Author: andersca
Date: Sat May 29 14:44:50 2010
New Revision: 105110
URL: http://llvm.org/viewvc/llvm-project?rev=105110&view=rev
Log:
Rework the way virtual primary bases are added when laying out classes. Instead
of doing it as a separate step, we now use the BaseSubobjectInfo and use it
when laying out the bases. This fixes a bug where we would either not add a
primary virtual base at all, or add it at the wrong offset.
Modified:
cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
cfe/trunk/test/SemaCXX/class-layout.cpp
Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=105110&r1=105109&r2=105110&view=diff
==============================================================================
--- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
+++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Sat May 29 14:44:50 2010
@@ -571,8 +571,8 @@
/// LayoutNonVirtualBase - Lays out a single non-virtual base.
void LayoutNonVirtualBase(const BaseSubobjectInfo *Base);
- void AddPrimaryVirtualBaseOffsets(const CXXRecordDecl *RD, uint64_t Offset,
- const CXXRecordDecl *MostDerivedClass);
+ void AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
+ uint64_t Offset);
/// LayoutVirtualBases - Lays out all the virtual bases.
void LayoutVirtualBases(const CXXRecordDecl *RD,
@@ -926,62 +926,42 @@
// Add its base class offset.
assert(!Bases.count(Base->Class) && "base offset already exists!");
Bases.insert(std::make_pair(Base->Class, Offset));
+
+ AddPrimaryVirtualBaseOffsets(Base, Offset);
}
void
-RecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(const CXXRecordDecl *RD,
- uint64_t Offset,
- const CXXRecordDecl *MostDerivedClass)
{
- // We already have the offset for the primary base of the most derived class.
- if (RD != MostDerivedClass) {
- const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
- const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
+RecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo
*Info,
+ uint64_t Offset) {
+ // This base isn't interesting, it has no virtual bases.
+ if (!Info->Class->getNumVBases())
+ return;
+
+ // First, check if we have a virtual primary base to add offsets for.
+ if (Info->PrimaryVirtualBaseInfo) {
+ assert(Info->PrimaryVirtualBaseInfo->IsVirtual &&
+ "Primary virtual base is not virtual!");
+ if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
+ // Add the offset.
+ assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
+ "primary vbase offset already exists!");
+ VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
+ Offset));
- // If this is a primary virtual base and we haven't seen it before, add it.
- if (PrimaryBase && Layout.getPrimaryBaseWasVirtual() &&
- !VBases.count(PrimaryBase))
- VBases.insert(std::make_pair(PrimaryBase, Offset));
+ // Traverse the primary virtual base.
+ AddPrimaryVirtualBaseOffsets(Info->PrimaryVirtualBaseInfo, Offset);
+ }
}
- for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
- E = RD->bases_end(); I != E; ++I) {
- assert(!I->getType()->isDependentType() &&
- "Cannot layout class with dependent bases.");
-
- const CXXRecordDecl *BaseDecl =
- cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
-
- if (!BaseDecl->getNumVBases()) {
- // This base isn't interesting since it doesn't have any virtual bases.
+ // Now go through all direct non-virtual bases.
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
+ for (unsigned I = 0, E = Info->Bases.size(); I != E; ++I) {
+ const BaseSubobjectInfo *Base = Info->Bases[I];
+ if (Base->IsVirtual)
continue;
- }
-
- // Compute the offset of this base.
- uint64_t BaseOffset;
-
- if (I->isVirtual()) {
- // If we don't know this vbase yet, don't visit it. It will be visited
- // later.
- if (!VBases.count(BaseDecl)) {
- continue;
- }
- // Check if we've already visited this base.
- if (!VisitedVirtualBases.insert(BaseDecl))
- continue;
-
- // We want the vbase offset from the class we're currently laying out.
- BaseOffset = VBases[BaseDecl];
- } else if (RD == MostDerivedClass) {
- // We want the base offset from the class we're currently laying out.
- assert(Bases.count(BaseDecl) && "Did not find base!");
- BaseOffset = Bases[BaseDecl];
- } else {
- const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
- BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
- }
-
- AddPrimaryVirtualBaseOffsets(BaseDecl, BaseOffset, MostDerivedClass);
+ uint64_t BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
+ AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
}
}
@@ -1035,12 +1015,16 @@
}
void RecordLayoutBuilder::LayoutVirtualBase(const BaseSubobjectInfo *Base) {
+ assert(!Base->Derived && "Trying to lay out a primary virtual base!");
+
// Layout the base.
uint64_t Offset = LayoutBase(Base->Class, /*BaseIsVirtual=*/true);
// Add its base class offset.
assert(!VBases.count(Base->Class) && "vbase offset already exists!");
VBases.insert(std::make_pair(Base->Class, Offset));
+
+ AddPrimaryVirtualBaseOffsets(Base, Offset);
}
uint64_t RecordLayoutBuilder::LayoutBase(const CXXRecordDecl *Base,
@@ -1298,7 +1282,6 @@
LayoutVirtualBases(RD, RD);
VisitedVirtualBases.clear();
- AddPrimaryVirtualBaseOffsets(RD, 0, RD);
// Finally, round the size of the total struct up to the alignment of the
// struct itself.
Modified: cfe/trunk/test/SemaCXX/class-layout.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/class-layout.cpp?rev=105110&r1=105109&r2=105110&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/class-layout.cpp (original)
+++ cfe/trunk/test/SemaCXX/class-layout.cpp Sat May 29 14:44:50 2010
@@ -71,3 +71,17 @@
SA(10, sizeof(D) == 2);
}
+
+namespace Test1 {
+
+// Test that we don't assert on this hierarchy.
+struct A { };
+struct B : A { virtual void b(); };
+class C : virtual A { int c; };
+struct D : virtual B { };
+struct E : C, virtual D { };
+class F : virtual E { };
+struct G : virtual E, F { };
+
+SA(0, sizeof(G) == 24);
+}
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