[clang] [CIR] Support reference type of non-record ptr in InitCatchParam (PR #195722)

[Andy Kaylor via cfe-commits]

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@@ -621,18 +622,35 @@ ItaniumEHLowering::resolveCatchCopyThunk(cir::ConstructCatchParamOp op) {
 mlir::LogicalResult
 ItaniumEHLowering::lowerConstructCatchParam(cir::ConstructCatchParamOp op,
                                             mlir::Value exnPtr) {
+  mlir::Location loc = op.getLoc();
+  mlir::Value paramAddr = op.getParamAddr();
+  cir::PointerType paramAddrType =
+      mlir::cast<cir::PointerType>(paramAddr.getType());
+
+  if (op.getKind() == cir::InitCatchKind::Reference) {
+    assert(!MissingFeatures::winSizeOfUnwindException());
+    constexpr unsigned headerSize = 32;
+
+    builder.setInsertionPoint(op);
+    auto index = cir::ConstantOp::create(
+        builder, loc, cir::IntAttr::get(u32Type, headerSize));
+    auto exnObj =
+        cir::PtrStrideOp::create(builder, loc, exnPtr.getType(), exnPtr, index);
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andykaylor wrote:

Is `exnPtr.getType` here guaranteed to be `void*` or `i8*`? Maybe add an assertion, because this PtrStrideOp will be incorrect otherwise.

https://github.com/llvm/llvm-project/pull/195722