trace: remove the TraceEventID and TraceEventVCPUID enums

The TraceEventID and TraceEventVCPUID enums constants are
no longer actually used for anything critical.

The TRACE_EVENT_COUNT limit is used to determine the size
of the TraceEvents array, and can be removed if we just
NULL terminate the array instead.

The TRACE_VCPU_EVENT_COUNT limit is used as a magic value
for marking non-vCPU events, and also for declaring the
size of the trace dstate mask in the CPUState struct.
The former usage can be replaced by a dedicated constant
TRACE_EVENT_VCPU_NONE, defined as (uint32_t)-1. For the
latter usage, we can simply define a constant for the
number of VCPUs, avoiding the need for the full enum.

The only other usages of the enum values can be replaced
by accesing the id/vcpu_id fields via the named TraceEvent
structs.

Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-11-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

4 files changed, 16 insertions, 26 deletions

diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py
index 1bccada..1114e35 100644
--- a/scripts/tracetool/backend/simple.py
+++ b/scripts/tracetool/backend/simple.py
@@ -80,11 +80,11 @@ def generate_c(event):
         '        return;',
         '    }',
         '',
-        '    if (trace_record_start(&rec, %(event_id)s, %(size_str)s)) {',
+        '    if (trace_record_start(&rec, %(event_obj)s.id, %(size_str)s)) {',
         '        return; /* Trace Buffer Full, Event Dropped ! */',
         '    }',
         cond=cond,
-        event_id=event_id,
+        event_obj=event.api(event.QEMU_EVENT),
         size_str=sizestr)
 
     if len(event.args) > 0:
diff --git a/scripts/tracetool/format/events_c.py b/scripts/tracetool/format/events_c.py
index a97054f..40ae395 100644
--- a/scripts/tracetool/format/events_c.py
+++ b/scripts/tracetool/format/events_c.py
@@ -28,11 +28,16 @@ def generate(events, backend):
     for e in events:
         out('uint16_t %s;' % e.api(e.QEMU_DSTATE))
 
+    next_id = 0
+    next_vcpu_id = 0
     for e in events:
+        id = next_id
+        next_id += 1
         if "vcpu" in e.properties:
-            vcpu_id = "TRACE_VCPU_" + e.name.upper()
+            vcpu_id = next_vcpu_id
+            next_vcpu_id += 1
         else:
-            vcpu_id = "TRACE_VCPU_EVENT_COUNT"
+            vcpu_id = "TRACE_VCPU_EVENT_NONE"
         out('TraceEvent %(event)s = {',
             '    .id = %(id)s,',
             '    .vcpu_id = %(vcpu_id)s,',
@@ -41,16 +46,17 @@ def generate(events, backend):
             '    .dstate = &%(dstate)s ',
             '};',
             event = e.api(e.QEMU_EVENT),
-            id = "TRACE_" + e.name.upper(),
+            id = id,
             vcpu_id = vcpu_id,
             name = e.name,
             sstate = "TRACE_%s_ENABLED" % e.name.upper(),
             dstate = e.api(e.QEMU_DSTATE))
 
-    out('TraceEvent *trace_events[TRACE_EVENT_COUNT] = {')
+    out('TraceEvent *trace_events[] = {')
 
     for e in events:
         out('    &%(event)s,', event = e.api(e.QEMU_EVENT))
 
-    out('};',
+    out('  NULL,',
+        '};',
         '')
diff --git a/scripts/tracetool/format/events_h.py b/scripts/tracetool/format/events_h.py
index 80a66c5..ca6d730 100644
--- a/scripts/tracetool/format/events_h.py
+++ b/scripts/tracetool/format/events_h.py
@@ -29,27 +29,12 @@ def generate(events, backend):
         out('extern TraceEvent %(event)s;',
             event = e.api(e.QEMU_EVENT))
 
-    # event identifiers
-    out('typedef enum {')
-
-    for e in events:
-        out('    TRACE_%s,' % e.name.upper())
-
-    out('    TRACE_EVENT_COUNT',
-        '} TraceEventID;')
-
     for e in events:
         out('extern uint16_t %s;' % e.api(e.QEMU_DSTATE))
 
-    # per-vCPU event identifiers
-    out('typedef enum {')
-
-    for e in events:
-        if "vcpu" in e.properties:
-            out('    TRACE_VCPU_%s,' % e.name.upper())
+    numvcpu = len([e for e in events if "vcpu" in e.properties])
 
-    out('    TRACE_VCPU_EVENT_COUNT',
-        '} TraceEventVCPUID;')
+    out("#define TRACE_VCPU_EVENT_COUNT %d" % numvcpu)
 
     # static state
     for e in events:
diff --git a/scripts/tracetool/format/h.py b/scripts/tracetool/format/h.py
index 3763e9a..64a6680 100644
--- a/scripts/tracetool/format/h.py
+++ b/scripts/tracetool/format/h.py
@@ -32,8 +32,7 @@ def generate(events, backend):
         if "vcpu" in e.properties:
             trace_cpu = next(iter(e.args))[1]
             cond = "trace_event_get_vcpu_state(%(cpu)s,"\
-                   " TRACE_%(id)s,"\
-                   " TRACE_VCPU_%(id)s)"\
+                   " TRACE_%(id)s)"\
                    % dict(
                        cpu=trace_cpu,
                        id=e.name.upper())