valgrind error in function NoteFunctionCandidate, file SemaOverload.cpp line 11961

[dcb314]

cvise $ /home/dcb40b/valgrind/results/bin/valgrind -q --trace-children=yes /home/dcb40b/llvm/results/bin/clang++ -c bug157.cc
==1668426== Conditional jump or move depends on uninitialised value(s)
==1668426== at 0x47E3526: NoteFunctionCandidate (SemaOverload.cpp:11961)
==1668426== by 0x47E3526: clang::OverloadCandidateSet::NoteCandidates(clang::Sema&, llvm::ArrayRefclang::Expr*, llvm::ArrayRefclang::OverloadCandidate*, llvm::StringRef, clang::SourceLocation) (SemaOverload.cpp:12591)

bug157.cc.gz

File SemaOverload.cpp, line 11961 is

  !Cand->Function->hasCXXExplicitFunctionObjectParameter() &&

This bug has existed since sometime before git hash 005758e,
dated 20240614.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (dcb314)

cvise $ /home/dcb40b/valgrind/results/bin/valgrind -q --trace-children=yes /home/dcb40b/llvm/results/bin/clang++ -c bug157.cc
==1668426== Conditional jump or move depends on uninitialised value(s)
==1668426== at 0x47E3526: NoteFunctionCandidate (SemaOverload.cpp:11961)
==1668426== by 0x47E3526: clang::OverloadCandidateSet::NoteCandidates(clang::Sema&, llvm::ArrayRef<clang::Expr*>, llvm::ArrayRef<clang::OverloadCandidate*>, llvm::StringRef, clang::SourceLocation) (SemaOverload.cpp:12591)

bug157.cc.gz

File SemaOverload.cpp, line 11961 is

  !Cand->Function->hasCXXExplicitFunctionObjectParameter() &&

This bug has existed since sometime before git hash 005758e,
dated 20240614.

[shafik]

This indeed looks like a bug, everywhere else Cand->Function is checked before using it.

This came in w/ d0223b9

CC @cor3ntin

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

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3. Fix the issue locally.
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If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: None (dcb314)

cvise $ /home/dcb40b/valgrind/results/bin/valgrind -q --trace-children=yes /home/dcb40b/llvm/results/bin/clang++ -c bug157.cc
==1668426== Conditional jump or move depends on uninitialised value(s)
==1668426== at 0x47E3526: NoteFunctionCandidate (SemaOverload.cpp:11961)
==1668426== by 0x47E3526: clang::OverloadCandidateSet::NoteCandidates(clang::Sema&, llvm::ArrayRef<clang::Expr*>, llvm::ArrayRef<clang::OverloadCandidate*>, llvm::StringRef, clang::SourceLocation) (SemaOverload.cpp:12591)

bug157.cc.gz

File SemaOverload.cpp, line 11961 is

  !Cand->Function->hasCXXExplicitFunctionObjectParameter() &&

This bug has existed since sometime before git hash 005758e,
dated 20240614.

[vortex73]

I'm looking into this issue. The issue is Cand->Function nott being checking in this case am I right?

[shafik]

I'm looking into this issue. The issue is Cand->Function nott being checking in this case am I right?

Yes, something like this:

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

Lines 9996 to 10000 in a78b19d

	if (Cand->Function) {
	Fns.erase(Cand->Function);
	if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate())
	Fns.erase(FunTmpl);
	}