forked from OSchip/llvm-project
parent
db5f7d7699
commit
2dc30a5ac8
|
@ -1,216 +1,216 @@
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|||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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||||
"http://www.w3.org/TR/html4/strict.dtd">
|
||||
<html>
|
||||
<head>
|
||||
<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
|
||||
<title>Clang - Getting Started</title>
|
||||
<link type="text/css" rel="stylesheet" href="menu.css" />
|
||||
<link type="text/css" rel="stylesheet" href="content.css" />
|
||||
</head>
|
||||
<body>
|
||||
|
||||
<!--#include virtual="menu.html.incl"-->
|
||||
|
||||
<div id="content">
|
||||
|
||||
<h1>Getting Started: Building and Running Clang</h1>
|
||||
|
||||
|
||||
<p>This page gives you the shortest path to checking out clang and demos a few
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||||
options. This should get you up and running with the minimum of muss and fuss.
|
||||
If you like what you see, please consider <a href="get_involved.html">getting
|
||||
involved</a> with the clang community.</p>
|
||||
|
||||
|
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<h2>A word of warning</h2>
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|
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<p>While this work aims to provide a fully functional C/C++/ObjC front-end, it
|
||||
is <em>still very early work</em> and is under heavy development. In particular,
|
||||
there is no real C++ support yet (this is obviously a big project), and C/ObjC
|
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support is still missing some features. Some of the more notable missing pieces
|
||||
of C support are:</p>
|
||||
|
||||
<ol>
|
||||
<li>The semantic analyzer does not produce all of the warnings and errors it
|
||||
should.</li>
|
||||
<li>The LLVM code generator is still missing important features. clang is not
|
||||
ready to be used as a general purpose C code generator yet, but if you
|
||||
hit problems and report them to cfe-dev, we'll fix them :).</li>
|
||||
<li>We don't consider the API to be stable yet, and reserve the right to
|
||||
change fundamental things.</li>
|
||||
</ol>
|
||||
|
||||
<p>Our plan is to continue chipping away at these issues until C works really
|
||||
well, but we'd love help from other interested contributors. We expect C to be
|
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in good shape by mid to late 2008.</p>
|
||||
|
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<h3><a name="build">Building clang / working with the code</a></h3>
|
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|
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<p>If you would like to check out and build the project, the current scheme
|
||||
is:</p>
|
||||
|
||||
<ol>
|
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<li><a href="http://www.llvm.org/docs/GettingStarted.html#checkout">Checkout
|
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and build LLVM</a> from SVN head:</li>
|
||||
|
||||
<ul>
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<li><tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
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<li><tt>cd llvm</tt></li>
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||||
<li><tt>./configure; make</tt></li>
|
||||
</ul>
|
||||
<li>Checkout clang:</li>
|
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<ul>
|
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<li>From within the <tt>llvm</tt> directory (where you
|
||||
built llvm):</li>
|
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<li><tt>cd llvm/tools</tt>
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<li><tt>svn co http://llvm.org/svn/llvm-project/cfe/trunk clang</tt></li>
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|
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</ul>
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<li>Non-mac users: Paths to system header files are currently hard coded
|
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into clang; as a result, if clang can't find your system headers,
|
||||
please follow these instructions:</li>
|
||||
|
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<ul>
|
||||
<li>'<tt>touch empty.c; gcc -v empty.c -fsyntax-only</tt>' to get the
|
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path.</li>
|
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<li>Look for the comment "FIXME: temporary hack:
|
||||
hard-coded paths" in <tt>clang/Driver/clang.cpp</tt> and
|
||||
change the lines below to include that path.</li>
|
||||
</ul>
|
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|
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<li>Build clang:</li>
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<ul>
|
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<li><tt>cd clang</tt> (assuming that you are in <tt>llvm/tools</tt>)</li>
|
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<li><tt>make</tt> (this will give you a debug build)</li>
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</ul>
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|
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<li>Try it out (assuming you add llvm/Debug/bin to your path):</li>
|
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<ul>
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<li><tt>clang --help</tt></li>
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<li><tt>clang file.c -fsyntax-only</tt> (check for correctness)</li>
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<li><tt>clang file.c -ast-dump</tt> (internal debug dump of ast)</li>
|
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<li><tt>clang file.c -ast-view</tt> (<a
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href="http://llvm.org/docs/ProgrammersManual.html#ViewGraph">set up graphviz
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and rebuild llvm first</a>)</li>
|
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<li><tt>clang file.c -emit-llvm</tt> (print out unoptimized llvm code)</li>
|
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<li><tt>clang file.c -emit-llvm | llvm-as | opt -std-compile-opts |
|
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llvm-dis</tt> (print out optimized llvm code)</li>
|
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<li><tt>clang file.c -emit-llvm | llvm-as | opt -std-compile-opts | llc
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> file.s</tt> (output native machine code)</li>
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</ul>
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</ol>
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|
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<p>Note that the C front-end uses LLVM, but does not depend on
|
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llvm-gcc. If you encounter problems with building clang, make
|
||||
sure you have the latest SVN version of LLVM. LLVM contains
|
||||
support libraries for clang that will be updated as well as
|
||||
development on clang progresses.</p>
|
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|
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<h3>Examples of using clang</h3>
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||||
|
||||
<p>The clang driver takes a lot of GCC compatible options, which you can see
|
||||
with 'clang --help'. Here are a few examples:</p>
|
||||
<!-- Thanks to
|
||||
http://shiflett.org/blog/2006/oct/formatting-and-highlighting-php-code-listings
|
||||
Site suggested using pre in CSS, but doesn't work in IE, so went for the <pre>
|
||||
tag. -->
|
||||
|
||||
<pre class="code">
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||||
$ <b>cat ~/t.c</b>
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typedef float V __attribute__((vector_size(16)));
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V foo(V a, V b) { return a+b*a; }
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</pre>
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<h4>Preprocessing:</h4>
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<pre class="code">
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$ <b>clang ~/t.c -E</b>
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# 1 "/Users/sabre/t.c" 1
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typedef float V __attribute__((vector_size(16)));
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V foo(V a, V b) { return a+b*a; }
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</pre>
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<h4>Type checking:</h4>
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<pre class="code">
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$ <b>clang -fsyntax-only ~/t.c</b>
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</pre>
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<h4>GCC options:</h4>
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<pre class="code">
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$ <b>clang -fsyntax-only ~/t.c -pedantic</b>
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/Users/sabre/t.c:2:17: warning: extension used
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typedef float V __attribute__((vector_size(16)));
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^
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1 diagnostic generated.
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</pre>
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<h4>Pretty printing from the AST:</h4>
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<pre class="code">
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$ <b>clang ~/t.c -ast-print</b>
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typedef float V __attribute__(( vector_size(16) ));
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V foo(V a, V b) {
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return a + b * a;
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}
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</pre>
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|
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<h4>Code generation with LLVM:</h4>
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<pre class="code">
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$ <b>clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llvm-dis</b>
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define <4 x float> @foo(<4 x float> %a, <4 x float> %b) {
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entry:
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%mul = mul <4 x float> %b, %a
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%add = add <4 x float> %mul, %a
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ret <4 x float> %add
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}
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$ <b>clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=ppc32 -mcpu=g5</b>
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..
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_foo:
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vmaddfp v2, v3, v2, v2
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blr
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$ <b>clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=x86 -mcpu=yonah</b>
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..
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_foo:
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mulps %xmm0, %xmm1
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addps %xmm0, %xmm1
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movaps %xmm1, %xmm0
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ret
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</pre>
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|
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<h3>GCC "Emulation" Driver</h3>
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|
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While the <tt>clang</tt> executable is a compiler driver that can perform code
|
||||
generation, program analysis, and other actions, it is not designed to be a
|
||||
drop-in replacement for GCC's <tt>cc</tt>. There is interest in developing such
|
||||
a driver for clang, but in the interim the clang source tree includes a Python
|
||||
script <tt>ccc</tt> in the <tt>utils</tt> subdirectory that provides some of
|
||||
this functionality (the script is intended to be used where GCC's <tt>cc</tt>
|
||||
could be used). It is currently a work in progress, and eventually will likely
|
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be replaced by a more complete driver.
|
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|
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<p>Example use:</p>
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|
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<pre class="code">
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$ <b>ccc t.c</b>
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clang -emit-llvm-bc -o t.o -U__GNUC__ t.c
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llvm-ld -native -o a.out t.o
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$ <b>ls</b>
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a.out a.out.bc t.c t.o
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</pre>
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</div>
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</body>
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||||
</html>
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
|
||||
"http://www.w3.org/TR/html4/strict.dtd">
|
||||
<html>
|
||||
<head>
|
||||
<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
|
||||
<title>Clang - Getting Started</title>
|
||||
<link type="text/css" rel="stylesheet" href="menu.css" />
|
||||
<link type="text/css" rel="stylesheet" href="content.css" />
|
||||
</head>
|
||||
<body>
|
||||
|
||||
<!--#include virtual="menu.html.incl"-->
|
||||
|
||||
<div id="content">
|
||||
|
||||
<h1>Getting Started: Building and Running Clang</h1>
|
||||
|
||||
|
||||
<p>This page gives you the shortest path to checking out clang and demos a few
|
||||
options. This should get you up and running with the minimum of muss and fuss.
|
||||
If you like what you see, please consider <a href="get_involved.html">getting
|
||||
involved</a> with the clang community.</p>
|
||||
|
||||
|
||||
<h2>A word of warning</h2>
|
||||
|
||||
<p>While this work aims to provide a fully functional C/C++/ObjC front-end, it
|
||||
is <em>still very early work</em> and is under heavy development. In particular,
|
||||
there is no real C++ support yet (this is obviously a big project), and C/ObjC
|
||||
support is still missing some features. Some of the more notable missing pieces
|
||||
of C support are:</p>
|
||||
|
||||
<ol>
|
||||
<li>The semantic analyzer does not produce all of the warnings and errors it
|
||||
should.</li>
|
||||
<li>The LLVM code generator is still missing important features. clang is not
|
||||
ready to be used as a general purpose C code generator yet, but if you
|
||||
hit problems and report them to cfe-dev, we'll fix them :).</li>
|
||||
<li>We don't consider the API to be stable yet, and reserve the right to
|
||||
change fundamental things.</li>
|
||||
</ol>
|
||||
|
||||
<p>Our plan is to continue chipping away at these issues until C works really
|
||||
well, but we'd love help from other interested contributors. We expect C to be
|
||||
in good shape by mid to late 2008.</p>
|
||||
|
||||
<h3><a name="build">Building clang / working with the code</a></h3>
|
||||
|
||||
<p>If you would like to check out and build the project, the current scheme
|
||||
is:</p>
|
||||
|
||||
<ol>
|
||||
<li><a href="http://www.llvm.org/docs/GettingStarted.html#checkout">Checkout
|
||||
and build LLVM</a> from SVN head:</li>
|
||||
|
||||
<ul>
|
||||
<li><tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
|
||||
<li><tt>cd llvm</tt></li>
|
||||
<li><tt>./configure; make</tt></li>
|
||||
</ul>
|
||||
<li>Checkout clang:</li>
|
||||
<ul>
|
||||
<li>From within the <tt>llvm</tt> directory (where you
|
||||
built llvm):</li>
|
||||
<li><tt>cd llvm/tools</tt>
|
||||
<li><tt>svn co http://llvm.org/svn/llvm-project/cfe/trunk clang</tt></li>
|
||||
|
||||
</ul>
|
||||
<li>Non-mac users: Paths to system header files are currently hard coded
|
||||
into clang; as a result, if clang can't find your system headers,
|
||||
please follow these instructions:</li>
|
||||
|
||||
<ul>
|
||||
<li>'<tt>touch empty.c; gcc -v empty.c -fsyntax-only</tt>' to get the
|
||||
path.</li>
|
||||
<li>Look for the comment "FIXME: temporary hack:
|
||||
hard-coded paths" in <tt>clang/Driver/clang.cpp</tt> and
|
||||
change the lines below to include that path.</li>
|
||||
</ul>
|
||||
|
||||
<li>Build clang:</li>
|
||||
<ul>
|
||||
<li><tt>cd clang</tt> (assuming that you are in <tt>llvm/tools</tt>)</li>
|
||||
<li><tt>make</tt> (this will give you a debug build)</li>
|
||||
</ul>
|
||||
|
||||
<li>Try it out (assuming you add llvm/Debug/bin to your path):</li>
|
||||
<ul>
|
||||
<li><tt>clang --help</tt></li>
|
||||
<li><tt>clang file.c -fsyntax-only</tt> (check for correctness)</li>
|
||||
<li><tt>clang file.c -ast-dump</tt> (internal debug dump of ast)</li>
|
||||
<li><tt>clang file.c -ast-view</tt> (<a
|
||||
href="http://llvm.org/docs/ProgrammersManual.html#ViewGraph">set up graphviz
|
||||
and rebuild llvm first</a>)</li>
|
||||
<li><tt>clang file.c -emit-llvm</tt> (print out unoptimized llvm code)</li>
|
||||
<li><tt>clang file.c -emit-llvm | llvm-as | opt -std-compile-opts |
|
||||
llvm-dis</tt> (print out optimized llvm code)</li>
|
||||
<li><tt>clang file.c -emit-llvm | llvm-as | opt -std-compile-opts | llc
|
||||
> file.s</tt> (output native machine code)</li>
|
||||
</ul>
|
||||
</ol>
|
||||
|
||||
<p>Note that the C front-end uses LLVM, but does not depend on
|
||||
llvm-gcc. If you encounter problems with building clang, make
|
||||
sure you have the latest SVN version of LLVM. LLVM contains
|
||||
support libraries for clang that will be updated as well as
|
||||
development on clang progresses.</p>
|
||||
|
||||
<h3>Examples of using clang</h3>
|
||||
|
||||
<p>The clang driver takes a lot of GCC compatible options, which you can see
|
||||
with 'clang --help'. Here are a few examples:</p>
|
||||
<!-- Thanks to
|
||||
http://shiflett.org/blog/2006/oct/formatting-and-highlighting-php-code-listings
|
||||
Site suggested using pre in CSS, but doesn't work in IE, so went for the <pre>
|
||||
tag. -->
|
||||
|
||||
<pre class="code">
|
||||
$ <b>cat ~/t.c</b>
|
||||
typedef float V __attribute__((vector_size(16)));
|
||||
V foo(V a, V b) { return a+b*a; }
|
||||
</pre>
|
||||
|
||||
|
||||
<h4>Preprocessing:</h4>
|
||||
|
||||
<pre class="code">
|
||||
$ <b>clang ~/t.c -E</b>
|
||||
# 1 "/Users/sabre/t.c" 1
|
||||
|
||||
typedef float V __attribute__((vector_size(16)));
|
||||
|
||||
V foo(V a, V b) { return a+b*a; }
|
||||
</pre>
|
||||
|
||||
|
||||
<h4>Type checking:</h4>
|
||||
|
||||
<pre class="code">
|
||||
$ <b>clang -fsyntax-only ~/t.c</b>
|
||||
</pre>
|
||||
|
||||
|
||||
<h4>GCC options:</h4>
|
||||
|
||||
<pre class="code">
|
||||
$ <b>clang -fsyntax-only ~/t.c -pedantic</b>
|
||||
/Users/sabre/t.c:2:17: warning: extension used
|
||||
typedef float V __attribute__((vector_size(16)));
|
||||
^
|
||||
1 diagnostic generated.
|
||||
</pre>
|
||||
|
||||
|
||||
<h4>Pretty printing from the AST:</h4>
|
||||
|
||||
<pre class="code">
|
||||
$ <b>clang ~/t.c -ast-print</b>
|
||||
typedef float V __attribute__(( vector_size(16) ));
|
||||
V foo(V a, V b) {
|
||||
return a + b * a;
|
||||
}
|
||||
</pre>
|
||||
|
||||
|
||||
<h4>Code generation with LLVM:</h4>
|
||||
|
||||
<pre class="code">
|
||||
$ <b>clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llvm-dis</b>
|
||||
define <4 x float> @foo(<4 x float> %a, <4 x float> %b) {
|
||||
entry:
|
||||
%mul = mul <4 x float> %b, %a
|
||||
%add = add <4 x float> %mul, %a
|
||||
ret <4 x float> %add
|
||||
}
|
||||
$ <b>clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=ppc32 -mcpu=g5</b>
|
||||
..
|
||||
_foo:
|
||||
vmaddfp v2, v3, v2, v2
|
||||
blr
|
||||
$ <b>clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=x86 -mcpu=yonah</b>
|
||||
..
|
||||
_foo:
|
||||
mulps %xmm0, %xmm1
|
||||
addps %xmm0, %xmm1
|
||||
movaps %xmm1, %xmm0
|
||||
ret
|
||||
</pre>
|
||||
|
||||
<h3>GCC "Emulation" Driver</h3>
|
||||
|
||||
While the <tt>clang</tt> executable is a compiler driver that can perform code
|
||||
generation, program analysis, and other actions, it is not designed to be a
|
||||
drop-in replacement for GCC's <tt>cc</tt>. There is interest in developing such
|
||||
a driver for clang, but in the interim the clang source tree includes a Python
|
||||
script <tt>ccc</tt> in the <tt>utils</tt> subdirectory that provides some of
|
||||
this functionality (the script is intended to be used where GCC's <tt>cc</tt>
|
||||
could be used). It is currently a work in progress, and eventually will likely
|
||||
be replaced by a more complete driver.
|
||||
|
||||
<p>Example use:</p>
|
||||
|
||||
<pre class="code">
|
||||
$ <b>ccc t.c</b>
|
||||
clang -emit-llvm-bc -o t.o -U__GNUC__ t.c
|
||||
llvm-ld -native -o a.out t.o
|
||||
$ <b>ls</b>
|
||||
a.out a.out.bc t.c t.o
|
||||
</pre>
|
||||
|
||||
|
||||
|
||||
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
|
|
Loading…
Reference in New Issue