[clang] [CIR] Add calling_conv attribute to FuncOp with lowering support (PR #189345)

[Rana Pratap Reddy via cfe-commits]

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@@ -182,6 +182,27 @@ mlir::LLVM::Linkage convertLinkage(cir::GlobalLinkageKind linkage) {
   llvm_unreachable("Unknown CIR linkage type");
 }
 
+static mlir::LLVM::CConv convertCallingConv(cir::CallingConv callingConv) {
+  using CIR = cir::CallingConv;
+  using LLVM = mlir::LLVM::CConv;
+
+  switch (callingConv) {
+  case CIR::C:
+    return LLVM::C;
+  case CIR::SpirKernel:
+    return LLVM::SPIR_KERNEL;
+  case CIR::SpirFunction:
+    return LLVM::SPIR_FUNC;
+  case CIR::OpenCLKernel:
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ranapratap55 wrote:

 Replaced with an assert for OpenCLKernel.

https://github.com/llvm/llvm-project/pull/189345