With the patch :) On 07/29/2013 06:47 PM, Arnaud A. de Grandmaison wrote: > On 07/29/2013 06:17 PM, Jean-Daniel Dupas wrote: >> Le 29 juil. 2013 à 17:52, Arnaud A. de Grandmaison <[email protected]> >> a écrit : >> >>> Clang emits an error when typeid is used with -fno-rtti, but does not >>> perform a similar check for dynamic_cast. >>> >>> The attached patch implements the check. >>> >>> I have done it late in 'CastOperation::CheckDynamicCast' , as some >>> dynamic_cast can be resolved statically, and will thus require no >>> support from the runtime, but we may also want to be more paranoïd. >>> >>> Any thoughts ? >> If we want to support dynamic_cast without rtti when possible (as you do in >> your patch), you may add such case in the test to make sure clang accepts it. > Good point. I added a test for the 2 cases we accept (upcast, and cast > to same type). > >> -- Jean-Daniel >> >> >> >> >
-- Arnaud A. de Grandmaison
>From 64f1420f41a9b8d43eb6b5ae5f78696e7d2846bc Mon Sep 17 00:00:00 2001 From: "Arnaud A. de Grandmaison" <[email protected]> Date: Mon, 29 Jul 2013 18:43:27 +0200 Subject: [PATCH] Check dynamic_cast is not used with -fno-rtti, unless it is a noop or can be resolved statically. --- include/clang/Basic/DiagnosticSemaKinds.td | 2 ++ lib/Sema/SemaCast.cpp | 7 +++++++ test/SemaCXX/dynamic_cast-no-rtti.cpp | 22 ++++++++++++++++++++++ test/SemaCXX/no-rtti.cpp | 14 ++++++++++++++ 4 files changed, 45 insertions(+) create mode 100644 test/SemaCXX/dynamic_cast-no-rtti.cpp diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index 16619d9..b84f9bb 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/include/clang/Basic/DiagnosticSemaKinds.td @@ -5037,6 +5037,8 @@ def err_not_tag_in_scope : Error< def err_no_typeid_with_fno_rtti : Error< "cannot use typeid with -fno-rtti">; +def err_no_dynamic_cast_with_fno_rtti : Error< + "cannot use dynamic_cast with -fno-rtti">; def err_cannot_form_pointer_to_member_of_reference_type : Error< "cannot form a pointer-to-member to member %0 of reference type %1">; diff --git a/lib/Sema/SemaCast.cpp b/lib/Sema/SemaCast.cpp index 1adb037..888c14e 100644 --- a/lib/Sema/SemaCast.cpp +++ b/lib/Sema/SemaCast.cpp @@ -667,6 +667,13 @@ void CastOperation::CheckDynamicCast() { Self.MarkVTableUsed(OpRange.getBegin(), cast<CXXRecordDecl>(SrcRecord->getDecl())); + // dynamic_cast is not available with fno-rtti + if (!Self.getLangOpts().RTTI) { + Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti); + SrcExpr = ExprError(); + return; + } + // Done. Everything else is run-time checks. Kind = CK_Dynamic; } diff --git a/test/SemaCXX/dynamic_cast-no-rtti.cpp b/test/SemaCXX/dynamic_cast-no-rtti.cpp new file mode 100644 index 0000000..03f7b42 --- /dev/null +++ b/test/SemaCXX/dynamic_cast-no-rtti.cpp @@ -0,0 +1,22 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -fno-rtti %s +// expected-no-diagnostics + +namespace { +struct A { + virtual ~A(){}; +}; + +struct B : public A { + B() : A() {} +}; +} + +// Upcasts are resolved statically and will not require runtime support. +A *upcast(B *b) { + return dynamic_cast<A *>(b); +} + +// The dynamic_cast is a NoOp here and will not require runtime support. +B *samecast(B *b) { + return dynamic_cast<B *>(b); +} diff --git a/test/SemaCXX/no-rtti.cpp b/test/SemaCXX/no-rtti.cpp index 75167050..3d6e109 100644 --- a/test/SemaCXX/no-rtti.cpp +++ b/test/SemaCXX/no-rtti.cpp @@ -8,3 +8,17 @@ void f() { (void)typeid(int); // expected-error {{cannot use typeid with -fno-rtti}} } + +namespace { +struct A { + virtual ~A(){}; +}; + +struct B : public A { + B() : A() {} +}; +} + +bool isa_B(A *a) { + return dynamic_cast<B *>(a) != 0; // expected-error {{cannot use dynamic_cast with -fno-rtti}} +} -- 1.8.1.5
_______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
