[MS ABI] Allow a member pointers' converted type to change
Member pointers in the MS ABI are tricky for a variety of reasons.
The size of a member pointer is indeterminate until the program reaches
a point where the representation is required to be known. However,
*pointers* to member pointers may exist without knowing the pointee
type's representation. In these cases, we synthesize an opaque LLVM
type for the pointee type.
However, we can be in a situation where the underlying member pointer's
representation became known mid-way through the program. To account for
this, we attempted to manicure CodeGen's type-cache so that we can
replace the opaque member pointer type with the real deal while leaving
the pointer types unperturbed. This, unfortunately, is a problematic
approach to take as we will violate CodeGen's invariants.
These violations are mostly harmless but let's do the right thing
instead: invalidate the type-cache if a member pointer's LLVM
representation changes.
This fixes PR26313.
llvm-svn: 258839
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index cdd9d09..f8ae031 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -210,6 +210,10 @@
Gen->CompleteTentativeDefinition(D);
}
+ void AssignInheritanceModel(CXXRecordDecl *RD) override {
+ Gen->AssignInheritanceModel(RD);
+ }
+
void HandleVTable(CXXRecordDecl *RD) override {
Gen->HandleVTable(RD);
}
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index ae46b12..be81719 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -489,6 +489,11 @@
Types.UpdateCompletedType(TD);
}
+void CodeGenModule::RefreshTypeCacheForClass(const CXXRecordDecl *RD) {
+ // Make sure that this type is translated.
+ Types.RefreshTypeCacheForClass(RD);
+}
+
llvm::MDNode *CodeGenModule::getTBAAInfo(QualType QTy) {
if (!TBAA)
return nullptr;
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 046bc2a..74087be3 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -994,6 +994,8 @@
void EmitVTable(CXXRecordDecl *Class);
+ void RefreshTypeCacheForClass(const CXXRecordDecl *Class);
+
/// \brief Appends Opts to the "Linker Options" metadata value.
void AppendLinkerOptions(StringRef Opts);
diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index 09d9bf1..554f9ff 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -272,6 +272,17 @@
DI->completeType(RD);
}
+void CodeGenTypes::RefreshTypeCacheForClass(const CXXRecordDecl *RD) {
+ QualType T = Context.getRecordType(RD);
+ T = Context.getCanonicalType(T);
+
+ const Type *Ty = T.getTypePtr();
+ if (RecordsWithOpaqueMemberPointers.count(Ty)) {
+ TypeCache.clear();
+ RecordsWithOpaqueMemberPointers.clear();
+ }
+}
+
static llvm::Type *getTypeForFormat(llvm::LLVMContext &VMContext,
const llvm::fltSemantics &format,
bool UseNativeHalf = false) {
@@ -603,10 +614,13 @@
}
case Type::MemberPointer: {
- if (!getCXXABI().isMemberPointerConvertible(cast<MemberPointerType>(Ty)))
- return llvm::StructType::create(getLLVMContext());
- ResultType =
- getCXXABI().ConvertMemberPointerType(cast<MemberPointerType>(Ty));
+ auto *MPTy = cast<MemberPointerType>(Ty);
+ if (!getCXXABI().isMemberPointerConvertible(MPTy)) {
+ RecordsWithOpaqueMemberPointers.insert(MPTy->getClass());
+ ResultType = llvm::StructType::create(getLLVMContext());
+ } else {
+ ResultType = getCXXABI().ConvertMemberPointerType(MPTy);
+ }
break;
}
diff --git a/clang/lib/CodeGen/CodeGenTypes.h b/clang/lib/CodeGen/CodeGenTypes.h
index a96f23c..a673fa6 100644
--- a/clang/lib/CodeGen/CodeGenTypes.h
+++ b/clang/lib/CodeGen/CodeGenTypes.h
@@ -162,6 +162,8 @@
/// corresponding llvm::Type.
llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
+ llvm::SmallSet<const Type *, 8> RecordsWithOpaqueMemberPointers;
+
public:
CodeGenTypes(CodeGenModule &cgm);
~CodeGenTypes();
@@ -214,6 +216,10 @@
/// replace the 'opaque' type we previously made for it if applicable.
void UpdateCompletedType(const TagDecl *TD);
+ /// \brief Remove stale types from the type cache when an inheritance model
+ /// gets assigned to a class.
+ void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
+
/// getNullaryFunctionInfo - Get the function info for a void()
/// function with standard CC.
const CGFunctionInfo &arrangeNullaryFunction();
diff --git a/clang/lib/CodeGen/ModuleBuilder.cpp b/clang/lib/CodeGen/ModuleBuilder.cpp
index bce19ab..9428bdf 100644
--- a/clang/lib/CodeGen/ModuleBuilder.cpp
+++ b/clang/lib/CodeGen/ModuleBuilder.cpp
@@ -210,6 +210,13 @@
Builder->Release();
}
+ void AssignInheritanceModel(CXXRecordDecl *RD) override {
+ if (Diags.hasErrorOccurred())
+ return;
+
+ Builder->RefreshTypeCacheForClass(RD);
+ }
+
void CompleteTentativeDefinition(VarDecl *D) override {
if (Diags.hasErrorOccurred())
return;