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Fix qapi code generation wrt parallel build
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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 <[email protected]>
Signed-off-by: Anthony Liguori <[email protected]>
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@avikivity
avikivity authored and Anthony Liguori committed Dec 27, 2011
1 parent 4e1ea51 commit 8d3bc51
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Showing 4 changed files with 86 additions and 18 deletions.
20 changes: 11 additions & 9 deletions Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -173,35 +173,37 @@ qapi-dir := $(BUILD_DIR)/qapi-generated
test-qmp-input-visitor.o test-qmp-output-visitor.o test-qmp-commands.o qemu-ga$(EXESUF): QEMU_CFLAGS += -I $(qapi-dir)
qemu-ga$(EXESUF): LIBS = $(LIBS_QGA)

gen-out-type = $(subst .,-,$@)

$(qapi-dir)/test-qapi-types.c $(qapi-dir)/test-qapi-types.h :\
$(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-types.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py -o "$(qapi-dir)" -p "test-" < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py $(gen-out-type) -o "$(qapi-dir)" -p "test-" < $<, " GEN $@")
$(qapi-dir)/test-qapi-visit.c $(qapi-dir)/test-qapi-visit.h :\
$(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-visit.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-visit.py -o "$(qapi-dir)" -p "test-" < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-visit.py $(gen-out-type) -o "$(qapi-dir)" -p "test-" < $<, " GEN $@")
$(qapi-dir)/test-qmp-commands.h $(qapi-dir)/test-qmp-marshal.c :\
$(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-commands.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py -o "$(qapi-dir)" -p "test-" < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py $(gen-out-type) -o "$(qapi-dir)" -p "test-" < $<, " GEN $@")

$(qapi-dir)/qga-qapi-types.c $(qapi-dir)/qga-qapi-types.h :\
$(SRC_PATH)/qapi-schema-guest.json $(SRC_PATH)/scripts/qapi-types.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py -o "$(qapi-dir)" -p "qga-" < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py $(gen-out-type) -o "$(qapi-dir)" -p "qga-" < $<, " GEN $@")
$(qapi-dir)/qga-qapi-visit.c $(qapi-dir)/qga-qapi-visit.h :\
$(SRC_PATH)/qapi-schema-guest.json $(SRC_PATH)/scripts/qapi-visit.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-visit.py -o "$(qapi-dir)" -p "qga-" < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-visit.py $(gen-out-type) -o "$(qapi-dir)" -p "qga-" < $<, " GEN $@")
$(qapi-dir)/qga-qmp-commands.h $(qapi-dir)/qga-qmp-marshal.c :\
$(SRC_PATH)/qapi-schema-guest.json $(SRC_PATH)/scripts/qapi-commands.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py -o "$(qapi-dir)" -p "qga-" < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py $(gen-out-type) -o "$(qapi-dir)" -p "qga-" < $<, " GEN $@")

qapi-types.c qapi-types.h :\
$(SRC_PATH)/qapi-schema.json $(SRC_PATH)/scripts/qapi-types.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py -o "." < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py $(gen-out-type) -o "." < $<, " GEN $@")
qapi-visit.c qapi-visit.h :\
$(SRC_PATH)/qapi-schema.json $(SRC_PATH)/scripts/qapi-visit.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-visit.py -o "." < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-visit.py $(gen-out-type) -o "." < $<, " GEN $@")
qmp-commands.h qmp-marshal.c :\
$(SRC_PATH)/qapi-schema.json $(SRC_PATH)/scripts/qapi-commands.py
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py -m -o "." < $<, " GEN $@")
$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py $(gen-out-type) -m -o "." < $<, " GEN $@")

test-qmp-output-visitor.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
test-qmp-output-visitor: test-qmp-output-visitor.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o
Expand Down
30 changes: 27 additions & 3 deletions scripts/qapi-commands.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -372,7 +372,9 @@ def gen_command_def_prologue(prefix="", proxy=False):


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)
Expand All @@ -384,6 +386,9 @@ def gen_command_def_prologue(prefix="", proxy=False):
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
Expand All @@ -393,10 +398,29 @@ def gen_command_def_prologue(prefix="", proxy=False):
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:
Expand All @@ -408,8 +432,8 @@ def gen_command_def_prologue(prefix="", proxy=False):
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)
Expand Down
27 changes: 24 additions & 3 deletions scripts/qapi-types.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -163,7 +163,8 @@ def generate_type_cleanup(name):


try:
opts, args = getopt.gnu_getopt(sys.argv[1:], "p:o:", ["prefix=", "output-dir="])
opts, args = getopt.gnu_getopt(sys.argv[1:], "chp:o:",
["source", "header", "prefix=", "output-dir="])
except getopt.GetoptError, err:
print str(err)
sys.exit(1)
Expand All @@ -173,11 +174,22 @@ def generate_type_cleanup(name):
c_file = 'qapi-types.c'
h_file = 'qapi-types.h'

do_c = False
do_h = False

for o, a in opts:
if o in ("-p", "--prefix"):
prefix = a
elif o in ("-o", "--output-dir"):
output_dir = a + "/"
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
Expand All @@ -188,8 +200,17 @@ def generate_type_cleanup(name):
if e.errno != errno.EEXIST:
raise

fdef = open(c_file, 'w')
fdecl = open(h_file, 'w')
def maybe_open(really, name, opt):
class Null(object):
def write(self, str):
pass
def read(self):
return ''
if really:
return open(name, opt)

fdef = maybe_open(do_c, c_file, 'w')
fdecl = maybe_open(do_h, h_file, 'w')

fdef.write(mcgen('''
/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
Expand Down
27 changes: 24 additions & 3 deletions scripts/qapi-visit.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -139,7 +139,8 @@ def generate_decl_enum(name, members, genlist=True):
name=name)

try:
opts, args = getopt.gnu_getopt(sys.argv[1:], "p:o:", ["prefix=", "output-dir="])
opts, args = getopt.gnu_getopt(sys.argv[1:], "chp:o:",
["source", "header", "prefix=", "output-dir="])
except getopt.GetoptError, err:
print str(err)
sys.exit(1)
Expand All @@ -149,11 +150,22 @@ def generate_decl_enum(name, members, genlist=True):
c_file = 'qapi-visit.c'
h_file = 'qapi-visit.h'

do_c = False
do_h = False

for o, a in opts:
if o in ("-p", "--prefix"):
prefix = a
elif o in ("-o", "--output-dir"):
output_dir = a + "/"
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
Expand All @@ -164,8 +176,17 @@ def generate_decl_enum(name, members, genlist=True):
if e.errno != errno.EEXIST:
raise

fdef = open(c_file, 'w')
fdecl = open(h_file, 'w')
def maybe_open(really, name, opt):
class Null(object):
def write(self, str):
pass
def read(self):
return ''
if really:
return open(name, opt)

fdef = maybe_open(do_c, c_file, 'w')
fdecl = maybe_open(do_h, h_file, 'w')

fdef.write(mcgen('''
/* THIS FILE IS AUTOMATICALLY GENERATED, DO NOT MODIFY */
Expand Down

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