[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, 16 insertions, 12 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 2ef5ed0..267f2e4 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1461,7 +1461,7 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
   bool EmitDebugInfo = DI && CGM.getCodeGenOpts().hasReducedDebugInfo();
 
   Address address = Address::invalid();
-  Address AllocaAddr = Address::invalid();
+  RawAddress AllocaAddr = RawAddress::invalid();
   Address OpenMPLocalAddr = Address::invalid();
   if (CGM.getLangOpts().OpenMPIRBuilder)
     OpenMPLocalAddr = OMPBuilderCBHelpers::getAddressOfLocalVariable(*this, &D);
@@ -1524,7 +1524,10 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
       // return slot, so that we can elide the copy when returning this
       // variable (C++0x [class.copy]p34).
       address = ReturnValue;
-      AllocaAddr = ReturnValue;
+      AllocaAddr =
+          RawAddress(ReturnValue.emitRawPointer(*this),
+                     ReturnValue.getElementType(), ReturnValue.getAlignment());
+      ;
 
       if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
         const auto *RD = RecordTy->getDecl();
@@ -1535,7 +1538,7 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
           // to this variable. Set it to zero to indicate that NRVO was not
           // applied.
           llvm::Value *Zero = Builder.getFalse();
-          Address NRVOFlag =
+          RawAddress NRVOFlag =
               CreateTempAlloca(Zero->getType(), CharUnits::One(), "nrvo");
           EnsureInsertPoint();
           Builder.CreateStore(Zero, NRVOFlag);
@@ -1678,7 +1681,7 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
   }
 
   if (D.hasAttr<AnnotateAttr>() && HaveInsertPoint())
-    EmitVarAnnotations(&D, address.getPointer());
+    EmitVarAnnotations(&D, address.emitRawPointer(*this));
 
   // Make sure we call @llvm.lifetime.end.
   if (emission.useLifetimeMarkers())
@@ -1851,12 +1854,13 @@ void CodeGenFunction::emitZeroOrPatternForAutoVarInit(QualType type,
     llvm::Value *BaseSizeInChars =
         llvm::ConstantInt::get(IntPtrTy, EltSize.getQuantity());
     Address Begin = Loc.withElementType(Int8Ty);
-    llvm::Value *End = Builder.CreateInBoundsGEP(
-        Begin.getElementType(), Begin.getPointer(), SizeVal, "vla.end");
+    llvm::Value *End = Builder.CreateInBoundsGEP(Begin.getElementType(),
+                                                 Begin.emitRawPointer(*this),
+                                                 SizeVal, "vla.end");
     llvm::BasicBlock *OriginBB = Builder.GetInsertBlock();
     EmitBlock(LoopBB);
     llvm::PHINode *Cur = Builder.CreatePHI(Begin.getType(), 2, "vla.cur");
-    Cur->addIncoming(Begin.getPointer(), OriginBB);
+    Cur->addIncoming(Begin.emitRawPointer(*this), OriginBB);
     CharUnits CurAlign = Loc.getAlignment().alignmentOfArrayElement(EltSize);
     auto *I =
         Builder.CreateMemCpy(Address(Cur, Int8Ty, CurAlign),
@@ -2283,7 +2287,7 @@ void CodeGenFunction::emitDestroy(Address addr, QualType type,
     checkZeroLength = false;
   }
 
-  llvm::Value *begin = addr.getPointer();
+  llvm::Value *begin = addr.emitRawPointer(*this);
   llvm::Value *end =
       Builder.CreateInBoundsGEP(addr.getElementType(), begin, length);
   emitArrayDestroy(begin, end, type, elementAlign, destroyer,
@@ -2543,7 +2547,7 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg,
   }
 
   Address DeclPtr = Address::invalid();
-  Address AllocaPtr = Address::invalid();
+  RawAddress AllocaPtr = Address::invalid();
   bool DoStore = false;
   bool IsScalar = hasScalarEvaluationKind(Ty);
   bool UseIndirectDebugAddress = false;
@@ -2555,8 +2559,8 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg,
     // Indirect argument is in alloca address space, which may be different
     // from the default address space.
     auto AllocaAS = CGM.getASTAllocaAddressSpace();
-    auto *V = DeclPtr.getPointer();
-    AllocaPtr = DeclPtr;
+    auto *V = DeclPtr.emitRawPointer(*this);
+    AllocaPtr = RawAddress(V, DeclPtr.getElementType(), DeclPtr.getAlignment());
 
     // For truly ABI indirect arguments -- those that are not `byval` -- store
     // the address of the argument on the stack to preserve debug information.
@@ -2695,7 +2699,7 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg,
   }
 
   if (D.hasAttr<AnnotateAttr>())
-    EmitVarAnnotations(&D, DeclPtr.getPointer());
+    EmitVarAnnotations(&D, DeclPtr.emitRawPointer(*this));
 
   // We can only check return value nullability if all arguments to the
   // function satisfy their nullability preconditions. This makes it necessary