[clang] [SystemZ][z/OS] Implement z/OS XPLINK ABI (PR #91384)

[Kai Nacke via cfe-commits]

================
@@ -529,9 +529,324 @@ bool SystemZTargetCodeGenInfo::isVectorTypeBased(const Type *Ty,
   return false;
 }
 
+//===----------------------------------------------------------------------===//
+// z/OS XPLINK ABI Implementation
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+class ZOSXPLinkABIInfo : public ABIInfo {
+  static const unsigned GPRBits = 64;
+  bool HasVector;
+
+public:
+  ZOSXPLinkABIInfo(CodeGenTypes &CGT, bool HV) : ABIInfo(CGT), HasVector(HV) {}
+
+  bool isPromotableIntegerType(QualType Ty) const;
+  bool isCompoundType(QualType Ty) const;
+  bool isVectorArgumentType(QualType Ty) const;
+  bool isFPArgumentType(QualType Ty) const;
+  QualType GetSingleElementType(QualType Ty) const;
+  bool IsLikeComplexType(QualType Ty) const;
----------------
redstar wrote:

Coding convention:
```suggestion
  bool isLikeComplexType(QualType Ty) const;
```

https://github.com/llvm/llvm-project/pull/91384