[Clang][AArch64] Add diagnostics for builtins that use ZT0. (#79140)

Similar to what we did for ZA, this patch adds diagnostics to flag when
using a ZT0 builtin in a function that does not have ZT0 state.

1 files changed, 17 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 1f83dcf..7833d5a 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3013,6 +3013,11 @@ enum ArmSMEState : unsigned {
   ArmOutZA = 0b10,
   ArmInOutZA = 0b11,
   ArmZAMask = 0b11,
+
+  ArmInZT0 = 0b01 << 2,
+  ArmOutZT0 = 0b10 << 2,
+  ArmInOutZT0 = 0b11 << 2,
+  ArmZT0Mask = 0b11 << 2
 };
 
 bool Sema::ParseSVEImmChecks(
@@ -3206,6 +3211,13 @@ static bool hasArmZAState(const FunctionDecl *FD) {
          (FD->hasAttr<ArmNewAttr>() && FD->getAttr<ArmNewAttr>()->isNewZA());
 }
 
+static bool hasArmZT0State(const FunctionDecl *FD) {
+  const auto *T = FD->getType()->getAs<FunctionProtoType>();
+  return (T && FunctionType::getArmZT0State(T->getAArch64SMEAttributes()) !=
+                   FunctionType::ARM_None) ||
+         (FD->hasAttr<ArmNewAttr>() && FD->getAttr<ArmNewAttr>()->isNewZT0());
+}
+
 static ArmSMEState getSMEState(unsigned BuiltinID) {
   switch (BuiltinID) {
   default:
@@ -3233,6 +3245,11 @@ bool Sema::CheckSMEBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
       Diag(TheCall->getBeginLoc(),
            diag::warn_attribute_arm_za_builtin_no_za_state)
           << TheCall->getSourceRange();
+
+    if ((getSMEState(BuiltinID) & ArmZT0Mask) && !hasArmZT0State(FD))
+      Diag(TheCall->getBeginLoc(),
+           diag::warn_attribute_arm_zt0_builtin_no_zt0_state)
+          << TheCall->getSourceRange();
   }
 
   // Range check SME intrinsics that take immediate values.