[MS ABI] Refactor member pointer generation
The MS ABI has very complicated member pointers. Don't attempt to
synthesize the final member pointer ab ovo usque ad mala in one go.
Instead, start with a member pointer which points to the declaration in
question as-if it's decl context was the target class. Then, utilize
our conversion logical to convert it to the target type.
This allows us to simplify how we think about member pointers because we
don't need to consider non-zero nv adjustments before we even generate
the member pointer. Furthermore, it gives our adjustment logic more
exposure by utilizing it in a common path.
llvm-svn: 240383
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 07d8842..3c0aeca 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -502,10 +502,6 @@
CharUnits NonVirtualBaseAdjustment,
unsigned VBTableIndex);
- llvm::Constant *BuildMemberPointer(const CXXRecordDecl *RD,
- const CXXMethodDecl *MD,
- CharUnits NonVirtualBaseAdjustment);
-
bool MemberPointerConstantIsNull(const MemberPointerType *MPT,
llvm::Constant *MP);
@@ -570,6 +566,11 @@
llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
llvm::Constant *Src) override;
+ llvm::Constant *EmitMemberPointerConversion(
+ const MemberPointerType *SrcTy, const MemberPointerType *DstTy,
+ CastKind CK, CastExpr::path_const_iterator PathBegin,
+ CastExpr::path_const_iterator PathEnd, llvm::Constant *Src);
+
llvm::Value *
EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, const Expr *E,
llvm::Value *&This, llvm::Value *MemPtr,
@@ -2479,38 +2480,67 @@
CharUnits::Zero(), /*VBTableIndex=*/0);
}
-llvm::Constant *
-MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
- return BuildMemberPointer(MD->getParent(), MD, CharUnits::Zero());
-}
-
llvm::Constant *MicrosoftCXXABI::EmitMemberPointer(const APValue &MP,
QualType MPType) {
- const MemberPointerType *MPT = MPType->castAs<MemberPointerType>();
+ const MemberPointerType *DstTy = MPType->castAs<MemberPointerType>();
const ValueDecl *MPD = MP.getMemberPointerDecl();
if (!MPD)
- return EmitNullMemberPointer(MPT);
+ return EmitNullMemberPointer(DstTy);
- CharUnits ThisAdjustment = getMemberPointerPathAdjustment(MP);
+ ASTContext &Ctx = getContext();
+ ArrayRef<const CXXRecordDecl *> MemberPointerPath = MP.getMemberPointerPath();
- // FIXME PR15713: Support virtual inheritance paths.
+ llvm::Constant *C;
+ if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD)) {
+ C = EmitMemberFunctionPointer(MD);
+ } else {
+ CharUnits FieldOffset = Ctx.toCharUnitsFromBits(Ctx.getFieldOffset(MPD));
+ C = EmitMemberDataPointer(DstTy, FieldOffset);
+ }
- if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MPD))
- return BuildMemberPointer(MPT->getMostRecentCXXRecordDecl(), MD,
- ThisAdjustment);
+ if (!MemberPointerPath.empty()) {
+ const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(MPD->getDeclContext());
+ const Type *SrcRecTy = Ctx.getTypeDeclType(SrcRD).getTypePtr();
+ const MemberPointerType *SrcTy =
+ Ctx.getMemberPointerType(DstTy->getPointeeType(), SrcRecTy)
+ ->castAs<MemberPointerType>();
- CharUnits FieldOffset =
- getContext().toCharUnitsFromBits(getContext().getFieldOffset(MPD));
- return EmitMemberDataPointer(MPT, ThisAdjustment + FieldOffset);
+ bool DerivedMember = MP.isMemberPointerToDerivedMember();
+ SmallVector<const CXXBaseSpecifier *, 4> DerivedToBasePath;
+ const CXXRecordDecl *PrevRD = SrcRD;
+ for (const CXXRecordDecl *PathElem : MemberPointerPath) {
+ const CXXRecordDecl *Base = nullptr;
+ const CXXRecordDecl *Derived = nullptr;
+ if (DerivedMember) {
+ Base = PathElem;
+ Derived = PrevRD;
+ } else {
+ Base = PrevRD;
+ Derived = PathElem;
+ }
+ for (const CXXBaseSpecifier &BS : Derived->bases())
+ if (BS.getType()->getAsCXXRecordDecl()->getCanonicalDecl() ==
+ Base->getCanonicalDecl())
+ DerivedToBasePath.push_back(&BS);
+ PrevRD = PathElem;
+ }
+ assert(DerivedToBasePath.size() == MemberPointerPath.size());
+
+ CastKind CK = DerivedMember ? CK_DerivedToBaseMemberPointer
+ : CK_BaseToDerivedMemberPointer;
+ C = EmitMemberPointerConversion(SrcTy, DstTy, CK, DerivedToBasePath.begin(),
+ DerivedToBasePath.end(), C);
+ }
+ return C;
}
llvm::Constant *
-MicrosoftCXXABI::BuildMemberPointer(const CXXRecordDecl *RD,
- const CXXMethodDecl *MD,
- CharUnits NonVirtualBaseAdjustment) {
+MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
assert(MD->isInstance() && "Member function must not be static!");
+
MD = MD->getCanonicalDecl();
- RD = RD->getMostRecentDecl();
+ CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
+ const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
CodeGenTypes &Types = CGM.getTypes();
unsigned VBTableIndex = 0;
@@ -2923,9 +2953,22 @@
MicrosoftCXXABI::EmitMemberPointerConversion(const CastExpr *E,
llvm::Constant *Src) {
const MemberPointerType *SrcTy =
- E->getSubExpr()->getType()->castAs<MemberPointerType>();
+ E->getSubExpr()->getType()->castAs<MemberPointerType>();
const MemberPointerType *DstTy = E->getType()->castAs<MemberPointerType>();
+ CastKind CK = E->getCastKind();
+
+ return EmitMemberPointerConversion(SrcTy, DstTy, CK, E->path_begin(),
+ E->path_end(), Src);
+}
+
+llvm::Constant *MicrosoftCXXABI::EmitMemberPointerConversion(
+ const MemberPointerType *SrcTy, const MemberPointerType *DstTy, CastKind CK,
+ CastExpr::path_const_iterator PathBegin,
+ CastExpr::path_const_iterator PathEnd, llvm::Constant *Src) {
+ assert(CK == CK_DerivedToBaseMemberPointer ||
+ CK == CK_BaseToDerivedMemberPointer ||
+ CK == CK_ReinterpretMemberPointer);
// If src is null, emit a new null for dst. We can't return src because dst
// might have a new representation.
if (MemberPointerConstantIsNull(SrcTy, Src))
@@ -2934,7 +2977,7 @@
// We don't need to do anything for reinterpret_casts of non-null member
// pointers. We should only get here when the two type representations have
// the same size.
- if (E->getCastKind() == CK_ReinterpretMemberPointer)
+ if (CK == CK_ReinterpretMemberPointer)
return Src;
MSInheritanceAttr::Spelling SrcInheritance = getInheritanceFromMemptr(SrcTy);
@@ -2960,12 +3003,16 @@
// For data pointers, we adjust the field offset directly. For functions, we
// have a separate field.
- llvm::Constant *Adj = getMemberPointerAdjustment(E);
+ const MemberPointerType *DerivedTy =
+ CK == CK_DerivedToBaseMemberPointer ? SrcTy : DstTy;
+ const CXXRecordDecl *DerivedClass = DerivedTy->getMostRecentCXXRecordDecl();
+ llvm::Constant *Adj =
+ CGM.GetNonVirtualBaseClassOffset(DerivedClass, PathBegin, PathEnd);
if (Adj) {
Adj = llvm::ConstantExpr::getTruncOrBitCast(Adj, CGM.IntTy);
llvm::Constant *&NVAdjustField =
IsFunc ? NonVirtualBaseAdjustment : FirstField;
- bool IsDerivedToBase = (E->getCastKind() == CK_DerivedToBaseMemberPointer);
+ bool IsDerivedToBase = (CK == CK_DerivedToBaseMemberPointer);
if (!NVAdjustField) // If this field didn't exist in src, it's zero.
NVAdjustField = getZeroInt();
if (IsDerivedToBase)