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authorGordon Henriksen <gordonhenriksen@mac.com>2007-09-27 19:31:36 +0000
committerGordon Henriksen <gordonhenriksen@mac.com>2007-09-27 19:31:36 +0000
commit326e24fff011f9f5af62bfd2dae964dcd4fd6792 (patch)
treecd1d8bfbf04f5daf5e358a377770b9ef219d3071 /docs/Lexicon.html
parent1ed37fdb3bf411f50f2f88dfb0ffe89a30ba16ca (diff)
downloadexternal_llvm-326e24fff011f9f5af62bfd2dae964dcd4fd6792.zip
external_llvm-326e24fff011f9f5af62bfd2dae964dcd4fd6792.tar.gz
external_llvm-326e24fff011f9f5af62bfd2dae964dcd4fd6792.tar.bz2
GarbageCollection.html is expanded to encompass the coming
capabilities. This is a major rewrite and is easier to read en toto rather than patchwise. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42414 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/Lexicon.html')
-rw-r--r--docs/Lexicon.html79
1 files changed, 76 insertions, 3 deletions
diff --git a/docs/Lexicon.html b/docs/Lexicon.html
index dac1ead..fbe0956 100644
--- a/docs/Lexicon.html
+++ b/docs/Lexicon.html
@@ -30,13 +30,19 @@
</tr>
<tr><th colspan="8"><b>- <a href="#D">D</a> -</b></th></tr>
<tr>
+ <td><a href="#DAG">DAG</a></td>
+ <td><a href="#Derived_Pointer">Derived Pointer</a></td>
<td><a href="#DSA">DSA</a></td>
<td><a href="#DSE">DSE</a></td>
</tr>
+ <tr><th colspan="8"><b>- <a href="#G">G</a> -</b></th></tr>
+ <td><a href="#GC">GC</a></td>
+ </tr>
<tr><th colspan="8"><b>- <a href="#I">I</a> -</b></th></tr>
<tr>
<td><a href="#IPA">IPA</a></td>
<td><a href="#IPO">IPO</a></td>
+ <td><a href="#ISel">ISel</a></td>
</tr>
<tr><th colspan="8"><b>- <a href="#L">L</a> -</b></th></tr>
<tr>
@@ -44,6 +50,10 @@
<td><a href="#LICM">LICM</a></td>
<td><a href="#Load-VN">Load-VN</a></td>
</tr>
+ <tr><th colspan="8"><b>- <a href="#O">O</a> -</b></th></tr>
+ <tr>
+ <td><a href="#Object_Pointer">Object Pointer</a></td>
+ </tr>
<tr><th colspan="8"><b>- <a href="#P">P</a> -</b></th></tr>
<tr>
<td><a href="#PRE">PRE</a></td>
@@ -51,13 +61,16 @@
<tr><th colspan="8"><b>- <a href="#R">R</a> -</b></th></tr>
<tr>
<td><a href="#Reassociation">Reassociation</a></td>
+ <td><a href="#Root">Root</a></td>
</tr>
<tr><th colspan="8"><b>- <a href="#S">S</a> -</b></th></tr>
<tr>
+ <td><a href="#Safe_Point">Safe Point</a></td>
<td><a href="#SCC">SCC</a></td>
<td><a href="#SCCP">SCCP</a></td>
+ <td><a href="#SDISel">SDISel</a></td>
<td><a href="#SRoA">SRoA</a></td>
- <td><a href="#SSA">SSA</a></td>
+ <td><a href="#Stack_Map">Stack Map</a></td>
</tr>
</table>
</div>
@@ -92,13 +105,23 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
subexpression compuation. For example <tt>(a+b)*(a+b)</tt> has two
subexpressions that are the same: <tt>(a+b)</tt>. This optimization would
perform the addition only once and then perform the multiply (but only if
- its compulationally correct/safe).
+ it's compulationally correct/safe).
</dl>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="D">- D -</a></div>
<div class="doc_text">
<dl>
+ <dt><a name="DAG"><b>DAG</b></a></dt>
+ <dd>Directed Acyclic Graph</dd>
+ <dt><a name="Derived_Pointer"><b>Derived Pointer</b></a></dt>
+ <dd>A pointer to the interior of an object, such that a garbage collector
+ is unable to use the pointer for reachability analysis. While a derived
+ pointer is live, the corresponding object pointer must be kept in a root,
+ otherwise the collector might free the referenced object. With copying
+ collectors, derived pointers pose an additional hazard that they may be
+ invalidated at any <a href="Safe_Point">safe point</a>. This term is used in
+ opposition to <a href="#Object_Pointer">object pointer</a>.</dd>
<dt><a name="DSA"><b>DSA</b></a></dt>
<dd>Data Structure Analysis</dd>
<dt><a name="DSE"><b>DSE</b></a></dt>
@@ -106,6 +129,24 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
</dl>
</div>
<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"><a name="G">- G -</a></div>
+<div class="doc_text">
+ <dl>
+ <dt><a name="GC"><b>GC</b></a></dt>
+ <dd>Garbage Collection. The practice of using reachability analysis instead
+ of explicit memory management to reclaim unused memory.</dd>
+ </dl>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"><a name="H">- H -</a></div>
+<div class="doc_text">
+ <dl>
+ <dt><a name="Heap"><b>Heap</b></a></dt>
+ <dd>In garbage collection, the region of memory which is managed using
+ reachability analysis.</dd>
+ </dl>
+</div>
+<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="I">- I -</a></div>
<div class="doc_text">
<dl>
@@ -116,6 +157,8 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
<dd>Inter-Procedural Optimization. Refers to any variety of code
optimization that occurs between procedures, functions or compilation units
(modules).</dd>
+ <dt><a name="IPO"><b>ISel</b></a></dt>
+ <dd>Instruction Selection.</dd>
</dl>
</div>
<!-- _______________________________________________________________________ -->
@@ -132,6 +175,17 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
</div>
<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"><a name="P">- O -</a></div>
+<div class="doc_text">
+ <dl>
+ <dt><a name="Object_Pointer"><b>Object Pointer</b></a></dt>
+ <dd>A pointer to an object such that the garbage collector is able to trace
+ references contained within the object. This term is used in opposition to
+ <a href="#Derived_Pointer">derived pointer</a>.</dd>
+ </dl>
+</div>
+
+<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="P">- P -</a></div>
<div class="doc_text">
<dl>
@@ -147,7 +201,12 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
<dt><a name="Reassociation"><b>Reassociation</b></a></dt> <dd>Rearranging
associative expressions to promote better redundancy elimination and other
optimization. For example, changing (A+B-A) into (B+A-A), permitting it to
- be optimized into (B+0) then (B).
+ be optimized into (B+0) then (B).</dd>
+ <dt><a name="Root"><b>Root</b></a></dt> <dd>In garbage collection, a
+ pointer variable lying outside of the <a href="#Heap">heap</a> from which
+ the collector begins its reachability analysis. In the context of code
+ generation, "root" almost always refers to a "stack root"&#151;a local or
+ temporary variable within an executing function.</dd>
</dl>
</div>
@@ -155,6 +214,16 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
<div class="doc_subsection"><a name="S">- S -</a></div>
<div class="doc_text">
<dl>
+ <dt><a name="SCC"><b>Safe Point</b></a></dt>
+ <dd>In garbage collection, it is necessary to identify <a href="#Root">stack
+ roots</a> so that reachability analysis may proceed. It may be infeasible to
+ provide this information for every instruction, so instead the information
+ may is calculated only at designated safe points. With a copying collector,
+ <a href="#Derived_Pointers">derived pointers</a> must not be retained across
+ safe points and <a href="#Object_Pointers">object pointers</a> must be
+ reloaded from stack roots.</dd>
+ <dt><a name="SDISel"><b>SDISel</b></a></dt>
+ <dd>Selection DAG Instruction Selection.</dd>
<dt><a name="SCC"><b>SCC</b></a></dt>
<dd>Strongly Connected Component</dd>
<dt><a name="SCCP"><b>SCCP</b></a></dt>
@@ -163,6 +232,10 @@ href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
<dd>Scalar Replacement of Aggregates</dd>
<dt><a name="SSA"><b>SSA</b></a></dt>
<dd>Static Single Assignment</dd>
+ <dt><a name="Stack_Map"><b>Stack Map</b></a></dt>
+ <dd>In garbage collection, metadata emitted by the code generator which
+ identifies <a href="#Root">roots</a> within the stack frame of an executing
+ function.</dd>
</dl>
</div>
<!-- *********************************************************************** -->