[Qemu-devel] [PATCH][RFC] New trace-event backend: stdio

[Fabien Chouteau]

This backend sends trace events to standard output during the emulation.

Signed-off-by: Fabien Chouteau <address@hidden>
---
 configure         |    2 +-
 docs/tracing.txt  |    5 +++++
 scripts/tracetool |   52 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index 210670c..2672f2a 100755
--- a/configure
+++ b/configure
@@ -907,7 +907,7 @@ echo "  --enable-docs            enable documentation build"
 echo "  --disable-docs           disable documentation build"
 echo "  --disable-vhost-net      disable vhost-net acceleration support"
 echo "  --enable-vhost-net       enable vhost-net acceleration support"
-echo "  --enable-trace-backend=B Trace backend nop simple ust dtrace"
+echo "  --enable-trace-backend=B Trace backend nop simple stdio ust dtrace"
 echo "  --with-trace-file=NAME   Full PATH,NAME of file to store traces"
 echo "                           Default:trace-<pid>"
 echo "  --disable-spice          disable spice"
diff --git a/docs/tracing.txt b/docs/tracing.txt
index 963c504..de033ad 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -133,6 +133,11 @@ source tree.  It may not be as powerful as 
platform-specific or third-party
 trace backends but it is portable.  This is the recommended trace backend
 unless you have specific needs for more advanced backends.
 
+=== Stdio ===
+
+The "stdio" backend sends trace events directly to standard output during
+emulation.
+
 ==== Monitor commands ====
 
 * info trace
diff --git a/scripts/tracetool b/scripts/tracetool
index fce491c..01f81a1 100755
--- a/scripts/tracetool
+++ b/scripts/tracetool
@@ -19,6 +19,7 @@ Generate tracing code for a file on stdin.
 Backends:
   --nop     Tracing disabled
   --simple  Simple built-in backend
+  --stdio   Stdio built-in backend
   --ust     LTTng User Space Tracing backend
   --dtrace  DTrace/SystemTAP backend
 
@@ -236,6 +237,55 @@ linetoc_end_simple()
 EOF
 }
 
+#STDIO
+linetoh_begin_stdio()
+{
+    return
+}
+
+linetoh_stdio()
+{
+    local name args argnamess argc fmt
+    name=$(get_name "$1")
+    args=$(get_args "$1")
+    argnames=$(get_argnames "$1" ",")
+    argc=$(get_argc "$1")
+    state=$(get_state "$1")
+    fmt=$(get_fmt "$1")
+
+    if [ "$argc" -gt 0 ]; then
+        argnames=", $argnames"
+    fi
+
+    cat <<EOF
+static inline void trace_$name($args)
+{
+    printf("$name $fmt\n" $argnames);
+}
+EOF
+}
+
+linetoh_end_stdio()
+{
+return
+}
+
+linetoc_begin_stdio()
+{
+return
+}
+
+linetoc_stdio()
+{
+return
+}
+
+linetoc_end_stdio()
+{
+return
+}
+#END OF STDIO
+
 # Clean up after UST headers which pollute the namespace
 ust_clean_namespace() {
     cat <<EOF
@@ -546,7 +596,7 @@ targetarch=
 until [ -z "$1" ]
 do
   case "$1" in
-    "--nop" | "--simple" | "--ust" | "--dtrace") backend="${1#--}" ;;
+    "--nop" | "--simple" | "--stdio" | "--ust" | "--dtrace") backend="${1#--}" 
;;
 
     "--binary") shift ; binary="$1" ;;
     "--target-arch") shift ; targetarch="$1" ;;
-- 
1.7.1