[CodeGen][arm64e] Add methods and data members to Address, which are needed to authenticate signed pointers (#86721)

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.

This reapplies 8bd1f9116aab879183f34707e6d21c7051d083b6. The commit
broke msan bots because LValue::IsKnownNonNull was uninitialized.

1 files changed, 11 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index 5a9d06d..34f2893 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -397,7 +397,7 @@ namespace {
 void CodeGenFunction::EmitAnyExprToExn(const Expr *e, Address addr) {
   // Make sure the exception object is cleaned up if there's an
   // exception during initialization.
-  pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
+  pushFullExprCleanup<FreeException>(EHCleanup, addr.emitRawPointer(*this));
   EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
 
   // __cxa_allocate_exception returns a void*;  we need to cast this
@@ -416,8 +416,8 @@ void CodeGenFunction::EmitAnyExprToExn(const Expr *e, Address addr) {
                    /*IsInit*/ true);
 
   // Deactivate the cleanup block.
-  DeactivateCleanupBlock(cleanup,
-                         cast<llvm::Instruction>(typedAddr.getPointer()));
+  DeactivateCleanupBlock(
+      cleanup, cast<llvm::Instruction>(typedAddr.emitRawPointer(*this)));
 }
 
 Address CodeGenFunction::getExceptionSlot() {
@@ -1834,7 +1834,8 @@ Address CodeGenFunction::recoverAddrOfEscapedLocal(CodeGenFunction &ParentCGF,
                                                    llvm::Value *ParentFP) {
   llvm::CallInst *RecoverCall = nullptr;
   CGBuilderTy Builder(*this, AllocaInsertPt);
-  if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
+  if (auto *ParentAlloca =
+          dyn_cast_or_null<llvm::AllocaInst>(ParentVar.getBasePointer())) {
     // Mark the variable escaped if nobody else referenced it and compute the
     // localescape index.
     auto InsertPair = ParentCGF.EscapedLocals.insert(
@@ -1851,8 +1852,8 @@ Address CodeGenFunction::recoverAddrOfEscapedLocal(CodeGenFunction &ParentCGF,
     // If the parent didn't have an alloca, we're doing some nested outlining.
     // Just clone the existing localrecover call, but tweak the FP argument to
     // use our FP value. All other arguments are constants.
-    auto *ParentRecover =
-        cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
+    auto *ParentRecover = cast<llvm::IntrinsicInst>(
+        ParentVar.emitRawPointer(*this)->stripPointerCasts());
     assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
            "expected alloca or localrecover in parent LocalDeclMap");
     RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
@@ -1925,7 +1926,8 @@ void CodeGenFunction::EmitCapturedLocals(CodeGenFunction &ParentCGF,
         if (isa<ImplicitParamDecl>(D) &&
             D->getType() == getContext().VoidPtrTy) {
           assert(D->getName().starts_with("frame_pointer"));
-          FramePtrAddrAlloca = cast<llvm::AllocaInst>(I.second.getPointer());
+          FramePtrAddrAlloca =
+              cast<llvm::AllocaInst>(I.second.getBasePointer());
           break;
         }
       }
@@ -1986,7 +1988,8 @@ void CodeGenFunction::EmitCapturedLocals(CodeGenFunction &ParentCGF,
         LValue ThisFieldLValue =
             EmitLValueForLambdaField(LambdaThisCaptureField);
         if (!LambdaThisCaptureField->getType()->isPointerType()) {
-          CXXThisValue = ThisFieldLValue.getAddress(*this).getPointer();
+          CXXThisValue =
+              ThisFieldLValue.getAddress(*this).emitRawPointer(*this);
         } else {
           CXXThisValue = EmitLoadOfLValue(ThisFieldLValue, SourceLocation())
                              .getScalarVal();