[clang++] Assertion `(data().DefaultedCopyConstructorIsDeleted || needsOverloadResolutionForCopyConstructor()) && "Copy constructor should not be deleted"' failed.

[yijan4845]

This testcase is generated by a fuzzer.

Compiler Explorer: https://godbolt.org/z/j7TdET3Y6

This invalid code will crash on Clang Assertion Trunk, it seems that this goes back to clang-11:

struct A {
  virtual A(const A&);
};

struct B {
  B();
  A a;
} b;

This is possibly related to 74581 and 42545.

Stack dump:

clang++: /root/llvm-project/clang/include/clang/AST/DeclCXX.h:871: void clang::CXXRecordDecl::setImplicitCopyConstructorIsDeleted(): Assertion `(data().DefaultedCopyConstructorIsDeleted || needsOverloadResolutionForCopyConstructor()) && "Copy constructor should not be deleted"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics <source>
1.	<source>:8:4: current parser token ';'
 #0 0x0000000003bae128 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bae128)
 #1 0x0000000003babdec llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3babdec)
 #2 0x0000000003af9048 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007db1dac42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007db1dac969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007db1dac42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007db1dac287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007db1dac2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x00007db1dac39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000006b2a1ad clang::Sema::DeclareImplicitCopyConstructor(clang::CXXRecordDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b2a1ad)
#10 0x0000000006ebdcaf void llvm::function_ref<void ()>::callback_fn<clang::Sema::LookupConstructors(clang::CXXRecordDecl*)::'lambda'()>(long) SemaLookup.cpp:0:0
#11 0x00000000067bc9f1 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67bc9f1)
#12 0x0000000006ebdfc3 clang::Sema::LookupConstructors(clang::CXXRecordDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6ebdfc3)
#13 0x0000000006e8e6ea TryConstructorInitialization(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::QualType, clang::QualType, clang::InitializationSequence&, bool, bool) SemaInit.cpp:0:0
#14 0x0000000006e970bb clang::InitializationSequence::InitializeFrom(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6e970bb)
#15 0x00000000069f427c clang::Sema::ActOnUninitializedDecl(clang::Decl*) (.part.0) SemaDecl.cpp:0:0
#16 0x000000000667ba88 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x667ba88)
#17 0x000000000668b4a9 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x668b4a9)
#18 0x000000000664b51e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x664b51e)
#19 0x000000000664bcde clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x664bcde)
#20 0x0000000006653473 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6653473)
#21 0x000000000665435d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x665435d)
#22 0x000000000664687a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x664687a)
#23 0x0000000004507088 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4507088)
#24 0x00000000047c1509 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47c1509)
#25 0x000000000474008e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x474008e)
#26 0x00000000048a70de clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48a70de)
#27 0x0000000000cdc07f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcdc07f)
#28 0x0000000000cd3d8a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#29 0x000000000454ad99 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#30 0x0000000003af94f4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3af94f4)
#31 0x000000000454b38f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#32 0x0000000004510c8d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4510c8d)
#33 0x0000000004511d7d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4511d7d)
#34 0x00000000045196a5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x45196a5)
#35 0x0000000000cd8f4f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd8f4f)
#36 0x0000000000ba8474 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xba8474)
#37 0x00007db1dac29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#38 0x00007db1dac29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#39 0x0000000000cd383e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd383e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Yihan Yang (yijan4845)

**This testcase is generated by a fuzzer.**

Compiler Explorer: https://godbolt.org/z/j7TdET3Y6

This invalid code will crash on Clang Assertion Trunk, it seems that this goes back to clang-11:

struct A {
  virtual A(const A&);
};

struct B {
  B();
  A a;
} b;

This is possibly related to 74581 and 42545.

Stack dump:

clang++: /root/llvm-project/clang/include/clang/AST/DeclCXX.h:871: void clang::CXXRecordDecl::setImplicitCopyConstructorIsDeleted(): Assertion `(data().DefaultedCopyConstructorIsDeleted || needsOverloadResolutionForCopyConstructor()) && "Copy constructor should not be deleted"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics <source>
1.	<source>:8:4: current parser token ';'
 #<!-- -->0 0x0000000003bae128 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3bae128)
 #<!-- -->1 0x0000000003babdec llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3babdec)
 #<!-- -->2 0x0000000003af9048 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #<!-- -->3 0x00007db1dac42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #<!-- -->4 0x00007db1dac969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #<!-- -->5 0x00007db1dac42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #<!-- -->6 0x00007db1dac287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #<!-- -->7 0x00007db1dac2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #<!-- -->8 0x00007db1dac39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #<!-- -->9 0x0000000006b2a1ad clang::Sema::DeclareImplicitCopyConstructor(clang::CXXRecordDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6b2a1ad)
#<!-- -->10 0x0000000006ebdcaf void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::Sema::LookupConstructors(clang::CXXRecordDecl*)::'lambda'()&gt;(long) SemaLookup.cpp:0:0
#<!-- -->11 0x00000000067bc9f1 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x67bc9f1)
#<!-- -->12 0x0000000006ebdfc3 clang::Sema::LookupConstructors(clang::CXXRecordDecl*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6ebdfc3)
#<!-- -->13 0x0000000006e8e6ea TryConstructorInitialization(clang::Sema&amp;, clang::InitializedEntity const&amp;, clang::InitializationKind const&amp;, llvm::MutableArrayRef&lt;clang::Expr*&gt;, clang::QualType, clang::QualType, clang::InitializationSequence&amp;, bool, bool) SemaInit.cpp:0:0
#<!-- -->14 0x0000000006e970bb clang::InitializationSequence::InitializeFrom(clang::Sema&amp;, clang::InitializedEntity const&amp;, clang::InitializationKind const&amp;, llvm::MutableArrayRef&lt;clang::Expr*&gt;, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6e970bb)
#<!-- -->15 0x00000000069f427c clang::Sema::ActOnUninitializedDecl(clang::Decl*) (.part.0) SemaDecl.cpp:0:0
#<!-- -->16 0x000000000667ba88 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&amp;, clang::Parser::ParsedTemplateInfo const&amp;, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x667ba88)
#<!-- -->17 0x000000000668b4a9 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&amp;, clang::DeclaratorContext, clang::ParsedAttributes&amp;, clang::Parser::ParsedTemplateInfo&amp;, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x668b4a9)
#<!-- -->18 0x000000000664b51e clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec&amp;, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x664b51e)
#<!-- -->19 0x000000000664bcde clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x664bcde)
#<!-- -->20 0x0000000006653473 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&amp;, clang::ParsedAttributes&amp;, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6653473)
#<!-- -->21 0x000000000665435d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr&lt;clang::DeclGroupRef&gt;&amp;, clang::Sema::ModuleImportState&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x665435d)
#<!-- -->22 0x000000000664687a clang::ParseAST(clang::Sema&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x664687a)
#<!-- -->23 0x0000000004507088 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4507088)
#<!-- -->24 0x00000000047c1509 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47c1509)
#<!-- -->25 0x000000000474008e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x474008e)
#<!-- -->26 0x00000000048a70de clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x48a70de)
#<!-- -->27 0x0000000000cdc07f cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcdc07f)
#<!-- -->28 0x0000000000cd3d8a ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->29 0x000000000454ad99 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const::'lambda'()&gt;(long) Job.cpp:0:0
#<!-- -->30 0x0000000003af94f4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3af94f4)
#<!-- -->31 0x000000000454b38f clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const (.part.0) Job.cpp:0:0
#<!-- -->32 0x0000000004510c8d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4510c8d)
#<!-- -->33 0x0000000004511d7d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4511d7d)
#<!-- -->34 0x00000000045196a5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x45196a5)
#<!-- -->35 0x0000000000cd8f4f clang_main(int, char**, llvm::ToolContext const&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd8f4f)
#<!-- -->36 0x0000000000ba8474 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xba8474)
#<!-- -->37 0x00007db1dac29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->38 0x00007db1dac29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->39 0x0000000000cd383e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xcd383e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

[sookach]

Hey @shafik, I can take a look at this issue.

[shafik]

Hey @shafik, I can take a look at this issue.

I looked at it briefly.

I tried handling it here:

llvm-project/clang/lib/Sema/SemaDecl.cpp

Lines 9250 to 9255 in 685bec7

	R = SemaRef.CheckConstructorDeclarator(D, R, SC);
	return CXXConstructorDecl::Create(
	SemaRef.Context, cast<CXXRecordDecl>(DC), D.getBeginLoc(), NameInfo, R,
	TInfo, ExplicitSpecifier, SemaRef.getCurFPFeatures().isFPConstrained(),
	isInline, /*isImplicitlyDeclared=*/false, ConstexprKind,
	InheritedConstructor(), TrailingRequiresClause);

because D.isInvalidType() is true but that mess up error recovery and clang/test/SemaCXX/constructor-recovery.cpp fails.

I did not spend enough time to find a better location for handling this.

CC @hokein may have a better idea.

[hokein]

because D.isInvalidType() is true but that messes up error recovery, causing clang/test/SemaCXX/constructor-recovery.cpp to fail.

Are you proposing a bailout when D.isInvalidType() == true? This will drop the entire constructor decl.

It seems like there is conflicting information in the AST for class A:

-CXXRecordDecl 0x560681e25178 </t/t3.cpp:26:1, line:28:1> line:26:8 struct A definition
  |-DefinitionData empty aggregate standard_layout trivially_copyable pod trivial literal has_constexpr_non_copy_move_ctor can_const_default_init
  | |-DefaultConstructor exists trivial constexpr needs_implicit defaulted_is_constexpr
  | |-CopyConstructor simple trivial has_const_param needs_implicit implicit_has_const_param
  | |-MoveConstructor exists simple trivial needs_implicit
  | |-CopyAssignment simple trivial has_const_param needs_implicit implicit_has_const_param
  | |-MoveAssignment exists simple trivial needs_implicit
  | `-Destructor simple irrelevant trivial needs_implicit
  |-CXXRecordDecl 0x560681e25298 <col:1, col:8> col:8 implicit referenced struct A
  `-CXXConstructorDecl 0x560681e25530 <line:27:4, col:22> col:12 invalid A 'void (const A &)'
    `-ParmVarDecl 0x560681e253d8 <col:14, col:21> col:22 'const A &'

Here, the CXXRecordDecl for A shows that the class has a user-provided copy constructor, but it is marked as invalid due to an incorrect virtual keyword. However, the DefinitionData still considers the copy constructor to be trivial, indicating no user-provided constructor. This inconsistency seems to be the root of the issue.

I think we need to take a look how the invalid copy constructor is being handled, particularly how the DefinitionData is populated. We need to avoid situations where invalid constructors cause inconsistencies in the AST.