GCC-12.2.0
Introduction to GCC
The GCC package contains the GNU
Compiler Collection. This page describes the installation of
compilers for the following languages: C, C++, Fortran, Objective
C, Objective C++, and Go. Since C and C++ are installed in LFS,
this page is either for upgrading C and C++, or for installing
additional compilers.
![[Note]](../images/note.png)
Note
Additional languages, among which D and ADA, are available in the
collection. D and ADA have a binary bootstrap requirement for the
first installation, so their installation is not described here.
To install them, you can proceed along the same lines as below
after installing the corresponding compiler from a binary
package, adding ada or d to the --enable-languages line.
This package is known to build and work properly using an LFS 11.3
platform.
![[Caution]](../images/caution.png)
Caution
If you are upgrading GCC from
any other version prior to 12.2.0, then you must be careful
compiling 3rd party kernel modules. You should ensure that the
kernel and all its native modules are also compiled using the
same version of GCC that you use
to build the 3rd party module. This issue does not affect native
kernel (and kernel modules) updates, as the instructions below
are a complete reinstallation of GCC. If you have existing 3rd party modules
installed, ensure they are recompiled using the updated version
of GCC. As always, never update
the kernel headers from the ones used when Glibc was compiled during LFS.
Some system headers need to be fixed to be used with GCC. This is
done during the installation of GCC, and the “fixed”
headers are installed in /usr/lib/gcc/<machine triplet>/<GCC
version>/include-fixed . This is harmless if GCC is
built during the LFS stage. But if you reinstall GCC in BLFS,
some of the BLFS packages may be “fixed”. If
one of those packages is reinstalled afterwards, the “fixed”
headers are not updated, which may lead to version mismatches. In
case that happens, the “fixed” headers must be updated by
running (as root): /usr/libexec/gcc/x86_64-pc-linux-gnu/12.2.0/install-tools/mkheaders
. The machine triplet may be different on a 32-bit system.
Package Information
GCC Dependencies
Optional
GDB-13.1,
Valgrind-3.20.0 (for tests), and ISL (to enable
graphite optimization)
User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/gcc
Installation of GCC
![[Important]](../images/important.png)
Important
Even if you specify only languages other than C and C++ to the
./configure command
below, the installation process will overwrite your existing
GCC C and C++ compilers and
libraries. Running the full suite of tests is recommended.
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 https://gcc.gnu.org/ml/gcc-testresults/.
You may also want to refer to the information found in the
GCC section of Chapter 8 in the
LFS book (../../../../lfs/view/11.3/chapter08/gcc.html).
The instructions below are intentionally performing a “bootstrap”
process. Bootstrapping is needed for robustness and is highly
recommended when upgrading the compilers version. To disable
bootstrap anyway, add --disable-bootstrap to the
./configure options
below.
Install GCC by running the
following commands:
case $(uname -m) in
x86_64)
sed -i.orig '/m64=/s/lib64/lib/' gcc/config/i386/t-linux64
;;
esac
mkdir build &&
cd build &&
../configure \
--prefix=/usr \
--disable-multilib \
--with-system-zlib \
--enable-default-pie \
--enable-default-ssp \
--enable-languages=c,c++,fortran,go,objc,obj-c++ &&
make
If you have installed additional packages such as Valgrind and GDB, the GCC
part of the test suite will run more tests than in LFS. Some of
those will report FAIL and others XPASS (pass when expected to
FAIL). As of gcc-12.2.0, about 60 FAIL occur in the “guality”
suite, as well as miscellaneous failures throughout the rest of the
test suite, fifteen of which are already present in the GCC tests
of LFS. If all the compilers above are built, there will be around
80 unexpected failures out of over 482,000 tests. To run the tests,
issue:
ulimit -s 32768 &&
make -k check
The tests are very long, and the results may be hard to find in the
logs, specially if you use parallel jobs with make. You can get a
summary of the tests with:
../contrib/test_summary
Now, as the root user:
make install &&
mkdir -pv /usr/share/gdb/auto-load/usr/lib &&
mv -v /usr/lib/*gdb.py /usr/share/gdb/auto-load/usr/lib &&
chown -v -R root:root \
/usr/lib/gcc/*linux-gnu/12.2.0/include{,-fixed}
Some packages expect to find the C preprocessor in /lib or may refer to the C compiler under the
name cc. The
following symbolic links are not needed if you have followed the
LFS instructions, since they have been already created. If you do
not have them on your system, issue as the root user:
ln -v -sf ../usr/bin/cpp /lib &&
ln -v -sf gcc /usr/bin/cc &&
install -v -dm755 /usr/lib/bfd-plugins &&
ln -sfv ../../libexec/gcc/$(gcc -dumpmachine)/12.2.0/liblto_plugin.so /usr/lib/bfd-plugins/
Command Explanations
mkdir build; cd
build: The GCC
documentation recommends building the package in a dedicated build
directory.
--disable-multilib: This
parameter ensures that files are created for the specific
architecture of your computer.
--with-system-zlib: Uses
the system zlib instead of the
bundled one. zlib is used for
compressing and decompressing GCC's intermediate language in LTO (Link Time
Optimization) object files.
--enable-default-pie: Makes
the -fpie option the default when
compiling programs. Together with the ASLR feature enabled in the kernel, this
defeats some kind of attacks based on known memory layouts.
--enable-default-ssp: Makes
the -fstack-protector-strong option the
default when compiling programs. SSP is a technique preventing alteration of
the program flow by corrupting the parameter stack.
--enable-languages=c,c++,fortran,go,objc,obj-c++:
This command identifies which languages to build. You may modify
this command to remove undesired languages. Other languages can be
added, including ADA, D, BRIG (add brig to the list of enabled
languages), a binary format for HSAIL (Heterogeneous System
Architecture Intermediate Language), and JIT (add jit to the list of enabled
languages), a library which can be linked into interpreters that
want to generate machine code “on the fly”
at run-time. They have not been tested by the BLFS developers.
ulimit -s 32768: This
command prevents several tests from running out of stack space.
make -k check: This
command runs the test suite without stopping if any errors are
encountered.
../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.
mv -v /usr/lib/*gdb.py
...: The installation stage puts some files used by
gdb under the /usr/lib directory. This generates spurious error
messages when performing ldconfig. This command moves the
files to another location.
chown -v -R root:root
/usr/lib/gcc/*linux-gnu/...: If the package is
built by a user other than root, the ownership of the installed
include directory (and its content)
will be incorrect. This command changes the ownership to the
root user and group.
Contents
Some program and library names and descriptions are not listed
here, but can be found at LFS
section for GCC as they were initially installed during the
building of LFS.
Installed Programs:
gccgo, gfortran, go, and gofmt,
hard-linked to architecture specific names
Installed Libraries:
libgfortran.{so,a}, libgo.{so,a},
libgobegin.a, libgolibbegin.a, libobjc.{so,a}, and numerous
other run-time libraries and executables
Installed Directories:
/usr/lib/go
Short Descriptions
|
gccgo
|
is a GCC-based compiler for the Go language
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|
go
|
is a tool for managing Go source code
|
|
gofmt
|
is a tool for formatting Go source code
|
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gfortran
|
is a GCC-based compiler for the Fortran language
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