[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, 4 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 8dee3f7..862369a 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -201,14 +201,13 @@ CodeGenFunction::GenerateVarArgsThunk(llvm::Function *Fn,
 
   // Find the first store of "this", which will be to the alloca associated
   // with "this".
-  Address ThisPtr =
-      Address(&*AI, ConvertTypeForMem(MD->getFunctionObjectParameterType()),
-              CGM.getClassPointerAlignment(MD->getParent()));
+  Address ThisPtr = makeNaturalAddressForPointer(
+      &*AI, MD->getFunctionObjectParameterType(),
+      CGM.getClassPointerAlignment(MD->getParent()));
   llvm::BasicBlock *EntryBB = &Fn->front();
   llvm::BasicBlock::iterator ThisStore =
       llvm::find_if(*EntryBB, [&](llvm::Instruction &I) {
-        return isa<llvm::StoreInst>(I) &&
-               I.getOperand(0) == ThisPtr.getPointer();
+        return isa<llvm::StoreInst>(I) && I.getOperand(0) == &*AI;
       });
   assert(ThisStore != EntryBB->end() &&
          "Store of this should be in entry block?");