https://bugs.kde.org/show_bug.cgi?id=464198
Bug ID: 464198
Summary: KDevelop parses deeply nested template aliases for an
extremely long time (indefinitely)
Classification: Applications
Product: kdevelop
Version: 5.10.221201
Platform: Compiled Sources
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Language Support: CPP (Clang-based)
Assignee: kdevelop-bugs-n...@kde.org
Reporter: igor...@gmail.com
Target Milestone: ---
Created attachment 155239
--> https://bugs.kde.org/attachment.cgi?id=155239&action=edit
The slowly-parsed test file from the LLVM repository
SUMMARY
I have tried working on the LLVM project in KDevelop. Sometimes KDevelop
crashes. Very often KDevelop freezes on exit. I traced the freeze to indefinite
parsing of the file
https://github.com/llvm/llvm-project/blob/main/clang/test/CodeGenCXX/mangle-ms-back-references-pr13207.cpp
(attached). The line `using A8 = Fooob<A7, A7, A7, A7, A7, A7, A7, A7, A7,
A7>;` , along with the previous similar nested aliases for A7, A6, ... A0,
gives KDevelop too much work. If it gets to the next two aliases, A9 and A10,
the parsing can probably take days or months.
A likely culprit is Visitor::createClassTemplateSpecializationType(). There are
several nested GDB frames at the line
kdevelop/plugins/clang/duchain/builder.cpp:766: `currentType =
makeType(argumentType, typeDecl);`. Either this implementation should be
greatly optimized or KDevelop should detect such long parsing and give it up.
The LLVM test's express purpose is to test Clang's performance, according to a
comment below:
// This should take milliseconds, not minutes.
void f(A9 a) {}
I guess KDevelop's attempt to parse the code more comprehensively backfires in
this case. When I removed this test file from the llvm repository, KDevelop's
parser froze again with a very similar backtrace. Unfortunately, the value of
the tStr variable (clang_getTypeSpelling) cannot be found in the llvm
repository, and so the other slowly-parsed file is not so easy to locate. The
code must be generated somehow, maybe from variadic templates. A workaround
that I hope will prevent background parser freezes is to exclude the
"/clang/test/*/" pattern in the Project Filter.
STEPS TO REPRODUCE
1. Download the attached file.
2. Open it in KDevelop.
3. Try to exit KDevelop.
OBSERVED RESULT
2. After the second step KDevelop's Background Parser keeps a CPU core busy
indefinitely.
3. After the third step KDevelop does not exit, but keeps parsing the vexing
file.
EXPECTED RESULT
KDevelop finishes parsing the file in a reasonably short time (less than a
minute perhaps).
BACKTRACE
#0 KDevHash::operator<< <unsigned int>() at
kdevelop/kdevplatform/language/util/kdevhash.h:48
#1 KDevelop::AbstractType::hash() at
kdevelop/kdevplatform/language/duchain/types/abstracttype.cpp:130
#2 KDevelop::IntegralType::hash() at
kdevelop/kdevplatform/language/duchain/types/integraltype.cpp:145
#3 KDevelop::AbstractTypeDataRequest::hash() at
kdevelop/kdevplatform/language/duchain/types/typerepository.cpp:36
#4 KDevelop::Bucket<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, 0u>::findIndex() at
kdevelop/kdevplatform/serialization/itemrepository.h:266
#5 KDevelop::ItemRepository<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, QRecursiveMutex, 0u,
1048576u>::index(KDevelop::AbstractTypeDataRequest const&)::{lambda(unsigned
short, KDevelop::Bucket<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, 0u> const*)#1}::operator()(unsigned
short, KDevelop::Bucket<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, 0u> const*) const() at
kdevelop/kdevplatform/serialization/itemrepository.h:1,153
#6 KDevelop::ItemRepository<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, QRecursiveMutex, 0u,
1048576u>::walkBucketChain<KDevelop::ItemRepository<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, QRecursiveMutex, 0u,
1048576u>::index(KDevelop::AbstractTypeDataRequest const&)::{lambda(unsigned
short, KDevelop::Bucket<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, 0u> const*)#1}>(unsigned int,
KDevelop::ItemRepository<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, QRecursiveMutex, 0u,
1048576u>::index(KDevelop::AbstractTypeDataRequest const&)::{lambda(unsigned
short, KDevelop::Bucket<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, 0u> const*)#1} const&) const() at
kdevelop/kdevplatform/serialization/itemrepository.h:1,957
#7 KDevelop::ItemRepository<KDevelop::AbstractTypeData,
KDevelop::AbstractTypeDataRequest, true, QRecursiveMutex, 0u,
1048576u>::index() at
kdevelop/kdevplatform/serialization/itemrepository.h:1,150
#8 operator()() at
kdevelop/kdevplatform/language/duchain/types/typerepository.cpp:120
#9 KDevelop::LockedItemRepository::write<KDevelop::AbstractType,
KDevelop::TypeRepository::indexForType(const
KDevelop::AbstractType::Ptr&)::<lambda(KDevelop::TypeItemRepository&)> >(struct
{...} &&)() at kdevelop/kdevplatform/serialization/itemrepository.h:2,312
#10 KDevelop::TypeRepository::indexForType() at
kdevelop/kdevplatform/language/duchain/types/typerepository.cpp:118
#11 KDevelop::IndexedType::IndexedType() at
kdevelop/kdevplatform/language/duchain/types/indexedtype.cpp:14
#12 KDevelop::AbstractType::indexed() at
kdevelop/kdevplatform/language/duchain/types/abstracttype.cpp:117
#13 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:770
#14 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#15 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#16 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#17 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#18 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#19 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#20 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#21 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#22 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#23 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#24 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#25 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#26 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#27 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#28 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#29 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#30 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#31 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#32 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#33 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#34 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#35 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#36 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#37 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#38 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#39 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#40 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#41 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#42 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#43 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#44 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#45 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#46 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#47 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#48 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#49 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#50 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#51 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#52 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#53 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#54 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#55 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#56 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#57 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#58 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#59 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#60 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#61 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#62 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#63 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#64 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#65 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#66 (anonymous namespace)::Visitor::createType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:619
#67 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)107>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#68 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,439
#69 (anonymous namespace)::Visitor::createClassTemplateSpecializationType() at
kdevelop/plugins/clang/duchain/builder.cpp:766
#70 (anonymous namespace)::Visitor::createType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:645
#71 (anonymous namespace)::Visitor::dispatchType<(CXTypeKind)1>() at
kdevelop/plugins/clang/duchain/builder.cpp:369
#72 (anonymous namespace)::Visitor::makeType() at
kdevelop/plugins/clang/duchain/builder.cpp:1,444
#73 (anonymous namespace)::Visitor::makeAbsType() at
kdevelop/plugins/clang/duchain/builder.cpp:337
#74 (anonymous namespace)::Visitor::createType<(CXCursorKind)36>() at
kdevelop/plugins/clang/duchain/builder.cpp:675
#75 (anonymous namespace)::Visitor::createDeclaration<(CXCursorKind)36,
KDevelop::Declaration>() at kdevelop/plugins/clang/duchain/builder.cpp:457
#76 (anonymous namespace)::Visitor::buildDeclaration<(CXCursorKind)36,
KDevelop::Declaration, false>() at
kdevelop/plugins/clang/duchain/builder.cpp:1,291
#77 (anonymous namespace)::Visitor::dispatchCursor<(CXCursorKind)36,
(Decision)1, (Decision)1>() at kdevelop/plugins/clang/duchain/builder.cpp:1,007
#78 (anonymous namespace)::Visitor::dispatchCursor<(CXCursorKind)36>() at
kdevelop/plugins/clang/duchain/builder.cpp:971
#79 (anonymous namespace)::visitCursor() at
kdevelop/plugins/clang/duchain/builder.cpp:1,677
#80 ??() at /usr/lib/libclang.so.13
#81 ??() at /usr/lib/libclang.so.13
#82 ??() at /usr/lib/libclang.so.13
#83 ??() at /usr/lib/libclang.so.13
#84 clang_visitChildren() at /usr/lib/libclang.so.13
#85 (anonymous namespace)::Visitor::Visitor() at
kdevelop/plugins/clang/duchain/builder.cpp:1,590
#86 Builder::visit() at kdevelop/plugins/clang/duchain/builder.cpp:1,737
#87 ClangHelpers::buildDUChain(void*, QMultiHash<void*, Import> const&,
ParseSession const&, QFlags<KDevelop::TopDUContext::Feature>, QHash<void*,
KDevelop::ReferencedTopDUContext>&, QHash<KDevelop::IndexedString,
KDevelop::ModificationRevision> const&, KDevelop::IndexedString const&,
ClangIndex*, std::function<bool ()> const&)() at
kdevelop/plugins/clang/duchain/clanghelpers.cpp:209
#88 ClangParseJob::run() at kdevelop/plugins/clang/clangparsejob.cpp:322
#89 ThreadWeaver::IdDecorator::run(QSharedPointer<ThreadWeaver::JobInterface>,
ThreadWeaver::Thread*)() at /usr/lib/libKF5ThreadWeaver.so.5
#90 ThreadWeaver::Executor::run(QSharedPointer<ThreadWeaver::JobInterface>
const&, ThreadWeaver::Thread*)() at /usr/lib/libKF5ThreadWeaver.so.5
#91 ThreadWeaver::Job::execute(QSharedPointer<ThreadWeaver::JobInterface>
const&, ThreadWeaver::Thread*)() at /usr/lib/libKF5ThreadWeaver.so.5
#92 ThreadWeaver::Thread::run()() at /usr/lib/libKF5ThreadWeaver.so.5
#93 ??() at /usr/lib/libQt5Core.so.5
#94 ??() at /usr/lib/libc.so.6
#95 ??() at /usr/lib/libc.so.6
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