Cider Isn't Darwin Emulation, Really
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1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374#!/usr/bin/env python3"""Which symbols anything in a tree needs that NOTHING in that tree defines.
scripts/symbol-gap.py <tree> e.g. the built prefix's libexec/cider
macho-undefined.py answers this for ONE binary against the prefix; this answers it for the wholetree at once, and groups the answer by who needs it, because the consumer decides whether a gapcan ever be reached.
BOTH llvm-nm line shapes have to be handled.
0000000000005c10 T __platform_memset_pattern16 addr, type, name I _memset_pattern4 (indirect for __platform_...) type, name, prose _CGEventTapCreateForPSN undefined: BARE NAME, no type letter
Taking parts[-1] gets the indirect one wrong (it reads the target, so the alias looks undefined).Taking the token after the type letter gets the bare one wrong (it returns nothing, so EVERYundefined symbol disappears and the gap reads zero). Both mistakes were made here; hence theself-check at the bottom, which fails loudly rather than printing a confident number."""import os, subprocess, sys, collectionsNM = "/nix/store/0m6d7ckkm9wl4vbwdkyzicvb3wxm11m4-llvm-22.1.8/bin/llvm-nm"MAGIC = (b"\xcf\xfa\xed\xfe", b"\xce\xfa\xed\xfe", b"\xca\xfe\xba\xbe", b"\xbe\xba\xfe\xca")
def is_macho(p): try: with open(p, "rb") as h: return h.read(4) in MAGIC except OSError: return False
def name_of(line): t = line.split() if not t: return None if len(t) == 1: return t[0] for i, tok in enumerate(t): if len(tok) == 1 and tok.isalpha() and i + 1 < len(t): return t[i + 1] return t[-1]
def syms(p, undef): flag = "--undefined-only" if undef else "--defined-only" try: out = subprocess.run([NM, flag, "--arch=x86_64", p], capture_output=True, text=True, timeout=120).stdout except Exception: return set() return {n for n in (name_of(l) for l in out.splitlines()) if n and n.startswith(("_", "$"))}
assert name_of("0000000000005c10 T __platform_memset_pattern16") == "__platform_memset_pattern16"assert name_of(" I _memset_pattern4 (indirect for __platform_memset_pattern4)") == "_memset_pattern4"assert name_of("_CGEventTapCreateForPSN") == "_CGEventTapCreateForPSN"
root = sys.argv[1]files = [os.path.join(d, n) for d, _, ns in os.walk(root) for n in ns if not os.path.islink(os.path.join(d, n)) and is_macho(os.path.join(d, n))]defined, undefined = set(), collections.defaultdict(set)for p in files: defined |= syms(p, False) for s in syms(p, True): undefined[s].add(p)assert undefined, "no undefined symbols read at all: the parser is broken again"gap = sorted(s for s in undefined if s not in defined)def pyobjc(p): return "/PyObjC/" in p or "Python.framework" in prest = [s for s in gap if not all(pyobjc(p) for p in undefined[s])]print(f"files {len(files)}; undefined names {len(undefined)}; defined names {len(defined)}")print(f"gap {len(gap)}: PyObjC only {len(gap) - len(rest)}, rest {len(rest)}")byfile = collections.Counter()for s in rest: for p in undefined[s]: if not pyobjc(p): byfile[os.path.basename(p)] += 1print("\nwho needs the rest:")for name, n in byfile.most_common(20): print(f" {n:4d} {name}")print("\nnon-Swift, non-Kerberos consumers:")for s in rest: who = [os.path.basename(p) for p in undefined[s] if not pyobjc(p)] if all(("libswift" in w or "Kerberos" in w) for w in who): continue print(f" {s} <- {', '.join(sorted(set(who))[:3])}")