Jonas Devlieghere
119e576302
With LLDB_ENABLE_DYNAMIC_SCRIPTINTERPRETERS, the script interpreter plugins are built as standalone shared libraries that resolve their lldb_private/llvm references through liblldb's re-exports. liblldb was falling back to liblldb-private.exports, which allowlists the lldb_private/llvm namespaces wholesale. Generate the export list per build instead. For each plugin, run llvm-nm on its compiled objects, keep undefined references in namespaces liblldb owns, subtract the plugin's own definitions, and concatenate the per-plugin lists with liblldb.exports. The plugin's SHARED target LINK_LIBS liblldb, which makes the plugin's compile order depend on liblldb. Wiring the exports file in via add_llvm_symbol_exports' built-in target dependency would form a cycle through that order-only edge. Add NO_TARGET_DEPENDENCY to add_llvm_symbol_exports so we can apply the file via LINK_DEPENDS alone; that still triggers a relink when the symbol set changes, without participating in compile-order tracking. Windows is unchanged: msvc_extract_private_symbols.py was already doing per-symbol extraction at namespace granularity. Assisted-by: Claude
101 lines
2.7 KiB
Python
101 lines
2.7 KiB
Python
"""Emit the LLDB-side imports of a script interpreter plugin's objects.
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The result is fed into liblldb's exports file so the dynamic loader can
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satisfy the plugin's references at runtime without growing liblldb's
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re-export surface beyond what the plugin actually consumes.
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"""
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import argparse
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import subprocess
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import sys
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# Mangled-name prefixes liblldb owns. Symbols outside these namespaces
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# are resolved through other libraries on the loader path.
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EXPORT_PREFIXES = (
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"_ZN12lldb_private",
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"_ZNK12lldb_private",
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"_ZTVN12lldb_private",
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"_ZTSN12lldb_private",
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"_ZTIN12lldb_private",
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"_ZN4lldb",
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"_ZNK4lldb",
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"_ZTVN4lldb",
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"_ZTSN4lldb",
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"_ZTIN4lldb",
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"_ZN4llvm",
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"_ZNK4llvm",
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"_ZTVN4llvm",
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"_ZTSN4llvm",
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"_ZTIN4llvm",
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)
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def normalize(sym, mach_o):
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# Mach-O reports an extra leading underscore that the .exports file
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# format does not carry.
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if mach_o and sym.startswith("_"):
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return sym[1:]
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return sym
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def collect(nm, obj, mach_o):
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"""Return (undefined, defined) symbol-name sets for `obj`.
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Both halves are needed so cross-object references that the plugin's
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own objects satisfy can be subtracted before emitting.
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"""
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undefined = set()
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defined = set()
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out = subprocess.check_output(
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[nm, "--undefined-only", "--just-symbol-name", obj], text=True
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)
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for line in out.splitlines():
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sym = line.strip()
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if sym:
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undefined.add(normalize(sym, mach_o))
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out = subprocess.check_output(
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[nm, "--defined-only", "--extern-only", "--just-symbol-name", obj],
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text=True,
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)
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for line in out.splitlines():
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sym = line.strip()
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if sym:
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defined.add(normalize(sym, mach_o))
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return undefined, defined
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def main():
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument("--nm", required=True, help="Path to llvm-nm.")
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parser.add_argument("-o", "--output", required=True, help="Output exports file.")
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parser.add_argument(
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"--mach-o",
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action="store_true",
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help="Strip the leading underscore Mach-O prepends to every symbol.",
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)
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parser.add_argument(
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"objects", nargs="+", help="Object files (or archives) to scan."
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)
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args = parser.parse_args()
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undefined = set()
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defined = set()
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for obj in args.objects:
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u, d = collect(args.nm, obj, args.mach_o)
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undefined.update(u)
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defined.update(d)
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syms = {s for s in (undefined - defined) if s.startswith(EXPORT_PREFIXES)}
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with open(args.output, "w", newline="\n") as f:
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for s in sorted(syms):
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f.write(s + "\n")
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if __name__ == "__main__":
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sys.exit(main())
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