[llvm-commits] CVS: llvm/docs/ProgrammersManual.html

[Chris Lattner]

Changes in directory llvm/docs:

ProgrammersManual.html updated: 1.86 -> 1.87
---
Log message:

Add notes about MF.viewCFG() and friends.


---
Diffs of the changes:  (+40 -1)

 ProgrammersManual.html |   41 ++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 40 insertions(+), 1 deletion(-)


Index: llvm/docs/ProgrammersManual.html
diff -u llvm/docs/ProgrammersManual.html:1.86 llvm/docs/ProgrammersManual.html:1.87
--- llvm/docs/ProgrammersManual.html:1.86	Tue May 10 17:06:41 2005
+++ llvm/docs/ProgrammersManual.html	Sun Oct 16 20:36:23 2005
@@ -41,6 +41,7 @@
       <li>The <tt>InstVisitor</tt> template
       <li>The general graph API
 --> 
+      <li><a href="#ViewGraph">Viewing graphs while debugging code</a></li>
     </ul>
   </li>
   <li><a href="#common">Helpful Hints for Common Operations</a>
@@ -491,6 +492,44 @@
 
 </div>
 
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+  <a name="ViewGraph">Viewing graphs while debugging code</a>
+</div>
+
+<div class="doc_text">
+
+<p>Several of the important data structures in LLVM are graphs: for example
+CFGs made out of LLVM <a href="#BasicBlock">BasicBlock</a>s, CFGs made out of
+LLVM <a href="CodeGenerator.html#machinebasicblock">MachineBasicBlock</a>s, and
+<a href="CodeGenerator.html#selectiondag_intro">Instruction Selection
+DAGs</a>.  In many cases, while debugging various parts of the compiler, it is
+nice to instantly visualize these graphs.</p>
+
+<p>LLVM provides several callbacks that are available in a debug build to do
+exactly that.  If you call the <tt>Function::viewCFG()</tt> method, for example,
+the current LLVM tool will pop up a window containing the CFG for the function
+where each basic block is a node in the graph, and each node contains the
+instructions in the block.  Similarly, there also exists 
+<tt>Function::viewCFGOnly()</tt> (does not include the instructions), the
+<tt>MachineFunction::viewCFG()</tt> and <tt>MachineFunction::viewCFGOnly()</tt>,
+and the <tt>SelectionDAG::viewGraph()</tt> methods.  Within GDB, for example,
+you can usually use something like "<tt>call DAG.viewGraph()</tt>" to pop
+up a window.  Alternatively, you can sprinkle calls to these functions in your
+code in places you want to debug.</p>
+
+<p>Getting this to work requires a small amount of configuration.  On Unix
+systems with X11, install the <a href="http://www.graphviz.org">graphviz</a>
+toolkit, and make sure 'dot' and 'gv' are in your path.  If you are running on
+Mac OS/X, download and install the Mac OS/X <a 
+href="http://www.pixelglow.com/graphviz/">Graphviz program</a>, and add
+<tt>/Applications/Graphviz.app/Contents/MacOS/</tt> (or whereever you install
+it) to your path.  Once in your system and path are set up, rerun the LLVM
+configure script and rebuild LLVM to enable this functionality.</p>
+
+</div>
+
+
 <!-- *********************************************************************** -->
 <div class="doc_section">
   <a name="common">Helpful Hints for Common Operations</a>
@@ -2236,7 +2275,7 @@
   <a href="mailto:dhurjati at cs.uiuc.edu">Dinakar Dhurjati</a> and
   <a href="mailto:sabre at nondot.org">Chris Lattner</a><br>
   <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
-  Last modified: $Date: 2005/05/10 22:06:41 $
+  Last modified: $Date: 2005/10/17 01:36:23 $
 </address>
 
 </body>