source: chapter05/gcc-pass2.xml@ 01ffc23

multilib-10.1 multilib-before-cross
Last change on this file since 01ffc23 was 01ffc23, checked in by Thomas Trepl <thomas@…>, 3 years ago

Merge changes from trunk

git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/multilib@11606 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 echo '
79#undef STANDARD_STARTFILE_PREFIX_1
80#undef STANDARD_STARTFILE_PREFIX_2
81#define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/"
82#define STANDARD_STARTFILE_PREFIX_2 ""' &gt;&gt; $file
83 touch $file.orig
84done</userinput></screen>
85
86 <para arch="default">If building on x86_64, change the default directory
87 name for 64-bit libraries to <quote>lib</quote>:</para>
88
89<screen arch="default"><userinput remap="pre">case $(uname -m) in
90 x86_64)
91 sed -e '/m64=/s/lib64/lib/' \
92 -i.orig gcc/config/i386/t-linux64
93 ;;
94esac</userinput></screen>
95
96 <para arch="ml_32,ml_x32,ml_all">Change the default directory name for 64-bit
97 libraries to <quote>lib</quote>:</para>
98
99<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">sed -e '/m64=/s/lib64/lib/' \
100 -e '/m32=/s/m32=.*/m32=..\/lib32$(call if_multiarch,:i386-linux-gnu)/' \
101 -i.orig gcc/config/i386/t-linux64</userinput></screen>
102
103 <para arch="default">As in the first build of GCC it requires the GMP,
104 MPFR, and MPC packages. Unpack the tarballs and move them into the
105 required directory names:</para>
106
107 <para arch="ml_32,ml_x32,ml_all">As in the first build of GCC it requires the GMP,
108 ISL, MPFR, and MPC packages. Unpack the tarballs and move them into the
109 required directory names:</para>
110
111<screen arch="default"><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
112mv -v mpfr-&mpfr-version; mpfr
113tar -xf ../gmp-&gmp-version;.tar.xz
114mv -v gmp-&gmp-version; gmp
115tar -xf ../mpc-&mpc-version;.tar.gz
116mv -v mpc-&mpc-version; mpc</userinput></screen>
117<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
118mv -v mpfr-&mpfr-version; mpfr
119tar -xf ../gmp-&gmp-version;.tar.xz
120mv -v gmp-&gmp-version; gmp
121tar -xf ../mpc-&mpc-version;.tar.gz
122mv -v mpc-&mpc-version; mpc
123tar -xf ../isl-&isl-version;.tar.xz
124mv -v isl-&isl-version; isl</userinput></screen>
125
126 <!-- Following patch might be obsolete with gcc >= 8.2.1 -->
127 <para arch="ml_32,ml_x32,ml_all">Fix an issue with isl-&isl-version;:</para>
128
129<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">sed -e "/#include &lt;isl\/schedule_node.h&gt;/ a#include &lt;isl/id.h&gt;\n#include &lt;isl/space.h&gt;" \
130 -i gcc/graphite.h</userinput></screen>
131
132 <para>Create a separate build directory again:</para>
133
134<screen><userinput remap="pre">mkdir -v build
135cd build</userinput></screen>
136
137 <para>Before starting to build GCC, remember to unset any environment
138 variables that override the default optimization flags.</para>
139
140 <para>Now prepare GCC for compilation:</para>
141
142<screen><userinput arch="default" remap="configure">mloptions="--disable-multilib"</userinput>
143<userinput arch="ml_32,ml_x32,ml_all" remap="configure">mloptions="--with-system-zlib --enable-multilib --with-multilib-list=m64"</userinput>
144<userinput arch="ml_32,ml_all" remap="configure">mloptions="$mloptions,m32"</userinput>
145<userinput arch="ml_x32,ml_all" remap="configure">mloptions="$mloptions,mx32"</userinput>
146<userinput remap="configure">CC=$LFS_TGT-gcc \
147CXX=$LFS_TGT-g++ \
148AR=$LFS_TGT-ar \
149RANLIB=$LFS_TGT-ranlib \
150../configure \
151 --prefix=/tools \
152 --with-local-prefix=/tools \
153 --with-native-system-header-dir=/tools/include \
154 --enable-languages=c,c++ \
155 --disable-libstdcxx-pch \
156 --disable-bootstrap \
157 --disable-libgomp \
158 $mloptions</userinput></screen>
159
160 <variablelist>
161 <title>The meaning of the new configure options:</title>
162
163 <varlistentry>
164 <term><parameter>--enable-languages=c,c++</parameter></term>
165 <listitem>
166 <para>This option ensures that both the C and C++ compilers are
167 built.</para>
168 </listitem>
169 </varlistentry>
170
171 <varlistentry>
172 <term><parameter>--disable-libstdcxx-pch</parameter></term>
173 <listitem>
174 <para>Do not build the pre-compiled header (PCH) for
175 <filename class="libraryfile">libstdc++</filename>. It takes up a
176 lot of space, and we have no use for it.</para>
177 </listitem>
178 </varlistentry>
179
180 <varlistentry>
181 <term><parameter>--disable-bootstrap</parameter></term>
182 <listitem>
183 <para>For native builds of GCC, the default is to do a "bootstrap"
184 build. This does not just compile GCC, but compiles it several times.
185 It uses the programs compiled in a first round to compile itself a
186 second time, and then again a third time. The second and third
187 iterations are compared to make sure it can reproduce itself
188 flawlessly. This also implies that it was compiled correctly.
189 However, the LFS build method should provide a solid compiler
190 without the need to bootstrap each time.</para>
191 </listitem>
192 </varlistentry>
193
194 </variablelist>
195
196 <para>Compile the package:</para>
197
198<screen><userinput remap="make">make</userinput></screen>
199
200 <para>Install the package:</para>
201
202<screen><userinput remap="install">make install</userinput></screen>
203
204 <para>As a finishing touch, create a symlink. Many programs and scripts
205 run <command>cc</command> instead of <command>gcc</command>, which is
206 used to keep programs generic and therefore usable on all kinds of UNIX
207 systems where the GNU C compiler is not always installed. Running
208 <command>cc</command> leaves the system administrator free to decide
209 which C compiler to install:</para>
210
211<screen><userinput remap="install">ln -sv gcc /tools/bin/cc</userinput></screen>
212
213 <caution>
214 <para>At this point, it is imperative to stop and ensure that the basic
215 functions (compiling and linking) of the new toolchain are working as
216 expected. To perform a sanity check, run the following commands:</para>
217
218<screen><userinput>echo 'int main(){}' &gt; dummy.c
219cc dummy.c
220readelf -l a.out | grep ': /tools'</userinput></screen>
221
222 <para>If everything is working correctly, there should be no errors,
223 and the output of the last command will be of the form:</para>
224
225<screen><computeroutput>[Requesting program interpreter: /tools/lib64/ld-linux-x86-64.so.2]</computeroutput></screen>
226
227
228 <para arch="ml_32,ml_all">Repeat the test for 32-bit:</para>
229
230<screen arch="ml_32,ml_all"><userinput>cc -m32 dummy.c
231readelf -l a.out | grep ': /tools'</userinput></screen>
232
233 <para arch="ml_32,ml_all">In this case, the output shoud be:</para>
234
235<screen arch="ml_32,ml_all"><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</computeroutput></screen>
236
237 <para arch="ml_x32,ml_all">Repeat the test for x32-bit:</para>
238
239<screen arch="ml_x32,ml_all"><userinput>cc -mx32 dummy.c
240readelf -l a.out | grep ': /tools'</userinput></screen>
241
242 <para arch="ml_x32,ml_all">In this case, the output shoud be:</para>
243
244<screen arch="ml_x32,ml_all"><computeroutput>[Requesting program interpreter: /tools/libx32/ld-linux-x32.so.2]</computeroutput></screen>
245
246 <para arch="default">Note that the dynamic linker will be
247 /tools/lib/ld-linux.so.2 for 32-bit machines.</para>
248
249 <para>If the output is not shown as above or there was no output at all,
250 then something is wrong. Investigate and retrace the steps to find out
251 where the problem is and correct it. This issue must be resolved before
252 continuing on. First, perform the sanity check again, using
253 <command>gcc</command> instead of <command>cc</command>. If this works,
254 then the <filename class="symlink">/tools/bin/cc</filename> symlink is
255 missing. Install the symlink as per above.
256 Next, ensure that the <envar>PATH</envar> is correct. This
257 can be checked by running <command>echo $PATH</command> and verifying that
258 <filename class="directory">/tools/bin</filename> is at the head of the
259 list. If the <envar>PATH</envar> is wrong it could mean that you are not
260 logged in as user <systemitem class="username">lfs</systemitem> or that
261 something went wrong back in <xref linkend="ch-tools-settingenviron"
262 role="."/></para>
263
264 <para>Once all is well, clean up the test files:</para>
265
266<screen><userinput>rm -v dummy.c a.out</userinput></screen>
267
268 </caution>
269
270 </sect2>
271
272 <sect2 role="content">
273 <title/>
274
275 <para>Details on this package are located in
276 <xref linkend="contents-gcc" role="."/></para>
277
278 </sect2>
279
280</sect1>
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