Fix qapi code generation wrt parallel build
Make's multiple output syntax
x.c x.h: x.template
gen < x.template
actually invokes the command once for x.c and once for x.h (with differing $@
in each invocation). During a parallel build, the two commands may be invoked
in parallel; this opens up a race, where the second invocation trashes a file
supposedly produced during the first, and now in use by a dependent command.
The various qapi code generators are susceptible to this; fix by making them
generate just one file per invocation.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index 54d1f5d..bd7b207 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -372,7 +372,9 @@
try:
- opts, args = getopt.gnu_getopt(sys.argv[1:], "p:o:m", ["prefix=", "output-dir=", "type=", "middle"])
+ opts, args = getopt.gnu_getopt(sys.argv[1:], "chp:o:m",
+ ["source", "header", "prefix=",
+ "output-dir=", "type=", "middle"])
except getopt.GetoptError, err:
print str(err)
sys.exit(1)
@@ -384,6 +386,9 @@
h_file = 'qmp-commands.h'
middle_mode = False
+do_c = False
+do_h = False
+
for o, a in opts:
if o in ("-p", "--prefix"):
prefix = a
@@ -393,10 +398,29 @@
dispatch_type = a
elif o in ("-m", "--middle"):
middle_mode = True
+ elif o in ("-c", "--source"):
+ do_h = True
+ elif o in ("-h", "--header"):
+ do_c = True
+
+if not do_c and not do_h:
+ do_c = True
+ do_h = True
c_file = output_dir + prefix + c_file
h_file = output_dir + prefix + h_file
+def maybe_open(really, name, opt):
+ class Null(object):
+ def write(self, str):
+ pass
+ def read(self):
+ return ''
+ if really:
+ return open(name, opt)
+ else:
+ return Null()
+
try:
os.makedirs(output_dir)
except os.error, e:
@@ -408,8 +432,8 @@
commands = filter(lambda expr: not expr.has_key('gen'), commands)
if dispatch_type == "sync":
- fdecl = open(h_file, 'w')
- fdef = open(c_file, 'w')
+ fdecl = maybe_open(do_h, h_file, 'w')
+ fdef = maybe_open(do_c, c_file, 'w')
ret = gen_command_decl_prologue(header=basename(h_file), guard=guardname(h_file), prefix=prefix)
fdecl.write(ret)
ret = gen_command_def_prologue(prefix=prefix)