Mercurial > hg > CbC > CbC_gcc

comparison INSTALL/build.html @ 0:a06113de4d67

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
first commit
author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
parents
children 58ad6c70ea60
comparison
equal deleted inserted replaced
-1:000000000000 0:a06113de4d67
1 <html lang="en">
2 <head>
3 <title>Installing GCC: Building</title>
4 <meta http-equiv="Content-Type" content="text/html">
5 <meta name="description" content="Installing GCC: Building">
6 <meta name="generator" content="makeinfo 4.12">
7 <link title="Top" rel="top" href="#Top">
8 <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
9 <!--
10 Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
11 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
12 2008 Free Software Foundation, Inc.
13
14 Permission is granted to copy, distribute and/or modify this document
15 under the terms of the GNU Free Documentation License, Version 1.2 or
16 any later version published by the Free Software Foundation; with no
17 Invariant Sections, the Front-Cover texts being (a) (see below), and
18 with the Back-Cover Texts being (b) (see below). A copy of the
19 license is included in the section entitled "GNU Free Documentation License".
20
21 (a) The FSF's Front-Cover Text is:
22
23 A GNU Manual
24
25 (b) The FSF's Back-Cover Text is:
26
27 You have freedom to copy and modify this GNU Manual, like GNU
28 software. Copies published by the Free Software Foundation raise
29 funds for GNU development.-->
30 <meta http-equiv="Content-Style-Type" content="text/css">
31 <style type="text/css"><!--
32 pre.display { font-family:inherit }
33 pre.format { font-family:inherit }
34 pre.smalldisplay { font-family:inherit; font-size:smaller }
35 pre.smallformat { font-family:inherit; font-size:smaller }
36 pre.smallexample { font-size:smaller }
37 pre.smalllisp { font-size:smaller }
38 span.sc { font-variant:small-caps }
39 span.roman { font-family:serif; font-weight:normal; }
40 span.sansserif { font-family:sans-serif; font-weight:normal; }
41 --></style>
42 </head>
43 <body>
44 <h1 class="settitle">Installing GCC: Building</h1>
45 <a name="index-Installing-GCC_003a-Building-1"></a>
46 Now that GCC is configured, you are ready to build the compiler and
47 runtime libraries.
48
49 <p>Some commands executed when making the compiler may fail (return a
50 nonzero status) and be ignored by <samp><span class="command">make</span></samp>. These failures, which
51 are often due to files that were not found, are expected, and can safely
52 be ignored.
53
54 <p>It is normal to have compiler warnings when compiling certain files.
55 Unless you are a GCC developer, you can generally ignore these warnings
56 unless they cause compilation to fail. Developers should attempt to fix
57 any warnings encountered, however they can temporarily continue past
58 warnings-as-errors by specifying the configure flag
59 <samp><span class="option">--disable-werror</span></samp>.
60
61 <p>On certain old systems, defining certain environment variables such as
62 <samp><span class="env">CC</span></samp> can interfere with the functioning of <samp><span class="command">make</span></samp>.
63
64 <p>If you encounter seemingly strange errors when trying to build the
65 compiler in a directory other than the source directory, it could be
66 because you have previously configured the compiler in the source
67 directory. Make sure you have done all the necessary preparations.
68
69 <p>If you build GCC on a BSD system using a directory stored in an old System
70 V file system, problems may occur in running <samp><span class="command">fixincludes</span></samp> if the
71 System V file system doesn't support symbolic links. These problems
72 result in a failure to fix the declaration of <code>size_t</code> in
73 <samp><span class="file">sys/types.h</span></samp>. If you find that <code>size_t</code> is a signed type and
74 that type mismatches occur, this could be the cause.
75
76 <p>The solution is not to use such a directory for building GCC.
77
78 <p>Similarly, when building from SVN or snapshots, or if you modify
79 <samp><span class="file">*.l</span></samp> files, you need the Flex lexical analyzer generator
80 installed. If you do not modify <samp><span class="file">*.l</span></samp> files, releases contain
81 the Flex-generated files and you do not need Flex installed to build
82 them. There is still one Flex-based lexical analyzer (part of the
83 build machinery, not of GCC itself) that is used even if you only
84 build the C front end.
85
86 <p>When building from SVN or snapshots, or if you modify Texinfo
87 documentation, you need version 4.7 or later of Texinfo installed if you
88 want Info documentation to be regenerated. Releases contain Info
89 documentation pre-built for the unmodified documentation in the release.
90
91 <h3 class="section"><a name="TOC0"></a>Building a native compiler</h3>
92
93 <p>For a native build, the default configuration is to perform
94 a 3-stage bootstrap of the compiler when &lsquo;<samp><span class="samp">make</span></samp>&rsquo; is invoked.
95 This will build the entire GCC system and ensure that it compiles
96 itself correctly. It can be disabled with the <samp><span class="option">--disable-bootstrap</span></samp>
97 parameter to &lsquo;<samp><span class="samp">configure</span></samp>&rsquo;, but bootstrapping is suggested because
98 the compiler will be tested more completely and could also have
99 better performance.
100
101 <p>The bootstrapping process will complete the following steps:
102
103 <ul>
104 <li>Build tools necessary to build the compiler.
105
106 <li>Perform a 3-stage bootstrap of the compiler. This includes building
107 three times the target tools for use by the compiler such as binutils
108 (bfd, binutils, gas, gprof, ld, and opcodes) if they have been
109 individually linked or moved into the top level GCC source tree before
110 configuring.
111
112 <li>Perform a comparison test of the stage2 and stage3 compilers.
113
114 <li>Build runtime libraries using the stage3 compiler from the previous step.
115
116 </ul>
117
118 <p>If you are short on disk space you might consider &lsquo;<samp><span class="samp">make
119 bootstrap-lean</span></samp>&rsquo; instead. The sequence of compilation is the
120 same described above, but object files from the stage1 and
121 stage2 of the 3-stage bootstrap of the compiler are deleted as
122 soon as they are no longer needed.
123
124 <p>If you wish to use non-default GCC flags when compiling the stage2
125 and stage3 compilers, set <code>BOOT_CFLAGS</code> on the command line when
126 doing &lsquo;<samp><span class="samp">make</span></samp>&rsquo;. For example, if you want to save additional space
127 during the bootstrap and in the final installation as well, you can
128 build the compiler binaries without debugging information as in the
129 following example. This will save roughly 40% of disk space both for
130 the bootstrap and the final installation. (Libraries will still contain
131 debugging information.)
132
133 <pre class="smallexample"> make BOOT_CFLAGS='-O' bootstrap
134 </pre>
135 <p>You can place non-default optimization flags into <code>BOOT_CFLAGS</code>; they
136 are less well tested here than the default of &lsquo;<samp><span class="samp">-g -O2</span></samp>&rsquo;, but should
137 still work. In a few cases, you may find that you need to specify special
138 flags such as <samp><span class="option">-msoft-float</span></samp> here to complete the bootstrap; or,
139 if the native compiler miscompiles the stage1 compiler, you may need
140 to work around this, by choosing <code>BOOT_CFLAGS</code> to avoid the parts
141 of the stage1 compiler that were miscompiled, or by using &lsquo;<samp><span class="samp">make
142 bootstrap4</span></samp>&rsquo; to increase the number of stages of bootstrap.
143
144 <p><code>BOOT_CFLAGS</code> does not apply to bootstrapped target libraries.
145 Since these are always compiled with the compiler currently being
146 bootstrapped, you can use <code>CFLAGS_FOR_TARGET</code> to modify their
147 compilation flags, as for non-bootstrapped target libraries.
148 Again, if the native compiler miscompiles the stage1 compiler, you may
149 need to work around this by avoiding non-working parts of the stage1
150 compiler. Use <code>STAGE1_LIBCFLAGS</code> to this end.
151
152 <p>If you used the flag <samp><span class="option">--enable-languages=...</span></samp> to restrict
153 the compilers to be built, only those you've actually enabled will be
154 built. This will of course only build those runtime libraries, for
155 which the particular compiler has been built. Please note,
156 that re-defining <samp><span class="env">LANGUAGES</span></samp> when calling &lsquo;<samp><span class="samp">make</span></samp>&rsquo;
157 <strong>does not</strong> work anymore!
158
159 <p>If the comparison of stage2 and stage3 fails, this normally indicates
160 that the stage2 compiler has compiled GCC incorrectly, and is therefore
161 a potentially serious bug which you should investigate and report. (On
162 a few systems, meaningful comparison of object files is impossible; they
163 always appear &ldquo;different&rdquo;. If you encounter this problem, you will
164 need to disable comparison in the <samp><span class="file">Makefile</span></samp>.)
165
166 <p>If you do not want to bootstrap your compiler, you can configure with
167 <samp><span class="option">--disable-bootstrap</span></samp>. In particular cases, you may want to
168 bootstrap your compiler even if the target system is not the same as
169 the one you are building on: for example, you could build a
170 <code>powerpc-unknown-linux-gnu</code> toolchain on a
171 <code>powerpc64-unknown-linux-gnu</code> host. In this case, pass
172 <samp><span class="option">--enable-bootstrap</span></samp> to the configure script.
173
174 <h3 class="section"><a name="TOC1"></a>Building a cross compiler</h3>
175
176 <p>When building a cross compiler, it is not generally possible to do a
177 3-stage bootstrap of the compiler. This makes for an interesting problem
178 as parts of GCC can only be built with GCC.
179
180 <p>To build a cross compiler, we first recommend building and installing a
181 native compiler. You can then use the native GCC compiler to build the
182 cross compiler. The installed native compiler needs to be GCC version
183 2.95 or later.
184
185 <p>If the cross compiler is to be built with support for the Java
186 programming language and the ability to compile .java source files is
187 desired, the installed native compiler used to build the cross
188 compiler needs to be the same GCC version as the cross compiler. In
189 addition the cross compiler needs to be configured with
190 <samp><span class="option">--with-ecj-jar=...</span></samp>.
191
192 <p>Assuming you have already installed a native copy of GCC and configured
193 your cross compiler, issue the command <samp><span class="command">make</span></samp>, which performs the
194 following steps:
195
196 <ul>
197 <li>Build host tools necessary to build the compiler.
198
199 <li>Build target tools for use by the compiler such as binutils (bfd,
200 binutils, gas, gprof, ld, and opcodes)
201 if they have been individually linked or moved into the top level GCC source
202 tree before configuring.
203
204 <li>Build the compiler (single stage only).
205
206 <li>Build runtime libraries using the compiler from the previous step.
207 </ul>
208
209 <p>Note that if an error occurs in any step the make process will exit.
210
211 <p>If you are not building GNU binutils in the same source tree as GCC,
212 you will need a cross-assembler and cross-linker installed before
213 configuring GCC. Put them in the directory
214 <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/bin</span></samp>. Here is a table of the tools
215 you should put in this directory:
216
217 <dl>
218 <dt><samp><span class="file">as</span></samp><dd>This should be the cross-assembler.
219
220 <br><dt><samp><span class="file">ld</span></samp><dd>This should be the cross-linker.
221
222 <br><dt><samp><span class="file">ar</span></samp><dd>This should be the cross-archiver: a program which can manipulate
223 archive files (linker libraries) in the target machine's format.
224
225 <br><dt><samp><span class="file">ranlib</span></samp><dd>This should be a program to construct a symbol table in an archive file.
226 </dl>
227
228 <p>The installation of GCC will find these programs in that directory,
229 and copy or link them to the proper place to for the cross-compiler to
230 find them when run later.
231
232 <p>The easiest way to provide these files is to build the Binutils package.
233 Configure it with the same <samp><span class="option">--host</span></samp> and <samp><span class="option">--target</span></samp>
234 options that you use for configuring GCC, then build and install
235 them. They install their executables automatically into the proper
236 directory. Alas, they do not support all the targets that GCC
237 supports.
238
239 <p>If you are not building a C library in the same source tree as GCC,
240 you should also provide the target libraries and headers before
241 configuring GCC, specifying the directories with
242 <samp><span class="option">--with-sysroot</span></samp> or <samp><span class="option">--with-headers</span></samp> and
243 <samp><span class="option">--with-libs</span></samp>. Many targets also require &ldquo;start files&rdquo; such
244 as <samp><span class="file">crt0.o</span></samp> and
245 <samp><span class="file">crtn.o</span></samp> which are linked into each executable. There may be several
246 alternatives for <samp><span class="file">crt0.o</span></samp>, for use with profiling or other
247 compilation options. Check your target's definition of
248 <code>STARTFILE_SPEC</code> to find out what start files it uses.
249
250 <h3 class="section"><a name="TOC2"></a>Building in parallel</h3>
251
252 <p>GNU Make 3.79 and above, which is necessary to build GCC, support
253 building in parallel. To activate this, you can use &lsquo;<samp><span class="samp">make -j 2</span></samp>&rsquo;
254 instead of &lsquo;<samp><span class="samp">make</span></samp>&rsquo;. You can also specify a bigger number, and
255 in most cases using a value greater than the number of processors in
256 your machine will result in fewer and shorter I/O latency hits, thus
257 improving overall throughput; this is especially true for slow drives
258 and network filesystems.
259
260 <h3 class="section"><a name="TOC3"></a>Building the Ada compiler</h3>
261
262 <p>In order to build GNAT, the Ada compiler, you need a working GNAT
263 compiler (GCC version 3.4 or later).
264 This includes GNAT tools such as <samp><span class="command">gnatmake</span></samp> and
265 <samp><span class="command">gnatlink</span></samp>, since the Ada front end is written in Ada and
266 uses some GNAT-specific extensions.
267
268 <p>In order to build a cross compiler, it is suggested to install
269 the new compiler as native first, and then use it to build the cross
270 compiler.
271
272 <p><samp><span class="command">configure</span></samp> does not test whether the GNAT installation works
273 and has a sufficiently recent version; if too old a GNAT version is
274 installed, the build will fail unless <samp><span class="option">--enable-languages</span></samp> is
275 used to disable building the Ada front end.
276
277 <p><samp><span class="env">ADA_INCLUDE_PATH</span></samp> and <samp><span class="env">ADA_OBJECT_PATH</span></samp> environment variables
278 must not be set when building the Ada compiler, the Ada tools, or the
279 Ada runtime libraries. You can check that your build environment is clean
280 by verifying that &lsquo;<samp><span class="samp">gnatls -v</span></samp>&rsquo; lists only one explicit path in each
281 section.
282
283 <h3 class="section"><a name="TOC4"></a>Building with profile feedback</h3>
284
285 <p>It is possible to use profile feedback to optimize the compiler itself. This
286 should result in a faster compiler binary. Experiments done on x86 using gcc
287 3.3 showed approximately 7 percent speedup on compiling C programs. To
288 bootstrap the compiler with profile feedback, use <code>make profiledbootstrap</code>.
289
290 <p>When &lsquo;<samp><span class="samp">make profiledbootstrap</span></samp>&rsquo; is run, it will first build a <code>stage1</code>
291 compiler. This compiler is used to build a <code>stageprofile</code> compiler
292 instrumented to collect execution counts of instruction and branch
293 probabilities. Then runtime libraries are compiled with profile collected.
294 Finally a <code>stagefeedback</code> compiler is built using the information collected.
295
296 <p>Unlike standard bootstrap, several additional restrictions apply. The
297 compiler used to build <code>stage1</code> needs to support a 64-bit integral type.
298 It is recommended to only use GCC for this. Also parallel make is currently
299 not supported since collisions in profile collecting may occur.
300
301 <p><hr />
302 <p><a href="./index.html">Return to the GCC Installation page</a>
303
304 <!-- ***Testing***************************************************************** -->
305 <!-- ***Final install*********************************************************** -->
306 <!-- ***Binaries**************************************************************** -->
307 <!-- ***Specific**************************************************************** -->
308 <!-- ***Old documentation****************************************************** -->
309 <!-- ***GFDL******************************************************************** -->
310 <!-- *************************************************************************** -->
311 <!-- Part 6 The End of the Document -->
312 </body></html>
313