Make a temporary existential when reflecting weak properties #4397
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@swift-ci Please test. |
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@rjmccall Can you review? |
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| // First create a temporary existential. | ||
| auto valueSize = type->getValueWitnesses()->getSize(); | ||
| auto temporaryValue = static_cast<void*>(malloc(valueSize)); |
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It's probably more efficient to use vw_allocBuffer here.
When getting a mirror child that is a class existential, there may be witness tables for the protocol composition to copy. Don't just take the address of a class instance pointer from the stack - make a temporary existential-like before calling into the Mirror constructor. This now correctly covers reflecting weak optional class types, and weak optional class existential types, along with fixing a stack buffer overflow reported by the Address Sanitizer (thanks, ASan!). Tests were also updated to check for the validity of the child's data. rdar://problem/27348445
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@swift-ci Please test. |
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@swift-ci Please test OS X Platform. |
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@swift-ci Smoke test OS X Platform. |
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Smoke test didn't respond, but the full OS X platform test passed, so I'll merge. |
| @@ -2337,11 +2339,15 @@ struct ClassExistentialContainer { | |||
| return reinterpret_cast<const WitnessTable* const *>(this + 1); | |||
| } | |||
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| void copyTypeInto(ClassExistentialContainer *dest, unsigned numTables) const { | |||
| void copyTypeInto(ClassExistentialContainerImpl *dest, | |||
| unsigned numTables) const { | |||
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Minor request (totally unnecessary for 3.0): you could make this templated over the dest's value type, since it doesn't touch that field at all.
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LGTM, thanks! |
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Thanks John! |
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When getting a mirror child that is a class existential, there
may be witness tables for the protocol composition to copy. Don't
just take the address of a class instance pointer from the stack -
make a temporary existential-like before calling into the Mirror
constructor.
This now correctly covers reflecting weak optional class types, and weak
optional class existential types, along with fixing a stack buffer
overflow reported by the Address Sanitizer (thanks, ASan!).
Tests were also updated to check for the validity of the child's data.
rdar://problem/27348445