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Correct and clarify toolchain explanatory notes. Fixes #2461.

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git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@9021 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
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Matthew Burgess 2009-07-29 20:46:21 +00:00
parent 420a2a2123
commit af9063d6b4
2 changed files with 44 additions and 39 deletions
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5
chapter01/changelog.xml
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@ -39,6 +39,11 @@
<listitem> <listitem>
<para>2009-07-29</para> <para>2009-07-29</para>
<itemizedlist> <itemizedlist>
<listitem>
<para>[matthew] - Correct and clarify some of the explanatory text in
the toolchain technical notes. Fixes
<ulink url="&lfs-ticket-root;2461">#2461</ulink>.</para>
</listitem>
<listitem> <listitem>
<para>[bdubbs] - Updated Acknowledgements. <para>[bdubbs] - Updated Acknowledgements.
Fixes Fixes

78
chapter05/toolchaintechnotes.xml
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@ -17,13 +17,13 @@
to at any time during the process.</para> to at any time during the process.</para>
<para>The overall goal of <xref linkend="chapter-temporary-tools"/> is to <para>The overall goal of <xref linkend="chapter-temporary-tools"/> is to
provide a temporary environment that can be chrooted into and from which can be provide a temporary environment that can be chrooted into,
produced a clean, trouble-free build of the target LFS system in <xref where a clean, trouble-free build of the target LFS system in <xref
linkend="chapter-building-system"/>. Along the way, we separate the new system linkend="chapter-building-system"/> can be produced. Along the way, we
from the host system as much as possible, and in doing so, build a separate the new system from the host system as much as possible, and in
self-contained and self-hosted toolchain. It should be noted that the build doing so, build a self-contained and self-hosted toolchain.
process has been designed to minimize the risks for new readers and provide The build process has been designed to minimize the risks for new
maximum educational value at the same time.</para> readers and to provide the most educational value at the same time.</para>
<important> <important>
<para>Before continuing, be aware of the name of the working platform, <para>Before continuing, be aware of the name of the working platform,
@ -54,11 +54,13 @@
<itemizedlist> <itemizedlist>
<listitem> <listitem>
<para>Slightly adjusting the name of the working platform ensures that <para>Slightly adjusting the name of the working platform, by changing the
the first build of Binutils and GCC produces a compatible cross-linker &quot;vendor&quot; field target triplet by way of the
and cross-compiler. Instead of producing binaries for another architecture, <envar>LFS_TGT</envar> variable, ensures that the first build of Binutils
the cross-linker and cross-compiler will produce binaries compatible with and GCC produces a compatible cross-linker and cross-compiler. Instead of
the current hardware.</para> producing binaries for another architecture, the cross-linker and
cross-compiler will produce binaries compatible with the current
hardware.</para>
</listitem> </listitem>
<listitem> <listitem>
<para>The temporary libraries are cross-compiled. This removes all <para>The temporary libraries are cross-compiled. This removes all
@ -98,9 +100,8 @@
<para>The next package installed is GCC. An example of what can be <para>The next package installed is GCC. An example of what can be
seen during its run of <command>configure</command> is:</para> seen during its run of <command>configure</command> is:</para>
<screen><computeroutput>checking what assembler to use... <screen><computeroutput>checking what assembler to use... /tools/i686-lfs-linux-gnu/bin/as
/tools/i686-pc-linux-gnu/bin/as checking what linker to use... /tools/i686-lfs-linux-gnu/bin/ld</computeroutput></screen>
checking what linker to use... /tools/i686-pc-linux-gnu/bin/ld</computeroutput></screen>
<para>This is important for the reasons mentioned above. It also demonstrates <para>This is important for the reasons mentioned above. It also demonstrates
that GCC's configure script does not search the PATH directories to find which that GCC's configure script does not search the PATH directories to find which
@ -117,34 +118,33 @@ checking what linker to use... /tools/i686-pc-linux-gnu/bin/ld</computeroutput><
<para>The next package installed is Glibc. The most important considerations <para>The next package installed is Glibc. The most important considerations
for building Glibc are the compiler, binary tools, and kernel headers. The for building Glibc are the compiler, binary tools, and kernel headers. The
compiler is generally not an issue since Glibc will always use the compiler is generally not an issue since Glibc will always use the compiler
<command>gcc</command> found in a <envar>PATH</envar> directory. The binary relating to the <parameter>--host</parameter> parameter passed to its
tools and kernel headers can be a bit more complicated. Therefore, take no configure script, e.g. in our case,
risks and use the available configure switches to enforce the correct <command>i686-lfs-linux-gnu-gcc</command>. The binary tools and kernel
selections. After the run of <command>configure</command>, check the contents headers can be a bit more complicated. Therefore, take no risks and use the
of the <filename>config.make</filename> file in the <filename available configure switches to enforce the correct selections. After the run
of <command>configure</command>, check the contents of the
<filename>config.make</filename> file in the <filename
class="directory">glibc-build</filename> directory for all important details. class="directory">glibc-build</filename> directory for all important details.
Note the use of <parameter>CC="gcc -B/tools/bin/"</parameter> to control which Note the use of <parameter>CC="i686-lfs-gnu-gcc"</parameter> to control which
binary tools are used and the use of the <parameter>-nostdinc</parameter> binary tools are used and the use of the <parameter>-nostdinc</parameter> and
and <parameter>-isystem</parameter> flags to control the compiler's include <parameter>-isystem</parameter> flags to control the compiler's include
search path. These items highlight an important aspect of the Glibc search path. These items highlight an important aspect of the Glibc
package&mdash;it is very self-sufficient in terms of its build machinery and package&mdash;it is very self-sufficient in terms of its build machinery and
generally does not rely on toolchain defaults.</para> generally does not rely on toolchain defaults.</para>
<para>After the Glibc installation, make some adjustments to ensure that <para>After the Glibc installation, change <command>gcc</command>'s specs file
searching and linking take place only within the <filename to point to the new dynamic linker in <filename
class="directory">/tools</filename> prefix. Install an adjusted class="directory">/tools/lib</filename>. This last step is vital in ensuring
<command>ld</command>, which has a hard-wired search path limited to that searching and linking take place only within the <filename
<filename class="directory">/tools/lib</filename>. Then amend class="directory">/tools</filename> prefix. A hard-wired
<command>gcc</command>'s specs file to point to the new dynamic linker in path to a dynamic linker is embedded into every Executable and Link Format
<filename class="directory">/tools/lib</filename>. This last step is vital (ELF)-shared executable. This can be inspected by running:
to the whole process. As mentioned above, a hard-wired path to a dynamic
linker is embedded into every Executable and Link Format (ELF)-shared
executable. This can be inspected by running:
<userinput>readelf -l &lt;name of binary&gt; | grep interpreter</userinput>. <userinput>readelf -l &lt;name of binary&gt; | grep interpreter</userinput>.
Amending gcc's specs file ensures that every program compiled from here Amending <command>gcc</command>'s specs file ensures that every program
through the end of this chapter will use the new dynamic linker in compiled from here through the end of this chapter will use the new dynamic
<filename class="directory">/tools/lib</filename>.</para> linker in <filename class="directory">/tools/lib</filename>.</para>
<para>For the second pass of GCC, its sources also need to be modified <para>For the second pass of GCC, its sources also need to be modified
to tell GCC to use the new dynamic linker. Failure to do to tell GCC to use the new dynamic linker. Failure to do
@ -164,8 +164,8 @@ checking what linker to use... /tools/i686-pc-linux-gnu/bin/ld</computeroutput><
linkend="chapter-building-system"/>, the first major package to be linkend="chapter-building-system"/>, the first major package to be
installed is Glibc, due to its self-sufficient nature mentioned above. installed is Glibc, due to its self-sufficient nature mentioned above.
Once this Glibc is installed into <filename Once this Glibc is installed into <filename
class="directory">/usr</filename>, perform a quick changeover of the class="directory">/usr</filename>, we will perform a quick changeover of the
toolchain defaults, then proceed in building the rest of the target toolchain defaults, and then proceed in building the rest of the target
LFS system.</para> LFS system.</para>
<!-- FIXME: Removed as part of the fix for bug 1061 - we no longer build pass1 <!-- FIXME: Removed as part of the fix for bug 1061 - we no longer build pass1