This revision was automatically updated to reflect the committed changes.
Closed by commit rGad59735f9d15: Fix __has_unique_object_representations with
no_unique_address (authored by gbencze, committed by steakhal).
Changed prior to commit:
https://reviews.llvm.org/D89649?vs=303082&id=368823#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D89649/new/
https://reviews.llvm.org/D89649
Files:
clang/lib/AST/ASTContext.cpp
clang/test/SemaCXX/has_unique_object_reps_no_unique_addr.cpp
Index: clang/test/SemaCXX/has_unique_object_reps_no_unique_addr.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/has_unique_object_reps_no_unique_addr.cpp
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify -std=c++2a %s
+// expected-no-diagnostics
+
+struct Empty {};
+
+struct A {
+ [[no_unique_address]] Empty e;
+ char x;
+};
+
+static_assert(__has_unique_object_representations(A));
+
+struct B {
+ char x;
+ [[no_unique_address]] Empty e;
+};
+
+static_assert(__has_unique_object_representations(B));
+
+struct C {
+ char x;
+ [[no_unique_address]] Empty e1;
+ [[no_unique_address]] Empty e2;
+};
+
+static_assert(!__has_unique_object_representations(C));
+
+namespace TailPaddingReuse {
+struct A {
+private:
+ int a;
+
+public:
+ char b;
+};
+
+struct B {
+ [[no_unique_address]] A a;
+ char c[3];
+};
+} // namespace TailPaddingReuse
+static_assert(__has_unique_object_representations(TailPaddingReuse::B));
Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -2633,16 +2633,66 @@
return !RD->field_empty();
}
-static bool isStructEmpty(QualType Ty) {
- const RecordDecl *RD = Ty->castAs<RecordType>()->getDecl();
+static int64_t getSubobjectOffset(const FieldDecl *Field,
+ const ASTContext &Context,
+ const clang::ASTRecordLayout & /*Layout*/) {
+ return Context.getFieldOffset(Field);
+}
- if (!RD->field_empty())
- return false;
+static int64_t getSubobjectOffset(const CXXRecordDecl *RD,
+ const ASTContext &Context,
+ const clang::ASTRecordLayout &Layout) {
+ return Context.toBits(Layout.getBaseClassOffset(RD));
+}
- if (const auto *ClassDecl = dyn_cast<CXXRecordDecl>(RD))
- return ClassDecl->isEmpty();
+static llvm::Optional<int64_t>
+structHasUniqueObjectRepresentations(const ASTContext &Context,
+ const RecordDecl *RD);
- return true;
+static llvm::Optional<int64_t>
+getSubobjectSizeInBits(const FieldDecl *Field, const ASTContext &Context) {
+ if (Field->getType()->isRecordType()) {
+ const RecordDecl *RD = Field->getType()->getAsRecordDecl();
+ if (!RD->isUnion())
+ return structHasUniqueObjectRepresentations(Context, RD);
+ }
+ if (!Field->getType()->isReferenceType() &&
+ !Context.hasUniqueObjectRepresentations(Field->getType()))
+ return llvm::None;
+
+ int64_t FieldSizeInBits =
+ Context.toBits(Context.getTypeSizeInChars(Field->getType()));
+ if (Field->isBitField()) {
+ int64_t BitfieldSize = Field->getBitWidthValue(Context);
+ if (BitfieldSize > FieldSizeInBits)
+ return llvm::None;
+ FieldSizeInBits = BitfieldSize;
+ }
+ return FieldSizeInBits;
+}
+
+static llvm::Optional<int64_t>
+getSubobjectSizeInBits(const CXXRecordDecl *RD, const ASTContext &Context) {
+ return structHasUniqueObjectRepresentations(Context, RD);
+}
+
+template <typename RangeT>
+static llvm::Optional<int64_t> structSubobjectsHaveUniqueObjectRepresentations(
+ const RangeT &Subobjects, int64_t CurOffsetInBits,
+ const ASTContext &Context, const clang::ASTRecordLayout &Layout) {
+ for (const auto *Subobject : Subobjects) {
+ llvm::Optional<int64_t> SizeInBits =
+ getSubobjectSizeInBits(Subobject, Context);
+ if (!SizeInBits)
+ return llvm::None;
+ if (*SizeInBits != 0) {
+ int64_t Offset = getSubobjectOffset(Subobject, Context, Layout);
+ if (Offset != CurOffsetInBits)
+ return llvm::None;
+ CurOffsetInBits += *SizeInBits;
+ }
+ }
+ return CurOffsetInBits;
}
static llvm::Optional<int64_t>
@@ -2656,58 +2706,32 @@
if (ClassDecl->isDynamicClass())
return llvm::None;
- SmallVector<std::pair<QualType, int64_t>, 4> Bases;
+ SmallVector<CXXRecordDecl *, 4> Bases;
for (const auto &Base : ClassDecl->bases()) {
// Empty types can be inherited from, and non-empty types can potentially
// have tail padding, so just make sure there isn't an error.
- if (!isStructEmpty(Base.getType())) {
- llvm::Optional<int64_t> Size = structHasUniqueObjectRepresentations(
- Context, Base.getType()->castAs<RecordType>()->getDecl());
- if (!Size)
- return llvm::None;
- Bases.emplace_back(Base.getType(), Size.getValue());
- }
+ Bases.emplace_back(Base.getType()->getAsCXXRecordDecl());
}
- llvm::sort(Bases, [&](const std::pair<QualType, int64_t> &L,
- const std::pair<QualType, int64_t> &R) {
- return Layout.getBaseClassOffset(L.first->getAsCXXRecordDecl()) <
- Layout.getBaseClassOffset(R.first->getAsCXXRecordDecl());
+ llvm::sort(Bases, [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
+ return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
});
- for (const auto &Base : Bases) {
- int64_t BaseOffset = Context.toBits(
- Layout.getBaseClassOffset(Base.first->getAsCXXRecordDecl()));
- int64_t BaseSize = Base.second;
- if (BaseOffset != CurOffsetInBits)
- return llvm::None;
- CurOffsetInBits = BaseOffset + BaseSize;
- }
- }
-
- for (const auto *Field : RD->fields()) {
- if (!Field->getType()->isReferenceType() &&
- !Context.hasUniqueObjectRepresentations(Field->getType()))
- return llvm::None;
-
- int64_t FieldSizeInBits =
- Context.toBits(Context.getTypeSizeInChars(Field->getType()));
- if (Field->isBitField()) {
- int64_t BitfieldSize = Field->getBitWidthValue(Context);
-
- if (BitfieldSize > FieldSizeInBits)
- return llvm::None;
- FieldSizeInBits = BitfieldSize;
- }
-
- int64_t FieldOffsetInBits = Context.getFieldOffset(Field);
-
- if (FieldOffsetInBits != CurOffsetInBits)
+ llvm::Optional<int64_t> OffsetAfterBases =
+ structSubobjectsHaveUniqueObjectRepresentations(Bases, CurOffsetInBits,
+ Context, Layout);
+ if (!OffsetAfterBases)
return llvm::None;
-
- CurOffsetInBits = FieldSizeInBits + FieldOffsetInBits;
+ CurOffsetInBits = *OffsetAfterBases;
}
+ llvm::Optional<int64_t> OffsetAfterFields =
+ structSubobjectsHaveUniqueObjectRepresentations(
+ RD->fields(), CurOffsetInBits, Context, Layout);
+ if (!OffsetAfterFields)
+ return llvm::None;
+ CurOffsetInBits = *OffsetAfterFields;
+
return CurOffsetInBits;
}
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