Changes in directory llvm/docs:
CodingStandards.html updated: 1.29 -> 1.30
---
Log message:
Add documentation for how to use the new LLVM streams.
---
Diffs of the changes: (+75 -3)
CodingStandards.html | 78 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 75 insertions(+), 3 deletions(-)
Index: llvm/docs/CodingStandards.html
diff -u llvm/docs/CodingStandards.html:1.29 llvm/docs/CodingStandards.html:1.30
--- llvm/docs/CodingStandards.html:1.29 Mon Jul 31 15:18:48 2006
+++ llvm/docs/CodingStandards.html Fri Dec 8 19:20:34 2006
@@ -41,12 +41,15 @@
<li><a href="#hl_dontinclude">#include as Little as Possible</a></li>
<li><a href="#hl_privateheaders">Keep "internal" Headers
Private</a></li>
+ <li><a href="#ll_iostream"><tt>#include <iostream></tt> is
+ <em>forbidden</em></a></li>
</ol></li>
<li><a href="#micro">The Low Level Issues</a>
<ol>
<li><a href="#ll_assert">Assert Liberally</a></li>
<li><a href="#ll_ns_std">Do not use 'using namespace std'</a></li>
- <li><a href="#ll_virtual_anch">Provide a virtual method anchor for
clases in headers</a></li>
+ <li><a href="#ll_virtual_anch">Provide a virtual method anchor for
+ clases in headers</a></li>
<li><a href="#ll_preincrement">Prefer Preincrement</a></li>
<li><a href="#ll_avoidendl">Avoid <tt>std::endl</tt></a></li>
</ol></li>
@@ -55,7 +58,8 @@
</ol>
<div class="doc_author">
- <p>Written by <a href="mailto:[EMAIL PROTECTED]">Chris Lattner</a></p>
+ <p>Written by <a href="mailto:[EMAIL PROTECTED]">Chris Lattner</a> and
+ <a href="mailto:[EMAIL PROTECTED]">Bill Wendling</a></p>
</div>
@@ -482,6 +486,73 @@
</div>
+<!-- _______________________________________________________________________
-->
+<div class="doc_subsubsection">
+ <a name="ll_iostream"><tt>#include <iostream></tt> is forbidden</a>
+</div>
+
+<div class="doc_text">
+
+<p>The use of <tt>#include <iostream></tt> in library files is
+hereby <b><em>forbidden</em></b>. The primary reason for doing this is to
+support clients using LLVM libraries as part of larger systems. In particular,
+we statically link LLVM into some dynamic libraries. Even if LLVM isn't used,
+the static c'tors are run whenever an application start up that uses the
dynamic
+library. There are two problems with this:</p>
+
+<ol>
+ <li>The time to run the static c'tors impacts startup time of
+ applications—a critical time for gui apps.</li>
+ <li>The static c'tors cause the app to pull many extra pages of memory off
the
+ disk: both the code for the static c'tors in each .o file and the small
+ amount of data that gets touched. In addition, touched/dirty pages put
+ more pressure on the VM system on low-memory machines.</li>
+</ol>
+
+<table>
+ <tbody>
+ <tr>
+ <th>Old Way</th>
+ <th>New Way</th>
+ </tr>
+ <tr>
+ <td align="left"><pre>#include <iostream></pre></td>
+ <td align="left"><pre>#include "llvm/Support/Streams.h"</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>DEBUG(std::cerr << ...);</pre></td>
+ <td align="left"><pre>DOUT << ...;</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>std::cerr << "Hello world\n";</pre></td>
+ <td align="left"><pre>llvm::cerr << "Hello world\n";</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>std::cout << "Hello world\n";</pre></td>
+ <td align="left"><pre>llvm::cout << "Hello world\n";</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>std::cin >> Var;</pre></td>
+ <td align="left"><pre>llvm::cin >> Var;</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>std::ostream</pre></td>
+ <td align="left"><pre>llvm::OStream</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>std::istream</pre></td>
+ <td align="left"><pre>llvm::IStream</pre></td>
+ </tr>
+ <tr>
+ <td align="left"><pre>std::stringstream</pre></td>
+ <td align="left"><pre>llvm::StringStream</pre></td>
+ </tr>
+ </tbody>
+</table>
+
+</div>
+
+
<!-- =======================================================================
-->
<div class="doc_subsection">
<a name="micro">The Low Level Issues</a>
@@ -631,6 +702,7 @@
</div>
+
<!-- ***********************************************************************
-->
<div class="doc_section">
<a name="seealso">See Also</a>
@@ -672,7 +744,7 @@
<a href="mailto:[EMAIL PROTECTED]">Chris Lattner</a><br>
<a href="http://llvm.org";>LLVM Compiler Infrastructure</a><br>
- Last modified: $Date: 2006/07/31 20:18:48 $
+ Last modified: $Date: 2006/12/09 01:20:34 $
</address>
</body>
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