[Clang] Amend SME attributes with support for ZT0. (#77941)

This patch builds on top of #76971 and implements support for:
* __arm_new("zt0")
* __arm_in("zt0")
* __arm_out("zt0")
* __arm_inout("zt0")
* __arm_preserves("zt0")

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 13ca438..f9bf1d1 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -12234,12 +12234,15 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
     const auto *Attr = NewFD->getAttr<ArmNewAttr>();
     bool UsesSM = NewFD->hasAttr<ArmLocallyStreamingAttr>();
     bool UsesZA = Attr && Attr->isNewZA();
+    bool UsesZT0 = Attr && Attr->isNewZT0();
     if (const auto *FPT = NewFD->getType()->getAs<FunctionProtoType>()) {
       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
       UsesSM |=
           EPI.AArch64SMEAttributes & FunctionType::SME_PStateSMEnabledMask;
       UsesZA |= FunctionType::getArmZAState(EPI.AArch64SMEAttributes) !=
                 FunctionType::ARM_None;
+      UsesZT0 |= FunctionType::getArmZT0State(EPI.AArch64SMEAttributes) !=
+                 FunctionType::ARM_None;
     }
 
     if (UsesSM || UsesZA) {
@@ -12254,6 +12257,14 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
                diag::err_sme_definition_using_za_in_non_sme_target);
       }
     }
+    if (UsesZT0) {
+      llvm::StringMap<bool> FeatureMap;
+      Context.getFunctionFeatureMap(FeatureMap, NewFD);
+      if (!FeatureMap.contains("sme2")) {
+        Diag(NewFD->getLocation(),
+             diag::err_sme_definition_using_zt0_in_non_sme2_target);
+      }
+    }
   }
 
   return Redeclaration;