[CodeGen][arm64e] Add methods and data members to Address, which are needed to authenticate signed pointers (#67454)

To authenticate pointers, CodeGen needs access to the key and
discriminators that were used to sign the pointer. That information is
sometimes known from the context, but not always, which is why `Address`
needs to hold that information.

This patch adds methods and data members to `Address`, which will be
needed in subsequent patches to authenticate signed pointers, and uses
the newly added methods throughout CodeGen. Although this patch isn't
strictly NFC as it causes CodeGen to use different code paths in some
cases (e.g., `mergeAddressesInConditionalExpr`), it doesn't cause any
changes in functionality as it doesn't add any information needed for
authentication.

In addition to the changes mentioned above, this patch introduces class
`RawAddress`, which contains a pointer that we know is unsigned, and
adds several new functions for creating `Address` and `LValue` objects.

1 files changed, 42 insertions, 29 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index fad26c4..0ceac7d 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -193,26 +193,35 @@ CodeGenFunction::CGFPOptionsRAII::~CGFPOptionsRAII() {
   CGF.Builder.setDefaultConstrainedRounding(OldRounding);
 }
 
-LValue CodeGenFunction::MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T) {
+static LValue MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T,
+                                         bool ForPointeeType,
+                                         CodeGenFunction &CGF) {
   LValueBaseInfo BaseInfo;
   TBAAAccessInfo TBAAInfo;
-  CharUnits Alignment = CGM.getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo);
-  Address Addr(V, ConvertTypeForMem(T), Alignment);
-  return LValue::MakeAddr(Addr, T, getContext(), BaseInfo, TBAAInfo);
+  CharUnits Alignment =
+      CGF.CGM.getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo, ForPointeeType);
+  Address Addr = Address(V, CGF.ConvertTypeForMem(T), Alignment);
+  return CGF.MakeAddrLValue(Addr, T, BaseInfo, TBAAInfo);
+}
+
+LValue CodeGenFunction::MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T) {
+  return ::MakeNaturalAlignAddrLValue(V, T, /*ForPointeeType*/ false, *this);
 }
 
-/// Given a value of type T* that may not be to a complete object,
-/// construct an l-value with the natural pointee alignment of T.
 LValue
 CodeGenFunction::MakeNaturalAlignPointeeAddrLValue(llvm::Value *V, QualType T) {
-  LValueBaseInfo BaseInfo;
-  TBAAAccessInfo TBAAInfo;
-  CharUnits Align = CGM.getNaturalTypeAlignment(T, &BaseInfo, &TBAAInfo,
-                                                /* forPointeeType= */ true);
-  Address Addr(V, ConvertTypeForMem(T), Align);
-  return MakeAddrLValue(Addr, T, BaseInfo, TBAAInfo);
+  return ::MakeNaturalAlignAddrLValue(V, T, /*ForPointeeType*/ true, *this);
+}
+
+LValue CodeGenFunction::MakeNaturalAlignRawAddrLValue(llvm::Value *V,
+                                                      QualType T) {
+  return ::MakeNaturalAlignAddrLValue(V, T, /*ForPointeeType*/ false, *this);
 }
 
+LValue CodeGenFunction::MakeNaturalAlignPointeeRawAddrLValue(llvm::Value *V,
+                                                             QualType T) {
+  return ::MakeNaturalAlignAddrLValue(V, T, /*ForPointeeType*/ true, *this);
+}
 
 llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) {
   return CGM.getTypes().ConvertTypeForMem(T);
@@ -525,7 +534,8 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
     ReturnBlock.getBlock()->eraseFromParent();
   }
   if (ReturnValue.isValid()) {
-    auto *RetAlloca = dyn_cast<llvm::AllocaInst>(ReturnValue.getPointer());
+    auto *RetAlloca =
+        dyn_cast<llvm::AllocaInst>(ReturnValue.emitRawPointer(*this));
     if (RetAlloca && RetAlloca->use_empty()) {
       RetAlloca->eraseFromParent();
       ReturnValue = Address::invalid();
@@ -1122,13 +1132,14 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
     auto AI = CurFn->arg_begin();
     if (CurFnInfo->getReturnInfo().isSRetAfterThis())
       ++AI;
-    ReturnValue =
-        Address(&*AI, ConvertType(RetTy),
-                CurFnInfo->getReturnInfo().getIndirectAlign(), KnownNonNull);
+    ReturnValue = makeNaturalAddressForPointer(
+        &*AI, RetTy, CurFnInfo->getReturnInfo().getIndirectAlign(), false,
+        nullptr, nullptr, KnownNonNull);
     if (!CurFnInfo->getReturnInfo().getIndirectByVal()) {
-      ReturnValuePointer = CreateDefaultAlignTempAlloca(
-          ReturnValue.getPointer()->getType(), "result.ptr");
-      Builder.CreateStore(ReturnValue.getPointer(), ReturnValuePointer);
+      ReturnValuePointer =
+          CreateDefaultAlignTempAlloca(ReturnValue.getType(), "result.ptr");
+      Builder.CreateStore(ReturnValue.emitRawPointer(*this),
+                          ReturnValuePointer);
     }
   } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca &&
              !hasScalarEvaluationKind(CurFnInfo->getReturnType())) {
@@ -1189,8 +1200,9 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
         // or contains the address of the enclosing object).
         LValue ThisFieldLValue = EmitLValueForLambdaField(LambdaThisCaptureField);
         if (!LambdaThisCaptureField->getType()->isPointerType()) {
-          // If the enclosing object was captured by value, just use its address.
-          CXXThisValue = ThisFieldLValue.getAddress(*this).getPointer();
+          // If the enclosing object was captured by value, just use its
+          // address. Sign this pointer.
+          CXXThisValue = ThisFieldLValue.getPointer(*this);
         } else {
           // Load the lvalue pointed to by the field, since '*this' was captured
           // by reference.
@@ -2012,8 +2024,9 @@ static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType,
     = llvm::ConstantInt::get(CGF.IntPtrTy, baseSize.getQuantity());
 
   Address begin = dest.withElementType(CGF.Int8Ty);
-  llvm::Value *end = Builder.CreateInBoundsGEP(
-      begin.getElementType(), begin.getPointer(), sizeInChars, "vla.end");
+  llvm::Value *end = Builder.CreateInBoundsGEP(begin.getElementType(),
+                                               begin.emitRawPointer(CGF),
+                                               sizeInChars, "vla.end");
 
   llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock();
   llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop");
@@ -2024,7 +2037,7 @@ static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType,
   CGF.EmitBlock(loopBB);
 
   llvm::PHINode *cur = Builder.CreatePHI(begin.getType(), 2, "vla.cur");
-  cur->addIncoming(begin.getPointer(), originBB);
+  cur->addIncoming(begin.emitRawPointer(CGF), originBB);
 
   CharUnits curAlign =
     dest.getAlignment().alignmentOfArrayElement(baseSize);
@@ -2218,10 +2231,10 @@ llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType,
     addr = addr.withElementType(baseType);
   } else {
     // Create the actual GEP.
-    addr = Address(Builder.CreateInBoundsGEP(
-        addr.getElementType(), addr.getPointer(), gepIndices, "array.begin"),
-        ConvertTypeForMem(eltType),
-        addr.getAlignment());
+    addr = Address(Builder.CreateInBoundsGEP(addr.getElementType(),
+                                             addr.emitRawPointer(*this),
+                                             gepIndices, "array.begin"),
+                   ConvertTypeForMem(eltType), addr.getAlignment());
   }
 
   baseType = eltType;
@@ -2562,7 +2575,7 @@ void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) {
 Address CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D,
                                               Address Addr) {
   assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
-  llvm::Value *V = Addr.getPointer();
+  llvm::Value *V = Addr.emitRawPointer(*this);
   llvm::Type *VTy = V->getType();
   auto *PTy = dyn_cast<llvm::PointerType>(VTy);
   unsigned AS = PTy ? PTy->getAddressSpace() : 0;