swift-driver segfaults whenever it can’t find one of its input files

[tayloraswift]

Description

swift-driver segfaults whenever it can’t find one of its input files, and the path does not end in a .swift extension.

Reproduction

$ swiftc this-file-doesnt-exist

Stack dump

💣 Program crashed: Signal 11: Backtracing...

💣 Program crashed: Bad pointer dereference at 0x0000000000000000

Thread 0 "swift-driver" crashed:

 0 0x0000000000000000
 1 (anonymous namespace)::BuildEngineImpl::executeTasks(llbuild::core::KeyType const&) + 11575 in swift-driver at /home/build-user/llbuild/lib/Core/BuildEngine.cpp:1090:14
 2 llbuild::core::BuildEngine::build(llbuild::core::KeyType const&) + 654 in swift-driver at /home/build-user/llbuild/lib/Core/BuildEngine.cpp:1593:20
 3 llb_buildengine_build + 140 in swift-driver at /home/build-user/llbuild/products/libllbuild/Core-C-API.cpp:216:26
 4 specialized Array.withUnsafeBufferPointer<A>(_:) in swift-driver at /home/build-user/llbuild/products/llbuildSwift/CoreBindings.swift:407:39
 5 specialized Key.withInternalDataPtr<A>(closure:) in swift-driver at /home/build-user/llbuild/products/llbuildSwift/CoreBindings.swift:61:21
 6 specialized withUnsafeMutablePointer<A, B>(to:_:) in swift-driver at /home/build-user/llbuild/products/llbuildSwift/CoreBindings.swift:407:17
 7 specialized withUnsafePointer<A, B>(to:_:) in swift-driver at /home/build-user/llbuild/products/llbuildSwift/CoreBindings.swift:105:9
 8 BuildEngine.build(key:) + 60 in swift-driver at /home/build-user/llbuild/products/llbuildSwift/CoreBindings.swift:63:20
 9 specialized LLBuildEngine.build<A>(key:) + 626 in swift-driver at Sources/SwiftDriverExecution/llbuild.swift:97:24
10 MultiJobExecutor.execute(env:fileSystem:) + 215 in swift-driver at /home/build-user/swift-driver/Sources/SwiftDriverExecution/MultiJobExecutor.swift:305:29
11 SwiftDriverExecutor.execute(workload:delegate:numParallelJobs:forceResponseFiles:recordedInputModificationDates:) + 322 in swift-driver at /home/build-user/swift-driver/Sources/SwiftDriverExecution/SwiftDriverExecutor.swift:88:25
12 Driver.performTheBuild(allJobs:jobExecutionDelegate:forceResponseFiles:) + 476 in swift-driver at /home/build-user/swift-driver/Sources/SwiftDriver/Driver/Driver.swift:1495:18
13 Driver.run(jobs:) + 7109 in swift-driver at /home/build-user/swift-driver/Sources/SwiftDriver/Driver/Driver.swift:1434:13
14 swift_driver_main + 2576 in swift-driver at /home/build-user/swift-driver/Sources/swift-driver/main.swift:107:14

Backtrace took 3.36s

Segmentation fault (core dumped)

Expected behavior

swift-driver should not segfault

Environment

$ swiftc --version
Swift version 5.9.2 (swift-5.9.2-RELEASE)
Target: x86_64-unknown-linux-gnu

Additional information

No response