gdb: factor out debug_prefixed_printf_cond

The same pattern happens often to define a "debug_printf" macro:

    #define displaced_debug_printf(fmt, ...) \
      do \
        { \
          if (debug_displaced) \
    	debug_prefixed_printf ("displaced", __func__, fmt, ##__VA_ARGS__); \
        } \
      while (0)

Move this pattern behind a helper macro, debug_prefixed_printf_cond and
update the existing macros to use it.

gdb/ChangeLog:

	* displaced-stepping.h (displaced_debug_printf): Use
	debug_prefixed_printf_cond.
	* dwarf2/read.c (dwarf_read_debug_printf): Likewise.
	(dwarf_read_debug_printf_v): Likewise.
	* infrun.h (infrun_debug_printf): Likewise.
	* linux-nat.c (linux_nat_debug_printf): Likewise.

gdbsupport/ChangeLog:

	* common-debug.h (debug_prefixed_printf_cond): New.
	* event-loop.h (event_loop_debug_printf): Use
	debug_prefixed_printf_cond.

Change-Id: I1ff48b98b8d1cc405d1c7e8da8ceadf4e3a17f99

gdb/ChangeLog

@@ -1,3 +1,12 @@
+2020-12-11  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* displaced-stepping.h (displaced_debug_printf): Use
+	debug_prefixed_printf_cond.
+	* dwarf2/read.c (dwarf_read_debug_printf): Likewise.
+	(dwarf_read_debug_printf_v): Likewise.
+	* infrun.h (infrun_debug_printf): Likewise.
+	* linux-nat.c (linux_nat_debug_printf): Likewise.
+
 2020-12-11  Tom Tromey  <tom@tromey.com>
 
 	* p-exp.y (intvar): Remove global.

gdb/displaced-stepping.h

@@ -33,12 +33,7 @@ extern bool debug_displaced;
 /* Print a "displaced" debug statement.  */
 
 #define displaced_debug_printf(fmt, ...) \
-  do \
-    { \
-      if (debug_displaced) \
-	debug_prefixed_printf ("displaced", __func__, fmt, ##__VA_ARGS__); \
-    } \
-  while (0)
+  debug_prefixed_printf_cond (debug_displaced, "displaced",fmt, ##__VA_ARGS__)
 
 enum displaced_step_prepare_status
 {

gdb/dwarf2/read.c

@@ -96,22 +96,14 @@ static unsigned int dwarf_read_debug = 0;
 /* Print a "dwarf-read" debug statement if dwarf_read_debug is >= 1.  */
 
 #define dwarf_read_debug_printf(fmt, ...) \
-  do \
-    { \
-      if (dwarf_read_debug >= 1) \
-	debug_prefixed_printf ("dwarf-read", __func__, fmt, ##__VA_ARGS__); \
-    } \
-  while (0)
+  debug_prefixed_printf_cond (dwarf_read_debug >= 1, "dwarf-read", fmt, \
+			      ##__VA_ARGS__)
 
 /* Print a "dwarf-read" debug statement if dwarf_read_debug is >= 2.  */
 
 #define dwarf_read_debug_printf_v(fmt, ...) \
-  do \
-    { \
-      if (dwarf_read_debug >= 2) \
-	debug_prefixed_printf ("dwarf-read", __func__, fmt, ##__VA_ARGS__); \
-    } \
-  while (0)
+  debug_prefixed_printf_cond (dwarf_read_debug >= 2, "dwarf-read", fmt, \
+			      ##__VA_ARGS__)
 
 /* When non-zero, dump DIEs after they are read in.  */
 static unsigned int dwarf_die_debug = 0;

gdb/infrun.h

@@ -34,12 +34,7 @@ extern unsigned int debug_infrun;
 /* Print an "infrun" debug statement.  */
 
 #define infrun_debug_printf(fmt, ...) \
-  do \
-    { \
-      if (debug_infrun) \
-	debug_prefixed_printf ("infrun", __func__, fmt, ##__VA_ARGS__); \
-    } \
-  while (0)
+  debug_prefixed_printf_cond (debug_infrun, "infrun",fmt, ##__VA_ARGS__)
 
 /* Nonzero if we want to give control to the user when we're notified
    of shared library events by the dynamic linker.  */

gdb/linux-nat.c

@@ -202,12 +202,7 @@ show_debug_linux_nat (struct ui_file *file, int from_tty,
 /* Print a linux-nat debug statement.  */
 
 #define linux_nat_debug_printf(fmt, ...) \
-  do \
-    { \
-      if (debug_linux_nat) \
-	debug_prefixed_printf ("linux-nat", __func__, fmt, ##__VA_ARGS__); \
-    } \
-  while (0)
+  debug_prefixed_printf_cond (debug_linux_nat, "linux-nat", fmt, ##__VA_ARGS__)
 
 struct simple_pid_list
 {

gdbsupport/ChangeLog

@@ -1,3 +1,9 @@
+2020-12-11  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* common-debug.h (debug_prefixed_printf_cond): New.
+	* event-loop.h (event_loop_debug_printf): Use
+	debug_prefixed_printf_cond.
+
 2020-12-08  Alexander Fedotov  <alfedotov@gmail.com>
 
 	* pathstuff.cc (get_standard_cache_dir): Use LOCALAPPDATA environment

gdbsupport/common-debug.h

@@ -50,4 +50,21 @@ extern void ATTRIBUTE_PRINTF (3, 4) debug_prefixed_printf
 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)
+
 #endif /* COMMON_COMMON_DEBUG_H */

gdbsupport/event-loop.h

@@ -129,12 +129,8 @@ extern debug_event_loop_kind debug_event_loop;
 /* Print an "event loop" debug statement.  */
 
 #define event_loop_debug_printf(fmt, ...) \
-  do \
-    { \
-      if (debug_event_loop != debug_event_loop_kind::OFF) \
-	debug_prefixed_printf ("event-loop", __func__, fmt, ##__VA_ARGS__); \
-    } \
-  while (0)
+  debug_prefixed_printf_cond (debug_event_loop != debug_event_loop_kind::OFF, \
+			      "event-loop", fmt, ##__VA_ARGS__)
 
 /* Print an "event loop" debug statement that is know to come from a UI-related
    event (e.g. calling the event handler for the fd of the CLI).  */