How do I find out which info table a continuation belongs to?

Ömer Sinan Ağacan omeragacan at
Sun Feb 10 07:49:06 UTC 2019

I'm currently working on a bug and one of the things I often want to know is
what's on the stack. The problem is I can't see labels of continuations so the
information is really useless. Example:

    >>> call printStack(((StgTSO*)0x42000e0198)->stackobj)
    0x42000c8788: RET_SMALL (0x512d70)
    0x42000c8790: RET_SMALL (0x40edf0)
       stk[5] (0x42000c8798) = 0x7b3938
    0x42000c87a0: CATCH_FRAME(0x735a98,0x7d3ff2)
    0x42000c87b8: STOP_FRAME(0x7311b8)

(I modified the printer to print stack locations when printing stacks)

Here I need to know which info table the RET_SMALLs return to. Normally I do
this for other kinds of closures:

    >>> print ((StgClosure*)...)->
    $15 = (const StgInfoTable *) 0x404dc0 <Main_nats_info>

But for continuations that doesn't work:

    >>> print ((StgClosure*)0x42000c8788)->
    $11 = (const StgInfoTable *) 0x512d80
    >>> info symbol 0x512d80
    No symbol matches 0x512d80.

Anyone know how to make this work? Can I maybe mark the continuations label in
the generated assembly somehow to make those labels available in gdb?



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