runtime: require explicit GC layouts

src/runtime/arch_tinygowasm_malloc.go

@@ -2,7 +2,10 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"internal/gclayout"
+	"unsafe"
+)
 
 // The below functions override the default allocator of wasi-libc. This ensures
 // code linked from other languages can allocate memory without colliding with
@@ -21,7 +24,7 @@ func libc_malloc(size uintptr) unsafe.Pointer {
 	if size == 0 {
 		return nil
 	}
-	ptr := alloc(size, nil)
+	ptr := alloc(size, gclayout.NoPtrs.AsPtr())
 	allocs[(*byte)(ptr)] = size
 	return ptr
 }
@@ -54,7 +57,7 @@ func libc_realloc(oldPtr unsafe.Pointer, size uintptr) unsafe.Pointer {
 	// It's hard to optimize this to expand the current buffer with our GC, but
 	// it is theoretically possible. For now, just always allocate fresh.
 	// TODO: we could skip this if the new allocation is smaller than the old.
-	ptr := alloc(size, nil)
+	ptr := alloc(size, gclayout.NoPtrs.AsPtr())
 
 	if oldPtr != nil {
 		if oldSize, ok := allocs[(*byte)(oldPtr)]; ok {

src/runtime/baremetal.go

@@ -3,6 +3,7 @@
 package runtime
 
 import (
+	"internal/gclayout"
 	"sync/atomic"
 	"unsafe"
 )
@@ -11,7 +12,7 @@ import (
 func libc_malloc(size uintptr) unsafe.Pointer {
 	// Note: this zeroes the returned buffer which is not necessary.
 	// The same goes for bytealg.MakeNoZero.
-	return alloc(size, nil)
+	return alloc(size, gclayout.NoPtrs.AsPtr())
 }
 
 //export calloc

src/runtime/chan.go

@@ -137,11 +137,11 @@ type chanSelectState struct {
 	value unsafe.Pointer
 }
 
-func chanMake(elementSize uintptr, bufSize uintptr) *channel {
+func chanMake(elementSize uintptr, bufSize uintptr, elementLayout unsafe.Pointer) *channel {
 	return &channel{
 		elementSize: elementSize,
 		bufCap:      bufSize,
-		buf:         alloc(elementSize*bufSize, nil),
+		buf:         alloc(elementSize*bufSize, elementLayout),
 	}
 }
 

src/runtime/gc_blocks.go

@@ -31,6 +31,7 @@ package runtime
 // Moss.
 
 import (
+	"internal/gclayout"
 	"internal/reflectlite"
 	"internal/task"
 	"runtime/interrupt"
@@ -501,7 +502,7 @@ func alloc(size uintptr, layout unsafe.Pointer) unsafe.Pointer {
 
 func realloc(ptr unsafe.Pointer, size uintptr) unsafe.Pointer {
 	if ptr == nil {
-		return alloc(size, nil)
+		return alloc(size, gclayout.NoPtrs.AsPtr())
 	}
 
 	// Find the first block of the original allocation.
@@ -526,7 +527,7 @@ func realloc(ptr unsafe.Pointer, size uintptr) unsafe.Pointer {
 	}
 
 	// Create a new allocation and copy the old data.
-	newAlloc := alloc(size, nil)
+	newAlloc := alloc(size, gclayout.NoPtrs.AsPtr())
 	memcpy(newAlloc, ptr, oldSize)
 	free(ptr)
 

src/runtime/gc_leaking.go

@@ -7,6 +7,7 @@ package runtime
 // may be the only memory allocator possible.
 
 import (
+	"internal/gclayout"
 	"internal/task"
 	"sync/atomic"
 	"unsafe"
@@ -69,7 +70,7 @@ func alloc(size uintptr, layout unsafe.Pointer) unsafe.Pointer {
 }
 
 func realloc(ptr unsafe.Pointer, size uintptr) unsafe.Pointer {
-	newAlloc := alloc(size, nil)
+	newAlloc := alloc(size, gclayout.NoPtrs.AsPtr())
 	if ptr == nil {
 		return newAlloc
 	}

src/runtime/gc_precise.go

@@ -55,7 +55,10 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"internal/gclayout"
+	"unsafe"
+)
 
 const sizeFieldBits = 4 + (unsafe.Sizeof(uintptr(0)) / 4)
 
@@ -76,9 +79,7 @@ func (layout gcLayout) pointerFree() bool {
 // The length is rounded down to a multiple of the element size.
 func (layout gcLayout) scan(start, len uintptr) {
 	switch {
-	case layout == 0:
-		// This is an unknown layout.
-		// Scan conservatively.
+	case layout == gcLayout(gclayout.Conservative):
 		// NOTE: This is *NOT* equivalent to a slice of pointers on AVR.
 		scanConservative(start, len)
 

src/runtime/hashmap.go

@@ -14,6 +14,7 @@ import (
 // The underlying hashmap structure for Go.
 type hashmap struct {
 	buckets       unsafe.Pointer // pointer to array of buckets
+	typeInfo      *hashmapTypeInfo
 	seed          uintptr
 	count         uintptr
 	keySize       uintptr
@@ -26,6 +27,17 @@ type hashmap struct {
 	keyHash       func(key unsafe.Pointer, size, seed uintptr) uint32
 }
 
+type hashmapTypeInfo struct {
+	keyLayout    unsafe.Pointer
+	valueLayout  unsafe.Pointer
+	bucketLayout unsafe.Pointer
+}
+
+//go:inline
+func hashmapType(m *hashmap) *hashmapTypeInfo {
+	return m.typeInfo
+}
+
 const (
 	hashmapMaxKeySize   = 128
 	hashmapMaxValueSize = 128
@@ -113,7 +125,7 @@ func hashmapTopHash(hash uint32) uint8 {
 }
 
 // Create a new hashmap with the given keySize and valueSize.
-func hashmapMake(keySize, valueSize uintptr, sizeHint uintptr, alg uint8) *hashmap {
+func hashmapMake(keySize, valueSize uintptr, sizeHint uintptr, typeInfo unsafe.Pointer, alg uint8) *hashmap {
 	bucketBits := uint8(0)
 	for hashmapHasSpaceToGrow(bucketBits) && hashmapOverLoadFactor(sizeHint, bucketBits) {
 		bucketBits++
@@ -132,13 +144,14 @@ func hashmapMake(keySize, valueSize uintptr, sizeHint uintptr, alg uint8) *hashm
 	}
 
 	bucketBufSize := hashmapBucketHeaderSize + keySlotSize*8 + valueSlotSize*8
-	buckets := alloc(bucketBufSize*(1<<bucketBits), nil)
+	buckets := alloc(bucketBufSize*(1<<bucketBits), (*hashmapTypeInfo)(typeInfo).bucketLayout)
 
 	keyHash := hashmapKeyHashAlg(tinygo.HashmapAlgorithm(alg))
 	keyEqual := hashmapKeyEqualAlg(tinygo.HashmapAlgorithm(alg))
 
 	return &hashmap{
 		buckets:       buckets,
+		typeInfo:      (*hashmapTypeInfo)(typeInfo),
 		seed:          uintptr(fastrand()),
 		keySize:       keySize,
 		valueSize:     valueSize,
@@ -325,7 +338,7 @@ func hashmapSet(m *hashmap, key unsafe.Pointer, value unsafe.Pointer, hash uint3
 //go:inline
 func hashmapStoreKey(m *hashmap, slotKey, key unsafe.Pointer) {
 	if m.flags&hashmapFlagIndirectKey != 0 {
-		p := alloc(m.keySize, nil)
+		p := alloc(m.keySize, hashmapType(m).keyLayout)
 		memcpy(p, key, m.keySize)
 		*(*unsafe.Pointer)(slotKey) = p
 	} else {
@@ -343,7 +356,7 @@ func hashmapStoreValue(m *hashmap, slotValue, value unsafe.Pointer) {
 		p := *(*unsafe.Pointer)(slotValue)
 		if p == nil {
 			// First insert: allocate backing storage.
-			p = alloc(m.valueSize, nil)
+			p = alloc(m.valueSize, hashmapType(m).valueLayout)
 			*(*unsafe.Pointer)(slotValue) = p
 		}
 		memcpy(p, value, m.valueSize)
@@ -356,7 +369,7 @@ func hashmapStoreValue(m *hashmap, slotValue, value unsafe.Pointer) {
 // value into the bucket, and returns a pointer to this bucket.
 func hashmapInsertIntoNewBucket(m *hashmap, key, value unsafe.Pointer, tophash uint8) *hashmapBucket {
 	bucketBufSize := hashmapBucketSize(m)
-	bucketBuf := alloc(bucketBufSize, nil)
+	bucketBuf := alloc(bucketBufSize, hashmapType(m).bucketLayout)
 	bucket := (*hashmapBucket)(bucketBuf)
 
 	// Insert into the first slot, which is empty as it has just been allocated.
@@ -392,13 +405,13 @@ func hashmapCopy(m *hashmap, sizeBits uint8) hashmap {
 	n.bucketBits = sizeBits
 	numBuckets := uintptr(1) << n.bucketBits
 	bucketBufSize := hashmapBucketSize(m)
-	n.buckets = alloc(bucketBufSize*numBuckets, nil)
+	n.buckets = alloc(bucketBufSize*numBuckets, hashmapType(m).bucketLayout)
 
 	// use a hashmap iterator to go through the old map
 	var it hashmapIterator
 
-	var key = alloc(m.keySize, nil)
-	var value = alloc(m.valueSize, nil)
+	var key = alloc(m.keySize, hashmapType(m).keyLayout)
+	var value = alloc(m.valueSize, hashmapType(m).valueLayout)
 
 	for hashmapNext(m, &it, key, value) {
 		h := n.keyHash(key, uintptr(n.keySize), n.seed)
@@ -624,6 +637,7 @@ func hashmapGenericDelete(m *hashmap, key unsafe.Pointer) {
 // equal functions. This avoids the interface/reflection path for composite
 // key types like structs containing strings.
 func hashmapMakeGeneric(keySize, valueSize uintptr, sizeHint uintptr,
+	typeInfo unsafe.Pointer,
 	keyHash func(key unsafe.Pointer, size, seed uintptr) uint32,
 	keyEqual func(x, y unsafe.Pointer, n uintptr) bool) *hashmap {
 	bucketBits := uint8(0)
@@ -644,10 +658,11 @@ func hashmapMakeGeneric(keySize, valueSize uintptr, sizeHint uintptr,
 	}
 
 	bucketBufSize := hashmapBucketHeaderSize + keySlotSize*8 + valueSlotSize*8
-	buckets := alloc(bucketBufSize*(1<<bucketBits), nil)
+	buckets := alloc(bucketBufSize*(1<<bucketBits), (*hashmapTypeInfo)(typeInfo).bucketLayout)
 
 	return &hashmap{
 		buckets:       buckets,
+		typeInfo:      (*hashmapTypeInfo)(typeInfo),
 		seed:          uintptr(fastrand()),
 		keySize:       keySize,
 		valueSize:     valueSize,
@@ -663,12 +678,12 @@ func hashmapMakeGeneric(keySize, valueSize uintptr, sizeHint uintptr,
 // 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 {
+func hashmapMakeReflect(keySize, valueSize, sizeHint uintptr, typeInfo, 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,
+		return hashmapMakeGeneric(keySize, valueSize, sizeHint, typeInfo,
 			hashmapInterfacePtrHash, hashmapInterfaceEqual)
 	}
 	keyHash := func(key unsafe.Pointer, size, seed uintptr) uint32 {
@@ -677,7 +692,7 @@ func hashmapMakeReflect(keySize, valueSize, sizeHint uintptr, keyType unsafe.Poi
 	keyEqual := func(x, y unsafe.Pointer, n uintptr) bool {
 		return rawToInterface(t, x) == rawToInterface(t, y)
 	}
-	return hashmapMakeGeneric(keySize, valueSize, sizeHint, keyHash, keyEqual)
+	return hashmapMakeGeneric(keySize, valueSize, sizeHint, typeInfo, keyHash, keyEqual)
 }
 
 // rawToInterface reconstructs an interface{} from raw bytes at ptr.