trace: Do not include qom/cpu.h into generated trace.h

docs/devel/tracing.txt explains "since many source files include
trace.h, [the generated trace.h use] a minimum of types and other
header files included to keep the namespace clean and compile times
and dependencies down."

Commit 4815185902 "trace: Add per-vCPU tracing states for events with
the 'vcpu' property" made them all include qom/cpu.h via
control-internal.h.  qom/cpu.h in turn includes about thirty headers.
Ouch.

Per-vCPU tracing is currently not supported in sub-directories'
trace-events.  In other words, qom/cpu.h can only be used in
trace-root.h, not in any trace.h.

Split trace/control-vcpu.h off trace/control.h and
trace/control-internal.h.  Have the generated trace.h include
trace/control.h (which no longer includes qom/cpu.h), and trace-root.h
include trace/control-vcpu.h (which includes it).

The resulting improvement is a bit disappointing: in my "build
everything" tree, some 1100 out of 6600 objects (not counting tests
and objects that don't depend on qemu/osdep.h) depend on a trace.h,
and about 600 of them no longer depend on qom/cpu.h.  But more than
1300 others depend on trace-root.h.  More work is clearly needed.
Left for another day.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190812052359.30071-8-armbru@redhat.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/trace/control-vcpu.h b/trace/control-vcpu.h
new file mode 100644
index 0000000000..a8f1035c2e
--- /dev/null
+++ b/trace/control-vcpu.h
@@ -0,0 +1,63 @@
+/*
+ * Interface for configuring and controlling the state of tracing events.
+ *
+ * Copyright (C) 2011-2016 Lluís Vilanova <vilanova@ac.upc.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef TRACE__CONTROL_VCPU_H
+#define TRACE__CONTROL_VCPU_H
+
+#include "control.h"
+#include "event-internal.h"
+#include "qom/cpu.h"
+
+/**
+ * trace_event_get_vcpu_state:
+ * @vcpu: Target vCPU.
+ * @id: Event identifier name.
+ *
+ * Get the tracing state of an event (both static and dynamic) for the given
+ * vCPU.
+ *
+ * If the event has the disabled property, the check will have no performance
+ * impact.
+ */
+#define trace_event_get_vcpu_state(vcpu, id)                            \
+    ((id ##_ENABLED) &&                                                 \
+     trace_event_get_vcpu_state_dynamic_by_vcpu_id(                     \
+         vcpu, _ ## id ## _EVENT.vcpu_id))
+
+/**
+ * trace_event_get_vcpu_state_dynamic:
+ *
+ * Get the dynamic tracing state of an event for the given vCPU.
+ */
+static bool trace_event_get_vcpu_state_dynamic(CPUState *vcpu, TraceEvent *ev);
+
+#include "control-internal.h"
+
+static inline bool
+trace_event_get_vcpu_state_dynamic_by_vcpu_id(CPUState *vcpu,
+                                              uint32_t vcpu_id)
+{
+    /* it's on fast path, avoid consistency checks (asserts) */
+    if (unlikely(trace_events_enabled_count)) {
+        return test_bit(vcpu_id, vcpu->trace_dstate);
+    } else {
+        return false;
+    }
+}
+
+static inline bool trace_event_get_vcpu_state_dynamic(CPUState *vcpu,
+                                                      TraceEvent *ev)
+{
+    uint32_t vcpu_id;
+    assert(trace_event_is_vcpu(ev));
+    vcpu_id = trace_event_get_vcpu_id(ev);
+    return trace_event_get_vcpu_state_dynamic_by_vcpu_id(vcpu, vcpu_id);
+}
+
+#endif