src/internal/abi/compiletype.go

// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package abi

// These functions are the build-time version of the Go type data structures.

// Their contents must be kept in sync with their definitions.
// Because the host and target type sizes can differ, the compiler and
// linker cannot use the host information that they might get from
// either unsafe.Sizeof and Alignof, nor runtime, reflect, or reflectlite.

// CommonSize returns sizeof(Type) for a compilation target with a given ptrSize
func CommonSize(ptrSize int) int { return 4*ptrSize + 8 + 8 }

// StructFieldSize returns sizeof(StructField) for a compilation target with a given ptrSize
func StructFieldSize(ptrSize int) int { return 3 * ptrSize }

// UncommonSize returns sizeof(UncommonType).  This currently does not depend on ptrSize.
// This exported function is in an internal package, so it may change to depend on ptrSize in the future.
func UncommonSize() uint64 { return 4 + 2 + 2 + 4 + 4 }

// TFlagOff returns the offset of Type.TFlag for a compilation target with a given ptrSize
func TFlagOff(ptrSize int) int { return 2*ptrSize + 4 }

// ITabTypeOff returns the offset of ITab.Type for a compilation target with a given ptrSize
func ITabTypeOff(ptrSize int) int { return ptrSize }