1 /*
   2  * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 #ifndef SHARE_VM_LOGGING_LOG_HPP
  25 #define SHARE_VM_LOGGING_LOG_HPP
  26 
  27 #include "logging/logLevel.hpp"
  28 #include "logging/logPrefix.hpp"
  29 #include "logging/logTagSet.hpp"
  30 #include "logging/logTag.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "runtime/os.hpp"
  33 #include "utilities/debug.hpp"
  34 #include "utilities/ostream.hpp"
  35 
  36 //
  37 // Logging macros
  38 //
  39 // Usage:
  40 //   log_<level>(<comma separated log tags>)(<printf-style log arguments>);
  41 // e.g.
  42 //   log_debug(logging)("message %d", i);
  43 //
  44 // Note that these macros will not evaluate the arguments unless the logging is enabled.
  45 //
  46 #define log_error(...)   (!log_is_enabled(Error, __VA_ARGS__))   ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Error>
  47 #define log_warning(...) (!log_is_enabled(Warning, __VA_ARGS__)) ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Warning>
  48 #define log_info(...)    (!log_is_enabled(Info, __VA_ARGS__))    ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Info>
  49 #define log_debug(...)   (!log_is_enabled(Debug, __VA_ARGS__))   ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Debug>
  50 #define log_trace(...)   (!log_is_enabled(Trace, __VA_ARGS__))   ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Trace>
  51 
  52 // Macros for logging that should be excluded in product builds.
  53 // Available for levels Info, Debug and Trace. Includes test macro that
  54 // evaluates to false in product builds.
  55 #ifndef PRODUCT
  56 #define log_develop_info(...)  (!log_is_enabled(Info, __VA_ARGS__))   ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Info>
  57 #define log_develop_debug(...) (!log_is_enabled(Debug, __VA_ARGS__)) ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Debug>
  58 #define log_develop_trace(...) (!log_is_enabled(Trace, __VA_ARGS__))  ? (void)0 : LogImpl<LOG_TAGS(__VA_ARGS__)>::write<LogLevel::Trace>
  59 #define log_develop_is_enabled(level, ...)  log_is_enabled(level, __VA_ARGS__)
  60 #else
  61 #define DUMMY_ARGUMENT_CONSUMER(...)
  62 #define log_develop_info(...)  DUMMY_ARGUMENT_CONSUMER
  63 #define log_develop_debug(...) DUMMY_ARGUMENT_CONSUMER
  64 #define log_develop_trace(...) DUMMY_ARGUMENT_CONSUMER
  65 #define log_develop_is_enabled(...)  false
  66 #endif
  67 
  68 // Convenience macro to test if the logging is enabled on the specified level for given tags.
  69 #define log_is_enabled(level, ...) (LogImpl<LOG_TAGS(__VA_ARGS__)>::is_level(LogLevel::level))
  70 
  71 //
  72 // Log class for more advanced logging scenarios.
  73 // Has printf-style member functions for each log level (trace(), debug(), etc).
  74 //
  75 // Also has outputStream compatible API for the different log-levels.
  76 // The streams are resource allocated when requested and are accessed through
  77 // calls to <level>_stream() functions (trace_stream(), debug_stream(), etc).
  78 //
  79 // Example usage:
  80 //   Log(logging) log;
  81 //   if (log.is_debug()) {
  82 //     ...
  83 //     log.debug("result = %d", result).trace(" tracing info");
  84 //     obj->print_on(log.debug_stream());
  85 //   }
  86 //
  87 #define Log(...)  LogImpl<LOG_TAGS(__VA_ARGS__)>
  88 
  89 template <LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag>
  90 class LogImpl;
  91 
  92 // Non-template helper class for implementing write-slowpath in cpp
  93 class LogWriteHelper : AllStatic {
  94  private:
  95 
  96   template <LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag>
  97   friend class LogImpl;
  98 
  99   ATTRIBUTE_PRINTF(6, 0)
 100   static void write_large(LogTagSet& lts,
 101                           LogLevelType level,
 102                           const char* prefix,
 103                           size_t prefix_len,
 104                           size_t msg_len,
 105                           const char* fmt,
 106                           va_list args);
 107 };
 108 
 109 //
 110 // Log class that embeds both log tags and a log level.
 111 //
 112 // The class provides a way to write the tags and log level once,
 113 // so that redundant specification of tags or levels can be avoided.
 114 //
 115 // Example usage:
 116 //   LogTarget(Debug, gc) out;
 117 //   if (out.is_enabled()) {
 118 //     ...
 119 //     out.print("Worker: %u", i);
 120 //     out.print(" data: %d", x);
 121 //     ...
 122 //     print_stats(out.stream());
 123 //   }
 124 //
 125 #define LogTarget(level, ...) LogTargetImpl<LogLevel::level, LOG_TAGS(__VA_ARGS__)>
 126 
 127 template <LogTagType T0, LogTagType T1 = LogTag::__NO_TAG, LogTagType T2 = LogTag::__NO_TAG, LogTagType T3 = LogTag::__NO_TAG,
 128           LogTagType T4 = LogTag::__NO_TAG, LogTagType GuardTag = LogTag::__NO_TAG>
 129 class LogImpl VALUE_OBJ_CLASS_SPEC {
 130  private:
 131   static const size_t LogBufferSize = 512;
 132  public:
 133   // Make sure no more than the maximum number of tags have been given.
 134   // The GuardTag allows this to be detected if/when it happens. If the GuardTag
 135   // is not __NO_TAG, the number of tags given exceeds the maximum allowed.
 136   STATIC_ASSERT(GuardTag == LogTag::__NO_TAG); // Number of logging tags exceeds maximum supported!
 137 
 138   // Empty constructor to avoid warnings on MSVC about unused variables
 139   // when the log instance is only used for static functions.
 140   LogImpl() {
 141   }
 142 
 143   static bool is_level(LogLevelType level) {
 144     return LogTagSetMapping<T0, T1, T2, T3, T4>::tagset().is_level(level);
 145   }
 146 
 147   ATTRIBUTE_PRINTF(2, 3)
 148   static void write(LogLevelType level, const char* fmt, ...) {
 149     va_list args;
 150     va_start(args, fmt);
 151     vwrite(level, fmt, args);
 152     va_end(args);
 153   };
 154 
 155   template <LogLevelType Level>
 156   ATTRIBUTE_PRINTF(1, 2)
 157   static void write(const char* fmt, ...) {
 158     va_list args;
 159     va_start(args, fmt);
 160     vwrite(Level, fmt, args);
 161     va_end(args);
 162   };
 163 
 164   ATTRIBUTE_PRINTF(2, 0)
 165   static void vwrite(LogLevelType level, const char* fmt, va_list args) {
 166     char buf[LogBufferSize];
 167     va_list saved_args;         // For re-format on buf overflow.
 168     va_copy(saved_args, args);
 169     size_t prefix_len = LogPrefix<T0, T1, T2, T3, T4>::prefix(buf, sizeof(buf));
 170     // Check that string fits in buffer; resize buffer if necessary
 171     int ret = os::log_vsnprintf(buf + prefix_len, sizeof(buf) - prefix_len, fmt, args);
 172     assert(ret >= 0, "Log message buffer issue");
 173     size_t msg_len = ret;
 174     LogTagSet& lts = LogTagSetMapping<T0, T1, T2, T3, T4>::tagset();
 175     if (msg_len >= sizeof(buf)) {
 176       LogWriteHelper::write_large(lts, level, buf, prefix_len, msg_len, fmt, saved_args);
 177     } else {
 178       lts.log(level, buf);
 179     }
 180     va_end(saved_args);
 181   }
 182 
 183 #define LOG_LEVEL(level, name) ATTRIBUTE_PRINTF(2, 0) \
 184   LogImpl& v##name(const char* fmt, va_list args) { \
 185     vwrite(LogLevel::level, fmt, args); \
 186     return *this; \
 187   } \
 188   LogImpl& name(const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3) { \
 189     va_list args; \
 190     va_start(args, fmt); \
 191     vwrite(LogLevel::level, fmt, args); \
 192     va_end(args); \
 193     return *this; \
 194   } \
 195   static bool is_##name() { \
 196     return is_level(LogLevel::level); \
 197   } \
 198   static outputStream* name##_stream() { \
 199     return new logStream(write<LogLevel::level>); \
 200   }
 201   LOG_LEVEL_LIST
 202 #undef LOG_LEVEL
 203 };
 204 
 205 // Combines logging tags and a logging level.
 206 template <LogLevelType level, LogTagType T0, LogTagType T1 = LogTag::__NO_TAG, LogTagType T2 = LogTag::__NO_TAG,
 207           LogTagType T3 = LogTag::__NO_TAG, LogTagType T4 = LogTag::__NO_TAG, LogTagType GuardTag = LogTag::__NO_TAG>
 208 class LogTargetImpl {
 209 public:
 210   // Empty constructor to avoid warnings on MSVC about unused variables
 211   // when the log instance is only used for static functions.
 212   LogTargetImpl() {
 213   }
 214 
 215   static bool is_enabled() {
 216     return LogImpl<T0, T1, T2, T3, T4, GuardTag>::is_level(level);
 217   }
 218 
 219   static void print(const char* fmt, ...) ATTRIBUTE_PRINTF(1, 2) {
 220     va_list args;
 221     va_start(args, fmt);
 222     LogImpl<T0, T1, T2, T3, T4, GuardTag>::vwrite(level, fmt, args);
 223     va_end(args);
 224   }
 225 
 226   static outputStream* stream() {
 227     return new logStream(&LogImpl<T0, T1, T2, T3, T4, GuardTag>::template write<level>);
 228   }
 229 };
 230 
 231 #endif // SHARE_VM_LOGGING_LOG_HPP