RTTI: refactor the uniqueness question into CGCXXABI.

This also brings the code into closer conformance with usual LLVM
coding style and other surrounding conventions.

llvm-svn: 205158

1 files changed, 30 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGCXXABI.h b/clang/lib/CodeGen/CGCXXABI.h
index 783cc594361..beaec2c2217 100644
--- a/clang/lib/CodeGen/CGCXXABI.h
+++ b/clang/lib/CodeGen/CGCXXABI.h
@@ -484,6 +484,36 @@ public:
   virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
                                               const VarDecl *VD,
                                               QualType LValType);
+
+  /**************************** RTTI Uniqueness ******************************/
+
+protected:
+  /// Returns true if the ABI requires RTTI type_info objects to be unique
+  /// across a program.
+  virtual bool shouldRTTIBeUnique() { return true; }
+
+public:
+  /// What sort of unique-RTTI behavior should we use?
+  enum RTTIUniquenessKind {
+    /// We are guaranteeing, or need to guarantee, that the RTTI string
+    /// is unique.
+    RUK_Unique,
+
+    /// We are not guaranteeing uniqueness for the RTTI string, so we
+    /// can demote to hidden visibility but must use string comparisons.
+    RUK_NonUniqueHidden,
+
+    /// We are not guaranteeing uniqueness for the RTTI string, so we
+    /// have to use string comparisons, but we also have to emit it with
+    /// non-hidden visibility.
+    RUK_NonUniqueVisible
+  };
+
+  /// Return the required visibility status for the given type and linkage in
+  /// the current ABI.
+  RTTIUniquenessKind
+  classifyRTTIUniqueness(QualType CanTy,
+                         llvm::GlobalValue::LinkageTypes Linkage);
 };
 
 // Create an instance of a C++ ABI class: