[clang] [AArch64][PAC] Support ptrauth builtins and -fptrauth-intrinsics. (PR #65996)

[Anatoly Trosinenko via cfe-commits]

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@@ -1908,6 +1908,176 @@ static bool SemaOpenCLBuiltinToAddr(Sema &S, unsigned BuiltinID,
   return false;
 }
 
+namespace {
+  enum PointerAuthOpKind {
+    PAO_Strip, PAO_Sign, PAO_Auth, PAO_SignGeneric, PAO_Discriminator,
+    PAO_BlendPointer, PAO_BlendInteger
+  };
+}
+
+static bool checkPointerAuthEnabled(Sema &S, Expr *E) {
+  if (S.getLangOpts().PointerAuthIntrinsics)
+    return false;
+
+  S.Diag(E->getExprLoc(), diag::err_ptrauth_disabled) << E->getSourceRange();
+  return true;
+}
+
+static bool checkPointerAuthKey(Sema &S, Expr *&Arg) {
+  // Convert it to type 'int'.
+  if (convertArgumentToType(S, Arg, S.Context.IntTy))
+    return true;
+
+  // Value-dependent expressions are okay; wait for template instantiation.
+  if (Arg->isValueDependent())
+    return false;
+
+  unsigned KeyValue;
+  return S.checkConstantPointerAuthKey(Arg, KeyValue);
+}
+
+bool Sema::checkConstantPointerAuthKey(Expr *Arg, unsigned &Result) {
+  // Attempt to constant-evaluate the expression.
+  std::optional<llvm::APSInt> KeyValue = Arg->getIntegerConstantExpr(Context);
+  if (!KeyValue) {
+    Diag(Arg->getExprLoc(), diag::err_expr_not_ice) << 0
+      << Arg->getSourceRange();
+    return true;
+  }
+
+  // Ask the target to validate the key parameter.
+  if (!Context.getTargetInfo().validatePointerAuthKey(*KeyValue)) {
+    llvm::SmallString<32> Value; {
+      llvm::raw_svector_ostream Str(Value);
+      Str << *KeyValue;
+    }
+
+    Diag(Arg->getExprLoc(), diag::err_ptrauth_invalid_key)
+      << Value << Arg->getSourceRange();
+    return true;
+  }
+
+  Result = KeyValue->getZExtValue();
+  return false;
+}
+
+static bool checkPointerAuthValue(Sema &S, Expr *&Arg,
+                                  PointerAuthOpKind OpKind) {
+  if (Arg->hasPlaceholderType()) {
+    ExprResult R = S.CheckPlaceholderExpr(Arg);
+    if (R.isInvalid()) return true;
+    Arg = R.get();
+  }
+
+  auto allowsPointer = [](PointerAuthOpKind OpKind) {
+    return OpKind != PAO_BlendInteger;
+  };
+  auto allowsInteger = [](PointerAuthOpKind OpKind) {
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atrosinenko wrote:

Local variable name starts with lower case.

https://github.com/llvm/llvm-project/pull/65996