r369591 - [LifetimeAnalysis] Support more STL idioms (template forward declaration and DependentNameType)
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Fri Aug 23 13:03:14 PDT 2019
On Thu, 22 Aug 2019 at 13:05, Matthias Gehre via cfe-commits <
cfe-commits at lists.llvm.org> wrote:
> Hi Diana,
> hi Richard,
>
> thank you for the feedback!
>
> Diana,
> I remember that some gcc version had issues with raw string literals
> inside macros. I'll fix that to use normal
> string literals instead.
>
> Richard,
> We are definitely want the gsl::Pointer-based warnings that are enabled by
> default to be free of any false-positives.
> As you expected, this is showing a problem we have in another part of our
> analysis, and we will fix it before landing
> this PR again.
>
It looks like this revert wasn't enough to unblock us. We're currently
unable to release compilers due to the scale of the new enabled-by-default
diagnostics produced by these warnings, and we're not happy about turning
off the existing (zero false positives) warning flags here in order to
unblock our releases, because they're so valuable in catching errors. I'd
expect others will hit similar issues when upgrading Clang. Even if there
were no false positives in the new warning, it appears to be undeployable
as-is because the new warning is behind the same warning flag as an
existing high-value warning. So I think we need the new warnings to be
moved behind different warning flags (a subgroup of ReturnStackAddress
would be OK, but it needs to be independently controllable).
If this can be done imminently, that would be OK, but otherwise I think we
should temporarily roll this back until it can be moved to a separate
warning group.
Both, sorry for the breakage!
>
> Am Do., 22. Aug. 2019 um 19:47 Uhr schrieb Richard Smith <
> richard at metafoo.co.uk>:
>
>> Reverted in r369677.
>>
>> On Thu, 22 Aug 2019 at 10:34, Richard Smith <richard at metafoo.co.uk>
>> wrote:
>>
>>> Hi Matthias,
>>>
>>> This introduces false positives into -Wreturn-stack-address for an
>>> example such as:
>>>
>>> #include <vector>
>>>
>>> std::vector<int>::iterator downcast_to(std::vector<int>::iterator value)
>>> {
>>> return *&value;
>>> }
>>>
>>> This breaks an internal build bot for us, so I'm going to revert this
>>> for now (though I expect this isn't the cause of the problem, but is rather
>>> exposing a problem elsewhere).
>>>
>>> If we can make the gsl::Pointer diagnostics false-positive-free, that's
>>> great, but otherwise we should use a different warning flag for the
>>> warnings that involve these annotations and use -Wreturn-stack-address for
>>> only the zero-false-positive cases that it historically diagnosed.
>>>
>>> Thanks, and sorry for the trouble.
>>>
>>> On Wed, 21 Aug 2019 at 15:07, Matthias Gehre via cfe-commits <
>>> cfe-commits at lists.llvm.org> wrote:
>>>
>>>> Author: mgehre
>>>> Date: Wed Aug 21 15:08:59 2019
>>>> New Revision: 369591
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=369591&view=rev
>>>> Log:
>>>> [LifetimeAnalysis] Support more STL idioms (template forward
>>>> declaration and DependentNameType)
>>>>
>>>> Summary:
>>>> This fixes inference of gsl::Pointer on std::set::iterator with
>>>> libstdc++ (the typedef for iterator
>>>> on the template is a DependentNameType - we can only put the
>>>> gsl::Pointer attribute
>>>> on the underlaying record after instantiation)
>>>>
>>>> inference of gsl::Pointer on std::vector::iterator with libc++ (the
>>>> class was forward-declared,
>>>> we added the gsl::Pointer on the canonical decl (the forward decl), and
>>>> later when the
>>>> template was instantiated, there was no attribute on the definition so
>>>> it was not instantiated).
>>>>
>>>> and a duplicate gsl::Pointer on some class with libstdc++ (we first
>>>> added an attribute to
>>>> a incomplete instantiation, and then another was copied from the
>>>> template definition
>>>> when the instantiation was completed).
>>>>
>>>> We now add the attributes to all redeclarations to fix thos issues and
>>>> make their usage easier.
>>>>
>>>> Reviewers: gribozavr
>>>>
>>>> Subscribers: Szelethus, xazax.hun, cfe-commits
>>>>
>>>> Tags: #clang
>>>>
>>>> Differential Revision: https://reviews.llvm.org/D66179
>>>>
>>>> Added:
>>>> cfe/trunk/unittests/Sema/GslOwnerPointerInference.cpp
>>>> Modified:
>>>> cfe/trunk/lib/Sema/SemaAttr.cpp
>>>> cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>>>> cfe/trunk/lib/Sema/SemaInit.cpp
>>>> cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
>>>> cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer-std.cpp
>>>> cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer.cpp
>>>> cfe/trunk/unittests/Sema/CMakeLists.txt
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaAttr.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaAttr.cpp?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Sema/SemaAttr.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaAttr.cpp Wed Aug 21 15:08:59 2019
>>>> @@ -88,13 +88,11 @@ void Sema::AddMsStructLayoutForRecord(Re
>>>> template <typename Attribute>
>>>> static void addGslOwnerPointerAttributeIfNotExisting(ASTContext
>>>> &Context,
>>>> CXXRecordDecl
>>>> *Record) {
>>>> - CXXRecordDecl *Canonical = Record->getCanonicalDecl();
>>>> - if (Canonical->hasAttr<OwnerAttr>() ||
>>>> Canonical->hasAttr<PointerAttr>())
>>>> + if (Record->hasAttr<OwnerAttr>() || Record->hasAttr<PointerAttr>())
>>>> return;
>>>>
>>>> - Canonical->addAttr(::new (Context) Attribute(SourceRange{}, Context,
>>>> - /*DerefType*/ nullptr,
>>>> - /*Spelling=*/0));
>>>> + for (Decl *Redecl : Record->redecls())
>>>> + Redecl->addAttr(Attribute::CreateImplicit(Context,
>>>> /*DerefType=*/nullptr));
>>>> }
>>>>
>>>> void Sema::inferGslPointerAttribute(NamedDecl *ND,
>>>> @@ -189,8 +187,7 @@ void Sema::inferGslOwnerPointerAttribute
>>>>
>>>> // Handle classes that directly appear in std namespace.
>>>> if (Record->isInStdNamespace()) {
>>>> - CXXRecordDecl *Canonical = Record->getCanonicalDecl();
>>>> - if (Canonical->hasAttr<OwnerAttr>() ||
>>>> Canonical->hasAttr<PointerAttr>())
>>>> + if (Record->hasAttr<OwnerAttr>() || Record->hasAttr<PointerAttr>())
>>>> return;
>>>>
>>>> if (StdOwners.count(Record->getName()))
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Wed Aug 21 15:08:59 2019
>>>> @@ -4592,9 +4592,11 @@ static void handleLifetimeCategoryAttr(S
>>>> }
>>>> return;
>>>> }
>>>> - D->addAttr(::new (S.Context)
>>>> - OwnerAttr(AL.getRange(), S.Context, DerefTypeLoc,
>>>> - AL.getAttributeSpellingListIndex()));
>>>> + for (Decl *Redecl : D->redecls()) {
>>>> + Redecl->addAttr(::new (S.Context)
>>>> + OwnerAttr(AL.getRange(), S.Context,
>>>> DerefTypeLoc,
>>>> +
>>>> AL.getAttributeSpellingListIndex()));
>>>> + }
>>>> } else {
>>>> if (checkAttrMutualExclusion<OwnerAttr>(S, D, AL))
>>>> return;
>>>> @@ -4609,9 +4611,11 @@ static void handleLifetimeCategoryAttr(S
>>>> }
>>>> return;
>>>> }
>>>> - D->addAttr(::new (S.Context)
>>>> - PointerAttr(AL.getRange(), S.Context, DerefTypeLoc,
>>>> - AL.getAttributeSpellingListIndex()));
>>>> + for (Decl *Redecl : D->redecls()) {
>>>> + Redecl->addAttr(::new (S.Context)
>>>> + PointerAttr(AL.getRange(), S.Context,
>>>> DerefTypeLoc,
>>>> +
>>>> AL.getAttributeSpellingListIndex()));
>>>> + }
>>>> }
>>>> }
>>>>
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaInit.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Sema/SemaInit.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaInit.cpp Wed Aug 21 15:08:59 2019
>>>> @@ -6561,7 +6561,7 @@ static void visitLocalsRetainedByReferen
>>>>
>>>> template <typename T> static bool isRecordWithAttr(QualType Type) {
>>>> if (auto *RD = Type->getAsCXXRecordDecl())
>>>> - return RD->getCanonicalDecl()->hasAttr<T>();
>>>> + return RD->hasAttr<T>();
>>>> return false;
>>>> }
>>>>
>>>> @@ -6672,7 +6672,7 @@ static void handleGslAnnotatedTypes(Indi
>>>>
>>>> if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
>>>> const auto *Ctor = CCE->getConstructor();
>>>> - const CXXRecordDecl *RD = Ctor->getParent()->getCanonicalDecl();
>>>> + const CXXRecordDecl *RD = Ctor->getParent();
>>>> if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
>>>> VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0]);
>>>> }
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Wed Aug 21
>>>> 15:08:59 2019
>>>> @@ -552,6 +552,18 @@ void Sema::InstantiateAttrs(const MultiL
>>>> continue;
>>>> }
>>>>
>>>> + if (auto *A = dyn_cast<PointerAttr>(TmplAttr)) {
>>>> + if (!New->hasAttr<PointerAttr>())
>>>> + New->addAttr(A->clone(Context));
>>>> + continue;
>>>> + }
>>>> +
>>>> + if (auto *A = dyn_cast<OwnerAttr>(TmplAttr)) {
>>>> + if (!New->hasAttr<OwnerAttr>())
>>>> + New->addAttr(A->clone(Context));
>>>> + continue;
>>>> + }
>>>> +
>>>> assert(!TmplAttr->isPackExpansion());
>>>> if (TmplAttr->isLateParsed() && LateAttrs) {
>>>> // Late parsed attributes must be instantiated and attached
>>>> after the
>>>> @@ -711,6 +723,9 @@ Decl *TemplateDeclInstantiator::Instanti
>>>>
>>>> SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
>>>>
>>>> + if (D->getUnderlyingType()->getAs<DependentNameType>())
>>>> + SemaRef.inferGslPointerAttribute(Typedef);
>>>> +
>>>> Typedef->setAccess(D->getAccess());
>>>>
>>>> return Typedef;
>>>>
>>>> Modified: cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer-std.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer-std.cpp?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer-std.cpp (original)
>>>> +++ cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer-std.cpp Wed Aug 21
>>>> 15:08:59 2019
>>>> @@ -92,6 +92,59 @@ public:
>>>> static_assert(sizeof(unordered_map<int>::iterator), ""); // Force
>>>> instantiation.
>>>> } // namespace inlinens
>>>>
>>>> +// The iterator typedef is a DependentNameType.
>>>> +template <typename T>
>>>> +class __unordered_multimap_iterator {};
>>>> +// CHECK: ClassTemplateDecl {{.*}} __unordered_multimap_iterator
>>>> +// CHECK: ClassTemplateSpecializationDecl {{.*}}
>>>> __unordered_multimap_iterator
>>>> +// CHECK: TemplateArgument type 'int'
>>>> +// CHECK: PointerAttr
>>>> +
>>>> +template <typename T>
>>>> +class __unordered_multimap_base {
>>>> +public:
>>>> + using iterator = __unordered_multimap_iterator<T>;
>>>> +};
>>>> +
>>>> +template <typename T>
>>>> +class unordered_multimap {
>>>> + // CHECK: ClassTemplateDecl {{.*}} unordered_multimap
>>>> + // CHECK: OwnerAttr {{.*}}
>>>> + // CHECK: ClassTemplateSpecializationDecl {{.*}} unordered_multimap
>>>> + // CHECK: OwnerAttr {{.*}}
>>>> +public:
>>>> + using _Mybase = __unordered_multimap_base<T>;
>>>> + using iterator = typename _Mybase::iterator;
>>>> +};
>>>> +static_assert(sizeof(unordered_multimap<int>::iterator), ""); // Force
>>>> instantiation.
>>>> +
>>>> +// The canonical declaration of the iterator template is not its
>>>> definition.
>>>> +template <typename T>
>>>> +class __unordered_multiset_iterator;
>>>> +// CHECK: ClassTemplateDecl {{.*}} __unordered_multiset_iterator
>>>> +// CHECK: PointerAttr
>>>> +// CHECK: ClassTemplateSpecializationDecl {{.*}}
>>>> __unordered_multiset_iterator
>>>> +// CHECK: TemplateArgument type 'int'
>>>> +// CHECK: PointerAttr
>>>> +
>>>> +template <typename T>
>>>> +class __unordered_multiset_iterator {
>>>> + // CHECK: ClassTemplateDecl {{.*}} prev {{.*}}
>>>> __unordered_multiset_iterator
>>>> + // CHECK: PointerAttr
>>>> +};
>>>> +
>>>> +template <typename T>
>>>> +class unordered_multiset {
>>>> + // CHECK: ClassTemplateDecl {{.*}} unordered_multiset
>>>> + // CHECK: OwnerAttr {{.*}}
>>>> + // CHECK: ClassTemplateSpecializationDecl {{.*}} unordered_multiset
>>>> + // CHECK: OwnerAttr {{.*}}
>>>> +public:
>>>> + using iterator = __unordered_multiset_iterator<T>;
>>>> +};
>>>> +
>>>> +static_assert(sizeof(unordered_multiset<int>::iterator), ""); // Force
>>>> instantiation.
>>>> +
>>>> // std::list has an implicit gsl::Owner attribute,
>>>> // but explicit attributes take precedence.
>>>> template <typename T>
>>>>
>>>> Modified: cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer.cpp?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer.cpp (original)
>>>> +++ cfe/trunk/test/SemaCXX/attr-gsl-owner-pointer.cpp Wed Aug 21
>>>> 15:08:59 2019
>>>> @@ -105,3 +105,20 @@ class [[gsl::Owner(int)]] AddTheSameLate
>>>> class [[gsl::Owner(int)]] AddTheSameLater;
>>>> // CHECK: CXXRecordDecl {{.*}} prev {{.*}} AddTheSameLater
>>>> // CHECK: OwnerAttr {{.*}} int
>>>> +
>>>> +template <class T>
>>>> +class [[gsl::Owner]] ForwardDeclared;
>>>> +// CHECK: ClassTemplateDecl {{.*}} ForwardDeclared
>>>> +// CHECK: OwnerAttr {{.*}}
>>>> +// CHECK: ClassTemplateSpecializationDecl {{.*}} ForwardDeclared
>>>> +// CHECK: TemplateArgument type 'int'
>>>> +// CHECK: OwnerAttr {{.*}}
>>>> +
>>>> +template <class T>
>>>> +class [[gsl::Owner]] ForwardDeclared {
>>>> +// CHECK: ClassTemplateDecl {{.*}} ForwardDeclared
>>>> +// CHECK: CXXRecordDecl {{.*}} ForwardDeclared definition
>>>> +// CHECK: OwnerAttr {{.*}}
>>>> +};
>>>> +
>>>> +static_assert(sizeof(ForwardDeclared<int>), ""); // Force
>>>> instantiation.
>>>>
>>>> Modified: cfe/trunk/unittests/Sema/CMakeLists.txt
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Sema/CMakeLists.txt?rev=369591&r1=369590&r2=369591&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/unittests/Sema/CMakeLists.txt (original)
>>>> +++ cfe/trunk/unittests/Sema/CMakeLists.txt Wed Aug 21 15:08:59 2019
>>>> @@ -5,11 +5,13 @@ set(LLVM_LINK_COMPONENTS
>>>> add_clang_unittest(SemaTests
>>>> ExternalSemaSourceTest.cpp
>>>> CodeCompleteTest.cpp
>>>> + GslOwnerPointerInference.cpp
>>>> )
>>>>
>>>> clang_target_link_libraries(SemaTests
>>>> PRIVATE
>>>> clangAST
>>>> + clangASTMatchers
>>>> clangBasic
>>>> clangFrontend
>>>> clangParse
>>>>
>>>> Added: cfe/trunk/unittests/Sema/GslOwnerPointerInference.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Sema/GslOwnerPointerInference.cpp?rev=369591&view=auto
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/unittests/Sema/GslOwnerPointerInference.cpp (added)
>>>> +++ cfe/trunk/unittests/Sema/GslOwnerPointerInference.cpp Wed Aug 21
>>>> 15:08:59 2019
>>>> @@ -0,0 +1,61 @@
>>>> +//== unittests/Sema/GslOwnerPointerInference.cpp - gsl::Owner/Pointer
>>>> ========//
>>>> +//
>>>> +// Part of the LLVM Project, under the Apache License v2.0 with LLVM
>>>> Exceptions.
>>>> +// See https://llvm.org/LICENSE.txt for license information.
>>>> +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
>>>> +//
>>>>
>>>> +//===----------------------------------------------------------------------===//
>>>> +
>>>> +#include "../ASTMatchers/ASTMatchersTest.h"
>>>> +#include "clang/ASTMatchers/ASTMatchers.h"
>>>> +#include "gtest/gtest.h"
>>>> +
>>>> +namespace clang {
>>>> +using namespace ast_matchers;
>>>> +
>>>> +TEST(OwnerPointer, BothHaveAttributes) {
>>>> + EXPECT_TRUE(matches(
>>>> + R"cpp(
>>>> + template<class T>
>>>> + class [[gsl::Owner]] C;
>>>> +
>>>> + template<class T>
>>>> + class [[gsl::Owner]] C {};
>>>> +
>>>> + C<int> c;
>>>> + )cpp",
>>>> + classTemplateSpecializationDecl(hasName("C"),
>>>> hasAttr(clang::attr::Owner))));
>>>> +}
>>>> +
>>>> +TEST(OwnerPointer, ForwardDeclOnly) {
>>>> + EXPECT_TRUE(matches(
>>>> + R"cpp(
>>>> + template<class T>
>>>> + class [[gsl::Owner]] C;
>>>> +
>>>> + template<class T>
>>>> + class C {};
>>>> +
>>>> + C<int> c;
>>>> + )cpp",
>>>> + classTemplateSpecializationDecl(hasName("C"),
>>>> hasAttr(clang::attr::Owner))));
>>>> +}
>>>> +
>>>> +TEST(OwnerPointer, LateForwardDeclOnly) {
>>>> + EXPECT_TRUE(matches(
>>>> + R"cpp(
>>>> + template<class T>
>>>> + class C;
>>>> +
>>>> + template<class T>
>>>> + class C {};
>>>> +
>>>> + template<class T>
>>>> + class [[gsl::Owner]] C;
>>>> +
>>>> + C<int> c;
>>>> + )cpp",
>>>> + classTemplateSpecializationDecl(hasName("C"),
>>>> hasAttr(clang::attr::Owner))));
>>>> +}
>>>> +
>>>> +} // namespace clang
>>>>
>>>>
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