[LLVMbugs] [Bug 3330] New: ImplicitCastExpr with NULL pointer to subexpression.

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=3330

           Summary: ImplicitCastExpr with NULL pointer to subexpression.
           Product: clang
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: AST
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: bolzoni at cs.unipr.it
                CC: llvmbugs at cs.uiuc.edu, bagnara at cs.unipr.it


Test case:
--->
enum E {
 A,
 B = A + (((-2UL << 20) - (-10UL << 20)) >> 12) - 1,
 C
};
---<

to see the bug you need to modify the function
void DeclContextPrinter::PrintDeclContext(const DeclContext*, unsigned)
in the file Driver/ASTConsumer.cpp.

seek for `case Decl::EnumConstant:', add
--->
const Expr* e = ECD-> getInitExpr();
if (e) {
  e-> dumpAll();
}
---<
just before the break statement.
Recompile.

The output of clang -print-decl-contexts will be:
--->
(ImplicitCastExpr 0x1e84af0 'int'
  (BinaryOperator 0x1e849f0 'unsigned long' '-'
    (BinaryOperator 0x1e84930 'unsigned long' '+'
      (ImplicitCastExpr 0x1e848f0 'unsigned long'
        (DeclRefExpr 0x1e844f0 'int' EnumConstant='A' 0x1e84490))
      (ParenExpr 0x1e848b0 'unsigned long'
        (BinaryOperator 0x1e84870 'unsigned long' '>>'
          (ParenExpr 0x1e847f0 'unsigned long'
            (BinaryOperator 0x1e847b0 'unsigned long' '-'
              (ParenExpr 0x1e84630 'unsigned long'
                (BinaryOperator 0x1e845f0 'unsigned long' '<<'
                  (UnaryOperator 0x1e84570 'unsigned long' prefix '-'
                    (IntegerLiteral 0x1e84530 'unsigned long' 2))
                  (IntegerLiteral 0x1e845b0 'int' 20)))
              (ParenExpr 0x1e84770 'unsigned long'
                (BinaryOperator 0x1e84730 'unsigned long' '<<'
                  (UnaryOperator 0x1e846b0 'unsigned long' prefix '-'
                    (IntegerLiteral 0x1e84670 'unsigned long' 10))
                  (IntegerLiteral 0x1e846f0 'int' 20)))))
          (IntegerLiteral 0x1e84830 'int' 12))))
    (ImplicitCastExpr 0x1e849b0 'unsigned long'
      (IntegerLiteral 0x1e84970 'int' 1))))
(ImplicitCastExpr 0x1e84b30 'int'
  <<<NULL>>>)
[translation unit] 0x1e6dfa0
    [struct] __va_list_tag
        <field> [omitted]
    <typedef> __builtin_va_list
    [enum] E
        <enum constant> A
        <enum constant> B
        <enum constant> C
---<

The last ImplicitCastExpr has NULL as sub-expression.


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