2014-12-06 08:28:05 +08:00
|
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
|
|
|
<head>
|
|
|
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
|
|
|
|
|
<link href="style.css" rel="stylesheet" type="text/css" />
|
|
|
|
|
<title>LLDB Tutorial</title>
|
|
|
|
|
</head>
|
|
|
|
|
|
|
|
|
|
<body>
|
|
|
|
|
<div class="www_title">
|
|
|
|
|
The SB API Coding Rules
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<div id="container">
|
|
|
|
|
<div id="content">
|
|
|
|
|
<!--#include virtual="sidebar.incl"-->
|
|
|
|
|
<div id="middle">
|
|
|
|
|
<div class="post">
|
|
|
|
|
<h1 class ="postheader">SB API Coding Rules</h1>
|
|
|
|
|
<div class="postcontent">
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<p>The SB APIs constitute the stable C++ API that lldb presents to external clients,
|
|
|
|
|
and which get processed by SWIG to produce the Python bindings to lldb. As such
|
|
|
|
|
it is important that they not suffer from the binary incompatibilities that C++ is
|
|
|
|
|
so susceptible to. We've established a few rules to ensure that this happens.
|
|
|
|
|
|
|
|
|
|
<p>The classes in the SB API's are all called SB<SomeName>, where SomeName is in CamelCase
|
|
|
|
|
starting with an upper case letter. The method names are all CamelCase with initial
|
|
|
|
|
capital letter as well.
|
|
|
|
|
|
|
|
|
|
<p>All the SB API classes are non-virtual, single inheritance classes. They should only include
|
|
|
|
|
SBDefines.h or other SB headers as needed. There should be no inlined method implementations
|
|
|
|
|
in the header files, they should all be in the implementation files. And there should be no
|
|
|
|
|
direct ivar access.
|
|
|
|
|
|
|
|
|
|
<p>You also need to choose the ivars for the class with care, since you can't add or remove ivars
|
|
|
|
|
without breaking binary compatibility. In some cases, the SB class is a thin wrapper around
|
|
|
|
|
an interal lldb_private object. In that case, the class can have a single ivar, which is
|
|
|
|
|
either a pointer, shared_ptr or unique_ptr to the object in the lldb_private API. All the
|
|
|
|
|
lldb_private classes that get used this way are declared as opaque classes in lldb_forward.h,
|
|
|
|
|
which is included in SBDefines.h. So if you need an SB class to wrap an lldb_private class
|
|
|
|
|
that isn't in lldb_forward.h, add it there rather than making a direct opaque declaration in
|
|
|
|
|
the SB classes .h file.
|
|
|
|
|
|
|
|
|
|
<p>If the SB Class needs some state of its own, as well as the backing object, don't include that
|
|
|
|
|
as a direct ivar in the SB Class. Instead, make an Impl class in the SB's .cpp file, and then
|
|
|
|
|
make the SB object hold a shared or unique pointer to the Impl object. The theory behind this is
|
|
|
|
|
that if you need more state in the SB object, those needs are likely to change over time,
|
|
|
|
|
and this way the impl class can pick up members without changing the size of the object.
|
|
|
|
|
An example of this is the SBValue class.
|
|
|
|
|
|
|
|
|
|
<p>In order to fit into the Python API's, we need to be able to default construct all the SB objects.
|
|
|
|
|
Since the ivars of the classes are all pointers of one sort or other, this can easily be done, but
|
|
|
|
|
it means all the methods must be prepared to handle their opaque implementation pointer being
|
|
|
|
|
empty, and doing something reasonable. We also always have an "IsValid" method on all the SB
|
|
|
|
|
classes to report whether the object is empty or not.
|
|
|
|
|
|
|
|
|
|
<p>Another piece of the SB API infrastructure is the Python (or other script interpreter) customization.
|
|
|
|
|
SWIG allows you to add property access, iterators and documentation to classes, but to do that you have to use
|
|
|
|
|
a Swig interface file in place of the .h file. Those files have a different format than a straight C++ header file. These
|
2015-04-24 08:38:53 +08:00
|
|
|
files are called SB<ClassName>.i, and live in "scripts/interface". They are constructed by
|
2014-12-06 08:28:05 +08:00
|
|
|
starting with the associated .h file, and adding documentation and the Python decorations, etc. We
|
|
|
|
|
do this in a decidedly low-tech way, by maintaining the two files in parallel. That simplifies the
|
|
|
|
|
build process, but it does mean that if you add a method to the C++ API's for an SB class, you have
|
|
|
|
|
to copy the interface to the .i file.
|
|
|
|
|
</div>
|
|
|
|
|
</body>
|
|
|
|
|
</html>
|
