[clang] [Arm64EC][clang] Implement varargs support in clang. (PR #152411)

[Daniel Paoliello via cfe-commits]

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@@ -132,6 +132,10 @@ class ABIInfo {
   virtual llvm::FixedVectorType *
   getOptimalVectorMemoryType(llvm::FixedVectorType *T,
                              const LangOptions &Opt) const;
+
+  /// Used by Arm64EC calling convention code to call into x86 calling
+  /// convention code for varargs function.
+  virtual ABIArgInfo classifyArgForArm64ECVarArg(QualType Ty) const;
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dpaoliello wrote:

Ah, ok, didn't notice the lack of a declaration in any header files.

https://github.com/llvm/llvm-project/pull/152411