// Copyright 2014 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 runtime

import (
	
	
	
	
)

const itabInitSize = 512

var (
	itabLock      mutex                               // lock for accessing itab table
	itabTable     = &itabTableInit                    // pointer to current table
	itabTableInit = itabTableType{size: itabInitSize} // starter table
)

// Note: change the formula in the mallocgc call in itabAdd if you change these fields.
type itabTableType struct {
	size    uintptr             // length of entries array. Always a power of 2.
	count   uintptr             // current number of filled entries.
	entries [itabInitSize]*itab // really [size] large
}

func ( *interfacetype,  *_type) uintptr {
	// compiler has provided some good hash codes for us.
	return uintptr(.Type.Hash ^ .Hash)
}

func ( *interfacetype,  *_type,  bool) *itab {
	if len(.Methods) == 0 {
		throw("internal error - misuse of itab")
	}

	// easy case
	if .TFlag&abi.TFlagUncommon == 0 {
		if  {
			return nil
		}
		 := toRType(&.Type).nameOff(.Methods[0].Name)
		panic(&TypeAssertionError{nil, , &.Type, .Name()})
	}

	var  *itab

	// First, look in the existing table to see if we can find the itab we need.
	// This is by far the most common case, so do it without locks.
	// Use atomic to ensure we see any previous writes done by the thread
	// that updates the itabTable field (with atomic.Storep in itabAdd).
	 := (*itabTableType)(atomic.Loadp(unsafe.Pointer(&itabTable)))
	if  = .find(, );  != nil {
		goto 
	}

	// Not found.  Grab the lock and try again.
	lock(&itabLock)
	if  = itabTable.find(, );  != nil {
		unlock(&itabLock)
		goto 
	}

	// Entry doesn't exist yet. Make a new entry & add it.
	 = (*itab)(persistentalloc(unsafe.Sizeof(itab{})+uintptr(len(.Methods)-1)*goarch.PtrSize, 0, &memstats.other_sys))
	.inter = 
	._type = 
	// The hash is used in type switches. However, compiler statically generates itab's
	// for all interface/type pairs used in switches (which are added to itabTable
	// in itabsinit). The dynamically-generated itab's never participate in type switches,
	// and thus the hash is irrelevant.
	// Note: m.hash is _not_ the hash used for the runtime itabTable hash table.
	.hash = 0
	.init()
	itabAdd()
	unlock(&itabLock)
:
	if .fun[0] != 0 {
		return 
	}
	if  {
		return nil
	}
	// this can only happen if the conversion
	// was already done once using the , ok form
	// and we have a cached negative result.
	// The cached result doesn't record which
	// interface function was missing, so initialize
	// the itab again to get the missing function name.
	panic(&TypeAssertionError{concrete: , asserted: &.Type, missingMethod: .init()})
}

// find finds the given interface/type pair in t.
// Returns nil if the given interface/type pair isn't present.
func ( *itabTableType) ( *interfacetype,  *_type) *itab {
	// Implemented using quadratic probing.
	// Probe sequence is h(i) = h0 + i*(i+1)/2 mod 2^k.
	// We're guaranteed to hit all table entries using this probe sequence.
	 := .size - 1
	 := itabHashFunc(, ) & 
	for  := uintptr(1); ; ++ {
		 := (**itab)(add(unsafe.Pointer(&.entries), *goarch.PtrSize))
		// Use atomic read here so if we see m != nil, we also see
		// the initializations of the fields of m.
		// m := *p
		 := (*itab)(atomic.Loadp(unsafe.Pointer()))
		if  == nil {
			return nil
		}
		if .inter ==  && ._type ==  {
			return 
		}
		 += 
		 &= 
	}
}

// itabAdd adds the given itab to the itab hash table.
// itabLock must be held.
func ( *itab) {
	// Bugs can lead to calling this while mallocing is set,
	// typically because this is called while panicking.
	// Crash reliably, rather than only when we need to grow
	// the hash table.
	if getg().m.mallocing != 0 {
		throw("malloc deadlock")
	}

	 := itabTable
	if .count >= 3*(.size/4) { // 75% load factor
		// Grow hash table.
		// t2 = new(itabTableType) + some additional entries
		// We lie and tell malloc we want pointer-free memory because
		// all the pointed-to values are not in the heap.
		 := (*itabTableType)(mallocgc((2+2*.size)*goarch.PtrSize, nil, true))
		.size = .size * 2

		// Copy over entries.
		// Note: while copying, other threads may look for an itab and
		// fail to find it. That's ok, they will then try to get the itab lock
		// and as a consequence wait until this copying is complete.
		iterate_itabs(.add)
		if .count != .count {
			throw("mismatched count during itab table copy")
		}
		// Publish new hash table. Use an atomic write: see comment in getitab.
		atomicstorep(unsafe.Pointer(&itabTable), unsafe.Pointer())
		// Adopt the new table as our own.
		 = itabTable
		// Note: the old table can be GC'ed here.
	}
	.add()
}

// add adds the given itab to itab table t.
// itabLock must be held.
func ( *itabTableType) ( *itab) {
	// See comment in find about the probe sequence.
	// Insert new itab in the first empty spot in the probe sequence.
	 := .size - 1
	 := itabHashFunc(.inter, ._type) & 
	for  := uintptr(1); ; ++ {
		 := (**itab)(add(unsafe.Pointer(&.entries), *goarch.PtrSize))
		 := *
		if  ==  {
			// A given itab may be used in more than one module
			// and thanks to the way global symbol resolution works, the
			// pointed-to itab may already have been inserted into the
			// global 'hash'.
			return
		}
		if  == nil {
			// Use atomic write here so if a reader sees m, it also
			// sees the correctly initialized fields of m.
			// NoWB is ok because m is not in heap memory.
			// *p = m
			atomic.StorepNoWB(unsafe.Pointer(), unsafe.Pointer())
			.count++
			return
		}
		 += 
		 &= 
	}
}

// init fills in the m.fun array with all the code pointers for
// the m.inter/m._type pair. If the type does not implement the interface,
// it sets m.fun[0] to 0 and returns the name of an interface function that is missing.
// It is ok to call this multiple times on the same m, even concurrently.
func ( *itab) () string {
	 := .inter
	 := ._type
	 := .Uncommon()

	// both inter and typ have method sorted by name,
	// and interface names are unique,
	// so can iterate over both in lock step;
	// the loop is O(ni+nt) not O(ni*nt).
	 := len(.Methods)
	 := int(.Mcount)
	 := (*[1 << 16]abi.Method)(add(unsafe.Pointer(), uintptr(.Moff)))[::]
	 := 0
	 := (*[1 << 16]unsafe.Pointer)(unsafe.Pointer(&.fun[0]))[::]
	var  unsafe.Pointer
:
	for  := 0;  < ; ++ {
		 := &.Methods[]
		 := toRType(&.Type).typeOff(.Typ)
		 := toRType(&.Type).nameOff(.Name)
		 := .Name()
		 := pkgPath()
		if  == "" {
			 = .PkgPath.Name()
		}
		for ;  < ; ++ {
			 := &[]
			 := toRType()
			 := .nameOff(.Name)
			if .typeOff(.Mtyp) ==  && .Name() ==  {
				 := pkgPath()
				if  == "" {
					 = .nameOff(.PkgPath).Name()
				}
				if .IsExported() ||  ==  {
					if  != nil {
						 := .textOff(.Ifn)
						if  == 0 {
							 =  // we'll set m.fun[0] at the end
						} else {
							[] = 
						}
					}
					continue 
				}
			}
		}
		// didn't find method
		.fun[0] = 0
		return 
	}
	.fun[0] = uintptr()
	return ""
}

func () {
	lockInit(&itabLock, lockRankItab)
	lock(&itabLock)
	for ,  := range activeModules() {
		for ,  := range .itablinks {
			itabAdd()
		}
	}
	unlock(&itabLock)
}

// panicdottypeE is called when doing an e.(T) conversion and the conversion fails.
// have = the dynamic type we have.
// want = the static type we're trying to convert to.
// iface = the static type we're converting from.
func (, ,  *_type) {
	panic(&TypeAssertionError{, , , ""})
}

// panicdottypeI is called when doing an i.(T) conversion and the conversion fails.
// Same args as panicdottypeE, but "have" is the dynamic itab we have.
func ( *itab, ,  *_type) {
	var  *_type
	if  != nil {
		 = ._type
	}
	panicdottypeE(, , )
}

// panicnildottype is called when doing an i.(T) conversion and the interface i is nil.
// want = the static type we're trying to convert to.
func ( *_type) {
	panic(&TypeAssertionError{nil, nil, , ""})
	// TODO: Add the static type we're converting from as well.
	// It might generate a better error message.
	// Just to match other nil conversion errors, we don't for now.
}

// The specialized convTx routines need a type descriptor to use when calling mallocgc.
// We don't need the type to be exact, just to have the correct size, alignment, and pointer-ness.
// However, when debugging, it'd be nice to have some indication in mallocgc where the types came from,
// so we use named types here.
// We then construct interface values of these types,
// and then extract the type word to use as needed.
type (
	uint16InterfacePtr uint16
	uint32InterfacePtr uint32
	uint64InterfacePtr uint64
	stringInterfacePtr string
	sliceInterfacePtr  []byte
)

var (
	uint16Eface any = uint16InterfacePtr(0)
	uint32Eface any = uint32InterfacePtr(0)
	uint64Eface any = uint64InterfacePtr(0)
	stringEface any = stringInterfacePtr("")
	sliceEface  any = sliceInterfacePtr(nil)

	uint16Type *_type = efaceOf(&uint16Eface)._type
	uint32Type *_type = efaceOf(&uint32Eface)._type
	uint64Type *_type = efaceOf(&uint64Eface)._type
	stringType *_type = efaceOf(&stringEface)._type
	sliceType  *_type = efaceOf(&sliceEface)._type
)

// The conv and assert functions below do very similar things.
// The convXXX functions are guaranteed by the compiler to succeed.
// The assertXXX functions may fail (either panicking or returning false,
// depending on whether they are 1-result or 2-result).
// The convXXX functions succeed on a nil input, whereas the assertXXX
// functions fail on a nil input.

// convT converts a value of type t, which is pointed to by v, to a pointer that can
// be used as the second word of an interface value.
func ( *_type,  unsafe.Pointer) unsafe.Pointer {
	if raceenabled {
		raceReadObjectPC(, , getcallerpc(), abi.FuncPCABIInternal())
	}
	if msanenabled {
		msanread(, .Size_)
	}
	if asanenabled {
		asanread(, .Size_)
	}
	 := mallocgc(.Size_, , true)
	typedmemmove(, , )
	return 
}
func ( *_type,  unsafe.Pointer) unsafe.Pointer {
	// TODO: maybe take size instead of type?
	if raceenabled {
		raceReadObjectPC(, , getcallerpc(), abi.FuncPCABIInternal())
	}
	if msanenabled {
		msanread(, .Size_)
	}
	if asanenabled {
		asanread(, .Size_)
	}

	 := mallocgc(.Size_, , false)
	memmove(, , .Size_)
	return 
}

func ( uint16) ( unsafe.Pointer) {
	if  < uint16(len(staticuint64s)) {
		 = unsafe.Pointer(&staticuint64s[])
		if goarch.BigEndian {
			 = add(, 6)
		}
	} else {
		 = mallocgc(2, uint16Type, false)
		*(*uint16)() = 
	}
	return
}

func ( uint32) ( unsafe.Pointer) {
	if  < uint32(len(staticuint64s)) {
		 = unsafe.Pointer(&staticuint64s[])
		if goarch.BigEndian {
			 = add(, 4)
		}
	} else {
		 = mallocgc(4, uint32Type, false)
		*(*uint32)() = 
	}
	return
}

func ( uint64) ( unsafe.Pointer) {
	if  < uint64(len(staticuint64s)) {
		 = unsafe.Pointer(&staticuint64s[])
	} else {
		 = mallocgc(8, uint64Type, false)
		*(*uint64)() = 
	}
	return
}

func ( string) ( unsafe.Pointer) {
	if  == "" {
		 = unsafe.Pointer(&zeroVal[0])
	} else {
		 = mallocgc(unsafe.Sizeof(), stringType, true)
		*(*string)() = 
	}
	return
}

func ( []byte) ( unsafe.Pointer) {
	// Note: this must work for any element type, not just byte.
	if (*slice)(unsafe.Pointer(&)).array == nil {
		 = unsafe.Pointer(&zeroVal[0])
	} else {
		 = mallocgc(unsafe.Sizeof(), sliceType, true)
		*(*[]byte)() = 
	}
	return
}

// convI2I returns the new itab to be used for the destination value
// when converting a value with itab src to the dst interface.
func ( *interfacetype,  *itab) *itab {
	if  == nil {
		return nil
	}
	if .inter ==  {
		return 
	}
	return getitab(, ._type, false)
}

func ( *interfacetype,  *itab) *itab {
	if  == nil {
		// explicit conversions require non-nil interface value.
		panic(&TypeAssertionError{nil, nil, &.Type, ""})
	}
	if .inter ==  {
		return 
	}
	return getitab(, ._type, false)
}

func ( *interfacetype,  iface) ( iface) {
	 := .tab
	if  == nil {
		return
	}
	if .inter !=  {
		 = getitab(, ._type, true)
		if  == nil {
			return
		}
	}
	.tab = 
	.data = .data
	return
}

func ( *interfacetype,  *_type) *itab {
	if  == nil {
		// explicit conversions require non-nil interface value.
		panic(&TypeAssertionError{nil, nil, &.Type, ""})
	}
	return getitab(, , false)
}

func ( *interfacetype,  eface) ( iface) {
	 := ._type
	if  == nil {
		return
	}
	 := getitab(, , true)
	if  == nil {
		return
	}
	.tab = 
	.data = .data
	return
}

//go:linkname reflect_ifaceE2I reflect.ifaceE2I
func ( *interfacetype,  eface,  *iface) {
	* = iface{assertE2I(, ._type), .data}
}

//go:linkname reflectlite_ifaceE2I internal/reflectlite.ifaceE2I
func ( *interfacetype,  eface,  *iface) {
	* = iface{assertE2I(, ._type), .data}
}

func ( func(*itab)) {
	// Note: only runs during stop the world or with itabLock held,
	// so no other locks/atomics needed.
	 := itabTable
	for  := uintptr(0);  < .size; ++ {
		 := *(**itab)(add(unsafe.Pointer(&.entries), *goarch.PtrSize))
		if  != nil {
			()
		}
	}
}

// staticuint64s is used to avoid allocating in convTx for small integer values.
var staticuint64s = [...]uint64{
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
	0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
	0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
	0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
	0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
	0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
	0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
	0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
	0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
}

// The linker redirects a reference of a method that it determined
// unreachable to a reference to this function, so it will throw if
// ever called.
func () {
	throw("unreachable method called. linker bug?")
}