source: chapter05/gcc-pass2.xml@ ee1a413

multilib-10.1 multilib-before-cross
Last change on this file since ee1a413 was ee1a413, checked in by Thomas Trepl <thomas@…>, 3 years ago

Change profiling attribute to enable selection of m32 and/or mx32. Fixes #4452.

git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/multilib@11571 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

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File size: 12.2 KB
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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</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 -i.orig gcc/config/i386/t-linux64
101cat > gcc/config/i386/t-linux64 &lt;&lt;"EOF"
102comma=,
103MULTILIB_OPTIONS = $(subst $(comma),/,$(TM_MULTILIB_CONFIG))
104MULTILIB_DIRNAMES = $(patsubst m%, %, $(subst /, ,$(MULTILIB_OPTIONS)))
105MULTILIB_OSDIRNAMES = m64=../lib$(call if_multiarch,:x86_64-linux-gnu)
106MULTILIB_OSDIRNAMES+= m32=../lib32$(call if_multiarch,:i386-linux-gnu)
107MULTILIB_OSDIRNAMES+= mx32=../libx32$(call if_multiarch,:x86_64-linux-gnux32)
108EOF</userinput></screen>
109
110 <para arch="default">As in the first build of GCC it requires the GMP,
111 MPFR, and MPC packages. Unpack the tarballs and move them into the
112 required directory names:</para>
113
114 <para arch="ml_32,ml_x32,ml_all">As in the first build of GCC it requires the GMP,
115 ISL, MPFR, and MPC packages. Unpack the tarballs and move them into the
116 required directory names:</para>
117
118<screen arch="default"><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
119mv -v mpfr-&mpfr-version; mpfr
120tar -xf ../gmp-&gmp-version;.tar.xz
121mv -v gmp-&gmp-version; gmp
122tar -xf ../mpc-&mpc-version;.tar.gz
123mv -v mpc-&mpc-version; mpc</userinput></screen>
124<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">tar -xf ../mpfr-&mpfr-version;.tar.xz
125mv -v mpfr-&mpfr-version; mpfr
126tar -xf ../gmp-&gmp-version;.tar.xz
127mv -v gmp-&gmp-version; gmp
128tar -xf ../mpc-&mpc-version;.tar.gz
129mv -v mpc-&mpc-version; mpc
130tar -xf ../isl-&isl-version;.tar.xz
131mv -v isl-&isl-version; isl</userinput></screen>
132
133 <!-- Following patch might be obsolete with gcc >= 8.2.1 -->
134 <para arch="ml_32,ml_x32,ml_all">Fix an issue with isl-&isl-version;:</para>
135
136<screen arch="ml_32,ml_x32,ml_all"><userinput remap="pre">sed -e "/#include &lt;isl\/schedule_node.h&gt;/ a#include &lt;isl/id.h&gt;\n#include &lt;isl/space.h&gt;" \
137 -i gcc/graphite.h</userinput></screen>
138
139 <para>Create a separate build directory again:</para>
140
141<screen><userinput remap="pre">mkdir -v build
142cd build</userinput></screen>
143
144 <para>Before starting to build GCC, remember to unset any environment
145 variables that override the default optimization flags.</para>
146
147 <para>Now prepare GCC for compilation:</para>
148
149<screen arch="default"><userinput remap="configure">CC=$LFS_TGT-gcc \
150CXX=$LFS_TGT-g++ \
151AR=$LFS_TGT-ar \
152RANLIB=$LFS_TGT-ranlib \
153../configure \
154 --prefix=/tools \
155 --with-local-prefix=/tools \
156 --with-native-system-header-dir=/tools/include \
157 --enable-languages=c,c++ \
158 --disable-libstdcxx-pch \
159 --disable-multilib \
160 --disable-bootstrap \
161 --disable-libgomp</userinput></screen>
162
163<screen arch="ml_32,ml_x32,ml_all"><userinput remap="configure">mlist="m64"</userinput>
164<userinput arch="ml_32,ml_all" remap="configure">mlist="$mlist,m32"</userinput>
165<userinput arch="ml_x32,ml_all" remap="configure">mlist="$mlist,mx32"</userinput>
166<userinput remap="configure">CC=$LFS_TGT-gcc \
167CXX=$LFS_TGT-g++ \
168AR=$LFS_TGT-ar \
169RANLIB=$LFS_TGT-ranlib \
170../configure \
171 --prefix=/tools \
172 --with-local-prefix=/tools \
173 --with-native-system-header-dir=/tools/include \
174 --enable-languages=c,c++ \
175 --disable-libstdcxx-pch \
176 --enable-multilib \
177 --with-multilib-list=$mlist \
178 --with-system-zlib \
179 --disable-bootstrap \
180 --disable-libgomp</userinput></screen>
181
182 <variablelist>
183 <title>The meaning of the new configure options:</title>
184
185 <varlistentry>
186 <term><parameter>--enable-languages=c,c++</parameter></term>
187 <listitem>
188 <para>This option ensures that both the C and C++ compilers are
189 built.</para>
190 </listitem>
191 </varlistentry>
192
193 <varlistentry>
194 <term><parameter>--disable-libstdcxx-pch</parameter></term>
195 <listitem>
196 <para>Do not build the pre-compiled header (PCH) for
197 <filename class="libraryfile">libstdc++</filename>. It takes up a
198 lot of space, and we have no use for it.</para>
199 </listitem>
200 </varlistentry>
201
202 <varlistentry>
203 <term><parameter>--disable-bootstrap</parameter></term>
204 <listitem>
205 <para>For native builds of GCC, the default is to do a "bootstrap"
206 build. This does not just compile GCC, but compiles it several times.
207 It uses the programs compiled in a first round to compile itself a
208 second time, and then again a third time. The second and third
209 iterations are compared to make sure it can reproduce itself
210 flawlessly. This also implies that it was compiled correctly.
211 However, the LFS build method should provide a solid compiler
212 without the need to bootstrap each time.</para>
213 </listitem>
214 </varlistentry>
215
216 </variablelist>
217
218 <para>Compile the package:</para>
219
220<screen><userinput remap="make">make</userinput></screen>
221
222 <para>Install the package:</para>
223
224<screen><userinput remap="install">make install</userinput></screen>
225
226 <para>As a finishing touch, create a symlink. Many programs and scripts
227 run <command>cc</command> instead of <command>gcc</command>, which is
228 used to keep programs generic and therefore usable on all kinds of UNIX
229 systems where the GNU C compiler is not always installed. Running
230 <command>cc</command> leaves the system administrator free to decide
231 which C compiler to install:</para>
232
233<screen><userinput remap="install">ln -sv gcc /tools/bin/cc</userinput></screen>
234
235 <caution>
236 <para>At this point, it is imperative to stop and ensure that the basic
237 functions (compiling and linking) of the new toolchain are working as
238 expected. To perform a sanity check, run the following commands:</para>
239
240<screen><userinput>echo 'int main(){}' &gt; dummy.c
241cc dummy.c
242readelf -l a.out | grep ': /tools'</userinput></screen>
243
244 <para>If everything is working correctly, there should be no errors,
245 and the output of the last command will be of the form:</para>
246
247<screen><computeroutput>[Requesting program interpreter: /tools/lib64/ld-linux-x86-64.so.2]</computeroutput></screen>
248
249
250 <para arch="ml_32,ml_all">Repeat the test for 32-bit:</para>
251
252<screen arch="ml_32,ml_all"><userinput>cc -m32 dummy.c
253readelf -l a.out | grep ': /tools'</userinput></screen>
254
255 <para arch="ml_32,ml_all">In this case, the output shoud be:</para>
256
257<screen arch="ml_32,ml_all"><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</computeroutput></screen>
258
259 <para arch="ml_x32,ml_all">Repeat the test for x32-bit:</para>
260
261<screen arch="ml_x32,ml_all"><userinput>cc -mx32 dummy.c
262readelf -l a.out | grep ': /tools'</userinput></screen>
263
264 <para arch="ml_x32,ml_all">In this case, the output shoud be:</para>
265
266<screen arch="ml_x32,ml_all"><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux-x32.so.2]</computeroutput></screen>
267
268 <para arch="default">Note that the dynamic linker will be
269 /tools/lib/ld-linux.so.2 for 32-bit machines.</para>
270
271 <para>If the output is not shown as above or there was no output at all,
272 then something is wrong. Investigate and retrace the steps to find out
273 where the problem is and correct it. This issue must be resolved before
274 continuing on. First, perform the sanity check again, using
275 <command>gcc</command> instead of <command>cc</command>. If this works,
276 then the <filename class="symlink">/tools/bin/cc</filename> symlink is
277 missing. Install the symlink as per above.
278 Next, ensure that the <envar>PATH</envar> is correct. This
279 can be checked by running <command>echo $PATH</command> and verifying that
280 <filename class="directory">/tools/bin</filename> is at the head of the
281 list. If the <envar>PATH</envar> is wrong it could mean that you are not
282 logged in as user <systemitem class="username">lfs</systemitem> or that
283 something went wrong back in <xref linkend="ch-tools-settingenviron"
284 role="."/></para>
285
286 <para>Once all is well, clean up the test files:</para>
287
288<screen><userinput>rm -v dummy.c a.out</userinput></screen>
289
290 </caution>
291
292 </sect2>
293
294 <sect2 role="content">
295 <title/>
296
297 <para>Details on this package are located in
298 <xref linkend="contents-gcc" role="."/></para>
299
300 </sect2>
301
302</sect1>
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