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Mention breakpoint names in the tutorial.

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llvm-svn: 313305
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Jim Ingham
2017-09-14 22:20:31 +00:00
parent 8635f7d2c6
commit 5cd216650f
1 changed files with 64 additions and 3 deletions
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lldb/www/tutorial.html
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@@ -248,9 +248,9 @@
</div>
<div class="postfooter"></div>
<div class="post">
<h1 class ="postheader">Setting breakpoints</h1>
<div class="postcontent">
<div class="post">
<h1 class ="postheader">Setting breakpoints</h1>
<div class="postcontent">
<p>We've discussed how to set breakpoints above. You can use <code>help breakpoint set</code>
to see all the options for breakpoint setting. For instance, we might do:</p>
@@ -350,6 +350,67 @@ Current breakpoints:
</div>
<div class="postfooter"></div>
<div class="post">
<h1 class ="postheader">Breakpoint Names</h1>
<div class="postcontent">
<p>Breakpoints carry two orthognal sets of information: one specifies where to
set the breakpoint, and the other how to react when the breakpoint is hit.
The latter set of information (e.g. commands, conditions, hit-count, auto-continue...)
we call breakpoint options.</p>
<p>It is fairly common to want to apply one set of options to a number of breakpoints.
For instance, you might want to check that <code>self == nil</code> and if it is,
print a backtrace and continue, on a number of methods.
One convenient way to do that would be to make all
the breakpoints, then configure the options with:</p>
<code>
(lldb) breakpoint modify -c "self == nil" -C bt --auto-continue 1 2 3
</code>
<p>That's not too bad, but you have to repeat this for every new breakpoint you
make, and if you wanted to change the options, you have to remember all the ones you
are using this way.</p>
<p> Breakpoint names provide a convenient solution to this problem. The simple solution would
be to use the name to gather the breakpoints you want to affect this way into a group. So
when you make the breakpoint you would do:</p>
<code>
(lldb) breakpoint set <SPECIFICATION> -N SelfNil
</code>
<p>Then when you've made all your breakpoints, you can set up or modify the options using
the name to collect all the relevant breakpoints.</p>
<code>
(lldb) breakpoint modify -c "self == nil" -C bt --auto-continue SelfNil
</code>
<p> That is better, but suffers from the problem that when new breakpoints get added, they
don't pick up these modifications, and the options only exist in the context of actual
breakpoints, so they are hard to store & reuse. </p>
<p>A even better solution is to make a
fully configured breakpoint name:</p>
<code>
(lldb) breakpoint name configure -c "self == nil" -C bt --auto-continue SelfNil
</code>
<p>Then you can apply the name to your breakpoints, and they will all pick up these
options. The connection from name to breakpoints remains live, so when you change the
options configured on the name, all the breakpoints pick up those changes. This makes
it easy to use configured names to experiment with your options.</p>
<p>You can make breakpoint names in your .lldbinit file, so you can use them to
can behaviors that you have found useful and reapply them in future sessions.</p>
<p>You can also make a breakpoint name from the options set on a breakpoint:</p>
<code>
(lldb) breakpoint name configure -B 1 SelfNil
</code>
<p>which makes it easy to copy behavior from one breakpoint to a set of others.</p>
<div class="postfooter"></div>
<div class="post">
<h1 class ="postheader">Setting watchpoints</h1>
<div class="postcontent">