[llvm-commits] CVS: llvm/docs/SystemLibrary.html

Sat Jul 17 03:04:59 PDT 2004

Changes in directory llvm/docs:

SystemLibrary.html added (r1.1)

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Log message:

Initial (outline only) draft of the System Library requirements, design
and details documentation.

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Diffs of the changes:  (+201 -0)

Index: llvm/docs/SystemLibrary.html
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+ <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
+                       "http://www.w3.org/TR/html4/strict.dtd">
+ <html>
+ <head>
+   <title>System Library</title>
+   <link rel="stylesheet" href="llvm.css" type="text/css">
+ </head>
+ <body>
+ 
+ <div class="doc_title"> System Library</div>
+ 
+ <div class="doc_warning">Warning: This document is a work in progress.</div>
+ 
+ <ul>
+   <li><a href="#abstract">Abstract</a></li>
+   <li><a href="#requirements">System Library Requirements</a>
+   <ol>
+     <li><a href="#headers">Hide System Header Files</a></li>
+     <li><a href="#nofunc">No Exposed Functions</a></li>
+     <li><a href="#nodata">No Exposed Data</a></li>
+     <li><a href="#xcptns">No Exceptions</a></li>
+     <li><a href="#errors">Standard Error Codes</a></li>
+     <li><a href="#overhead">Minimize Overhead</a></li>
+   </ol></li>
+   <li><a href="#design">System Library Design</a>
+   <ol>
+     <li><a href="#opaque">Use Opaque Classes</a></li>
+     <li><a href="#common">Common Implementations</a></li>
+     <li><a href="#multi_imps">Multiple Implementations</a></li>
+     <li><a href="#lowlevel">Use Low Level Interfaces</a></li>
+     <li><a href="#memalloc">No Memory Allocation</a></li>
+     <li><a href="#virtuals">No Virtual Methods</a></li>
+   </ol></li>
+   <li><a href="#detail">System Library Details</a>
+   <ol>
+     <li><a href="#bug">Tracking Bugzilla Bug: 351</a></li>
+     <li><a href="#refimpl">Reference Implementatation</a></li>
+   </ol></li>
+ </ul>
+ 
+ <div class="doc_author">
+   <p>Written by the <a href="rspencer at x10sys.com">Reid Spencer</a></p>
+ </div>
+ 
+ 
+ <!-- *********************************************************************** -->
+ <div class="doc_section"><a name="abstract">Abstract</a></div>
+ <div class="doc_text">
+   <p>This document describes the requirements, design, and implementation 
+   details of LLVM's System Library. The library is composed of the header files
+   in <tt>llvm/include/llvm/System</tt> and the source files in 
+   <tt>llvm/lib/System</tt>. The goal of this library is to completely shield 
+   LLVM from the variations in operating system interfaces. By centralizing 
+   LLVM's use of operating system interfaces, we make it possible for the LLVM
+   tool chain and runtime libraries to be more easily ported to new platforms.
+   The library also unclutters the rest of LLVM from #ifdef use and special
+   cases for specific operating systems.</p>
+   <p>The System Library was donated to LLVM by Reid Spencer who formulated the
+   original design as part of the eXtensible Programming System (XPS) which is
+   based, in part, on LLVM.</p>
+ </div>
+ 
+ <!-- *********************************************************************** -->
+ <div class="doc_section">
+   <a name="requirements">System Library Requirements</a>
+ </div>
+ <div class="doc_text">
+   <p>The System library's requirements are aimed at shielding LLVM from the
+   variations in operating system interfaces. The following sections define the
+   requirements needed to fulfill this objective.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="headers">Hide System Header Files</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="nofunc">No Exposed Functions</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="nodata">No Exposed Data</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="xcptns">No Exceptions</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="errors">Standard Error Codes</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="overhead">Minimize Overhead</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- *********************************************************************** -->
+ <div class="doc_section"><a name="design">System Library Design</a></div>
+ <div class="doc_text">
+   <p>In order to fulfill the requirements of the system library, strict design
+   objectives must be maintained in the library as it evolves.  The goal here 
+   is to provide interfaces to operating system concepts (files, memory maps, 
+   sockets, signals, locking, etc) efficiently and in such a way that the 
+   remainder of LLVM is completely operating system agnostic.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="opaque">Use Opaque Classes</a></div>
+ <div class="doc_text">
+   <p>no public data</p>
+   <p>onlyprimitive typed private/protected data</p>
+   <p>data size is "right" for platform, not max of all platforms</p>
+   <p>each class corresponds to O/S concept</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="common">Common Implementations</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection">
+   <a name="multi_imps">Multiple Implementations</a>
+ </div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection">
+   <a name="low_level">Use Low Level Interfaces</a>
+ </div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="memalloc">No Memory Allocation</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="virtuals">No Virtual Methods</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- *********************************************************************** -->
+ <div class="doc_section"><a name="detail">System Library Details</a></div>
+ <div class="doc_text">
+   <p>To be written.</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection"><a name="bug">Bug 251</a></div>
+ <div class="doc_text">
+   <p>See <a href="http://llvm.cs.uiuc.edu/bugs/show_bug?bug=351">bug 351</a>
+   for further details on the progress of this work</p>
+ </div>
+ 
+ <!-- ======================================================================= -->
+ <div class="doc_subsection">
+   <a name="refimpl">Reference Implementation</a>
+ </div>
+ <div class="doc_text">
+   <p>The <tt>linux</tt> implementation of the system library will always be the
+   reference implementation. This means that (a) the concepts defined by the
+   linux must be identically replicated in the other implementations and (b) the
+   linux implementation must always be complete (provide implementations for all
+   concepts).</p>
+ </div>
+ 
+ <!-- *********************************************************************** -->
+ 
+ <hr>
+ <address>
+   <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
+   src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
+   <a href="http://validator.w3.org/check/referer"><img
+   src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
+ 
+   <a href="mailto:rspencer at x10sys.com">Reid Spencer</a><br>
+   <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
+   Last modified: $Date: 2004/07/17 10:04:49 $
+ </address>
+ </body>
+ </html>