diff options
Diffstat (limited to 'chapter05/gcc-pass1-inst.xml')
| -rw-r--r-- | chapter05/gcc-pass1-inst.xml | 97 |
1 files changed, 38 insertions, 59 deletions
diff --git a/chapter05/gcc-pass1-inst.xml b/chapter05/gcc-pass1-inst.xml index b290d05f2..e9a649776 100644 --- a/chapter05/gcc-pass1-inst.xml +++ b/chapter05/gcc-pass1-inst.xml @@ -3,7 +3,7 @@ <sect2> <title>Installation of GCC</title> -<para>We won't be needing a C++ compiler until Chapter 6. So, only +<para>We won't be needing a C++ compiler until the next chapter. So, only the gcc-core tarball needs to be unpacked at this time.</para> <para>This package is known to behave badly when you have changed its @@ -28,79 +28,58 @@ cd ../gcc-build</userinput></screen></para> --disable-nls --enable-shared \ --enable-languages=c</userinput></screen></para> -<para>The meaning of the configure options are:</para> +<para>The meaning of the new configure options is:</para> <itemizedlist> -<listitem><para><userinput>--prefix=/static</userinput>: This is NOT a -typo. GCC hard codes some paths while compiling and so we need to pass -<filename class="directory">/static</filename> as the prefix during the -configure stage. We will pass the real installation prefix (<filename -class="directory">$LFS/static</filename>) during the installation -stage later on.</para></listitem> - -<listitem><para><userinput>--disable-shared</userinput>: This prevents the -build of dynamic libraries. They are useless to us at the moment. We'll -create them when we reinstall GCC in chapter 6.</para></listitem> - -<listitem><para><userinput>--with-as=$LFS/static/bin/as and ---with-ld=$LFS/static/bin/ld</userinput>: GCC can be miscompiled if your -host distribution's Binutils package is quite old. We need a good working -static GCC until we reinstall GCC later in chapter 6. So by using -<filename>as</filename> and <filename>ld</filename> from the Binutils -package we compiled earlier in this chapter we ensure that GCC will work -correctly.</para></listitem> +<listitem><para><userinput>--with-local-prefix=/stage1</userinput>: The +purpose of this switch is to remove <filename>/usr/local/include</filename> +from <userinput>gcc</userinput>'s include search path. This is not absolutely +essential, but we want to try and minimize the influence from the host system, +so this seems a logical thing to do.</para></listitem> + +<listitem><para><userinput>--enable-shared</userinput>: This switch may +seem counter-intuitive at first. But using it allows the building of +<filename>libgcc_s.so.1</filename> and <filename>libgcc_eh.a</filename>, and +having <filename>libgcc_eh.a</filename> available ensures that the configure +script for Glibc (the next package we compile) produces the proper results. +Please note that the <userinput>gcc</userinput> binaries will still be linked +statically, as this is controlled by the <userinput>-static</userinput> +value of BOOT_LDFLAGS further on.</para></listitem> + +<listitem><para><userinput>--enable-languages=c</userinput>: This will build +only the C compiler from the GCC package. We won't be needing anything else +during this chapter.</para></listitem> </itemizedlist> <para>Continue with compiling the package:</para> <para><screen><userinput>make BOOT_LDFLAGS="-static" bootstrap</userinput></screen></para> -<para>The meaning of the make options are:</para> +<para>The meaning of the make parameters is:</para> <itemizedlist> -<listitem><para><userinput>BOOT_LDFLAGS="-static"</userinput>: This is -GCC's equivalent to make LDFLAGS="-static" as we use with other packages to -compile them statically.</para></listitem> - -<listitem><para><userinput>bootstrap</userinput>: The -<emphasis>bootstrap</emphasis> target doesn't just compile GCC, but it -compiles GCC a second time. It uses the first compiled programs to compile -itself a second and third time to make sure the compiler was compiled properly -and can compile itself properly.</para></listitem> +<listitem><para><userinput>BOOT_LDFLAGS="-static"</userinput>: This tells +GCC to link its programs statically.</para></listitem> + +<listitem><para><userinput>bootstrap</userinput>: This target doesn't just +compile GCC, but compiles it several times. It uses the programs compiled in +a first round to compile itself a second time, and then again a third time. +It then compares these second and third compiles to make sure it can +reproduce itself flawlessly, which most probably means that it was +compiled correctly.</para></listitem> </itemizedlist> -<para>And finish off installing the package:</para> +<para>And install the package:</para> <para><screen><userinput>make install</userinput></screen></para> -<para>The meaning of the make option is:</para> - -<itemizedlist> -<listitem><para><userinput>install-no-fixedincludes</userinput>: This prevents -the fixincludes script from running. Preventing this is necessary because -under normal circumstances the GCC installation will run the fixincludes -script which scans your system for header files that need to be fixed. It -might find that the Glibc header files of your host system need to be fixed. -If so, it will fix them and put them in -<filename>$LFS/static/lib/gcc-lib/i686-pc-linux-gnu/3.2</filename>. Later on -in chapter 6 you will install Glibc which will put its header files in -<filename>/usr/include</filename>. Next you will install other programs that -use the Glibc headers and GCC will look in -<filename>/static/lib/gcc-lib</filename> before looking in -<filename>/usr/include</filename>, with the result of finding and using the -fixed Glibc header files from your host distribution, which are probably -incompatible with the Glibc version actually used on the LFS -system.</para></listitem> -</itemizedlist> - -<para>As the finishing touch we'll create the <filename -class="symlink">$LFS/static/bin/cc</filename> symlink. A lot of programs -and scripts try to run <userinput>cc</userinput> instead of -<userinput>gcc</userinput> This is to keep programs generic and usable on -all kinds of Unix systems. Not everybody has GNU CC installed. Just running -<userinput>cc</userinput> (C Compiler) leaves the user free to decide which -C compiler to install. The symlink will point to the system's default -compiler.</para> +<para>As a finishing touch we'll create the <filename +class="symlink">/stage1/bin/cc</filename> symlink. Many programs and +scripts run <userinput>cc</userinput> instead of <userinput>gcc</userinput>, +a thing meant to keep programs generic and therefore usable on all kinds of +Unix systems. Not everybody has the GNU C compiler installed. Simply running +<userinput>cc</userinput> leaves the system administrator free to decide what +C compiler to install, as long as there's a symlink pointing to it:</para> <para><screen><userinput>ln -sf gcc /stage1/bin/cc</userinput></screen></para> |