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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 17bcde9f9b18e1076a9f20d1dcd3b4a8e9985352 / . / docs / GCCFEBuildInstrs.html
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7 <title>Building the LLVM GCC Front-End</title>
8</head>
9<body>
10
11<div class="doc_title">
12 Building the LLVM GCC Front-End
13</div>
14
15<ol>
16 <li><a href="#instructions">Building llvm-gcc from Source</a></li>
17 <li><a href="#license">License Information</a></li>
18</ol>
19
20<div class="doc_author">
21 <p>Written by the LLVM Team</p>
22</div>
23
24<!-- *********************************************************************** -->
25<div class="doc_section">
26 <a name="instructions">Building llvm-gcc from Source</a>
27</div>
28<!-- *********************************************************************** -->
29
30<div class="doc_text">
31
32<p>This section describes how to acquire and build llvm-gcc 4.0 and 4.2, which are
33based on the GCC 4.0.1/4.2.1 front-ends respectively. Both front-ends support C,
34C++, Objective-C and Objective-C++. The 4.2 front-end also supports Ada and
35Fortran to some extent. Note that the instructions for building these front-ends
36are completely different (and much easier!) than those for building llvm-gcc3 in
37the past.</p>
38
39<ol>
40 <li><p>Retrieve the appropriate llvm-gcc4.x-y.z.source.tar.gz archive from the
41 <a href="http://llvm.org/releases/">llvm web site</a>.</p>
42
43 <p>It is also possible to download the sources of the llvm-gcc front end
44 from a read-only mirror using subversion. To check out the 4.0 code
45 for first time use:</p>
46
47<div class="doc_code">
48<pre>
49svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.0/trunk <i>dst-directory</i>
50</pre>
51</div>
52
53<p>To check out the 4.2 code use:</p>
54
55<div class="doc_code">
56<pre>
57svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.2/trunk <i>dst-directory</i>
58</pre>
59</div>
60
61 <p>After that, the code can be be updated in the destination directory
62 using:</p>
63
64<div class="doc_code">
65<pre>svn update</pre>
66</div>
67
68 <p>The mirror is brought up to date every evening.</p></li>
69
70 <li>Follow the directions in the top-level <tt>README.LLVM</tt> file for
71 up-to-date instructions on how to build llvm-gcc. See below for building
72 with support for Ada or Fortran.
73</ol>
74
75</div>
76
77<!-- *********************************************************************** -->
78<div class="doc_section">
79 <a name="license">Building the Ada front-end</a>
80</div>
81
82<div class="doc_text">
83<p>Building with support for Ada amounts to following the directions in the
84top-level <tt>README.LLVM</tt> file, adding ",ada" to EXTRALANGS, for example:
85<tt>EXTRALANGS=,ada</tt></p>
86
87<p>There are some complications however:</p>
88
89<ol>
90 <li><p>The only platform for which the Ada front-end is known to build is
91 32 bit intel x86 running linux. It is unlikely to build for other
92 systems without some work.</p></li>
93 <li><p>The build requires having a compiler that supports Ada, C and C++.
94 The Ada front-end is written in Ada so an Ada compiler is needed to
Duncan Sands17bcde92008-02-16 09:47:41 +0000[diff] [blame^]95 build it. Appropriate Ada compilers are gcc-4.2 (or earlier) or the
96 <a href="http://libre.adacore.com/">2006 GNAT GPL Edition</a>
97 (or earlier). As a general rule, the Ada compiler used for the
98 build must not be more recent than the Ada compiler it is building.
99 This is why the build fails with gcc-4.3 and the 2007 GNAT GPL Edition.
100 The LLVM parts of llvm-gcc are written in C++ so a C++ compiler is
101 needed to build them. The rest of gcc is written in C.
Duncan Sands8655b152008-02-14 17:53:22 +0000[diff] [blame]102 Some linux distributions provide a version of gcc that supports all
103 three languages (the Ada part often comes as an add-on package to
104 the rest of gcc). Otherwise it is possible to combine two versions
105 of gcc, one that supports Ada and C (such as the
106 <a href="http://libre.adacore.com/">2006 GNAT GPL Edition</a>)
107 and another which supports C++, see below.</p></li>
108 <li><p>Because the Ada front-end is experimental, it is wise to build the
109 compiler with checking enabled. This causes it to run slower, but
110 helps catch mistakes in the compiler (please report any problems using
111 <a href="http://llvm.org/bugs">LLVM bugzilla</a>).</p></li>
112</ol>
113
114<p>Supposing appropriate compilers are available, llvm-gcc with Ada support can
115 be built on an x86-32 linux box using the following recipe:</p>
116
117<ol>
118 <li><p>Download the <a href="http://llvm.org/releases/download.html">LLVM source</a>
119 and unpack it:</p>
120
121<div class="doc_code">
122<pre>wget http://llvm.org/releases/2.2/llvm-2.2.tar.gz
123tar xzf llvm-2.2.tar.gz
124mv llvm-2.2 llvm</pre>
125</div>
126
127 <p>or <a href="GettingStarted.html#checkout">check out the
128 latest version from subversion</a>:</p>
129
130<div class="doc_code">
131<pre>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</pre>
132</div>
133 </li>
134
135 <li><p>Download the
136 <a href="http://llvm.org/releases/download.html">llvm-gcc-4.2 source</a>
137 and unpack it:</p>
138
139<div class="doc_code">
140<pre>wget http://llvm.org/releases/2.2/llvm-gcc4.2-2.2.source.tar.gz
141tar xzf llvm-gcc4.2-2.2.source.tar.gz
142mv llvm-gcc4.2-2.2.source llvm-gcc-4.2</pre>
143</div>
144
145 <p>or <a href="GettingStarted.html#checkout">check out the
146 latest version from subversion</a>:</p>
147
148<div class="doc_code">
149<pre>svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.2/trunk llvm-gcc-4.2</pre>
150</div>
151 </li>
152
153 <li><p>Make a build directory <tt>llvm-objects</tt> for llvm and make it the
154 current directory:</p>
155
156<div class="doc_code">
157<pre>mkdir llvm-objects
158cd llvm-objects</pre>
159</div>
160 </li>
161
162 <li><p>Configure LLVM (here it is configured to install into <tt>/usr/local</tt>):</p>
163
164<div class="doc_code">
165<pre>../llvm/configure --prefix=<b>/usr/local</b></pre>
166</div>
167
168 <p>If you have a multi-compiler setup and the C++ compiler is not the
169 default, then you can configure like this:</p>
170
171<div class="doc_code">
172<pre>CXX=<b>PATH_TO_C++_COMPILER</b> ../llvm/configure --prefix=<b>/usr/local</b></pre>
173</div>
174 </li>
175
176 <li><p>Build LLVM with checking enabled (use <tt>ENABLE_OPTIMIZED=1</tt> to
177 build without checking):</p>
178
179<div class="doc_code">
180<pre>make ENABLE_OPTIMIZED=0</pre>
181</div>
182 </li>
183
184 <li><p>Install LLVM (optional):</p>
185
186<div class="doc_code">
187<pre>make install</pre>
188</div>
189 </li>
190
191 <li><p>Make a build directory <tt>llvm-gcc-4.2-objects</tt> for llvm-gcc and make it the
192 current directory:</p>
193
194<div class="doc_code">
195<pre>
196cd ..
197mkdir llvm-gcc-4.2-objects
198cd llvm-gcc-4.2-objects</pre>
199</div>
200 </li>
201
202 <li><p>Configure llvm-gcc (here it is configured to install into <tt>/usr/local</tt>).
203 The <tt>--enable-checking</tt> flag turns on sanity checks inside the compiler.
204 If you omit it then LLVM must be built with <tt>make ENABLE_OPTIMIZED=1</tt>.
205 Additional languages can be appended to the --enable-languages switch,
206 for example <tt>--enable-languages=ada,c,c++</tt>.</p>
207
208<div class="doc_code">
209<pre>../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
210</div>
211
212 <p>If you have a multi-compiler setup, then you can configure like this:</p>
213<div class="doc_code">
214
215<pre>
216export CC=<b>PATH_TO_C_AND_ADA_COMPILER</b>
217export CXX=<b>PATH_TO_C++_COMPILER</b>
218../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
219</div>
220 </li>
221
222 <li><p>Build and install the compiler:</p>
223
224<div class="doc_code">
225<pre>make
226make install</pre>
227</div>
228 </li>
229</ol>
230
231</div>
232
233<!-- *********************************************************************** -->
234<div class="doc_section">
235 <a name="license">Building the Fortran front-end</a>
236</div>
237
238<div class="doc_text">
239<p>
240To build with support for Fortran, follow the directions in the top-level
241<tt>README.LLVM</tt> file, adding ",fortran" to EXTRALANGS, for example:</p>
242
243<div class="doc_code">
244<pre>
245EXTRALANGS=,fortran
246</pre>
247</div>
248
249</div>
250
251<!-- *********************************************************************** -->
252<div class="doc_section">
253 <a name="license">License Information</a>
254</div>
255
256<div class="doc_text">
257<p>
258The LLVM GCC frontend is licensed to you under the GNU General Public License
259and the GNU Lesser General Public License. Please see the files COPYING and
260COPYING.LIB for more details.
261</p>
262
263<p>
264More information is <a href="FAQ.html#license">available in the FAQ</a>.
265</p>
266</div>
267
268<!-- *********************************************************************** -->
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