From: Momchil Velikov Date: Mon, 21 May 2018 14:28:43 +0000 (+0000) Subject: [Sema] Fix incorrect packed aligned structure layout X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dc6b868ff22d0bf6d426d177578a8afd9231bdea;p=clang [Sema] Fix incorrect packed aligned structure layout Handle attributes before checking the record layout (e.g. underalignment check during `alignas` processing), as layout may be cached without taking into account attributes that may affect it. Differential Revision: https://reviews.llvm.org/D46439 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@332843 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp index 9a1ab4a3c5..e8e3faf757 100644 --- a/lib/Sema/SemaDecl.cpp +++ b/lib/Sema/SemaDecl.cpp @@ -15594,6 +15594,10 @@ void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl, if (!Completed) Record->completeDefinition(); + // Handle attributes before checking the layout. + if (Attr) + ProcessDeclAttributeList(S, Record, Attr); + // We may have deferred checking for a deleted destructor. Check now. if (CXXRecordDecl *CXXRecord = dyn_cast(Record)) { auto *Dtor = CXXRecord->getDestructor(); @@ -15724,9 +15728,6 @@ void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl, CDecl->setIvarRBraceLoc(RBrac); } } - - if (Attr) - ProcessDeclAttributeList(S, Record, Attr); } /// Determine whether the given integral value is representable within diff --git a/test/Layout/itanium-pack-and-align.cpp b/test/Layout/itanium-pack-and-align.cpp new file mode 100644 index 0000000000..64569168e4 --- /dev/null +++ b/test/Layout/itanium-pack-and-align.cpp @@ -0,0 +1,26 @@ +// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm-only -fdump-record-layouts %s \ +// RUN: | FileCheck %s + +struct S { + char x; + int y; +} __attribute__((packed, aligned(8))); + +struct alignas(8) T { + char x; + int y; +} __attribute__((packed)); + +S s; +T t; +// CHECK: 0 | struct T +// CHECK-NEXT: 0 | char x +// CHECK-NEXT: 1 | int y +// CHECK-NEXT: | [sizeof=8, dsize=8, align=8, +// CHECK-NEXT: | nvsize=8, nvalign=8] + +// CHECK: 0 | struct S +// CHECK-NEXT: 0 | char x +// CHECK-NEXT: 1 | int y +// CHECK-NEXT: | [sizeof=8, dsize=8, align=8, +// CHECK-NETX: | nvsize=8, nvalign=8]