gdbsupport/common-debug.h

   1 /* Declarations for debug printing functions.
   2
   3    Copyright (C) 2014-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef COMMON_COMMON_DEBUG_H
  21 #define COMMON_COMMON_DEBUG_H
  22
  23 /* Set to true to enable debugging of hardware breakpoint/
  24    watchpoint support code.  */
  25
  26 extern bool show_debug_regs;
  27
  28 /* Print a formatted message to the appropriate channel for
  29    debugging output for the client.  */
  30
  31 extern void debug_printf (const char *format, ...)
  32      ATTRIBUTE_PRINTF (1, 2);
  33
  34 /* Print a formatted message to the appropriate channel for
  35    debugging output for the client.  This function must be
  36    provided by the client.  */
  37
  38 extern void debug_vprintf (const char *format, va_list ap)
  39      ATTRIBUTE_PRINTF (1, 0);
  40
  41 /* Print a debug statement prefixed with the module and function name, and
  42    with a newline at the end.  */
  43
  44 extern void ATTRIBUTE_PRINTF (3, 4) debug_prefixed_printf
  45   (const char *module, const char *func, const char *format, ...);
  46
  47 /* Print a debug statement prefixed with the module and function name, and
  48    with a newline at the end.  */
  49
  50 extern void ATTRIBUTE_PRINTF (3, 0) debug_prefixed_vprintf
  51   (const char *module, const char *func, const char *format, va_list args);
  52
  53 /* Helper to define "_debug_print" macros.
  54
  55    DEBUG_ENABLED_COND is an expression that evaluates to true if the debugging
  56    statement is enabled and should be printed.
  57
  58    The other arguments, as well as the name of the current function, are
  59    forwarded to debug_prefixed_printf.  */
  60
  61 #define debug_prefixed_printf_cond(debug_enabled_cond, module, fmt, ...) \
  62   do \
  63     { \
  64       if (debug_enabled_cond) \
  65         debug_prefixed_printf (module, __func__, fmt, ##__VA_ARGS__); \
  66     } \
  67   while (0)
  68
  69 /* Nesting depth of scoped_debug_start_end objects.  */
  70
  71 extern int debug_print_depth;
  72
  73 /* Print a message on construction and destruction, to denote the start and end
  74    of an operation.  Increment DEBUG_PRINT_DEPTH on construction and decrement
  75    it on destruction, such that nested debug statements will be printed with
  76    an indent and appear "inside" this one.  */
  77
  78 struct scoped_debug_start_end
  79 {
  80   /* DEBUG_ENABLED is a reference to a variable that indicates whether debugging
  81      is enabled, so if the debug statements should be printed.  Is is read
  82      separately at construction and destruction, such that the start statement
  83      could be printed but not the end statement, or vice-versa.
  84
  85      MODULE and FUNC are forwarded to debug_prefixed_printf.
  86
  87      START_MSG and END_MSG are the statements to print on construction and
  88      destruction, respectively.  */
  89
  90   scoped_debug_start_end (bool &debug_enabled, const char *module,
  91                           const char *func, const char *start_msg,
  92                           const char *end_msg)
  93     : m_debug_enabled (debug_enabled),
  94       m_module (module),
  95       m_func (func),
  96       m_end_msg (end_msg)
  97   {
  98     if (m_debug_enabled)
  99       {
 100         debug_prefixed_printf (m_module, m_func, "%s", start_msg);
 101         ++debug_print_depth;
 102         m_must_decrement_print_depth = true;
 103       }
 104   }
 105
 106   DISABLE_COPY_AND_ASSIGN (scoped_debug_start_end);
 107
 108   ~scoped_debug_start_end ()
 109   {
 110     if (m_must_decrement_print_depth)
 111       {
 112         gdb_assert (debug_print_depth > 0);
 113         --debug_print_depth;
 114       }
 115
 116     if (m_debug_enabled)
 117       {
 118         debug_prefixed_printf (m_module, m_func, "%s", m_end_msg);
 119       }
 120   }
 121
 122 private:
 123   bool &m_debug_enabled;
 124   const char *m_module;
 125   const char *m_func;
 126   const char *m_end_msg;
 127
 128   /* This is used to handle the case where debugging is enabled during
 129      construction but not during destruction, or vice-versa.  We want to make
 130      sure there are as many increments are there are decrements.  */
 131
 132   bool m_must_decrement_print_depth = false;
 133 };
 134
 135 /* Helper to define a module-specific start/end debug macro.  */
 136
 137 #define scoped_debug_start_end(debug_enabled, module, msg) \
 138   scoped_debug_start_end CONCAT(scoped_debug_start_end, __LINE__) \
 139     (debug_enabled, module, __func__, "start: " msg, "end: " msg)
 140
 141 /* Helper to define a module-specific enter/exit debug macro.  This is a special
 142    case of `scoped_debug_start_end` where the start and end messages are "enter"
 143    and "exit", to denote entry and exit of a function.  */
 144
 145 #define scoped_debug_enter_exit(debug_enabled, module) \
 146   scoped_debug_start_end CONCAT(scoped_debug_start_end, __LINE__) \
 147     (debug_enabled, module, __func__, "enter", "exit")
 148
 149 #endif /* COMMON_COMMON_DEBUG_H */