Add Clang static analysis control to all assert functions in logging.h

base/logging.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_LOGGING_H_
 #define BASE_LOGGING_H_
 
 #include <stddef.h>
 
 #include <cassert>
@@ skipping 271 matching lines @@
 
 // Sets the Log Message Handler that gets passed every log message before
 // it's sent to other log destinations (if any).
 // Returns true to signal that it handled the message and the message
 // should not be sent to other log destinations.
 typedef bool (*LogMessageHandlerFunction)(int severity,
     const char* file, int line, size_t message_start, const std::string& str);
 BASE_EXPORT void SetLogMessageHandler(LogMessageHandlerFunction handler);
 BASE_EXPORT LogMessageHandlerFunction GetLogMessageHandler();
 
+// The ANALYZER_ASSUME_TRUE(bool arg) macro adds compiler-specific hints
+// to Clang which control what code paths are statically analyzed,
+// and is meant to be used in conjunction with assert & assert-like functions.
+// The expression is passed straight through if analysis isn't enabled.
+#if defined(__clang_analyzer__)
+
+inline constexpr bool AnalyzerNoReturn() __attribute__((analyzer_noreturn)) {
+  return false;
+}
+
+inline constexpr bool AnalyzerAssumeTrue(bool arg) {
+  // AnalyzerNoReturn() is invoked and analysis is terminated if |arg| is
+  // false.
+  return arg || AnalyzerNoReturn();
+}
+
+#define ANALYZER_ASSUME_TRUE(arg) ::logging::AnalyzerAssumeTrue(!!(arg))
+
+#else  // !defined(__clang_analyzer__)
+
+#define ANALYZER_ASSUME_TRUE(arg) (arg)
+
+#endif  // defined(__clang_analyzer__)
+
 typedef int LogSeverity;
 const LogSeverity LOG_VERBOSE = -1;  // This is level 1 verbosity
 // Note: the log severities are used to index into the array of names,
 // see log_severity_names.
 const LogSeverity LOG_INFO = 0;
 const LogSeverity LOG_WARNING = 1;
 const LogSeverity LOG_ERROR = 2;
 const LogSeverity LOG_FATAL = 3;
 const LogSeverity LOG_NUM_SEVERITIES = 4;
 
@@ skipping 99 matching lines @@
 
 #define VPLOG(verbose_level) \
   LAZY_STREAM(VPLOG_STREAM(verbose_level), VLOG_IS_ON(verbose_level))
 
 #define VPLOG_IF(verbose_level, condition) \
   LAZY_STREAM(VPLOG_STREAM(verbose_level), \
     VLOG_IS_ON(verbose_level) && (condition))
 
 // TODO(akalin): Add more VLOG variants, e.g. VPLOG.
 
-#define LOG_ASSERT(condition) \
-  LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition ". "
+#define LOG_ASSERT(condition)                       \
+  LOG_IF(FATAL, !(ANALYZER_ASSUME_TRUE(condition))) \
+      << "Assert failed: " #condition ". "
 
 #if defined(OS_WIN)
 #define PLOG_STREAM(severity) \
   COMPACT_GOOGLE_LOG_EX_ ## severity(Win32ErrorLogMessage, \
       ::logging::GetLastSystemErrorCode()).stream()
 #elif defined(OS_POSIX)
 #define PLOG_STREAM(severity) \
   COMPACT_GOOGLE_LOG_EX_ ## severity(ErrnoLogMessage, \
       ::logging::GetLastSystemErrorCode()).stream()
 #endif
@@ skipping 155 matching lines @@
 #define PCHECK(condition)                    \
   __analysis_assume(!!(condition)),          \
       LAZY_STREAM(PLOG_STREAM(FATAL), false) \
           << "Check failed: " #condition ". "
 
 #else  // _PREFAST_
 
 // Do as much work as possible out of line to reduce inline code size.
 #define CHECK(condition)                                                      \
   LAZY_STREAM(::logging::LogMessage(__FILE__, __LINE__, #condition).stream(), \
-              !(condition))
+              !ANALYZER_ASSUME_TRUE(condition))
 
-#define PCHECK(condition)                       \
-  LAZY_STREAM(PLOG_STREAM(FATAL), !(condition)) \
+#define PCHECK(condition)                                           \
+  LAZY_STREAM(PLOG_STREAM(FATAL), !ANALYZER_ASSUME_TRUE(condition)) \
       << "Check failed: " #condition ". "
 
 #endif  // _PREFAST_
 
 // Helper macro for binary operators.
 // Don't use this macro directly in your code, use CHECK_EQ et al below.
 // The 'switch' is used to prevent the 'else' from being ambiguous when the
 // macro is used in an 'if' clause such as:
 // if (a == 1)
 //   CHECK_EQ(2, a);
@@ skipping 76 matching lines @@
 std::string* MakeCheckOpString<unsigned int, unsigned long>(
     const unsigned int&, const unsigned long&, const char* names);
 extern template BASE_EXPORT
 std::string* MakeCheckOpString<std::string, std::string>(
     const std::string&, const std::string&, const char* name);
 
 // Helper functions for CHECK_OP macro.
 // The (int, int) specialization works around the issue that the compiler
 // will not instantiate the template version of the function on values of
 // unnamed enum type - see comment below.
+//
+// The checked condition is wrapped with ANALYZER_ASSUME_TRUE, which under
+// static analysis builds, blocks analysis of the current path if the
+// condition is false.
 #define DEFINE_CHECK_OP_IMPL(name, op)                                       \
   template <class t1, class t2>                                              \
   inline std::string* Check##name##Impl(const t1& v1, const t2& v2,          \
                                         const char* names) {                 \
-    if (v1 op v2)                                                            \
+    if (ANALYZER_ASSUME_TRUE(v1 op v2))                                      \
       return NULL;                                                           \
     else                                                                     \
       return ::logging::MakeCheckOpString(v1, v2, names);                    \
   }                                                                          \
   inline std::string* Check##name##Impl(int v1, int v2, const char* names) { \
-    if (v1 op v2)                                                            \
+    if (ANALYZER_ASSUME_TRUE(v1 op v2))                                      \
       return NULL;                                                           \
     else                                                                     \
       return ::logging::MakeCheckOpString(v1, v2, names);                    \
   }
 DEFINE_CHECK_OP_IMPL(EQ, ==)
 DEFINE_CHECK_OP_IMPL(NE, !=)
 DEFINE_CHECK_OP_IMPL(LE, <=)
 DEFINE_CHECK_OP_IMPL(LT, < )
 DEFINE_CHECK_OP_IMPL(GE, >=)
 DEFINE_CHECK_OP_IMPL(GT, > )
@@ skipping 82 matching lines @@
 #define DCHECK(condition)                    \
   __analysis_assume(!!(condition)),          \
       LAZY_STREAM(LOG_STREAM(DCHECK), false) \
           << "Check failed: " #condition ". "
 
 #define DPCHECK(condition)                    \
   __analysis_assume(!!(condition)),           \
       LAZY_STREAM(PLOG_STREAM(DCHECK), false) \
           << "Check failed: " #condition ". "
 
-#elif defined(__clang_analyzer__)
-
-// Keeps the static analyzer from proceeding along the current codepath,
-// otherwise false positive errors may be generated  by null pointer checks.
-inline constexpr bool AnalyzerNoReturn() __attribute__((analyzer_noreturn)) {
-  return false;
-}
-
-#define DCHECK(condition)                                                     \
-  LAZY_STREAM(                                                                \
-      LOG_STREAM(DCHECK),                                                     \
-      DCHECK_IS_ON() ? (logging::AnalyzerNoReturn() || !(condition)) : false) \
-      << "Check failed: " #condition ". "
-
-#define DPCHECK(condition)                                                    \
-  LAZY_STREAM(                                                                \
-      PLOG_STREAM(DCHECK),                                                    \
-      DCHECK_IS_ON() ? (logging::AnalyzerNoReturn() || !(condition)) : false) \
-      << "Check failed: " #condition ". "
-
-#else
+#else  // !(defined(_PREFAST_) && defined(OS_WIN))
 
 #if DCHECK_IS_ON()
 
-#define DCHECK(condition)                       \
-  LAZY_STREAM(LOG_STREAM(DCHECK), !(condition)) \
+#define DCHECK(condition)                                           \
+  LAZY_STREAM(LOG_STREAM(DCHECK), !ANALYZER_ASSUME_TRUE(condition)) \
       << "Check failed: " #condition ". "
-#define DPCHECK(condition)                       \
-  LAZY_STREAM(PLOG_STREAM(DCHECK), !(condition)) \
+#define DPCHECK(condition)                                           \
+  LAZY_STREAM(PLOG_STREAM(DCHECK), !ANALYZER_ASSUME_TRUE(condition)) \
       << "Check failed: " #condition ". "
 
 #else  // DCHECK_IS_ON()
 
 #define DCHECK(condition) EAT_STREAM_PARAMETERS << !(condition)
 #define DPCHECK(condition) EAT_STREAM_PARAMETERS << !(condition)
 
 #endif  // DCHECK_IS_ON()
 
-#endif
+#endif  // defined(_PREFAST_) && defined(OS_WIN)
 
 // Helper macro for binary operators.
 // Don't use this macro directly in your code, use DCHECK_EQ et al below.
 // The 'switch' is used to prevent the 'else' from being ambiguous when the
 // macro is used in an 'if' clause such as:
 // if (a == 1)
 //   DCHECK_EQ(2, a);
 #if DCHECK_IS_ON()
 
 #define DCHECK_OP(name, op, val1, val2)                                \
@@ skipping 289 matching lines @@
 #elif NOTIMPLEMENTED_POLICY == 5
 #define NOTIMPLEMENTED() do {\
   static bool logged_once = false;\
   LOG_IF(ERROR, !logged_once) << NOTIMPLEMENTED_MSG;\
   logged_once = true;\
 } while(0);\
 EAT_STREAM_PARAMETERS
 #endif
 
 #endif  // BASE_LOGGING_H_