[ms-cxxabi] Implement member pointer emission and dereferencing

Summary:
Handles all inheritance models for both data and function member
pointers.

Also implements isZeroInitializable() and refactors some of the null
member pointer code.

MSVC supports converting member pointers through virtual bases, which
clang does not (yet?) support.  Implementing that extension is covered
by http://llvm.org/15713

Reviewers: rjmccall

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D613

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179305 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 8 deletions

diff --git a/lib/AST/MicrosoftCXXABI.cpp b/lib/AST/MicrosoftCXXABI.cpp
index 6553e9d749..fd932f7330 100644
--- a/lib/AST/MicrosoftCXXABI.cpp
+++ b/lib/AST/MicrosoftCXXABI.cpp
@@ -89,8 +89,8 @@ MSInheritanceModel CXXRecordDecl::getMSInheritanceModel() const {
   if (this->getNumVBases() > 0)
     return MSIM_Virtual;
   if (usesMultipleInheritanceModel(this))
-    return MSIM_Multiple;
-  return MSIM_Single;
+    return this->isPolymorphic() ? MSIM_MultiplePolymorphic : MSIM_Multiple;
+  return this->isPolymorphic() ? MSIM_SinglePolymorphic : MSIM_Single;
 }
 
 // Returns the number of pointer and integer slots used to represent a member
@@ -119,15 +119,15 @@ MSInheritanceModel CXXRecordDecl::getMSInheritanceModel() const {
 //
 //     // The offset of the vb-table pointer within the object.  Only needed for
 //     // incomplete types.
-//     int VBTableOffset;
+//     int VBPtrOffset;
 //   };
-std::pair<unsigned, unsigned>
-MemberPointerType::getMSMemberPointerSlots() const {
-  const CXXRecordDecl *RD = this->getClass()->getAsCXXRecordDecl();
+static std::pair<unsigned, unsigned>
+getMSMemberPointerSlots(const MemberPointerType *MPT) {
+  const CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl();
   MSInheritanceModel Inheritance = RD->getMSInheritanceModel();
   unsigned Ptrs;
   unsigned Ints = 0;
-  if (this->isMemberFunctionPointer()) {
+  if (MPT->isMemberFunctionPointer()) {
     // Member function pointers are a struct of a function pointer followed by a
     // variable number of ints depending on the inheritance model used.  The
     // function pointer is a real function if it is non-virtual and a vftable
@@ -137,7 +137,9 @@ MemberPointerType::getMSMemberPointerSlots() const {
     switch (Inheritance) {
     case MSIM_Unspecified: ++Ints;  // VBTableOffset
     case MSIM_Virtual:     ++Ints;  // VirtualBaseAdjustmentOffset
+    case MSIM_MultiplePolymorphic:
     case MSIM_Multiple:    ++Ints;  // NonVirtualBaseAdjustment
+    case MSIM_SinglePolymorphic:
     case MSIM_Single:      break;   // Nothing
     }
   } else {
@@ -147,7 +149,9 @@ MemberPointerType::getMSMemberPointerSlots() const {
     switch (Inheritance) {
     case MSIM_Unspecified: ++Ints;  // VBTableOffset
     case MSIM_Virtual:     ++Ints;  // VirtualBaseAdjustmentOffset
+    case MSIM_MultiplePolymorphic:
     case MSIM_Multiple:             // Nothing
+    case MSIM_SinglePolymorphic:
     case MSIM_Single:      ++Ints;  // Field offset
     }
   }
@@ -160,7 +164,7 @@ std::pair<uint64_t, unsigned> MicrosoftCXXABI::getMemberPointerWidthAndAlign(
   assert(Target.getTriple().getArch() == llvm::Triple::x86 ||
          Target.getTriple().getArch() == llvm::Triple::x86_64);
   unsigned Ptrs, Ints;
-  llvm::tie(Ptrs, Ints) = MPT->getMSMemberPointerSlots();
+  llvm::tie(Ptrs, Ints) = getMSMemberPointerSlots(MPT);
   // The nominal struct is laid out with pointers followed by ints and aligned
   // to a pointer width if any are present and an int width otherwise.
   unsigned PtrSize = Target.getPointerWidth(0);