<li><a href="#AU::addRequired">The <tt>AnalysisUsage::addRequired<></tt> and <tt>AnalysisUsage::addRequiredTransitive<></tt> methods</a></li>
<li><a href="#AU::addPreserved">The <tt>AnalysisUsage::addPreserved<></tt> method</a></li>
<li><a href="#AU::examples">Example implementations of <tt>getAnalysisUsage</tt></a></li>
- <li><a href="#getAnalysis">The <tt>getAnalysis<></tt> and <tt>getAnalysisToUpdate<></tt> methods</a></li>
+ <li><a href="#getAnalysis">The <tt>getAnalysis<></tt> and
+<tt>getAnalysisIfAvailable<></tt> methods</a></li>
</ul></li>
<li><a href="#analysisgroup">Implementing Analysis Groups</a>
<ul>
<div class="doc_code"><pre>
static char ID;
- Hello() : FunctionPass((intptr_t)&ID) {}
+ Hello() : FunctionPass(&ID) {}
</pre></div><p>
<p> This declares pass identifier used by LLVM to identify pass. This allows LLVM to
<b>struct Hello</b> : <b>public</b> <a href="#FunctionPass">FunctionPass</a> {
static char ID;
- Hello() : FunctionPass((intptr_t)&ID) {}
+ Hello() : FunctionPass(&ID) {}
<b>virtual bool</b> <a href="#runOnFunction">runOnFunction</a>(Function &F) {
llvm::cerr << "<i>Hello: </i>" << F.getName() << "\n";
<tt>ModulePass</tt> indicates that your pass uses the entire program as a unit,
refering to function bodies in no predictable order, or adding and removing
functions. Because nothing is known about the behavior of <tt>ModulePass</tt>
-subclasses, no optimization can be done for their execution. A module pass
-can use function level passes (e.g. dominators) using getAnalysis interface
-<tt> getAnalysis<DominatorTree>(Function)</tt>. </p>
+subclasses, no optimization can be done for their execution.</p>
+
+<p>A module pass can use function level passes (e.g. dominators) using
+the getAnalysis interface
+<tt>getAnalysis<DominatorTree>(llvm::Function *)</tt> to provide the
+function to retrieve analysis result for, if the function pass does not require
+any module or immutable passes. Note that this can only be done for functions for which the
+analysis ran, e.g. in the case of dominators you should only ask for the
+DominatorTree for function definitions, not declarations.</p>
<p>To write a correct <tt>ModulePass</tt> subclass, derive from
<tt>ModulePass</tt> and overload the <tt>runOnModule</tt> method with the
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="getAnalysis">The <tt>getAnalysis<></tt> and <tt>getAnalysisToUpdate<></tt> methods</a>
+ <a name="getAnalysis">The <tt>getAnalysis<></tt> and
+<tt>getAnalysisIfAvailable<></tt> methods</a>
</div>
<div class="doc_text">
<p>
If your pass is capable of updating analyses if they exist (e.g.,
<tt>BreakCriticalEdges</tt>, as described above), you can use the
-<tt>getAnalysisToUpdate</tt> method, which returns a pointer to the analysis if
-it is active. For example:</p>
+<tt>getAnalysisIfAvailable</tt> method, which returns a pointer to the analysis
+if it is active. For example:</p>
<div class="doc_code"><pre>
...
- if (DominatorSet *DS = getAnalysisToUpdate<DominatorSet>()) {
+ if (DominatorSet *DS = getAnalysisIfAvailable<DominatorSet>()) {
<i>// A DominatorSet is active. This code will update it.</i>
}
...
<p>If you are writing an analysis or any other pass that retains a significant
amount of state (for use by another pass which "requires" your pass and uses the
<a href="#getAnalysis">getAnalysis</a> method) you should implement
-<tt>releaseMEmory</tt> to, well, release the memory allocated to maintain this
+<tt>releaseMemory</tt> to, well, release the memory allocated to maintain this
internal state. This method is called after the <tt>run*</tt> method for the
class, before the next call of <tt>run*</tt> in your pass.</p>
<hr>
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<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>