I'm using a compiler based on swift 5.1.5 (built from tag swift-5.1.5-RELEASE) and attempting to build my own simple, cut down standard library (for use on bare metal microcontrollers).
It's going OK, but I keep getting segfaults when compiling the code for UnsafeMutableBufferPointer etc.
Here's an example backtrace...
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x8)
* frame #0: 0x000000010001cddc swift`swift::TypeBase::isCanonical(this=0x0000000000000000) const at Types.h:432:51
frame #1: 0x00000001022dd919 swift`swift::TypeBase::getCanonicalType(this=0x0000000000000000) const at Types.h:445:9
frame #2: 0x00000001027df59e swift`swift::TypeBase::isEqual(this=0x00000001202b3cb8, Other=Type @ 0x00007ffeefbf5ea8) at Type.cpp:125:52
frame #3: 0x00000001017d5713 swift`swift::constraints::ConstraintSystem::matchTypes(this=0x00007ffeefbf9a30, type1=Type @ 0x00007ffeefbf6ab8, type2=Type @ 0x00007ffeefbf6ab0, kind=ArgumentConversion, flags=(Storage = 1), locator=ConstraintLocatorBuilder @ 0x00007ffeefbf6fb0) at CSSimplify.cpp:2995:28
frame #4: 0x00000001017f150a swift`swift::constraints::ConstraintSystem::addConstraintImpl(this=0x00007ffeefbf9a30, kind=ArgumentConversion, first=Type @ 0x00007ffeefbf7178, second=Type @ 0x00007ffeefbf7170, locator=ConstraintLocatorBuilder @ 0x00007ffeefbf7360, isFavored=false) at CSSimplify.cpp:6883:12
frame #5: 0x00000001017d1e9c swift`swift::constraints::ConstraintSystem::addConstraint(this=0x00007ffeefbf9a30, kind=ArgumentConversion, first=Type @ 0x00007ffeefbf73e0, second=Type @ 0x00007ffeefbf73d8, locator=ConstraintLocatorBuilder @ 0x00007ffeefbf7430, isFavored=false) at CSSimplify.cpp:7080:11
frame #6: 0x00000001017d0855 swift`swift::constraints::matchCallArguments(cs=0x00007ffeefbf9a30, args=ArrayRef<swift::AnyFunctionType::Param> @ 0x00007ffeefbf7810, params=ArrayRef<swift::AnyFunctionType::Param> @ 0x00007ffeefbf7800, locator=ConstraintLocatorBuilder @ 0x00007ffeefbf79c0) at CSSimplify.cpp:1010:10
frame #7: 0x00000001017ed2b2 swift`swift::constraints::ConstraintSystem::simplifyApplicableFnConstraint(this=0x00007ffeefbf9a30, type1=Type @ 0x00007ffeefbf7c28, type2=Type @ 0x00007ffeefbf7c20, flags=(Storage = 1), locator=ConstraintLocatorBuilder @ 0x00007ffeefbf7d90) at CSSimplify.cpp:5977:9
frame #8: 0x00000001017f16ff swift`swift::constraints::ConstraintSystem::addConstraintImpl(this=0x00007ffeefbf9a30, kind=ApplicableFunction, first=Type @ 0x00007ffeefbf7f58, second=Type @ 0x00007ffeefbf7f50, locator=ConstraintLocatorBuilder @ 0x00007ffeefbf8140, isFavored=false) at CSSimplify.cpp:6893:12
frame #9: 0x00000001017d1e9c swift`swift::constraints::ConstraintSystem::addConstraint(this=0x00007ffeefbf9a30, kind=ApplicableFunction, first=Type @ 0x00007ffeefbf81c0, second=Type @ 0x00007ffeefbf81b8, locator=ConstraintLocatorBuilder @ 0x00007ffeefbf8210, isFavored=false) at CSSimplify.cpp:7080:11
frame #10: 0x00000001017ae3c4 swift`(anonymous namespace)::ConstraintGenerator::visitApplyExpr(this=0x00007ffeefbf8920, expr=0x000000012007df78) at CSGen.cpp:2474:10
frame #11: 0x00000001017a4518 swift`swift::ASTVisitor<(anonymous namespace)::ConstraintGenerator, swift::Type, void, void, void, void, void>::visitCallExpr(this=0x00007ffeefbf8920, E=0x000000012007df78) at ExprNodes.def:135:3
frame #12: 0x000000010179dbf0 swift`swift::ASTVisitor<(anonymous namespace)::ConstraintGenerator, swift::Type, void, void, void, void, void>::visit(this=0x00007ffeefbf8920, E=0x000000012007df78) at ExprNodes.def:135:3
frame #13: 0x000000010179d3d5 swift`(anonymous namespace)::ConstraintWalker::walkToExprPost(this=0x00007ffeefbf8900, expr=0x000000012007df78) at CSGen.cpp:3529:26
frame #14: 0x0000000102485ed0 swift`(anonymous namespace)::Traversal::doIt(this=0x00007ffeefbf88a8, E=0x000000012007df78) at ASTWalker.cpp:1178:23
frame #15: 0x0000000102488750 swift`(anonymous namespace)::Traversal::visitRebindSelfInConstructorExpr(this=0x00007ffeefbf88a8, E=0x00000001202984a0) at ASTWalker.cpp:876:17
frame #16: 0x0000000102486b12 swift`swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(this=0x00007ffeefbf88a8, E=0x00000001202984a0) at ExprNodes.def:127:1
frame #17: 0x0000000102486586 swift`(anonymous namespace)::Traversal::visit(this=0x00007ffeefbf88a8, E=0x00000001202984a0) at ASTWalker.cpp:98:23
frame #18: 0x0000000102485ead swift`(anonymous namespace)::Traversal::doIt(this=0x00007ffeefbf88a8, E=0x00000001202984a0) at ASTWalker.cpp:1175:9
frame #19: 0x0000000102485e10 swift`swift::Expr::walk(this=0x00000001202984a0, walker=0x00007ffeefbf8900) at ASTWalker.cpp:1834:28
frame #20: 0x00000001017964a0 swift`swift::constraints::ConstraintSystem::generateConstraints(this=0x00007ffeefbf9a30, expr=0x00000001202984a0, dc=0x0000000000000000) at CSGen.cpp:3616:24
frame #21: 0x000000010181b868 swift`swift::constraints::ConstraintSystem::solveImpl(this=0x00007ffeefbf9a30, expr=0x00007ffeefbfa458, convertType=Type @ 0x00007ffeefbf8be8, listener=0x00007ffeefbfa248, solutions=0x00007ffeefbf8e88, allowFreeTypeVariables=Disallow) at CSSolver.cpp:1160:28
frame #22: 0x000000010181b294 swift`swift::constraints::ConstraintSystem::solve(this=0x00007ffeefbf9a30, expr=0x00007ffeefbfa458, convertType=Type @ 0x00007ffeefbf8d10, listener=0x00007ffeefbfa248, solutions=0x00007ffeefbf8e88, allowFreeTypeVariables=Disallow) at CSSolver.cpp:1080:19
frame #23: 0x0000000101a96711 swift`swift::TypeChecker::typeCheckExpressionImpl(this=0x000000011f81d010, expr=0x00007ffeefbfa458, dc=0x000000012007d918, convertType=TypeLoc @ 0x00007ffeefbf99e0, convertTypePurpose=CTP_Unused, options=(Storage = 33), listener=0x00007ffeefbfa248, baseCS=0x0000000000000000) at TypeCheckConstraints.cpp:2247:10
frame #24: 0x0000000101a95f47 swift`swift::TypeChecker::typeCheckExpression(this=0x000000011f81d010, expr=0x00007ffeefbfa458, dc=0x000000012007d918, convertType=TypeLoc @ 0x00007ffeefbfa290, convertTypePurpose=CTP_Unused, options=(Storage = 33), listener=0x0000000000000000, baseCS=0x0000000000000000) at TypeCheckConstraints.cpp:2166:10
frame #25: 0x0000000101c87289 swift`(anonymous namespace)::StmtChecker::visitBraceStmt(this=0x00007ffeefbfa948, BS=0x00000001202b3c48) at TypeCheckStmt.cpp:1765:14
frame #26: 0x0000000101c86b7c swift`swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(this=0x00007ffeefbfa948, S=0x00000001202b3c48) at StmtNodes.def:47:1
frame #27: 0x0000000101c80185 swift`bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::BraceStmt>(this=0x00007ffeefbfa948, S=0x00007ffeefbfa900) at TypeCheckStmt.cpp:415:39
frame #28: 0x0000000101c7f07f swift`(anonymous namespace)::StmtChecker::typeCheckBody(this=0x00007ffeefbfa948, S=0x00007ffeefbfa900) at TypeCheckStmt.cpp:425:21
frame #29: 0x0000000101c7e427 swift`swift::TypeChecker::typeCheckConstructorBodyUntil(this=0x000000011f81d010, ctor=0x000000012007d900, EndTypeCheckLoc=SourceLoc @ 0x00007ffeefbfa918) at TypeCheckStmt.cpp:2139:22
frame #30: 0x0000000101c7dc89 swift`swift::TypeChecker::typeCheckAbstractFunctionBodyUntil(this=0x000000011f81d010, AFD=0x000000012007d900, EndTypeCheckLoc=SourceLoc @ 0x00007ffeefbfaa40) at TypeCheckStmt.cpp:1919:12
frame #31: 0x0000000101c7edca swift`swift::TypeChecker::typeCheckAbstractFunctionBody(this=0x000000011f81d010, AFD=0x000000012007d900) at TypeCheckStmt.cpp:1944:16
frame #32: 0x0000000101cd7779 swift`typeCheckFunctionsAndExternalDecls(SF=0x0000000120057300, TC=0x000000011f81d010) at TypeChecker.cpp:323:10
frame #33: 0x0000000101cd8735 swift`swift::performTypeChecking(SF=0x0000000120057300, TLC=0x00007ffeefbfb470, Options=(Storage = 0), StartElem=0, WarnLongFunctionBodies=0, WarnLongExpressionTypeChecking=0, ExpressionTimeoutThreshold=0, SwitchCheckingInvocationThreshold=0) at TypeChecker.cpp:534:5
frame #34: 0x00000001006f1900 swift`swift::CompilerInstance::parseAndCheckTypesUpTo(this=0x00007ffeefbfb278, SF=0x0000000120057300)::$_1::operator()(swift::SourceFile&) const at Frontend.cpp:823:5
frame #35: 0x00000001006f1860 swift`void llvm::function_ref<void (swift::SourceFile&)>::callback_fn<swift::CompilerInstance::parseAndCheckTypesUpTo(callable=140732920738424, params=0x0000000120057300)::$_1>(long, swift::SourceFile&) at STLExtras.h:120:12
frame #36: 0x00000001006dc78c swift`llvm::function_ref<void (swift::SourceFile&)>::operator(this=0x00007ffeefbfb200, params=0x0000000120057300)(swift::SourceFile&) const at STLExtras.h:137:12
frame #37: 0x00000001006dbed1 swift`swift::CompilerInstance::forEachFileToTypeCheck(this=0x0000000121005e00, fn=function_ref<void (swift::SourceFile &)> @ 0x00007ffeefbfb200)>) at Frontend.cpp:1001:7
frame #38: 0x00000001006d9dc4 swift`swift::CompilerInstance::parseAndCheckTypesUpTo(this=0x0000000121005e00, implicitImports=0x00007ffeefbfb4f0, limitStage=TypeChecked) at Frontend.cpp:822:3
frame #39: 0x00000001006d8ed8 swift`swift::CompilerInstance::performSemaUpTo(this=0x0000000121005e00, LimitStage=TypeChecked) at Frontend.cpp:667:3
frame #40: 0x00000001006d8f3a swift`swift::CompilerInstance::performSema(this=0x0000000121005e00) at Frontend.cpp:624:3
frame #41: 0x000000010011ac8e swift`performCompile(Instance=0x0000000121005e00, Invocation=0x00007ffeefbfbee8, Args=ArrayRef<const char *> @ 0x00007ffeefbfbaa0, ReturnValue=0x00007ffeefbfbc1c, observer=0x0000000000000000, Stats=0x0000000000000000) at FrontendTool.cpp:998:14
frame #42: 0x0000000100119c6a swift`swift::performFrontend(Args=ArrayRef<const char *> @ 0x00007ffeefbfbe58, Argv0="/Users/carlpeto/avr-swift/build/Ninja-DebugAssert/swift-macosx-x86_64/bin/swift", MainAddr=0x0000000100002350, observer=0x0000000000000000) at FrontendTool.cpp:1819:5
frame #43: 0x0000000100004520 swift`run_driver(ExecName=(Data = "swift", Length = 5), argv=const llvm::ArrayRef<const char *> @ 0x00007ffeefbfcd00) at driver.cpp:125:14
frame #44: 0x0000000100002e1f swift`main(argc_=53, argv_=0x00007ffeefbff3a0) at driver.cpp:270:12
frame #45: 0x00007fff752ac3d5 libdyld.dylib`start + 1
(lldb) fr s 15
frame #15: 0x0000000102488750 swift`(anonymous namespace)::Traversal::visitRebindSelfInConstructorExpr(this=0x00007ffeefbf88a8, E=0x00000001202984a0) at ASTWalker.cpp:876:17
861 Expr *visitArrowExpr(ArrowExpr *E) {
862 if (Expr *Args = E->getArgsExpr()) {
863 Args = doIt(Args);
864 if (!Args) return nullptr;
865 E->setArgsExpr(Args);
866 }
867 if (Expr *Result = E->getResultExpr()) {
868 Result = doIt(Result);
869 if (!Result) return nullptr;
870 E->setResultExpr(Result);
871 }
872 return E;
873 }
874
875 Expr *visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *E) {
-> 876 Expr *Sub = doIt(E->getSubExpr());
877 if (!Sub) return nullptr;
878 E->setSubExpr(Sub);
879
880 return E;
881 }
882
883 Expr *visitAssignExpr(AssignExpr *AE) {
884 if (Expr *Dest = AE->getDest()) {
885 if (!(Dest = doIt(Dest)))
886 return nullptr;
887 AE->setDest(Dest);
888 }
889
890 if (Expr *Src = AE->getSrc()) {
891 if (!(Src = doIt(AE->getSrc())))
(lldb) e E->dump()
(rebind_self_in_constructor_expr implicit type='()' location=UnsafeBufferPointer.swift:951:10 range=[UnsafeBufferPointer.swift:951:5 - line:951:46]
(call_expr type='<null>' arg_labels=start:count:
(unresolved_dot_expr type='<null>' field 'init' function_ref=single
(declref_expr type='<null>' decl=Swift.(file).UnsafeBufferPointer extension.init(rebasing:).self@UnsafeBufferPointer.swift:949:10 function_ref=unapplied))
(tuple_expr type='<null>' names=start,count
(declref_expr type='<null>' decl=Swift.(file).UnsafeBufferPointer extension.init(rebasing:).base@UnsafeBufferPointer.swift:950:9 function_ref=unapplied)
(unresolved_dot_expr type='<null>' field 'count' function_ref=unapplied
(declref_expr type='<null>' decl=Swift.(file).UnsafeBufferPointer extension.init(rebasing:).slice@UnsafeBufferPointer.swift:949:24 function_ref=unapplied)))))
(lldb)
It looks like this is the code it is attempting to digest...
extension UnsafeBufferPointer {
...
@inlinable // unsafe-performance
public init(rebasing slice: Slice<UnsafeMutableBufferPointer<Element>>) {
let base = slice.base.baseAddress?.advanced(by: slice.startIndex)
self.init(start: base, count: slice.count)
}
I have stripped out most of the stdlib and added it back to my compile a bit at a time so it's likely that functions, types, etc. are missing but it should cause a well formed error rather than a compiler crash.
My guess is that the compiler is unable to compile this code due to an error, a missing type, etc. but the problem is not trapped because compiling a custom standard library module is such an unusual thing to do.
Can anyone give advice how to start figuring out what the real underlying problem is or, if it's a genuine bug in this version of the compiler, how to track down the bug please?
