1# GDB Python script to handle Cargo `<exe>.trim-paths.jsonl` files from the trim-paths feature2#  - https://github.com/rust-lang/cargo/issues/121373#  - https://github.com/rust-lang/rust/issues/11154045import json6import os7import gdb8import sys91011# https://doc.guix.gnu.org/gdb/16.3/en/html_node/Source-Path.html#index-set-substitute_002dpath12def _process_v1_trim_paths(lines, trim_paths_path):13    for idx, line in enumerate(lines[2:], start=3):14        try:15            entry = json.loads(line)16            if "from" in entry and "to" in entry:17                cmd = f'set substitute-path "{entry["from"]}" "{entry["to"]}"'18                gdb.execute(cmd)19        except json.JSONDecodeError:20            print(21                f"(rust-gdb) warning: invalid JSON on line {idx} of {trim_paths_path}",22                file=sys.stderr,23            )242526def _load_trim_paths(filepath):27    trim_paths_path = f"{filepath}.trim-paths.jsonl"2829    # FIXME: It might be worth looking into the debuginfod fetch content if the local file30    # doesn't exists (maybe with `debuginfod-find debuginfo`).31    if not os.path.isfile(trim_paths_path):32        return3334    try:35        # Load all the lines of the trim-paths file36        with open(trim_paths_path, "r", encoding="utf-8") as f:37            lines = [line.strip() for line in f]3839        # Abort if we have less than 3 lines as that means that we cannot have any40        # substitutions (header + metadata is already 2 lines)41        if not lines or len(lines) < 3:42            return4344        # Try loading the header line, which contains the version (v) field45        try:46            header = json.loads(lines[0])47            ver = header["v"]48        except json.JSONDecodeError:49            print(50                f"(rust-gdb) warning: header line 1 of {trim_paths_path} is not valid JSON",51                file=sys.stderr,52            )53            return5455        # We only handle version 156        if ver == 1:57            _process_v1_trim_paths(lines, trim_paths_path)58        else:59            print(60                f"(rust-gdb) warning: unsupported trim-paths version {ver}: {trim_paths_path}",61                file=sys.stderr,62            )63    except Exception as e:64        print(65            f"(rust-gdb) warning: failed to process trim-paths mappings: {e} of {trim_paths_path}",66            file=sys.stderr,67        )686970def _on_objfile(objfile):71    filepath = objfile.filename7273    if not filepath or not objfile.is_valid() or not os.path.isfile(filepath):74        return7576    _load_trim_paths(filepath)777879def _on_progspace(progspace):80    filepath = progspace.filename8182    if not filepath or not os.path.isfile(filepath):83        return8485    _load_trim_paths(filepath)868788def _on_new_objfile(event):89    _on_objfile(event.new_objfile)909192def _on_executable_changed(event):93    _on_progspace(event.progspace)949596# Setup the events for new objfile (so) and new executable97# https://doc.guix.gnu.org/gdb/16.3/en/html_node/Events-In-Python.html98#99# FIXME: should we handle clear/free events?100gdb.events.new_objfile.connect(_on_new_objfile)101gdb.events.executable_changed.connect(_on_executable_changed)102103# Load the trim-paths files for the already loaded objfiles104for objfile in gdb.objfiles():105    _on_objfile(objfile)