We use llvm-symbolizer in some production systems, and we run it
against all possibly related files, including some that are not
ELF. We noticed that for some of those invalid files, llvm-symbolizer
would crash with SEGFAULT. Here is an example of such a file.
It is due to that in computeSymbolSizes, a loop uses condition
for (unsigned I = 0, N = Addresses.size() - 1; I < N; ++I) {
where if Addresses.size() is 0, N would overflow and causing the loop
to access invalid memory.
Instead of patching the loop conditions, the commit makes so that the
function returns early if Addresses is empty.
Validated by checking that llvm-symbolizer no longer crashes.
Patch by Teng Qin!
Differential Revision: https://reviews.llvm.org/D44285
llvm-svn: 330610
Sometimes, llvm-symbolizer gives wrong results due to incorrect sizes of some symbols. The reason for that was an incorrectly sorted array in computeSymbolSizes. The comparison function used subtraction of unsigned types, which is incorrect. Let's change this to return explicit -1 or 1.
Differential Revision: https://reviews.llvm.org/D26537
llvm-svn: 287028
On ELF that was already the case since getting the size of a symbol
never fails.
On MachO and COFF we could fail trying to get the section of a symbol. But
we don't really need the section, just the section number to know if two
symbols are in the same section or not.
llvm-svn: 240580
COFF and MachO only define symbol sizes for common symbols. Reflect that
in the class hierarchy by having a method for common symbols only in the base
and a general one in ELF.
This avoids the need of using a magic value for the size, which had a few
problems
* Most callers didn't check for it.
* The ones that did could not tell the magic value from a file actually having
that value.
llvm-svn: 240529
Adrian Prantl