erts: Implement tracer modules

Add the possibility to use modules as trace data receivers. The functions
in the module have to be nifs as otherwise complex trace probes will be
very hard to handle (complex means trace probes for ports for example).

This commit changes the way that the ptab->tracer field works from always
being an immediate, to now be NIL if no tracer is present or else be
the tuple {TracerModule, TracerState} where TracerModule is an atom that
is later used to lookup the appropriate tracer callbacks to call and
TracerState is just passed to the tracer callback. The default process and
port tracers have been rewritten to use the new API.

This commit also changes the order which trace messages are delivered to the
potential tracer process. Any enif_send done in a tracer module may be delayed
indefinitely because of lock order issues. If a message is delayed any other
trace message send from that process is also delayed so that order is preserved
for each traced entity. This means that for some trace events (i.e. send/receive)
the events may come in an unintuitive order (receive before send) to the
trace receiver. Timestamps are taken when the trace message is generated so
trace messages from differented processes may arrive with the timestamp
out of order.

Both the erlang:trace and seq_trace:set_system_tracer accept the new tracer
module tracers and also the backwards compatible arguments.

OTP-10267

1 files changed, 59 insertions, 19 deletions

diff --git a/erts/emulator/beam/erl_trace.h b/erts/emulator/beam/erl_trace.h
index 1da27ee128..61f82a6b93 100644
--- a/erts/emulator/beam/erl_trace.h
+++ b/erts/emulator/beam/erl_trace.h
@@ -46,6 +46,8 @@
 #define ERTS_SEQTFLGS2TSTYPE(SEQTFLGS)				\
     ((int) (((SEQTFLGS) >> ERTS_SEQ_TRACE_FLAGS_TS_TYPE_SHIFT)	\
 	    & ERTS_TRACE_TS_TYPE_MASK))
+#define ERTS_SEQTFLGS2TFLGS(SEQTFLGS)                                   \
+    (ERTS_SEQTFLGS2TSTYPE(SEQTFLGS) << ERTS_TRACE_FLAGS_TS_TYPE_SHIFT)
 
 #endif /* ERL_TRACE_H__FLAGS__ */
 
@@ -62,15 +64,16 @@ void erts_system_profile_clear(Process *c_p);
 /* erl_trace.c */
 void erts_init_trace(void);
 void erts_trace_check_exiting(Eterm exiting);
-Eterm erts_set_system_seq_tracer(Process *c_p,
-				 ErtsProcLocks c_p_locks,
-				 Eterm new);
-Eterm erts_get_system_seq_tracer(void);
-void erts_change_default_tracing(int setflags, Uint *flagsp, Eterm *tracerp);
-void erts_get_default_tracing(Uint *flagsp, Eterm *tracerp);
+ErtsTracer erts_set_system_seq_tracer(Process *c_p,
+                                      ErtsProcLocks c_p_locks,
+                                      ErtsTracer new);
+ErtsTracer erts_get_system_seq_tracer(void);
+void erts_change_default_tracing(int setflags, Uint *flagsp,
+                                 const ErtsTracer tracerp);
+void erts_get_default_tracing(Uint *flagsp, ErtsTracer *tracerp);
 void erts_set_system_monitor(Eterm monitor);
 Eterm erts_get_system_monitor(void);
-int erts_is_tracer_proc_valid(Process* p);
+int erts_is_tracer_valid(Process* p);
 
 #ifdef ERTS_SMP
 void erts_check_my_tracer_proc(Process *);
@@ -83,22 +86,22 @@ void erts_foreach_sys_msg_in_q(void (*func)(Eterm,
 void erts_queue_error_logger_message(Eterm, Eterm, ErlHeapFragment *);
 #endif
 
-void erts_send_sys_msg_proc(Eterm, Eterm, Eterm, ErlHeapFragment *);
 void trace_send(Process*, Eterm, Eterm);
-void trace_receive(Process*, Eterm);
-Uint32 erts_call_trace(Process *p, BeamInstr mfa[], struct binary *match_spec, Eterm* args,
-		       int local, Eterm *tracer_pid);
-void erts_trace_return(Process* p, BeamInstr* fi, Eterm retval, Eterm *tracer_pid);
+void trace_receive(Process *, Eterm);
+Uint32 erts_call_trace(Process *p, BeamInstr mfa[], struct binary *match_spec,
+                       Eterm* args, int local, ErtsTracer *tracer);
+void erts_trace_return(Process* p, BeamInstr* fi, Eterm retval,
+                       ErtsTracer *tracer);
 void erts_trace_exception(Process* p, BeamInstr mfa[], Eterm class, Eterm value,
-			  Eterm *tracer);
+                          ErtsTracer *tracer);
 void erts_trace_return_to(Process *p, BeamInstr *pc);
-void trace_sched(Process*, Eterm);
-void trace_proc(Process*, Process*, Eterm, Eterm);
+void trace_sched(Process*, ErtsProcLocks, Eterm);
+void trace_proc(Process*, ErtsProcLocks, Process*, Eterm, Eterm);
 void trace_proc_spawn(Process*, Eterm pid, Eterm mod, Eterm func, Eterm args);
 void save_calls(Process *p, Export *);
 void trace_gc(Process *p, Eterm what);
 /* port tracing */
-void trace_virtual_sched(Process*, Eterm);
+void trace_virtual_sched(Process*, ErtsProcLocks, Eterm);
 void trace_sched_ports(Port *pp, Eterm);
 void trace_sched_ports_where(Port *pp, Eterm, Eterm);
 void trace_port(Port *, Eterm what, Eterm data);
@@ -121,7 +124,7 @@ void monitor_large_heap(Process *p);
 void monitor_generic(Process *p, Eterm type, Eterm spec);
 Uint erts_trace_flag2bit(Eterm flag);
 int erts_trace_flags(Eterm List, 
-		 Uint *pMask, Eterm *pTracer, int *pCpuTimestamp);
+		 Uint *pMask, ErtsTracer *pTracer, int *pCpuTimestamp);
 Eterm erts_bif_trace(int bif_index, Process* p, Eterm* args, BeamInstr *I);
 
 #ifdef ERTS_SMP
@@ -161,15 +164,52 @@ int erts_set_trace_pattern(Process*p, Eterm* mfa, int specified,
 			   struct binary* match_prog_set,
 			   struct binary *meta_match_prog_set,
 			   int on, struct trace_pattern_flags,
-			   Eterm meta_tracer_pid, int is_blocking);
+			   ErtsTracer meta_tracer, int is_blocking);
 void
 erts_get_default_trace_pattern(int *trace_pattern_is_on,
 			       struct binary **match_spec,
 			       struct binary **meta_match_spec,
 			       struct trace_pattern_flags *trace_pattern_flags,
-			       Eterm *meta_tracer_pid);
+			       ErtsTracer *meta_tracer);
 int erts_is_default_trace_enabled(void);
 void erts_bif_trace_init(void);
 int erts_finish_breakpointing(void);
 
+/* Nif tracer functions */
+int erts_is_tracer_proc_enabled(Process *c_p, ErtsProcLocks c_p_locks,
+                                ErtsPTabElementCommon *t_p);
+int erts_is_tracer_enabled(Process *c_p, const ErtsTracer tracer);
+Eterm erts_tracer_to_term(Process *p, ErtsTracer tracer);
+ErtsTracer erts_term_to_tracer(Eterm prefix, Eterm term);
+void erts_tracer_replace(ErtsPTabElementCommon *t_p,
+                         const ErtsTracer new_tracer);
+void erts_tracer_update(ErtsTracer *tracer, const ErtsTracer new_tracer);
+int erts_tracer_nif_clear(void);
+
+#define erts_tracer_update(t,n) do { if (*(t) != (n)) erts_tracer_update(t,n); } while(0)
+#define ERTS_TRACER_CLEAR(t) erts_tracer_update(t, erts_tracer_nil)
+
+static const ErtsTracer
+ERTS_DECLARE_DUMMY(erts_tracer_true) = am_true;
+
+static const ErtsTracer
+ERTS_DECLARE_DUMMY(erts_tracer_nil) = NIL;
+
+#define ERTS_TRACER_COMPARE(t1, t2)                     \
+    (EQ((t1), (t2)))
+
+#define ERTS_TRACER_IS_NIL(t1) ERTS_TRACER_COMPARE(t1, erts_tracer_nil)
+
+#define IS_TRACER_VALID(tracer)                                         \
+    (ERTS_TRACER_COMPARE(tracer,erts_tracer_true)                       \
+     || ERTS_TRACER_IS_NIL(tracer)                                      \
+     || (is_list(tracer) && is_atom(CAR(list_val(tracer)))))
+
+#define ERTS_TRACER_FROM_ETERM(termp) \
+    ((ErtsTracer*)(termp))
+
+#define ERTS_TRACER_PROC_IS_ENABLED(PROC)                               \
+    (!ERTS_TRACER_IS_NIL(ERTS_TRACER(PROC))                             \
+     && erts_is_tracer_proc_enabled(PROC, ERTS_PROC_LOCK_MAIN, &(PROC)->common))
+
 #endif /* ERL_TRACE_H__ */