In digging around the code, I asked claude what it would take to emit RPython file/linenumbers instead of the more cryptic generated C file/linenumbers in fatal error tracebacks. Here was the answer:

The change requires three files:

• rpython/translator/exceptiontransform.py

  • Import offset2lineno from rpython.tool.error
  • In gen_exc_check, after identifying spaceop = block.operations[-1], derive the RPython source location:
    • filename from graph.func.__code__.co_filename (with a fallback for graphs without a func)
    • lineno from offset2lineno(graph.func.__code__, spaceop.offset) if spaceop.offset >= 0, else graph.func.__code__.co_firstlineno
  • Attach both as extra attributes on the debug_record_traceback SpaceOperation (e.g. op.rpy_filename, op.rpy_lineno)
  • Same for the second creation site in the except block handler (line ~358), where the relevant location is the graph's first line rather than a specific op offset

• rpython/translator/c/funcgen.py

  • In OP_DEBUG_RECORD_TRACEBACK and OP_DEBUG_CATCH_EXCEPTION, read rpy_filename/rpy_lineno from op (with fallback to current behaviour if absent)
  • Emit the RPython filename and lineno as string/integer literals rather than PYPY_FILE_NAME/__LINE__

• rpython/translator/c/src/debug_traceback.h

  • Change PYPY_DEBUG_RECORD_TRACEBACK(funcname) and PYPY_DEBUG_CATCH_EXCEPTION(funcname, etype, is_fatal) to accept explicit filename and lineno parameters instead of using PYPY_FILE_NAME and
    __LINE__
  • The static struct pypydtpos_s loc initializer changes from { PYPY_FILE_NAME, funcname, __LINE__ } to { filename, funcname, lineno }
  • PYPY_FILE_NAME can then be removed since nothing references it

The result: crash tracebacks show e.g. File "pypy/interpreter/pyframe.py", line 345, in execute_frame instead of File "pypy_interpreter_1.c", line 52934, in execute_frame.