[PATCH] D59103: [clang-tidy] New checker bugprone-incomplete-comparison-operator

[Kalle Huttunen via Phabricator via cfe-commits]

kallehuttunen added a comment.

The checker gives quite many warnings on LLVM code base. For example, running it for lib/Transforms/Scalar:

  /home/kalle/llvm/lib/Transforms/Scalar/GVN.cpp:119:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator==(const Expression &other) const {
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/GVN.cpp:119:3: note: commutative not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVN.cpp:119:3: note: other.commutative not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:151:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator==(const CHIArg &A) { return VN == A.VN; }
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:151:3: note: Dest not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:151:3: note: I not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:151:3: note: A.Dest not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:151:3: note: A.I not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:152:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator!=(const CHIArg &A) { return !(*this == A); }
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:152:3: note: Dest not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:152:3: note: I not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:152:3: note: A.Dest not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNHoist.cpp:152:3: note: A.I not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator>(const SinkingInstructionCandidate &Other) const {
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: NumBlocks not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: NumInstructions not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: NumPHIs not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: NumMemoryInsts not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: Blocks not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: Other.NumBlocks not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: Other.NumInstructions not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: Other.NumPHIs not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: Other.NumMemoryInsts not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/GVNSink.cpp:211:3: note: Other.Blocks not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/MergeICmps.cpp:90:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator<(const BCEAtom &O) const {
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/MergeICmps.cpp:90:3: note: GEP not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/MergeICmps.cpp:90:3: note: LoadI not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/MergeICmps.cpp:90:3: note: O.GEP not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/MergeICmps.cpp:90:3: note: O.LoadI not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/NewGVN.cpp:436:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator==(const Expression &Other) const {
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/NewGVN.cpp:436:3: note: Other.Opcode not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/NewGVN.cpp:436:3: note: Other.HashVal not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:206:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    friend LLVM_ATTRIBUTE_UNUSED bool operator<(const Slice &LHS,
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:206:3: note: LHS.EndOffset not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:206:3: note: LHS.UseAndIsSplittable not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:210:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    friend LLVM_ATTRIBUTE_UNUSED bool operator<(uint64_t LHSOffset,
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:210:3: note: RHS.EndOffset not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:210:3: note: RHS.UseAndIsSplittable not accessed
  
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:582:3: warning: incomplete comparison operator [bugprone-incomplete-comparison-operator]
    bool operator==(const partition_iterator &RHS) const {
    ^
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:582:3: note: MaxSplitSliceEndOffset not accessed
  /home/kalle/llvm/lib/Transforms/Scalar/SROA.cpp:582:3: note: RHS.MaxSplitSliceEndOffset not accessed

Running the checker on 100k SLOC proprietary code base I'm working with resulted in finding 5 bugs and 1 false positive (the code had a comment that one member was not accessed on purpose).

I'm anticipating that the checker can produce lots of false positives in some code bases because of `operator<`. That's why I'm making the checked operators configurable from the start.


Repository:
  rCTE Clang Tools Extra

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  https://reviews.llvm.org/D59103/new/

https://reviews.llvm.org/D59103