Blame - www/troubleshooting.html - fp2-dev/platform/external/lldb

Greg Clayton

2013-06-18 01:01:31 +0000

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Troubleshooting <strong>LLDB</strong>

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<h1 class ="postheader">File and line breakpoints are not getting hit</h1>

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<p>First you must make sure that your source files were compiled with

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debug information. Typically this means passing <code>-g</code> to the

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compiler when compiling your source file.

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</p>

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<p>When setting breakpoints in <b>implementation</b> source files

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(.c, cpp, cxx, .m, .mm, etc), LLDB by default will only search for compile units whose filename matches. If your

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code does tricky things like using <font color=purple>#include</font> to include source files:

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<font color=purple>#include</font> "bar.c"

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<font color=purple>#include</font> "baz.c"

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...

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</tt></pre></code>

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<p> This will cause breakpoints in "bar.c" to be inlined into the compile unit for "foo.c".

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If your code does this, or if your build system combines multiple files in some way such

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that breakpoints from one implementation file will be compiled into another implementation file,

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you will need to tell LLDB to always search for inlined breakpoint locations

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by adding the following line to your <code>~/.lldbinit</code> file:

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</p>

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<code><pre><tt>% <b>echo "settings set target.inline-breakpoint-strategy always" >> ~/.lldbinit</b></tt></pre></code>

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<p> This tells LLDB to always look in all compile units and search for breakpoint

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locations by file and line even if the implementation file doesn't match. Settings breakpoints

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in header files always searches all compile units because inline functions are commonly defined

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in header files and often cause multiple breakpoints to have source line information that matches

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the header files paths.

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</p>

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<p> If you set a file and line breakpoint using a full path to the source file, like Xcode does when setting a

Jason Molenda

3407e76

2013-07-16 21:11:29 +0000

[diff] [blame]

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breakpoint in its GUI on Mac OS X when you click in the gutter of the source view, this path must match

Greg Clayton

546a056

2013-06-18 01:01:31 +0000

[diff] [blame]

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the full paths in the debug information. If the paths mismatch, possibly due to

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passing in a resolved source file path that doesn't match an unresolved path in the debug

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information, this can cause breakpoints to not be resolved. Try setting breakpoints using the file

Jason Molenda

3407e76

2013-07-16 21:11:29 +0000

[diff] [blame]

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basename only.

Greg Clayton

546a056

2013-06-18 01:01:31 +0000

[diff] [blame]

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<p> If you are using an IDE and you move your project in your file system and build again, sometimes doing a

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clean then build will solve the issue.This will fix the issue if some .o files didn't get rebuilt

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after the move as the .o files in the build folder might still contain stale debug information with

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the old source locations.

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<h1 class ="postheader">How do I check if I have debug symbols?</h1>

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<p> Checking if a module has any compile units (source files) is a good way to check

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if there is debug information in a module:

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(lldb) <b>file /tmp/a.out</b>

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(lldb) <b>image list</b>

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[ 0] 71E5A649-8FEF-3887-9CED-D3EF8FC2FD6E 0x0000000100000000 /tmp/a.out

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/tmp/a.out.dSYM/Contents/Resources/DWARF/a.out

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[ 1] 6900F2BA-DB48-3B78-B668-58FC0CF6BCB8 0x00007fff5fc00000 /usr/lib/dyld

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....

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(lldb) <b>script lldb.target.module['/tmp/a.out'].GetNumCompileUnits()</b>

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1

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(lldb) <b>script lldb.target.module['/usr/lib/dyld'].GetNumCompileUnits()</b>

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0

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</tt></pre></code>

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<p> Above we can see that "/tmp/a.out" does have a compile unit, and "/usr/lib/dyld" does not.

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Jason Molenda

3407e76

2013-07-16 21:11:29 +0000

[diff] [blame]

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