Beyond Linux® From Scratch - Version svn-20070421

Chapter 12. Programming

GCC-4.1.2

Introduction to GCC

The GCC package contains GNU compilers. This package is useful for compiling programs written in C, C++, Fortran, Java, Objective C and Ada. Also included is GNU Treelang. Treelang is a sample language, useful only to help people understand how to implement a new language front end to GCC. It is not a useful language in itself other than as an example or basis for building a new language. Therefore only language developers are likely to have an interest in it.

[Note]

Note

The Fortran compiler included with the GCC-4.x package now aims to be conformant with the Fortran 95 standard, not the Fortran 77 standard as all previous versions of GCC have been. Please note the following paragraph copied directly from the GCC-4.1.2 gfortran man page.

“Gfortran is not yet a fully conformant Fortran 95 compiler. It can generate code for most constructs and expressions, but work remains to be done. In particular, there are known deficiencies with ENTRY, NAMELIST, and sophisticated use of MODULES, POINTERS and DERIVED TYPES. For those whose Fortran codes conform to either the Fortran 77 standard or the GNU Fortran 77 language, we recommend to use g77 from GCC 3.4.x”

Instructions to install the 3.4.6 version of the Fortran compiler can be found in GCC-3.3.6 and on the BLFS Wiki.

Package Information

GCC Dependencies

Recommended

DejaGnu-1.4.4

Optional (Required to Build the Fortran Compiler)

GMP-4.2.1 and MPFR

[Note]

Note

If you plan to compile Ada, you will need to install GNAT temporarily to satisfy the circular dependency when you recompile GCC to include Ada. The download location shown below requires that you create an account on the AdaCore site before you can download the package. Nothing is required other than a valid email address.

Ensure you download the 2005 version of the GNAT compiler. The 2006 version will not work. The file name you need is: gnat-gpl-2005-i686-gnu-linux-gnu-libc2.3-bin.tar.gz.

GNAT GPL 2005 Package Information

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/gcc

Installation of GNAT

Install GNAT by running the following command as the root user: 

make ins-all prefix=/opt/gnat

The GNAT compiler can be invoked by executing the gcc binary installed in /opt/gnat/bin.

You may now remove the GNAT source directory: 

cd .. &&
rm -rf gnat-gpl-2005-i686-gnu-linux-gnu-libc2.3-bin

Prepare to compile GCC by placing the GNAT version of gcc at the beginning of the PATH variable by using the following commands: 

PATH_HOLD=$PATH &&
export PATH=/opt/gnat/bin:$PATH_HOLD

Installation of GCC

Install GCC by running the following commands:

[Important]

Important

The installation process may overwrite your existing GCC gcc and c++ compilers and libraries. It is highly recommended that you have the Tcl, Expect and DejaGnu packages installed before beginning the build so you can run the full suite of tests.

Do not continue with the make install command until you are confident the build was successful. You can compare your test results with those found at http://gcc.gnu.org/ml/gcc-testresults/. There's also an i686 platform test result produced by an LFS-SVN-20070304 system at http://anduin.linuxfromscratch.org/files/BLFS/gcc412_test.txt. You may also want to refer to the information found in the GCC section of Chapter 6 in the LFS book (../../../../lfs/view/development/chapter06/gcc.html).

The instructions below perform a “make bootstrap” instead of just a plain “make” intentionally. Even though it is assumed that the current version of GCC is installed in LFS, because this installation includes the Ada compiler as an installed language, a bootstrap is required. The GNAT compiler must be used for stage1 of the bootstrap in order to build Ada. If the process didn't use a “bootstrap” you could end up having a gcc installed on the system that was produced by a foriegn compiler. 

sed -i 's/install_to_$(INSTALL_DEST) //' libiberty/Makefile.in &&
sed -i 's@\./fixinc\.sh@-c true@' gcc/Makefile.in &&
sed -i 's/@have_mktemp_command@/yes/' gcc/gccbug.in &&
mkdir ../gcc-build &&
cd ../gcc-build &&
../gcc-4.1.2/configure \
    --prefix=/usr \
    --libexecdir=/usr/lib \
    --enable-shared \
    --enable-threads=posix \
    --enable-__cxa_atexit \
    --enable-clocale=gnu \
    --enable-languages=c,c++,ada,fortran,java,objc,treelang &&
make bootstrap &&
make -k check &&
../gcc-4.1.2/contrib/test_summary

Now, as the root user: 

make install &&
ln -v -sf ../usr/bin/cpp /lib &&
ln -v -sf gcc /usr/bin/cc &&
chown -v -R root:root \
    /usr/lib/gcc/i686-pc-linux-gnu/4.1.2/include &&
chown -v -R root:root \
    /usr/lib/gcc/i686-pc-linux-gnu/4.1.2/ada{lib,include}

The libffi interface header is installed in a location where other packages will not be able to find it. If you included Java as one of the installed languages, create a symbolic link in /usr/include to remedy this: 

ln -v -sf `find /usr/lib/gcc -name ffitarget.h` /usr/include

As the root user, remove the GNAT installation: 

rm -rf /opt/gnat

Now, as the unprivileged user, restore your old PATH: 

export PATH=$PATH_HOLD &&
unset PATH_HOLD

Command Explanations

The three sed commands are the same ones used during the build of LFS. A fourth one in LFS is ommitted intentionally, due to the bootstrap build.

mkdir ../gcc-build; cd ../gcc-build: The GCC documentation recommends building the package in a dedicated build directory.

--enable-shared --enable-threads=posix --enable-__cxa_atexit: These parameters are required to build the C++ libraries to published standards.

--enable-clocale=gnu: This command is a failsafe for incomplete locale data.

--enable-languages=c,c++,ada,fortran,java,objc,treelang: This command identifies which languages to build. You may modify this command to remove undesired languages.

make -k check: This command runs the test suite without stopping if any errors are encountered.

../gcc-4.1.2/contrib/test_summary: This command will produce a summary of the test suite results. You can append | grep -A7 Summ to the command to produce an even more condensed version of the summary. You may also wish to redirect the output to a file for review and comparison later on.

ln -v -sf ../usr/bin/cpp /lib: This command creates a link to the C PreProcessor as some packages expect it to be installed in the /lib directory.

ln -v -sf gcc /usr/bin/cc: This link is created as some packages refer to the C compiler using an alternate name.

chown -v -R root:root /usr/lib/gcc/i686-pc-linux-gnu/...: If the package is built by a user other than root, the ownership of the installed include and adalib directories (and their contents) will be incorrect. These commands change the ownership to the root user and group . Omit the command changing the Ada directories if you did not include Ada as one of the installed languages.

Contents

Installed Programs: addr2name.awk, fastjar, gcj, gcj-dbtool,gcjh, gfortran, gij, gjnih, gnat, gnatbind, gnatbl, gnatchop, gnatclean, gnatfind, gnatkr, gnatlink, gnatls, gnatmake, gnatname, gnatprep, gnatxref, gprmake, grepjar, grmic, grmiregistry, gtreelang, jcf-dump, jv-convert, jv-scan and architecture specific names for gcj and gcjh
Installed Libraries: libffi.{so,a}, libgcj.{so,a}, libgfortran.{so,a}, libgfortranbegin.a, libgij.{so,a}, libobjc.{so,a} and numerous other run-time libraries and executables in /usr/lib/gcc
Installed Directories: /usr/include/c++/4.1.2/{gcj,gnu,java,javax,org}, /usr/lib/gcc/i686-pc-linux-gnu/4.1.2/ada{include,lib}, /usr/lib/gcj-4.1.2, /usr/lib/security and /usr/share/java

Some program and library names and descriptions are not listed here, but can be found at ../../../../lfs/view/development/chapter06/gcc.html#contents-gcc as they were initially installed during the building of LFS.

Short Descriptions

addr2name.awk

emulates some of the functionality of addr2line.

fastjar

is an archive tool for Java archives.

gcj

is an ahead-of-time compiler for the Java language.

gcj-dbtool

is a tool for creating and manipulating class file mapping databases.

gcjh

generates header files from Java class files.

gfortran

is the Fortran compiler invoked by gcc.

gij

is the GNU interpreter for Java bytecode.

gjnij

is used to generate JNI header files from class files. Running it is equivalent to running gcjh -jni.

gnat

is the Ada compiler invoked by gcc.

gnatbind

is used to bind compiled objects.

gnatbl

is the Ada linker.

gnatchop

is useful for renaming files to meet the standard Ada default file naming conventions.

gnatclean

is used to remove files associated with a GNAT project.

gnatfind

is the GNAT definition/use finder.

gnatkr

is used to determine the crunched name for a given file, when crunched to a specified maximum length.

gnatlink

is used to link programs and build an executable file.

gnatls

is the compiled unit browser.

gnatmake

is an automatic make facility.

gnatname

will list the files associated with a GNAT project.

gnatprep

is the GNAT external preprocessor.

gnatxref

is the GNAT cross-referencer.

gprmake

is a tool used to create Makefiles that support compilation by multiple languages.

grepjar

searches jar files for a pattern.

grmic

generates stubs for Remote Method Invocation.

grmiregistry

starts a remote object registry on the current host.

gtreelang

is largely a cut down version of C, designed to showcase the features of the GCC code generation back end. Only those features that are directly supported by the GCC code generation back end are implemented. Features are implemented in a manner which is easiest and clearest to implement. Not all or even most code generation back end features are implemented. The intention is to add features incrementally until most features of the GCC back end are implemented in Treelang.

jcf-dump

prints information about Java class files.

jv-convert

converts files from one encoding to another.

jv-scan

prints information about Java source files.

Last updated on 2007-04-04 21:42:53 +0200