MS ABI: Insert copy-constructors into the CatchableType

Find all unambiguous public classes of the exception object's class type
and reference all of their copy constructors.  Yes, this is not
conforming but it is necessary in order to implement their ABI.  This is
because the copy constructor is actually referenced by the metadata
describing which catch handlers are eligible to handle the exception
object.

N.B.  This doesn't yet handle the copy constructor closure case yet,
that work is ongoing.

Differential Revision: http://reviews.llvm.org/D8101

llvm-svn: 231499

7 files changed, 150 insertions, 30 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index fc40f7e8e23..9cfc97b926d 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -8189,6 +8189,19 @@ MangleNumberingContext *ASTContext::createMangleNumberingContext() const {
   return ABI->createMangleNumberingContext();
 }
 
+const CXXConstructorDecl *
+ASTContext::getCopyConstructorForExceptionObject(CXXRecordDecl *RD) {
+  return ABI->getCopyConstructorForExceptionObject(
+      cast<CXXRecordDecl>(RD->getFirstDecl()));
+}
+
+void ASTContext::addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
+                                                      CXXConstructorDecl *CD) {
+  return ABI->addCopyConstructorForExceptionObject(
+      cast<CXXRecordDecl>(RD->getFirstDecl()),
+      cast<CXXConstructorDecl>(CD->getFirstDecl()));
+}
+
 void ASTContext::setParameterIndex(const ParmVarDecl *D, unsigned int index) {
   ParamIndices[D] = index;
 }
diff --git a/clang/lib/AST/CXXABI.h b/clang/lib/AST/CXXABI.h
index 8e9e358525e..62c96f901e6 100644
--- a/clang/lib/AST/CXXABI.h
+++ b/clang/lib/AST/CXXABI.h
@@ -20,6 +20,7 @@
 namespace clang {
 
 class ASTContext;
+class CXXConstructorDecl;
 class MemberPointerType;
 class MangleNumberingContext;
 
@@ -41,6 +42,14 @@ public:
 
   /// Returns a new mangling number context for this C++ ABI.
   virtual MangleNumberingContext *createMangleNumberingContext() const = 0;
+
+  /// Adds a mapping from class to copy constructor for this C++ ABI.
+  virtual void addCopyConstructorForExceptionObject(CXXRecordDecl *,
+                                                    CXXConstructorDecl *) = 0;
+
+  /// Retrieves the mapping from class to copy constructor for this C++ ABI.
+  virtual const CXXConstructorDecl *
+  getCopyConstructorForExceptionObject(CXXRecordDecl *) = 0;
 };
 
 /// Creates an instance of a C++ ABI class.
diff --git a/clang/lib/AST/ItaniumCXXABI.cpp b/clang/lib/AST/ItaniumCXXABI.cpp
index 378121c8e5b..13d4dbf1f46 100644
--- a/clang/lib/AST/ItaniumCXXABI.cpp
+++ b/clang/lib/AST/ItaniumCXXABI.cpp
@@ -133,6 +133,14 @@ public:
     return Layout.getNonVirtualSize() == PointerSize;
   }
 
+  const CXXConstructorDecl *
+  getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
+    return nullptr;
+  }
+
+  void addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
+                                            CXXConstructorDecl *CD) override {}
+
   MangleNumberingContext *createMangleNumberingContext() const override {
     return new ItaniumNumberingContext();
   }
diff --git a/clang/lib/AST/MicrosoftCXXABI.cpp b/clang/lib/AST/MicrosoftCXXABI.cpp
index 0603d3b7b9b..71b21bff77c 100644
--- a/clang/lib/AST/MicrosoftCXXABI.cpp
+++ b/clang/lib/AST/MicrosoftCXXABI.cpp
@@ -63,6 +63,8 @@ public:
 
 class MicrosoftCXXABI : public CXXABI {
   ASTContext &Context;
+  llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> RecordToCopyCtor;
+
 public:
   MicrosoftCXXABI(ASTContext &Ctx) : Context(Ctx) { }
 
@@ -82,13 +84,26 @@ public:
       return false;
 
     const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
-    
+
     // In the Microsoft ABI, classes can have one or two vtable pointers.
-    CharUnits PointerSize = 
-      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
+    CharUnits PointerSize =
+        Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
     return Layout.getNonVirtualSize() == PointerSize ||
       Layout.getNonVirtualSize() == PointerSize * 2;
-  }    
+  }
+
+  const CXXConstructorDecl *
+  getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
+    return RecordToCopyCtor[RD];
+  }
+
+  void
+  addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
+                                       CXXConstructorDecl *CD) override {
+    assert(CD != nullptr);
+    assert(RecordToCopyCtor[RD] == nullptr || RecordToCopyCtor[RD] == CD);
+    RecordToCopyCtor[RD] = CD;
+  }
 
   MangleNumberingContext *createMangleNumberingContext() const override {
     return new MicrosoftNumberingContext();
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 29af2cb9c2c..3f660c9f69e 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -114,8 +114,8 @@ public:
                           uint32_t NumEntries, raw_ostream &Out) override;
   void mangleCXXCatchableTypeArray(QualType T, uint32_t NumEntries,
                                    raw_ostream &Out) override;
-  void mangleCXXCatchableType(QualType T, uint32_t Size,
-                              raw_ostream &Out) override;
+  void mangleCXXCatchableType(QualType T, const CXXConstructorDecl *CD,
+                              uint32_t Size, raw_ostream &Out) override;
   void mangleCXXRTTI(QualType T, raw_ostream &Out) override;
   void mangleCXXRTTIName(QualType T, raw_ostream &Out) override;
   void mangleCXXRTTIBaseClassDescriptor(const CXXRecordDecl *Derived,
@@ -2307,13 +2307,25 @@ void MicrosoftMangleContextImpl::mangleCXXCatchableTypeArray(
   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
 }
 
-void MicrosoftMangleContextImpl::mangleCXXCatchableType(QualType T,
-                                                        uint32_t Size,
-                                                        raw_ostream &Out) {
+void MicrosoftMangleContextImpl::mangleCXXCatchableType(
+    QualType T, const CXXConstructorDecl *CD, uint32_t Size, raw_ostream &Out) {
   MicrosoftCXXNameMangler Mangler(*this, Out);
-  Mangler.getStream() << "_CT??_R0";
-  Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
-  Mangler.getStream() << "@8";
+  Mangler.getStream() << "_CT";
+
+  llvm::SmallString<64> RTTIMangling;
+  {
+    llvm::raw_svector_ostream Stream(RTTIMangling);
+    mangleCXXRTTI(T, Stream);
+  }
+  Mangler.getStream() << RTTIMangling.substr(1);
+
+  llvm::SmallString<64> CopyCtorMangling;
+  if (CD) {
+    llvm::raw_svector_ostream Stream(CopyCtorMangling);
+    mangleCXXCtor(CD, Ctor_Complete, Stream);
+  }
+  Mangler.getStream() << CopyCtorMangling.substr(1);
+
   Mangler.getStream() << Size;
 }
 
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index dd4c274e245..4e3d50b408e 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -17,6 +17,7 @@
 #include "CGCXXABI.h"
 #include "CGVTables.h"
 #include "CodeGenModule.h"
+#include "CodeGenTypes.h"
 #include "TargetInfo.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
@@ -3225,11 +3226,14 @@ llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
                                                   uint32_t VBIndex) {
   assert(!T->isReferenceType());
 
+  CXXRecordDecl *RD = T->getAsCXXRecordDecl();
+  const CXXConstructorDecl *CD =
+      RD ? CGM.getContext().getCopyConstructorForExceptionObject(RD) : nullptr;
   uint32_t Size = getContext().getTypeSizeInChars(T).getQuantity();
   SmallString<256> MangledName;
   {
     llvm::raw_svector_ostream Out(MangledName);
-    getMangleContext().mangleCXXCatchableType(T, Size, Out);
+    getMangleContext().mangleCXXCatchableType(T, CD, Size, Out);
   }
   if (llvm::GlobalVariable *GV = CGM.getModule().getNamedGlobal(MangledName))
     return getImageRelativeConstant(GV);
@@ -3241,16 +3245,15 @@ llvm::Constant *MicrosoftCXXABI::getCatchableType(QualType T,
   // The runtime is responsible for calling the copy constructor if the
   // exception is caught by value.
   llvm::Constant *CopyCtor =
-      getImageRelativeConstant(llvm::Constant::getNullValue(CGM.Int8PtrTy));
+      CD ? llvm::ConstantExpr::getBitCast(
+               CGM.getAddrOfCXXStructor(CD, StructorType::Complete),
+               CGM.Int8PtrTy)
+         : llvm::Constant::getNullValue(CGM.Int8PtrTy);
+  CopyCtor = getImageRelativeConstant(CopyCtor);
 
-  bool IsScalar = true;
+  bool IsScalar = !RD;
   bool HasVirtualBases = false;
   bool IsStdBadAlloc = false; // std::bad_alloc is special for some reason.
-  if (T->getAsCXXRecordDecl()) {
-    IsScalar = false;
-    // TODO: Fill in the CopyCtor here!  This is not trivial due to
-    // copy-constructors possessing things like default arguments.
-  }
   QualType PointeeType = T;
   if (T->isPointerType())
     PointeeType = T->getPointeeType();
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 29e5150073d..0cedf349b95 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -657,6 +657,55 @@ ExprResult Sema::BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
       CXXThrowExpr(Ex, Context.VoidTy, OpLoc, IsThrownVarInScope);
 }
 
+static void
+collectPublicBases(CXXRecordDecl *RD,
+                   llvm::DenseMap<CXXRecordDecl *, unsigned> &SubobjectsSeen,
+                   llvm::SmallPtrSetImpl<CXXRecordDecl *> &VBases,
+                   llvm::SetVector<CXXRecordDecl *> &PublicSubobjectsSeen,
+                   bool ParentIsPublic) {
+  for (const CXXBaseSpecifier &BS : RD->bases()) {
+    CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
+    bool NewSubobject;
+    // Virtual bases constitute the same subobject.  Non-virtual bases are
+    // always distinct subobjects.
+    if (BS.isVirtual())
+      NewSubobject = VBases.insert(BaseDecl).second;
+    else
+      NewSubobject = true;
+
+    if (NewSubobject)
+      ++SubobjectsSeen[BaseDecl];
+
+    // Only add subobjects which have public access throughout the entire chain.
+    bool PublicPath = ParentIsPublic && BS.getAccessSpecifier() == AS_public;
+    if (PublicPath)
+      PublicSubobjectsSeen.insert(BaseDecl);
+
+    // Recurse on to each base subobject.
+    collectPublicBases(BaseDecl, SubobjectsSeen, VBases, PublicSubobjectsSeen,
+                       PublicPath);
+  }
+}
+
+static void getUnambiguousPublicSubobjects(
+    CXXRecordDecl *RD, llvm::SmallVectorImpl<CXXRecordDecl *> &Objects) {
+  llvm::DenseMap<CXXRecordDecl *, unsigned> SubobjectsSeen;
+  llvm::SmallSet<CXXRecordDecl *, 2> VBases;
+  llvm::SetVector<CXXRecordDecl *> PublicSubobjectsSeen;
+  SubobjectsSeen[RD] = 1;
+  PublicSubobjectsSeen.insert(RD);
+  collectPublicBases(RD, SubobjectsSeen, VBases, PublicSubobjectsSeen,
+                     /*ParentIsPublic=*/true);
+
+  for (CXXRecordDecl *PublicSubobject : PublicSubobjectsSeen) {
+    // Skip ambiguous objects.
+    if (SubobjectsSeen[PublicSubobject] > 1)
+      continue;
+
+    Objects.push_back(PublicSubobject);
+  }
+}
+
 /// CheckCXXThrowOperand - Validate the operand of a throw.
 ExprResult Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *E,
                                       bool IsThrownVarInScope) {
@@ -723,18 +772,29 @@ ExprResult Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *E,
     return E;
 
   // If the class has a destructor, we must be able to call it.
-  if (RD->hasIrrelevantDestructor())
-    return E;
+  if (!RD->hasIrrelevantDestructor()) {
+    if (CXXDestructorDecl *Destructor = LookupDestructor(RD)) {
+      MarkFunctionReferenced(E->getExprLoc(), Destructor);
+      CheckDestructorAccess(E->getExprLoc(), Destructor,
+                            PDiag(diag::err_access_dtor_exception) << Ty);
+      if (DiagnoseUseOfDecl(Destructor, E->getExprLoc()))
+        return ExprError();
+    }
+  }
 
-  CXXDestructorDecl *Destructor = LookupDestructor(RD);
-  if (!Destructor)
-    return E;
+  if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
+    llvm::SmallVector<CXXRecordDecl *, 2> UnambiguousPublicSubobjects;
+    getUnambiguousPublicSubobjects(RD, UnambiguousPublicSubobjects);
+    for (CXXRecordDecl *Subobject : UnambiguousPublicSubobjects) {
+      if (CXXConstructorDecl *CD = LookupCopyingConstructor(Subobject, 0)) {
+        if (CD->isTrivial())
+          continue;
+        MarkFunctionReferenced(E->getExprLoc(), CD);
+        Context.addCopyConstructorForExceptionObject(Subobject, CD);
+      }
+    }
+  }
 
-  MarkFunctionReferenced(E->getExprLoc(), Destructor);
-  CheckDestructorAccess(E->getExprLoc(), Destructor,
-                        PDiag(diag::err_access_dtor_exception) << Ty);
-  if (DiagnoseUseOfDecl(Destructor, E->getExprLoc()))
-    return ExprError();
   return E;
 }