[clang] [PAC] Add support for __ptrauth type qualifier (PR #100830)

[Akira Hatanaka via cfe-commits]

================
@@ -2249,6 +2249,53 @@ Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
   return V;
 }
 
+static bool isDeclRefKnownNonNull(CodeGenFunction &CGF, const ValueDecl *D) {
+  return !D->isWeak();
+}
+
+static bool isLValueKnownNonNull(CodeGenFunction &CGF, const Expr *E) {
+  E = E->IgnoreParens();
+
+  if (const auto *UO = dyn_cast<UnaryOperator>(E))
+    if (UO->getOpcode() == UO_Deref)
+      return CGF.isPointerKnownNonNull(UO->getSubExpr());
+
+  if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
+    return isDeclRefKnownNonNull(CGF, DRE->getDecl());
+
+  if (const auto *ME = dyn_cast<MemberExpr>(E)) {
+    if (isa<FieldDecl>(ME->getMemberDecl()))
+      return true;
+    return isDeclRefKnownNonNull(CGF, ME->getMemberDecl());
+  }
+
+  // Array subscripts?  Anything else?
+
+  return false;
+}
+
+bool CodeGenFunction::isPointerKnownNonNull(const Expr *E) {
+  assert(E->getType()->isSignableType());
+
+  E = E->IgnoreParens();
+
+  if (isa<CXXThisExpr>(E))
+    return true;
+
+  if (const auto *UO = dyn_cast<UnaryOperator>(E))
+    if (UO->getOpcode() == UO_AddrOf)
+      return isLValueKnownNonNull(*this, UO->getSubExpr());
+
+  if (const auto *CE = dyn_cast<CastExpr>(E))
+    if (CE->getCastKind() == CK_FunctionToPointerDecay ||
+        CE->getCastKind() == CK_ArrayToPointerDecay)
+      return isLValueKnownNonNull(*this, CE->getSubExpr());
+
+  // Maybe honor __nonnull?
----------------
ahatanak wrote:

I will file an issue after this PR is merged.

https://github.com/llvm/llvm-project/pull/100830