trace: [simple] Port to generic event information and new control interface

The backend is forced to dump event numbers using 64 bits, as TraceEventID is
an enum.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

scripts/tracetool/backend/simple.py

@@ -28,17 +28,10 @@ def is_string(arg):
 
 def c(events):
     out('#include "trace.h"',
+        '#include "trace/control.h"',
         '#include "trace/simple.h"',
         '',
-        'TraceEvent trace_list[] = {')
-
-    for e in events:
-        out('{.tp_name = "%(name)s", .state=0},',
-            name = e.name,
-            )
-
-    out('};',
-        '')
+        )
 
     for num, event in enumerate(events):
         out('void trace_%(name)s(%(args)s)',
@@ -63,7 +56,9 @@ def c(events):
 
 
         out('',
-            '    if (!trace_list[%(event_id)s].state) {',
+            '    TraceEvent *eventp = trace_event_id(%(event_id)s);',
+            '    bool _state = trace_event_get_state_dynamic(eventp);',
+            '    if (!_state) {',
             '        return;',
             '    }',
             '',
@@ -106,6 +101,3 @@ def h(events):
             name = event.name,
             args = event.args,
             )
-    out('')
-    out('#define NR_TRACE_EVENTS %d' % len(events))
-    out('extern TraceEvent trace_list[NR_TRACE_EVENTS];')

trace/simple.c

@@ -218,6 +218,7 @@ int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasi
 {
     unsigned int idx, rec_off, old_idx, new_idx;
     uint32_t rec_len = sizeof(TraceRecord) + datasize;
+    uint64_t event_u64 = event;
     uint64_t timestamp_ns = get_clock();
 
     do {
@@ -235,7 +236,7 @@ int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasi
     idx = old_idx % TRACE_BUF_LEN;
 
     rec_off = idx;
-    rec_off = write_to_buffer(rec_off, &event, sizeof(event));
+    rec_off = write_to_buffer(rec_off, &event_u64, sizeof(event_u64));
     rec_off = write_to_buffer(rec_off, &timestamp_ns, sizeof(timestamp_ns));
     rec_off = write_to_buffer(rec_off, &rec_len, sizeof(rec_len));
 
@@ -359,38 +360,16 @@ void trace_print_events(FILE *stream, fprintf_function stream_printf)
 {
     unsigned int i;
 
-    for (i = 0; i < NR_TRACE_EVENTS; i++) {
+    for (i = 0; i < trace_event_count(); i++) {
+        TraceEvent *ev = trace_event_id(i);
         stream_printf(stream, "%s [Event ID %u] : state %u\n",
-                      trace_list[i].tp_name, i, trace_list[i].state);
+                      trace_event_get_name(ev), i, trace_event_get_state_dynamic(ev));
     }
 }
 
-bool trace_event_set_state(const char *name, bool state)
+void trace_event_set_state_dynamic_backend(TraceEvent *ev, bool state)
 {
-    unsigned int i;
-    unsigned int len;
-    bool wildcard = false;
-    bool matched = false;
-
-    len = strlen(name);
-    if (len > 0 && name[len - 1] == '*') {
-        wildcard = true;
-        len -= 1;
-    }
-    for (i = 0; i < NR_TRACE_EVENTS; i++) {
-        if (wildcard) {
-            if (!strncmp(trace_list[i].tp_name, name, len)) {
-                trace_list[i].state = state;
-                matched = true;
-            }
-            continue;
-        }
-        if (!strcmp(trace_list[i].tp_name, name)) {
-            trace_list[i].state = state;
-            return true;
-        }
-    }
-    return matched;
+    ev->dstate = state;
 }
 
 /* Helper function to create a thread with signals blocked.  Use glib's

trace/simple.h

@@ -15,12 +15,8 @@
 #include <stdbool.h>
 #include <stdio.h>
 
-typedef uint64_t TraceEventID;
+#include "trace/generated-events.h"
 
-typedef struct {
-    const char *tp_name;
-    bool state;
-} TraceEvent;
 
 void st_print_trace_file_status(FILE *stream, fprintf_function stream_printf);
 void st_set_trace_file_enabled(bool enable);