[PATCH] D65445: [CrossTU] Handle case when no USR could be generated during Decl search.

[Gabor Marton via Phabricator via cfe-commits]

martong added a comment.

In D65445#1608277 <https://reviews.llvm.org/D65445#1608277>, @balazske wrote:

> Probably this is a problem case too but only if the `f` or `i` has an initializer expression and really no USR is generated for `f` or `i`. But what I have found is that there is a `VarDecl` for a "invisible" variable whose type is the anonymous union and it has a (default) initializer too. If the search reaches DC of the `f` it will try to get the USR for this variable.


OK. Just for the record and for later reference, I copy the test code and the AST here.

  class TestAnonUnionUSR {
  public:
    inline float f(int value) {
      union {
        float f;
        int i;
      };
      i = value;
      return f;
    }
    static const int Test;
  };



  `-CXXRecordDecl 0xdb9fe0 </tmp/usr.cpp:1:1, line:12:1> line:1:7 class TestAnonUnionUSR definition
    |-DefinitionData pass_in_registers 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 trivial has_const_param needs_implicit implicit_has_const_param
    | |-MoveAssignment exists simple trivial needs_implicit
    | `-Destructor simple irrelevant trivial needs_implicit
    |-CXXRecordDecl 0xdba0f8 <col:1, col:7> col:7 implicit class TestAnonUnionUSR
    |-AccessSpecDecl 0xdba188 <line:2:1, col:7> col:1 public
    |-CXXMethodDecl 0xdba2c0 <line:3:3, line:10:3> line:3:16 f 'float (int)' inline
    | |-ParmVarDecl 0xdba1c8 <col:18, col:22> col:22 used value 'int'
    | `-CompoundStmt 0xdbae70 <col:29, line:10:3>
    |   |-DeclStmt 0xdbac68 <line:4:5, line:7:6>
    |   | |-CXXRecordDecl 0xdba400 <line:4:5, line:7:5> line:4:5 union definition
    |   | | |-DefinitionData pass_in_registers aggregate standard_layout trivially_copyable pod trivial literal has_variant_members
    |   | | | |-DefaultConstructor exists trivial
    |   | | | |-CopyConstructor simple trivial has_const_param implicit_has_const_param
    |   | | | |-MoveConstructor exists simple trivial
    |   | | | |-CopyAssignment trivial has_const_param needs_implicit implicit_has_const_param
    |   | | | |-MoveAssignment exists simple trivial needs_implicit
    |   | | | `-Destructor simple irrelevant trivial needs_implicit
    |   | | |-FieldDecl 0xdba530 <line:5:7, col:13> col:13 referenced f 'float'
    |   | | |-FieldDecl 0xdba598 <line:6:7, col:11> col:11 referenced i 'int'
    |   | | |-CXXConstructorDecl 0xdba6d8 <line:4:5> col:5 implicit used  'void () noexcept' inline default trivial
    |   | | | `-CompoundStmt 0xdbab68 <col:5>
    |   | | |-CXXConstructorDecl 0xdba808 <col:5> col:5 implicit constexpr  'void (const (anonymous union at /tmp/usr.cpp:4:5) &)' inline default trivial noexcept-unevaluated 0xdba808
    |   | | | `-ParmVarDecl 0xdba918 <col:5> col:5 'const (anonymous union at /tmp/usr.cpp:4:5) &'
    |   | | `-CXXConstructorDecl 0xdba9b8 <col:5> col:5 implicit constexpr  'void ((anonymous union at /tmp/usr.cpp:4:5) &&)' inline default trivial noexcept-unevaluated 0xdba9b8
    |   | |   `-ParmVarDecl 0xdbaac8 <col:5> col:5 '(anonymous union at /tmp/usr.cpp:4:5) &&'
    |   | `-VarDecl 0xdba658 <col:5> col:5 implicit used '(anonymous union at /tmp/usr.cpp:4:5)' callinit
    |   |   `-CXXConstructExpr 0xdbab78 <col:5> '(anonymous union at /tmp/usr.cpp:4:5)' 'void () noexcept'
    |   |-BinaryOperator 0xdbad08 <line:8:5, col:9> 'int' lvalue '='
    |   | |-MemberExpr 0xdbaca0 <col:5> 'int' lvalue .i 0xdba598
    |   | | `-DeclRefExpr 0xdbac80 <col:5> '(anonymous union at /tmp/usr.cpp:4:5)' lvalue Var 0xdba658 '' '(anonymous union at /tmp/usr.cpp:4:5)'
    |   | `-ImplicitCastExpr 0xdbacf0 <col:9> 'int' <LValueToRValue>
    |   |   `-DeclRefExpr 0xdbacd0 <col:9> 'int' lvalue ParmVar 0xdba1c8 'value' 'int'
    |   `-ReturnStmt 0xdbae60 <line:9:5, col:12>
    |     `-ImplicitCastExpr 0xdbae48 <col:12> 'float' <LValueToRValue>
    |       `-MemberExpr 0xdbae18 <col:12> 'float' lvalue .f 0xdba530
    |         `-DeclRefExpr 0xdbadf8 <col:12> '(anonymous union at /tmp/usr.cpp:4:5)' lvalue Var 0xdba658 '' '(anonymous union at /tmp/usr.cpp:4:5)'
    `-VarDecl 0xdba380 <line:11:3, col:20> col:20 Test 'const int' static


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