Build: wrap make invocations with flock(1)

Lock each directory before entering it so when using -j, the same
dependency isn't built more than once at a time.

This doesn't get full -j parallelism though, since one make child
will be sitting idle waiting for flock to receive its lock and
continue making (which should then do nothing since it will have
been built already).  Unfortunately there's not much that can be
done to fix that since it can't proceed until its dependency is
built by another make process.

AK/Tests/Makefile

@@ -35,7 +35,6 @@ SHARED_TEST_OBJS = \
 
 define execute-command
 $(1)
-
 endef
 
 all: $(PROGRAMS)

Applications/Browser/Makefile

@@ -7,10 +7,10 @@ LIB_DEPS = GUI HTML Draw IPC Protocol Core
 
 main.cpp: ../../Libraries/LibHTML/CSS/PropertyID.h
 ../../Libraries/LibHTML/CSS/PropertyID.h:
-	@$(MAKE) -C ../../Libraries/LibHTML
+	@flock ../../Libraries/LibHTML $(MAKE) -C ../../Libraries/LibHTML
 
 main.cpp: ../../Servers/ProtocolServer/ProtocolClientEndpoint.h
 ../../Servers/ProtocolServer/ProtocolClientEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock ../../Servers/ProtocolServer $(MAKE) -C $(dir $(@))
 
 include ../../Makefile.common

Libraries/LibAudio/Makefile

@@ -6,7 +6,7 @@ LIBRARY = libaudio.a
 
 AClientConnection.cpp: ../../Servers/AudioServer/AudioClientEndpoint.h
 ../../Servers/AudioServer/AudioClientEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibAudio/

Libraries/LibC/Makefile

@@ -1,5 +1,3 @@
-.NOTPARALLEL:
-
 AK_OBJS = \
     ../../AK/StringImpl.o \
     ../../AK/String.o \
@@ -62,7 +60,6 @@ OBJS = $(AK_OBJS) $(LIBC_OBJS)
 EXTRA_OBJS = setjmp.ao crti.ao crtn.ao
 
 crt0.o: crt0.cpp
-	$(QUIET) $(CXX) $(CXXFLAGS) -o crt0.o -c crt0.cpp
 
 crtio.o: crti.ao
 	$(QUIET) cp crti.ao crti.o
@@ -76,7 +73,9 @@ DEFINES = -DSERENITY_LIBC_BUILD
 
 LIBRARY = libc.a
 
-all: crt0.o $(EXTRA_OBJS) $(LIBRARY) install
+POST_LIBRARY_BUILD = $(QUIET) $(MAKE) install
+
+all: crt0.o $(EXTRA_OBJS) $(LIBRARY)
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/sys/

Libraries/LibGUI/Makefile

@@ -66,7 +66,7 @@ LIBRARY = libgui.a
 GWindowServerConnection.cpp: ../../Servers/WindowServer/WindowServerEndpoint.h
 
 ../../Servers/WindowServer/WindowServerEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 install:
 	mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibGUI/

Libraries/LibHTML/Makefile

@@ -71,10 +71,10 @@ GENERATE_CSS_PROPERTYID_CPP = CodeGenerators/Generate_CSS_PropertyID_cpp/Generat
 GENERATE_CSS_PROPERTYID_H = CodeGenerators/Generate_CSS_PropertyID_h/Generate_CSS_PropertyID_h
 
 $(GENERATE_CSS_PROPERTYID_H):
-	@$(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_H))
+	@flock $(dir $(GENERATE_CSS_PROPERTYID_H)) $(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_H))
 
 $(GENERATE_CSS_PROPERTYID_CPP):
-	@$(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_CPP))
+	@flock $(dir $(GENERATE_CSS_PROPERTYID_CPP)) $(MAKE) -C $(dir $(GENERATE_CSS_PROPERTYID_CPP))
 
 CSS/DefaultStyleSheetSource.cpp: CSS/Default.css Scripts/GenerateStyleSheetSource.sh
 	@echo "GENERATE $@"
@@ -82,11 +82,11 @@ CSS/DefaultStyleSheetSource.cpp: CSS/Default.css Scripts/GenerateStyleSheetSourc
 
 CSS/PropertyID.h: CSS/Properties.json $(GENERATE_CSS_PROPERTYID_H)
 	@echo "GENERATE $@"
-	$(QUIET) $(GENERATE_CSS_PROPERTYID_H) $< > $@
+	$(QUIET) flock CSS $(GENERATE_CSS_PROPERTYID_H) $< > $@
 
 CSS/PropertyID.cpp: CSS/Properties.json $(GENERATE_CSS_PROPERTYID_CPP)
 	@echo "GENERATE $@"
-	$(QUIET) $(GENERATE_CSS_PROPERTYID_CPP) $< > $@
+	$(QUIET) flock CSS $(GENERATE_CSS_PROPERTYID_CPP) $< > $@
 
 EXTRA_CLEAN = CSS/DefaultStyleSheetSource.cpp CSS/PropertyID.h CSS/PropertyID.cpp
 

Libraries/LibProtocol/Makefile

@@ -6,6 +6,6 @@ LIBRARY = libprotocol.a
 
 Download.cpp: ../../Servers/ProtocolServer/ProtocolClientEndpoint.h
 ../../Servers/ProtocolServer/ProtocolClientEndpoint.h:
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 include ../../Makefile.common

Makefile

@@ -23,6 +23,6 @@ ifeq ($(UNAME_S),Darwin)
 test: 
 else
 test:
-	$(QUIET) $(MAKE) -C AK/Tests clean all clean
+	$(QUIET) flock AK/Tests $(MAKE) -C AK/Tests clean all clean
 endif
 

Makefile.common

@@ -103,19 +103,21 @@ $(PROGRAM): $(STATIC_LIB_DEPS) $(SUFFIXED_OBJS) $(EXTRA_OBJS)
 $(LIBRARY): $(SUFFIXED_OBJS) $(EXTRA_OBJS)
 	@echo "LIB $@"
 	$(QUIET) $(AR) rcs $@ $(OBJS) $(EXTRA_OBJS) $(LIBS)
+	$(POST_LIBRARY_BUILD)
 
+#.PHONY: $(STATIC_LIB_DEPS)
 $(STATIC_LIB_DEPS):
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 IPCCOMPILER = $(SERENITY_BASE_DIR)/DevTools/IPCCompiler/IPCCompiler
 IPCCOMPILER: $(IPCCOMPILER)
 $(IPCCOMPILER):
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 FORMCOMPILER = $(SERENITY_BASE_DIR)/DevTools/FormCompiler/FormCompiler
 FORMCOMPILER: $(FORMCOMPILER)
 $(FORMCOMPILER):
-	@$(MAKE) -C $(dir $(@))
+	@flock $(dir $(@)) $(MAKE) -C $(dir $(@))
 
 .DEFAULT_GOAL := all
 

Makefile.subdir

@@ -1,17 +1,17 @@
 subdirs: $(SUBDIRS)
 $(SUBDIRS):
-	@$(MAKE) -C $@
+	@flock $@ $(MAKE) -C $@
 
 all: $(subdirs)
 
 SUBDIRS_CLEAN = $(addsuffix .clean,$(SUBDIRS))
 clean: $(SUBDIRS_CLEAN)
 $(SUBDIRS_CLEAN): %.clean:
-	@$(MAKE) -C $* clean
+	@flock $* $(MAKE) -C $* clean
 
 SUBDIRS_INSTALL = $(addsuffix .install,$(SUBDIRS))
 install: $(SUBDIRS_INSTALL)
 $(SUBDIRS_INSTALL): %.install:
-	@$(MAKE) -C $* install
+	@flock $* $(MAKE) -C $* install
 
 .PHONY: all clean install $(SUBDIRS)