Fix returning from LEAVE to surrounding scope #1785
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patrickbkr
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Discussed in Raku/problem-solving#417 Depends on these three PRs: - MoarVM/MoarVM#1782 - MoarVM/MoarVM#1785 - MoarVM/MoarVM#1788
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I believe this works reliably. So I guess it's ready for review. |
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The general question of what Technically this PR is unreladed to that issue. Can this PR thus be merged? Again, who's best to ping? @MasterDuke17 @niner |
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Discussed in Raku/problem-solving#417 Depends on these three PRs: - MoarVM/MoarVM#1782 - MoarVM/MoarVM#1785 - MoarVM/MoarVM#1788
niner
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May 28, 2024
When a LEAVE phaser is run during an unwind, there is no valid
return_address set in the LEAVE phasers outer frame. (It's return_address is
actually set to interp_cur_op which is still the one that started the unwind
in some unrelated frame.) Thus when a `return` in a LEAVE happens, the
handler of the outer frame is missed, because `search_frame_handlers_lex()`
validates that the `return_address` lies in the handlers area. Luckily
there is a flag set on the LEAVE's outer frame:
MVM_FRAME_FLAG_EXIT_HAND_RUN. We can simply check for that flag and ignore
the frame handlers area. This is fine to do, because frames that have an
exit handler attached can not be inlined. This fixes:
sub s() {
LEAVE return 5;
return 7;
}
s()
which before this fix printed
Attempt to return outside of any Routine
in sub s at leave-bug.raku line 2
in block at leave-bug.raku line 5
Fixes MoarVM#1784
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patrickbkr
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Discussed in Raku/problem-solving#417 Depends on these three PRs: - MoarVM/MoarVM#1782 - MoarVM/MoarVM#1785 - MoarVM/MoarVM#1788
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When a LEAVE phaser is run during an unwind, there is no valid return_address set in the LEAVE phasers caller frame. (It return_address is actually set to cur_op which is still the one that started the unwind in some unrelated frame.) Thus when a
returnin a LEAVE happens, the handler of the outer frame is missed, becausesearch_frame_handlers_lex()validates that thereturn_addresslies in the handlers area. Luckily there is a flag set on the LEAVE's outer frame:MVM_FRAME_FLAG_EXIT_HAND_RUN. We can simply check for that flag and ignore the frame handlers area. This is fine to do, because frames that have an exit handler attached can not be inlined. This fixes:
which before this fix printed
Fixes #1784