debug.h

  1/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
  2/* ******************************************************************
  3 * debug
  4 * Part of FSE library
  5 * Copyright (c) Meta Platforms, Inc. and affiliates.
  6 *
  7 * You can contact the author at :
  8 * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
  9 *
 10 * This source code is licensed under both the BSD-style license (found in the
 11 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 12 * in the COPYING file in the root directory of this source tree).
 13 * You may select, at your option, one of the above-listed licenses.
 14****************************************************************** */
 15
 16
 17/*
 18 * The purpose of this header is to enable debug functions.
 19 * They regroup assert(), DEBUGLOG() and RAWLOG() for run-time,
 20 * and DEBUG_STATIC_ASSERT() for compile-time.
 21 *
 22 * By default, DEBUGLEVEL==0, which means run-time debug is disabled.
 23 *
 24 * Level 1 enables assert() only.
 25 * Starting level 2, traces can be generated and pushed to stderr.
 26 * The higher the level, the more verbose the traces.
 27 *
 28 * It's possible to dynamically adjust level using variable g_debug_level,
 29 * which is only declared if DEBUGLEVEL>=2,
 30 * and is a global variable, not multi-thread protected (use with care)
 31 */
 32
 33#ifndef DEBUG_H_12987983217
 34#define DEBUG_H_12987983217
 35
 36
 37/* static assert is triggered at compile time, leaving no runtime artefact.
 38 * static assert only works with compile-time constants.
 39 * Also, this variant can only be used inside a function. */
 40#define DEBUG_STATIC_ASSERT(c) (void)sizeof(char[(c) ? 1 : -1])
 41
 42
 43/* DEBUGLEVEL is expected to be defined externally,
 44 * typically through compiler command line.
 45 * Value must be a number. */
 46#ifndef DEBUGLEVEL
 47#  define DEBUGLEVEL 0
 48#endif
 49
 50
 51/* recommended values for DEBUGLEVEL :
 52 * 0 : release mode, no debug, all run-time checks disabled
 53 * 1 : enables assert() only, no display
 54 * 2 : reserved, for currently active debug path
 55 * 3 : events once per object lifetime (CCtx, CDict, etc.)
 56 * 4 : events once per frame
 57 * 5 : events once per block
 58 * 6 : events once per sequence (verbose)
 59 * 7+: events at every position (*very* verbose)
 60 *
 61 * It's generally inconvenient to output traces > 5.
 62 * In which case, it's possible to selectively trigger high verbosity levels
 63 * by modifying g_debug_level.
 64 */
 65
 66#if (DEBUGLEVEL>=1)
 67#  define ZSTD_DEPS_NEED_ASSERT
 68#  include "zstd_deps.h"
 69#else
 70#  ifndef assert   /* assert may be already defined, due to prior #include <assert.h> */
 71#    define assert(condition) ((void)0)   /* disable assert (default) */
 72#  endif
 73#endif
 74
 75#if (DEBUGLEVEL>=2)
 76#  define ZSTD_DEPS_NEED_IO
 77#  include "zstd_deps.h"
 78extern int g_debuglevel; /* the variable is only declared,
 79                            it actually lives in debug.c,
 80                            and is shared by the whole process.
 81                            It's not thread-safe.
 82                            It's useful when enabling very verbose levels
 83                            on selective conditions (such as position in src) */
 84
 85#  define RAWLOG(l, ...)                   \
 86    do {                                   \
 87        if (l<=g_debuglevel) {             \
 88            ZSTD_DEBUG_PRINT(__VA_ARGS__); \
 89        }                                  \
 90    } while (0)
 91
 92#define STRINGIFY(x) #x
 93#define TOSTRING(x) STRINGIFY(x)
 94#define LINE_AS_STRING TOSTRING(__LINE__)
 95
 96#  define DEBUGLOG(l, ...)                               \
 97    do {                                                 \
 98        if (l<=g_debuglevel) {                           \
 99            ZSTD_DEBUG_PRINT(__FILE__ ":" LINE_AS_STRING ": " __VA_ARGS__); \
100            ZSTD_DEBUG_PRINT(" \n");                     \
101        }                                                \
102    } while (0)
103#else
104#  define RAWLOG(l, ...)   do { } while (0)    /* disabled */
105#  define DEBUGLOG(l, ...) do { } while (0)    /* disabled */
106#endif
107
108#endif /* DEBUG_H_12987983217 */