[clang][CodeGen] Simplify code based on opaque pointers (#65624)

- Update CodeGenTypeCache to use a single union for all pointers in
  address space zero.
- Introduce a UnqualPtrTy in CodeGenTypeCache, and use that (for
  example instead of llvm::PointerType::getUnqual) in some places.
- Drop some redundant bit/pointers casts from ptr to ptr.

clang/lib/CodeGen/CGAtomic.cpp

@@ -87,8 +87,7 @@ namespace {
         llvm::Value *StoragePtr = CGF.Builder.CreateConstGEP1_64(
             CGF.Int8Ty, BitFieldPtr, OffsetInChars.getQuantity());
         StoragePtr = CGF.Builder.CreateAddrSpaceCast(
-            StoragePtr, llvm::PointerType::getUnqual(CGF.getLLVMContext()),
-            "atomic_bitfield_base");
+            StoragePtr, CGF.UnqualPtrTy, "atomic_bitfield_base");
         BFI = OrigBFI;
         BFI.Offset = Offset;
         BFI.StorageSize = AtomicSizeInBits;

clang/lib/CodeGen/CGBlocks.cpp

@@ -1189,8 +1189,8 @@ RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
     }
   } else {
     // Bitcast the block literal to a generic block literal.
-    BlockPtr = Builder.CreatePointerCast(
-        BlockPtr, llvm::PointerType::get(GenBlockTy, 0), "block.literal");
+    BlockPtr =
+        Builder.CreatePointerCast(BlockPtr, UnqualPtrTy, "block.literal");
     // Get pointer to the block invoke function
     llvm::Value *FuncPtr = Builder.CreateStructGEP(GenBlockTy, BlockPtr, 3);
 
@@ -1208,12 +1208,6 @@ RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
   const CGFunctionInfo &FnInfo =
     CGM.getTypes().arrangeBlockFunctionCall(Args, FuncTy);
 
-  // Cast the function pointer to the right type.
-  llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo);
-
-  llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy);
-  Func = Builder.CreatePointerCast(Func, BlockFTyPtr);
-
   // Prepare the callee.
   CGCallee Callee(CGCalleeInfo(), Func);
 
@@ -2589,11 +2583,11 @@ const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) {
   SmallVector<llvm::Type *, 8> types;
 
   // void *__isa;
-  types.push_back(Int8PtrTy);
+  types.push_back(VoidPtrTy);
   size += getPointerSize();
 
   // void *__forwarding;
-  types.push_back(llvm::PointerType::getUnqual(byrefType));
+  types.push_back(VoidPtrTy);
   size += getPointerSize();
 
   // int32_t __flags;
@@ -2608,11 +2602,11 @@ const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) {
   bool hasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D);
   if (hasCopyAndDispose) {
     /// void *__copy_helper;
-    types.push_back(Int8PtrTy);
+    types.push_back(VoidPtrTy);
     size += getPointerSize();
 
     /// void *__destroy_helper;
-    types.push_back(Int8PtrTy);
+    types.push_back(VoidPtrTy);
     size += getPointerSize();
   }
 
@@ -2621,7 +2615,7 @@ const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) {
   if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) &&
       HasByrefExtendedLayout) {
     /// void *__byref_variable_layout;
-    types.push_back(Int8PtrTy);
+    types.push_back(VoidPtrTy);
     size += CharUnits::fromQuantity(PointerSizeInBytes);
   }
 

clang/lib/CodeGen/CGCUDANV.cpp

@@ -226,18 +226,15 @@ CGNVCUDARuntime::CGNVCUDARuntime(CodeGenModule &CGM)
       TheModule(CGM.getModule()),
       RelocatableDeviceCode(CGM.getLangOpts().GPURelocatableDeviceCode),
       DeviceMC(InitDeviceMC(CGM)) {
-  CodeGen::CodeGenTypes &Types = CGM.getTypes();
-  ASTContext &Ctx = CGM.getContext();
-
   IntTy = CGM.IntTy;
   SizeTy = CGM.SizeTy;
   VoidTy = CGM.VoidTy;
   Zeros[0] = llvm::ConstantInt::get(SizeTy, 0);
   Zeros[1] = Zeros[0];
 
-  CharPtrTy = llvm::PointerType::getUnqual(Types.ConvertType(Ctx.CharTy));
-  VoidPtrTy = cast<llvm::PointerType>(Types.ConvertType(Ctx.VoidPtrTy));
-  VoidPtrPtrTy = llvm::PointerType::getUnqual(CGM.getLLVMContext());
+  CharPtrTy = CGM.UnqualPtrTy;
+  VoidPtrTy = CGM.UnqualPtrTy;
+  VoidPtrPtrTy = CGM.UnqualPtrTy;
 }
 
 llvm::FunctionCallee CGNVCUDARuntime::getSetupArgumentFn() const {

clang/lib/CodeGen/CGExpr.cpp

@@ -1212,7 +1212,7 @@ LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
                                               const char *Name) {
   ErrorUnsupported(E, Name);
   llvm::Type *ElTy = ConvertType(E->getType());
-  llvm::Type *Ty = llvm::PointerType::getUnqual(ElTy);
+  llvm::Type *Ty = UnqualPtrTy;
   return MakeAddrLValue(
       Address(llvm::UndefValue::get(Ty), ElTy, CharUnits::One()), E->getType());
 }
@@ -4599,7 +4599,7 @@ std::optional<LValue> HandleConditionalOperatorLValueSimpleCase(
       if (auto *ThrowExpr = dyn_cast<CXXThrowExpr>(Live->IgnoreParens())) {
         CGF.EmitCXXThrowExpr(ThrowExpr);
         llvm::Type *ElemTy = CGF.ConvertType(Dead->getType());
-        llvm::Type *Ty = llvm::PointerType::getUnqual(ElemTy);
+        llvm::Type *Ty = CGF.UnqualPtrTy;
         return CGF.MakeAddrLValue(
             Address(llvm::UndefValue::get(Ty), ElemTy, CharUnits::One()),
             Dead->getType());

clang/lib/CodeGen/CGObjCRuntime.cpp

@@ -63,12 +63,10 @@ LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
       CGF.CGM.getContext().getObjCObjectPointerType(InterfaceTy);
   QualType IvarTy =
       Ivar->getUsageType(ObjectPtrTy).withCVRQualifiers(CVRQualifiers);
-  llvm::Type *LTy = CGF.CGM.getTypes().ConvertTypeForMem(IvarTy);
-  llvm::Value *V = CGF.Builder.CreateBitCast(BaseValue, CGF.Int8PtrTy);
+  llvm::Value *V = BaseValue;
   V = CGF.Builder.CreateInBoundsGEP(CGF.Int8Ty, V, Offset, "add.ptr");
 
   if (!Ivar->isBitField()) {
-    V = CGF.Builder.CreateBitCast(V, llvm::PointerType::getUnqual(LTy));
     LValue LV = CGF.MakeNaturalAlignAddrLValue(V, IvarTy);
     return LV;
   }

clang/lib/CodeGen/CGOpenCLRuntime.cpp

@@ -71,8 +71,7 @@ llvm::PointerType *CGOpenCLRuntime::getPointerType(const Type *T,
   llvm::LLVMContext &Ctx = CGM.getLLVMContext();
   uint32_t AddrSpc = CGM.getContext().getTargetAddressSpace(
       CGM.getContext().getOpenCLTypeAddrSpace(T));
-  auto *PTy =
-      llvm::PointerType::get(llvm::StructType::create(Ctx, Name), AddrSpc);
+  auto *PTy = llvm::PointerType::get(Ctx, AddrSpc);
   CachedTys[Name] = PTy;
   return PTy;
 }
@@ -90,10 +89,9 @@ llvm::Type *CGOpenCLRuntime::getPipeType(const PipeType *T) {
 llvm::Type *CGOpenCLRuntime::getPipeType(const PipeType *T, StringRef Name,
                                          llvm::Type *&PipeTy) {
   if (!PipeTy)
-    PipeTy = llvm::PointerType::get(llvm::StructType::create(
-      CGM.getLLVMContext(), Name),
-      CGM.getContext().getTargetAddressSpace(
-          CGM.getContext().getOpenCLTypeAddrSpace(T)));
+    PipeTy = llvm::PointerType::get(
+        CGM.getLLVMContext(), CGM.getContext().getTargetAddressSpace(
+                                  CGM.getContext().getOpenCLTypeAddrSpace(T)));
   return PipeTy;
 }
 
@@ -105,10 +103,10 @@ llvm::Type *CGOpenCLRuntime::getSamplerType(const Type *T) {
           CGM, CGM.getContext().OCLSamplerTy.getTypePtr()))
     SamplerTy = TransTy;
   else
+    // struct opencl.sampler_t*
     SamplerTy = llvm::PointerType::get(
-        llvm::StructType::create(CGM.getLLVMContext(), "opencl.sampler_t"),
-        CGM.getContext().getTargetAddressSpace(
-            CGM.getContext().getOpenCLTypeAddrSpace(T)));
+        CGM.getLLVMContext(), CGM.getContext().getTargetAddressSpace(
+                                  CGM.getContext().getOpenCLTypeAddrSpace(T)));
   return SamplerTy;
 }
 

clang/lib/CodeGen/CodeGenModule.cpp

@@ -360,13 +360,14 @@ CodeGenModule::CodeGenModule(ASTContext &C,
   IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth());
   IntPtrTy = llvm::IntegerType::get(LLVMContext,
     C.getTargetInfo().getMaxPointerWidth());
-  Int8PtrTy = Int8Ty->getPointerTo(0);
-  Int8PtrPtrTy = Int8PtrTy->getPointerTo(0);
+  Int8PtrTy = llvm::PointerType::get(LLVMContext, 0);
   const llvm::DataLayout &DL = M.getDataLayout();
-  AllocaInt8PtrTy = Int8Ty->getPointerTo(DL.getAllocaAddrSpace());
-  GlobalsInt8PtrTy = Int8Ty->getPointerTo(DL.getDefaultGlobalsAddressSpace());
-  ConstGlobalsPtrTy = Int8Ty->getPointerTo(
-      C.getTargetAddressSpace(GetGlobalConstantAddressSpace()));
+  AllocaInt8PtrTy =
+      llvm::PointerType::get(LLVMContext, DL.getAllocaAddrSpace());
+  GlobalsInt8PtrTy =
+      llvm::PointerType::get(LLVMContext, DL.getDefaultGlobalsAddressSpace());
+  ConstGlobalsPtrTy = llvm::PointerType::get(
+      LLVMContext, C.getTargetAddressSpace(GetGlobalConstantAddressSpace()));
   ASTAllocaAddressSpace = getTargetCodeGenInfo().getASTAllocaAddressSpace();
 
   // Build C++20 Module initializers.

clang/lib/CodeGen/CodeGenTypeCache.h

@@ -51,14 +51,11 @@ struct CodeGenTypeCache {
     llvm::IntegerType *PtrDiffTy;
   };
 
-  /// void* in address space 0
+  /// void*, void** in address space 0
   union {
+    llvm::PointerType *UnqualPtrTy;
     llvm::PointerType *VoidPtrTy;
     llvm::PointerType *Int8PtrTy;
-  };
-
-  /// void** in address space 0
-  union {
     llvm::PointerType *VoidPtrPtrTy;
     llvm::PointerType *Int8PtrPtrTy;
   };

clang/lib/CodeGen/ItaniumCXXABI.cpp

@@ -750,9 +750,9 @@ CGCallee ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
       } else {
         llvm::Value *VFPAddr =
             CGF.Builder.CreateGEP(CGF.Int8Ty, VTable, VTableOffset);
-        VirtualFn = CGF.Builder.CreateAlignedLoad(
-            llvm::PointerType::getUnqual(CGF.getLLVMContext()), VFPAddr,
-            CGF.getPointerAlign(), "memptr.virtualfn");
+        VirtualFn = CGF.Builder.CreateAlignedLoad(CGF.UnqualPtrTy, VFPAddr,
+                                                  CGF.getPointerAlign(),
+                                                  "memptr.virtualfn");
       }
     }
     assert(VirtualFn && "Virtual fuction pointer not created!");
@@ -792,9 +792,8 @@ CGCallee ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
   // In the non-virtual path, the function pointer is actually a
   // function pointer.
   CGF.EmitBlock(FnNonVirtual);
-  llvm::Value *NonVirtualFn = Builder.CreateIntToPtr(
-      FnAsInt, llvm::PointerType::getUnqual(CGF.getLLVMContext()),
-      "memptr.nonvirtualfn");
+  llvm::Value *NonVirtualFn =
+      Builder.CreateIntToPtr(FnAsInt, CGF.UnqualPtrTy, "memptr.nonvirtualfn");
 
   // Check the function pointer if CFI on member function pointers is enabled.
   if (ShouldEmitCFICheck) {
@@ -833,8 +832,7 @@ CGCallee ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
 
   // We're done.
   CGF.EmitBlock(FnEnd);
-  llvm::PHINode *CalleePtr =
-      Builder.CreatePHI(llvm::PointerType::getUnqual(CGF.getLLVMContext()), 2);
+  llvm::PHINode *CalleePtr = Builder.CreatePHI(CGF.UnqualPtrTy, 2);
   CalleePtr->addIncoming(VirtualFn, FnVirtual);
   CalleePtr->addIncoming(NonVirtualFn, FnNonVirtual);
 
@@ -1238,8 +1236,7 @@ void ItaniumCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
     // Grab the vtable pointer as an intptr_t*.
     auto *ClassDecl =
         cast<CXXRecordDecl>(ElementType->castAs<RecordType>()->getDecl());
-    llvm::Value *VTable = CGF.GetVTablePtr(
-        Ptr, llvm::PointerType::getUnqual(CGF.getLLVMContext()), ClassDecl);
+    llvm::Value *VTable = CGF.GetVTablePtr(Ptr, CGF.UnqualPtrTy, ClassDecl);
 
     // Track back to entry -2 and pull out the offset there.
     llvm::Value *OffsetPtr = CGF.Builder.CreateConstInBoundsGEP1_64(
@@ -1591,9 +1588,8 @@ llvm::Value *ItaniumCXXABI::emitDynamicCastToVoid(CodeGenFunction &CGF,
   llvm::Value *OffsetToTop;
   if (CGM.getItaniumVTableContext().isRelativeLayout()) {
     // Get the vtable pointer.
-    llvm::Value *VTable = CGF.GetVTablePtr(
-        ThisAddr, llvm::PointerType::getUnqual(CGF.getLLVMContext()),
-        ClassDecl);
+    llvm::Value *VTable =
+        CGF.GetVTablePtr(ThisAddr, CGF.UnqualPtrTy, ClassDecl);
 
     // Get the offset-to-top from the vtable.
     OffsetToTop =
@@ -1605,9 +1601,8 @@ llvm::Value *ItaniumCXXABI::emitDynamicCastToVoid(CodeGenFunction &CGF,
         CGF.ConvertType(CGF.getContext().getPointerDiffType());
 
     // Get the vtable pointer.
-    llvm::Value *VTable = CGF.GetVTablePtr(
-        ThisAddr, llvm::PointerType::getUnqual(CGF.getLLVMContext()),
-        ClassDecl);
+    llvm::Value *VTable =
+        CGF.GetVTablePtr(ThisAddr, CGF.UnqualPtrTy, ClassDecl);
 
     // Get the offset-to-top from the vtable.
     OffsetToTop =
@@ -2308,8 +2303,8 @@ llvm::Value *ItaniumCXXABI::readArrayCookieImpl(CodeGenFunction &CGF,
   // cookie, otherwise return 0 to avoid an infinite loop calling DTORs.
   // We can't simply ignore this load using nosanitize metadata because
   // the metadata may be lost.
-  llvm::FunctionType *FTy = llvm::FunctionType::get(
-      CGF.SizeTy, llvm::PointerType::getUnqual(CGF.getLLVMContext()), false);
+  llvm::FunctionType *FTy =
+      llvm::FunctionType::get(CGF.SizeTy, CGF.UnqualPtrTy, false);
   llvm::FunctionCallee F =
       CGM.CreateRuntimeFunction(FTy, "__asan_load_cxx_array_cookie");
   return CGF.Builder.CreateCall(F, numElementsPtr.getPointer());
@@ -2652,7 +2647,7 @@ static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF,
 
   // We're assuming that the destructor function is something we can
   // reasonably call with the default CC.
-  llvm::Type *dtorTy = llvm::PointerType::getUnqual(CGF.getLLVMContext());
+  llvm::Type *dtorTy = CGF.UnqualPtrTy;
 
   // Preserve address space of addr.
   auto AddrAS = addr ? addr->getType()->getPointerAddressSpace() : 0;
@@ -4654,8 +4649,7 @@ static void InitCatchParam(CodeGenFunction &CGF,
   auto catchRD = CatchType->getAsCXXRecordDecl();
   CharUnits caughtExnAlignment = CGF.CGM.getClassPointerAlignment(catchRD);
 
-  llvm::Type *PtrTy =
-      llvm::PointerType::getUnqual(CGF.getLLVMContext()); // addrspace 0 ok
+  llvm::Type *PtrTy = CGF.UnqualPtrTy; // addrspace 0 ok
 
   // Check for a copy expression.  If we don't have a copy expression,
   // that means a trivial copy is okay.
@@ -4843,8 +4837,7 @@ void XLCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
                                   llvm::FunctionCallee Dtor,
                                   llvm::Constant *Addr) {
   if (D.getTLSKind() != VarDecl::TLS_None) {
-    llvm::PointerType *PtrTy =
-        llvm::PointerType::getUnqual(CGF.getLLVMContext());
+    llvm::PointerType *PtrTy = CGF.UnqualPtrTy;
 
     // extern "C" int __pt_atexit_np(int flags, int(*)(int,...), ...);
     llvm::FunctionType *AtExitTy =

clang/lib/CodeGen/Targets/PPC.cpp

@@ -431,7 +431,7 @@ Address PPC32_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAList,
 
   llvm::Type *DirectTy = CGF.ConvertType(Ty), *ElementTy = DirectTy;
   if (isIndirect)
-    DirectTy = llvm::PointerType::getUnqual(CGF.getLLVMContext());
+    DirectTy = CGF.UnqualPtrTy;
 
   // Case 1: consume registers.
   Address RegAddr = Address::invalid();

clang/lib/CodeGen/Targets/Sparc.cpp

@@ -286,7 +286,7 @@ Address SparcV9ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
   CGBuilderTy &Builder = CGF.Builder;
   Address Addr = Address(Builder.CreateLoad(VAListAddr, "ap.cur"),
                          getVAListElementType(CGF), SlotSize);
-  llvm::Type *ArgPtrTy = llvm::PointerType::getUnqual(ArgTy);
+  llvm::Type *ArgPtrTy = CGF.UnqualPtrTy;
 
   auto TypeInfo = getContext().getTypeInfoInChars(Ty);
 

clang/lib/CodeGen/Targets/X86.cpp

@@ -2978,9 +2978,7 @@ static Address EmitX86_64VAArgFromMemory(CodeGenFunction &CGF,
 
   // AMD64-ABI 3.5.7p5: Step 8. Fetch type from l->overflow_arg_area.
   llvm::Type *LTy = CGF.ConvertTypeForMem(Ty);
-  llvm::Value *Res =
-    CGF.Builder.CreateBitCast(overflow_arg_area,
-                              llvm::PointerType::getUnqual(LTy));
+  llvm::Value *Res = overflow_arg_area;
 
   // AMD64-ABI 3.5.7p5: Step 9. Set l->overflow_arg_area to:
   // l->overflow_arg_area + sizeof(type).
@@ -3083,8 +3081,6 @@ Address X86_64ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
     llvm::Type *TyHi = ST->getElementType(1);
     assert((TyLo->isFPOrFPVectorTy() ^ TyHi->isFPOrFPVectorTy()) &&
            "Unexpected ABI info for mixed regs");
-    llvm::Type *PTyLo = llvm::PointerType::getUnqual(TyLo);
-    llvm::Type *PTyHi = llvm::PointerType::getUnqual(TyHi);
     llvm::Value *GPAddr =
         CGF.Builder.CreateGEP(CGF.Int8Ty, RegSaveArea, gp_offset);
     llvm::Value *FPAddr =
@@ -3095,13 +3091,13 @@ Address X86_64ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
     // Copy the first element.
     // FIXME: Our choice of alignment here and below is probably pessimistic.
     llvm::Value *V = CGF.Builder.CreateAlignedLoad(
-        TyLo, CGF.Builder.CreateBitCast(RegLoAddr, PTyLo),
+        TyLo, RegLoAddr,
         CharUnits::fromQuantity(getDataLayout().getABITypeAlign(TyLo)));
     CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 0));
 
     // Copy the second element.
     V = CGF.Builder.CreateAlignedLoad(
-        TyHi, CGF.Builder.CreateBitCast(RegHiAddr, PTyHi),
+        TyHi, RegHiAddr,
         CharUnits::fromQuantity(getDataLayout().getABITypeAlign(TyHi)));
     CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 1));