source: chapter05/gcc-pass2.xml@ 0efb8e1

multilib-10.1 multilib-before-cross
Last change on this file since 0efb8e1 was 0efb8e1, checked in by Thomas Trepl <thomas@…>, 23 months ago

MultiLib: Merge changes from trunk

git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/multilib@11783 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

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1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4 <!ENTITY % general-entities SYSTEM "../general.ent">
5 %general-entities;
6]>
7
8<sect1 id="ch-tools-gcc-pass2" role="wrap">
9 <?dbhtml filename="gcc-pass2.html"?>
10
11 <sect1info condition="script">
12 <productname>gcc-pass2</productname>
13 <productnumber>&gcc-version;</productnumber>
14 <address>&gcc-url;</address>
15 </sect1info>
16
17 <title>GCC-&gcc-version; - Pass 2</title>
18
19 <indexterm zone="ch-tools-gcc-pass2">
20 <primary sortas="a-GCC">GCC</primary>
21 <secondary>tools, pass 2</secondary>
22 </indexterm>
23
24 <sect2 role="package">
25 <title/>
26
27 <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
28 href="../chapter06/gcc.xml"
29 xpointer="xpointer(/sect1/sect2[1]/para[1])"/>
30
31 <segmentedlist>
32 <segtitle>&buildtime;</segtitle>
33 <segtitle>&diskspace;</segtitle>
34
35 <seglistitem>
36 <seg>&gcc-ch5p2-sbu;</seg>
37 <seg>&gcc-ch5p2-du;</seg>
38 </seglistitem>
39 </segmentedlist>
40
41 </sect2>
42
43 <sect2 role="installation">
44 <title>Installation of GCC</title>
45
46 <para>Our first build of GCC has installed a couple of internal system
47 headers. Normally one of them, <filename>limits.h</filename>, will in turn
48 include the corresponding system <filename>limits.h</filename> header, in
49 this case, <filename>/tools/include/limits.h</filename>. However, at the
50 time of the first build of gcc <filename>/tools/include/limits.h</filename>
51 did not exist, so the internal header that GCC installed is a partial,
52 self-contained file and does not include the extended features of the
53 system header. This was adequate for building the temporary libc, but this
54 build of GCC now requires the full internal header. Create a full version
55 of the internal header using a command that is identical to what the GCC
56 build system does in normal circumstances:</para>
57
58<screen><userinput remap="pre">cat gcc/limitx.h gcc/glimits.h gcc/limity.h &gt; \
59 `dirname $($LFS_TGT-gcc -print-libgcc-file-name)`/include-fixed/limits.h</userinput></screen>
60<!--
61 <para>For x86 machines, the limited number of registers is a bottleneck
62 for the system. Free one up by not using a frame pointer that is not
63 needed:</para>
64
65<screen><userinput remap="pre">case `uname -m` in
66 i?86) sed -i 's/^T_CFLAGS =$/&amp; -fomit-frame-pointer/' gcc/Makefile.in ;;
67esac</userinput></screen>
68-->
69 <para>Once again, change the location of GCC's default dynamic linker to
70 use the one installed in <filename
71 class="directory">/tools</filename>.</para>
72
73<screen><userinput remap="pre">for file in gcc/config/{linux,i386/linux{,64}}.h
74do
75 cp -uv $file{,.orig}
76 sed -e 's@/lib\(64\)\?\(32\)\?\(x32\)\?/ld@/tools&amp;@g' \
77 -e 's@/usr@/tools@g' $file.orig &gt; $file
78 touch $file.orig
79done
80sed -e "/^#define[[:blank:]]*STANDARD_STARTFILE_PREFIX_1/ s;\".*\";\"/tools/lib/\";" \
81 -e "/^#define[[:blank:]]*STANDARD_STARTFILE_PREFIX_2/ s;\".*\";\"\";" \
82 -i gcc/gcc.c</userinput></screen>
83
84 <para arch="default">If building on x86_64, change the default directory
85 name for 64-bit libraries to <quote>lib</quote>:</para>
86
87<screen arch="default"><userinput remap="pre">case $(uname -m) in
88 x86_64)
89 sed -e '/m64=/s/lib64/lib/' \
90 -i.orig gcc/config/i386/t-linux64
91 ;;
92esac</userinput></screen>
93
94 <para arch="ml_32,ml_x32,ml_all">Change the default directory name for 64-bit
95 libraries to <quote>lib</quote>:</para>
96
97<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">sed -e '/m64=/s/lib64/lib/' \
98 -e '/m32=/s/m32=.*/m32=..\/lib32$(call if_multiarch,:i386-linux-gnu)/' \
99 -i.orig gcc/config/i386/t-linux64</userinput></screen>
100
101 <para arch="default">As in the first build of GCC it requires the GMP,
102 MPFR, and MPC packages. Unpack the tarballs and move them into the
103 required directory names:</para>
104
105 <para arch="ml_32,ml_x32,ml_all">As in the first build of GCC it requires the GMP,
106 ISL, MPFR, and MPC packages. Unpack the tarballs and move them into the
107 required directory names:</para>
108
109<screen arch="default"><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
110mv -v mpfr-&mpfr-version; mpfr
111tar -xf ../gmp-&gmp-version;.tar.xz
112mv -v gmp-&gmp-version; gmp
113tar -xf ../mpc-&mpc-version;.tar.gz
114mv -v mpc-&mpc-version; mpc</userinput></screen>
115<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
116mv -v mpfr-&mpfr-version; mpfr
117tar -xf ../gmp-&gmp-version;.tar.xz
118mv -v gmp-&gmp-version; gmp
119tar -xf ../mpc-&mpc-version;.tar.gz
120mv -v mpc-&mpc-version; mpc
121tar -xf ../isl-&isl-version;.tar.xz
122mv -v isl-&isl-version; isl</userinput></screen>
123
124 <para>
125 Now fix a problem introduced by Glibc-2.31:
126 </para>
127
128<screen><userinput remap="pre">sed -e '1161 s|^|//|' \
129 -i libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc</userinput></screen>
130
131 <para>Create a separate build directory again:</para>
132
133<screen><userinput remap="pre">mkdir -v build
134cd build</userinput></screen>
135
136 <para>Before starting to build GCC, remember to unset any environment
137 variables that override the default optimization flags.</para>
138
139 <para>Now prepare GCC for compilation:</para>
140
141<screen><userinput arch="default" remap="configure">mloptions="--disable-multilib"</userinput>
142<userinput arch="ml_32,ml_x32,ml_all" remap="configure">mloptions="--with-system-zlib --enable-multilib --with-multilib-list=m64"</userinput>
143<userinput arch="ml_32,ml_all" remap="configure">mloptions="$mloptions,m32"</userinput>
144<userinput arch="ml_x32,ml_all" remap="configure">mloptions="$mloptions,mx32"</userinput>
145<userinput remap="configure">CC=$LFS_TGT-gcc \
146CXX=$LFS_TGT-g++ \
147AR=$LFS_TGT-ar \
148RANLIB=$LFS_TGT-ranlib \
149../configure \
150 --prefix=/tools \
151 --with-local-prefix=/tools \
152 --with-native-system-header-dir=/tools/include \
153 --enable-languages=c,c++ \
154 --disable-libstdcxx-pch \
155 --disable-bootstrap \
156 --disable-libgomp \
157 $mloptions</userinput></screen>
158
159 <variablelist>
160 <title>The meaning of the new configure options:</title>
161
162 <varlistentry>
163 <term><parameter>--enable-languages=c,c++</parameter></term>
164 <listitem>
165 <para>This option ensures that both the C and C++ compilers are
166 built.</para>
167 </listitem>
168 </varlistentry>
169
170 <varlistentry>
171 <term><parameter>--disable-libstdcxx-pch</parameter></term>
172 <listitem>
173 <para>Do not build the pre-compiled header (PCH) for
174 <filename class="libraryfile">libstdc++</filename>. It takes up a
175 lot of space, and we have no use for it.</para>
176 </listitem>
177 </varlistentry>
178
179 <varlistentry>
180 <term><parameter>--disable-bootstrap</parameter></term>
181 <listitem>
182 <para>For native builds of GCC, the default is to do a "bootstrap"
183 build. This does not just compile GCC, but compiles it several times.
184 It uses the programs compiled in a first round to compile itself a
185 second time, and then again a third time. The second and third
186 iterations are compared to make sure it can reproduce itself
187 flawlessly. This also implies that it was compiled correctly.
188 However, the LFS build method should provide a solid compiler
189 without the need to bootstrap each time.</para>
190 </listitem>
191 </varlistentry>
192
193 </variablelist>
194
195 <para>Compile the package:</para>
196
197<screen><userinput remap="make">make</userinput></screen>
198
199 <para>Install the package:</para>
200
201<screen><userinput remap="install">make install</userinput></screen>
202
203 <para>As a finishing touch, create a symlink. Many programs and scripts
204 run <command>cc</command> instead of <command>gcc</command>, which is
205 used to keep programs generic and therefore usable on all kinds of UNIX
206 systems where the GNU C compiler is not always installed. Running
207 <command>cc</command> leaves the system administrator free to decide
208 which C compiler to install:</para>
209
210<screen><userinput remap="install">ln -sv gcc /tools/bin/cc</userinput></screen>
211
212 <caution>
213 <para>At this point, it is imperative to stop and ensure that the basic
214 functions (compiling and linking) of the new toolchain are working as
215 expected. To perform a sanity check, run the following commands:</para>
216
217<screen><userinput>echo 'int main(){}' &gt; dummy.c
218cc dummy.c
219readelf -l a.out | grep ': /tools'</userinput></screen>
220
221 <para>If everything is working correctly, there should be no errors,
222 and the output of the last command will be of the form:</para>
223
224<screen><computeroutput>[Requesting program interpreter: /tools/lib64/ld-linux-x86-64.so.2]</computeroutput></screen>
225
226
227 <para arch="ml_32,ml_all">Repeat the test for 32-bit:</para>
228
229<screen arch="ml_32,ml_all"><userinput>cc -m32 dummy.c
230readelf -l a.out | grep ': /tools'</userinput></screen>
231
232 <para arch="ml_32,ml_all">In this case, the output shoud be:</para>
233
234<screen arch="ml_32,ml_all"><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</computeroutput></screen>
235
236 <para arch="ml_x32,ml_all">Repeat the test for x32-bit:</para>
237
238<screen arch="ml_x32,ml_all"><userinput>cc -mx32 dummy.c
239readelf -l a.out | grep ': /tools'</userinput></screen>
240
241 <para arch="ml_x32,ml_all">In this case, the output shoud be:</para>
242
243<screen arch="ml_x32,ml_all"><computeroutput>[Requesting program interpreter: /tools/libx32/ld-linux-x32.so.2]</computeroutput></screen>
244
245 <para arch="default">Note that the dynamic linker will be
246 /tools/lib/ld-linux.so.2 for 32-bit machines.</para>
247
248 <para>If the output is not shown as above or there was no output at all,
249 then something is wrong. Investigate and retrace the steps to find out
250 where the problem is and correct it. This issue must be resolved before
251 continuing on. First, perform the sanity check again, using
252 <command>gcc</command> instead of <command>cc</command>. If this works,
253 then the <filename class="symlink">/tools/bin/cc</filename> symlink is
254 missing. Install the symlink as per above.
255 Next, ensure that the <envar>PATH</envar> is correct. This
256 can be checked by running <command>echo $PATH</command> and verifying that
257 <filename class="directory">/tools/bin</filename> is at the head of the
258 list. If the <envar>PATH</envar> is wrong it could mean that you are not
259 logged in as user <systemitem class="username">lfs</systemitem> or that
260 something went wrong back in <xref linkend="ch-preps-settingenviron"
261 role="."/></para>
262
263 <para>Once all is well, clean up the test files:</para>
264
265<screen><userinput>rm -v dummy.c a.out</userinput></screen>
266
267 </caution>
268
269 </sect2>
270
271 <sect2 role="content">
272 <title/>
273
274 <para>Details on this package are located in
275 <xref linkend="contents-gcc" role="."/></para>
276
277 </sect2>
278
279</sect1>
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