add info on walking preds/succs of a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45537 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-01-03 16:56:04 +00:00
parent ae636f8e99
commit 2e438ca03b

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@ -103,6 +103,8 @@ complex example</a> </li>
the same way</a> </li>
<li><a href="#iterate_chains">Iterating over def-use &amp;
use-def chains</a> </li>
<li><a href="#iterate_preds">Iterating over predecessors &amp;
successors of blocks</a></li>
</ul>
</li>
<li><a href="#simplechanges">Making simple changes</a>
@ -1536,7 +1538,7 @@ the last line of the last example,</p>
<div class="doc_code">
<pre>
Instruction* pinst = &amp;*i;
Instruction *pinst = &amp;*i;
</pre>
</div>
@ -1544,7 +1546,7 @@ Instruction* pinst = &amp;*i;
<div class="doc_code">
<pre>
Instruction* pinst = i;
Instruction *pinst = i;
</pre>
</div>
@ -1612,8 +1614,7 @@ class OurFunctionPass : public FunctionPass {
href="#CallInst">CallInst</a>&gt;(&amp;*i)) {
// <i>We know we've encountered a call instruction, so we</i>
// <i>need to determine if it's a call to the</i>
// <i>function pointed to by m_func or not</i>
// <i>function pointed to by m_func or not.</i>
if (callInst-&gt;getCalledFunction() == targetFunc)
++callCounter;
}
@ -1622,7 +1623,7 @@ class OurFunctionPass : public FunctionPass {
}
private:
unsigned callCounter;
unsigned callCounter;
};
</pre>
</div>
@ -1674,7 +1675,7 @@ of <tt>F</tt>:</p>
<div class="doc_code">
<pre>
Function* F = ...;
Function *F = ...;
for (Value::use_iterator i = F-&gt;use_begin(), e = F-&gt;use_end(); i != e; ++i)
if (Instruction *Inst = dyn_cast&lt;Instruction&gt;(*i)) {
@ -1694,10 +1695,10 @@ the particular <tt>Instruction</tt>):</p>
<div class="doc_code">
<pre>
Instruction* pi = ...;
Instruction *pi = ...;
for (User::op_iterator i = pi-&gt;op_begin(), e = pi-&gt;op_end(); i != e; ++i) {
Value* v = *i;
Value *v = *i;
// <i>...</i>
}
</pre>
@ -1710,6 +1711,36 @@ for (User::op_iterator i = pi-&gt;op_begin(), e = pi-&gt;op_end(); i != e; ++i)
</div>
<!--_______________________________________________________________________-->
<div class="doc_subsubsection">
<a name="iterate_preds">Iterating over predecessors &amp;
successors of blocks</a>
</div>
<div class="doc_text">
<p>Iterating over the predecessors and successors of a block is quite easy
with the routines defined in <tt>"llvm/Support/CFG.h"</tt>. Just use code like
this to iterate over all predecessors of BB:</p>
<div class="doc_code">
<pre>
#include "llvm/Support/CFG.h"
BasicBlock *BB = ...;
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
BasicBlock *Pred = *PI;
// <i>...</i>
}
</pre>
</div>
<p>Similarly, to iterate over successors use
succ_iterator/succ_begin/succ_end.</p>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="simplechanges">Making simple changes</a>