clayborg added a comment.
So overall approach is good. See inline comments for issue and questions.
================
Comment at: lldb/source/Plugins/ObjectFile/ELF/ELFHeader.cpp:371-373
+ r.st_name = st_name;
+ return elf::ELFSymbol::operator==(r) &&
+ st_name_string == rhs.st_name_string;
----------------
I would almost just manually compare only the things we care about here. Again,
what about st_shndx when comparing a symbol from the main symbol table and one
from the .gnu_debugdata symbol table. Are those section indexes guaranteed to
match? I would think not.
================
Comment at: lldb/source/Plugins/ObjectFile/ELF/ELFHeader.h:289
+struct NamedELFSymbol : ELFSymbol {
+ lldb_private::ConstString st_name_string; ///< Actual name of the ELF symbol
+
----------------
Do we need a ConstString for the st_shndx as well so we can correctly compare a
section from one file to a section from another as in the .gnu_debugdata case?
================
Comment at: lldb/source/Plugins/ObjectFile/ELF/ELFHeader.h:427
+ std::size_t h2 = std::hash<elf::elf_xword>()(s.st_size);
+ std::size_t h3 = std::hash<elf::elf_word>()(s.st_name);
+ std::size_t h4 = std::hash<unsigned char>()(s.st_info);
----------------
An ELF symbol from one symbol table can have the same name as another yet with
a different st_name string table offset. Do we even want to be able to hash an
ELFSymbol on its own? Maybe remove this enture function and only hash
NamedELFSymbol?
================
Comment at: lldb/source/Plugins/ObjectFile/ELF/ELFHeader.h:430
+ std::size_t h5 = std::hash<unsigned char>()(s.st_other);
+ std::size_t h6 = std::hash<elf::elf_half>()(s.st_shndx);
+ return llvm::hash_combine(h1, h2, h3, h4, h5, h6);
----------------
I know the section index will match between for symbol tables in the same ELF
file, but what about a symbol table in an external file like .gnu_debugdata?
================
Comment at: lldb/source/Plugins/ObjectFile/ELF/ELFHeader.h:440
+ tmp.st_name = 0;
+ std::size_t h1 = std::hash<elf::ELFSymbol>()(tmp);
+ std::size_t h2 = std::hash<const char *>()(s.st_name_string.AsCString());
----------------
Don't we need to hash everything we care about except the st_name? Those
indexes can differ if they come from a different string table? Shouldn't this
be:
```
std::size_t h1 = std::hash<elf::elf_addr>()(s.st_value);
std::size_t h2 = std::hash<elf::elf_xword>()(s.st_size);
// Skip std::size_t h3 = std::hash<elf::elf_word>()(s.st_name);
std::size_t h4 = std::hash<unsigned char>()(s.st_info);
std::size_t h5 = std::hash<unsigned char>()(s.st_other);
std::size_t h6 = std::hash<elf::elf_half>()(s.st_shndx);
std::size_t h7 = std::hash<const char *>()(s.st_name_string.AsCString());
return llvm::hash_combine(h1, h2, h4, h5, h6, h7);
```
I left the "h" variables with the same names to show we don't want "h3".
================
Comment at: lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp:2202-2206
+ NamedELFSymbol needle(symbol);
+ needle.st_name_string = ConstString(symbol_bare);
+ if (unique_elf_symbols.find(needle) == unique_elf_symbols.end()) {
+ symtab->AddSymbol(dc_symbol);
+ unique_elf_symbols.insert(needle);
----------------
Do we even need NamedELFSymbol? Can we just make an unordered_set of
lldb_private::Symbol values?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D67390/new/
https://reviews.llvm.org/D67390
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