Make XLap opt-in

- Make X-Lap disabled by default
- Enable X-Lap if the macro XLAP is defined

xlap.c

+#define XLAP
 #include "xlap.h"
 
 #include <stdatomic.h>

xlap.h

@@ -81,17 +81,25 @@ typedef struct XlapTimestampTableRow {
 /*
  * Table that stores timestamp table rows
  */
-typedef struct XlapTimestampTable {
-	XlapTimestampTableRow rows[TS_ROWS];
-} XlapTimestampTable;
+#ifdef XLAP
+	typedef struct XlapTimestampTable {
+		XlapTimestampTableRow rows[TS_ROWS];
+	} XlapTimestampTable;
+#else /* XLAP */
+	typedef char XlapTimestampTable;
+#endif
 
 /*
  * Dummy data structure to store a single timestamp table row.
  */
-typedef struct XlapTimestampPlaceholder {
-	_Atomic(XlapTimestampTable *) tstable[1];
-	XlapTimestampTableRow rows[1];
-} XlapTimestampPlaceholder;
+#ifdef XLAP
+	typedef struct XlapTimestampPlaceholder {
+		_Atomic(XlapTimestampTable *) tstable[1];
+		XlapTimestampTableRow rows[1];
+	} XlapTimestampPlaceholder;
+#else /* XLAP */
+	typedef char XlapTimestampPlaceholder;
+#endif
 
 /*
  * update the clock value of a timestamp
@@ -99,9 +107,19 @@ typedef struct XlapTimestampPlaceholder {
  * This macro will cause a SIGSEGV if the application does not install a
  * timestamp table to the socket.
  */
-#define XlapTimeStampClock(sck, kind, seqno, id) do { \
-		clock_gettime(CLOCK_MONOTONIC, &atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire)->rows[(seqno) % TS_ROWS].time[ts_##id].actual.t); \
-	} while (0);
+#ifdef XLAP
+#	define XlapTimeStampClock(sck, kind, seqno, id) do { \
+			clock_gettime(CLOCK_MONOTONIC, &atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire)->rows[(seqno) % TS_ROWS].time[ts_##id].actual.t); \
+		} while (0)
+#else /* XLAP */
+#	define XlapTimeStampClock(sck, kind, seqno, id) do { \
+			(void) (sck); \
+			(void) (kind); \
+			(void) (seqno); \
+			(void) (ts_##id); \
+		} while (0)
+#endif
+
 
 /*
  * update the cycle value of a timestamp
@@ -109,42 +127,76 @@ typedef struct XlapTimestampPlaceholder {
  * This macro will cause a SIGSEGV if the application does not install a
  * timestamp table to the socket.
  */
-#define XlapTimeStampCycle(sck, kind, seqno, id) do { \
-		atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire)->rows[(seqno) % TS_ROWS].time[ts_##id].actual.c = __builtin_ia32_rdtsc(); \
-	} while (0);
+#ifdef XLAP
+#	define XlapTimeStampCycle(sck, kind, seqno, id) do { \
+			atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire)->rows[(seqno) % TS_ROWS].time[ts_##id].actual.c = __builtin_ia32_rdtsc(); \
+		} while (0)
+#else /* XLAP */
+#	define XlapTimeStampCycle(sck, kind, seqno, id) do { \
+			(void) (sck); \
+			(void) (kind); \
+			(void) (seqno); \
+			(void) (ts_##id); \
+		} while (0)
+#endif
+
 
 /*
  * install a time stamp table to a socket
  */
-#define XlapTimestampTableInstall(sck, kind, tstp) do { \
-		XlapTimestampTable *__tstp = (tstp); \
-		memset(__tstp, 0, sizeof(XlapTimestampTable)); \
-		atomic_store_explicit(&(sck)->tstable[kind], __tstp, memory_order_release); \
-	} while (0)
+#ifdef XLAP
+#	define XlapTimestampTableInstall(sck, kind, tstp) do { \
+			XlapTimestampTable *__tstp = (tstp); \
+			memset(__tstp, 0, sizeof(XlapTimestampTable)); \
+			atomic_store_explicit(&(sck)->tstable[kind], __tstp, memory_order_release); \
+		} while (0)
+#else /* XLAP */
+#	define XlapTimestampTableInstall(sck, kind, tstp) do { \
+			(void) (sck); \
+			(void) (kind); \
+			(void) (tstp); \
+		} while (0)
+#endif
+
 
 /*
  * print a timestamp dump header
  */
-extern void XlapTimestampTableDumpHeader(FILE *);
+#ifdef XLAP
+	extern void XlapTimestampTableDumpHeader(FILE *);
+#else
+#	define XlapTimestampTableDumpHeader(f) do { \
+			(void) (f); \
+		} while (0)
+#endif
 
 /*
  * dump a timestamp table
  */
-extern void XlapTimestampTableDump(FILE *, XlapTimestampPacketKind, XlapTimestampTable *);
-
-/*
- * use a specific timestamp table
- */
-extern void XlapTimestampTableUse(XlapTimestampTable *);
+#ifdef XLAP
+	extern void XlapTimestampTableDump(FILE *, XlapTimestampPacketKind, XlapTimestampTable *);
+#else
+#	define XlapTimestampTableDump(f, k, t) do { \
+			(void) (f); \
+			(void) (k); \
+			(void) (t); \
+		} while (0)
+#endif
 
 /*
  * intialize a timestamp table placeholder
  */
-#define XlapTimestampPlaceholderInitialize(ph) do { \
-		XlapTimestampPlaceholder *__ph = (ph); \
-		atomic_store_explicit(&__ph->tstable[0], (XlapTimestampTable *) &__ph->rows, memory_order_release); \
-		memset(&__ph->rows, 0x0, sizeof(XlapTimestampTableRow)); \
-	} while (0);
+#ifdef XLAP
+#	define XlapTimestampPlaceholderInitialize(ph) do { \
+			XlapTimestampPlaceholder *__ph = (ph); \
+			atomic_store_explicit(&__ph->tstable[0], (XlapTimestampTable *) &__ph->rows, memory_order_release); \
+			memset(&__ph->rows, 0x0, sizeof(XlapTimestampTableRow)); \
+		} while (0)
+#else
+#	define XlapTimestampPlaceholderInitialize(ph) do { \
+			(void) (ph); \
+		} while (0)
+#endif
 
 /*
  * copy a timestamp table placeholder into an actual timestamp table
@@ -152,14 +204,23 @@ extern void XlapTimestampTableUse(XlapTimestampTable *);
  * Since every timestamp is taken at most once, either the timestamptable or
  * the placeholder value must be zero (for each timestamp).
  */
-#define XlapTimestampPlaceholderUse(sck, kind, seqno, ph) do { \
-		XlapTimestampPlaceholder *__ph = (ph); \
-		XlapTimestampTable       *__ts = atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire); \
-		for (unsigned int __t = 0; __t < ts_count; __t++) { \
-			__ts->rows[seqno % TS_ROWS].time[__t].actual.t.tv_sec  += __ph->rows[0].time[__t].actual.t.tv_sec; \
-			__ts->rows[seqno % TS_ROWS].time[__t].actual.t.tv_nsec += __ph->rows[0].time[__t].actual.t.tv_nsec; \
-			__ts->rows[seqno % TS_ROWS].time[__t].actual.c         += __ph->rows[0].time[__t].actual.c; \
-		} \
-	} while (0)
+#ifdef XLAP
+#	define XlapTimestampPlaceholderUse(sck, kind, seqno, ph) do { \
+			XlapTimestampPlaceholder *__ph = (ph); \
+			XlapTimestampTable       *__ts = atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire); \
+			for (unsigned int __t = 0; __t < ts_count; __t++) { \
+				__ts->rows[seqno % TS_ROWS].time[__t].actual.t.tv_sec  += __ph->rows[0].time[__t].actual.t.tv_sec; \
+				__ts->rows[seqno % TS_ROWS].time[__t].actual.t.tv_nsec += __ph->rows[0].time[__t].actual.t.tv_nsec; \
+				__ts->rows[seqno % TS_ROWS].time[__t].actual.c         += __ph->rows[0].time[__t].actual.c; \
+			} \
+		} while (0)
+#else
+#	define XlapTimestampPlaceholderUse(sck, kind, seqno, ph) do { \
+			(void) (sck); \
+			(void) (kind); \
+			(void) (seqno); \
+			(void) (ph); \
+		} while (0)
+#endif
 
 #endif // XLAP_H