Created
September 8, 2016 13:12
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Compiler segmentation fault in Xcode 8 GM using ExpressibleByArrayLiteral
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| // Save this to stack.swift, then run | |
| // | |
| // $ xcrun swift stack.swift | |
| // | |
| // Does it compile or does the compiler segfault? | |
| struct Stack<Element> { | |
| var elements: [Element] = [] | |
| } | |
| extension Stack: ExpressibleByArrayLiteral { | |
| init(arrayLiteral elements: Element...) { | |
| self.elements = elements | |
| } | |
| } |
Same here:
→ xcrun swift stack.swift
0 swift 0x0000000109cb8b6d PrintStackTraceSignalHandler(void*) + 45
1 swift 0x0000000109cb85b6 SignalHandler(int) + 470
2 libsystem_platform.dylib 0x00007fffa3b15bba _sigtramp + 26
3 libsystem_platform.dylib 0x00007fff58ba1320 _sigtramp + 3037247360
4 swift 0x00000001071968b9 swift::irgen::IRGenFunction::emitTypeMetadataRef(swift::CanType) + 73
5 swift 0x00000001071d407d void llvm::function_ref<void (swift::irgen::GenericRequirement)>::callback_fn<(anonymous namespace)::EmitPolymorphicArguments::emit(swift::CanTypeWrapper<swift::SILFunctionType>, llvm::ArrayRef<swift::Substitution>, swift::irgen::WitnessMetadata*, swift::irgen::Explosion&)::$_14>(long, swift::irgen::GenericRequirement) + 861
6 swift 0x00000001071c99e1 (anonymous namespace)::PolymorphicConvention::enumerateRequirements(llvm::function_ref<void (swift::irgen::GenericRequirement)> const&) + 129
7 swift 0x00000001071d3bdb swift::irgen::emitPolymorphicArguments(swift::irgen::IRGenFunction&, swift::CanTypeWrapper<swift::SILFunctionType>, swift::CanTypeWrapper<swift::SILFunctionType>, llvm::ArrayRef<swift::Substitution>, swift::irgen::WitnessMetadata*, swift::irgen::Explosion&) + 459
8 swift 0x00000001072304f5 (anonymous namespace)::IRGenSILFunction::visitFullApplySite(swift::FullApplySite) + 2997
9 swift 0x000000010721b268 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 9080
10 swift 0x00000001071414d0 swift::irgen::IRGenerator::emitLazyDefinitions() + 5216
11 swift 0x000000010720119b performIRGeneration(swift::IRGenOptions&, swift::ModuleDecl*, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&, swift::SourceFile*, unsigned int) + 1723
12 swift 0x00000001071ff507 swift::performIRGeneration(swift::IRGenOptions&, swift::ModuleDecl*, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&) + 1527
13 swift 0x00000001070e3a7b swift::RunImmediately(swift::CompilerInstance&, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&, swift::IRGenOptions&, swift::SILOptions const&) + 187
14 swift 0x00000001070cf07e performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*) + 23358
15 swift 0x00000001070c7265 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 17029
16 swift 0x000000010708482d main + 8685
17 libdyld.dylib 0x00007fffa3909255 start + 1
Stack dump:
0. Program arguments: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -interpret stack.swift -target x86_64-apple-macosx10.9 -enable-objc-interop -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk -color-diagnostics -module-name stack
1. While emitting IR SIL function @_TFV5stack5StackCft12arrayLiteralGSax__GS0_x_ for 'init' at stack.swift:12:7
Segmentation fault: 11
→ swift --version
Apple Swift version 3.0 (swiftlang-800.0.46.2 clang-800.0.38)
Target: x86_64-apple-macosx10.9
If you need a workaround for the time being, this seems to compile fine:
struct Stack<Element> {
var elements: [Element]
init(elements: [Element]) {
self.elements = elements
}
}
extension Stack: ExpressibleByArrayLiteral {
init(arrayLiteral elements: Element...) {
self.elements = elements
}
}The problem seems to be related to the inline instantiation of the elements array.
@chrisfsampaio Ah, that's interesting, thanks. Another workaround is to explicitly call self.init from the extension:
struct Stack<Element> {
var elements: [Element] = []
}
extension Stack: ExpressibleByArrayLiteral {
init(arrayLiteral elements: Element...) {
self.init(elements: elements)
}
}
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I am seeing this with Xcode 8 GM seed:
Using
DEVELOPMENT-SNAPSHOT-2016-09-07-a, it compiles fine:It also compiles fine with older snapshots, such as
DEVELOPMENT-SNAPSHOT-2016-08-07-a, which is the oldest one I still have installed.