This patch adds initial support for reading dynamic symbols from ELF binaries. Currently, STT_NOTYPE, STT_OBJECT, STT_FUNC, and STT_TLS are explicitly supported. Other symbol types are mapped to ELFSymbolType::Unknown to improve signal/noise ratio.
Symbols must meet two criteria to be read into in an ELFStub:
- The symbol's binding must be STB_GLOBAL or STB_WEAK.
- The symbol's visibility must be STV_DEFAULT or STV_PROTECTED.
This filters out symbols that aren't of interest during compile-time linking against a shared object.
This change uses DT_HASH and DT_GNU_HASH to determine the size of .dynsym. Using hash tables to determine the number of symbols in .dynsym allows llvm-elfabi to work on binaries without relying on section headers.