Solution to Problem 2:
----------------------

        Initially copy the file "bb.py" to the build directory, this is 
        the tool  we will be  using and is  among the resources  of the 
        assignment, then open  terminal go to the  $BUILD directory and 
        run the given tool in interactive mode,                         
                        
                       $ ./bb.py -i -s $SOURCE

        once the tool  has started, type insn-output.c for  name of file
        and for level enter 3, this will generate following tree.


        $BUILD/gcc/insn-output.c
        |--$BUILD/gcc/tmp-output.c
        |--|--$BUILD/gcc/build/genoutput
        |--|--|--$BUILD/build-i686-pc-linux-gnu/libiberty/libiberty.a
        |--|--|--$BUILD/gcc/build/errors.o
        |--|--|--$BUILD/gcc/build/genoutput.o
        |--|--|--$BUILD/gcc/build/gensupport.o
        |--|--|--$BUILD/gcc/build/ggc-none.o
        |--|--|--$BUILD/gcc/build/min-insn-modes.o
        |--|--|--$BUILD/gcc/build/print-rtl.o
        |--|--|--$BUILD/gcc/build/read-md.o
        |--|--|--$BUILD/gcc/build/read-rtl.o
        |--|--|--$BUILD/gcc/build/rtl.o
        |--|--|--$BUILD/gcc/build/vec.o
        |--|--$BUILD/gcc/insn-conditions.md
        |--|--|--$BUILD/gcc/tmp-cond.md
        |--|--/home/sumit/Gcc/Extractions/gcc-4.6.2/gcc/config/spim/spim1.md

        NOTE:Here "/home/sumit/Gcc/Extractions/gcc-4.6.2/" is $SOURCE directory


        As you can see the insn-output.c is dependent on genoutput which
        is an  executable file which  when run  makes use of  the target
        machine's  `.md' files,  and generate  insn-output.c. Among  the
        dependencies you will find  insn-conditons.md. This file is also
        generated at build time of gcc and is target machine dependent.

        Similarly we can generate trees for insn-emit.c and insn-recog.c

        $BUILD/gcc/insn-recog.c
        |--$BUILD/gcc/tmp-recog.c
        |--|--$BUILD/gcc/build/genrecog
        |--|--|--$BUIfLD/build-i686-pc-linux-gnu/libiberty/libiberty.a
        |--|--|--$BUILD/gcc/build/errors.o
        |--|--|--$BUILD/gcc/build/genrecog.o
        |--|--|--$BUILD/gcc/build/gensupport.o
        |--|--|--$BUILD/gcc/build/ggc-none.o
        |--|--|--$BUILD/gcc/build/min-insn-modes.o
        |--|--|--$BUILD/gcc/build/print-rtl.o
        |--|--|--$BUILD/gcc/build/read-md.o
        |--|--|--$BUILD/gcc/build/read-rtl.o
        |--|--|--$BUILD/gcc/build/rtl.o
        |--|--|--$BUILD/gcc/build/vec.o
        |--|--$BUILD/gcc/insn-conditions.md
        |--|--|--$BUILD/gcc/tmp-cond.md
        |--|--/home/sumit/Gcc/Extractions/gcc-4.6.2/gcc/config/spim/spim1.md


        $BUILD/gcc/insn-emit.c
        |--$BUILD/gcc/tmp-emit.c
        |--|--$BUILD/gcc/build/genemit
        |--|--|--$BUILD/build-i686-pc-linux-gnu/libiberty/libiberty.a
        |--|--|--$BUILD/gcc/build/errors.o
        |--|--|--$BUILD/gcc/build/genemit.o
        |--|--|--$BUILD/gcc/build/gensupport.o
        |--|--|--$BUILD/gcc/build/ggc-none.o
        |--|--|--$BUILD/gcc/build/min-insn-modes.o
        |--|--|--$BUILD/gcc/build/print-rtl.o
        |--|--|--$BUILD/gcc/build/read-md.o
        |--|--|--$BUILD/gcc/build/read-rtl.o
        |--|--|--$BUILD/gcc/build/rtl.o
        |--|--|--$BUILD/gcc/build/vec.o
        |--|--$BUILD/gcc/insn-conditions.md
        |--|--|--$BUILD/gcc/tmp-cond.md
        |--|--/home/sumit/Gcc/Extractions/gcc-4.6.2/gcc/config/spim/spim1.md



        Both  of these  files also  have  a similar  dependency tree  as
        insn-output.c.  That  means these  files  are  generated in  the
        similar manner  i.e. by an  exeutable which makes use  of target
        machine`s md file.


        There is one important thing  to notice here that whatever files
        was generated from  the gen* executable files have  names of the
        format tmp-* which are then renamed to insn-*. For example:
        tmp-output.c ===>>> insn-output.c
         tmp-recog.c ===>>> insn-recog.c
          tmp-emit.c ===>>> insn-emit.c

Solution to Problem 3:
---------------------

        Now to  find out  other similar files  which are  target machine
        dependent we will  have to open run the tool  in reverse mapping
        interactive mode, open a new tab in the terminal and type

                        ./bb.py -i -r -s ./../gcc-4.6.2/

        because of  the -r switch the  tool can now be  used for reverse
        mapping mode. For the file name  use spim1.md and for level type
        2. This will generate the following result.

        /home/sumit/Gcc/Extractions/gcc-4.6.2/gcc/config/spim/spim1.md
        ^--$BUILD/gcc/tmp-attrtab.c
        ^--^--$BUILD/gcc/insn-attrtab.c
        ^--$BUILD/gcc/tmp-automata.c
        ^--^--$BUILD/gcc/insn-automata.c
        ^--$BUILD/gcc/tmp-condmd.c
        ^--^--$BUILD/gcc/build/gencondmd.c
        ^--$BUILD/gcc/tmp-emit.c
        ^--^--$BUILD/gcc/insn-emit.c
        ^--$BUILD/gcc/tmp-enums.c
        ^--^--$BUILD/gcc/insn-enums.c
        ^--$BUILD/gcc/tmp-extract.c
        ^--^--$BUILD/gcc/insn-extract.c
        ^--$BUILD/gcc/tmp-opinit.c
        ^--^--$BUILD/gcc/insn-opinit.c
        ^--$BUILD/gcc/tmp-output.c
        ^--^--$BUILD/gcc/insn-output.c
        ^--$BUILD/gcc/tmp-peep.c
        ^--^--$BUILD/gcc/insn-peep.c
        ^--$BUILD/gcc/tmp-preds.c
        ^--^--$BUILD/gcc/insn-preds.c
        ^--$BUILD/gcc/tmp-recog.c
        ^--^--$BUILD/gcc/insn-recog.c


        The above  is the list of  all the files where  spim1.md is used
        while building  the gcc compilor  providing us with  the details
        about the target machine dependent part of gcc.

        As one can observe all  the object files generated are dependent
        on the  source files which  are from the build  directory itself
        and on obeserving the depedency tree of the all the above files,
        using the tool  in normal interactive mode, one  can easily find
        out that they all were generated at build time.