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The Makefile utility

The Makefile utility. Motivation. Small programs single file “Not so small” programs : Many lines of code Multiple components More than one programmer. Motivation – continued. Problems: Long files are harder to manage (for both programmers and machines)

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The Makefile utility

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  1. The Makefile utility

  2. Motivation • Small programs single file • “Not so small” programs : • Many lines of code • Multiple components • More than one programmer

  3. Motivation – continued • Problems: • Long files are harder to manage (for both programmers and machines) • Every change requires long compilation • Many programmers can not modify the same file simultaneously • Division to components is desired

  4. Motivation – continued • Solution : divide project to multiple files • Targets: • Good division to components • Minimum compilation when something is changed • Easy maintenance of project structure, dependencies and creation

  5. Project maintenance • Done in Unix by the Makefile mechanism • A makefile is a file (script) containing : • Project structure (files, dependencies) • Instructions for files creation • The make command reads a makefile, understands the project structure and makes up the executable • Note that the Makefile mechanism is not limited to C programs

  6. Project structure • Project structure and dependencies can be represented as a DAG (= Directed Acyclic Graph) • Example : • Program contains 3 files • main.c., sum.c, sum.h • sum.h included in both .c files • Executable should be the file sum

  7. sum (exe) sum.o main.o main.c sum.h sum.c sum.h

  8. Make: Header Dependencies • What if … • Sensor.cc changes? • Sensor.h changes? • Robot.h changes? • Pattern rule ignores header dependencies! • Requires unnecessary “make clean; make” • Let gcc figure out the header dependencies for us! • The –MM option produces make rules in a .d file which we can then include in the Makefile Sensor.h Sensor.cc Robot.h Robot.cc robotest.cc

  9. makefile sum: main.o sum.o gcc –o sum main.o sum.o main.o: main.c sum.h gcc –c main.c sum.o: sum.c sum.h gcc –c sum.c

  10. Rule syntax main.o: main.c sum.h gcc –c main.c tab dependency action Rule

  11. Equivalent makefiles • .o depends (by default) on corresponding .c file. Therefore, equivalent makefile is: sum: main.o sum.o gcc –o sum main.o sum.o main.o: sum.h gcc –c main.c sum.o: sum.h gcc –c sum.c

  12. Equivalent makefiles - continued • We can compress identical dependencies and use built-in macros to get another (shorter) equivalent makefile : sum: main.o sum.o gcc –o $@ main.o sum.o main.o sum.o: sum.h gcc –c $*.c

  13. make operation • Project dependencies tree is constructed • Target of first rule should be created • We go down the tree to see if there is a target that should be recreated. This is the case when the target file is older than one of its dependencies • In this case we recreate the target file according to the action specified, on our way up the tree. Consequently, more files may need to be recreated • If something is changed, linking is usually necessary

  14. make operation - continued • make operation ensures minimum compilation, when the project structure is written properly • Do not write something like: prog: main.c sum1.c sum2.c gcc –o prog main.c sum1.c sum2.c which requires compilation of all project when something is changed

  15. Make operation - example FileLast Modified sum 10:03 main.o 09:56 sum.o 09:35 main.c 10:45 sum.c 09:14 sum.h 08:39

  16. Make operation - example • Operations performed: gcc –c main.c gcc –o sum main.o sum.o • main.o should be recompiled (main.c is newer). • Consequently, main.o is newer than sum and therefore sum should be recreated (by re-linking).

  17. Another makefile example # Makefile to compare sorting routines BASE = /home/blufox/base CC = gcc CFLAGS = -O –Wall EFILE = $(BASE)/bin/compare_sorts INCLS = -I$(LOC)/include LIBS = $(LOC)/lib/g_lib.a \ $(LOC)/lib/h_lib.a LOC = /usr/local OBJS = main.o another_qsort.o chk_order.o \ compare.o quicksort.o $(EFILE): $(OBJS) @echo “linking …” @$(CC) $(CFLAGS) –o $@ $(OBJS) $(LIBS) $(OBJS): compare_sorts.h $(CC) $(CFLAGS) $(INCLS) –c $*.c # Clean intermediate files clean: rm *~ $(OBJS)

  18. Example - continued • We can define multiple targets in a makefile • Target clean – has an empty set of dependencies. Used to clean intermediate files. • make • Will create the compare_sorts executable • make clean • Will remove intermediate files

  19. Passing parameters to makefile • We can pass parameters to a makefile by specifying them along with their values in the command line. • For example: make PAR1=1 PAR2=soft1 will call the makefile with 2 parameters: PAR1 is assigned the value “1” and PAR2 is assigned the value “soft1”. The same names should be used within the makefile to access these variables (using the usual “$(VAR_NAME)” syntax)

  20. Passing parameters - continued • Note that assigning a value to a variable within the makefileoverrides any value passed from the command line. • For example: command line : make PAR=1 in the makefile: PAR = 2 • PAR value within the makefile will be 2, overriding the value sent from the command line

  21. Conditional statements • Simple conditional statements can be included in a makefile. • Usual syntax is: ifeq (value1, value2) body of if else body of else endif

  22. Conditional statements - example sum: main.o sum.o gcc –o sum main.o sum.o main.o: main.c sum.h gcc –c main.c #deciding which file to compile to create sum.o ifeq ($(USE_SUM), 1) sum.o: sum1.c sum.h gcc –c sum1.c –o $@ else sum.o: sum2.c sum.h gcc –c sum2.c –o $@ endif

  23. Make: Advanced Options • Text manipulation functions • $(patsubst pattern,replacement,text) • $(patsubst %.o,%.cc,<list of objfiles>) • Pattern rules • Uses a pattern in the target with % as wildcard • Matched % can be used in dependencies as well • Simple Example: %.o : %.cc <tab>command … • Pattern rules with automatic variables • $@ full target name • $< first dependency • $* string which matched % wildcard • Advance Example: %.o : %.cc <tab>$(CC) $(CCFLAGS) –c $< $(INCPATHS)

  24. Make: A Simple Example CC=g++ # Compiler to use FLAGS=-g # Compile flags MASLAB_ROOT=maslab-software # Maslab software root directory LIB_DIR=$(MASLAB_ROOT)/liborc # orc-related library directory INC_DIR=$(MASLAB_ROOT)/liborc # orc-related include directory LIBS=-lm –lpthread -lorc # Library files all : helloworld helloworld.o : helloworld.cc $(CC) $(FLAGS) –c $*.cc –o $@ helloworld: helloworld.o $(CC) -o helloworld helloworld.o $(LIBS) clean: rm -f *.o helloworld

  25. Make: Example Makefile MASLABROOT = /mnt/maslab/software/maslab-software-current #This is the list of places to look for include files INCPATHS = -I$(MASLABROOT)/libs/liborc \ -I$(MASLABROOT)/libs/libim \ -I$(MASLABROOT)/libs/libbotserver \ -I/opt/intel/ipp/include #This is the list of places to look for libraries LIBPATHS = -L$(MASLABROOT)/libs/liborc \ -L$(MASLABROOT)/libs/libim \ -L$(MASLABROOT)/libs/libbotserver \ -L/opt/intel/ipp/sharedlib #This is the names of the libraries LIBS = -lippipx -lippcvpx -lim -lorc -lbotserver -lm -lpthread -ljpeg -lpng #This is the compiler to use CC = g++ # This is your c++ file extension (usually cc or cpp) CCEXT = cc

  26. Make: Example Makefile (cont) CCFLAGS = -g -Wall # This rule builds everything. You should put the names of all your # programs in this list. all : robotest # This rule says how to turn any .cpp file into a .o file. %.o : %.$(CCEXT) $(CC) $(CCFLAGS) -c $< $(INCPATHS) #---------------------------------------------------------------------- # robotest PROGRAM_NAME = robotest PROGRAM_OBJS = robotest.o BumpSensor.o Robot.o GLOBAL_OBJS += $(PROGRAM_OBJS) JUNK += $(PROGRAM_NAME) $(PROGRAM_NAME): $(PROGRAM_OBJS) $(CC) $(PROGRAM_OBJS) -o $(PROGRAM_NAME) $(LIBS) $(LIBPATHS) chmod a+x $(PROGRAM_NAME)

  27. Extending Example Makefile So to add a new executable program, simply cut and paste the robotest section and enter your own PROGRAM_NAME and PROGRAM_OBJS #---------------------------------------------------------------------- # Sensor Incremental Test PROGRAM_NAME = sensor-test PROGRAM_OBJS = sensor.t.o BumpSensor.o GLOBAL_OBJS += $(PROGRAM_OBJS) JUNK += $(PROGRAM_NAME) $(PROGRAM_NAME): $(PROGRAM_OBJS) $(CC) $(PROGRAM_OBJS) -o $(PROGRAM_NAME) $(LIBS) $(LIBPATHS) chmod a+x $(PROGRAM_NAME)

  28. Extending example Makefile DEPENDS += $(patsubst %.o, %.d, $(GLOBAL_OBJS)) JUNK += $(DEPENDS) include $(DEPENDS) depend : $(DEPENDS) depend.$(CCEXT) = set -e; $(CC) $(CCFLAGS) -MM $(DEFS) $(INCPATHS) depend.filt = sed 's/\($*\)\.o[ :]*/\1.o $@ : /g' > $@; [ -s $@ ] || rm -f $@ %.d: %.$(CCEXT) $(depend.cc) $< | $(depend.filt) #====================================================================== # Miscellaneous Rules #---------------------------------------------------------------------- # This rule cleans your directory. You could also add commands here # to remove program files and any other files that should be cleaned clean: rm -f $(JUNK) *~ *.o core.[0-9]* core

  29. ANT:Another Nice Tool

  30. What is Ant? • Java-based Build tool from Apache • De facto standard for building, packaging, and installing Java applications • Accomplishes same objectives that make does on Unix based systems • Files are written in XML

  31. Why Ant? • Many claim.. That • Unlike makefiles, Ant files work cross platform - No need for multiple, complex makefiles depending on the operating system. - Tasks declared in platform independent way; Ant engine translates to OS specific commands. But still need to know (potentially) complex path/install data. So not as general as they claim • Easy to create own Ant “tasks”, in addition to core tasks

  32. Installing Ant • Download Ant binary distribution from: http://ant.apache.org/bindownload.cgi • Set ANT_HOME to where you installed Ant • Include $ANT_HOME/bin in PATH • Make sure JAVA_HOME is set to point to JDK

  33. Running Ant • Type “ant” at the command line • Automatically looks for build.xml file in current directory to run • Type “ant –buildfile buildfile.xml” to specify another build file to run.

  34. Ant Output

  35. Sample build.xml <project name="MyProject" default="dist" basedir="."> <property name="src" location="src"/> <property name="build" location="build"/> <property name="dist" location="dist"/> <target name="init"> <tstamp/> <mkdir dir="${build}"/> </target> <target name="compile" depends="init" > <javac srcdir="${src}" destdir="${build}"/> </target> <target name="dist" depends="compile" > <mkdir dir="${dist}/lib"/> <jar jarfile="${dist}/lib/MyProject-${DSTAMP}.jar" basedir="${build}"/> </target> <target name="clean" > <delete dir="${build}"/> <delete dir="${dist}"/> </target> </project>

  36. Ant Overview: Project • Each build file contains exactly one project and at least one target • Project tags specify the basic project attributes and have 3 properties: - name - default target - basedir • Example: <project name=“MyProject” default=“build” basedir=“.”>

  37. Ant Overview: Targets • Target is a build module in Ant • Each target contains task(s) for Ant to do • One must be a project default • Overall structure of targets: <target name="A"/> <target name="B" depends="A"/> <target name="C" depends="B"/> <target name="D" depends="C,B,A"/>

  38. Ant Overview: Tasks • Each target comprises one or more tasks • Task is a piece of executable Java code (e.g. javac, jar, etc) • Tasks do the actual “build” work in Ant • Ant has core (built in) tasks and the ability to create own tasks

  39. Ant Overview: Tasks Example: <target name="prepare" depends="init“ > <mkdir dir="${build}" /> </target> <target name="build" depends="copy" > <javac srcdir="src" destdir="${build}"> <include name="**/*.java" /> </javac> </target>

  40. Ant Overview: Core Tasks • javac – Runs the Java Compiler • java – Runs the Java Virtual Machine • jar (and war) – Create JAR files • mkdir – Makes a directory • copy – Copies files to specified location • delete – Deletes specified files • cvs – Invokes CVS commands from Ant

  41. Ant Overview: Writing Own Task • Create a Java class that extends org.apache.tools.ant.Task • For each attribute, write a setter method that is public voidand takes a single argument • Write a public void execute() method, with no arguments, that throws a BuildException -- this method implements the task itself

  42. Ant Overview: Properties • Special task for setting up build file properties: • Example: <property name=“src” value=“/home/src”/> • Can use ${src} anywhere in build file to denote /home/src • Ant provides access to all system properties as if defined by the <property> task

  43. Ant Overview: Path Structures • Ant provides means to set various environment variables like PATH and CLASSPATH. • Example of setting CLASSPATH: <classpath> <pathelement path="${classpath}"/> <pathelement location="lib/helper.jar"/> </classpath>

  44. Command Line Arguments • -buildfile buildfile– specify build file to use • targetname – specify target to run (instead of running default) • -verbose, -quiet, -debug – Allows control over the logging information Ant outputs • -logger classname– Allows user to specify their own classes for logging Ant events

  45. IDE Integration • Eclipse, NetBeans, JBuilder, VisualAge, and almost any other Java IDE has Ant integration built-in to the system • Refer to each IDE’s documentation for how to use Ant with that IDE

  46. Web Development with Ant • Tomcat comes with special Ant tasks to ease Web application development and deployment • Copy $TOMCAT_HOME/server/lib/catalina-ant.jar to $ANT_HOME/lib • Ant tasks for Tomcat: - install - reload - deploy - remove

  47. Documentation/References • Good tutorial for makefiles http://www.gnu.org/manual/make-3.80/make.html • Good tutorial for cmakef http://www.cmake.org/HTML/Documentation.html • ANT User Manual: http://ant.apache.org/manual/index.html • Sun’s Web development tutorial (Ant and JSPs): http://java.sun.com/webservices/docs/1.2/tutorial/doc/GettingStarted3.html

  48. The real Problem • How do we handle platform specific issues? • Providing a different Makefile for each architecture • Using Autoconf, Automake and Libtool • The installer needs only • Bourne shell • C compilers • Make program

  49. Some advantages when using GNU autotools • The installation of a program is straightforward: ./configure; make; make install • This procedure checks for system parameters, libraries, location of programs, availability of functions and writes a Makefile • ./configure supports many options to overwrite defaults settings

  50. GNU autoconf Source Code configure.ac(configure.in) aclocal autoscan autoconf configure.scan configure

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