r350917 - [Sema] If CheckPlaceholderExpr rewrites the initializer of an auto
Akira Hatanaka via cfe-commits
cfe-commits at lists.llvm.org
Wed May 29 21:59:32 PDT 2019
Hi Richard,
Thank you for the feedback. Please review my new patch: https://reviews.llvm.org/D62645 <https://reviews.llvm.org/D62645>.
> On Apr 23, 2019, at 7:21 PM, Richard Smith <richard at metafoo.co.uk> wrote:
>
> Hi Akira,
>
> I've reverted this in r359066. This subtly breaks the semantics of C++
> initializers by strripping off an outer level of parentheses / braces
> in some cases. Testcase:
>
> struct A {
> A();
> A(const A&) = delete;
> };
> auto x = [a{A()}] {};
>
> (This should be accepted in C++17 mode onwards, but this patch rejects
> it by losing the braces around the A() expression.)
>
> Moreover, I think this is fundamentally the wrong approach:
> DeduceAutoType should not ever be changing the initializer expression
> (and it certainly shouldn't expect those changes to stick around).
> Instead, we should check for a placeholder type before attempting
> deduction, just like we correct typos in the initializer before
> attempting deduction.
>
> On Thu, 10 Jan 2019 at 21:01, Akira Hatanaka via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
>>
>> Author: ahatanak
>> Date: Thu Jan 10 20:57:34 2019
>> New Revision: 350917
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=350917&view=rev
>> Log:
>> [Sema] If CheckPlaceholderExpr rewrites the initializer of an auto
>> variable during auto type deduction, use the rewritten initializer when
>> performing initialization of the variable.
>>
>> This silences spurious -Warc-repeated-use-of-weak warnings that are
>> issued when the initializer uses a weak ObjC pointer.
>>
>> Differential Revision: https://reviews.llvm.org/D55662
>>
>> Modified:
>> cfe/trunk/include/clang/Sema/Sema.h
>> cfe/trunk/lib/Sema/SemaDecl.cpp
>> cfe/trunk/lib/Sema/SemaExprCXX.cpp
>> cfe/trunk/lib/Sema/SemaLambda.cpp
>> cfe/trunk/test/SemaObjC/arc-repeated-weak.mm
>>
>> Modified: cfe/trunk/include/clang/Sema/Sema.h
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=350917&r1=350916&r2=350917&view=diff
>> ==============================================================================
>> --- cfe/trunk/include/clang/Sema/Sema.h (original)
>> +++ cfe/trunk/include/clang/Sema/Sema.h Thu Jan 10 20:57:34 2019
>> @@ -1960,7 +1960,7 @@ public:
>> bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
>> void CheckVariableDeclarationType(VarDecl *NewVD);
>> bool DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
>> - Expr *Init);
>> + Expr *&Init);
>> void CheckCompleteVariableDeclaration(VarDecl *VD);
>> void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
>> void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);
>> @@ -7095,7 +7095,7 @@ public:
>> QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
>> QualType Type, TypeSourceInfo *TSI,
>> SourceRange Range, bool DirectInit,
>> - Expr *Init);
>> + Expr *&Init);
>>
>> TypeLoc getReturnTypeLoc(FunctionDecl *FD) const;
>>
>>
>> Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=350917&r1=350916&r2=350917&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaDecl.cpp Thu Jan 10 20:57:34 2019
>> @@ -10812,7 +10812,7 @@ QualType Sema::deduceVarTypeFromInitiali
>> DeclarationName Name, QualType Type,
>> TypeSourceInfo *TSI,
>> SourceRange Range, bool DirectInit,
>> - Expr *Init) {
>> + Expr *&Init) {
>> bool IsInitCapture = !VDecl;
>> assert((!VDecl || !VDecl->isInitCapture()) &&
>> "init captures are expected to be deduced prior to initialization");
>> @@ -10928,7 +10928,8 @@ QualType Sema::deduceVarTypeFromInitiali
>> << (DeduceInit->getType().isNull() ? TSI->getType()
>> : DeduceInit->getType())
>> << DeduceInit->getSourceRange();
>> - }
>> + } else
>> + Init = DeduceInit;
>>
>> // Warn if we deduced 'id'. 'auto' usually implies type-safety, but using
>> // 'id' instead of a specific object type prevents most of our usual
>> @@ -10945,7 +10946,7 @@ QualType Sema::deduceVarTypeFromInitiali
>> }
>>
>> bool Sema::DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
>> - Expr *Init) {
>> + Expr *&Init) {
>> QualType DeducedType = deduceVarTypeFromInitializer(
>> VDecl, VDecl->getDeclName(), VDecl->getType(), VDecl->getTypeSourceInfo(),
>> VDecl->getSourceRange(), DirectInit, Init);
>> @@ -11451,8 +11452,9 @@ void Sema::ActOnUninitializedDecl(Decl *
>> return;
>> }
>>
>> + Expr *TmpInit = nullptr;
>> if (Type->isUndeducedType() &&
>> - DeduceVariableDeclarationType(Var, false, nullptr))
>> + DeduceVariableDeclarationType(Var, false, TmpInit))
>> return;
>>
>> // C++11 [class.static.data]p3: A static data member can be declared with
>>
>> Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=350917&r1=350916&r2=350917&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Thu Jan 10 20:57:34 2019
>> @@ -1865,12 +1865,11 @@ Sema::BuildCXXNew(SourceRange Range, boo
>> if (Braced && !getLangOpts().CPlusPlus17)
>> Diag(Initializer->getBeginLoc(), diag::ext_auto_new_list_init)
>> << AllocType << TypeRange;
>> - Expr *Deduce = Inits[0];
>> QualType DeducedType;
>> - if (DeduceAutoType(AllocTypeInfo, Deduce, DeducedType) == DAR_Failed)
>> + if (DeduceAutoType(AllocTypeInfo, Inits[0], DeducedType) == DAR_Failed)
>> return ExprError(Diag(StartLoc, diag::err_auto_new_deduction_failure)
>> - << AllocType << Deduce->getType()
>> - << TypeRange << Deduce->getSourceRange());
>> + << AllocType << Inits[0]->getType()
>> + << TypeRange << Inits[0]->getSourceRange());
>> if (DeducedType.isNull())
>> return ExprError();
>> AllocType = DeducedType;
>>
>> Modified: cfe/trunk/lib/Sema/SemaLambda.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLambda.cpp?rev=350917&r1=350916&r2=350917&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaLambda.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaLambda.cpp Thu Jan 10 20:57:34 2019
>> @@ -759,14 +759,15 @@ QualType Sema::buildLambdaInitCaptureIni
>> TypeSourceInfo *TSI = TLB.getTypeSourceInfo(Context, DeductType);
>>
>> // Deduce the type of the init capture.
>> + Expr *DeduceInit = Init;
>> QualType DeducedType = deduceVarTypeFromInitializer(
>> /*VarDecl*/nullptr, DeclarationName(Id), DeductType, TSI,
>> - SourceRange(Loc, Loc), IsDirectInit, Init);
>> + SourceRange(Loc, Loc), IsDirectInit, DeduceInit);
>> if (DeducedType.isNull())
>> return QualType();
>>
>> // Are we a non-list direct initialization?
>> - ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init);
>> + bool CXXDirectInit = isa<ParenListExpr>(Init);
>>
>> // Perform initialization analysis and ensure any implicit conversions
>> // (such as lvalue-to-rvalue) are enforced.
>> @@ -779,10 +780,7 @@ QualType Sema::buildLambdaInitCaptureIni
>> : InitializationKind::CreateDirectList(Loc))
>> : InitializationKind::CreateCopy(Loc, Init->getBeginLoc());
>>
>> - MultiExprArg Args = Init;
>> - if (CXXDirectInit)
>> - Args =
>> - MultiExprArg(CXXDirectInit->getExprs(), CXXDirectInit->getNumExprs());
>> + MultiExprArg Args = DeduceInit;
>> QualType DclT;
>> InitializationSequence InitSeq(*this, Entity, Kind, Args);
>> ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT);
>>
>> Modified: cfe/trunk/test/SemaObjC/arc-repeated-weak.mm
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/arc-repeated-weak.mm?rev=350917&r1=350916&r2=350917&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/SemaObjC/arc-repeated-weak.mm (original)
>> +++ cfe/trunk/test/SemaObjC/arc-repeated-weak.mm Thu Jan 10 20:57:34 2019
>> @@ -1,5 +1,5 @@
>> -// RUN: %clang_cc1 -fsyntax-only -fobjc-runtime-has-weak -fobjc-arc -fblocks -Wno-objc-root-class -std=c++11 -Warc-repeated-use-of-weak -verify %s
>> -// RUN: %clang_cc1 -fsyntax-only -fobjc-runtime-has-weak -fobjc-weak -fblocks -Wno-objc-root-class -std=c++11 -Warc-repeated-use-of-weak -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -fobjc-runtime-has-weak -fobjc-arc -fblocks -Wno-objc-root-class -std=c++14 -Warc-repeated-use-of-weak -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -fobjc-runtime-has-weak -fobjc-weak -fblocks -Wno-objc-root-class -std=c++14 -Warc-repeated-use-of-weak -verify %s
>>
>> @interface Test {
>> @public
>> @@ -467,6 +467,18 @@ void foo() {
>> __typeof__(NSBundle2.foo2.weakProp) t5;
>> }
>>
>> +void testAuto() {
>> + auto __weak wp = NSBundle2.foo2.weakProp;
>> +}
>> +
>> +void testLambdaCaptureInit() {
>> + [capture(NSBundle2.foo2.weakProp)] {} ();
>> +}
>> +
>> +void testAutoNew() {
>> + auto p = new auto(NSBundle2.foo2.weakProp);
>> +}
>> +
>> // This used to crash in the constructor of WeakObjectProfileTy when a
>> // DeclRefExpr was passed that didn't reference a VarDecl.
>>
>>
>>
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>> cfe-commits at lists.llvm.org
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