compiler, runtime, reflect: generate type-specific hash/equal (#5359)

* compiler, runtime, reflect: generate type-specific hash/equal for composite map keys

For map keys that are not trivially binary-comparable, the compiler now
generates type-specific hash and equal functions as LLVM IR instead of
going through the interface+reflection path. This covers comparable
types: strings, floats, complex numbers, interfaces, channels, and
composites containing any mix of these.

Previously, maps with composite keys containing strings or floats
converted the key to interface{}, hashed via reflection, and compared
through interface equality. Now the compiler walks struct fields and
array elements directly, dispatching to the right runtime helper for
each field type and storing keys at their actual type.

Struct keys are always handled field-by-field so padding bytes do not
affect equality or hashing. Blank fields are ignored, matching Go
equality. Generated hash/equal function names use canonical underlying
type structure so structurally identical key types can share generated
functions. Padding zeroing before map operations is no longer needed
because structs no longer use the binary key path.

Also fix reflect map iteration for interface-keyed maps: MapIter.Key
returns an interface Value for map[interface{}] keys instead of
unpacking to the concrete key kind.

* compiler: generate loops for array map key hash/equal

Previously, array key hash and equal functions were unrolled at compile
time, generating one block of IR per element. For large arrays like
[1000]int inside a struct with non-binary fields, this caused code
explosion.

Now, binary-element arrays dispatch directly to hash32/memequal for the
whole array. Non-binary-element arrays generate an LLVM IR loop. The
equal loop short-circuits on the first mismatch.

Small arrays are still unrolled instead of looping, keeping the simple
cases compact.

* reflect: fix at-runtime map issues from review, and more found locally

Maps created through reflect.MakeMap need hash/equal behavior that
matches compiler-created maps. Add hashmapMakeReflect for composite key
types, using runtime closures that reconstruct interface{} values from
raw key bytes and delegate to the interface hash and equality paths.

Interface-keyed maps are already stored as interface values, so use the
existing interface hash/equal helpers directly for those. This keeps
reflect insert, lookup, delete, and compiled lookup paths consistent.

Also fix addressable small values used as interface map keys or
interface map values. loadSmallValue puts small indirect values back in
the pointer-sized interface data field the same way valueInterfaceUnsafe
does.

* compiler, interp, reflect: fix pointer map literals; remove interface fallback

Package-level map literals with pointer keys (both *T and
unsafe.Pointer) crash the compiler: the interp pass panics when trying
to hash pointer data as raw bytes, because pointer values in the interp
memory model are symbolic identities that do not fit in a byte.

Fix this by setting a recoverable error flag instead of panicking. The
interp detects the error after each instruction and defers the map
insert to runtime init code, where real addresses are available for
hashing. This matches how the interp already handles other operations
it cannot evaluate at compile time.

With this fix, unsafe.Pointer can also be classified as a binary map
key, which was the last type requiring the interface-based fallback.
Since all comparable types now use either the binary or the
compiler-generated hash/equal path, remove the interface fallback from
the compiler and reflect packages.

* compiler, transform: always pass hash/equal function pointers to hashmapMakeGeneric

The compiler now always resolves the hash and equal functions at compile
time and passes them directly to hashmapMakeGeneric, instead of passing
an algorithm enum to hashmapMake and resolving at runtime. For string
keys, the runtime hashmapStringPtrHash/hashmapStringEqual functions are
referenced directly. For binary keys, hash32/memequal are referenced.

The old hashmapMake with alg enum is retained for reflect, which still
needs runtime resolution when creating maps dynamically.

The OptimizeMaps transform pass is updated to handle both hashmapMake
and hashmapMakeGeneric, and to recognize hashmapGenericSet in addition
to hashmapBinarySet and hashmapStringSet. The now-unused
hashmapCanGenerateHashEqual helper is removed.

* runtime: store large map keys and values indirectly

When a map key or value exceeds 128 bytes, the bucket now stores a
pointer to separately allocated memory instead of the data inline. This
matches Go's MapMaxKeyBytes/MapMaxElemBytes threshold and prevents
bucket sizes from exploding for large key/value types.

For example, map[[256]byte]int previously used 2128 bytes per bucket
(16 header + 256*8 keys + 8*8 values); now it uses 144 bytes per bucket
(16 header + 8*8 pointers + 8*8 values).

The indirection is fully encapsulated in the runtime via helper
functions. Store the computed key and value slot sizes on the hashmap so
all runtime and reflect paths use the same bucket layout, including
non-indirect keys and values.

Add big-key golden coverage and benchmarks. Make the benchmark vary
enough key bytes to exercise hashing.

src/internal/reflectlite/value.go

@@ -146,6 +146,19 @@ func TypeAssert[T any](v Value) (T, bool) {
 
 // valueInterfaceUnsafe is used by the runtime to hash map keys. It should not
 // be subject to the isExported check.
+// loadSmallValue loads a value of size <= sizeof(uintptr) from ptr into
+// a pointer-sized value suitable for storing in an interface's data field.
+func loadSmallValue(ptr unsafe.Pointer, size uintptr) unsafe.Pointer {
+	if size == unsafe.Sizeof(uintptr(0)) {
+		return *(*unsafe.Pointer)(ptr)
+	}
+	var value uintptr
+	for j := size; j != 0; j-- {
+		value = (value << 8) | uintptr(*(*uint8)(unsafe.Add(ptr, j-1)))
+	}
+	return unsafe.Pointer(value)
+}
+
 func valueInterfaceUnsafe(v Value) interface{} {
 	if v.typecode.Kind() == Interface {
 		// The value itself is an interface. This can happen when getting the
@@ -158,11 +171,7 @@ func valueInterfaceUnsafe(v Value) interface{} {
 	if v.isIndirect() && v.typecode.Size() <= unsafe.Sizeof(uintptr(0)) {
 		// Value was indirect but must be put back directly in the interface
 		// value.
-		var value uintptr
-		for j := v.typecode.Size(); j != 0; j-- {
-			value = (value << 8) | uintptr(*(*uint8)(unsafe.Add(v.value, j-1)))
-		}
-		v.value = unsafe.Pointer(value)
+		v.value = loadSmallValue(v.value, v.typecode.Size())
 	}
 	return composeInterface(unsafe.Pointer(v.typecode), v.value)
 }
@@ -1085,18 +1094,8 @@ func (v Value) MapKeys() []Value {
 	k := New(v.typecode.Key())
 	e := New(v.typecode.Elem())
 
-	keyType := v.typecode.key()
-	keyTypeIsEmptyInterface := keyType.Kind() == Interface && keyType.NumMethod() == 0
-	shouldUnpackInterface := !keyTypeIsEmptyInterface && keyType.Kind() != String && !keyType.isBinary()
-
 	for hashmapNext(v.pointer(), it, k.value, e.value) {
-		if shouldUnpackInterface {
-			intf := *(*interface{})(k.value)
-			v := ValueOf(intf)
-			keys = append(keys, v)
-		} else {
-			keys = append(keys, k.Elem())
-		}
+		keys = append(keys, k.Elem())
 		k = New(v.typecode.Key())
 	}
 
@@ -1109,9 +1108,40 @@ func hashmapStringGet(m unsafe.Pointer, key string, value unsafe.Pointer, valueS
 //go:linkname hashmapBinaryGet runtime.hashmapBinaryGet
 func hashmapBinaryGet(m unsafe.Pointer, key, value unsafe.Pointer, valueSize uintptr) bool
 
-//go:linkname hashmapInterfaceGet runtime.hashmapInterfaceGet
-func hashmapInterfaceGet(m unsafe.Pointer, key interface{}, value unsafe.Pointer, valueSize uintptr) bool
+//go:linkname hashmapGenericGet runtime.hashmapGenericGet
+func hashmapGenericGet(m unsafe.Pointer, key, value unsafe.Pointer, valueSize uintptr) bool
 
+// genericKeyPtr returns a pointer to key data suitable for passing to the
+// hashmapGeneric* functions. When the map's key type is an interface,
+// special handling is needed: if the key Value already holds an interface
+// (e.g. from MapKeys iteration), its memory already contains the
+// {typecode, data} pair the hashmap expects, so we use it directly.
+// If the key is a concrete type being assigned to an interface-keyed map,
+// we compose the interface first.
+func genericKeyPtr(vkey *RawType, key Value) unsafe.Pointer {
+	if vkey.Kind() == Interface {
+		if key.Kind() == Interface {
+			// Key is already an interface value stored indirectly;
+			// key.value points to {typecode, data}.
+			return key.value
+		}
+		// Concrete value being used as an interface key.
+		// For small addressable values, key.value is a pointer to
+		// the data, but the interface value field stores the data
+		// directly; load it using the same endian-safe approach as
+		// valueInterfaceUnsafe.
+		val := key.value
+		if key.isIndirect() && key.typecode.Size() <= unsafe.Sizeof(uintptr(0)) {
+			val = loadSmallValue(key.value, key.typecode.Size())
+		}
+		intf := composeInterface(unsafe.Pointer(key.typecode), val)
+		return unsafe.Pointer(&intf)
+	}
+	if key.isIndirect() || key.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
+		return key.value
+	}
+	return unsafe.Pointer(&key.value)
+}
 func (v Value) MapIndex(key Value) Value {
 	if v.Kind() != Map {
 		panic(&ValueError{Method: "MapIndex", Kind: v.Kind()})
@@ -1140,13 +1170,16 @@ func (v Value) MapIndex(key Value) Value {
 		} else {
 			keyptr = unsafe.Pointer(&key.value)
 		}
-		//TODO(dgryski): zero out padding bytes in key, if any
 		if ok := hashmapBinaryGet(v.pointer(), keyptr, elem.value, elemType.Size()); !ok {
 			return Value{}
 		}
 		return elem.Elem()
 	} else {
-		if ok := hashmapInterfaceGet(v.pointer(), key.Interface(), elem.value, elemType.Size()); !ok {
+		// Compiler-generated hash/equal path: keys are stored at their
+		// actual type. Use hashmapGenericGet which dispatches through the
+		// map's own keyHash/keyEqual function pointers.
+		keyptr := genericKeyPtr(vkey, key)
+		if ok := hashmapGenericGet(v.pointer(), keyptr, elem.value, elemType.Size()); !ok {
 			return Value{}
 		}
 		return elem.Elem()
@@ -1171,8 +1204,7 @@ type MapIter struct {
 	key Value
 	val Value
 
-	valid              bool
-	unpackKeyInterface bool
+	valid bool
 }
 
 func (it *MapIter) Key() Value {
@@ -1180,12 +1212,6 @@ func (it *MapIter) Key() Value {
 		panic("reflect.MapIter.Key called on invalid iterator")
 	}
 
-	if it.unpackKeyInterface {
-		intf := *(*interface{})(it.key.value)
-		v := ValueOf(intf)
-		return v
-	}
-
 	return it.key.Elem()
 }
 
@@ -1218,15 +1244,9 @@ func (iter *MapIter) Reset(v Value) {
 		panic(&ValueError{Method: "MapRange", Kind: v.Kind()})
 	}
 
-	keyType := v.typecode.key()
-
-	keyTypeIsEmptyInterface := keyType.Kind() == Interface && keyType.NumMethod() == 0
-	shouldUnpackInterface := !keyTypeIsEmptyInterface && keyType.Kind() != String && !keyType.isBinary()
-
 	*iter = MapIter{
-		m:                  v,
-		it:                 hashmapNewIterator(),
-		unpackKeyInterface: shouldUnpackInterface,
+		m:  v,
+		it: hashmapNewIterator(),
 	}
 }
 
@@ -1969,8 +1989,8 @@ func hashmapStringSet(m unsafe.Pointer, key string, value unsafe.Pointer)
 //go:linkname hashmapBinarySet runtime.hashmapBinarySet
 func hashmapBinarySet(m unsafe.Pointer, key, value unsafe.Pointer)
 
-//go:linkname hashmapInterfaceSet runtime.hashmapInterfaceSet
-func hashmapInterfaceSet(m unsafe.Pointer, key interface{}, value unsafe.Pointer)
+//go:linkname hashmapGenericSet runtime.hashmapGenericSet
+func hashmapGenericSet(m unsafe.Pointer, key, value unsafe.Pointer)
 
 //go:linkname hashmapStringDelete runtime.hashmapStringDelete
 func hashmapStringDelete(m unsafe.Pointer, key string)
@@ -1978,8 +1998,8 @@ func hashmapStringDelete(m unsafe.Pointer, key string)
 //go:linkname hashmapBinaryDelete runtime.hashmapBinaryDelete
 func hashmapBinaryDelete(m unsafe.Pointer, key unsafe.Pointer)
 
-//go:linkname hashmapInterfaceDelete runtime.hashmapInterfaceDelete
-func hashmapInterfaceDelete(m unsafe.Pointer, key interface{})
+//go:linkname hashmapGenericDelete runtime.hashmapGenericDelete
+func hashmapGenericDelete(m unsafe.Pointer, key unsafe.Pointer)
 
 func (v Value) SetMapIndex(key, elem Value) {
 	v.checkRO()
@@ -2002,15 +2022,19 @@ func (v Value) SetMapIndex(key, elem Value) {
 	}
 
 	// make elem an interface if it needs to be converted
-	if v.typecode.elem().Kind() == Interface && elem.typecode.Kind() != Interface {
-		intf := composeInterface(unsafe.Pointer(elem.typecode), elem.value)
+	if !del && v.typecode.elem().Kind() == Interface && elem.typecode.Kind() != Interface {
+		val := elem.value
+		if elem.isIndirect() && elem.typecode.Size() <= unsafe.Sizeof(uintptr(0)) {
+			val = loadSmallValue(elem.value, elem.typecode.Size())
+		}
+		intf := composeInterface(unsafe.Pointer(elem.typecode), val)
 		elem = Value{
 			typecode: v.typecode.elem(),
 			value:    unsafe.Pointer(&intf),
 		}
 	}
 
-	if key.Kind() == String {
+	if vkey.Kind() == String {
 		if del {
 			hashmapStringDelete(v.pointer(), *(*string)(key.value))
 		} else {
@@ -2023,7 +2047,7 @@ func (v Value) SetMapIndex(key, elem Value) {
 			hashmapStringSet(v.pointer(), *(*string)(key.value), elemptr)
 		}
 
-	} else if key.typecode.isBinary() {
+	} else if vkey.isBinary() {
 		var keyptr unsafe.Pointer
 		if key.isIndirect() || key.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
 			keyptr = key.value
@@ -2043,8 +2067,11 @@ func (v Value) SetMapIndex(key, elem Value) {
 			hashmapBinarySet(v.pointer(), keyptr, elemptr)
 		}
 	} else {
+		// Compiler-generated hash/equal path.
+		keyptr := genericKeyPtr(vkey, key)
+
 		if del {
-			hashmapInterfaceDelete(v.pointer(), key.Interface())
+			hashmapGenericDelete(v.pointer(), keyptr)
 		} else {
 			var elemptr unsafe.Pointer
 			if elem.isIndirect() || elem.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
@@ -2053,7 +2080,7 @@ func (v Value) SetMapIndex(key, elem Value) {
 				elemptr = unsafe.Pointer(&elem.value)
 			}
 
-			hashmapInterfaceSet(v.pointer(), key.Interface(), elemptr)
+			hashmapGenericSet(v.pointer(), keyptr, elemptr)
 		}
 	}
 }
@@ -2110,6 +2137,9 @@ func (v Value) FieldByNameFunc(match func(string) bool) Value {
 //go:linkname hashmapMake runtime.hashmapMake
 func hashmapMake(keySize, valueSize uintptr, sizeHint uintptr, alg uint8) unsafe.Pointer
 
+//go:linkname hashmapMakeReflect runtime.hashmapMakeReflect
+func hashmapMakeReflect(keySize, valueSize, sizeHint uintptr, keyType unsafe.Pointer) unsafe.Pointer
+
 // MakeMapWithSize creates a new map with the specified type and initial space
 // for approximately n elements.
 func MakeMapWithSize(typ Type, n int) Value {
@@ -2118,7 +2148,6 @@ func MakeMapWithSize(typ Type, n int) Value {
 	const (
 		hashmapAlgorithmBinary uint8 = iota
 		hashmapAlgorithmString
-		hashmapAlgorithmInterface
 	)
 
 	if typ.Kind() != Map {
@@ -2132,18 +2161,19 @@ func MakeMapWithSize(typ Type, n int) Value {
 	key := typ.Key().(*RawType)
 	val := typ.Elem().(*RawType)
 
-	var alg uint8
+	var m unsafe.Pointer
 
 	if key.Kind() == String {
-		alg = hashmapAlgorithmString
+		m = hashmapMake(key.Size(), val.Size(), uintptr(n), hashmapAlgorithmString)
 	} else if key.isBinary() {
-		alg = hashmapAlgorithmBinary
+		m = hashmapMake(key.Size(), val.Size(), uintptr(n), hashmapAlgorithmBinary)
 	} else {
-		alg = hashmapAlgorithmInterface
+		// Composite key type (struct with strings, floats, etc.).
+		// Use runtime-generated hash/equal closures that walk the
+		// type structure, matching the compiler-generated functions.
+		m = hashmapMakeReflect(key.Size(), val.Size(), uintptr(n), unsafe.Pointer(key))
 	}
 
-	m := hashmapMake(key.Size(), val.Size(), uintptr(n), alg)
-
 	return Value{
 		typecode: typ.(*RawType),
 		value:    m,

src/runtime/hashmap.go

@@ -13,16 +13,27 @@ import (
 
 // The underlying hashmap structure for Go.
 type hashmap struct {
-	buckets    unsafe.Pointer // pointer to array of buckets
-	seed       uintptr
-	count      uintptr
-	keySize    uintptr // maybe this can store the key type as well? E.g. keysize == 5 means string?
-	valueSize  uintptr
-	bucketBits uint8
-	keyEqual   func(x, y unsafe.Pointer, n uintptr) bool
-	keyHash    func(key unsafe.Pointer, size, seed uintptr) uint32
+	buckets       unsafe.Pointer // pointer to array of buckets
+	seed          uintptr
+	count         uintptr
+	keySize       uintptr
+	valueSize     uintptr
+	keySlotSize   uintptr // == keySize, or sizeof(ptr) if indirect
+	valueSlotSize uintptr // == valueSize, or sizeof(ptr) if indirect
+	bucketBits    uint8
+	flags         uint8
+	keyEqual      func(x, y unsafe.Pointer, n uintptr) bool
+	keyHash       func(key unsafe.Pointer, size, seed uintptr) uint32
 }
 
+const (
+	hashmapMaxKeySize   = 128
+	hashmapMaxValueSize = 128
+
+	hashmapFlagIndirectKey   = 1 << 0
+	hashmapFlagIndirectValue = 1 << 1
+)
+
 // A hashmap bucket. A bucket is a container of 8 key/value pairs: first the
 // following two entries, then the 8 keys, then the 8 values. This somewhat odd
 // ordering is to make sure the keys and values are well aligned when one of
@@ -34,6 +45,48 @@ type hashmapBucket struct {
 	// allocated but as they're of variable size they can't be shown here.
 }
 
+// hashmapBucketHeaderSize is the offset in bytes from the start of a bucket to
+// the first key, aligned to 8 bytes. This ensures that keys requiring 8-byte
+// alignment (float64, complex128, uint64 on strict-alignment architectures
+// like MIPS) are properly aligned in the bucket.
+const hashmapBucketHeaderSize = (unsafe.Sizeof(hashmapBucket{}) + 7) &^ 7
+
+// hashmapKeySlotSize returns the size of a key slot in the bucket. For indirect
+// keys, this is the pointer size; otherwise the actual key size.
+//
+//go:inline
+func hashmapKeySlotSize(m *hashmap) uintptr {
+	return m.keySlotSize
+}
+
+// hashmapValueSlotSize returns the size of a value slot in the bucket.
+//
+//go:inline
+func hashmapValueSlotSize(m *hashmap) uintptr {
+	return m.valueSlotSize
+}
+
+// hashmapSlotKeyData returns a pointer to the actual key data for a given slot.
+// For indirect keys, the slot contains a pointer that must be dereferenced.
+//
+//go:inline
+func hashmapSlotKeyData(m *hashmap, slotKey unsafe.Pointer) unsafe.Pointer {
+	if m.flags&hashmapFlagIndirectKey != 0 {
+		return *(*unsafe.Pointer)(slotKey)
+	}
+	return slotKey
+}
+
+// hashmapSlotValueData returns a pointer to the actual value data for a given slot.
+//
+//go:inline
+func hashmapSlotValueData(m *hashmap, slotValue unsafe.Pointer) unsafe.Pointer {
+	if m.flags&hashmapFlagIndirectValue != 0 {
+		return *(*unsafe.Pointer)(slotValue)
+	}
+	return slotValue
+}
+
 type hashmapIterator struct {
 	buckets      unsafe.Pointer // pointer to array of hashapBuckets
 	numBuckets   uintptr        // length of buckets array
@@ -66,20 +119,35 @@ func hashmapMake(keySize, valueSize uintptr, sizeHint uintptr, alg uint8) *hashm
 		bucketBits++
 	}
 
-	bucketBufSize := unsafe.Sizeof(hashmapBucket{}) + keySize*8 + valueSize*8
+	var flags uint8
+	keySlotSize := keySize
+	if keySize > hashmapMaxKeySize {
+		flags |= hashmapFlagIndirectKey
+		keySlotSize = unsafe.Sizeof(unsafe.Pointer(nil))
+	}
+	valueSlotSize := valueSize
+	if valueSize > hashmapMaxValueSize {
+		flags |= hashmapFlagIndirectValue
+		valueSlotSize = unsafe.Sizeof(unsafe.Pointer(nil))
+	}
+
+	bucketBufSize := hashmapBucketHeaderSize + keySlotSize*8 + valueSlotSize*8
 	buckets := alloc(bucketBufSize*(1<<bucketBits), nil)
 
 	keyHash := hashmapKeyHashAlg(tinygo.HashmapAlgorithm(alg))
 	keyEqual := hashmapKeyEqualAlg(tinygo.HashmapAlgorithm(alg))
 
 	return &hashmap{
-		buckets:    buckets,
-		seed:       uintptr(fastrand()),
-		keySize:    keySize,
-		valueSize:  valueSize,
-		bucketBits: bucketBits,
-		keyEqual:   keyEqual,
-		keyHash:    keyHash,
+		buckets:       buckets,
+		seed:          uintptr(fastrand()),
+		keySize:       keySize,
+		valueSize:     valueSize,
+		keySlotSize:   keySlotSize,
+		valueSlotSize: valueSlotSize,
+		bucketBits:    bucketBits,
+		flags:         flags,
+		keyEqual:      keyEqual,
+		keyHash:       keyHash,
 	}
 }
 
@@ -118,8 +186,6 @@ func hashmapKeyEqualAlg(alg tinygo.HashmapAlgorithm) func(x, y unsafe.Pointer, n
 		return memequal
 	case tinygo.HashmapAlgorithmString:
 		return hashmapStringEqual
-	case tinygo.HashmapAlgorithmInterface:
-		return hashmapInterfaceEqual
 	default:
 		// compiler bug :(
 		return nil
@@ -132,8 +198,6 @@ func hashmapKeyHashAlg(alg tinygo.HashmapAlgorithm) func(key unsafe.Pointer, n,
 		return hash32
 	case tinygo.HashmapAlgorithmString:
 		return hashmapStringPtrHash
-	case tinygo.HashmapAlgorithmInterface:
-		return hashmapInterfacePtrHash
 	default:
 		// compiler bug :(
 		return nil
@@ -172,7 +236,7 @@ func hashmapLen(m *hashmap) int {
 
 //go:inline
 func hashmapBucketSize(m *hashmap) uintptr {
-	return unsafe.Sizeof(hashmapBucket{}) + uintptr(m.keySize)*8 + uintptr(m.valueSize)*8
+	return hashmapBucketHeaderSize + hashmapKeySlotSize(m)*8 + hashmapValueSlotSize(m)*8
 }
 
 //go:inline
@@ -191,16 +255,14 @@ func hashmapBucketAddrForHash(m *hashmap, hash uint32) *hashmapBucket {
 
 //go:inline
 func hashmapSlotKey(m *hashmap, bucket *hashmapBucket, slot uint8) unsafe.Pointer {
-	slotKeyOffset := unsafe.Sizeof(hashmapBucket{}) + uintptr(m.keySize)*uintptr(slot)
-	slotKey := unsafe.Add(unsafe.Pointer(bucket), slotKeyOffset)
-	return slotKey
+	slotKeyOffset := hashmapBucketHeaderSize + hashmapKeySlotSize(m)*uintptr(slot)
+	return unsafe.Add(unsafe.Pointer(bucket), slotKeyOffset)
 }
 
 //go:inline
 func hashmapSlotValue(m *hashmap, bucket *hashmapBucket, slot uint8) unsafe.Pointer {
-	slotValueOffset := unsafe.Sizeof(hashmapBucket{}) + uintptr(m.keySize)*8 + uintptr(m.valueSize)*uintptr(slot)
-	slotValue := unsafe.Add(unsafe.Pointer(bucket), slotValueOffset)
-	return slotValue
+	slotValueOffset := hashmapBucketHeaderSize + hashmapKeySlotSize(m)*8 + hashmapValueSlotSize(m)*uintptr(slot)
+	return unsafe.Add(unsafe.Pointer(bucket), slotValueOffset)
 }
 
 // Set a specified key to a given value. Grow the map if necessary.
@@ -234,9 +296,9 @@ func hashmapSet(m *hashmap, key unsafe.Pointer, value unsafe.Pointer, hash uint3
 			}
 			if bucket.tophash[i] == tophash {
 				// Could be an existing key that's the same.
-				if m.keyEqual(key, slotKey, m.keySize) {
-					// found same key, replace it
-					memcpy(slotValue, value, m.valueSize)
+				if m.keyEqual(key, hashmapSlotKeyData(m, slotKey), m.keySize) {
+					// found same key, replace the value
+					hashmapStoreValue(m, slotValue, value)
 					return
 				}
 			}
@@ -251,11 +313,45 @@ func hashmapSet(m *hashmap, key unsafe.Pointer, value unsafe.Pointer, hash uint3
 		return
 	}
 	m.count++
-	memcpy(emptySlotKey, key, m.keySize)
-	memcpy(emptySlotValue, value, m.valueSize)
+	hashmapStoreKey(m, emptySlotKey, key)
+	hashmapStoreValue(m, emptySlotValue, value)
 	*emptySlotTophash = tophash
 }
 
+// hashmapStoreKey stores a key into a bucket slot, allocating backing storage
+// if the key is indirect (first insert) or copying into it (shouldn't happen
+// for keys, but handles it correctly).
+//
+//go:inline
+func hashmapStoreKey(m *hashmap, slotKey, key unsafe.Pointer) {
+	if m.flags&hashmapFlagIndirectKey != 0 {
+		p := alloc(m.keySize, nil)
+		memcpy(p, key, m.keySize)
+		*(*unsafe.Pointer)(slotKey) = p
+	} else {
+		memcpy(slotKey, key, m.keySize)
+	}
+}
+
+// hashmapStoreValue stores a value into a bucket slot. For indirect values,
+// it allocates backing storage on first insert or copies into the existing
+// backing on overwrite.
+//
+//go:inline
+func hashmapStoreValue(m *hashmap, slotValue, value unsafe.Pointer) {
+	if m.flags&hashmapFlagIndirectValue != 0 {
+		p := *(*unsafe.Pointer)(slotValue)
+		if p == nil {
+			// First insert: allocate backing storage.
+			p = alloc(m.valueSize, nil)
+			*(*unsafe.Pointer)(slotValue) = p
+		}
+		memcpy(p, value, m.valueSize)
+	} else {
+		memcpy(slotValue, value, m.valueSize)
+	}
+}
+
 // hashmapInsertIntoNewBucket creates a new bucket, inserts the given key and
 // value into the bucket, and returns a pointer to this bucket.
 func hashmapInsertIntoNewBucket(m *hashmap, key, value unsafe.Pointer, tophash uint8) *hashmapBucket {
@@ -267,8 +363,8 @@ func hashmapInsertIntoNewBucket(m *hashmap, key, value unsafe.Pointer, tophash u
 	slotKey := hashmapSlotKey(m, bucket, 0)
 	slotValue := hashmapSlotValue(m, bucket, 0)
 	m.count++
-	memcpy(slotKey, key, m.keySize)
-	memcpy(slotValue, value, m.valueSize)
+	hashmapStoreKey(m, slotKey, key)
+	hashmapStoreValue(m, slotValue, value)
 	bucket.tophash[0] = tophash
 	return bucket
 }
@@ -331,12 +427,12 @@ func hashmapGet(m *hashmap, key, value unsafe.Pointer, valueSize uintptr, hash u
 	for bucket != nil {
 		for i := uint8(0); i < 8; i++ {
 			slotKey := hashmapSlotKey(m, bucket, i)
-			slotValue := hashmapSlotValue(m, bucket, i)
 			if bucket.tophash[i] == tophash {
 				// This could be the key we're looking for.
-				if m.keyEqual(key, slotKey, m.keySize) {
+				if m.keyEqual(key, hashmapSlotKeyData(m, slotKey), m.keySize) {
 					// Found the key, copy it.
-					memcpy(value, slotValue, m.valueSize)
+					slotValue := hashmapSlotValue(m, bucket, i)
+					memcpy(value, hashmapSlotValueData(m, slotValue), m.valueSize)
 					return true
 				}
 			}
@@ -370,13 +466,15 @@ func hashmapDelete(m *hashmap, key unsafe.Pointer, hash uint32) {
 			slotKey := hashmapSlotKey(m, bucket, i)
 			if bucket.tophash[i] == tophash {
 				// This could be the key we're looking for.
-				if m.keyEqual(key, slotKey, m.keySize) {
+				if m.keyEqual(key, hashmapSlotKeyData(m, slotKey), m.keySize) {
 					// Found the key, delete it.
 					bucket.tophash[i] = 0
-					// Zero out the key and value so garbage collector doesn't pin the allocations.
-					memzero(slotKey, m.keySize)
+					// Zero out the slot so the GC won't pin the allocations.
+					keySlotSize := hashmapKeySlotSize(m)
+					memzero(slotKey, keySlotSize)
 					slotValue := hashmapSlotValue(m, bucket, i)
-					memzero(slotValue, m.valueSize)
+					valueSlotSize := hashmapValueSlotSize(m)
+					memzero(slotValue, valueSlotSize)
 					m.count--
 					return
 				}
@@ -438,13 +536,13 @@ func hashmapNext(m *hashmap, it *hashmapIterator, key, value unsafe.Pointer) boo
 
 		// Found a key.
 		slotKey := hashmapSlotKey(m, it.bucket, it.bucketIndex)
-		memcpy(key, slotKey, m.keySize)
+		memcpy(key, hashmapSlotKeyData(m, slotKey), m.keySize)
 
 		if it.buckets == m.buckets {
 			// Our view of the buckets is the same as the parent map.
 			// Just copy the value we have
 			slotValue := hashmapSlotValue(m, it.bucket, it.bucketIndex)
-			memcpy(value, slotValue, m.valueSize)
+			memcpy(value, hashmapSlotValueData(m, slotValue), m.valueSize)
 			it.bucketIndex++
 		} else {
 			it.bucketIndex++
@@ -491,6 +589,112 @@ func hashmapBinaryDelete(m *hashmap, key unsafe.Pointer) {
 	hashmapDelete(m, key, hash)
 }
 
+// Hashmap with compiler-generated key hash/equal functions.
+// Unlike the binary path (which uses hash32/memequal), these use the
+// type-specific keyHash and keyEqual function pointers stored in the hashmap
+// struct. This is used for composite key types (e.g. structs containing
+// strings) where the compiler generates specialized hash/equal functions.
+
+func hashmapGenericSet(m *hashmap, key, value unsafe.Pointer) {
+	if m == nil {
+		nilMapPanic()
+	}
+	hash := m.keyHash(key, m.keySize, m.seed)
+	hashmapSet(m, key, value, hash)
+}
+
+func hashmapGenericGet(m *hashmap, key, value unsafe.Pointer, valueSize uintptr) bool {
+	if m == nil {
+		memzero(value, uintptr(valueSize))
+		return false
+	}
+	hash := m.keyHash(key, m.keySize, m.seed)
+	return hashmapGet(m, key, value, valueSize, hash)
+}
+
+func hashmapGenericDelete(m *hashmap, key unsafe.Pointer) {
+	if m == nil {
+		return
+	}
+	hash := m.keyHash(key, m.keySize, m.seed)
+	hashmapDelete(m, key, hash)
+}
+
+// hashmapMakeGeneric creates a new hashmap with compiler-provided hash and
+// equal functions. This avoids the interface/reflection path for composite
+// key types like structs containing strings.
+func hashmapMakeGeneric(keySize, valueSize uintptr, sizeHint uintptr,
+	keyHash func(key unsafe.Pointer, size, seed uintptr) uint32,
+	keyEqual func(x, y unsafe.Pointer, n uintptr) bool) *hashmap {
+	bucketBits := uint8(0)
+	for hashmapHasSpaceToGrow(bucketBits) && hashmapOverLoadFactor(sizeHint, bucketBits) {
+		bucketBits++
+	}
+
+	var flags uint8
+	keySlotSize := keySize
+	if keySize > hashmapMaxKeySize {
+		flags |= hashmapFlagIndirectKey
+		keySlotSize = unsafe.Sizeof(unsafe.Pointer(nil))
+	}
+	valueSlotSize := valueSize
+	if valueSize > hashmapMaxValueSize {
+		flags |= hashmapFlagIndirectValue
+		valueSlotSize = unsafe.Sizeof(unsafe.Pointer(nil))
+	}
+
+	bucketBufSize := hashmapBucketHeaderSize + keySlotSize*8 + valueSlotSize*8
+	buckets := alloc(bucketBufSize*(1<<bucketBits), nil)
+
+	return &hashmap{
+		buckets:       buckets,
+		seed:          uintptr(fastrand()),
+		keySize:       keySize,
+		valueSize:     valueSize,
+		keySlotSize:   keySlotSize,
+		valueSlotSize: valueSlotSize,
+		bucketBits:    bucketBits,
+		flags:         flags,
+		keyEqual:      keyEqual,
+		keyHash:       keyHash,
+	}
+}
+
+// hashmapMakeReflect creates a hashmap for reflect.MakeMapWithSize using
+// closures that reconstruct interface{} values from raw key bytes,
+// delegating to hashmapInterfaceHash for hashing and == for equality.
+func hashmapMakeReflect(keySize, valueSize, sizeHint uintptr, keyType unsafe.Pointer) *hashmap {
+	t := (*reflectlite.RawType)(keyType)
+	if t.Kind() == reflectlite.Interface {
+		// Interface keys are already stored as interface values in the
+		// bucket; use the existing interface hash/equal directly.
+		return hashmapMakeGeneric(keySize, valueSize, sizeHint,
+			hashmapInterfacePtrHash, hashmapInterfaceEqual)
+	}
+	keyHash := func(key unsafe.Pointer, size, seed uintptr) uint32 {
+		return hashmapInterfaceHash(rawToInterface(t, key), seed)
+	}
+	keyEqual := func(x, y unsafe.Pointer, n uintptr) bool {
+		return rawToInterface(t, x) == rawToInterface(t, y)
+	}
+	return hashmapMakeGeneric(keySize, valueSize, sizeHint, keyHash, keyEqual)
+}
+
+// rawToInterface reconstructs an interface{} from raw bytes at ptr.
+func rawToInterface(t *reflectlite.RawType, ptr unsafe.Pointer) interface{} {
+	var val unsafe.Pointer
+	if t.Size() <= unsafe.Sizeof(uintptr(0)) {
+		val = reflectliteLoadSmallValue(ptr, t.Size())
+	} else {
+		val = ptr
+	}
+	i := composeInterface(unsafe.Pointer(t), val)
+	return *(*interface{})(unsafe.Pointer(&i))
+}
+
+//go:linkname reflectliteLoadSmallValue internal/reflectlite.loadSmallValue
+func reflectliteLoadSmallValue(ptr unsafe.Pointer, size uintptr) unsafe.Pointer
+
 // Hashmap with string keys (a common case).
 
 func hashmapStringEqual(x, y unsafe.Pointer, n uintptr) bool {
@@ -626,28 +830,3 @@ func hashmapInterfacePtrHash(iptr unsafe.Pointer, size uintptr, seed uintptr) ui
 func hashmapInterfaceEqual(x, y unsafe.Pointer, n uintptr) bool {
 	return *(*interface{})(x) == *(*interface{})(y)
 }
-
-func hashmapInterfaceSet(m *hashmap, key interface{}, value unsafe.Pointer) {
-	if m == nil {
-		nilMapPanic()
-	}
-	hash := hashmapInterfaceHash(key, m.seed)
-	hashmapSet(m, unsafe.Pointer(&key), value, hash)
-}
-
-func hashmapInterfaceGet(m *hashmap, key interface{}, value unsafe.Pointer, valueSize uintptr) bool {
-	if m == nil {
-		memzero(value, uintptr(valueSize))
-		return false
-	}
-	hash := hashmapInterfaceHash(key, m.seed)
-	return hashmapGet(m, unsafe.Pointer(&key), value, valueSize, hash)
-}
-
-func hashmapInterfaceDelete(m *hashmap, key interface{}) {
-	if m == nil {
-		return
-	}
-	hash := hashmapInterfaceHash(key, m.seed)
-	hashmapDelete(m, unsafe.Pointer(&key), hash)
-}

src/tinygo/runtime.go

@@ -13,5 +13,4 @@ type HashmapAlgorithm uint8
 const (
 	HashmapAlgorithmBinary HashmapAlgorithm = iota
 	HashmapAlgorithmString
-	HashmapAlgorithmInterface
 )