go/src/runtime/mbarrier.go

// typedmemmove copies a value of type typ to dst from src.
// Must be nosplit, see #16026.
//
// TODO: Perfect for go:nosplitrec since we can't have a safe point
// anywhere in the bulk barrier or memmove.
//
// typedmemmove should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/RomiChan/protobuf
//   - github.com/segmentio/encoding
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname typedmemmove
//go:nosplit
func typedmemmove(typ *abi.Type, dst, src unsafe.Pointer) { … }

// wbZero performs the write barrier operations necessary before
// zeroing a region of memory at address dst of type typ.
// Does not actually do the zeroing.
//
//go:nowritebarrierrec
//go:nosplit
func wbZero(typ *_type, dst unsafe.Pointer) { … }

// wbMove performs the write barrier operations necessary before
// copying a region of memory from src to dst of type typ.
// Does not actually do the copying.
//
//go:nowritebarrierrec
//go:nosplit
func wbMove(typ *_type, dst, src unsafe.Pointer) { … }

// reflect_typedmemmove is meant for package reflect,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - gitee.com/quant1x/gox
//   - github.com/goccy/json
//   - github.com/modern-go/reflect2
//   - github.com/ugorji/go/codec
//   - github.com/v2pro/plz
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname reflect_typedmemmove reflect.typedmemmove
func reflect_typedmemmove(typ *_type, dst, src unsafe.Pointer) { … }

//go:linkname reflectlite_typedmemmove internal/reflectlite.typedmemmove
func reflectlite_typedmemmove(typ *_type, dst, src unsafe.Pointer) { … }

//go:linkname maps_typedmemmove internal/runtime/maps.typedmemmove
func maps_typedmemmove(typ *_type, dst, src unsafe.Pointer) { … }

// reflectcallmove is invoked by reflectcall to copy the return values
// out of the stack and into the heap, invoking the necessary write
// barriers. dst, src, and size describe the return value area to
// copy. typ describes the entire frame (not just the return values).
// typ may be nil, which indicates write barriers are not needed.
//
// It must be nosplit and must only call nosplit functions because the
// stack map of reflectcall is wrong.
//
//go:nosplit
func reflectcallmove(typ *_type, dst, src unsafe.Pointer, size uintptr, regs *abi.RegArgs) { … }

// typedslicecopy should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/segmentio/encoding
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname typedslicecopy
//go:nosplit
func typedslicecopy(typ *_type, dstPtr unsafe.Pointer, dstLen int, srcPtr unsafe.Pointer, srcLen int) int { … }

// reflect_typedslicecopy is meant for package reflect,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - gitee.com/quant1x/gox
//   - github.com/modern-go/reflect2
//   - github.com/RomiChan/protobuf
//   - github.com/segmentio/encoding
//   - github.com/v2pro/plz
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname reflect_typedslicecopy reflect.typedslicecopy
func reflect_typedslicecopy(elemType *_type, dst, src slice) int { … }

// typedmemclr clears the typed memory at ptr with type typ. The
// memory at ptr must already be initialized (and hence in type-safe
// state). If the memory is being initialized for the first time, see
// memclrNoHeapPointers.
//
// If the caller knows that typ has pointers, it can alternatively
// call memclrHasPointers.
//
// TODO: A "go:nosplitrec" annotation would be perfect for this.
//
//go:nosplit
func typedmemclr(typ *_type, ptr unsafe.Pointer) { … }

// reflect_typedslicecopy is meant for package reflect,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/ugorji/go/codec
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname reflect_typedmemclr reflect.typedmemclr
func reflect_typedmemclr(typ *_type, ptr unsafe.Pointer) { … }

//go:linkname maps_typedmemclr internal/runtime/maps.typedmemclr
func maps_typedmemclr(typ *_type, ptr unsafe.Pointer) { … }

//go:linkname reflect_typedmemclrpartial reflect.typedmemclrpartial
func reflect_typedmemclrpartial(typ *_type, ptr unsafe.Pointer, off, size uintptr) { … }

//go:linkname reflect_typedarrayclear reflect.typedarrayclear
func reflect_typedarrayclear(typ *_type, ptr unsafe.Pointer, len int) { … }

// memclrHasPointers clears n bytes of typed memory starting at ptr.
// The caller must ensure that the type of the object at ptr has
// pointers, usually by checking typ.PtrBytes. However, ptr
// does not have to point to the start of the allocation.
//
// memclrHasPointers should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/bytedance/sonic
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname memclrHasPointers
//go:nosplit
func memclrHasPointers(ptr unsafe.Pointer, n uintptr) { … }