source: chapter05/gcc-pass2.xml@ 60970f9

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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 arch="default"><userinput remap="configure">CC=$LFS_TGT-gcc \
143CXX=$LFS_TGT-g++ \
144AR=$LFS_TGT-ar \
145RANLIB=$LFS_TGT-ranlib \
146../configure \
147 --prefix=/tools \
148 --with-local-prefix=/tools \
149 --with-native-system-header-dir=/tools/include \
150 --enable-languages=c,c++ \
151 --disable-libstdcxx-pch \
152 --disable-multilib \
153 --disable-bootstrap \
154 --disable-libgomp</userinput></screen>
155
156<screen arch="ml_32,ml_x32,ml_all"><userinput remap="configure">mlist="m64"</userinput>
157<userinput arch="ml_32,ml_all" remap="configure">mlist="$mlist,m32"</userinput>
158<userinput arch="ml_x32,ml_all" remap="configure">mlist="$mlist,mx32"</userinput>
159<userinput remap="configure">CC=$LFS_TGT-gcc \
160CXX=$LFS_TGT-g++ \
161AR=$LFS_TGT-ar \
162RANLIB=$LFS_TGT-ranlib \
163../configure \
164 --prefix=/tools \
165 --with-local-prefix=/tools \
166 --with-native-system-header-dir=/tools/include \
167 --enable-languages=c,c++ \
168 --disable-libstdcxx-pch \
169 --enable-multilib \
170 --with-multilib-list=$mlist \
171 --with-system-zlib \
172 --disable-bootstrap \
173 --disable-libgomp</userinput></screen>
174
175 <variablelist>
176 <title>The meaning of the new configure options:</title>
177
178 <varlistentry>
179 <term><parameter>--enable-languages=c,c++</parameter></term>
180 <listitem>
181 <para>This option ensures that both the C and C++ compilers are
182 built.</para>
183 </listitem>
184 </varlistentry>
185
186 <varlistentry>
187 <term><parameter>--disable-libstdcxx-pch</parameter></term>
188 <listitem>
189 <para>Do not build the pre-compiled header (PCH) for
190 <filename class="libraryfile">libstdc++</filename>. It takes up a
191 lot of space, and we have no use for it.</para>
192 </listitem>
193 </varlistentry>
194
195 <varlistentry>
196 <term><parameter>--disable-bootstrap</parameter></term>
197 <listitem>
198 <para>For native builds of GCC, the default is to do a "bootstrap"
199 build. This does not just compile GCC, but compiles it several times.
200 It uses the programs compiled in a first round to compile itself a
201 second time, and then again a third time. The second and third
202 iterations are compared to make sure it can reproduce itself
203 flawlessly. This also implies that it was compiled correctly.
204 However, the LFS build method should provide a solid compiler
205 without the need to bootstrap each time.</para>
206 </listitem>
207 </varlistentry>
208
209 </variablelist>
210
211 <para>Compile the package:</para>
212
213<screen><userinput remap="make">make</userinput></screen>
214
215 <para>Install the package:</para>
216
217<screen><userinput remap="install">make install</userinput></screen>
218
219 <para>As a finishing touch, create a symlink. Many programs and scripts
220 run <command>cc</command> instead of <command>gcc</command>, which is
221 used to keep programs generic and therefore usable on all kinds of UNIX
222 systems where the GNU C compiler is not always installed. Running
223 <command>cc</command> leaves the system administrator free to decide
224 which C compiler to install:</para>
225
226<screen><userinput remap="install">ln -sv gcc /tools/bin/cc</userinput></screen>
227
228 <caution>
229 <para>At this point, it is imperative to stop and ensure that the basic
230 functions (compiling and linking) of the new toolchain are working as
231 expected. To perform a sanity check, run the following commands:</para>
232
233<screen><userinput>echo 'int main(){}' &gt; dummy.c
234cc dummy.c
235readelf -l a.out | grep ': /tools'</userinput></screen>
236
237 <para>If everything is working correctly, there should be no errors,
238 and the output of the last command will be of the form:</para>
239
240<screen><computeroutput>[Requesting program interpreter: /tools/lib64/ld-linux-x86-64.so.2]</computeroutput></screen>
241
242
243 <para arch="ml_32,ml_all">Repeat the test for 32-bit:</para>
244
245<screen arch="ml_32,ml_all"><userinput>cc -m32 dummy.c
246readelf -l a.out | grep ': /tools'</userinput></screen>
247
248 <para arch="ml_32,ml_all">In this case, the output shoud be:</para>
249
250<screen arch="ml_32,ml_all"><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</computeroutput></screen>
251
252 <para arch="ml_x32,ml_all">Repeat the test for x32-bit:</para>
253
254<screen arch="ml_x32,ml_all"><userinput>cc -mx32 dummy.c
255readelf -l a.out | grep ': /tools'</userinput></screen>
256
257 <para arch="ml_x32,ml_all">In this case, the output shoud be:</para>
258
259<screen arch="ml_x32,ml_all"><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux-x32.so.2]</computeroutput></screen>
260
261 <para arch="default">Note that the dynamic linker will be
262 /tools/lib/ld-linux.so.2 for 32-bit machines.</para>
263
264 <para>If the output is not shown as above or there was no output at all,
265 then something is wrong. Investigate and retrace the steps to find out
266 where the problem is and correct it. This issue must be resolved before
267 continuing on. First, perform the sanity check again, using
268 <command>gcc</command> instead of <command>cc</command>. If this works,
269 then the <filename class="symlink">/tools/bin/cc</filename> symlink is
270 missing. Install the symlink as per above.
271 Next, ensure that the <envar>PATH</envar> is correct. This
272 can be checked by running <command>echo $PATH</command> and verifying that
273 <filename class="directory">/tools/bin</filename> is at the head of the
274 list. If the <envar>PATH</envar> is wrong it could mean that you are not
275 logged in as user <systemitem class="username">lfs</systemitem> or that
276 something went wrong back in <xref linkend="ch-tools-settingenviron"
277 role="."/></para>
278
279 <para>Once all is well, clean up the test files:</para>
280
281<screen><userinput>rm -v dummy.c a.out</userinput></screen>
282
283 </caution>
284
285 </sect2>
286
287 <sect2 role="content">
288 <title/>
289
290 <para>Details on this package are located in
291 <xref linkend="contents-gcc" role="."/></para>
292
293 </sect2>
294
295</sect1>
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