If a stack trace or similar has a list of addresses from an executable
or DSO loaded at a variable address (e.g. due to ASLR), the addresses
will not directly correspond to the addresses stored in the object file.
If a user wishes to use llvm-symbolizer, they have to subtract the load
address from every address. This is somewhat inconvenient, especially as
the output of --print-address will result in the adjusted address being
listed, rather than the address coming from the stack trace, making it
harder to map results between the two.
This change adds a new switch to llvm-symbolizer --adjust-vma which
takes an offset, which is then used to automatically do this
calculation. The printed address remains the input address (allowing for
easy mapping), whilst the specified offset is applied to the addresses
when performing the lookup.
The switch is conceptually similar to llvm-objdump's new switch of the
same name (see D57051), which in turn mirrors a GNU switch. There is no
equivalent switch in addr2line.
Reviewed by: grimar
Differential Revision: https://reviews.llvm.org/D57151
llvm-svn: 352195
James Henderson