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clangabstract-syntax-treelibtooling

Usage of ParentMap in Clang

There seems to be no examples online, according to the documentation Path, ParentMap's constructor accepts "Stmt *ASTRoot", which may means that later the ParentMap instance will find parents under the AST subtree under "ASTRoot". But how to get the root node of a translation unit? I tried 

virtual bool VisitTranslationUnitDecl(TranslationUnitDecl *decl) {
    //decl->dump();
    Stmt *stmt = decl->getBody();
    mParentMap = new ParentMap(stmt);
    return true;
}

The goal is to create a ParentMap around the root nood then use it in other Visit*** callbacks during the scan process. But decl->getBody() is null. decl->dump() will print everything, and even scan the AST for the second time decl->getBody() is still null.

How to get the root Stmt of an AST? What is the right/better way to use ParentMap?

Solution

  • ParentMap is not really intended to be used on its own. You can use ASTContext::getParents, which constructs and maintains ParentMap.