SILGen: Fix 'multiple definitions of symbol' error for functions with @_backDeploy containing defer blocks
#62444
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… `@_backDeploy` containing defer blocks. If the emission of a function is delayed via `emitOrDelayFunction()`, then the function is recorded on a list of delayed functions. If the delayed function is later referenced, then the function moves from the delayed list to the "forced" list which will cause it to actually be emitted later. The implementation of `emitOrDelayFunction()` had a bug when called twice for the same delayable function - it would emit that function prematurely if the function moved to the forced list between the two invocations. Later, during forced function emission a multiple definitions of symbol diagnostic would be emitted since the function was not empty. This issue could be triggered by `@_backDeploy` functions that have auxilary delayable helper functions (e.g. defer blocks). SILGen visits `@_backDeploy` functions twice (once for the copy of the function emitted into the client and once for the resilient copy of the function) so `emitOrDelayFunction()` is called twice for each of the helper functions and the helper functions could become referenced between the two calls. The fix is to check for an existing entry in the forced functions list before delaying or emitting a delayable function. Resolves rdar://102909684
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Older versions of the 5.8 compiler have a bug when generating SIL for functions with `@_backDeploy` containing defer blocks (swiftlang#62444) and for now we need the standard library interface to be compatible with those older compilers. Resolves rdar://104045168
tshortli
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…tandard library. Older versions of the 5.8 compiler have a bug when generating SIL for functions with `@_backDeploy` containing defer blocks (swiftlang#62444) and for now we need the standard library interface to be compatible with those older compilers. Resolves rdar://104045168
tshortli
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Jan 10, 2023
…tandard library. Older versions of the 5.8 compiler have a bug when generating SIL for functions with `@_backDeploy` containing defer blocks (swiftlang#62444) and for now we need the standard library interface to be compatible with those older compilers. Resolves rdar://104045168
This was referenced Jan 10, 2023
tshortli
added a commit
to tshortli/swift
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this pull request
Jan 10, 2023
…tandard library. Older versions of the 5.8 compiler have a bug when generating SIL for functions with `@_backDeploy` containing defer blocks (swiftlang#62444) and for now we need the standard library interface to be compatible with those older compilers. Resolves rdar://104045168
tshortli
added a commit
to tshortli/swift
that referenced
this pull request
Jan 10, 2023
…tandard library. Older versions of the 5.8 compiler have a bug when generating SIL for functions with `@_backDeploy` containing defer blocks (swiftlang#62444) and for now we need the standard library interface to be compatible with those older compilers. Resolves rdar://104045168
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If the emission of a function is delayed via
emitOrDelayFunction(), then the function is recorded on a list of delayed functions. If the delayed function is later referenced, then the function moves from the delayed list to the "forced" list which will cause it to actually be emitted later. The implementation ofemitOrDelayFunction()had a bug when called twice for the same delayable function - it would emit that function prematurely if the function moved to the forced list between the two invocations. Later, during forced function emission a multiple definitions of symbol diagnostic would be emitted since the function was not empty.This issue could be triggered by
@_backDeployfunctions that have auxilary delayable helper functions (e.g. defer blocks). SILGen visits@_backDeployfunctions twice (once for the copy of the function emitted into the client and once for the resilient copy of the function) soemitOrDelayFunction()is called twice for each of the helper functions and the helper functions could become referenced between the two calls.The fix is to check for an existing entry in the forced functions list before delaying or emitting a delayable function.
Resolves rdar://102909684