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:
> 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.
https://reviews.llvm.org/D25475
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