[OpenMP][OMPT] Fix device identifier collision during callbacks #65595
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Fixes: llvm#65104 When a user assigns devices to target regions it may happen that different identifiers will map onto the same id within different plugins. This will lead to situations where callbacks will become much harder to read, as ambiguous identifiers are reported. We fix this by collecting the index-offset upon general RTL initialization. Which in turn, allows to calculate the unique, user-observable device id.
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This might not be the optimal solution, but somehow we have to propagate the offset value during RTL init. |
| /// Offset which when added to a DeviceId will yield a unique, user-observable | ||
| /// device identifier. |
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Should this be reworded in the sense that makes it clear that this is (mainly/only?) in scenarios with multiple different supported devices?
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Valid point, I'm not pushing that naming or description.
Could also be name the corresponding variable PluginDeviceStartIndex (or similar); "global" was my go-to as a globally / unique DeviceId we wanted to determine.
Or was your initial thought that a clarification in the comment would suffice?
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Valid point, I'm not pushing that naming or description.
Could also be name the corresponding variable PluginDeviceStartIndex (or similar); "global" was my go-to as a globally / unique DeviceId we wanted to determine. Or was your initial thought that a clarification in the comment would suffice?
I like PluginDeviceStartIndex because that partially corresponds to the variable name where it originates from (libomptarget rtl.cpp).
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Since we are in the GenericPluginTy namespace, I'll drop the Plugin prefix and suggest: DeviceIdStartIndex.
Also go with a more verbose description as JP suggested -- so it should be more clear when this is actually useful.
…#65595) Fixes: llvm#65104 When a user assigns devices to target regions it may happen that different identifiers will map onto the same id within different plugins. This will lead to situations where callbacks will become much harder to read, as ambiguous identifiers are reported. We fix this by collecting the index-offset upon general RTL initialization. Which in turn, allows to calculate the unique, user-observable device id.
Fixes: #65104
When a user assigns devices to target regions it may happen that different identifiers will map onto the same id within different plugins. This will lead to situations where callbacks will become much harder to read, as ambiguous identifiers are reported.
We fix this by collecting the index-offset upon general RTL initialization. Which in turn, allows to calculate the unique, user-observable device id.