1 files changed, 78 insertions, 43 deletions
diff --git a/src/runtime/alg.go b/src/runtime/alg.go
index 57306f81d9..935d45d503 100644
--- a/src/runtime/alg.go
+++ b/src/runtime/alg.go
@@ -34,17 +34,6 @@ const (
 	alg_max
 )
 
-// typeAlg is also copied/used in reflect/type.go.
-// keep them in sync.
-type typeAlg struct {
-	// function for hashing objects of this type
-	// (ptr to object, seed) -> hash
-	hash func(unsafe.Pointer, uintptr) uintptr
-	// function for comparing objects of this type
-	// (ptr to object A, ptr to object B) -> ==?
-	equal func(unsafe.Pointer, unsafe.Pointer) bool
-}
-
 func memhash0(p unsafe.Pointer, h uintptr) uintptr {
 	return h
 }
@@ -68,23 +57,9 @@ func memhash_varlen(p unsafe.Pointer, h uintptr) uintptr {
 	return memhash(p, h, size)
 }
 
-var algarray = [alg_max]typeAlg{
-	alg_NOEQ:     {nil, nil},
-	alg_MEM0:     {memhash0, memequal0},
-	alg_MEM8:     {memhash8, memequal8},
-	alg_MEM16:    {memhash16, memequal16},
-	alg_MEM32:    {memhash32, memequal32},
-	alg_MEM64:    {memhash64, memequal64},
-	alg_MEM128:   {memhash128, memequal128},
-	alg_STRING:   {strhash, strequal},
-	alg_INTER:    {interhash, interequal},
-	alg_NILINTER: {nilinterhash, nilinterequal},
-	alg_FLOAT32:  {f32hash, f32equal},
-	alg_FLOAT64:  {f64hash, f64equal},
-	alg_CPLX64:   {c64hash, c64equal},
-	alg_CPLX128:  {c128hash, c128equal},
-}
-
+// runtime variable to check if the processor we're running on
+// actually supports the instructions used by the AES-based
+// hash implementation.
 var useAeshash bool
 
 // in asm_*.s
@@ -144,14 +119,17 @@ func interhash(p unsafe.Pointer, h uintptr) uintptr {
 		return h
 	}
 	t := tab._type
-	fn := t.alg.hash
-	if fn == nil {
+	if t.equal == nil {
+		// Check hashability here. We could do this check inside
+		// typehash, but we want to report the topmost type in
+		// the error text (e.g. in a struct with a field of slice type
+		// we want to report the struct, not the slice).
 		panic(errorString("hash of unhashable type " + t.string()))
 	}
 	if isDirectIface(t) {
-		return c1 * fn(unsafe.Pointer(&a.data), h^c0)
+		return c1 * typehash(t, unsafe.Pointer(&a.data), h^c0)
 	} else {
-		return c1 * fn(a.data, h^c0)
+		return c1 * typehash(t, a.data, h^c0)
 	}
 }
 
@@ -161,15 +139,72 @@ func nilinterhash(p unsafe.Pointer, h uintptr) uintptr {
 	if t == nil {
 		return h
 	}
-	fn := t.alg.hash
-	if fn == nil {
+	if t.equal == nil {
+		// See comment in interhash above.
 		panic(errorString("hash of unhashable type " + t.string()))
 	}
 	if isDirectIface(t) {
-		return c1 * fn(unsafe.Pointer(&a.data), h^c0)
+		return c1 * typehash(t, unsafe.Pointer(&a.data), h^c0)
 	} else {
-		return c1 * fn(a.data, h^c0)
+		return c1 * typehash(t, a.data, h^c0)
+	}
+}
+
+// typehash computes the hash of the object of type t at address p.
+// h is the seed.
+// This function is seldom used. Most maps use for hashing either
+// fixed functions (e.g. f32hash) or compiler-generated functions
+// (e.g. for a type like struct { x, y string }). This implementation
+// is slower but more general and is used for hashing interface types
+// (called from interhash or nilinterhash, above) or for hashing in
+// maps generated by reflect.MapOf (reflect_typehash, below).
+func typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr {
+	if t.tflag&tflagRegularMemory != 0 {
+		return memhash(p, h, t.size)
 	}
+	switch t.kind & kindMask {
+	case kindFloat32:
+		return f32hash(p, h)
+	case kindFloat64:
+		return f64hash(p, h)
+	case kindComplex64:
+		return c64hash(p, h)
+	case kindComplex128:
+		return c128hash(p, h)
+	case kindString:
+		return strhash(p, h)
+	case kindInterface:
+		i := (*interfacetype)(unsafe.Pointer(t))
+		if len(i.mhdr) == 0 {
+			return nilinterhash(p, h)
+		}
+		return interhash(p, h)
+	case kindArray:
+		a := (*arraytype)(unsafe.Pointer(t))
+		for i := uintptr(0); i < a.len; i++ {
+			h = typehash(a.elem, add(p, i*a.elem.size), h)
+		}
+		return h
+	case kindStruct:
+		s := (*structtype)(unsafe.Pointer(t))
+		for _, f := range s.fields {
+			// TODO: maybe we could hash several contiguous fields all at once.
+			if f.name.isBlank() {
+				continue
+			}
+			h = typehash(f.typ, add(p, f.offset()), h)
+		}
+		return h
+	default:
+		// Should never happen, as typehash should only be called
+		// with comparable types.
+		panic(errorString("hash of unhashable type " + t.string()))
+	}
+}
+
+//go:linkname reflect_typehash reflect.typehash
+func reflect_typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr {
+	return typehash(t, p, h)
 }
 
 func memequal0(p, q unsafe.Pointer) bool {
@@ -219,7 +254,7 @@ func efaceeq(t *_type, x, y unsafe.Pointer) bool {
 	if t == nil {
 		return true
 	}
-	eq := t.alg.equal
+	eq := t.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + t.string()))
 	}
@@ -236,7 +271,7 @@ func ifaceeq(tab *itab, x, y unsafe.Pointer) bool {
 		return true
 	}
 	t := tab._type
-	eq := t.alg.equal
+	eq := t.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + t.string()))
 	}
@@ -249,7 +284,7 @@ func ifaceeq(tab *itab, x, y unsafe.Pointer) bool {
 
 // Testing adapters for hash quality tests (see hash_test.go)
 func stringHash(s string, seed uintptr) uintptr {
-	return algarray[alg_STRING].hash(noescape(unsafe.Pointer(&s)), seed)
+	return strhash(noescape(unsafe.Pointer(&s)), seed)
 }
 
 func bytesHash(b []byte, seed uintptr) uintptr {
@@ -258,21 +293,21 @@ func bytesHash(b []byte, seed uintptr) uintptr {
 }
 
 func int32Hash(i uint32, seed uintptr) uintptr {
-	return algarray[alg_MEM32].hash(noescape(unsafe.Pointer(&i)), seed)
+	return memhash32(noescape(unsafe.Pointer(&i)), seed)
 }
 
 func int64Hash(i uint64, seed uintptr) uintptr {
-	return algarray[alg_MEM64].hash(noescape(unsafe.Pointer(&i)), seed)
+	return memhash64(noescape(unsafe.Pointer(&i)), seed)
 }
 
 func efaceHash(i interface{}, seed uintptr) uintptr {
-	return algarray[alg_NILINTER].hash(noescape(unsafe.Pointer(&i)), seed)
+	return nilinterhash(noescape(unsafe.Pointer(&i)), seed)
 }
 
 func ifaceHash(i interface {
 	F()
 }, seed uintptr) uintptr {
-	return algarray[alg_INTER].hash(noescape(unsafe.Pointer(&i)), seed)
+	return interhash(noescape(unsafe.Pointer(&i)), seed)
 }
 
 const hashRandomBytes = sys.PtrSize / 4 * 64