[Qemu-devel] [Tracing][PATCH] Compilation fixes

[Prerna Saxena]

Fix to ensure rebuild is properly triggered when switching trace backends 
using ./configure.
Also, when using the 'ust' backend, check if the relevant headers are 
available at host.

Signed-off-by: Prerna Saxena <address@hidden>
---
 Makefile  |    4 ++--
 configure |   20 +++++++++++++++++---
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 8831174..3bd41ce 100644
--- a/Makefile
+++ b/Makefile
@@ -132,10 +132,10 @@ bt-host.o: QEMU_CFLAGS += $(BLUEZ_CFLAGS)
 
 iov.o: iov.c iov.h
 
-trace.h: $(SRC_PATH)/trace-events
+trace.h: $(SRC_PATH)/trace-events config-host.mak
        $(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -h < 
$< > $@,"  GEN   $@")
 
-trace.c: $(SRC_PATH)/trace-events
+trace.c: $(SRC_PATH)/trace-events config-host.mak
        $(call quiet-command,sh $(SRC_PATH)/tracetool --$(TRACE_BACKEND) -c < 
$< > $@,"  GEN   $@")
 
 trace.o: trace.c $(GENERATED_HEADERS)
diff --git a/configure b/configure
index fe1b027..ee9f1e3 100755
--- a/configure
+++ b/configure
@@ -2011,6 +2011,23 @@ if test "$?" -ne 0 ; then
   exit 1
 fi
 
+##########################################
+# For 'ust' backend, test if ust headers are present
+if test "$trace_backend" = "ust"; then
+  cat > $TMPC << EOF
+#include <ust/tracepoint.h>
+#include <ust/marker.h>
+int main(void) { return 0; }
+EOF
+  if compile_prog "" "" ; then
+    LIBS="-lust $LIBS"
+  else
+    echo "ERROR: Trace backend 'ust' does not have relevant headers available"
+    echo "       on the host. Pls choose a different backend."
+    exit 1
+  fi
+fi
+##########################################
 # End of CC checks
 # After here, no more $cc or $ld runs
 
@@ -2392,9 +2409,6 @@ echo "TRACE_BACKEND=$trace_backend" >> $config_host_mak
 if test "$trace_backend" = "simple"; then
   echo "CONFIG_SIMPLE_TRACE=y" >> $config_host_mak
 fi
-if test "$trace_backend" = "ust"; then
-  LIBS="-lust $LIBS"
-fi
 # Set the appropriate trace file.
 if test "$trace_backend" = "simple"; then
   trace_file="\"$trace_file-%u\""
-- 
1.6.2.5



-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India