[CIR] ThrowOp with Complex type as Subexpr (llvm#163078)

Upstream support to throw Complex type with RTTI and update
`getComdatAttr` to perform symtab lookup before adding new selector to
comdat, to avoid generating duplicate symbol in comdat.

Ref from FIR:
https://github.com/llvm/clangir/blob/8c0951a3efbc6fec04312d36739771b2c840c8d2/flang/lib/Optimizer/CodeGen/CodeGen.cpp#L3281-L3283

Issue llvm#154992

Author: AmrDeveloper

clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp

@@ -939,8 +939,7 @@ const char *vTableClassNameForType(const CIRGenModule &cgm, const Type *ty) {
   case Type::Atomic:
   // FIXME: GCC treats block pointers as fundamental types?!
   case Type::BlockPointer:
-    cgm.errorNYI("VTableClassNameForType: __fundamental_type_info");
-    break;
+    return "_ZTVN10__cxxabiv123__fundamental_type_infoE";
   case Type::ConstantArray:
   case Type::IncompleteArray:
   case Type::VariableArray:

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -1793,12 +1793,20 @@ CIRToLLVMGlobalOpLowering::getComdatAttr(cir::GlobalOp &op,
   if (!comdatOp) {
     builder.setInsertionPointToStart(module.getBody());
     comdatOp =
-        builder.create<mlir::LLVM::ComdatOp>(module.getLoc(), comdatName);
+        mlir::LLVM::ComdatOp::create(builder, module.getLoc(), comdatName);
+  }
+
+  if (auto comdatSelector = comdatOp.lookupSymbol<mlir::LLVM::ComdatSelectorOp>(
+          op.getSymName())) {
+    return mlir::SymbolRefAttr::get(
+        builder.getContext(), comdatName,
+        mlir::FlatSymbolRefAttr::get(comdatSelector.getSymNameAttr()));
   }
 
   builder.setInsertionPointToStart(&comdatOp.getBody().back());
-  auto selectorOp = builder.create<mlir::LLVM::ComdatSelectorOp>(
-      comdatOp.getLoc(), op.getSymName(), mlir::LLVM::comdat::Comdat::Any);
+  auto selectorOp = mlir::LLVM::ComdatSelectorOp::create(
+      builder, comdatOp.getLoc(), op.getSymName(),
+      mlir::LLVM::comdat::Comdat::Any);
   return mlir::SymbolRefAttr::get(
       builder.getContext(), comdatName,
       mlir::FlatSymbolRefAttr::get(selectorOp.getSymNameAttr()));

clang/test/CIR/CodeGen/throws.cpp

@@ -123,3 +123,24 @@ void paren_expr() { (throw 0, 1 + 2); }
 // OGCG: %[[EXCEPTION_ADDR:.*]] = call ptr @__cxa_allocate_exception(i64 4)
 // OGCG: store i32 0, ptr %[[EXCEPTION_ADDR]], align 16
 // OGCG: call void @__cxa_throw(ptr %[[EXCEPTION_ADDR]], ptr @_ZTIi, ptr null)
+
+void throw_complex_expr() {
+  throw __builtin_complex(1.1f, 2.2f);
+}
+
+// CIR: %[[EXCEPTION_ADDR:.*]] = cir.alloc.exception 8 -> !cir.ptr<!cir.complex<!cir.float>>
+// CIR: %[[EXCEPTION_VALUE:.*]] = cir.const #cir.const_complex<#cir.fp<1.100000e+00> : !cir.float, #cir.fp<2.200000e+00> : !cir.float> : !cir.complex<!cir.float>
+// CIR: cir.store{{.*}} %[[EXCEPTION_VALUE]], %[[EXCEPTION_ADDR]] : !cir.complex<!cir.float>, !cir.ptr<!cir.complex<!cir.float>>
+// CIR: cir.throw %[[EXCEPTION_ADDR]] : !cir.ptr<!cir.complex<!cir.float>>, @_ZTICf
+// CIR: cir.unreachable
+
+// LLVM: %[[EXCEPTION_ADDR:.*]] = call ptr @__cxa_allocate_exception(i64 8)
+// LLVM: store { float, float } { float 0x3FF19999A0000000, float 0x40019999A0000000 }, ptr %[[EXCEPTION_ADDR]], align 16
+// LLVM: call void @__cxa_throw(ptr %[[EXCEPTION_ADDR]], ptr @_ZTICf, ptr null)
+
+// OGCG: %[[EXCEPTION_ADDR:.*]] = call ptr @__cxa_allocate_exception(i64 8)
+// OGCG: %[[EXCEPTION_REAL:.*]] = getelementptr inbounds nuw { float, float }, ptr %[[EXCEPTION_ADDR]], i32 0, i32 0
+// OGCG: %[[EXCEPTION_IMAG:.*]] = getelementptr inbounds nuw { float, float }, ptr %[[EXCEPTION_ADDR]], i32 0, i32 1
+// OGCG: store float 0x3FF19999A0000000, ptr %[[EXCEPTION_REAL]], align 16
+// OGCG: store float 0x40019999A0000000, ptr %[[EXCEPTION_IMAG]], align 4
+// OGCG: call void @__cxa_throw(ptr %[[EXCEPTION_ADDR]], ptr @_ZTICf, ptr null)