Function selection via index broken on v0.2.24 to v0.2.28

[zeroflaw]

I updated to v0.2.28 and had an issue selecting a function. So I had this list :

cargo asm -p exchange_reactor --lib 

 0 "<exchange_reactor::BootstrapReactor as exchange_reactor::Reactor>::poll" [19]
 1 "<exchange_reactor::BootstrapReactor as exchange_reactor::Reactor>::state" [8]
 2 "<exchange_reactor::BootstrapReactor as exchange_reactor::ReactorCold<exchange_reactor::TradingReactor>>::next" [29]
 3 "<exchange_reactor::CompleteReactor as exchange_reactor::Reactor>::poll" [7]
 4 "<exchange_reactor::CompleteReactor as exchange_reactor::Reactor>::state" [7]
 5 "<exchange_reactor::CompleteReactor as exchange_reactor::ReactorCold<exchange_reactor::TradingReactor>>::next" [14]
 6 "<exchange_reactor::ShutdownReactor as exchange_reactor::Reactor>::poll" [19]
 7 "<exchange_reactor::ShutdownReactor as exchange_reactor::Reactor>::state" [8]
 8 "<exchange_reactor::ShutdownReactor as exchange_reactor::ReactorCold<exchange_reactor::TradingReactor>>::next" [83]
 9 "<exchange_reactor::TradingReactor as exchange_reactor::ReactorHot>::next" [49]
10 "<exchange_reactor::TradingRuntime as core::default::Default>::default" [48]
11 "core::ptr::drop_in_place<exchange_reactor::BootstrapReactor>" [6]
12 "core::ptr::drop_in_place<exchange_reactor::CompleteReactor>" [7]
13 "core::ptr::drop_in_place<exchange_reactor::ShutdownReactor>" [6]
14 "exchange_reactor::TradingRuntime::cold_handle" [113]
15 "exchange_reactor::TradingRuntime::new" [50]
16 "exchange_reactor::TradingRuntime::next" [92]
17 "exchange_reactor::TradingRuntime::poll" [87]
18 "exchange_reactor::TradingRuntime::poll::cold" [48]
19 "exchange_reactor::cold_log_error" [66]

I then went to select poll of TradingRuntime using

cargo asm -p exchange_reactor --lib 17

I ended up getting the wrong function being exported:

.section ".text.<exchange_reactor::BootstrapReactor as exchange_reactor::Reactor>::poll","ax",@progbits
        .p2align        4, 0x90
        .type   <exchange_reactor::BootstrapReactor as exchange_reactor::Reactor>::poll,@function
<exchange_reactor::BootstrapReactor as exchange_reactor::Reactor>::poll:
---snip---

rolled back through v0.2.28, v0.2.27, v0.2.26, v0.2.25, v0.2.24, which all suffer from the same issue, with v0.2.23 working as expected. My library is not open-source. The poll function is a trait that is implemented on multiple types. Maybe because they have the same name they are getting confused?

If you struggle to reproduce, I am happy to try to create a minimum example.

[zeroflaw]

fyi it broke on commit 74d69ad I am able to get the correct output if I specify the name e.g.

cargo asm -p exchange_reactor --lib exchange_reactor::TradingRuntime::poll 0

[pacak]

Looking. FWIW one of the easier ways to find exactly which commit breaks the code is using git bisect

[pacak]

I pushed rc-0.2.29 branch, with the fix. You can you confirm the bug is gone for you?

[zeroflaw]

Can confirm branch works as expected. Thanks for the quick fix.

[pacak]

Released 0.2.29

[pacak]

Thank you for the bugreport :heart: