Optimization: bulk-parse symbol tables (~20x faster iter_symbols)#653
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Optimization: bulk-parse symbol tables (~20x faster iter_symbols)#653DanielBotnik wants to merge 1 commit into
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Also, I couldn't find the project formatter :( I would go and manually restore unnecessary changes |
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@sevaa this seems of interest to your work to speed up pyelftools |
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Rebased onto main and added Type Annotations |
SymbolTableSection parsed every Elf_Sym individually through the recursive `construct` parser, each with its own stream seek, and resolved every name with a separate per-symbol cstring stream parse. On binaries with many symbols this dominates load time. iter_symbols() now reads the whole table once and decodes it with a single struct.Struct (struct.iter_unpack), slicing all names out of one string-table read; the per-symbol get_symbol() keeps the original construct parse as the authoritative single-symbol path. The st_info/st_other sub-Containers (<=256 distinct values per table) are interned, and the entry Container is built via __new__ + __dict__ assignment (what Container.__init__ does anyway) -- measured ~15% of this function over Container(**fields). Measured best-of-6, iter_symbols over a whole .symtab: MIPS BE32, 8675 syms: 205 ms -> 10 ms (~20x) ARM LE32, 6221 syms: 144 ms -> 7 ms (~21x) Class/endianness are read from self.structs (always set wherever the construct path worked), not self.elffile, so the fast path covers callers that build a SymbolTableSection without an ELFFile (e.g. cle's dynamic-symbol table) exactly as the old construct path did. The enum/bitfield members are decoded through value->name maps placed in elf/enums.py next to their forward enums, mirroring the existing DW_FORM_raw2name convention; an unnamed value stays the raw integer, matching construct's _default_=Pass Enum semantics, so the returned Symbol objects are indistinguishable from the slow path. Validated: full unittest suite (118), the readelf comparison across all 62 test binaries, and the examples suite all pass; symbol output is byte-identical to stock for MIPS BE32, ARM LE32 and x86-64 LE64. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Hey, Rebased again :) |
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Hey @sevaa, anyway we can push this forward? Thanks :) |
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@eliben any chance you can take a look at this? |
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@sevaa is the one here most interested in run-time performance optimizations. It's summer time, perhaps he's out on vacation? You'll have to be patient, @DanielBotnik, sorry. You can obviously use your fork for now - this is OSS, after all. |
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Just preoccupied elsewhere. It's OSS, as you mentioned :) I'll take a look. |
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SymbolTableSection parsed every Elf_Sym individually through the recursive
constructparser, each with its own stream seek, and resolved every name with a separate per-symbol cstring stream parse. On binaries with many symbols this dominates load time.iter_symbols() now:
Measured best-of-6, iter_symbols over a whole .symtab:
MIPS BE32, 8675 syms: 205 ms -> 10 ms (~20x)
ARM LE32, 6221 syms: 144 ms -> 7 ms (~21x)