From a818861c6353e2601dadad442acad19fc1c508b7 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 15 Oct 2012 22:07:58 -0400
Subject: [PATCH] callsite: extract instruction pointer from call sites

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 include/lttng/tracepoint-types.h |  5 +++--
 include/lttng/tracepoint.h       | 35 ++++++++++++++++++++------------
 liblttng-ust/ltt-events.c        |  4 +++-
 liblttng-ust/tracepoint.c        |  5 +++--
 4 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/include/lttng/tracepoint-types.h b/include/lttng/tracepoint-types.h
index 27500d40..838446fa 100644
--- a/include/lttng/tracepoint-types.h
+++ b/include/lttng/tracepoint-types.h
@@ -32,11 +32,12 @@ struct tracepoint {
 
 #define TRACEPOINT_CALLSITE_PADDING	16
 struct tracepoint_callsite {
-	const struct tracepoint *tp;
+	const char *name;
 	const char *func;
 	const char *file;
+	void *ip;
 	unsigned int lineno;
 	char padding[TRACEPOINT_CALLSITE_PADDING];
-};
+} __attribute__((packed));
 
 #endif /* _LTTNG_TRACEPOINT_TYPES_H */
diff --git a/include/lttng/tracepoint.h b/include/lttng/tracepoint.h
index 8086b648..61d227d5 100644
--- a/include/lttng/tracepoint.h
+++ b/include/lttng/tracepoint.h
@@ -220,25 +220,34 @@ struct tracepoint_callsite_dlopen tracepoint_callsite_dlopen
 int __tracepoint_callsite_registered
 	__attribute__((weak, visibility("hidden")));
 
+#if (CAA_BITS_PER_LONG == 64)
+#define __TP_ASM_PTR	".quad "
+#else
+#define __TP_ASM_PTR	".long "
+#endif
+
 /*
  * Note: to allow PIC code, we need to allow the linker to update the pointers
  * in the __tracepoints_callsite_ptrs section.
  * Therefore, this section is _not_ const (read-only).
  */
 #define TRACEPOINT_CALLSITE(_provider, _name)					\
-	static struct tracepoint_callsite					\
-		__tracepoint_callsite_##_provider##___##_name			\
-		__attribute__((section("__tracepoint_callsite"))) =		\
-		{								\
-			.tp = &__tracepoint_##_provider##___##_name,		\
-			.func = __func__,					\
-			.file = __FILE__,					\
-			.lineno = __LINE__,					\
-		};								\
-	static struct tracepoint_callsite *					\
-		__tracepoint_callsite_ptr_##_provider##___##_name		\
-		__attribute__((used, section("__tracepoint_callsite_ptrs"))) =	\
-			&__tracepoint_callsite_##_provider##___##_name
+do {										\
+	asm volatile (	".pushsection __tracepoint_callsite, \"aw\"\n\t"	\
+			"1:\n\t"						\
+			__TP_ASM_PTR "%c0, %c1, %c2, 2f\n\t"			\
+			".int %c3\n\t"						\
+			".space 16\n\t"	/* padding */				\
+			".popsection\n\t"					\
+			".pushsection __tracepoint_callsite_ptrs, \"aw\"\n\t"	\
+			__TP_ASM_PTR "1b\n\t"					\
+			".popsection\n\t"					\
+			"2:\n\t"						\
+		: : "i" (#_provider ":" #_name),		 		\
+			"i" (__func__),						\
+			"i" (__FILE__),						\
+			"i" (__LINE__));					\
+} while (0)
 
 /*
  * These weak symbols, the constructor, and destructor take care of
diff --git a/liblttng-ust/ltt-events.c b/liblttng-ust/ltt-events.c
index 2109b8c2..6b9170a0 100644
--- a/liblttng-ust/ltt-events.c
+++ b/liblttng-ust/ltt-events.c
@@ -1016,11 +1016,13 @@ int _ltt_callsite_metadata_statedump(struct ltt_session *session,
 		"callsite {\n"
 		"	name = \"%s\";\n"
 		"	func = \"%s\";\n"
+		"	ip = %p;\n"
 		"	file = \"%s\";\n"
 		"	line = %u;\n"
 		"};\n\n",
-		callsite->tp_cs->tp->name,
+		callsite->tp_cs->name,
 		callsite->tp_cs->func,
+		callsite->tp_cs->ip,
 		callsite->tp_cs->file,
 		callsite->tp_cs->lineno);
 	if (ret)
diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c
index 3abed871..6585daa8 100644
--- a/liblttng-ust/tracepoint.c
+++ b/liblttng-ust/tracepoint.c
@@ -736,9 +736,10 @@ int tracepoint_register_lib_callsite(struct tracepoint_callsite * const *tp_star
 		for (i = 0; i < tp_count; i++) {
 			if (!tp_start[i])	/* Check for dummy */
 				continue;
-			DBG("registered callsite for tracepoint \"%s\" at %s@%s:%u",
-				tp_start[i]->tp->name,
+			DBG("registered callsite for tracepoint \"%s\" at %s@%p:%s:%u",
+				tp_start[i]->name,
 				tp_start[i]->func,
+				tp_start[i]->ip,
 				tp_start[i]->file,
 				tp_start[i]->lineno);
 			real_count++;
-- 
2.34.1