================
@@ -400,13 +400,126 @@ def VoidPtr : Type<
"cir::VoidType::get($_builder.getContext()))"> {
}
+//===----------------------------------------------------------------------===//
+// StructType
+//
+// The base type for all RecordDecls.
+//===----------------------------------------------------------------------===//
+
+def CIR_StructType : CIR_Type<"Struct", "struct",
+ [
+ DeclareTypeInterfaceMethods<DataLayoutTypeInterface>,
+ MutableType,
+ ]> {
+ let summary = "CIR struct type";
+ let description = [{
+ Each unique clang::RecordDecl is mapped to a `cir.struct` and any object in
+ C/C++ that has a struct type will have a `cir.struct` in CIR.
+
+ There are three possible formats for this type:
+
+ - Identified and complete structs: unique name and a known body.
+ - Identified and incomplete structs: unique name and unknown body.
+ - Anonymous structs: no name and a known body.
+
+ Identified structs are uniqued by their name, and anonymous structs are
+ uniqued by their body. This means that two anonymous structs with the same
+ body will be the same type, and two identified structs with the same name
+ will be the same type. Attempting to build a struct with an existing name,
+ but a different body will result in an error.
+
+ A few examples:
+
+ ```mlir
+ !complete = !cir.struct<struct "complete" {!cir.int<u, 8>}>
+ !incomplete = !cir.struct<struct "incomplete" incomplete>
+ !anonymous = !cir.struct<struct {!cir.int<u, 8>}>
+ ```
+
+ Incomplete structs are mutable, meaning they can be later completed with a
+ body automatically updating in place every type in the code that uses the
+ incomplete struct. Mutability allows for recursive types to be represented,
+ meaning the struct can have members that refer to itself. This is useful
for
+ representing recursive records and is implemented through a special syntax.
+ In the example below, the `Node` struct has a member that is a pointer to a
+ `Node` struct:
+
+ ```mlir
+ !struct = !cir.struct<struct "Node" {!cir.ptr<!cir.struct<struct
----------------
erichkeane wrote:
Curious why it is `!cir.struct<struct` "Node"`. Why the duplication of
`struct` there?
Presumably because it might be `class` or `union` in teh second place?
https://github.com/llvm/llvm-project/pull/135105
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