[cfe-dev] RecursiveASTVisitor::TraverseStmt for UnaryOperator's

[Hugues de Lassus]

Hi everyone,

I have a RecursiveASTVisitor that overrides the TraverseStmt method and 
store every node in a stack, to be able to know what the last traversed 
Stmt was when visiting a node, like this :

bool MyVisitor::TraverseStmt(Stmt* S) {
     DEBUG(llvm::errs() << S << "\n";
                 S->dumpColor());

     NodeStack.push_back(DynTypedNode::create<Stmt>(*S));
     RecursiveASTVisitor::TraverseStmt(S);
     NodeStack.pop_back();
     return true;
}

I did not find if there was already a way to do that in Clang, but 
still, it works well for almost every node.
But *almost* means that it does not traverse at least *some* 
UnaryOperator's nodes. It does traverse UO_(Post|Pre)(Inc|Dec) nodes but 
never does it traverse UO_AddrOf nor UO_Deref nodes.

This is the output snippet I get for *array = 3 :
0x2a0e7b8
BinaryOperator 0x2a0e7b8 'int' '='
|-UnaryOperator 0x2a0e778 'int' lvalue prefix '*'
| `-ImplicitCastExpr 0x2a0e760 'int *' <ArrayToPointerDecay>
|   `-DeclRefExpr 0x2a0e738 'int [2]' lvalue Var 0x29e0450 'array' 'int [2]'
`-IntegerLiteral 0x2a0e798 'int' 3
0x2a0e760
ImplicitCastExpr 0x2a0e760 'int *' <ArrayToPointerDecay>
`-DeclRefExpr 0x2a0e738 'int [2]' lvalue Var 0x29e0450 'array' 'int [2]'
0x2a0e738
DeclRefExpr 0x2a0e738 'int [2]' lvalue Var 0x29e0450 'array' 'int [2]'
no uoparent was found for array
0x2a0e798
IntegerLiteral 0x2a0e798 'int' 3

It does show that we "skip" the UO traversal. But for ++x; it does dump 
the UOperator node. Would this be a bug?

I also tried to override TraverseUnaryOperator but my program never went 
through this method, even though I when I commented out TraverseStmt.

Does anyone have an idea why UO_AddrOf and UO_Deref are never traversed ?

-- 

Hugues de Lassus Saint-Geniès