r275417 - Diagnose taking address and reference binding of packed members
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Thu Jul 14 17:28:57 PDT 2016
OK, actually, GCC is doing something a lot more clever here.
Here's what seems to really be going on:
Packed members are modeled somewhat like bitfield members: a packed member
lvalue is a different kind of lvalue to which a reference cannot be bound
(like a bitfield). An attempt to bind a const / rvalue reference to such a
member will create a temporary, copy the packed / bitfield member to the
temporary, and then bind the reference to the temporary.
If we want to follow GCC here (and I think we do -- this seems like a very
sensible model), we should handle this case as an ObjectKind and generally
apply the same semantic rules that we use for bitfields.
On Thu, Jul 14, 2016 at 5:18 PM, Richard Smith <richard at metafoo.co.uk>
wrote:
> It appears that GCC accepts that case. More generally, it looks like GCC
> suppresses the warning when the reference is a function parameter (any
> function, not just a copy constructor or similar). I'm not sure if that's
> an intentional feature or a bug, but it should be pretty easy for us to be
> compatible with, at least...
>
> On Thu, Jul 14, 2016 at 5:03 PM, Reid Kleckner <rnk at google.com> wrote:
>
>> I wonder if GCC accepts this:
>>
>> In file included from ../../net/tools/quic/quic_epoll_clock_test.cc:7:
>> In file included from
>> ../../net/tools/quic/test_tools/mock_epoll_server.h:16:
>> In file included from ../../net/tools/epoll_server/epoll_server.h:41:
>> ../../build/linux/debian_wheezy_amd64-sysroot/usr/include/x86_64-linux-gnu/sys/epoll.h:89:8:
>> error: binding reference to packed member 'data' of class or structure
>> 'epoll_event'
>> struct epoll_event
>> ^~~~~~~~~~~
>> ../../build/linux/debian_wheezy_amd64-sysroot/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../include/c++/4.6/bits/stl_pair.h:267:14:
>> note: in instantiation of function template specialization 'std::pair<long,
>> epoll_event>::pair<long, epoll_event>' requested here
>> return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y));
>> ^
>> ../../net/tools/quic/test_tools/mock_epoll_server.h:69:30: note: in
>> instantiation of function template specialization 'std::make_pair<long &,
>> const epoll_event &>' requested here
>> event_queue_.insert(std::make_pair(time_in_usec, ee));
>>
>> On Thu, Jul 14, 2016 at 4:54 PM, Richard Smith <richard at metafoo.co.uk>
>> wrote:
>>
>>> On Thu, Jul 14, 2016 at 3:52 PM, Reid Kleckner via cfe-commits <
>>> cfe-commits at lists.llvm.org> wrote:
>>>
>>>> Why did we upgrade the unaligned reference binding from a warning to an
>>>> error? That will make it hard to roll this change out across many codebases.
>>>>
>>>
>>> GCC has given an error on this since version 4.7. If there are cases
>>> that GCC accepts and we reject, that sounds like a bug.
>>>
>>>
>>>> On Thu, Jul 14, 2016 at 7:10 AM, Roger Ferrer Ibanez via cfe-commits <
>>>> cfe-commits at lists.llvm.org> wrote:
>>>>
>>>>> Author: rogfer01
>>>>> Date: Thu Jul 14 09:10:43 2016
>>>>> New Revision: 275417
>>>>>
>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=275417&view=rev
>>>>> Log:
>>>>> Diagnose taking address and reference binding of packed members
>>>>>
>>>>> This patch implements PR#22821.
>>>>>
>>>>> Taking the address of a packed member is dangerous since the reduced
>>>>> alignment of the pointee is lost. This can lead to memory alignment
>>>>> faults in some architectures if the pointer value is dereferenced.
>>>>>
>>>>> This change adds a new warning to clang emitted when taking the address
>>>>> of a packed member. A packed member is either a field/data member
>>>>> declared as attribute((packed)) or belonging to a struct/class
>>>>> declared as such. The associated flag is -Waddress-of-packed-member.
>>>>> Conversions (either implicit or via a valid casting) to pointer types
>>>>> with lower or equal alignment requirements (e.g. void* or char*)
>>>>> silence the warning.
>>>>>
>>>>> This change also adds a new error diagnostic when the user attempts to
>>>>> bind a reference to a packed member, regardless of the alignment.
>>>>>
>>>>> Differential Revision: https://reviews.llvm.org/D20561
>>>>>
>>>>>
>>>>>
>>>>> Added:
>>>>> cfe/trunk/test/Sema/address-packed-member-memops.c
>>>>> cfe/trunk/test/Sema/address-packed.c
>>>>> cfe/trunk/test/SemaCXX/address-packed-member-memops.cpp
>>>>> cfe/trunk/test/SemaCXX/address-packed.cpp
>>>>> Modified:
>>>>> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>>>> cfe/trunk/include/clang/Sema/Sema.h
>>>>> cfe/trunk/lib/Sema/SemaCast.cpp
>>>>> cfe/trunk/lib/Sema/SemaChecking.cpp
>>>>> cfe/trunk/lib/Sema/SemaExpr.cpp
>>>>> cfe/trunk/lib/Sema/SemaInit.cpp
>>>>>
>>>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=275417&r1=275416&r2=275417&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>>>>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Jul 14
>>>>> 09:10:43 2016
>>>>> @@ -5425,6 +5425,11 @@ def warn_pointer_indirection_from_incomp
>>>>> "dereference of type %1 that was reinterpret_cast from type %0 has
>>>>> undefined "
>>>>> "behavior">,
>>>>> InGroup<UndefinedReinterpretCast>, DefaultIgnore;
>>>>> +def warn_taking_address_of_packed_member : Warning<
>>>>> + "taking address of packed member %0 of class or structure %q1 may
>>>>> result in an unaligned pointer value">,
>>>>> + InGroup<DiagGroup<"address-of-packed-member">>;
>>>>> +def err_binding_reference_to_packed_member : Error<
>>>>> + "binding reference to packed member %0 of class or structure %q1">;
>>>>>
>>>>> def err_objc_object_assignment : Error<
>>>>> "cannot assign to class object (%0 invalid)">;
>>>>>
>>>>> Modified: cfe/trunk/include/clang/Sema/Sema.h
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=275417&r1=275416&r2=275417&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/include/clang/Sema/Sema.h (original)
>>>>> +++ cfe/trunk/include/clang/Sema/Sema.h Thu Jul 14 09:10:43 2016
>>>>> @@ -9518,6 +9518,10 @@ private:
>>>>> void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
>>>>> const Expr * const *ExprArgs);
>>>>>
>>>>> + /// \brief Check if we are taking the address of a packed field
>>>>> + /// as this may be a problem if the pointer value is dereferenced.
>>>>> + void CheckAddressOfPackedMember(Expr *rhs);
>>>>> +
>>>>> /// \brief The parser's current scope.
>>>>> ///
>>>>> /// The parser maintains this state here.
>>>>> @@ -9596,6 +9600,51 @@ public:
>>>>> // Emitting members of dllexported classes is delayed until the
>>>>> class
>>>>> // (including field initializers) is fully parsed.
>>>>> SmallVector<CXXRecordDecl*, 4> DelayedDllExportClasses;
>>>>> +
>>>>> +private:
>>>>> + /// \brief Helper class that collects misaligned member
>>>>> designations and
>>>>> + /// their location info for delayed diagnostics.
>>>>> + struct MisalignedMember {
>>>>> + Expr *E;
>>>>> + RecordDecl *RD;
>>>>> + ValueDecl *MD;
>>>>> + CharUnits Alignment;
>>>>> +
>>>>> + MisalignedMember() : E(), RD(), MD(), Alignment() {}
>>>>> + MisalignedMember(Expr *E, RecordDecl *RD, ValueDecl *MD,
>>>>> + CharUnits Alignment)
>>>>> + : E(E), RD(RD), MD(MD), Alignment(Alignment) {}
>>>>> + explicit MisalignedMember(Expr *E)
>>>>> + : MisalignedMember(E, nullptr, nullptr, CharUnits()) {}
>>>>> +
>>>>> + bool operator==(const MisalignedMember &m) { return this->E ==
>>>>> m.E; }
>>>>> + };
>>>>> + /// \brief Small set of gathered accesses to potentially misaligned
>>>>> members
>>>>> + /// due to the packed attribute.
>>>>> + SmallVector<MisalignedMember, 4> MisalignedMembers;
>>>>> +
>>>>> + /// \brief Adds an expression to the set of gathered misaligned
>>>>> members.
>>>>> + void AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD,
>>>>> ValueDecl *MD,
>>>>> + CharUnits Alignment);
>>>>> +
>>>>> +public:
>>>>> + /// \brief Diagnoses the current set of gathered accesses. This
>>>>> typically
>>>>> + /// happens at full expression level. The set is cleared after
>>>>> emitting the
>>>>> + /// diagnostics.
>>>>> + void DiagnoseMisalignedMembers();
>>>>> +
>>>>> + /// \brief This function checks if the expression is in the sef of
>>>>> potentially
>>>>> + /// misaligned members and it is converted to some pointer type T
>>>>> with lower
>>>>> + /// or equal alignment requirements. If so it removes it. This is
>>>>> used when
>>>>> + /// we do not want to diagnose such misaligned access (e.g. in
>>>>> conversions to void*).
>>>>> + void DiscardMisalignedMemberAddress(const Type *T, Expr *E);
>>>>> +
>>>>> + /// \brief This function calls Action when it determines that E
>>>>> designates a
>>>>> + /// misaligned member due to the packed attribute. This is used to
>>>>> emit
>>>>> + /// local diagnostics like in reference binding.
>>>>> + void RefersToMemberWithReducedAlignment(
>>>>> + Expr *E,
>>>>> + std::function<void(Expr *, RecordDecl *, ValueDecl *,
>>>>> CharUnits)> Action);
>>>>> };
>>>>>
>>>>> /// \brief RAII object that enters a new expression evaluation
>>>>> context.
>>>>>
>>>>> Modified: cfe/trunk/lib/Sema/SemaCast.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCast.cpp?rev=275417&r1=275416&r2=275417&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/lib/Sema/SemaCast.cpp (original)
>>>>> +++ cfe/trunk/lib/Sema/SemaCast.cpp Thu Jul 14 09:10:43 2016
>>>>> @@ -256,6 +256,7 @@ Sema::BuildCXXNamedCast(SourceLocation O
>>>>> Op.CheckConstCast();
>>>>> if (Op.SrcExpr.isInvalid())
>>>>> return ExprError();
>>>>> + DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
>>>>> }
>>>>> return Op.complete(CXXConstCastExpr::Create(Context,
>>>>> Op.ResultType,
>>>>> Op.ValueKind, Op.SrcExpr.get(),
>>>>> DestTInfo,
>>>>> @@ -279,6 +280,7 @@ Sema::BuildCXXNamedCast(SourceLocation O
>>>>> Op.CheckReinterpretCast();
>>>>> if (Op.SrcExpr.isInvalid())
>>>>> return ExprError();
>>>>> + DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
>>>>> }
>>>>> return Op.complete(CXXReinterpretCastExpr::Create(Context,
>>>>> Op.ResultType,
>>>>> Op.ValueKind, Op.Kind,
>>>>> Op.SrcExpr.get(),
>>>>> @@ -291,6 +293,7 @@ Sema::BuildCXXNamedCast(SourceLocation O
>>>>> Op.CheckStaticCast();
>>>>> if (Op.SrcExpr.isInvalid())
>>>>> return ExprError();
>>>>> + DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
>>>>> }
>>>>>
>>>>> return Op.complete(CXXStaticCastExpr::Create(Context,
>>>>> Op.ResultType,
>>>>>
>>>>> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=275417&r1=275416&r2=275417&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>>>>> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Thu Jul 14 09:10:43 2016
>>>>> @@ -8302,6 +8302,8 @@ void CheckImplicitConversion(Sema &S, Ex
>>>>>
>>>>> DiagnoseNullConversion(S, E, T, CC);
>>>>>
>>>>> + S.DiscardMisalignedMemberAddress(Target, E);
>>>>> +
>>>>> if (!Source->isIntegerType() || !Target->isIntegerType())
>>>>> return;
>>>>>
>>>>> @@ -9371,6 +9373,7 @@ void Sema::CheckCompletedExpr(Expr *E, S
>>>>> CheckUnsequencedOperations(E);
>>>>> if (!IsConstexpr && !E->isValueDependent())
>>>>> CheckForIntOverflow(E);
>>>>> + DiagnoseMisalignedMembers();
>>>>> }
>>>>>
>>>>> void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
>>>>> @@ -10916,3 +10919,67 @@ void Sema::CheckArgumentWithTypeTag(cons
>>>>> << ArgumentExpr->getSourceRange()
>>>>> << TypeTagExpr->getSourceRange();
>>>>> }
>>>>> +
>>>>> +void Sema::AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD,
>>>>> ValueDecl *MD,
>>>>> + CharUnits Alignment) {
>>>>> + MisalignedMembers.emplace_back(E, RD, MD, Alignment);
>>>>> +}
>>>>> +
>>>>> +void Sema::DiagnoseMisalignedMembers() {
>>>>> + for (MisalignedMember &m : MisalignedMembers) {
>>>>> + Diag(m.E->getLocStart(),
>>>>> diag::warn_taking_address_of_packed_member)
>>>>> + << m.MD << m.RD << m.E->getSourceRange();
>>>>> + }
>>>>> + MisalignedMembers.clear();
>>>>> +}
>>>>> +
>>>>> +void Sema::DiscardMisalignedMemberAddress(const Type *T, Expr *E) {
>>>>> + if (!T->isPointerType())
>>>>> + return;
>>>>> + if (isa<UnaryOperator>(E) &&
>>>>> + cast<UnaryOperator>(E)->getOpcode() == UO_AddrOf) {
>>>>> + auto *Op = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
>>>>> + if (isa<MemberExpr>(Op)) {
>>>>> + auto MA = std::find(MisalignedMembers.begin(),
>>>>> MisalignedMembers.end(),
>>>>> + MisalignedMember(Op));
>>>>> + if (MA != MisalignedMembers.end() &&
>>>>> + Context.getTypeAlignInChars(T->getPointeeType()) <=
>>>>> MA->Alignment)
>>>>> + MisalignedMembers.erase(MA);
>>>>> + }
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +void Sema::RefersToMemberWithReducedAlignment(
>>>>> + Expr *E,
>>>>> + std::function<void(Expr *, RecordDecl *, ValueDecl *, CharUnits)>
>>>>> Action) {
>>>>> + const auto *ME = dyn_cast<MemberExpr>(E);
>>>>> + while (ME && isa<FieldDecl>(ME->getMemberDecl())) {
>>>>> + QualType BaseType = ME->getBase()->getType();
>>>>> + if (ME->isArrow())
>>>>> + BaseType = BaseType->getPointeeType();
>>>>> + RecordDecl *RD = BaseType->getAs<RecordType>()->getDecl();
>>>>> +
>>>>> + ValueDecl *MD = ME->getMemberDecl();
>>>>> + bool ByteAligned =
>>>>> Context.getTypeAlignInChars(MD->getType()).isOne();
>>>>> + if (ByteAligned) // Attribute packed does not have any effect.
>>>>> + break;
>>>>> +
>>>>> + if (!ByteAligned &&
>>>>> + (RD->hasAttr<PackedAttr>() || (MD->hasAttr<PackedAttr>()))) {
>>>>> + CharUnits Alignment =
>>>>> std::min(Context.getTypeAlignInChars(MD->getType()),
>>>>> +
>>>>> Context.getTypeAlignInChars(BaseType));
>>>>> + // Notify that this expression designates a member with reduced
>>>>> alignment
>>>>> + Action(E, RD, MD, Alignment);
>>>>> + break;
>>>>> + }
>>>>> + ME = dyn_cast<MemberExpr>(ME->getBase());
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +void Sema::CheckAddressOfPackedMember(Expr *rhs) {
>>>>> + using namespace std::placeholders;
>>>>> + RefersToMemberWithReducedAlignment(
>>>>> + rhs, std::bind(&Sema::AddPotentialMisalignedMembers,
>>>>> std::ref(*this), _1,
>>>>> + _2, _3, _4));
>>>>> +}
>>>>> +
>>>>>
>>>>> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=275417&r1=275416&r2=275417&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
>>>>> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Thu Jul 14 09:10:43 2016
>>>>> @@ -6001,7 +6001,9 @@ Sema::ActOnCastExpr(Scope *S, SourceLoca
>>>>> CheckTollFreeBridgeCast(castType, CastExpr);
>>>>>
>>>>> CheckObjCBridgeRelatedCast(castType, CastExpr);
>>>>> -
>>>>> +
>>>>> + DiscardMisalignedMemberAddress(castType.getTypePtr(), CastExpr);
>>>>> +
>>>>> return BuildCStyleCastExpr(LParenLoc, castTInfo, RParenLoc,
>>>>> CastExpr);
>>>>> }
>>>>>
>>>>> @@ -10534,6 +10536,8 @@ QualType Sema::CheckAddressOfOperand(Exp
>>>>> if (op->getType()->isObjCObjectType())
>>>>> return Context.getObjCObjectPointerType(op->getType());
>>>>>
>>>>> + CheckAddressOfPackedMember(op);
>>>>> +
>>>>> return Context.getPointerType(op->getType());
>>>>> }
>>>>>
>>>>>
>>>>> Modified: cfe/trunk/lib/Sema/SemaInit.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=275417&r1=275416&r2=275417&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/lib/Sema/SemaInit.cpp (original)
>>>>> +++ cfe/trunk/lib/Sema/SemaInit.cpp Thu Jul 14 09:10:43 2016
>>>>> @@ -6457,6 +6457,15 @@ InitializationSequence::Perform(Sema &S,
>>>>> ExtendingEntity->getDecl());
>>>>>
>>>>> CheckForNullPointerDereference(S, CurInit.get());
>>>>> +
>>>>> + S.RefersToMemberWithReducedAlignment(CurInit.get(), [&](Expr *E,
>>>>> +
>>>>> RecordDecl *RD,
>>>>> +
>>>>> ValueDecl *MD,
>>>>> +
>>>>> CharUnits) {
>>>>> + S.Diag(Kind.getLocation(),
>>>>> diag::err_binding_reference_to_packed_member)
>>>>> + << MD << RD << E->getSourceRange();
>>>>> + });
>>>>> +
>>>>> break;
>>>>>
>>>>> case SK_BindReferenceToTemporary: {
>>>>> @@ -6645,12 +6654,16 @@ InitializationSequence::Perform(Sema &S,
>>>>> getAssignmentAction(Entity), CCK);
>>>>> if (CurInitExprRes.isInvalid())
>>>>> return ExprError();
>>>>> +
>>>>> + S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(),
>>>>> CurInit.get());
>>>>> +
>>>>> CurInit = CurInitExprRes;
>>>>>
>>>>> if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
>>>>> S.getLangOpts().CPlusPlus &&
>>>>> !CurInit.get()->isValueDependent())
>>>>> DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType,
>>>>> Entity.getType(),
>>>>> CurInit.get());
>>>>> +
>>>>> break;
>>>>> }
>>>>>
>>>>>
>>>>> Added: cfe/trunk/test/Sema/address-packed-member-memops.c
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/address-packed-member-memops.c?rev=275417&view=auto
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/test/Sema/address-packed-member-memops.c (added)
>>>>> +++ cfe/trunk/test/Sema/address-packed-member-memops.c Thu Jul 14
>>>>> 09:10:43 2016
>>>>> @@ -0,0 +1,26 @@
>>>>> +// RUN: %clang_cc1 -fsyntax-only -verify %s
>>>>> +// expected-no-diagnostics
>>>>> +
>>>>> +struct B {
>>>>> + int x, y, z, w;
>>>>> +} b;
>>>>> +
>>>>> +struct __attribute__((packed)) A {
>>>>> + struct B b;
>>>>> +} a;
>>>>> +
>>>>> +typedef __typeof__(sizeof(int)) size_t;
>>>>> +
>>>>> +void *memcpy(void *dest, const void *src, size_t n);
>>>>> +int memcmp(const void *s1, const void *s2, size_t n);
>>>>> +void *memmove(void *dest, const void *src, size_t n);
>>>>> +void *memset(void *s, int c, size_t n);
>>>>> +
>>>>> +int x;
>>>>> +
>>>>> +void foo(void) {
>>>>> + memcpy(&a.b, &b, sizeof(b));
>>>>> + memmove(&a.b, &b, sizeof(b));
>>>>> + memset(&a.b, 0, sizeof(b));
>>>>> + x = memcmp(&a.b, &b, sizeof(b));
>>>>> +}
>>>>>
>>>>> Added: cfe/trunk/test/Sema/address-packed.c
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/address-packed.c?rev=275417&view=auto
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/test/Sema/address-packed.c (added)
>>>>> +++ cfe/trunk/test/Sema/address-packed.c Thu Jul 14 09:10:43 2016
>>>>> @@ -0,0 +1,160 @@
>>>>> +// RUN: %clang_cc1 -fsyntax-only -verify %s
>>>>> +extern void f1(int *);
>>>>> +extern void f2(char *);
>>>>> +
>>>>> +struct Ok {
>>>>> + char c;
>>>>> + int x;
>>>>> +};
>>>>> +
>>>>> +struct __attribute__((packed)) Arguable {
>>>>> + char c0;
>>>>> + int x;
>>>>> + char c1;
>>>>> +};
>>>>> +
>>>>> +union __attribute__((packed)) UnionArguable {
>>>>> + char c;
>>>>> + int x;
>>>>> +};
>>>>> +
>>>>> +typedef struct Arguable ArguableT;
>>>>> +
>>>>> +struct Arguable *get_arguable();
>>>>> +
>>>>> +void to_void(void *);
>>>>> +
>>>>> +void g0(void) {
>>>>> + {
>>>>> + struct Ok ok;
>>>>> + f1(&ok.x); // no-warning
>>>>> + f2(&ok.c); // no-warning
>>>>> + }
>>>>> + {
>>>>> + struct Arguable arguable;
>>>>> + f2(&arguable.c0); // no-warning
>>>>> + f1(&arguable.x); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Arguable'}}
>>>>> + f2(&arguable.c1); // no-warning
>>>>> +
>>>>> + f1((int *)(void *)&arguable.x); // no-warning
>>>>> + to_void(&arguable.x); // no-warning
>>>>> + void *p = &arguable.x; // no-warning;
>>>>> + to_void(p);
>>>>> + }
>>>>> + {
>>>>> + union UnionArguable arguable;
>>>>> + f2(&arguable.c); // no-warning
>>>>> + f1(&arguable.x); // expected-warning {{packed member 'x' of class
>>>>> or structure 'UnionArguable'}}
>>>>> +
>>>>> + f1((int *)(void *)&arguable.x); // no-warning
>>>>> + to_void(&arguable.x); // no-warning
>>>>> + }
>>>>> + {
>>>>> + ArguableT arguable;
>>>>> + f2(&arguable.c0); // no-warning
>>>>> + f1(&arguable.x); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Arguable'}}
>>>>> + f2(&arguable.c1); // no-warning
>>>>> +
>>>>> + f1((int *)(void *)&arguable.x); // no-warning
>>>>> + to_void(&arguable.x); // no-warning
>>>>> + }
>>>>> + {
>>>>> + struct Arguable *arguable = get_arguable();
>>>>> + f2(&arguable->c0); // no-warning
>>>>> + f1(&arguable->x); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Arguable'}}
>>>>> + f2(&arguable->c1); // no-warning
>>>>> +
>>>>> + f1((int *)(void *)&arguable->x); // no-warning
>>>>> + to_void(&arguable->c1); // no-warning
>>>>> + }
>>>>> + {
>>>>> + ArguableT *arguable = get_arguable();
>>>>> + f2(&(arguable->c0)); // no-warning
>>>>> + f1(&(arguable->x)); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Arguable'}}
>>>>> + f2(&(arguable->c1)); // no-warning
>>>>> +
>>>>> + f1((int *)(void *)&(arguable->x)); // no-warning
>>>>> + to_void(&(arguable->c1)); // no-warning
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +struct S1 {
>>>>> + char c;
>>>>> + int i __attribute__((packed));
>>>>> +};
>>>>> +
>>>>> +int *g1(struct S1 *s1) {
>>>>> + return &s1->i; // expected-warning {{packed member 'i' of class or
>>>>> structure 'S1'}}
>>>>> +}
>>>>> +
>>>>> +struct S2_i {
>>>>> + int i;
>>>>> +};
>>>>> +struct __attribute__((packed)) S2 {
>>>>> + char c;
>>>>> + struct S2_i inner;
>>>>> +};
>>>>> +
>>>>> +int *g2(struct S2 *s2) {
>>>>> + return &s2->inner.i; // expected-warning {{packed member 'inner' of
>>>>> class or structure 'S2'}}
>>>>> +}
>>>>> +
>>>>> +struct S2_a {
>>>>> + char c;
>>>>> + struct S2_i inner __attribute__((packed));
>>>>> +};
>>>>> +
>>>>> +int *g2_a(struct S2_a *s2_a) {
>>>>> + return &s2_a->inner.i; // expected-warning {{packed member 'inner'
>>>>> of class or structure 'S2_a'}}
>>>>> +}
>>>>> +
>>>>> +struct __attribute__((packed)) S3 {
>>>>> + char c;
>>>>> + struct {
>>>>> + int i;
>>>>> + } inner;
>>>>> +};
>>>>> +
>>>>> +int *g3(struct S3 *s3) {
>>>>> + return &s3->inner.i; // expected-warning {{packed member 'inner' of
>>>>> class or structure 'S3'}}
>>>>> +}
>>>>> +
>>>>> +struct S4 {
>>>>> + char c;
>>>>> + struct __attribute__((packed)) {
>>>>> + int i;
>>>>> + } inner;
>>>>> +};
>>>>> +
>>>>> +int *g4(struct S4 *s4) {
>>>>> + return &s4->inner.i; // expected-warning {{packed member 'i' of
>>>>> class or structure 'S4::(anonymous)'}}
>>>>> +}
>>>>> +
>>>>> +struct S5 {
>>>>> + char c;
>>>>> + struct {
>>>>> + char c1;
>>>>> + int i __attribute__((packed));
>>>>> + } inner;
>>>>> +};
>>>>> +
>>>>> +int *g5(struct S5 *s5) {
>>>>> + return &s5->inner.i; // expected-warning {{packed member 'i' of
>>>>> class or structure 'S5::(anonymous)'}}
>>>>> +}
>>>>> +
>>>>> +struct __attribute__((packed, aligned(2))) AlignedTo2 {
>>>>> + int x;
>>>>> +};
>>>>> +
>>>>> +char *g6(struct AlignedTo2 *s) {
>>>>> + return (char *)&s->x; // no-warning
>>>>> +}
>>>>> +
>>>>> +struct __attribute__((packed, aligned(2))) AlignedTo2Bis {
>>>>> + int x;
>>>>> +};
>>>>> +
>>>>> +struct AlignedTo2Bis* g7(struct AlignedTo2 *s)
>>>>> +{
>>>>> + return (struct AlignedTo2Bis*)&s->x; // no-warning
>>>>> +}
>>>>>
>>>>> Added: cfe/trunk/test/SemaCXX/address-packed-member-memops.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/address-packed-member-memops.cpp?rev=275417&view=auto
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/test/SemaCXX/address-packed-member-memops.cpp (added)
>>>>> +++ cfe/trunk/test/SemaCXX/address-packed-member-memops.cpp Thu Jul 14
>>>>> 09:10:43 2016
>>>>> @@ -0,0 +1,28 @@
>>>>> +// RUN: %clang_cc1 -fsyntax-only -verify %s
>>>>> +// expected-no-diagnostics
>>>>> +
>>>>> +struct B {
>>>>> + int x, y, z, w;
>>>>> +} b;
>>>>> +
>>>>> +struct __attribute__((packed)) A {
>>>>> + struct B b;
>>>>> +} a;
>>>>> +
>>>>> +typedef __typeof__(sizeof(int)) size_t;
>>>>> +
>>>>> +extern "C" {
>>>>> +void *memcpy(void *dest, const void *src, size_t n);
>>>>> +int memcmp(const void *s1, const void *s2, size_t n);
>>>>> +void *memmove(void *dest, const void *src, size_t n);
>>>>> +void *memset(void *s, int c, size_t n);
>>>>> +}
>>>>> +
>>>>> +int x;
>>>>> +
>>>>> +void foo() {
>>>>> + memcpy(&a.b, &b, sizeof(b));
>>>>> + memmove(&a.b, &b, sizeof(b));
>>>>> + memset(&a.b, 0, sizeof(b));
>>>>> + x = memcmp(&a.b, &b, sizeof(b));
>>>>> +}
>>>>>
>>>>> Added: cfe/trunk/test/SemaCXX/address-packed.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/address-packed.cpp?rev=275417&view=auto
>>>>>
>>>>> ==============================================================================
>>>>> --- cfe/trunk/test/SemaCXX/address-packed.cpp (added)
>>>>> +++ cfe/trunk/test/SemaCXX/address-packed.cpp Thu Jul 14 09:10:43 2016
>>>>> @@ -0,0 +1,118 @@
>>>>> +// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
>>>>> +extern void f1(int *);
>>>>> +extern void f2(char *);
>>>>> +
>>>>> +struct __attribute__((packed)) Arguable {
>>>>> + int x;
>>>>> + char c;
>>>>> + static void foo();
>>>>> +};
>>>>> +
>>>>> +extern void f3(void());
>>>>> +
>>>>> +namespace Foo {
>>>>> +struct __attribute__((packed)) Arguable {
>>>>> + char c;
>>>>> + int x;
>>>>> + static void foo();
>>>>> +};
>>>>> +}
>>>>> +
>>>>> +struct Arguable *get_arguable();
>>>>> +
>>>>> +void f4(int &);
>>>>> +
>>>>> +void to_void(void *);
>>>>> +
>>>>> +template <typename... T>
>>>>> +void sink(T...);
>>>>> +
>>>>> +void g0() {
>>>>> + {
>>>>> + Foo::Arguable arguable;
>>>>> + f1(&arguable.x); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Foo::Arguable'}}
>>>>> + f2(&arguable.c); // no-warning
>>>>> + f3(&arguable.foo); // no-warning
>>>>> +
>>>>> + int &w = arguable.x; // expected-error {{binding reference to
>>>>> packed member 'x' of class or structure 'Foo::Arguable'}}
>>>>> + sink(w);
>>>>> + f4(arguable.x); // expected-error {{binding reference to packed
>>>>> member 'x' of class or structure 'Foo::Arguable'}}
>>>>> +
>>>>> + to_void(&arguable.x); // no-warning
>>>>> + void *p1 = &arguable.x; // no-warning
>>>>> + void *p2 = static_cast<void *>(&arguable.x); // no-warning
>>>>> + void *p3 = reinterpret_cast<void *>(&arguable.x); // no-warning
>>>>> + void *p4 = (void *)&arguable.x; // no-warning
>>>>> + sink(p1, p2, p3, p4);
>>>>> + }
>>>>> + {
>>>>> + Arguable arguable1;
>>>>> + Arguable &arguable(arguable1);
>>>>> + f1(&arguable.x); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Arguable'}}
>>>>> + f2(&arguable.c); // no-warning
>>>>> + f3(&arguable.foo); // no-warning
>>>>> + }
>>>>> + {
>>>>> + Arguable *arguable1;
>>>>> + Arguable *&arguable(arguable1);
>>>>> + f1(&arguable->x); // expected-warning {{packed member 'x' of
>>>>> class or structure 'Arguable'}}
>>>>> + f2(&arguable->c); // no-warning
>>>>> + f3(&arguable->foo); // no-warning
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +struct __attribute__((packed)) A {
>>>>> + int x;
>>>>> + char c;
>>>>> +
>>>>> + int *f0() {
>>>>> + return &this->x; // expected-warning {{packed member 'x' of class
>>>>> or structure 'A'}}
>>>>> + }
>>>>> +
>>>>> + int *g0() {
>>>>> + return &x; // expected-warning {{packed member 'x' of class or
>>>>> structure 'A'}}
>>>>> + }
>>>>> +
>>>>> + char *h0() {
>>>>> + return &c; // no-warning
>>>>> + }
>>>>> +};
>>>>> +
>>>>> +struct B : A {
>>>>> + int *f1() {
>>>>> + return &this->x; // expected-warning {{packed member 'x' of class
>>>>> or structure 'A'}}
>>>>> + }
>>>>> +
>>>>> + int *g1() {
>>>>> + return &x; // expected-warning {{packed member 'x' of class or
>>>>> structure 'A'}}
>>>>> + }
>>>>> +
>>>>> + char *h1() {
>>>>> + return &c; // no-warning
>>>>> + }
>>>>> +};
>>>>> +
>>>>> +template <typename Ty>
>>>>> +class __attribute__((packed)) S {
>>>>> + Ty X;
>>>>> +
>>>>> +public:
>>>>> + const Ty *get() const {
>>>>> + return &X; // expected-warning {{packed member 'X' of class or
>>>>> structure 'S<int>'}}
>>>>> + // expected-warning at -1 {{packed member 'X' of class
>>>>> or structure 'S<float>'}}
>>>>> + }
>>>>> +};
>>>>> +
>>>>> +template <typename Ty>
>>>>> +void h(Ty *);
>>>>> +
>>>>> +void g1() {
>>>>> + S<int> s1;
>>>>> + s1.get(); // expected-note {{in instantiation of member function
>>>>> 'S<int>::get'}}
>>>>> +
>>>>> + S<char> s2;
>>>>> + s2.get();
>>>>> +
>>>>> + S<float> s3;
>>>>> + s3.get(); // expected-note {{in instantiation of member function
>>>>> 'S<float>::get'}}
>>>>> +}
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> cfe-commits mailing list
>>>>> cfe-commits at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> cfe-commits mailing list
>>>> cfe-commits at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>>>
>>>>
>>>
>>
>
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