Author: majnemer Date: Thu Feb 25 22:23:19 2016 New Revision: 261975 URL: http://llvm.org/viewvc/llvm-project?rev=261975&view=rev Log: [MSVC Compat] Don't evaluate member base expressions w/o side effects
A member expression's base doesn't always have an impact on what the member decl would evaluate to. In such a case, the base is used as a poor man's scope qualifier. This fixes PR26738. Differential Revision: http://reviews.llvm.org/D17619 Added: cfe/trunk/test/SemaCXX/ms-const-member-expr.cpp Modified: cfe/trunk/lib/AST/ExprConstant.cpp Modified: cfe/trunk/lib/AST/ExprConstant.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=261975&r1=261974&r2=261975&view=diff ============================================================================== --- cfe/trunk/lib/AST/ExprConstant.cpp (original) +++ cfe/trunk/lib/AST/ExprConstant.cpp Thu Feb 25 22:23:19 2016 @@ -4427,6 +4427,15 @@ public: void VisitIgnoredValue(const Expr *E) { EvaluateIgnoredValue(Info, E); } + + /// Potentially visit a MemberExpr's base expression. + void VisitIgnoredBaseExpression(const Expr *E) { + // While MSVC doesn't evaluate the base expression, it does diagnose the + // presence of side-effecting behavior. + if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx)) + return; + VisitIgnoredValue(E); + } }; } @@ -4750,14 +4759,14 @@ bool LValueExprEvaluator::VisitCXXUuidof bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) { // Handle static data members. if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) { - VisitIgnoredValue(E->getBase()); + VisitIgnoredBaseExpression(E->getBase()); return VisitVarDecl(E, VD); } // Handle static member functions. if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) { if (MD->isStatic()) { - VisitIgnoredValue(E->getBase()); + VisitIgnoredBaseExpression(E->getBase()); return Success(MD); } } @@ -6078,7 +6087,7 @@ public: } bool VisitMemberExpr(const MemberExpr *E) { if (CheckReferencedDecl(E, E->getMemberDecl())) { - VisitIgnoredValue(E->getBase()); + VisitIgnoredBaseExpression(E->getBase()); return true; } Added: cfe/trunk/test/SemaCXX/ms-const-member-expr.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/ms-const-member-expr.cpp?rev=261975&view=auto ============================================================================== --- cfe/trunk/test/SemaCXX/ms-const-member-expr.cpp (added) +++ cfe/trunk/test/SemaCXX/ms-const-member-expr.cpp Thu Feb 25 22:23:19 2016 @@ -0,0 +1,19 @@ +// RUN: %clang_cc1 %s -std=c++11 -fms-compatibility -fsyntax-only -verify + +struct S { + enum { E = 1 }; + static const int sdm = 1; +}; + +void f(S *s) { + char array[s->E] = { 0 }; +} + +extern S *s; +constexpr int e1 = s->E; + +S *side_effect(); // expected-note{{declared here}} +constexpr int e2 = // expected-error{{must be initialized by a constant expression}} + side_effect()->E; // expected-note{{cannot be used in a constant expression}} + +constexpr int e4 = s->sdm; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
