Complete cross compilation example

by AUGER Mickael (from France)

This document gives an example of complete and sample program (named myproject) using some modules (Configuration) of LibU. The compilation use MaKL and a custom cross compilation for ARM. MaKL and LibU are install only in the user folder (/home/ma/myproject/ in the example).

Part 1 : local installation of MaKL

Objective : configure and install MaKL in the user folder. This installation of MaKL is independent of the target.

• Download the last version of MaKL (here 1.9.0) - Instead of type all command line in shell, create a script such as

    #!/bin/sh
    ### install_makl.sh ###
    GNUMAKE=make
    LOCAL_DIR=`pwd`
    #here LOCAL_DIR=/home/ma/myproject
  
    V_MAKL=1.9.0
    MAKL_DIR=$LOCAL_DIR/makl
    MAKL_BIN=$MAKL_DIR/bin
  
    tar zxvf makl-${V_MAKL}.tar.gz
    cd makl-${V_MAKL}/
    ${GNUMAKE} toolchain
    ./configure --gnu_make=${GNUMAKE} --prefix="${MAKL_DIR}"
    ${GNUMAKE} install
    

• Execute : ./install_makl.sh - Add the binary folder of MaKL in your PATH

    export PATH="${PATH}:${MAKL_BIN}"
    

Part 2 : create a toolchain file

In this example, we compile for the ARM architecture. Here the binary are in /home/public/arm-2007q3/bin/.

• Create .tc file

    ### arm.tc ###
    XC_BASE = /home/public/arm-2007q3/bin
    ARM_CFLAGS = -Wunused-variable -Wunused-parameter -Wunused-function
    #compile pour gdb
    #ARM_CFLAGS = -g -Wunused-variable -Wunused-parameter -Wunused-function
    ARM_CXXFLAGS = ${ARM_CFLAGS}
  
    CC = ${XC_BASE}/arm-none-linux-gnueabi-gcc ${ARM_CFLAGS}
    CXX = ${XC_BASE}/arm-none-linux-gnueabi-g++ ${ARM_CXXFLAGS}
    AR = ${XC_BASE}/arm-none-linux-gnueabi-ar
    RANLIB = ${XC_BASE}/arm-none-linux-gnueabi-ranlib
    LD = ${XC_BASE}/arm-none-linux-gnueabi-ld
    NM = ${XC_BASE}/arm-none-linux-gnueabi-nm
    STRIP =
    INSTALL_STRIP =
    

Part 3 : local installation of LibU

Objective : configure and install LibU in the user folder.

• Download the last version of LibU (here 2.2.0) - Instead of type all command line in shell, create a script such as

    #!/bin/sh
    ### install_libu.sh ###
    GNUMAKE=make
    LOCAL_DIR=`pwd`
  
    V_LIBU=2.2.0
    LIBU_DIR=$LOCAL_DIR/libu
  
    tar zxvf libu-${V_LIBU}.tar.gz
    cd libu-${V_LIBU}/
  
    #we can disabled all unused modules of LibU
    #and specifiy cross_compile to disabled test
    makl-conf --prefix="${LIBU_DIR}" --no_hmap --no_net --no_env --no_fs --no_pwd --no_list --no_array --no_ringbuffer --no_pqueue --no_json --no_bst --cross_compile
  
    makl --makl-tc-file=${LOCAL_DIR}/arm.tc --makl-tc-onthefly
    makl install
    

• Execute

    ./install_libu.sh
    

Now, we can create our project !

Part 4 : create the project

Our project will be very minimal : - one library (named mylib) - one main source file (program and named myproject)

MaKL can create a template for each type of package : include, program, library, man ... We use it like this (see also MaKL Wiki for more information)

• Create the main Makefile and the tree of folder

    mkdir mylib program include
    makl-new subdir
    

• Edit Makefile to add SUBDIR, CFLAGS and LDADD such as

    SUBDIR = include mylib program
    CFLAGS += $(LIBU_CFLAGS)
    LDADD += $(LIBU_LDADD)
  
    include subdir.mk
    

• Create a VERSION file that contains the version of our project (here 1.0.0)

    1.0.0
    

• Init include folder

    cd include
    makl-new include
    

• Edit include/Makefile to add INCS such as

    include common.mk
    include ../Makefile.conf
  
    INCS = mylib.h
  
    include incs.mk
    

• Create a new file mylib.h in include such as

    #ifndef MYLIB_H
    #define MYLIB_H
  
    #include "conf.h"
  
    #include 
    /*
    add here the other include
    */
  
    void hello();
    #endif
    

• Init mylib folder

    cd mylib
    makl-new lib
    

• Edit mylib/Makefile to add LIB, SRCS, CFLAGS ... such as

    include common.mk
    include ../Makefile.conf
  
    LIB = mylib
    SRCS = mylib.c
  
    CFLAGS += -I../include
    CFLAGS += $(LIBU_CFLAGS)
    LDADD += $(LIBU_LDADD)
  
    include lib.mk
    

• Create a new file mylib.c in mylib such as

    #include "mylib.h"
  
    void hello()
    {
      u_con("Hello LibU world !");
    }
    

• Init program folder

    cd program
    makl-new prog
    

• Edit program/Makefile to add PROG, SRCS, CFLAGS ... such as

    include common.mk
    include ../Makefile.conf
  
    PROG = myproject
    SRCS = main.c
  
    #LDFLAGS += __SETME__
    CFLAGS += $(LIBU_CFLAGS)
    CFLAGS += -I../include
    LDADD += $(LIBU_LDADD)
    LDADD += ../mylib/libmylib.a
  
    include prog.mk
    

• Create a new file main.c in program such as

    #include "mylib.h"
  
    int facility = LOG_LOCAL0;
  
    int main(int argc, char *argv[])
    {
      printf("VERSION=%s\n",MYPROJECT_VERSION);
      
      hello();
      
      /*
      for example, use the Configuration module of LibU
      */
      
      return 0;
    }
    

At this step, the contents of /home/ma/myproject/ is such as :

- /home/ma/myproject/
-- include
--- Makefile
--- mylib.h
-- program
--- Makefile
--- main.c
-- mylib
--- mylib.c
--- Makefile
-- libu
--- ... installation of LibU
-- libu-2.2.0
--- ... source of LibU
-- makl
--- ... installation of MaKL
-- makl-1.9.0
--- ... source of MaKL
-- Makefile
-- arm.tc
-- VERSION

Part 5 : configure the project

Objective : configure the project for the target.

• Create a file such as – This file will be automatically use by MaKL

    #!/bin/sh
    ### configure.sh ###
  
    GNUMAKE=make
    LOCAL_DIR=`pwd`
  
    V_MAKL=1.9.0
    MAKL_DIR=$LOCAL_DIR/makl
    MAKL_BIN=$MAKL_DIR/bin
    LIBU_DIR=$LOCAL_DIR/libu
    MAKL_DIR=${MAKL_DIR}/share/makl-${V_MAKL}
  
    . "${MAKL_DIR}"/cf/makl.init
    makl_args_init "$@"
  
    makl_pkg_name "xtc_utilities"
    makl_pkg_version
  
    makl_set_var_mk "LOCALDIR" "${LOCAL_DIR}"
    makl_append_var_mk "CFLAGS" "-I\$(LOCALDIR)"
    makl_append_var_mk "CFLAGS" "-I\$(LOCALDIR)/include"
  
    makl_set_var_mk "LIBUDIR" "${LIBU_DIR}"
    makl_append_var_mk "LIBU_CFLAGS" "-I\$(LIBUDIR)/include"
    makl_append_var_mk "LIBU_LDADD" "\$(LIBUDIR)/lib/libu.a"
  
    . "${MAKL_DIR}"/cf/makl.term
    

• Instead of type all command line in shell, create a script such as

    #!/bin/sh
    ### config_project.sh ###
    GNUMAKE=make
    LOCAL_DIR=`pwd`
  
    LIBU_DIR=$LOCAL_DIR/libu
  
    makl-conf --lib-u=${LIBU_DIR}
    

• Execute ./config_project.sh – This execution create a Makefile.conf and conf.h

Part 6 : compile the project

The compilation is the more simple operation :

makl --makl-tc-file=${LOCAL_DIR}/arm.tc --makl-tc-onthefly clean all

• This only command line will be call after each modification of source