gdb: introduce scoped debug prints

[deliverable/binutils-gdb.git] / gdbsupport / common-debug.h

diff --git a/gdbsupport/common-debug.h b/gdbsupport/common-debug.h
index afb427e18005088efd1d7093407df891f2d87e11..f3137870ffc3743b620c5d86e3b60cba344dfe42 100644 (file)
--- a/gdbsupport/common-debug.h
+++ b/gdbsupport/common-debug.h
@@ -1,6 +1,6 @@
 /* Declarations for debug printing functions.
 
-   Copyright (C) 2014-2020 Free Software Foundation, Inc.
+   Copyright (C) 2014-2021 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -41,7 +41,109 @@ extern void debug_vprintf (const char *format, va_list ap)
 /* Print a debug statement prefixed with the module and function name, and
    with a newline at the end.  */
 
+extern void ATTRIBUTE_PRINTF (3, 4) debug_prefixed_printf
+  (const char *module, const char *func, const char *format, ...);
+
+/* Print a debug statement prefixed with the module and function name, and
+   with a newline at the end.  */
+
 extern void ATTRIBUTE_PRINTF (3, 0) debug_prefixed_vprintf
   (const char *module, const char *func, const char *format, va_list args);
 
+/* Helper to define "_debug_print" macros.
+
+   DEBUG_ENABLED_COND is an expression that evaluates to true if the debugging
+   statement is enabled and should be printed.
+
+   The other arguments, as well as the name of the current function, are
+   forwarded to debug_prefixed_printf.  */
+
+#define debug_prefixed_printf_cond(debug_enabled_cond, module, fmt, ...) \
+  do \
+    { \
+      if (debug_enabled_cond) \
+       debug_prefixed_printf (module, __func__, fmt, ##__VA_ARGS__); \
+    } \
+  while (0)
+
+/* Nesting depth of scoped_debug_start_end objects.  */
+
+extern int debug_print_depth;
+
+/* Print a message on construction and destruction, to denote the start and end
+   of an operation.  Increment DEBUG_PRINT_DEPTH on construction and decrement
+   it on destruction, such that nested debug statements will be printed with
+   an indent and appear "inside" this one.  */
+
+struct scoped_debug_start_end
+{
+  /* DEBUG_ENABLED is a reference to a variable that indicates whether debugging
+     is enabled, so if the debug statements should be printed.  Is is read
+     separately at construction and destruction, such that the start statement
+     could be printed but not the end statement, or vice-versa.
+
+     MODULE and FUNC are forwarded to debug_prefixed_printf.
+
+     START_MSG and END_MSG are the statements to print on construction and
+     destruction, respectively.  */
+
+  scoped_debug_start_end (bool &debug_enabled, const char *module,
+                         const char *func, const char *start_msg,
+                         const char *end_msg)
+    : m_debug_enabled (debug_enabled),
+      m_module (module),
+      m_func (func),
+      m_end_msg (end_msg)
+  {
+    if (m_debug_enabled)
+      {
+       debug_prefixed_printf (m_module, m_func, "%s", start_msg);
+       ++debug_print_depth;
+       m_must_decrement_print_depth = true;
+      }
+  }
+
+  DISABLE_COPY_AND_ASSIGN (scoped_debug_start_end);
+
+  ~scoped_debug_start_end ()
+  {
+    if (m_must_decrement_print_depth)
+      {
+       gdb_assert (debug_print_depth > 0);
+       --debug_print_depth;
+      }
+
+    if (m_debug_enabled)
+      {
+       debug_prefixed_printf (m_module, m_func, "%s", m_end_msg);
+      }
+  }
+
+private:
+  bool &m_debug_enabled;
+  const char *m_module;
+  const char *m_func;
+  const char *m_end_msg;
+
+  /* This is used to handle the case where debugging is enabled during
+     construction but not during destruction, or vice-versa.  We want to make
+     sure there are as many increments are there are decrements.  */
+
+  bool m_must_decrement_print_depth = false;
+};
+
+/* Helper to define a module-specific start/end debug macro.  */
+
+#define scoped_debug_start_end(debug_enabled, module, msg) \
+  scoped_debug_start_end CONCAT(scoped_debug_start_end, __LINE__) \
+    (debug_enabled, module, __func__, "start: " msg, "end: " msg)
+
+/* Helper to define a module-specific enter/exit debug macro.  This is a special
+   case of `scoped_debug_start_end` where the start and end messages are "enter"
+   and "exit", to denote entry and exit of a function.  */
+
+#define scoped_debug_enter_exit(debug_enabled, module) \
+  scoped_debug_start_end CONCAT(scoped_debug_start_end, __LINE__) \
+    (debug_enabled, module, __func__, "enter", "exit")
+
 #endif /* COMMON_COMMON_DEBUG_H */