Sometimes you are debugging a binary or a corefile which does not have the debug information you need. In this case you might want to load some type definitions on the fly, but unfortunately gdb does not have direct support for it. What we can do however is to compile an object file with the desired information and load it into the current instance. This can even be used for certain file formats and similar. We therefore provide a few tools to automate that.
For simple types, you can just create them on the fly. The command
types create foo struct foo { int x; };
will compile a file (and load it) that will contain the struct definition and create a variable using the type foo and
then load that symbol table. After that you should be able to see the type and use it.
For more complex types, using the command
types load foo test.h
will compile and load a file including the test.h and creating a variable of the type foo. This can be an existing
header, or your own local creation for more convenience.
Additionally we try to scan the systems include directory for all kinds of types and have it possible for them to omit the filename. This only works when ctags is installed.
Currently only as a proof of concept, this will create a symbol with the given address.
types symbolic foo 0x00007fffffffca98
will create a symbol named foo (of type void*) at that address. This will cause a .bss section to be created, which
can mess up several other things so be careful.
If all you want is this being shown at e.g. hexdump, see the annotation feature there.
Reruns ctags to populate the cache. The cache normally does this automatically after
vdb-types-cache-max-age
seconds in the background. With this command you can force it to do that (unless vdb-types-cache is disabled). The
command is run and processed in the background. With the default fancy prompt you can watch the progress when the
prompt refreshes.
vdb-types-ctags-cmd
Use this command as ctags. We expect an exuberant ctags compatible version, which may be named/located differently for your case.
vdb-types-ctags-parameters
In case you need to change the parameters to ctags for whatever reason
vdb-types-ctags-files
The files/directories to scan. Can be comma sperarated list.
vdb-types-cache
Whether or not to do the caching of the type information. Regeneration of the cache will be done always, but this makes the last state available right at the start (scanning whole trees can take minutes)