r329342 - PR36992: do not store beyond the dsize of a class object unless we know
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Fri Apr 6 12:37:33 PDT 2018
Thanks, I see the problem.
On Fri, 6 Apr 2018, 11:56 via cfe-commits, <cfe-commits at lists.llvm.org>
wrote:
> Hi Richard,
>
> I don't know if you are aware, but the test you added in this commit,
> tail-padding.cpp is currently failing on one of the ARM bots. Can you take
> a look?
>
>
> http://lab.llvm.org:8011/builders/clang-cmake-armv7-selfhost-neon/builds/178
>
> ******************** TEST 'Clang :: CodeGenCXX/tail-padding.cpp' FAILED
> ********************
> Script:
> --
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/stage2/bin/clang
> -cc1 -internal-isystem
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/stage2/lib/clang/7.0.0/include
> -nostdsysteminc -triple armv7l-unknown-linux-gnueabihf -emit-llvm -o -
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/llvm/tools/clang/test/CodeGenCXX/tail-padding.cpp
> |
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/stage2/bin/FileCheck
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/llvm/tools/clang/test/CodeGenCXX/tail-padding.cpp
> --
> Exit Code: 1
>
> Command Output (stderr):
> --
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/llvm/tools/clang/test/CodeGenCXX/tail-padding.cpp:8:47:
> warning: static_assert with no message is a C++17 extension
> static_assert(sizeof(C) == sizeof(void*) + 8);
> ^
> , ""
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/llvm/tools/clang/test/CodeGenCXX/tail-padding.cpp:25:46:
> warning: static_assert with no message is a C++17 extension
> static_assert(sizeof(C) > sizeof(void*) + 8);
> ^
> , ""
> 2 warnings generated.
> /home/buildslave/buildslave/clang-cmake-armv7-selfhost-neon/llvm/tools/clang/test/CodeGenCXX/tail-padding.cpp:12:12:
> error: expected string not found in input
> // CHECK: call void @_ZN8Implicit1AC2ERKS0_(
> ^
> <stdin>:78:66: note: scanning from here
> define linkonce_odr %"struct.Implicit::C"*
> @_ZN8Implicit1CC1EOS0_(%"struct.Implicit::C"* returned %this,
> %"struct.Implicit::C"* dereferenceable(12)) unnamed_addr #0 comdat align 2 {
> ^
> <stdin>:97:28: note: possible intended match here
> %call = call %"struct.Implicit::A"*
> @_ZN8Implicit1AC2ERKS0_(%"struct.Implicit::A"* %3, %"struct.Implicit::A"*
> dereferenceable(1) %8)
> ^
>
> --
>
> ********************
>
> Douglas Yung
>
> > -----Original Message-----
> > From: cfe-commits [mailto:cfe-commits-bounces at lists.llvm.org] On Behalf
> Of
> > Richard Smith via cfe-commits
> > Sent: Thursday, April 05, 2018 13:53
> > To: cfe-commits at lists.llvm.org
> > Subject: r329342 - PR36992: do not store beyond the dsize of a class
> object
> > unless we know
> >
> > Author: rsmith
> > Date: Thu Apr 5 13:52:58 2018
> > New Revision: 329342
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=329342&view=rev
> > Log:
> > PR36992: do not store beyond the dsize of a class object unless we know
> the
> > tail padding is not reused.
> >
> > We track on the AggValueSlot (and through a couple of other
> initialization
> > actions) whether we're dealing with an object that might share its tail
> > padding with some other object, so that we can avoid emitting stores
> into the
> > tail padding if that's the case. We still widen stores into tail padding
> when
> > we can do so.
> >
> > Differential Revision: https://reviews.llvm.org/D45306
> >
> > Added:
> > cfe/trunk/test/CodeGenCXX/tail-padding.cpp
> > Modified:
> > cfe/trunk/lib/CodeGen/CGAtomic.cpp
> > cfe/trunk/lib/CodeGen/CGBlocks.cpp
> > cfe/trunk/lib/CodeGen/CGCall.cpp
> > cfe/trunk/lib/CodeGen/CGClass.cpp
> > cfe/trunk/lib/CodeGen/CGDecl.cpp
> > cfe/trunk/lib/CodeGen/CGDeclCXX.cpp
> > cfe/trunk/lib/CodeGen/CGExpr.cpp
> > cfe/trunk/lib/CodeGen/CGExprAgg.cpp
> > cfe/trunk/lib/CodeGen/CGExprCXX.cpp
> > cfe/trunk/lib/CodeGen/CGObjC.cpp
> > cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp
> > cfe/trunk/lib/CodeGen/CGStmt.cpp
> > cfe/trunk/lib/CodeGen/CGValue.h
> > cfe/trunk/lib/CodeGen/CodeGenFunction.h
> > cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
> >
> > Modified: cfe/trunk/lib/CodeGen/CGAtomic.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGAtomic.cpp?rev=329342&r1=329341&r2=329342&view
> > =diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGAtomic.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGAtomic.cpp Thu Apr 5 13:52:58 2018
> > @@ -1513,7 +1513,8 @@ void AtomicInfo::emitCopyIntoMemory(RVal
> > getAtomicType());
> > bool IsVolatile = rvalue.isVolatileQualified() ||
> > LVal.isVolatileQualified();
> > - CGF.EmitAggregateCopy(Dest, Src, getAtomicType(), IsVolatile);
> > + CGF.EmitAggregateCopy(Dest, Src, getAtomicType(),
> > + AggValueSlot::DoesNotOverlap, IsVolatile);
> > return;
> > }
> >
> > @@ -2008,6 +2009,7 @@ void CodeGenFunction::EmitAtomicInit(Exp
> > AggValueSlot::IsNotDestructed,
> >
> AggValueSlot::DoesNotNeedGCBarriers,
> > AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap,
> > Zeroed ? AggValueSlot::IsZeroed
> :
> >
> AggValueSlot::IsNotZeroed);
> >
> >
> > Modified: cfe/trunk/lib/CodeGen/CGBlocks.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGBlocks.cpp?rev=329342&r1=329341&r2=329342&view
> > =diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGBlocks.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGBlocks.cpp Thu Apr 5 13:52:58 2018
> > @@ -929,7 +929,8 @@ llvm::Value *CodeGenFunction::EmitBlockL
> > AggValueSlot::forAddr(blockField, Qualifiers(),
> > AggValueSlot::IsDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap);
> > EmitAggExpr(copyExpr, Slot);
> > } else {
> > EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr);
> >
> > Modified: cfe/trunk/lib/CodeGen/CGCall.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGCall.cpp?rev=329342&r1=329341&r2=329342&view=d
> > iff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGCall.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGCall.cpp Thu Apr 5 13:52:58 2018
> > @@ -3018,7 +3018,8 @@ static AggValueSlot createPlaceholderSlo
> > Ty.getQualifiers(),
> > AggValueSlot::IsNotDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap);
> > }
> >
> > void CodeGenFunction::EmitDelegateCallArg(CallArgList &args, @@ -3486,7
> > +3487,8 @@ RValue CallArg::getRValue(CodeGenFunctio
> > if (!HasLV)
> > return RV;
> > LValue Copy = CGF.MakeAddrLValue(CGF.CreateMemTemp(Ty), Ty);
> > - CGF.EmitAggregateCopy(Copy, LV, Ty, LV.isVolatile());
> > + CGF.EmitAggregateCopy(Copy, LV, Ty, AggValueSlot::DoesNotOverlap,
> > + LV.isVolatile());
> > IsUsed = true;
> > return RValue::getAggregate(Copy.getAddress());
> > }
> > @@ -3500,7 +3502,8 @@ void CallArg::copyInto(CodeGenFunction &
> > else {
> > auto Addr = HasLV ? LV.getAddress() : RV.getAggregateAddress();
> > LValue SrcLV = CGF.MakeAddrLValue(Addr, Ty);
> > - CGF.EmitAggregateCopy(Dst, SrcLV, Ty,
> > + // We assume that call args are never copied into subobjects.
> > + CGF.EmitAggregateCopy(Dst, SrcLV, Ty, AggValueSlot::DoesNotOverlap,
> > HasLV ? LV.isVolatileQualified()
> > : RV.isVolatileQualified());
> > }
> >
> > Modified: cfe/trunk/lib/CodeGen/CGClass.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGClass.cpp?rev=329342&r1=329341&r2=329342&view=
> > diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGClass.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGClass.cpp Thu Apr 5 13:52:58 2018
> > @@ -555,10 +555,12 @@ static void EmitBaseInitializer(CodeGenF
> > BaseClassDecl,
> > isBaseVirtual);
> > AggValueSlot AggSlot =
> > - AggValueSlot::forAddr(V, Qualifiers(),
> > - AggValueSlot::IsDestructed,
> > - AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::forAddr(
> > + V, Qualifiers(),
> > + AggValueSlot::IsDestructed,
> > + AggValueSlot::DoesNotNeedGCBarriers,
> > + AggValueSlot::IsNotAliased,
> > + CGF.overlapForBaseInit(ClassDecl, BaseClassDecl,
> > + isBaseVirtual));
> >
> > CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
> >
> > @@ -647,7 +649,8 @@ static void EmitMemberInitializer(CodeGe
> > LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV,
> Field);
> >
> > // Copy the aggregate.
> > - CGF.EmitAggregateCopy(LHS, Src, FieldType,
> LHS.isVolatileQualified());
> > + CGF.EmitAggregateCopy(LHS, Src, FieldType,
> > CGF.overlapForFieldInit(Field),
> > + LHS.isVolatileQualified());
> > // Ensure that we destroy the objects if an exception is thrown
> later
> > in
> > // the constructor.
> > QualType::DestructionKind dtorKind =
> FieldType.isDestructedType(); @@ -
> > 677,10 +680,12 @@ void CodeGenFunction::EmitInitializerFor
> > break;
> > case TEK_Aggregate: {
> > AggValueSlot Slot =
> > - AggValueSlot::forLValue(LHS,
> > - AggValueSlot::IsDestructed,
> > - AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::forLValue(
> > + LHS,
> > + AggValueSlot::IsDestructed,
> > + AggValueSlot::DoesNotNeedGCBarriers,
> > + AggValueSlot::IsNotAliased,
> > + overlapForFieldInit(Field));
> > EmitAggExpr(Init, Slot);
> > break;
> > }
> > @@ -911,15 +916,15 @@ namespace {
> > }
> >
> > CharUnits getMemcpySize(uint64_t FirstByteOffset) const {
> > + ASTContext &Ctx = CGF.getContext();
> > unsigned LastFieldSize =
> > - LastField->isBitField() ?
> > - LastField->getBitWidthValue(CGF.getContext()) :
> > - CGF.getContext().getTypeSize(LastField->getType());
> > - uint64_t MemcpySizeBits =
> > - LastFieldOffset + LastFieldSize - FirstByteOffset +
> > - CGF.getContext().getCharWidth() - 1;
> > - CharUnits MemcpySize =
> > - CGF.getContext().toCharUnitsFromBits(MemcpySizeBits);
> > + LastField->isBitField()
> > + ? LastField->getBitWidthValue(Ctx)
> > + : Ctx.toBits(
> > + Ctx.getTypeInfoDataSizeInChars(LastField-
> > >getType()).first);
> > + uint64_t MemcpySizeBits = LastFieldOffset + LastFieldSize -
> > + FirstByteOffset + Ctx.getCharWidth() -
> 1;
> > + CharUnits MemcpySize = Ctx.toCharUnitsFromBits(MemcpySizeBits);
> > return MemcpySize;
> > }
> >
> > @@ -1960,7 +1965,8 @@ void CodeGenFunction::EmitCXXAggrConstru
> > }
> >
> > EmitCXXConstructorCall(ctor, Ctor_Complete,
> /*ForVirtualBase=*/false,
> > - /*Delegating=*/false, curAddr, E);
> > + /*Delegating=*/false, curAddr, E,
> > + AggValueSlot::DoesNotOverlap);
> > }
> >
> > // Go to the next element.
> > @@ -1995,7 +2001,8 @@ void CodeGenFunction::EmitCXXConstructor
> > CXXCtorType Type,
> > bool ForVirtualBase,
> > bool Delegating, Address
> This,
> > - const CXXConstructExpr *E)
> {
> > + const CXXConstructExpr *E,
> > + AggValueSlot::Overlap_t
> > + Overlap) {
> > CallArgList Args;
> >
> > // Push the this ptr.
> > @@ -2011,7 +2018,7 @@ void CodeGenFunction::EmitCXXConstructor
> > LValue Src = EmitLValue(Arg);
> > QualType DestTy = getContext().getTypeDeclType(D->getParent());
> > LValue Dest = MakeAddrLValue(This, DestTy);
> > - EmitAggregateCopyCtor(Dest, Src);
> > + EmitAggregateCopyCtor(Dest, Src, Overlap);
> > return;
> > }
> >
> > @@ -2023,7 +2030,8 @@ void CodeGenFunction::EmitCXXConstructor
> > EmitCallArgs(Args, FPT, E->arguments(), E->getConstructor(),
> > /*ParamsToSkip*/ 0, Order);
> >
> > - EmitCXXConstructorCall(D, Type, ForVirtualBase, Delegating, This,
> Args);
> > + EmitCXXConstructorCall(D, Type, ForVirtualBase, Delegating, This,
> Args,
> > + Overlap);
> > }
> >
> > static bool canEmitDelegateCallArgs(CodeGenFunction &CGF, @@ -2055,7
> +2063,8
> > @@ void CodeGenFunction::EmitCXXConstructor
> > bool ForVirtualBase,
> > bool Delegating,
> > Address This,
> > - CallArgList &Args) {
> > + CallArgList &Args,
> > + AggValueSlot::Overlap_t
> > + Overlap) {
> > const CXXRecordDecl *ClassDecl = D->getParent();
> >
> > // C++11 [class.mfct.non-static]p2:
> > @@ -2082,7 +2091,7 @@ void CodeGenFunction::EmitCXXConstructor
> > LValue SrcLVal = MakeAddrLValue(Src, SrcTy);
> > QualType DestTy = getContext().getTypeDeclType(ClassDecl);
> > LValue DestLVal = MakeAddrLValue(This, DestTy);
> > - EmitAggregateCopyCtor(DestLVal, SrcLVal);
> > + EmitAggregateCopyCtor(DestLVal, SrcLVal, Overlap);
> > return;
> > }
> >
> > @@ -2171,7 +2180,7 @@ void CodeGenFunction::EmitInheritedCXXCo
> > }
> >
> > EmitCXXConstructorCall(D, Ctor_Base, ForVirtualBase,
> /*Delegating*/false,
> > - This, Args);
> > + This, Args, AggValueSlot::MayOverlap);
> > }
> >
> > void CodeGenFunction::EmitInlinedInheritingCXXConstructorCall(
> > @@ -2267,7 +2276,8 @@ CodeGenFunction::EmitSynthesizedCXXCopyC
> > EmitCallArgs(Args, FPT, drop_begin(E->arguments(), 1),
> E->getConstructor(),
> > /*ParamsToSkip*/ 1);
> >
> > - EmitCXXConstructorCall(D, Ctor_Complete, false, false, This, Args);
> > + EmitCXXConstructorCall(D, Ctor_Complete, false, false, This, Args,
> > + AggValueSlot::MayOverlap);
> > }
> >
> > void
> > @@ -2302,7 +2312,8 @@ CodeGenFunction::EmitDelegateCXXConstruc
> > }
> >
> > EmitCXXConstructorCall(Ctor, CtorType, /*ForVirtualBase=*/false,
> > - /*Delegating=*/true, This, DelegateArgs);
> > + /*Delegating=*/true, This, DelegateArgs,
> > + AggValueSlot::MayOverlap);
> > }
> >
> > namespace {
> > @@ -2333,7 +2344,8 @@ CodeGenFunction::EmitDelegatingCXXConstr
> > AggValueSlot::forAddr(ThisPtr, Qualifiers(),
> > AggValueSlot::IsDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::MayOverlap);
> >
> > EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
> >
> >
> > Modified: cfe/trunk/lib/CodeGen/CGDecl.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGDecl.cpp?rev=329342&r1=329341&r2=329342&view=d
> > iff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGDecl.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGDecl.cpp Thu Apr 5 13:52:58 2018
> > @@ -1416,17 +1416,17 @@ void CodeGenFunction::EmitAutoVarInit(co
> > }
> > }
> >
> > -/// Emit an expression as an initializer for a variable at the given
> -///
> > location. The expression is not necessarily the normal -/// initializer
> for
> > the variable, and the address is not necessarily
> > +/// Emit an expression as an initializer for an object (variable,
> > +field, etc.) /// at the given location. The expression is not
> > +necessarily the normal /// initializer for the object, and the address
> > +is not necessarily
> > /// its normal location.
> > ///
> > /// \param init the initializing expression -/// \param var the
> variable to
> > act as if we're initializing
> > +/// \param D the object to act as if we're initializing
> > /// \param loc the address to initialize; its type is a pointer
> > -/// to the LLVM mapping of the variable's type
> > +/// to the LLVM mapping of the object's type
> > /// \param alignment the alignment of the address -/// \param
> capturedByInit
> > true if the variable is a __block variable
> > +/// \param capturedByInit true if \p D is a __block variable
> > /// whose address is potentially changed by the initializer
> > void CodeGenFunction::EmitExprAsInit(const Expr *init, const ValueDecl
> *D,
> > LValue lvalue, bool
> capturedByInit) { @@
> > -1454,11 +1454,17 @@ void CodeGenFunction::EmitExprAsInit(con
> > if (type->isAtomicType()) {
> > EmitAtomicInit(const_cast<Expr*>(init), lvalue);
> > } else {
> > + AggValueSlot::Overlap_t Overlap = AggValueSlot::MayOverlap;
> > + if (isa<VarDecl>(D))
> > + Overlap = AggValueSlot::DoesNotOverlap;
> > + else if (auto *FD = dyn_cast<FieldDecl>(D))
> > + Overlap = overlapForFieldInit(FD);
> > // TODO: how can we delay here if D is captured by its
> initializer?
> > EmitAggExpr(init, AggValueSlot::forLValue(lvalue,
> >
> AggValueSlot::IsDestructed,
> >
> AggValueSlot::DoesNotNeedGCBarriers,
> > -
> AggValueSlot::IsNotAliased));
> > +
> AggValueSlot::IsNotAliased,
> > + Overlap));
> > }
> > return;
> > }
> >
> > Modified: cfe/trunk/lib/CodeGen/CGDeclCXX.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGDeclCXX.cpp?rev=329342&r1=329341&r2=329342&vie
> > w=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGDeclCXX.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGDeclCXX.cpp Thu Apr 5 13:52:58 2018
> > @@ -53,7 +53,8 @@ static void EmitDeclInit(CodeGenFunction
> > case TEK_Aggregate:
> > CGF.EmitAggExpr(Init,
> > AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
> >
> > AggValueSlot::DoesNotNeedGCBarriers,
> > -
> > AggValueSlot::IsNotAliased));
> > +
> AggValueSlot::IsNotAliased,
> > +
> > + AggValueSlot::DoesNotOverlap));
> > return;
> > }
> > llvm_unreachable("bad evaluation kind");
> >
> > Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=329342&r1=329341&r2=329342&view=d
> > iff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGExpr.cpp Thu Apr 5 13:52:58 2018
> > @@ -214,7 +214,8 @@ void CodeGenFunction::EmitAnyExprToMem(c
> > EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals,
> >
> > AggValueSlot::IsDestructed_t(IsInit),
> >
> AggValueSlot::DoesNotNeedGCBarriers,
> > -
> > AggValueSlot::IsAliased_t(!IsInit)));
> > +
> AggValueSlot::IsAliased_t(!IsInit),
> > + AggValueSlot::MayOverlap));
> > return;
> > }
> >
> > @@ -432,7 +433,8 @@ EmitMaterializeTemporaryExpr(const Mater
> > E->getType().getQualifiers(),
> > AggValueSlot::IsDestructed,
> >
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased));
> > + AggValueSlot::IsNotAliased,
> > +
> > + AggValueSlot::DoesNotOverlap));
> > break;
> > }
> > }
> >
> > Modified: cfe/trunk/lib/CodeGen/CGExprAgg.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGExprAgg.cpp?rev=329342&r1=329341&r2=329342&vie
> > w=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGExprAgg.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGExprAgg.cpp Thu Apr 5 13:52:58 2018
> > @@ -337,7 +337,8 @@ void AggExprEmitter::EmitFinalDestCopy(Q
> >
> > AggValueSlot srcAgg =
> > AggValueSlot::forLValue(src, AggValueSlot::IsDestructed,
> > - needsGC(type), AggValueSlot::IsAliased);
> > + needsGC(type), AggValueSlot::IsAliased,
> > + AggValueSlot::MayOverlap);
> > EmitCopy(type, Dest, srcAgg);
> > }
> >
> > @@ -348,7 +349,7 @@ void AggExprEmitter::EmitFinalDestCopy(Q
> > void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest,
> > const AggValueSlot &src) {
> > if (dest.requiresGCollection()) {
> > - CharUnits sz = CGF.getContext().getTypeSizeInChars(type);
> > + CharUnits sz = dest.getPreferredSize(CGF.getContext(), type);
> > llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy,
> sz.getQuantity());
> > CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF,
> >
> dest.getAddress(), @@ -
> > 362,7 +363,7 @@ void AggExprEmitter::EmitCopy(QualType t
> > // the two sides.
> > LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type);
> > LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type);
> > - CGF.EmitAggregateCopy(DestLV, SrcLV, type,
> > + CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(),
> > dest.isVolatile() || src.isVolatile()); }
> >
> > @@ -759,6 +760,7 @@ void AggExprEmitter::VisitCastExpr(CastE
> >
> valueDest.isExternallyDestructed(),
> >
> valueDest.requiresGCollection(),
> >
> valueDest.isPotentiallyAliased(),
> > + AggValueSlot::DoesNotOverlap,
> > AggValueSlot::IsZeroed);
> > }
> >
> > @@ -986,7 +988,8 @@ void AggExprEmitter::VisitBinAssign(cons
> > EmitCopy(E->getLHS()->getType(),
> > AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
> > needsGC(E->getLHS()->getType()),
> > - AggValueSlot::IsAliased),
> > + AggValueSlot::IsAliased,
> > + AggValueSlot::MayOverlap),
> > Dest);
> > return;
> > }
> > @@ -1007,7 +1010,8 @@ void AggExprEmitter::VisitBinAssign(cons
> > AggValueSlot LHSSlot =
> > AggValueSlot::forLValue(LHS, AggValueSlot::IsDestructed,
> > needsGC(E->getLHS()->getType()),
> > - AggValueSlot::IsAliased);
> > + AggValueSlot::IsAliased,
> > + AggValueSlot::MayOverlap);
> > // A non-volatile aggregate destination might have volatile member.
> > if (!LHSSlot.isVolatile() &&
> > CGF.hasVolatileMember(E->getLHS()->getType()))
> > @@ -1185,6 +1189,7 @@ AggExprEmitter::EmitInitializationToLVal
> >
> AggValueSlot::IsDestructed,
> >
> AggValueSlot::DoesNotNeedGCBarriers,
> >
> AggValueSlot::IsNotAliased,
> > +
> > + AggValueSlot::MayOverlap,
> > Dest.isZeroed()));
> > return;
> > case TEK_Scalar:
> > @@ -1283,11 +1288,12 @@ void AggExprEmitter::VisitInitListExpr(I
> > Address V = CGF.GetAddressOfDirectBaseInCompleteClass(
> > Dest.getAddress(), CXXRD, BaseRD,
> > /*isBaseVirtual*/ false);
> > - AggValueSlot AggSlot =
> > - AggValueSlot::forAddr(V, Qualifiers(),
> > - AggValueSlot::IsDestructed,
> > - AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot AggSlot = AggValueSlot::forAddr(
> > + V, Qualifiers(),
> > + AggValueSlot::IsDestructed,
> > + AggValueSlot::DoesNotNeedGCBarriers,
> > + AggValueSlot::IsNotAliased,
> > + CGF.overlapForBaseInit(CXXRD, BaseRD, Base.isVirtual()));
> > CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot);
> >
> > if (QualType::DestructionKind dtorKind = @@ -1468,7 +1474,9 @@
> void
> > AggExprEmitter::VisitArrayInitLoopE
> > // If the subexpression is an ArrayInitLoopExpr, share its
> cleanup.
> > auto elementSlot = AggValueSlot::forLValue(
> > elementLV, AggValueSlot::IsDestructed,
> > - AggValueSlot::DoesNotNeedGCBarriers,
> AggValueSlot::IsNotAliased);
> > + AggValueSlot::DoesNotNeedGCBarriers,
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap);
> > AggExprEmitter(CGF, elementSlot, false)
> > .VisitArrayInitLoopExpr(InnerLoop, outerBegin);
> > } else
> > @@ -1584,7 +1592,7 @@ static void CheckAggExprForMemSetUse(Agg
> > }
> >
> > // If the type is 16-bytes or smaller, prefer individual stores over
> > memset.
> > - CharUnits Size = CGF.getContext().getTypeSizeInChars(E->getType());
> > + CharUnits Size = Slot.getPreferredSize(CGF.getContext(),
> > + E->getType());
> > if (Size <= CharUnits::fromQuantity(16))
> > return;
> >
> > @@ -1630,13 +1638,37 @@ LValue CodeGenFunction::EmitAggExprToLVa
> > LValue LV = MakeAddrLValue(Temp, E->getType());
> > EmitAggExpr(E, AggValueSlot::forLValue(LV,
> AggValueSlot::IsNotDestructed,
> >
> AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased));
> > + AggValueSlot::IsNotAliased,
> > +
> > + AggValueSlot::DoesNotOverlap));
> > return LV;
> > }
> >
> > -void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src,
> > - QualType Ty, bool isVolatile,
> > - bool isAssignment) {
> > +AggValueSlot::Overlap_t CodeGenFunction::overlapForBaseInit(
> > + const CXXRecordDecl *RD, const CXXRecordDecl *BaseRD, bool
> > +IsVirtual) {
> > + // Virtual bases are initialized first, in address order, so there's
> > +never
> > + // any overlap during their initialization.
> > + //
> > + // FIXME: Under P0840, this is no longer true: the tail padding of a
> > +vbase
> > + // of a field could be reused by a vbase of a containing class.
> > + if (IsVirtual)
> > + return AggValueSlot::DoesNotOverlap;
> > +
> > + // If the base class is laid out entirely within the nvsize of the
> > + derived // class, its tail padding cannot yet be initialized, so we
> > + can issue // stores at the full width of the base class.
> > + const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
> > + if (Layout.getBaseClassOffset(BaseRD) +
> > + getContext().getASTRecordLayout(BaseRD).getSize() <=
> > + Layout.getNonVirtualSize())
> > + return AggValueSlot::DoesNotOverlap;
> > +
> > + // The tail padding may contain values we need to preserve.
> > + return AggValueSlot::MayOverlap;
> > +}
> > +
> > +void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src,
> QualType Ty,
> > + AggValueSlot::Overlap_t
> MayOverlap,
> > + bool isVolatile) {
> > assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
> >
> > Address DestPtr = Dest.getAddress();
> > @@ -1669,12 +1701,11 @@ void CodeGenFunction::EmitAggregateCopy(
> > // implementation handles this case safely. If there is a libc that
> does
> > not
> > // safely handle this, we can add a target hook.
> >
> > - // Get data size info for this aggregate. If this is an assignment,
> > - // don't copy the tail padding, because we might be assigning into a
> > - // base subobject where the tail padding is claimed. Otherwise,
> > - // copying it is fine.
> > + // Get data size info for this aggregate. Don't copy the tail padding
> > + if this // might be a potentially-overlapping subobject, since the
> > + tail padding might // be occupied by a different object. Otherwise,
> copying
> > it is fine.
> > std::pair<CharUnits, CharUnits> TypeInfo;
> > - if (isAssignment)
> > + if (MayOverlap)
> > TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty);
> > else
> > TypeInfo = getContext().getTypeInfoInChars(Ty);
> > @@ -1686,22 +1717,11 @@ void CodeGenFunction::EmitAggregateCopy(
> > getContext().getAsArrayType(Ty))) {
> > QualType BaseEltTy;
> > SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr);
> > - TypeInfo = getContext().getTypeInfoDataSizeInChars(BaseEltTy);
> > - std::pair<CharUnits, CharUnits> LastElementTypeInfo;
> > - if (!isAssignment)
> > - LastElementTypeInfo =
> getContext().getTypeInfoInChars(BaseEltTy);
> > + TypeInfo = getContext().getTypeInfoInChars(BaseEltTy);
> > assert(!TypeInfo.first.isZero());
> > SizeVal = Builder.CreateNUWMul(
> > SizeVal,
> > llvm::ConstantInt::get(SizeTy, TypeInfo.first.getQuantity()));
> > - if (!isAssignment) {
> > - SizeVal = Builder.CreateNUWSub(
> > - SizeVal,
> > - llvm::ConstantInt::get(SizeTy,
> TypeInfo.first.getQuantity()));
> > - SizeVal = Builder.CreateNUWAdd(
> > - SizeVal, llvm::ConstantInt::get(
> > - SizeTy,
> LastElementTypeInfo.first.getQuantity()));
> > - }
> > }
> > }
> > if (!SizeVal) {
> >
> > Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=329342&r1=329341&r2=329342&vie
> > w=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Thu Apr 5 13:52:58 2018
> > @@ -279,7 +279,10 @@ RValue CodeGenFunction::EmitCXXMemberOrO
> > const Expr *Arg = *CE->arg_begin();
> > LValue RHS = EmitLValue(Arg);
> > LValue Dest = MakeAddrLValue(This.getAddress(), Arg->getType());
> > - EmitAggregateCopy(Dest, RHS, Arg->getType());
> > + // This is the MSVC p->Ctor::Ctor(...) extension. We assume
> that's
> > + // constructing a new complete object of type Ctor.
> > + EmitAggregateCopy(Dest, RHS, Arg->getType(),
> > + AggValueSlot::DoesNotOverlap);
> > return RValue::get(This.getPointer());
> > }
> > llvm_unreachable("unknown trivial member function"); @@ -631,7
> +634,7
> > @@ CodeGenFunction::EmitCXXConstructExpr(co
> >
> > // Call the constructor.
> > EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating,
> > - Dest.getAddress(), E);
> > + Dest.getAddress(), E, Dest.mayOverlap());
> > }
> > }
> >
> > @@ -933,7 +936,8 @@ static llvm::Value *EmitCXXNewAllocSize( }
> >
> > static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr
> *Init,
> > - QualType AllocType, Address NewPtr)
> {
> > + QualType AllocType, Address NewPtr,
> > + AggValueSlot::Overlap_t MayOverlap)
> > + {
> > // FIXME: Refactor with EmitExprAsInit.
> > switch (CGF.getEvaluationKind(AllocType)) {
> > case TEK_Scalar:
> > @@ -949,7 +953,8 @@ static void StoreAnyExprIntoOneUnit(Code
> > = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
> > AggValueSlot::IsDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::IsNotAliased,
> > + MayOverlap);
> > CGF.EmitAggExpr(Init, Slot);
> > return;
> > }
> > @@ -1018,7 +1023,8 @@ void CodeGenFunction::EmitNewArrayInitia
> > AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(),
> > AggValueSlot::IsDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap);
> > EmitAggExpr(ILE->getInit(0), Slot);
> >
> > // Move past these elements.
> > @@ -1083,7 +1089,8 @@ void CodeGenFunction::EmitNewArrayInitia
> > // an array, and we have an array filler, we can fold together
> the two
> > // initialization loops.
> > StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
> > - ILE->getInit(i)->getType(), CurPtr);
> > + ILE->getInit(i)->getType(), CurPtr,
> > + AggValueSlot::DoesNotOverlap);
> > CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
> > Builder.getSize(1),
> > "array.exp.next"), @@ -
> > 1236,7 +1243,8 @@ void CodeGenFunction::EmitNewArrayInitia
> > }
> >
> > // Emit the initializer into this element.
> > - StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr);
> > + StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr,
> > + AggValueSlot::DoesNotOverlap);
> >
> > // Leave the Cleanup if we entered one.
> > if (CleanupDominator) {
> > @@ -1267,7 +1275,8 @@ static void EmitNewInitializer(CodeGenFu
> > CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr,
> > NumElements,
> > AllocSizeWithoutCookie);
> > else if (const Expr *Init = E->getInitializer())
> > - StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr);
> > + StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr,
> > + AggValueSlot::DoesNotOverlap);
> > }
> >
> > /// Emit a call to an operator new or operator delete function, as
> implicitly
> >
> > Modified: cfe/trunk/lib/CodeGen/CGObjC.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGObjC.cpp?rev=329342&r1=329341&r2=329342&view=d
> > iff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGObjC.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGObjC.cpp Thu Apr 5 13:52:58 2018
> > @@ -1013,8 +1013,9 @@ CodeGenFunction::generateObjCGetterBody(
> > // that's not necessarily the same as "on the stack", so
> > // we still potentially need objc_memmove_collectable.
> > EmitAggregateCopy(/* Dest= */ MakeAddrLValue(ReturnValue,
> ivarType),
> > - /* Src= */ LV, ivarType);
> > - return; }
> > + /* Src= */ LV, ivarType,
> overlapForReturnValue());
> > + return;
> > + }
> > case TEK_Scalar: {
> > llvm::Value *value;
> > if (propType->isReferenceType()) { @@ -1439,7 +1440,8 @@ void
> > CodeGenFunction::GenerateObjCCtorDt
> > EmitAggExpr(IvarInit->getInit(),
> > AggValueSlot::forLValue(LV,
> AggValueSlot::IsDestructed,
> >
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased));
> > + AggValueSlot::IsNotAliased,
> > +
> > + AggValueSlot::DoesNotOverlap));
> > }
> > // constructor returns 'self'.
> > CodeGenTypes &Types = CGM.getTypes(); @@ -3381,7 +3383,8 @@
> > CodeGenFunction::GenerateObjCAtomicGette
> > Qualifiers(),
> > AggValueSlot::IsDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased));
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap));
> >
> > FinishFunction();
> > HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
> >
> > Modified: cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp?rev=329342&r1=329341&r2=3293
> > 42&view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGOpenMPRuntime.cpp Thu Apr 5 13:52:58 2018
> > @@ -4793,7 +4793,7 @@ CGOpenMPRuntime::emitTaskInit(CodeGenFun
> > CGF.getNaturalTypeAlignment(SharedsTy));
> > LValue Dest = CGF.MakeAddrLValue(KmpTaskSharedsPtr, SharedsTy);
> > LValue Src = CGF.MakeAddrLValue(Shareds, SharedsTy);
> > - CGF.EmitAggregateCopy(Dest, Src, SharedsTy);
> > + CGF.EmitAggregateCopy(Dest, Src, SharedsTy,
> > + AggValueSlot::DoesNotOverlap);
> > }
> > // Emit initial values for private copies (if any).
> > TaskResultTy Result;
> >
> > Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=329342&r1=329341&r2=329342&view=d
> > iff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGStmt.cpp Thu Apr 5 13:52:58 2018
> > @@ -1007,7 +1007,7 @@ void CodeGenFunction::EmitReturnOfRValue
> > } else if (RV.isAggregate()) {
> > LValue Dest = MakeAddrLValue(ReturnValue, Ty);
> > LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
> > - EmitAggregateCopy(Dest, Src, Ty);
> > + EmitAggregateCopy(Dest, Src, Ty, overlapForReturnValue());
> > } else {
> > EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue,
> Ty),
> > /*init*/ true);
> > @@ -1085,11 +1085,12 @@ void CodeGenFunction::EmitReturnStmt(con
> > /*isInit*/ true);
> > break;
> > case TEK_Aggregate:
> > - EmitAggExpr(RV, AggValueSlot::forAddr(ReturnValue,
> > - Qualifiers(),
> > - AggValueSlot::IsDestructed,
> > -
> > AggValueSlot::DoesNotNeedGCBarriers,
> > -
> AggValueSlot::IsNotAliased));
> > + EmitAggExpr(RV, AggValueSlot::forAddr(
> > + ReturnValue, Qualifiers(),
> > + AggValueSlot::IsDestructed,
> > + AggValueSlot::DoesNotNeedGCBarriers,
> > + AggValueSlot::IsNotAliased,
> > + overlapForReturnValue()));
> > break;
> > }
> > }
> >
> > Modified: cfe/trunk/lib/CodeGen/CGValue.h
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CGValue.h?rev=329342&r1=329341&r2=329342&view=di
> > ff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGValue.h (original)
> > +++ cfe/trunk/lib/CodeGen/CGValue.h Thu Apr 5 13:52:58 2018
> > @@ -472,17 +472,25 @@ class AggValueSlot {
> > /// evaluating an expression which constructs such an object.
> > bool AliasedFlag : 1;
> >
> > + /// This is set to true if the tail padding of this slot might
> > + overlap /// another object that may have already been initialized
> > + (and whose /// value must be preserved by this initialization). If
> > + so, we may only /// store up to the dsize of the type. Otherwise we
> > + can widen stores to /// the size of the type.
> > + bool OverlapFlag : 1;
> > +
> > public:
> > enum IsAliased_t { IsNotAliased, IsAliased };
> > enum IsDestructed_t { IsNotDestructed, IsDestructed };
> > enum IsZeroed_t { IsNotZeroed, IsZeroed };
> > + enum Overlap_t { DoesNotOverlap, MayOverlap };
> > enum NeedsGCBarriers_t { DoesNotNeedGCBarriers, NeedsGCBarriers };
> >
> > /// ignored - Returns an aggregate value slot indicating that the
> > /// aggregate value is being ignored.
> > static AggValueSlot ignored() {
> > return forAddr(Address::invalid(), Qualifiers(), IsNotDestructed,
> > - DoesNotNeedGCBarriers, IsNotAliased);
> > + DoesNotNeedGCBarriers, IsNotAliased,
> > + DoesNotOverlap);
> > }
> >
> > /// forAddr - Make a slot for an aggregate value.
> > @@ -500,6 +508,7 @@ public:
> > IsDestructed_t isDestructed,
> > NeedsGCBarriers_t needsGC,
> > IsAliased_t isAliased,
> > + Overlap_t mayOverlap,
> > IsZeroed_t isZeroed = IsNotZeroed) {
> > AggValueSlot AV;
> > if (addr.isValid()) {
> > @@ -514,6 +523,7 @@ public:
> > AV.ObjCGCFlag = needsGC;
> > AV.ZeroedFlag = isZeroed;
> > AV.AliasedFlag = isAliased;
> > + AV.OverlapFlag = mayOverlap;
> > return AV;
> > }
> >
> > @@ -521,9 +531,10 @@ public:
> > IsDestructed_t isDestructed,
> > NeedsGCBarriers_t needsGC,
> > IsAliased_t isAliased,
> > + Overlap_t mayOverlap,
> > IsZeroed_t isZeroed = IsNotZeroed) {
> > - return forAddr(LV.getAddress(),
> > - LV.getQuals(), isDestructed, needsGC, isAliased,
> > isZeroed);
> > + return forAddr(LV.getAddress(), LV.getQuals(), isDestructed,
> needsGC,
> > + isAliased, mayOverlap, isZeroed);
> > }
> >
> > IsDestructed_t isExternallyDestructed() const { @@ -571,6 +582,10 @@
> > public:
> > return IsAliased_t(AliasedFlag);
> > }
> >
> > + Overlap_t mayOverlap() const {
> > + return Overlap_t(OverlapFlag);
> > + }
> > +
> > RValue asRValue() const {
> > if (isIgnored()) {
> > return RValue::getIgnored();
> > @@ -583,6 +598,14 @@ public:
> > IsZeroed_t isZeroed() const {
> > return IsZeroed_t(ZeroedFlag);
> > }
> > +
> > + /// Get the preferred size to use when storing a value to this slot.
> > + This /// is the type size unless that might overlap another object,
> > + in which /// case it's the dsize.
> > + CharUnits getPreferredSize(ASTContext &Ctx, QualType Type) const {
> > + return mayOverlap() ? Ctx.getTypeInfoDataSizeInChars(Type).first
> > + : Ctx.getTypeSizeInChars(Type); }
> > };
> >
> > } // end namespace CodeGen
> >
> > Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=329342&r1=329341&r2=329342
> > &view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
> > +++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Thu Apr 5 13:52:58 2018
> > @@ -2061,7 +2061,8 @@ public:
> > T.getQualifiers(),
> > AggValueSlot::IsNotDestructed,
> > AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased);
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap);
> > }
> >
> > /// Emit a cast to void* in the appropriate address space.
> > @@ -2118,28 +2119,52 @@ public:
> > }
> > return false;
> > }
> > - /// EmitAggregateCopy - Emit an aggregate assignment.
> > - ///
> > - /// The difference to EmitAggregateCopy is that tail padding is not
> copied.
> > - /// This is required for correctness when assigning non-POD
> structures in
> > C++.
> > +
> > + /// Determine whether a return value slot may overlap some other
> object.
> > + AggValueSlot::Overlap_t overlapForReturnValue() {
> > + // FIXME: Assuming no overlap here breaks guaranteed copy elision
> for
> > base
> > + // class subobjects. These cases may need to be revisited depending
> on
> > the
> > + // resolution of the relevant core issue.
> > + return AggValueSlot::DoesNotOverlap; }
> > +
> > + /// Determine whether a field initialization may overlap some other
> object.
> > + AggValueSlot::Overlap_t overlapForFieldInit(const FieldDecl *FD) {
> > + // FIXME: These cases can result in overlap as a result of P0840R0's
> > + // [[no_unique_address]] attribute. We can still infer NoOverlap in
> the
> > + // presence of that attribute if the field is within the nvsize of
> its
> > + // containing class, because non-virtual subobjects are initialized
> in
> > + // address order.
> > + return AggValueSlot::DoesNotOverlap; }
> > +
> > + /// Determine whether a base class initialization may overlap some
> > + other /// object.
> > + AggValueSlot::Overlap_t overlapForBaseInit(const CXXRecordDecl *RD,
> > + const CXXRecordDecl
> *BaseRD,
> > + bool IsVirtual);
> > +
> > + /// Emit an aggregate assignment.
> > void EmitAggregateAssign(LValue Dest, LValue Src, QualType EltTy) {
> > bool IsVolatile = hasVolatileMember(EltTy);
> > - EmitAggregateCopy(Dest, Src, EltTy, IsVolatile, /* isAssignment= */
> > true);
> > + EmitAggregateCopy(Dest, Src, EltTy, AggValueSlot::MayOverlap,
> > + IsVolatile);
> > }
> >
> > - void EmitAggregateCopyCtor(LValue Dest, LValue Src) {
> > - EmitAggregateCopy(Dest, Src, Src.getType(),
> > - /* IsVolatile= */ false, /* IsAssignment= */
> false);
> > + void EmitAggregateCopyCtor(LValue Dest, LValue Src,
> > + AggValueSlot::Overlap_t MayOverlap) {
> > + EmitAggregateCopy(Dest, Src, Src.getType(), MayOverlap);
> > }
> >
> > /// EmitAggregateCopy - Emit an aggregate copy.
> > ///
> > - /// \param isVolatile - True iff either the source or the destination
> is
> > - /// volatile.
> > - /// \param isAssignment - If false, allow padding to be copied. This
> often
> > - /// yields more efficient.
> > + /// \param isVolatile \c true iff either the source or the
> destination is
> > + /// volatile.
> > + /// \param MayOverlap Whether the tail padding of the destination
> might be
> > + /// occupied by some other object. More efficient code can
> often be
> > + /// generated if not.
> > void EmitAggregateCopy(LValue Dest, LValue Src, QualType EltTy,
> > - bool isVolatile = false, bool isAssignment =
> false);
> > + AggValueSlot::Overlap_t MayOverlap,
> > + bool isVolatile = false);
> >
> > /// GetAddrOfLocalVar - Return the address of a local variable.
> > Address GetAddrOfLocalVar(const VarDecl *VD) { @@ -2303,11 +2328,13 @@
> > public:
> >
> > void EmitCXXConstructorCall(const CXXConstructorDecl *D, CXXCtorType
> Type,
> > bool ForVirtualBase, bool Delegating,
> > - Address This, const CXXConstructExpr *E);
> > + Address This, const CXXConstructExpr *E,
> > + AggValueSlot::Overlap_t Overlap);
> >
> > void EmitCXXConstructorCall(const CXXConstructorDecl *D, CXXCtorType
> Type,
> > bool ForVirtualBase, bool Delegating,
> > - Address This, CallArgList &Args);
> > + Address This, CallArgList &Args,
> > + AggValueSlot::Overlap_t Overlap);
> >
> > /// Emit assumption load for all bases. Requires to be be called only
> on
> > /// most-derived class and not under construction of the object.
> >
> > Modified: cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
> > URL: http://llvm.org/viewvc/llvm-
> >
> project/cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp?rev=329342&r1=329341&r2=329342
> > &view=diff
> >
> ==============================================================================
> > --- cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp Thu Apr 5 13:52:58 2018
> > @@ -3896,7 +3896,7 @@ static void InitCatchParam(CodeGenFuncti
> > caughtExnAlignment);
> > LValue Dest = CGF.MakeAddrLValue(ParamAddr, CatchType);
> > LValue Src = CGF.MakeAddrLValue(adjustedExn, CatchType);
> > - CGF.EmitAggregateCopy(Dest, Src, CatchType);
> > + CGF.EmitAggregateCopy(Dest, Src, CatchType,
> > + AggValueSlot::DoesNotOverlap);
> > return;
> > }
> >
> > @@ -3923,7 +3923,8 @@ static void InitCatchParam(CodeGenFuncti
> > AggValueSlot::forAddr(ParamAddr, Qualifiers(),
> > AggValueSlot::IsNotDestructed,
> >
> AggValueSlot::DoesNotNeedGCBarriers,
> > - AggValueSlot::IsNotAliased));
> > + AggValueSlot::IsNotAliased,
> > + AggValueSlot::DoesNotOverlap));
> >
> > // Leave the terminate scope.
> > CGF.EHStack.popTerminate();
> >
> > Added: cfe/trunk/test/CodeGenCXX/tail-padding.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/tail-
> > padding.cpp?rev=329342&view=auto
> >
> ==============================================================================
> > --- cfe/trunk/test/CodeGenCXX/tail-padding.cpp (added)
> > +++ cfe/trunk/test/CodeGenCXX/tail-padding.cpp Thu Apr 5 13:52:58 2018
> > @@ -0,0 +1,34 @@
> > +// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm -o - %s |
> > +FileCheck %s
> > +
> > +// PR36992
> > +namespace Implicit {
> > + struct A { char c; A(const A&); };
> > + struct B { int n; char c[3]; ~B(); };
> > + struct C : B, virtual A {};
> > + static_assert(sizeof(C) == sizeof(void*) + 8);
> > + C f(C c) { return c; }
> > +
> > + // CHECK: define {{.*}} @_ZN8Implicit1CC1EOS0_
> > + // CHECK: call void @_ZN8Implicit1AC2ERKS0_(
> > + // Note: this must memcpy 7 bytes, not 8, to avoid trampling over the
> > virtual base class.
> > + // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* {{.*}}, i8*
> > +{{.*}}, i64 7, i1 false)
> > + // CHECK: store i32 {{.*}} @_ZTVN8Implicit1CE }
> > +
> > +namespace InitWithinNVSize {
> > + // This is the same as the previous test, except that the A base lies
> > + // entirely within the nvsize of C. This makes it valid to copy at
> > +the
> > + // full width.
> > + struct A { char c; A(const A&); };
> > + struct B { int n; char c[3]; ~B(); };
> > + struct C : B, virtual A { char x; };
> > + static_assert(sizeof(C) > sizeof(void*) + 8);
> > + C f(C c) { return c; }
> > +
> > + // CHECK: define {{.*}} @_ZN16InitWithinNVSize1CC1EOS0_
> > + // CHECK: call void @_ZN16InitWithinNVSize1AC2ERKS0_(
> > + // This copies over the 'C::x' member, but that's OK because we've not
> > initialized it yet.
> > + // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* {{.*}}, i8*
> > +{{.*}}, i64 8, i1 false)
> > + // CHECK: store i32 {{.*}} @_ZTVN16InitWithinNVSize1CE
> > + // CHECK: store i8
> > +}
> >
> >
> > _______________________________________________
> > cfe-commits mailing list
> > cfe-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
> _______________________________________________
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