[SR-9108] GSB drops requirements when processing superclass constrained type #51605
Description
| Previous ID | SR-9108 |
| Radar | rdar://44736411 |
| Original Reporter | carlos4242 (JIRA User) |
| Type | Bug |
| Status | Closed |
| Resolution | Done |
Environment
Mac Pro 2013, running macOS 10.13.6.
The swift compiler is the pre-built one from Xcode 10. I will attempt to build swift 4.2 from scratch and confirm that the issue still exists there, that it is not an "Apple" created issue.
It would be really good if someone can confirm if this is a bug in swift 4.2 compiled on a linux box.
Additional Detail from JIRA
| Votes | 0 |
| Component/s | Compiler |
| Labels | Bug, 4.2Regression, CompilerCrash, OptimizedOnly |
| Assignee | @slavapestov |
| Priority | Medium |
md5: ebc0bd91af09edfda7c3156aa2734372
Issue Description:
A regression seems to have appeared in the optimisation pipeline for SIL.
I've got it down to a fairly minimal case...
protocol SimpleProto: class {
init(simpleValue: Int)
}
class BaseClass {
let baseValue: String
required init(baseValue: String) {
self.baseValue = baseValue
print(baseValue)
}
}
extension SimpleProto where Self: BaseClass {
init(simpleValue: Int) {
self.init(baseValue: "***")
}
}
class AdjustedClass: BaseClass, SimpleProto {
// required init(simpleValue: Int) {
// super.init(baseValue: "---")
// }
required init(baseValue: String) {
super.init(baseValue: baseValue)
}
}
print("initialising...")
let viceControlType: SimpleProto.Type = AdjustedClass.self
let control = viceControlType.init(simpleValue: 901)
print("done \(control)")
Compiled with optimisation turned on, this will crash the compile in Xcode 10 [Apple Swift version 4.2 (swiftlang-1000.11.37.1 clang-1000.11.45.1)].
e.g.
...Xcode\ 10.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc -O crashOptimiser.swift
swift 0x000000010be5a64a PrintStackTraceSignalHandler(void*) + 420
swift 0x000000010be5a64a PrintStackTraceSignalHandler(void*) + 421
swift 0x000000010be59dfe SignalHandler(int) + 3022 libsystem_platform.dylib 0x00007fff5b93ff5a _sigtramp + 263 libsystem_platform.dylib 0x00007ffee7b9f580 _sigtramp + 23512981124
swift 0x0000000108fd32b0 (anonymous namespace)::SILTypeSubstituter::substSILFunctionType(swift::CanTypeWrapper<swift::SILFunctionType>) + 14085
swift 0x0000000108c11417 swift::tryDevirtualizeApply(swift::ApplySite, swift::ClassHierarchyAnalysis*, swift::OptRemark::Emitter*) + 35756
swift 0x0000000108da4623 (anonymous namespace)::Devirtualizer::run() + 7397
swift 0x0000000108ccb0c9 swift::SILPassManager::execute() + 39778
swift 0x00000001080edd32 performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 477309
swift 0x00000001080dedc5 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 771710
swift 0x0000000108084a35 main + 134911 libdyld.dylib 0x00007fff5b631015 start + 1
Stack dump:
0. Program arguments: .../Xcode 10.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -c -primary-file crashOptimiser.swift -target x86_64-apple-darwin17.7.0 -enable-objc-interop -O -color-diagnostics -module-name crashOptimiser -o /var/folders/wm/dg7pjp_93gz6y8lgphhwklfjkjnwyt/T/crashOptimiser-a447ff.o
1. While running pass #​3477 SILFunctionTransform "Devirtualizer" on SILFunction "@main".
<unknown>:0: error: unable to execute command: Segmentation fault: 11
<unknown>:0: error: compile command failed due to signal 11 (use -v to see invocation)
If the initialiser is uncommented in AdjustedClass, it compiles fine.
With optimisations turned off it compiles and runs fine:
...Xcode\ 10.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc crashOptimiser.swift
This produces a working, simple program.
Also, I've tested the above command using the Xcode 9.4 version of swift [Apple Swift version 4.1.2 (swiftlang-902.0.54 clang-902.0.39.2)]
With that version, no crash is seen, even if optimisations are turned on, and even if the first initialiser in AdjustedClass is commented out, and the program runs fine and behaves as you would expect (the initialiser in the protocol extension is called).