[lumen] Lower gc and gc-leaf-function function attributes

Author: bitwalker

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

@@ -787,6 +787,7 @@ def LLVM_LLVMFuncOp
       Arguments<(ins DefaultValuedAttr<Linkage,
                                        "Linkage::External">:$linkage,
                      OptionalAttr<FlatSymbolRefAttr>:$personality,
+                     OptionalAttr<StrAttr>:$gc,
                      OptionalAttr<ArrayAttr>:$passthrough)> {
   let summary = "LLVM dialect function, has wrapped LLVM IR function type";
 

mlir/lib/Target/LLVMIR/ModuleTranslation.cpp

@@ -940,6 +940,15 @@ LogicalResult ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
       llvmFunc->setPersonalityFn(pfunc);
   }
 
+  // Check the gc strategy and set it
+  auto gcStrategy = func.gc();
+  if (gcStrategy.hasValue()) {
+    llvmFunc->setGC(gcStrategy.getValue().str());
+  }
+  auto gcLeafAttr = func.getAttrOfType<BoolAttr>("gc-leaf-function");
+  if (gcLeafAttr && gcLeafAttr.getValue())
+      llvmFunc->addFnAttr("gc-leaf-function", "1");
+
   // First, create all blocks so we can jump to them; (in topological order 
   // to ensure defs are converted before uses)
   auto blocks = topologicalSort(func);