It looks like this fixes PR14564. Does it also fix the case in PR14564 comment#1?
On Mon, Jul 15, 2013 at 5:21 PM, Eli Friedman <[email protected]>wrote: > Author: efriedma > Date: Mon Jul 15 19:21:28 2013 > New Revision: 186370 > > URL: http://llvm.org/viewvc/llvm-project?rev=186370&view=rev > Log: > Fix alignment of class derived from empty class. > > The record layout code didn't properly take into account that > an empty class at offset 0 can have an alignment greater than 1. > > Patch by Andrea Di Biagio. > > Added: > cfe/trunk/test/SemaCXX/alignment-of-derived-class.cpp > Modified: > cfe/trunk/lib/AST/RecordLayoutBuilder.cpp > > Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=186370&r1=186369&r2=186370&view=diff > > ============================================================================== > --- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original) > +++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Mon Jul 15 19:21:28 2013 > @@ -1532,18 +1532,19 @@ CharUnits RecordLayoutBuilder::LayoutBas > } > } > > + CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlign(); > + CharUnits BaseAlign = (Packed) ? CharUnits::One() : UnpackedBaseAlign; > + > // If we have an empty base class, try to place it at offset 0. > if (Base->Class->isEmpty() && > (!HasExternalLayout || Offset == CharUnits::Zero()) && > EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) { > setSize(std::max(getSize(), Layout.getSize())); > + UpdateAlignment(BaseAlign, UnpackedBaseAlign); > > return CharUnits::Zero(); > } > > - CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlign(); > - CharUnits BaseAlign = (Packed) ? CharUnits::One() : UnpackedBaseAlign; > - > // The maximum field alignment overrides base align. > if (!MaxFieldAlignment.isZero()) { > BaseAlign = std::min(BaseAlign, MaxFieldAlignment); > > Added: cfe/trunk/test/SemaCXX/alignment-of-derived-class.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/alignment-of-derived-class.cpp?rev=186370&view=auto > > ============================================================================== > --- cfe/trunk/test/SemaCXX/alignment-of-derived-class.cpp (added) > +++ cfe/trunk/test/SemaCXX/alignment-of-derived-class.cpp Mon Jul 15 > 19:21:28 2013 > @@ -0,0 +1,41 @@ > +// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 > +// expected-no-diagnostics > + > +// Test that the alignment of a empty direct base class is correctly > +// inherited by the derived class. > + > +struct A { > +} __attribute__ ((aligned(16))); > + > +static_assert(__alignof(A) == 16, "A should be aligned to 16 bytes"); > + > +struct B1 : public A { > +}; > + > +static_assert(__alignof(B1) == 16, "B1 should be aligned to 16 bytes"); > + > +struct B2 : public A { > +} __attribute__ ((aligned(2))); > + > +static_assert(__alignof(B2) == 16, "B2 should be aligned to 16 bytes"); > + > +struct B3 : public A { > +} __attribute__ ((aligned(4))); > + > +static_assert(__alignof(B3) == 16, "B3 should be aligned to 16 bytes"); > + > +struct B4 : public A { > +} __attribute__ ((aligned(8))); > + > +static_assert(__alignof(B4) == 16, "B4 should be aligned to 16 bytes"); > + > +struct B5 : public A { > +} __attribute__ ((aligned(16))); > + > +static_assert(__alignof(B5) == 16, "B5 should be aligned to 16 bytes"); > + > +struct B6 : public A { > +} __attribute__ ((aligned(32))); > + > +static_assert(__alignof(B6) == 32, "B6 should be aligned to 32 bytes"); > + > > > _______________________________________________ > cfe-commits mailing list > [email protected] > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits >
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