERT
-#if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
-/* Disable ASSERT* macros in release mode by default. */
-#define ENABLE_ASSERT 0
-#else
-#define ENABLE_ASSERT 1
-#endif /* defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON) */
+#define ENABLE_ASSERT DCHECK_IS_ON()
 #endif
 
 #ifndef LOG_DISABLED
 #define LOG_DISABLED !ENABLE(ASSERT)
 #endif
 
 // These helper functions are always declared, but not necessarily always
 // defined if the corresponding function is disabled.
 
 WTF_EXPORT void WTFReportAssertionFailure(const char* file,
@@ skipping 82 matching lines @@
 //  Expressions inside them are evaluated in debug builds only.
 //  They are deprecated. We should use:
 //    - DCHECK() for ASSERT()
 //    - NOTREACHED() for ASSERT_NOT_REACHED()
 #if OS(WIN)
 // FIXME: Change to use something other than ASSERT to avoid this conflict with
 // the underlying platform.
 #undef ASSERT
 #endif
 
+// If DCHECK is configured to dump-without-crashing then enable assertions,
+// but also configure them to dump-without-crashing.
+#if defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
+
+#define ASSERT(assertion) DCHECK(assertion)
+#define ASSERT_NOT_REACHED() NOTREACHED()

[Wez, 2016/12/19 23:57:46]

Note that this has significant performance implications. Yay.

[esprehn, 2016/12/20 03:16:29]

What was the perf change? Not sure I understand how switching ASSERT_NOT_REACHED
changed the perf? Note that blink will probably switch all of these to
NOTREACHED() someday so it'd be good to understand what changed?

[Wez, 2017/01/07 00:18:47]

Earlier versions of the patch left Blink assertions disabled, to avoid the
related book-keeping overhead.

+
+// |file| and |line| won't actually be logged, but must be referenced.
+#define DCHECK_AT(assertion, file, line) DCHECK(assertion) << file << line
+
+#else  // defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
+
 #define DCHECK_AT(assertion, file, line)                            \
   LAZY_STREAM(logging::LogMessage(file, line, #assertion).stream(), \
               DCHECK_IS_ON() ? !(assertion) : false)
 
 #if ENABLE(ASSERT)
 
 #define ASSERT(assertion)                                                      \
   (!(assertion) ? (WTFReportAssertionFailure(__FILE__, __LINE__,               \
                                              WTF_PRETTY_FUNCTION, #assertion), \
                    CRASH())                                                    \
                 : (void)0)
 
 #define ASSERT_NOT_REACHED()                                               \
   do {                                                                     \
     WTFReportAssertionFailure(__FILE__, __LINE__, WTF_PRETTY_FUNCTION, 0); \
     CRASH();                                                               \
   } while (0)
 
 #else
 
 #define ASSERT(assertion) ((void)0)
 #define ASSERT_NOT_REACHED() ((void)0)
 
 #endif
 
+#endif  // defined(DCHECK_ALWAYS_ON)
+
 // Users must test "#if ENABLE(SECURITY_ASSERT)", which helps ensure
 // that code testing this macro has included this header.
 #if defined(ADDRESS_SANITIZER) || ENABLE(ASSERT)
 #define ENABLE_SECURITY_ASSERT 1
 #else
 #define ENABLE_SECURITY_ASSERT 0
 #endif
 
 // SECURITY_DCHECK and SECURITY_CHECK
 // Use in places where failure of the assertion indicates a possible security
@@ skipping 97 matching lines @@
     return static_cast<thisType&>(argument);                                  \
   }                                                                           \
   inline const thisType& to##thisType##OrDie(const argumentType& argument) {  \
     CHECK(referencePredicate);                                                \
     return static_cast<const thisType&>(argument);                            \
   }                                                                           \
   void to##thisType##OrDie(const thisType*);                                  \
   void to##thisType##OrDie(const thisType&)
 
 #endif  // WTF_Assertions_h