Unverified Commit 609fe2cb authored by Daniel Bertalan's avatar Daniel Bertalan Committed by GitHub
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[ObjC] Fix offsets following `[[no_unique_address]]` for `@encode()` (#71321) 

Commit 46ca880f made `@encode` skip fields that are made zero-sized by
`[[no_unique_address]]`. When iterating the fields, the index which is
passed to `getFieldOffset` failed to be incremented for those due to the
use of an early `continue`, so subsequent fields reported an incorrect
offset. This caused an assertion to be triggered in
`getObjCEncodingForStructureImpl`.

Fixes #71250
parent 1ad920f0

clang/lib/AST/ASTContext.cpp

+1 −3
Original line number Diff line number Diff line
@@ -8541,14 +8541,12 @@ void ASTContext::getObjCEncodingForStructureImpl(RecordDecl *RDecl, 
    }

  }



  unsigned i = 0;

  for (FieldDecl *Field : RDecl->fields()) {

    if (!Field->isZeroLengthBitField(*this) && Field->isZeroSize(*this))

      continue;

    uint64_t offs = layout.getFieldOffset(i);

    uint64_t offs = layout.getFieldOffset(Field->getFieldIndex());

    FieldOrBaseOffsets.insert(FieldOrBaseOffsets.upper_bound(offs),

                              std::make_pair(offs, Field));

    ++i;

  }



  if (CXXRec && includeVBases) {

clang/test/CodeGenObjCXX/encode.mm

+14 −0
Original line number Diff line number Diff line
@@ -339,3 +339,17 @@ const char *a0 = @encode(Array0); 
const char *inner0 = @encode(Outer0<int>::Inner0 *);

const char *inner1 = @encode(Outer0<int>::Inner1<float> *);

}



#if __cplusplus >= 202002L

namespace GH71250 {

  struct Empty {};

  struct S {

    [[no_unique_address]] Empty a;

    long b;

    long c;

  };



  // CHECKCXX20: @_ZN7GH712501sE =  constant [7 x i8] c"{S=qq}\00", align 1

  extern const char s[] = @encode(S);

}

#endif