[SR-15441] segmentation fault when invoking swift

[swift-ci]

Previous ID	SR-15441
Radar	None
Original Reporter	phil_g (JIRA User)
Type	Bug

Attachment: Download

Environment

ProductName: macOS
ProductVersion: 12.0.1
BuildVersion: 21A559
swift-driver version: 1.26.18 Apple Swift version 5.5.2 (swiftlang-1300.0.40.106 clang-1300.0.29.21)
Target: arm64-apple-macosx12.0

Additional Detail from JIRA

Votes	0
Component/s
Labels	Bug
Assignee	None
Priority	Medium

md5: 88742eff364040feb2aaef91ecaec8b5

Issue Description:

I start swift from the command line giving test.swift as parameter.

> swift test.swift

I would expect that the compiler would warn me that 'a' is not initialized.

Instead a "[1] 73957 segmentation fault swift test.swift" happens, a backtrace is dumped.

test.swift:

func foo() {
    a.first
}
foo()
let a = [1] 

[swift-ci]

Comment by Berik Visschers (JIRA)

Reproduced on M1, swift 5.5.1

Downloads/test.swift:2:7: warning: expression of type 'Int?' is unusedDownloads/test.swift:2:7: warning: expression of type 'Int?' is unused    a.first    ~~^~~~~Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the project and the crash backtrace.Stack dump:0. Program arguments: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-frontend -frontend -interpret Downloads/test.swift -Xllvm -aarch64-use-tbi -enable-objc-interop -stack-check -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.0.sdk -color-diagnostics -new-driver-path /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-driver -resource-dir /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift -module-name test -target-sdk-version 12.0.01. Apple Swift version 5.5.1 (swiftlang-1300.0.31.4 clang-1300.0.29.6)2.3. While running user code "Downloads/test.swift"Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):0  swift-frontend           0x0000000107188534 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 561  swift-frontend           0x000000010718763c llvm::sys::RunSignalHandlers() + 1282  swift-frontend           0x0000000107188b74 SignalHandler(int) + 2923  libsystem_platform.dylib 0x0000000190b344e4 _sigtramp + 564  libswiftCore.dylib       0x000000019db9d40c $sSa5countSivg + 565  libswiftCore.dylib       0x000000019db9f8b4 $sSayxGSlsSl8endIndex0B0QzvgTW + 366  libswiftCore.dylib       0x000000019dbba4a4 $sSlsE5first7ElementQzSgvg + 2807  libswiftCore.dylib       0x000000010a49c0a0 $sSlsE5first7ElementQzSgvg + 184467440712358372048  libswiftCore.dylib       0x000000010a49c010 $sSlsE5first7ElementQzSgvg + 184467440712358370609  swift-frontend           0x0000000102fdd59c llvm::orc::runAsMain(int (*)(int, char**), llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, llvm::Optional<llvm::StringRef>) + 112010 swift-frontend           0x0000000102f57a80 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 const&, swift::SILOptions const&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >&&) + 980811 swift-frontend           0x0000000102f1e6a4 performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 234012 swift-frontend           0x0000000102f11b8c swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 705213 swift-frontend           0x0000000102e6c2d4 main + 93214 dyld                     0x00000001095850f4 start + 520[1]    41321 segmentation fault  swift Downloads/test.swift