Representation
An abi.Type struct represents type information common for all data types:
// Type is the runtime representation of a Go type.
type Type struct {
Size_ uintptr
PtrBytes uintptr // number of (prefix) bytes in the type that can contain pointers
Hash uint32 // hash of type; avoids computation in hash tables
TFlag TFlag // extra type information flags
Align_ uint8 // alignment of variable with this type
FieldAlign_ uint8 // alignment of struct field with this type
Kind_ uint8 // enumeration for C
// function for comparing objects of this type
// (ptr to object A, ptr to object B) -> ==?
Equal func(unsafe.Pointer, unsafe.Pointer) bool
// GCData stores the GC type data for the garbage collector.
// If the KindGCProg bit is set in kind, GCData is a GC program.
// Otherwise it is a ptrmask bitmap. See mbitmap.go for details.
GCData *byte
Str NameOff // string form
PtrToThis TypeOff // type for pointer to this type, may be zero
}Data types requiring additional information are represented by their respective structs: slice, struct, interface, map, etc. All this structs embed the abi.Type struct and add additional fields
For example, abi.UncommonType stores information about methods defined on a type:
// UncommonType is present only for defined types or types with methods
// (if T is a defined type, the uncommonTypes for T and *T have methods).
// Using a pointer to this struct reduces the overall size required
// to describe a non-defined type with no methods.
type UncommonType struct {
PkgPath NameOff // import path; empty for built-in types like int, string
Mcount uint16 // number of methods
Xcount uint16 // number of exported methods
Moff uint32 // offset from this uncommontype to [mcount]Method
_ uint32 // unused
}It’s important to note that type information structures are computed at compile-time