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| author | Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au> | 2012-10-15 17:10:06 +1100 |
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| committer | Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au> | 2012-10-15 17:10:06 +1100 |
| commit | be1de4be954c80875ad4108e0a33e8e131b2f2c0 (patch) | |
| tree | 1fbbecf276bf7c7bdcbb4dd446099d6d90eaa516 /clang/www/UniversalDriver.html | |
| parent | c4626a62754862d20b41e8a46a3574264ea80e6d (diff) | |
| parent | f1bd2e48c5324d3f7cda4090c87f8a5b6f463ce2 (diff) | |
Merge branch 'master' of ssh://bitbucket.org/czan/honours
Diffstat (limited to 'clang/www/UniversalDriver.html')
| -rw-r--r-- | clang/www/UniversalDriver.html | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/clang/www/UniversalDriver.html b/clang/www/UniversalDriver.html new file mode 100644 index 0000000..2d41a62 --- /dev/null +++ b/clang/www/UniversalDriver.html @@ -0,0 +1,87 @@ +<!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 - Universal Driver</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>The Clang Universal Driver Project</h1> + +<p>Clang is inherently a cross compiler, in that it is always capable of +building code for targets which are a different architecture or even operating +system from the one running the compiler. However, actually cross compiling in +practice involves much more than just generating the right assembly code for a +target, it also requires having an appropriate tool chain (assemblers, linkers), +access to header files and libraries for the target, and many other details (for +example, the calling convention or whether software floating point is in +use). Traditionally, compilers and development environments provide little +assistance with this process, so users do not have easy access to the powerful +underlying cross-compilation abilities of clang.</p> + +<p>We would like to solve this problem by defining a new model for how cross +compilation is done, based on the idea of a <i>universal driver</i>. The key +point of this model is that the user would always access the compiler through a +single entry point (e.g., <tt>/usr/bin/cc</tt>) and provide an argument +specifying the <i>configuration</i> they would like to target. Under the hood +this entry point (the universal driver) would have access to all the information +that the driver, compiler, and other tools need to build applications for that +target.</p> + +<p>This is a large and open-ended project. It's eventual success depends not +just on implementing the model, but also on getting buy-in from compiler +developers, operating system distribution vendors and the development community +at large. Our plan is to begin by defining a clear list of the problems we want +to solve and a proposed implementation (from the user perspective).</p> + +<p>This project is in the very early (i.e., thought experiment) stages of +development. Stay tuned for more information, and of course, patches +welcome!</p> + +<p>See also <a href="http://llvm.org/PR4127">PR4127</a>.</p> + +<h2>Existing Solutions and Related Work</h2> + +<ul> + <li>gcc's command line arguments <tt>-V</tt>, <tt>-B</tt>, <tt>-b</tt> are + generic but limited solutions to related problems. Similarly, <tt>-m32</tt> + and <tt>-m64</tt> solve a small subset of the problem for specific + architectures.</li> + + <li>gcc's <a href="http://www.airs.com/ian/configure/configure_8.html">multilibs</a> + solve the part of the problem that relates to finding appropriate libraries + and include files based on particular feature support (soft float, + etc.).</li> + + <li>Apple's "driver driver" supported by gcc and clang solve a subset of the + problem by supporting <tt>-arch</tt>. Apple also provides a tool chain which + supports <a href="http://en.wikipedia.org/wiki/Universal_binary">universal + binaries</a> and object files which may include data for multiple + architectures. See <a href="http://developer.apple.com/mac/library/technotes/tn2005/tn2137.html">TN2137</a> + for an example of how this is used.</li> + + <li>Many operating systems and environments solve the problem by installing + complete development environments (including the IDE, tools, header files, + and libraries) for a single tool chain. This is cumbersome for users and + does not match well with tools which are inherently capable of cross + compiling.</li> + + <li>The Debian <a href="http://wiki.debian.org/ArmEabiPort">ArmEabiPort</a> + wiki page for their work to support the ARM EABI provide an interesting + glimpse into how related issues impact the operating system distribution.</li> + + <li><a href="http://icculus.org/fatelf/">FatELF</a> is a proposal for bringing + Mac OS X like "Universal Binary" support to ELF based platforms.</li> + +</ul> + +</div> +</body> +</html> |