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Release notes for segmented stacks.

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Patch by Sanjoy Das.

llvm-svn: 145416
This commit is contained in:
Rafael Espindola 2011-11-29 19:08:23 +00:00
parent 97cc6da56c
commit 8e06adec06
2 changed files with 5 additions and 8 deletions
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5
docs/ReleaseNotes.html
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@ -936,7 +936,10 @@ be used to verify some algorithms.
make it run faster:</p>
<ul>
<li>XXX: Segmented stacks.</li>
<li>LLVM can now produce code that works with libgcc
to <a href="SegmentedStacks.html">dynamically allocate stack
segments</a>, as opposed to allocating a worst-case chunk of
virtual memory for each thread.</li>
<li>LLVM generates substantially better code for indirect gotos due to a new
tail duplication pass, which can be a substantial performance win for
interpreter loops that use them.</li>

8
docs/SegmentedStacks.html
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@ -20,18 +20,12 @@
<li><a href="#alloca">Variable Sized Allocas</a></li>
</ol>
</li>
<li><a href="#results">Results</a>
<ol>
<li><a href="#go">Go on LLVM</a></li>
<li><a href="#abi">Runtime ABI</a></li>
</ol>
</li>
</ol>
<h2><a name="intro">Introduction</a></h2>
<div>
<p>
Segmented stack allows stack space to be allocated incrementally than as a monolithic chunk (of some worst case size) at thread initialization. This is done by allocating stack blocks (henceforth called <em>stacklets</em>) and linking them into a doubly linked list. The function prologue is responsible for checking if the current stacklet has enough space for the function to execute; and if not, call into the libgcc runtime to allocate more stack space. Support for segmented stacks on x86 / Linux is currently being worked on.
Segmented stack allows stack space to be allocated incrementally than as a monolithic chunk (of some worst case size) at thread initialization. This is done by allocating stack blocks (henceforth called <em>stacklets</em>) and linking them into a doubly linked list. The function prologue is responsible for checking if the current stacklet has enough space for the function to execute; and if not, call into the libgcc runtime to allocate more stack space. When using <tt>llc</tt>, segmented stacks can be enabled by adding <tt>-segmented-stacks</tt> to the command line.
</p>
<p>
The runtime functionality is <a href="http://gcc.gnu.org/wiki/SplitStacks">already there in libgcc</a>.