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now with hackability. 

llvm-svn: 44784
This commit is contained in:
Chris Lattner 2007-12-10 07:23:52 +00:00
parent aa085d36e2
commit b6a8cfea24
2 changed files with 41 additions and 18 deletions
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3
clang/www/comparison.html
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@ -60,7 +60,8 @@
<p>Pro's of clang vs GCC:</p>
<ul>
<li>The Clang ASTs and design are intended to be easily understandable to
<li>The Clang ASTs and design are intended to be <a
href="features.html#simplecode">easily understandable</a> by
anyone who is familiar with the languages involved and who have a basic
understanding of how a compiler works. GCC has a very old codebase
which presents a steep learning curve to new developers.</li>

56
clang/www/features.html
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@ -27,16 +27,17 @@ These features are:
<ul>
<li><a href="#performance">High Performance and Low Memory Use</a></li>
<li><a href="#expressivediags">Expressive Diagnostics</a></a></li>
<li><a href="#gcccompat">GCC compatibility</a></li>
</ul>
<p>Driving Goals and Internal Design:</p>
<ul>
<li><a href="#real">A real-world, production quality compiler</a></li>
<li><a href="#simplecode">A simple and hackable code base</a></li>
<li><a href="#unifiedparser">A single unified parser for C, Objective C, C++,
and Objective C++</a></li>
<li><a href="#conformance">Conformance with C/C++/ObjC and their
variants</a></li>
<li><a href="#gcccompat">GCC compatibility</a></li>
</ul>
<!--=======================================================================-->
@ -147,6 +148,26 @@ std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;</tt>"!), but it is
also very useful in C code in some cases as well (e.g. "<tt>__m128"</tt> vs
"<tt>float __attribute__((__vector_size__(16)))</tt>").</p>
<!--=======================================================================-->
<h2><a name="gcccompat">GCC Compatibility</a></h2>
<!--=======================================================================-->
<p>GCC is currently the defacto-standard open source compiler today, and it
routinely compiles a huge volume of code. GCC supports a huge number of
extensions and features (many of which are undocumented) and a lot of
code and header files depend on these features in order to build.</p>
<p>While it would be nice to be able to ignore these extensions and focus on
implementing the language standards to the letter, pragmatics force us to
support the GCC extensions that see the most use. Many users just want their
code to compile, they don't care to argue about whether it is pedantically C99
or not.</p>
<p>As mentioned above, all
extensions are explicitly recognized as such and marked with extension
diagnostics, which can be mapped to warnings, errors, or just ignored.
</p>
<!--=======================================================================-->
<h1>Driving Goals and Internal Design</h1>
@ -170,6 +191,23 @@ being used and depended on by a broad range of people. While we are still in
the early development stages, we strongly believe that this will become a
reality.</p>
<!--=======================================================================-->
<h2><a name="simplecode">A simple and hackable code base</a></h2>
<!--=======================================================================-->
<p>Our goal is to make it possible for anyone with a basic understanding
of compilers and working knowledge of the C/C++/ObjC languages to understand and
extend the clang source base. A large part of this falls out of our decision to
make the AST mirror the languages as closely as possible: you have your friendly
if statement, for statement, parenthesis expression, structs, unions, etc, all
represented in a simple and explicit way.</p>
<p>In addition to a simple design, we work to make the source base approachable
by commenting it well, including citations of the language standards where
appropriate, and designing the code for simplicity. Beyond that, clang offers
a set of AST dumpers, printers, and visualizers that make it easy to put code in
and see how it is represented.</p>
<!--=======================================================================-->
<h2><a name="unifiedparser">A single unified parser for C, Objective C, C++,
and Objective C++</a></h2>
@ -209,22 +247,6 @@ clang in "strict" mode if you desire.</p>
<p>We also intend to support "dialects" of these languages, such as C89, K&amp;R
C, C++'03, Objective-C 2, etc.</p>
<!--=======================================================================-->
<h2><a name="gcccompat">GCC Compatibility</a></h2>
<!--=======================================================================-->
<p>GCC is currently the defacto-standard open source compiler today, and it
routinely compiles a huge volume of code. GCC supports a huge number of
extensions and features (many of which are undocumented) and a lot of
code and header files depend on these features in order to build.</p>
<p>While it would be nice to be able to ignore these extensions and focus on
implementing the language standards to the letter, pragmatics force us to
support the GCC extensions that see the most use. As mentioned above, all
extensions are explicitly recognized as such and marked with extension
diagnostics, which can be mapped to warnings, errors, or just ignored.
</p>
<!--=======================================================================-->
<h2><a name="libraryarch">Library based architecture</a></h2>