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authorChris Lattner <sabre@nondot.org>2002-09-09 19:58:18 +0000
committerChris Lattner <sabre@nondot.org>2002-09-09 19:58:18 +0000
commitcaa5d13cda3902b5c120089c6b3866eb294ab4eb (patch)
tree77218c0fdb814c8cab8b7162db707ce05d8bf615 /docs
parentd8aabb20e81dd934425903466ba2544659dc6fb0 (diff)
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* Write the prose for the Basic Inspection and Traversal Routines section
* Fix some minor problems with &lt; and &amp; * Add links to later parts of the document for classes git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3636 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
-rw-r--r--docs/ProgrammersManual.html50
1 files changed, 33 insertions, 17 deletions
diff --git a/docs/ProgrammersManual.html b/docs/ProgrammersManual.html
index 36e5920068..20340c2981 100644
--- a/docs/ProgrammersManual.html
+++ b/docs/ProgrammersManual.html
@@ -218,13 +218,26 @@ that you should know about.<p>
<a name="inspection">Basic Inspection and Traversal Routines</a>
</b></font></td></tr></table><ul>
+The LLVM compiler infrastructure have many different data structures that may be
+traversed. Following the example of the C++ standard template library, the
+techniques used to traverse these various data structures are all basically the
+same. For a enumerable sequence of values, the <tt>XXXbegin()</tt> function (or
+method) returns an iterator to the start of the sequence, the <tt>XXXend()</tt>
+function returns an iterator pointing to one past the last valid element of the
+sequence, and there is some <tt>XXXiterator</tt> data type that is common
+between the two operations.<p>
+
+Because the pattern for iteration is common across many different aspects of the
+program representation, the standard template library algorithms may be used on
+them, and it is easier to remember how to iterate. First we show a few common
+examples of the data structures that need to be traversed. Other data
+structures are traversed in very similar ways.<p>
-<!-- LLVM has heirarchical representation: Module, Function, BasicBlock,
-Instruction. Common patterns for all levels. -->
<!-- _______________________________________________________________________ -->
-</ul><h4><a name="iterate_function"><hr size=0>Iterating over the
-<tt>BasicBlock</tt>s in a <tt>Function</tt> </h4><ul>
+</ul><h4><a name="iterate_function"><hr size=0>Iterating over the <a
+href="#BasicBlock"><tt>BasicBlock</tt></a>s in a <a
+href="#Function"><tt>Function</tt></a> </h4><ul>
It's quite common to have a <tt>Function</tt> instance that you'd like
to transform in some way; in particular, you'd like to manipulate its
@@ -253,8 +266,9 @@ classes. In the above code, the expression <tt>i->size()</tt> is
exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
<!-- _______________________________________________________________________ -->
-</ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the
-<tt>Instruction</tt>s in a <tt>BasicBlock</tt> </h4><ul>
+</ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the <a
+href="#Instruction"><tt>Instruction</tt></a>s in a <a
+href="#BasicBlock"><tt>BasicBlock</tt></a> </h4><ul>
Just like when dealing with <tt>BasicBlock</tt>s in
<tt>Function</tt>s, it's easy to iterate over the individual
@@ -263,10 +277,10 @@ that prints out each instruction in a <tt>BasicBlock</tt>:
<pre>
// blk is a pointer to a BasicBlock instance
- for(BasicBlock::iterator i = blk-&gt;begin(), e = blk-&gt;end(); i != e; ++i) {
+ for(BasicBlock::iterator i = blk-&gt;begin(), e = blk-&gt;end(); i != e; ++i)
// the next statement works since operator&lt;&lt;(ostream&amp;,...)
// is overloaded for Instruction&amp;
- cerr &lt;&lt; *i &lt;&lt; endl;
+ cerr &lt;&lt; *i &lt;&lt; "\n";
</pre>
However, this isn't really the best way to print out the contents of a
@@ -281,21 +295,23 @@ the pointer value you might expect. This is a deprecated interface that will
be removed in the future, so it's best not to depend on it. To print out the
pointer value for now, you must cast to <tt>void*</tt>.<p>
+
<!-- _______________________________________________________________________ -->
-</ul><h4><a name="iterate_institer"><hr size=0>Iterating over the
-<tt>Instruction</tt>s in a <tt>Function</tt></h4><ul>
+</ul><h4><a name="iterate_institer"><hr size=0>Iterating over the <a
+href="#Instruction"><tt>Instruction</tt></a>s in a <a
+href="#Function"><tt>Function</tt></a></h4><ul>
If you're finding that you commonly iterate over a <tt>Function</tt>'s
<tt>BasicBlock</tt>s and then that <tt>BasicBlock</tt>'s
<tt>Instruction</tt>s, <tt>InstIterator</tt> should be used instead.
-You'll need to include <tt>llvm/Support/InstIterator.h</tt>, and then
+You'll need to include <a href="/doxygen/InstIterator_8h-source.html"><tt>llvm/Support/InstIterator.h</tt></a>, and then
instantiate <tt>InstIterator</tt>s explicitly in your code. Here's a
small example that shows how to dump all instructions in a function to
stderr (<b>Note:</b> Dereferencing an <tt>InstIterator</tt> yields an
<tt>Instruction*</tt>, <i>not</i> an <tt>Instruction&amp</tt>!):
<pre>
-#include "llvm/Support/InstIterator.h"
+#include "<a href="/doxygen/InstIterator_8h-source.html">llvm/Support/InstIterator.h</a>"
...
// Suppose F is a ptr to a function
for(inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
@@ -352,7 +368,7 @@ still need the following in order for things to work properly:
<pre>
BasicBlock::iterator bbi = ...;
-BranchInst* b = dyn_cast&lt;BranchInst&gt;(&amp*bbi);
+<a href="#BranchInst">BranchInst</a>* b = <a href="#isa">dyn_cast</a>&lt;<a href="#BranchInst">BranchInst</a>&gt;(&amp;*bbi);
</pre>
It's also possible to turn a class pointer into the corresponding
@@ -366,7 +382,7 @@ over some structure:
void printNextInstruction(Instruction* inst) {
BasicBlock::iterator it(inst);
++it; // after this line, it refers to the instruction after *inst.
- if(it != inst-&gt;getParent()->end()) cerr &lt;&lt *it &lt;&lt endl;
+ if(it != inst-&gt;getParent()->end()) cerr &lt;&lt; *it &lt;&lt; "\n";
}
</pre>
Of course, this example is strictly pedagogical, because it'd be much
@@ -411,10 +427,10 @@ class OurFunctionPass : public FunctionPass {
public:
OurFunctionPass(): callCounter(0) { }
- virtual runOnFunction(Function&amp F) {
+ virtual runOnFunction(Function&amp; F) {
for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
for(BasicBlock::iterator i = b-&gt;begin(); ie = b-&gt;end(); i != ie; ++i) {
- if(CallInst* callInst = dyn_cast<CallInst>(&amp;*inst)) {
+ if (<a href="#CallInst">CallInst</a>* callInst = dyn_cast&lt;<a href="#CallInst">CallInst</a>&gt;(&amp;*inst)) {
// we know we've encountered a call instruction, so we
// need to determine if it's a call to the
// function pointed to by m_func or not.
@@ -1280,6 +1296,6 @@ pointer to the parent Function.
<a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
<!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
<!-- hhmts start -->
-Last modified: Mon Sep 9 11:29:35 CDT 2002
+Last modified: Mon Sep 9 14:56:55 CDT 2002
<!-- hhmts end -->
</font></body></html>