[IR] Deprecate opaque pointer compatibility APIs

This deprecates various compatibility APIs that have been
introduced as part of the opaque pointer migration.

These will be removed at some point after the LLVM 17 release.

Differential Revision: https://reviews.llvm.org/D155585

llvm/include/llvm/IR/DerivedTypes.h

@@ -644,8 +644,6 @@ class PointerType : public Type {
   explicit PointerType(Type *ElType, unsigned AddrSpace);
   explicit PointerType(LLVMContext &C, unsigned AddrSpace);
 
-  Type *PointeeTy;
-
 public:
   PointerType(const PointerType &) = delete;
   PointerType &operator=(const PointerType &) = delete;
@@ -674,14 +672,14 @@ public:
   /// given address space. This is only useful during the opaque pointer
   /// transition.
   /// TODO: remove after opaque pointer transition is complete.
+  [[deprecated("Use PointerType::get() with LLVMContext argument instead")]]
   static PointerType *getWithSamePointeeType(PointerType *PT,
                                              unsigned AddressSpace) {
-    if (PT->isOpaque())
-      return get(PT->getContext(), AddressSpace);
-    return get(PT->PointeeTy, AddressSpace);
+    return get(PT->getContext(), AddressSpace);
   }
 
-  bool isOpaque() const { return !PointeeTy; }
+  [[deprecated("Always returns true")]]
+  bool isOpaque() const { return true; }
 
   /// Return true if the specified type is valid as a element type.
   static bool isValidElementType(Type *ElemTy);
@@ -696,16 +694,18 @@ public:
   /// type matches Ty. Primarily used for checking if an instruction's pointer
   /// operands are valid types. Will be useless after non-opaque pointers are
   /// removed.
-  bool isOpaqueOrPointeeTypeMatches(Type *Ty) {
-    return isOpaque() || PointeeTy == Ty;
+  [[deprecated("Always returns true")]]
+  bool isOpaqueOrPointeeTypeMatches(Type *) {
+    return true;
   }
 
   /// Return true if both pointer types have the same element type. Two opaque
   /// pointers are considered to have the same element type, while an opaque
   /// and a non-opaque pointer have different element types.
   /// TODO: Remove after opaque pointer transition is complete.
+  [[deprecated("Always returns true")]]
   bool hasSameElementTypeAs(PointerType *Other) {
-    return PointeeTy == Other->PointeeTy;
+    return true;
   }
 
   /// Implement support type inquiry through isa, cast, and dyn_cast.

llvm/include/llvm/IR/LLVMContext.h

@@ -316,9 +316,11 @@ public:
   /// times, but only with the same value. Note that creating a pointer type or
   /// otherwise querying the opaque pointer mode performs an implicit set to
   /// the default value.
+  [[deprecated("Opaque pointers are always enabled")]]
   void setOpaquePointers(bool Enable) const;
 
   /// Whether typed pointers are supported. If false, all pointers are opaque.
+  [[deprecated("Always returns false")]]
   bool supportsTypedPointers() const;
 
 private:

llvm/include/llvm/IR/Type.h

@@ -256,7 +256,8 @@ public:
   bool isPointerTy() const { return getTypeID() == PointerTyID; }
 
   /// True if this is an instance of an opaque PointerType.
-  bool isOpaquePointerTy() const;
+  LLVM_DEPRECATED("Use isPointerTy() instead", "isPointerTy")
+  bool isOpaquePointerTy() const { return isPointerTy(); };
 
   /// Return true if this is a pointer type or a vector of pointer types.
   bool isPtrOrPtrVectorTy() const { return getScalarType()->isPointerTy(); }
@@ -411,11 +412,9 @@ public:
   /// Only use this method in code that is not reachable with opaque pointers,
   /// or part of deprecated methods that will be removed as part of the opaque
   /// pointers transition.
+  [[deprecated("Pointers no longer have element types")]]
   Type *getNonOpaquePointerElementType() const {
-    assert(getTypeID() == PointerTyID);
-    assert(NumContainedTys &&
-           "Attempting to get element type of opaque pointer");
-    return ContainedTys[0];
+    llvm_unreachable("Pointers no longer have element types");
   }
 
   /// Given vector type, change the element type,

llvm/lib/IR/Type.cpp

@@ -57,12 +57,6 @@ bool Type::isIntegerTy(unsigned Bitwidth) const {
   return isIntegerTy() && cast<IntegerType>(this)->getBitWidth() == Bitwidth;
 }
 
-bool Type::isOpaquePointerTy() const {
-  if (auto *PTy = dyn_cast<PointerType>(this))
-    return PTy->isOpaque();
-  return false;
-}
-
 bool Type::isScalableTy() const {
   if (const auto *STy = dyn_cast<StructType>(this)) {
     SmallPtrSet<Type *, 4> Visited;
@@ -814,15 +808,8 @@ PointerType *PointerType::get(LLVMContext &C, unsigned AddressSpace) {
   return Entry;
 }
 
-PointerType::PointerType(Type *E, unsigned AddrSpace)
-  : Type(E->getContext(), PointerTyID), PointeeTy(E) {
-  ContainedTys = &PointeeTy;
-  NumContainedTys = 1;
-  setSubclassData(AddrSpace);
-}
-
 PointerType::PointerType(LLVMContext &C, unsigned AddrSpace)
-    : Type(C, PointerTyID), PointeeTy(nullptr) {
+    : Type(C, PointerTyID) {
   setSubclassData(AddrSpace);
 }
 

llvm/unittests/AsmParser/AsmParserTest.cpp

@@ -252,9 +252,6 @@ TEST(AsmParserTest, TypeWithSlotMappingParsing) {
   ASSERT_TRUE(Ty);
   ASSERT_TRUE(Ty->isPointerTy());
 
-  PointerType *PT = cast<PointerType>(Ty);
-  ASSERT_TRUE(PT->isOpaque());
-
   // Check that we reject types with garbage.
   Ty = parseType("i32 garbage", Error, M, &Mapping);
   ASSERT_TRUE(!Ty);
@@ -370,9 +367,6 @@ TEST(AsmParserTest, TypeAtBeginningWithSlotMappingParsing) {
   ASSERT_TRUE(Ty->isPointerTy());
   ASSERT_TRUE(Read == 3);
 
-  PointerType *PT = cast<PointerType>(Ty);
-  ASSERT_TRUE(PT->isOpaque());
-
   // Check that we reject types with garbage.
   Ty = parseTypeAtBeginning("i32 garbage", Read, Error, M, &Mapping);
   ASSERT_TRUE(Ty);