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80 lines
2.9 KiB
ReStructuredText
80 lines
2.9 KiB
ReStructuredText
Debugging Firefox with LLDB
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===========================
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See http://lldb.llvm.org/index.html.
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Mozilla-specific lldb settings
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------------------------------
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There's an
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``.lldbinit`` `file <https://searchfox.org/mozilla-central/source/.lldbinit>`_
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in the Mozilla source tree, which applies recommended settings and
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includes a few type summaries and Mozilla-specific debugging commands
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via the lldbutils module (see
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`python/lldbutils/README.txt <https://searchfox.org/mozilla-central/source/python/lldbutils/README.txt>`__).
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For information about available features see the links above and the `Using
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LLDB to debug Gecko <http://mcc.id.au/blog/2014/01/lldb-gecko>`__ blog
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post.
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The in-tree ``.lldbinit`` should be loaded automatically in most cases
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when running lldb from the command line (e.g. using
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:ref:`mach`), but **not**
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when using Xcode. See :ref:`Debugging on macOS` for information on setting up
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Xcode.
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.. warning::
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LLDB warning: Xcode 5 only comes with lldb (gdb is gone). The
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introduction and use of UNIFIED_SOURCES in the source starting around
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November 2013 has broken the default LLDB configuration so that it
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will not manage to resolve breakpoints in files that are build using
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UNIFIED_SOURCES (the breakpoints will be listed as "pending", and
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lldb will not stop at them). To fix this add the following to your
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$HOME/.lldbinit file:
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.. code::
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# Mozilla's use of UNIFIED_SOURCES to include multiple source files into a
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# single compiled file breaks lldb breakpoint setting. This works around that.
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# See http://lldb.llvm.org/troubleshooting.html for more.
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settings set target.inline-breakpoint-strategy always
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Restart Xcode/lldb and restart your debugging session. If that still
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doesn't fix things then try closing Xcode/lldb, doing a clobber
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build, reopening Xcode/lldb, and restarting your debugging session.
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Starting a debugging session
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----------------------------
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Attaching to an existing process
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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You can attach to Firefox with following command:
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.. code::
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(lldb) process attach --name firefox
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Some versions of lldb causes crashes after attaching to Firefox.
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Running a new process
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~~~~~~~~~~~~~~~~~~~~~
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To start Firefox under the debugger, run ``lldb`` followed by "--",
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followed by the command line you'd like to run, like this:
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.. code:: bash
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$ lldb -- obj-ff-dbg/dist/Nightly.app/Contents/MacOS/firefox -no-remote -profile /path/to/profile
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Then set breakpoints you need and start the process:
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.. code::
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(lldb) breakpoint set --name nsInProcessTabChildGlobal::InitTabChildGlobal
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Breakpoint created: 1: name = 'nsInProcessTabChildGlobal::InitTabChildGlobal', locations = 0 (pending)
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WARNING: Unable to resolve breakpoint to any actual locations.
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(lldb) r
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Process 7602 launched: '/.../obj-ff-opt/dist/Nightly.app/Contents/MacOS/firefox' (x86_64)
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1 location added to breakpoint 1
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