dcoughlin added inline comments.
================
Comment at: lib/StaticAnalyzer/Core/ExprEngineC.cpp:462
+ case CK_ReinterpretMemberPointer: {
+ const Expr *UOExpr = CastE->getSubExpr()->IgnoreParenCasts();
+ assert(isa<UnaryOperator>(UOExpr) &&
----------------
dcoughlin wrote:
> dcoughlin wrote:
> > I don't think pattern matching on the sub expression to find the
> > referred-to declaration is the right thing to do here. It isn't always the
> > case that the casted expression will be a unary pointer to member
> > operation. For example, this is perfectly fine and triggers an assertion
> > failure on your patch:
> >
> > ```
> > struct B {
> > int f;
> > };
> >
> > struct D : public B {
> > int g;
> > };
> >
> > void foo() {
> > D d;
> > d.f = 7;
> >
> > int B::* pfb = &B::f;
> > int D::* pfd = pfb;
> > int v = d.*pfd;
> > }
> > ```
> > Note that you can't just propagate the value already computed for the
> > subexpression. Here is a particularly annoying example from the C++ spec:
> >
> > ```
> > struct B {
> > int f;
> > };
> > struct L : public B { };
> > struct R : public B { };
> > struct D : public L, R { };
> >
> > void foo() {
> > D d;
> >
> > int B::* pb = &B::f;
> > int L::* pl = pb;
> > int R::* pr = pb;
> >
> > int D::* pdl = pl;
> > int D::* pdr = pr;
> >
> > clang_analyzer_eval(pdl == pdr); // FALSE
> > clang_analyzer_eval(pb == pl); // TRUE
> > }
> > ```
> > My guess is this will require accumulating CXXBasePath s or something
> > similar for each cast. I don't know how to do this efficiently.
> > I don't know how to do this efficiently.
>
> Jordan suggested storing this in a bump-pointer allocated object with a
> lifetime of the AnalysisDeclContext. The common case is no multiple
> inheritance, so that should be the fast case.
>
> Maybe the Data could be a pointer union between a DeclaratorDecl and an
> immutable linked list (with sharing) of CXXBaseSpecifiers from the CastExprs
> in the AST. The storage for this could be managed with a new manager in
> SValBuilder.
(The bump pointer-allocated thing would have to have the Decl as well.)
This could also probably live in BasicValueFactory. The extra data would be
similar to LazyCompoundValData.
https://reviews.llvm.org/D25475
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
