Go patch committed: Generate hash functions only for map keys

Message ID CAOyqgcUs64mQoOVbGbZCP6j-DJi-B2ocdf7AnEmYfk4JZwYB_w@mail.gmail.com
State New
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  • Go patch committed: Generate hash functions only for map keys
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Commit Message

Ian Lance Taylor Jan. 2, 2020, 9:55 p.m.
This patch to the Go frontend and libgo changes the compiler to only
generate hash functions for types used as map keys.

Right now we generate hash functions for all types, just in case they
are used as map keys. That's a lot of wasted effort and binary size
for types which will never be used as a map key. Instead, generate
hash functions only for types that we know are map keys.

Just doing that is a bit too simple, since maps with an interface type
as a key might have to hash any concrete key type that implements that
interface.  So for that case, implement hashing of such types at
runtime (instead of with generated code). It will be slower, but only
for maps with interface types as keys, and maybe only a bit slower as
the aeshash time probably dominates the dispatch time.

Reorg where we keep the equals and hash functions.  Move the hash
function from the key type to the map type, saving a field in every
non-map type.  That leaves only one function in the alg structure, so
get rid of that and just keep the equal function in the type
descriptor itself.

While we're here, reorganize the rtype struct to more closely match
the gc version.

This is the gofrontend version of https://golang.org/cl/191198.

Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu.  Committed
to mainline.

Ian

Patch

Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE	(revision 279847)
+++ gcc/go/gofrontend/MERGE	(working copy)
@@ -1,4 +1,4 @@ 
-b5c950fb98042fe434edca0c2403234692f25cd4
+9163fa28b89222cd851c0d24bd6a1384d1379c55
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: gcc/go/gofrontend/gogo.cc
===================================================================
--- gcc/go/gofrontend/gogo.cc	(revision 279847)
+++ gcc/go/gofrontend/gogo.cc	(working copy)
@@ -2722,7 +2722,7 @@  Gogo::clear_file_scope()
 // parse tree is lowered.
 
 void
-Gogo::queue_hash_function(Type* type, Named_type* name, int64_t size,
+Gogo::queue_hash_function(Type* type, int64_t size,
 			  const std::string& hash_name,
 			  Function_type* hash_fntype)
 {
@@ -2730,7 +2730,7 @@  Gogo::queue_hash_function(Type* type, Na
   go_assert(!this->in_global_scope());
   Specific_type_function::Specific_type_function_kind kind =
     Specific_type_function::SPECIFIC_HASH;
-  Specific_type_function* tsf = new Specific_type_function(type, name, size,
+  Specific_type_function* tsf = new Specific_type_function(type, NULL, size,
 							   kind, hash_name,
 							   hash_fntype);
   this->specific_type_functions_.push_back(tsf);
@@ -2783,10 +2783,7 @@  Specific_type_functions::type(Type* t)
 	if (nt->is_alias())
 	  return TRAVERSE_CONTINUE;
 	if (t->needs_specific_type_functions(this->gogo_))
-	  {
-	    t->equal_function(this->gogo_, nt, NULL);
-	    t->hash_function(this->gogo_, nt, NULL);
-	  }
+	  t->equal_function(this->gogo_, nt, NULL);
 
 	// If this is a struct type, we don't want to make functions
 	// for the unnamed struct.
@@ -2820,10 +2817,15 @@  Specific_type_functions::type(Type* t)
     case Type::TYPE_STRUCT:
     case Type::TYPE_ARRAY:
       if (t->needs_specific_type_functions(this->gogo_))
-	{
-	  t->equal_function(this->gogo_, NULL, NULL);
-	  t->hash_function(this->gogo_, NULL, NULL);
-	}
+	t->equal_function(this->gogo_, NULL, NULL);
+      break;
+
+    case Type::TYPE_MAP:
+      {
+	Type* key_type = t->map_type()->key_type();
+	if (key_type->needs_specific_type_functions(this->gogo_))
+	  key_type->hash_function(this->gogo_, NULL);
+      }
       break;
 
     default:
@@ -2846,8 +2848,8 @@  Gogo::write_specific_type_functions()
       Specific_type_function* tsf = this->specific_type_functions_.back();
       this->specific_type_functions_.pop_back();
       if (tsf->kind == Specific_type_function::SPECIFIC_HASH)
-	tsf->type->write_hash_function(this, tsf->name, tsf->size,
-				       tsf->fnname, tsf->fntype);
+	tsf->type->write_hash_function(this, tsf->size, tsf->fnname,
+				       tsf->fntype);
       else
 	tsf->type->write_equal_function(this, tsf->name, tsf->size,
 					tsf->fnname, tsf->fntype);
Index: gcc/go/gofrontend/gogo.h
===================================================================
--- gcc/go/gofrontend/gogo.h	(revision 279847)
+++ gcc/go/gofrontend/gogo.h	(working copy)
@@ -602,8 +602,7 @@  class Gogo
   // is used when a type-specific hash function is needed when not at
   // top level.
   void
-  queue_hash_function(Type* type, Named_type* name, int64_t size,
-		      const std::string& hash_name,
+  queue_hash_function(Type* type, int64_t size, const std::string& hash_name,
 		      Function_type* hash_fntype);
 
   // Queue up a type-specific equal function to be written out.  This
@@ -879,7 +878,7 @@  class Gogo
 
   // Return the name of the hash function for TYPE.
   std::string
-  hash_function_name(const Type*, const Named_type*);
+  hash_function_name(const Type*);
 
   // Return the name of the equal function for TYPE.
   std::string
Index: gcc/go/gofrontend/names.cc
===================================================================
--- gcc/go/gofrontend/names.cc	(revision 279847)
+++ gcc/go/gofrontend/names.cc	(working copy)
@@ -287,16 +287,12 @@  Gogo::stub_method_name(const Package* pa
   return ret;
 }
 
-// Return the name of the hash function for TYPE.  If NAME is not NULL
-// it is the name of the type.
+// Return the name of the hash function for TYPE.
 
 std::string
-Gogo::hash_function_name(const Type* type, const Named_type* name)
+Gogo::hash_function_name(const Type* type)
 {
-  const Type* rtype = type;
-  if (name != NULL)
-    rtype = name;
-  std::string tname = rtype->mangled_name(this);
+  std::string tname = type->mangled_name(this);
   return tname + "..hash";
 }
 
Index: gcc/go/gofrontend/types.cc
===================================================================
--- gcc/go/gofrontend/types.cc	(revision 279847)
+++ gcc/go/gofrontend/types.cc	(working copy)
@@ -1540,6 +1540,11 @@  Type::convert_builtin_named_types(Gogo*
     }
 }
 
+// Values to store in the tflag field of a type descriptor.  This must
+// match the definitions in libgo/go/runtime/type.go.
+
+const int TFLAG_REGULAR_MEMORY = 1 << 3;
+
 // Return the type of a type descriptor.  We should really tie this to
 // runtime.Type rather than copying it.  This must match the struct "_type"
 // declared in libgo/go/runtime/type.go.
@@ -1566,21 +1571,11 @@  Type::make_type_descriptor_type()
       Type* void_type = Type::make_void_type();
       Type* unsafe_pointer_type = Type::make_pointer_type(void_type);
 
-      Typed_identifier_list *params = new Typed_identifier_list();
-      params->push_back(Typed_identifier("key", unsafe_pointer_type, bloc));
-      params->push_back(Typed_identifier("seed", uintptr_type, bloc));
-
-      Typed_identifier_list* results = new Typed_identifier_list();
-      results->push_back(Typed_identifier("", uintptr_type, bloc));
-
-      Type* hash_fntype = Type::make_function_type(NULL, params, results,
-						   bloc);
-
-      params = new Typed_identifier_list();
+      Typed_identifier_list* params = new Typed_identifier_list();
       params->push_back(Typed_identifier("key1", unsafe_pointer_type, bloc));
       params->push_back(Typed_identifier("key2", unsafe_pointer_type, bloc));
 
-      results = new Typed_identifier_list();
+      Typed_identifier_list* results = new Typed_identifier_list();
       results->push_back(Typed_identifier("", Type::lookup_bool_type(), bloc));
 
       Type* equal_fntype = Type::make_function_type(NULL, params, results,
@@ -1624,11 +1619,11 @@  Type::make_type_descriptor_type()
 				       "size", uintptr_type,
 				       "ptrdata", uintptr_type,
 				       "hash", uint32_type,
-				       "kind", uint8_type,
+				       "tflag", uint8_type,
 				       "align", uint8_type,
 				       "fieldAlign", uint8_type,
-				       "hashfn", hash_fntype,
-				       "equalfn", equal_fntype,
+				       "kind", uint8_type,
+				       "equal", equal_fntype,
 				       "gcdata", pointer_uint8_type,
 				       "string", pointer_string_type,
 				       "", pointer_uncommon_type,
@@ -1741,18 +1736,13 @@  Type::needs_specific_type_functions(Gogo
 }
 
 // Return the runtime function that computes the hash of this type.
-// If NAME is not NULL it is the name of this type.  HASH_FNTYPE is
-// the type of the hash function function, for convenience; it may be
-// NULL.  This returns NULL if the type is not comparable.
+// HASH_FNTYPE is the type of the hash function function, for
+// convenience; it may be NULL.  This returns NULL if the type is not
+// comparable.
 
 Named_object*
-Type::hash_function(Gogo* gogo, Named_type* name, Function_type* hash_fntype)
+Type::hash_function(Gogo* gogo, Function_type* hash_fntype)
 {
-  // If the unaliased type is not a named type, then the type does not
-  // have a name after all.
-  if (name != NULL)
-    name = name->unalias()->named_type();
-
   if (!this->is_comparable())
     return NULL;
 
@@ -1803,7 +1793,7 @@  Type::hash_function(Gogo* gogo, Named_ty
 	  // We don't have a built-in function for a type of this
 	  // size.  Build a function to use that calls the generic
 	  // hash functions for identity, passing the size.
-	  return this->build_hash_function(gogo, name, size, hash_fntype);
+	  return this->build_hash_function(gogo, size, hash_fntype);
 	}
     }
   else
@@ -1861,7 +1851,7 @@  Type::hash_function(Gogo* gogo, Named_ty
 	  // This is a struct which can not be compared using a simple
 	  // identity function.  We need to build a function to
 	  // compute the hash.
-	  return this->build_hash_function(gogo, name, -1, hash_fntype);
+	  return this->build_hash_function(gogo, -1, hash_fntype);
 
 	case Type::TYPE_ARRAY:
 	  if (this->is_slice_type())
@@ -1875,7 +1865,7 @@  Type::hash_function(Gogo* gogo, Named_ty
 	      // This is an array which can not be compared using a
 	      // simple identity function.  We need to build a
 	      // function to compute the hash.
-	      return this->build_hash_function(gogo, name, -1, hash_fntype);
+	      return this->build_hash_function(gogo, -1, hash_fntype);
 	    }
 	  break;
 
@@ -1895,7 +1885,6 @@  Type::hash_function(Gogo* gogo, Named_ty
 	}
     }
 
-
   Location bloc = Linemap::predeclared_location();
   Named_object *hash_fn = Named_object::make_function_declaration(hash_fnname,
 								  NULL,
@@ -1913,12 +1902,20 @@  Type::Type_function Type::type_hash_func
 // this is a struct or array type that cannot use an identity
 // comparison.  Otherwise, it is a type that uses an identity
 // comparison but is not one of the standard supported sizes.
+//
+// Unlike an equality function, hash functions are not in type
+// descriptors, so we can't assume that a named type has defined a
+// hash function in the package that defines the type.  So hash
+// functions are always defined locally.  FIXME: It would be better to
+// define hash functions with comdat linkage so that duplicate hash
+// functions can be coalesced at link time.
 
 Named_object*
-Type::build_hash_function(Gogo* gogo, Named_type* name, int64_t size,
-			  Function_type* hash_fntype)
+Type::build_hash_function(Gogo* gogo, int64_t size, Function_type* hash_fntype)
 {
-  std::pair<Type*, Named_object*> val(name != NULL ? name : this, NULL);
+  Type* type = this->base();
+
+  std::pair<Type*, Named_object*> val(type, NULL);
   std::pair<Type_function::iterator, bool> ins =
     Type::type_hash_functions_table.insert(val);
   if (!ins.second)
@@ -1927,30 +1924,19 @@  Type::build_hash_function(Gogo* gogo, Na
       return ins.first->second;
     }
 
-  std::string hash_name = gogo->hash_function_name(this, name);
+  std::string hash_name = gogo->hash_function_name(type);
 
   Location bloc = Linemap::predeclared_location();
 
-  const Package* package = NULL;
-  bool is_defined_elsewhere =
-    this->type_descriptor_defined_elsewhere(name, &package);
-
-  Named_object* hash_fn;
-  if (is_defined_elsewhere)
-    hash_fn = Named_object::make_function_declaration(hash_name, package,
-						      hash_fntype, bloc);
-  else
-    hash_fn = gogo->declare_package_function(hash_name, hash_fntype, bloc);
+  Named_object* hash_fn = gogo->declare_package_function(hash_name,
+							 hash_fntype, bloc);
 
   ins.first->second = hash_fn;
 
-  if (!is_defined_elsewhere)
-    {
-      if (gogo->in_global_scope())
-	this->write_hash_function(gogo, name, size, hash_name, hash_fntype);
-      else
-	gogo->queue_hash_function(this, name, size, hash_name, hash_fntype);
-    }
+  if (gogo->in_global_scope())
+    type->write_hash_function(gogo, size, hash_name, hash_fntype);
+  else
+    gogo->queue_hash_function(type, size, hash_name, hash_fntype);
 
   return hash_fn;
 }
@@ -1958,7 +1944,7 @@  Type::build_hash_function(Gogo* gogo, Na
 // Write the hash function for a type that needs it written specially.
 
 void
-Type::write_hash_function(Gogo* gogo, Named_type* name, int64_t size,
+Type::write_hash_function(Gogo* gogo, int64_t size,
 			  const std::string& hash_name,
 			  Function_type* hash_fntype)
 {
@@ -1979,12 +1965,10 @@  Type::write_hash_function(Gogo* gogo, Na
 
   if (size != -1)
     this->write_identity_hash(gogo, size);
-  else if (name != NULL && name->real_type()->named_type() != NULL)
-    this->write_named_hash(gogo, name, hash_fntype);
   else if (this->struct_type() != NULL)
-    this->struct_type()->write_hash_function(gogo, name, hash_fntype);
+    this->struct_type()->write_hash_function(gogo, hash_fntype);
   else if (this->array_type() != NULL)
-    this->array_type()->write_hash_function(gogo, name, hash_fntype);
+    this->array_type()->write_hash_function(gogo, hash_fntype);
   else
     go_unreachable();
 
@@ -2052,54 +2036,6 @@  Type::write_identity_hash(Gogo* gogo, in
   gogo->add_statement(s);
 }
 
-// Write a hash function that simply calls the hash function for a
-// named type.  This is used when one named type is defined as
-// another.  This ensures that this case works when the other named
-// type is defined in another package and relies on calling hash
-// functions defined only in that package.
-
-void
-Type::write_named_hash(Gogo* gogo, Named_type* name,
-		       Function_type* hash_fntype)
-{
-  Location bloc = Linemap::predeclared_location();
-
-  Named_type* base_type = name->real_type()->named_type();
-  while (base_type->is_alias())
-    {
-      base_type = base_type->real_type()->named_type();
-      go_assert(base_type != NULL);
-    }
-  go_assert(base_type != NULL);
-
-  // The pointer to the type we are going to hash.  This is an
-  // unsafe.Pointer.
-  Named_object* key_arg = gogo->lookup("key", NULL);
-  go_assert(key_arg != NULL);
-
-  // The seed argument to the hash function.
-  Named_object* seed_arg = gogo->lookup("seed", NULL);
-  go_assert(seed_arg != NULL);
-
-  Named_object* hash_fn = name->real_type()->hash_function(gogo, base_type,
-							   hash_fntype);
-
-  // Call the hash function for the base type.
-  Expression* key_ref = Expression::make_var_reference(key_arg, bloc);
-  Expression* seed_ref = Expression::make_var_reference(seed_arg, bloc);
-  Expression_list* args = new Expression_list();
-  args->push_back(key_ref);
-  args->push_back(seed_ref);
-  Expression* func = Expression::make_func_reference(hash_fn, NULL, bloc);
-  Expression* call = Expression::make_call(func, args, false, bloc);
-
-  // Return the hash of the base type.
-  Expression_list* vals = new Expression_list();
-  vals->push_back(call);
-  Statement* s = Statement::make_return_statement(vals, bloc);
-  gogo->add_statement(s);
-}
-
 // Return the runtime function that compares whether two values of
 // this type are equal.  If NAME is not NULL it is the name of this
 // type.  EQUAL_FNTYPE is the type of the equality function, for
@@ -2572,9 +2508,11 @@  Type::type_descriptor_constructor(Gogo*
   vals->push_back(Expression::make_integer_ul(h, p->type(), bloc));
 
   ++p;
-  go_assert(p->is_field_name("kind"));
-  vals->push_back(Expression::make_integer_ul(runtime_type_kind, p->type(),
-					      bloc));
+  go_assert(p->is_field_name("tflag"));
+  unsigned long tflag = 0;
+  if (this->compare_is_identity(gogo))
+    tflag |= TFLAG_REGULAR_MEMORY;
+  vals->push_back(Expression::make_integer_ul(tflag, p->type(), bloc));
 
   ++p;
   go_assert(p->is_field_name("align"));
@@ -2587,18 +2525,12 @@  Type::type_descriptor_constructor(Gogo*
   vals->push_back(Expression::make_type_info(this, type_info));
 
   ++p;
-  go_assert(p->is_field_name("hashfn"));
-  Function_type* hash_fntype = p->type()->function_type();
-  Named_object* hash_fn = this->hash_function(gogo, name, hash_fntype);
-  if (hash_fn == NULL)
-    vals->push_back(Expression::make_cast(hash_fntype,
-					  Expression::make_nil(bloc),
-					  bloc));
-  else
-    vals->push_back(Expression::make_func_reference(hash_fn, NULL, bloc));
+  go_assert(p->is_field_name("kind"));
+  vals->push_back(Expression::make_integer_ul(runtime_type_kind, p->type(),
+					      bloc));
 
   ++p;
-  go_assert(p->is_field_name("equalfn"));
+  go_assert(p->is_field_name("equal"));
   Function_type* equal_fntype = p->type()->function_type();
   Named_object* equal_fn = this->equal_function(gogo, name, equal_fntype);
   if (equal_fn == NULL)
@@ -6603,8 +6535,7 @@  Struct_type::do_type_descriptor(Gogo* go
 // function.
 
 void
-Struct_type::write_hash_function(Gogo* gogo, Named_type*,
-				 Function_type* hash_fntype)
+Struct_type::write_hash_function(Gogo* gogo, Function_type* hash_fntype)
 {
   Location bloc = Linemap::predeclared_location();
 
@@ -6650,8 +6581,7 @@  Struct_type::write_hash_function(Gogo* g
       subkey = Expression::make_cast(key_arg_type, subkey, bloc);
 
       // Get the hash function to use for the type of this field.
-      Named_object* hash_fn =
-	pf->type()->hash_function(gogo, pf->type()->named_type(), hash_fntype);
+      Named_object* hash_fn = pf->type()->hash_function(gogo, hash_fntype);
 
       // Call the hash function for the field, passing retval as the seed.
       ref = Expression::make_temporary_reference(retval, bloc);
@@ -7447,8 +7377,7 @@  Array_type::do_hash_for_method(Gogo* gog
 // function.
 
 void
-Array_type::write_hash_function(Gogo* gogo, Named_type* name,
-				Function_type* hash_fntype)
+Array_type::write_hash_function(Gogo* gogo, Function_type* hash_fntype)
 {
   Location bloc = Linemap::predeclared_location();
 
@@ -7485,9 +7414,7 @@  Array_type::write_hash_function(Gogo* go
 
   Expression* iref = Expression::make_temporary_reference(index, bloc);
   Expression* aref = Expression::make_var_reference(key_arg, bloc);
-  Type* pt = Type::make_pointer_type(name != NULL
-				     ? static_cast<Type*>(name)
-				     : static_cast<Type*>(this));
+  Type* pt = Type::make_pointer_type(static_cast<Type*>(this));
   aref = Expression::make_cast(pt, aref, bloc);
   For_range_statement* for_range = Statement::make_for_range_statement(iref,
 								       NULL,
@@ -7497,9 +7424,8 @@  Array_type::write_hash_function(Gogo* go
   gogo->start_block(bloc);
 
   // Get the hash function for the element type.
-  Named_object* hash_fn =
-    this->element_type_->hash_function(gogo, this->element_type_->named_type(),
-				       hash_fntype);
+  Named_object* hash_fn = this->element_type_->hash_function(gogo,
+							     hash_fntype);
 
   // Get a pointer to this element in the loop.
   Expression* subkey = Expression::make_temporary_reference(key, bloc);
@@ -8291,13 +8217,28 @@  Map_type::make_map_type_descriptor_type(
       Type* uint8_type = Type::lookup_integer_type("uint8");
       Type* uint16_type = Type::lookup_integer_type("uint16");
       Type* uint32_type = Type::lookup_integer_type("uint32");
+      Type* uintptr_type = Type::lookup_integer_type("uintptr");
+      Type* void_type = Type::make_void_type();
+      Type* unsafe_pointer_type = Type::make_pointer_type(void_type);
+
+      Location bloc = Linemap::predeclared_location();
+      Typed_identifier_list *params = new Typed_identifier_list();
+      params->push_back(Typed_identifier("key", unsafe_pointer_type, bloc));
+      params->push_back(Typed_identifier("seed", uintptr_type, bloc));
+
+      Typed_identifier_list* results = new Typed_identifier_list();
+      results->push_back(Typed_identifier("", uintptr_type, bloc));
+
+      Type* hasher_fntype = Type::make_function_type(NULL, params, results,
+						     bloc);
 
       Struct_type* sf =
-	Type::make_builtin_struct_type(8,
+	Type::make_builtin_struct_type(9,
 				       "", tdt,
 				       "key", ptdt,
 				       "elem", ptdt,
 				       "bucket", ptdt,
+				       "hasher", hasher_fntype,
 				       "keysize", uint8_type,
 				       "valuesize", uint8_type,
 				       "bucketsize", uint16_type,
@@ -8380,6 +8321,18 @@  Map_type::do_type_descriptor(Gogo* gogo,
   vals->push_back(Expression::make_type_descriptor(bucket_type, bloc));
 
   ++p;
+  go_assert(p->is_field_name("hasher"));
+  Function_type* hasher_fntype = p->type()->function_type();
+  Named_object* hasher_fn = this->key_type_->hash_function(gogo,
+							   hasher_fntype);
+  if (hasher_fn == NULL)
+    vals->push_back(Expression::make_cast(hasher_fntype,
+					  Expression::make_nil(bloc),
+					  bloc));
+  else
+    vals->push_back(Expression::make_func_reference(hasher_fn, NULL, bloc));
+
+  ++p;
   go_assert(p->is_field_name("keysize"));
   if (keysize > Map_type::max_key_size)
     vals->push_back(Expression::make_integer_int64(ptrsize, uint8_type, bloc));
Index: gcc/go/gofrontend/types.h
===================================================================
--- gcc/go/gofrontend/types.h	(revision 279847)
+++ gcc/go/gofrontend/types.h	(working copy)
@@ -1061,7 +1061,7 @@  class Type
   // Get the hash function for a type.  Returns NULL if the type is
   // not comparable.
   Named_object*
-  hash_function(Gogo*, Named_type* name, Function_type* hash_fntype);
+  hash_function(Gogo*, Function_type* hash_fntype);
 
   // Write the equal function for a type.
   void
@@ -1071,8 +1071,7 @@  class Type
 
   // Write the hash function for a type.
   void
-  write_hash_function(Gogo*, Named_type*, int64_t size,
-		      const std::string& hash_name,
+  write_hash_function(Gogo*, int64_t size, const std::string& hash_name,
 		      Function_type* hash_fntype);
 
   // Return the alignment required by the memequalN function.
@@ -1284,8 +1283,7 @@  class Type
 
   // Build the hash function for a type that needs specific functions.
   Named_object*
-  build_hash_function(Gogo*, Named_type*, int64_t size,
-		      Function_type* hash_fntype);
+  build_hash_function(Gogo*, int64_t size, Function_type* hash_fntype);
 
   // Build the equal function for a type that needs specific functions.
   Named_object*
@@ -1299,9 +1297,6 @@  class Type
   write_identity_equal(Gogo*, int64_t size);
 
   void
-  write_named_hash(Gogo*, Named_type*, Function_type* hash_fntype);
-
-  void
   write_named_equal(Gogo*, Named_type*);
 
   // Build a composite literal for the uncommon type information.
@@ -2628,7 +2623,7 @@  class Struct_type : public Type
 
   // Write the hash function for this type.
   void
-  write_hash_function(Gogo*, Named_type*, Function_type*);
+  write_hash_function(Gogo*, Function_type*);
 
   // Write the equality function for this type.
   void
@@ -2815,7 +2810,7 @@  class Array_type : public Type
 
   // Write the hash function for this type.
   void
-  write_hash_function(Gogo*, Named_type*, Function_type*);
+  write_hash_function(Gogo*, Function_type*);
 
   // Write the equality function for this type.
   void
Index: libgo/go/internal/reflectlite/type.go
===================================================================
--- libgo/go/internal/reflectlite/type.go	(revision 279815)
+++ libgo/go/internal/reflectlite/type.go	(working copy)
@@ -110,33 +110,14 @@  const (
 // available in the memory directly following the rtype value.
 //
 // tflag values must be kept in sync with copies in:
-//	cmd/compile/internal/gc/reflect.go
-//	cmd/link/internal/ld/decodesym.go
+//	go/types.cc
 //	runtime/type.go
 type tflag uint8
 
 const (
-	// tflagUncommon means that there is a pointer, *uncommonType,
-	// just beyond the outer type structure.
-	//
-	// For example, if t.Kind() == Struct and t.tflag&tflagUncommon != 0,
-	// then t has uncommonType data and it can be accessed as:
-	//
-	//	type tUncommon struct {
-	//		structType
-	//		u uncommonType
-	//	}
-	//	u := &(*tUncommon)(unsafe.Pointer(t)).u
-	tflagUncommon tflag = 1 << 0
-
-	// tflagExtraStar means the name in the str field has an
-	// extraneous '*' prefix. This is because for most types T in
-	// a program, the type *T also exists and reusing the str data
-	// saves binary size.
-	tflagExtraStar tflag = 1 << 1
-
-	// tflagNamed means the type has a name.
-	tflagNamed tflag = 1 << 2
+	// tflagRegularMemory means that equal and hash functions can treat
+	// this type as a single region of t.size bytes.
+	tflagRegularMemory tflag = 1 << 3
 )
 
 // rtype is the common implementation of most values.
@@ -147,16 +128,15 @@  type rtype struct {
 	size       uintptr
 	ptrdata    uintptr // number of bytes in the type that can contain pointers
 	hash       uint32  // hash of type; avoids computation in hash tables
-	kind       uint8   // enumeration for C
+	tflag      tflag   // extra type information flags
 	align      uint8   // alignment of variable with this type
 	fieldAlign uint8   // alignment of struct field with this type
-	_          uint8   // unused/padding
-
-	hashfn  func(unsafe.Pointer, uintptr) uintptr     // hash function
-	equalfn func(unsafe.Pointer, unsafe.Pointer) bool // equality function
-
+	kind       uint8   // enumeration for C
+	// function for comparing objects of this type
+	// (ptr to object A, ptr to object B) -> ==?
+	equal         func(unsafe.Pointer, unsafe.Pointer) bool
 	gcdata        *byte   // garbage collection data
-	string        *string // string form; unnecessary  but undeniably useful
+	string        *string // string form; unnecessary but undeniably useful
 	*uncommonType         // (relatively) uncommon fields
 	ptrToThis     *rtype  // type for pointer to this type, may be zero
 }
Index: libgo/go/reflect/type.go
===================================================================
--- libgo/go/reflect/type.go	(revision 279815)
+++ libgo/go/reflect/type.go	(working copy)
@@ -261,6 +261,20 @@  const (
 	UnsafePointer
 )
 
+// tflag is used by an rtype to signal what extra type information is
+// available in the memory directly following the rtype value.
+//
+// tflag values must be kept in sync with copies in:
+//	go/types.cc
+//	runtime/type.go
+type tflag uint8
+
+const (
+	// tflagRegularMemory means that equal and hash functions can treat
+	// this type as a single region of t.size bytes.
+	tflagRegularMemory tflag = 1 << 3
+)
+
 // rtype is the common implementation of most values.
 // It is embedded in other struct types.
 //
@@ -269,16 +283,15 @@  type rtype struct {
 	size       uintptr
 	ptrdata    uintptr // size of memory prefix holding all pointers
 	hash       uint32  // hash of type; avoids computation in hash tables
-	kind       uint8   // enumeration for C
-	align      int8    // alignment of variable with this type
+	tflag      tflag   // extra type information flags
+	align      uint8   // alignment of variable with this type
 	fieldAlign uint8   // alignment of struct field with this type
-	_          uint8   // unused/padding
-
-	hashfn  func(unsafe.Pointer, uintptr) uintptr     // hash function
-	equalfn func(unsafe.Pointer, unsafe.Pointer) bool // equality function
-
+	kind       uint8   // enumeration for C
+	// function for comparing objects of this type
+	// (ptr to object A, ptr to object B) -> ==?
+	equal         func(unsafe.Pointer, unsafe.Pointer) bool
 	gcdata        *byte   // garbage collection data
-	string        *string // string form; unnecessary  but undeniably useful
+	string        *string // string form; unnecessary but undeniably useful
 	*uncommonType         // (relatively) uncommon fields
 	ptrToThis     *rtype  // type for pointer to this type, if used in binary or has methods
 }
@@ -350,9 +363,11 @@  type interfaceType struct {
 // mapType represents a map type.
 type mapType struct {
 	rtype
-	key        *rtype // map key type
-	elem       *rtype // map element (value) type
-	bucket     *rtype // internal bucket structure
+	key    *rtype // map key type
+	elem   *rtype // map element (value) type
+	bucket *rtype // internal bucket structure
+	// function for hashing keys (ptr to key, seed) -> hash
+	hasher     func(unsafe.Pointer, uintptr) uintptr
 	keysize    uint8  // size of key slot
 	valuesize  uint8  // size of value slot
 	bucketsize uint16 // size of bucket
@@ -1178,31 +1193,7 @@  func (t *rtype) ConvertibleTo(u Type) bo
 }
 
 func (t *rtype) Comparable() bool {
-	switch t.Kind() {
-	case Bool, Int, Int8, Int16, Int32, Int64,
-		Uint, Uint8, Uint16, Uint32, Uint64, Uintptr,
-		Float32, Float64, Complex64, Complex128,
-		Chan, Interface, Ptr, String, UnsafePointer:
-		return true
-
-	case Func, Map, Slice:
-		return false
-
-	case Array:
-		return (*arrayType)(unsafe.Pointer(t)).elem.Comparable()
-
-	case Struct:
-		tt := (*structType)(unsafe.Pointer(t))
-		for i := range tt.fields {
-			if !tt.fields[i].typ.Comparable() {
-				return false
-			}
-		}
-		return true
-
-	default:
-		panic("reflect: impossible")
-	}
+	return t.equal != nil
 }
 
 // implements reports whether the type V implements the interface type T.
@@ -1457,6 +1448,7 @@  func ChanOf(dir ChanDir, t Type) Type {
 	var ichan interface{} = (chan unsafe.Pointer)(nil)
 	prototype := *(**chanType)(unsafe.Pointer(&ichan))
 	ch := *prototype
+	ch.tflag = tflagRegularMemory
 	ch.dir = uintptr(dir)
 	ch.string = &s
 
@@ -1481,8 +1473,6 @@  func ChanOf(dir ChanDir, t Type) Type {
 	return ti.(Type)
 }
 
-func ismapkey(*rtype) bool // implemented in runtime
-
 // MapOf returns the map type with the given key and element types.
 // For example, if k represents int and e represents string,
 // MapOf(k, e) represents map[int]string.
@@ -1493,7 +1483,7 @@  func MapOf(key, elem Type) Type {
 	ktyp := key.(*rtype)
 	etyp := elem.(*rtype)
 
-	if !ismapkey(ktyp) {
+	if ktyp.equal == nil {
 		panic("reflect.MapOf: invalid key type " + ktyp.String())
 	}
 
@@ -1530,6 +1520,9 @@  func MapOf(key, elem Type) Type {
 	mt.ptrToThis = nil
 
 	mt.bucket = bucketOf(ktyp, etyp)
+	mt.hasher = func(p unsafe.Pointer, seed uintptr) uintptr {
+		return typehash(ktyp, p, seed)
+	}
 	mt.flags = 0
 	if ktyp.size > maxKeySize {
 		mt.keysize = uint8(ptrSize)
@@ -1851,7 +1844,7 @@  func bucketOf(ktyp, etyp *rtype) *rtype
 	}
 
 	b := &rtype{
-		align:      int8(maxAlign),
+		align:      uint8(maxAlign),
 		fieldAlign: uint8(maxAlign),
 		size:       size,
 		kind:       uint8(Struct),
@@ -1949,9 +1942,8 @@  func StructOf(fields []StructField) Type
 	var (
 		hash       = uint32(12)
 		size       uintptr
-		typalign   int8
+		typalign   uint8
 		comparable = true
-		hashable   = true
 
 		fs   = make([]structField, len(fields))
 		repr = make([]byte, 0, 64)
@@ -2036,12 +2028,11 @@  func StructOf(fields []StructField) Type
 			repr = append(repr, ';')
 		}
 
-		comparable = comparable && (ft.equalfn != nil)
-		hashable = hashable && (ft.hashfn != nil)
+		comparable = comparable && (ft.equal != nil)
 
 		offset := align(size, uintptr(ft.fieldAlign))
-		if int8(ft.fieldAlign) > typalign {
-			typalign = int8(ft.fieldAlign)
+		if ft.fieldAlign > typalign {
+			typalign = ft.fieldAlign
 		}
 		size = offset + ft.size
 		f.offsetEmbed |= offset << 1
@@ -2118,11 +2109,12 @@  func StructOf(fields []StructField) Type
 	}
 
 	typ.string = &str
+	typ.tflag = 0 // TODO: set tflagRegularMemory
 	typ.hash = hash
 	typ.size = size
 	typ.ptrdata = typeptrdata(typ.common())
 	typ.align = typalign
-	typ.fieldAlign = uint8(typalign)
+	typ.fieldAlign = typalign
 
 	if hasGCProg {
 		lastPtrField := 0
@@ -2189,32 +2181,18 @@  func StructOf(fields []StructField) Type
 	}
 	typ.ptrdata = typeptrdata(typ.common())
 
-	if hashable {
-		typ.hashfn = func(p unsafe.Pointer, seed uintptr) uintptr {
-			o := seed
-			for _, ft := range typ.fields {
-				pi := add(p, ft.offset(), "&x.field safe")
-				o = ft.typ.hashfn(pi, o)
-			}
-			return o
-		}
-	} else {
-		typ.hashfn = nil
-	}
-
+	typ.equal = nil
 	if comparable {
-		typ.equalfn = func(p, q unsafe.Pointer) bool {
+		typ.equal = func(p, q unsafe.Pointer) bool {
 			for _, ft := range typ.fields {
 				pi := add(p, ft.offset(), "&x.field safe")
 				qi := add(q, ft.offset(), "&x.field safe")
-				if !ft.typ.equalfn(pi, qi) {
+				if !ft.typ.equal(pi, qi) {
 					return false
 				}
 			}
 			return true
 		}
-	} else {
-		typ.equalfn = nil
 	}
 
 	switch {
@@ -2322,6 +2300,7 @@  func ArrayOf(count int, elem Type) Type
 	var iarray interface{} = [1]unsafe.Pointer{}
 	prototype := *(**arrayType)(unsafe.Pointer(&iarray))
 	array := *prototype
+	array.tflag = typ.tflag & tflagRegularMemory
 	array.string = &s
 
 	// gccgo uses a different hash.
@@ -2427,21 +2406,12 @@  func ArrayOf(count int, elem Type) Type
 		array.ptrdata = array.size // overestimate but ok; must match program
 	}
 
-	switch {
-	case count == 1 && !ifaceIndir(typ):
-		// array of 1 direct iface type can be direct
-		array.kind |= kindDirectIface
-	default:
-		array.kind &^= kindDirectIface
-	}
-
+	etyp := typ.common()
 	esize := typ.size
 
-	if typ.equalfn == nil {
-		array.equalfn = nil
-	} else {
-		eequal := typ.equalfn
-		array.equalfn = func(p, q unsafe.Pointer) bool {
+	array.equal = nil
+	if eequal := etyp.equal; eequal != nil {
+		array.equal = func(p, q unsafe.Pointer) bool {
 			for i := 0; i < count; i++ {
 				pi := arrayAt(p, i, esize, "i < count")
 				qi := arrayAt(q, i, esize, "i < count")
@@ -2453,17 +2423,12 @@  func ArrayOf(count int, elem Type) Type
 		}
 	}
 
-	if typ.hashfn == nil {
-		array.hashfn = nil
-	} else {
-		ehash := typ.hashfn
-		array.hashfn = func(ptr unsafe.Pointer, seed uintptr) uintptr {
-			o := seed
-			for i := 0; i < count; i++ {
-				o = ehash(arrayAt(ptr, i, esize, "i < count"), o)
-			}
-			return o
-		}
+	switch {
+	case count == 1 && !ifaceIndir(typ):
+		// array of 1 direct iface type can be direct
+		array.kind |= kindDirectIface
+	default:
+		array.kind &^= kindDirectIface
 	}
 
 	ti, _ := lookupCache.LoadOrStore(ckey, &array.rtype)
Index: libgo/go/reflect/value.go
===================================================================
--- libgo/go/reflect/value.go	(revision 279815)
+++ libgo/go/reflect/value.go	(working copy)
@@ -2543,6 +2543,9 @@  func typedmemmove(t *rtype, dst, src uns
 //go:noescape
 func typedslicecopy(elemType *rtype, dst, src sliceHeader) int
 
+//go:noescape
+func typehash(t *rtype, p unsafe.Pointer, h uintptr) uintptr
+
 // Dummy annotation marking that the value x escapes,
 // for use in cases where the reflect code is so clever that
 // the compiler cannot follow.
Index: libgo/go/runtime/alg.go
===================================================================
--- libgo/go/runtime/alg.go	(revision 279815)
+++ libgo/go/runtime/alg.go	(working copy)
@@ -69,6 +69,9 @@  func memhash128(p unsafe.Pointer, h uint
 	return memhash(p, h, 16)
 }
 
+// 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 C code
@@ -134,14 +137,17 @@  func interhash(p unsafe.Pointer, h uintp
 		return h
 	}
 	t := *(**_type)(tab)
-	fn := t.hashfn
-	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)
 	}
 }
 
@@ -151,17 +157,74 @@  func nilinterhash(p unsafe.Pointer, h ui
 	if t == nil {
 		return h
 	}
-	fn := t.hashfn
-	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.methods) == 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 != nil && *f.name == "_" {
+				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 {
 	return true
 }
@@ -209,7 +272,7 @@  func efaceeq(x, y eface) bool {
 	if t == nil {
 		return true
 	}
-	eq := t.equalfn
+	eq := t.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + t.string()))
 	}
@@ -230,7 +293,7 @@  func ifaceeq(x, y iface) bool {
 	if t != *(**_type)(y.tab) {
 		return false
 	}
-	eq := t.equalfn
+	eq := t.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + t.string()))
 	}
@@ -251,7 +314,7 @@  func ifacevaleq(x iface, t *_type, p uns
 	if xt != t {
 		return false
 	}
-	eq := t.equalfn
+	eq := t.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + t.string()))
 	}
@@ -272,7 +335,7 @@  func ifaceefaceeq(x iface, y eface) bool
 	if xt != y._type {
 		return false
 	}
-	eq := xt.equalfn
+	eq := xt.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + xt.string()))
 	}
@@ -289,7 +352,7 @@  func efacevaleq(x eface, t *_type, p uns
 	if x._type != t {
 		return false
 	}
-	eq := t.equalfn
+	eq := t.equal
 	if eq == nil {
 		panic(errorString("comparing uncomparable type " + t.string()))
 	}
Index: libgo/go/runtime/map.go
===================================================================
--- libgo/go/runtime/map.go	(revision 279815)
+++ libgo/go/runtime/map.go	(working copy)
@@ -421,18 +421,16 @@  func mapaccess1(t *maptype, h *hmap, key
 	if msanenabled && h != nil {
 		msanread(key, t.key.size)
 	}
-	hashfn := t.key.hashfn
-	equalfn := t.key.equalfn
 	if h == nil || h.count == 0 {
 		if t.hashMightPanic() {
-			hashfn(key, 0) // see issue 23734
+			t.hasher(key, 0) // see issue 23734
 		}
 		return unsafe.Pointer(&zeroVal[0])
 	}
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map read and map write")
 	}
-	hash := hashfn(key, uintptr(h.hash0))
+	hash := t.hasher(key, uintptr(h.hash0))
 	m := bucketMask(h.B)
 	b := (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 	if c := h.oldbuckets; c != nil {
@@ -459,7 +457,7 @@  bucketloop:
 			if t.indirectkey() {
 				k = *((*unsafe.Pointer)(k))
 			}
-			if equalfn(key, k) {
+			if t.key.equal(key, k) {
 				e := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.elemsize))
 				if t.indirectelem() {
 					e = *((*unsafe.Pointer)(e))
@@ -486,18 +484,16 @@  func mapaccess2(t *maptype, h *hmap, key
 	if msanenabled && h != nil {
 		msanread(key, t.key.size)
 	}
-	hashfn := t.key.hashfn
-	equalfn := t.key.equalfn
 	if h == nil || h.count == 0 {
 		if t.hashMightPanic() {
-			hashfn(key, 0) // see issue 23734
+			t.hasher(key, 0) // see issue 23734
 		}
 		return unsafe.Pointer(&zeroVal[0]), false
 	}
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map read and map write")
 	}
-	hash := hashfn(key, uintptr(h.hash0))
+	hash := t.hasher(key, uintptr(h.hash0))
 	m := bucketMask(h.B)
 	b := (*bmap)(unsafe.Pointer(uintptr(h.buckets) + (hash&m)*uintptr(t.bucketsize)))
 	if c := h.oldbuckets; c != nil {
@@ -524,7 +520,7 @@  bucketloop:
 			if t.indirectkey() {
 				k = *((*unsafe.Pointer)(k))
 			}
-			if equalfn(key, k) {
+			if t.key.equal(key, k) {
 				e := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.elemsize))
 				if t.indirectelem() {
 					e = *((*unsafe.Pointer)(e))
@@ -546,9 +542,7 @@  func mapaccessK(t *maptype, h *hmap, key
 	if h == nil || h.count == 0 {
 		return nil, nil
 	}
-	hashfn := t.key.hashfn
-	equalfn := t.key.equalfn
-	hash := hashfn(key, uintptr(h.hash0))
+	hash := t.hasher(key, uintptr(h.hash0))
 	m := bucketMask(h.B)
 	b := (*bmap)(unsafe.Pointer(uintptr(h.buckets) + (hash&m)*uintptr(t.bucketsize)))
 	if c := h.oldbuckets; c != nil {
@@ -575,7 +569,7 @@  bucketloop:
 			if t.indirectkey() {
 				k = *((*unsafe.Pointer)(k))
 			}
-			if equalfn(key, k) {
+			if t.key.equal(key, k) {
 				e := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.elemsize))
 				if t.indirectelem() {
 					e = *((*unsafe.Pointer)(e))
@@ -625,11 +619,9 @@  func mapassign(t *maptype, h *hmap, key
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map writes")
 	}
-	hashfn := t.key.hashfn
-	equalfn := t.key.equalfn
-	hash := hashfn(key, uintptr(h.hash0))
+	hash := t.hasher(key, uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash, since alg.hash may panic,
+	// Set hashWriting after calling t.hasher, since t.hasher may panic,
 	// in which case we have not actually done a write.
 	h.flags ^= hashWriting
 
@@ -666,7 +658,7 @@  bucketloop:
 			if t.indirectkey() {
 				k = *((*unsafe.Pointer)(k))
 			}
-			if !equalfn(key, k) {
+			if !t.key.equal(key, k) {
 				continue
 			}
 			// already have a mapping for key. Update it.
@@ -735,11 +727,9 @@  func mapdelete(t *maptype, h *hmap, key
 	if msanenabled && h != nil {
 		msanread(key, t.key.size)
 	}
-	hashfn := t.key.hashfn
-	equalfn := t.key.equalfn
 	if h == nil || h.count == 0 {
 		if t.hashMightPanic() {
-			hashfn(key, 0) // see issue 23734
+			t.hasher(key, 0) // see issue 23734
 		}
 		return
 	}
@@ -747,9 +737,9 @@  func mapdelete(t *maptype, h *hmap, key
 		throw("concurrent map writes")
 	}
 
-	hash := hashfn(key, uintptr(h.hash0))
+	hash := t.hasher(key, uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash, since alg.hash may panic,
+	// Set hashWriting after calling t.hasher, since t.hasher may panic,
 	// in which case we have not actually done a write (delete).
 	h.flags ^= hashWriting
 
@@ -774,7 +764,7 @@  search:
 			if t.indirectkey() {
 				k2 = *((*unsafe.Pointer)(k2))
 			}
-			if !equalfn(key, k2) {
+			if !t.key.equal(key, k2) {
 				continue
 			}
 			// Only clear key if there are pointers in it.
@@ -925,8 +915,6 @@  func mapiternext(it *hiter) {
 	b := it.bptr
 	i := it.i
 	checkBucket := it.checkBucket
-	hashfn := t.key.hashfn
-	equalfn := t.key.equalfn
 
 next:
 	if b == nil {
@@ -980,10 +968,10 @@  next:
 			// through the oldbucket, skipping any keys that will go
 			// to the other new bucket (each oldbucket expands to two
 			// buckets during a grow).
-			if t.reflexivekey() || equalfn(k, k) {
+			if t.reflexivekey() || t.key.equal(k, k) {
 				// If the item in the oldbucket is not destined for
 				// the current new bucket in the iteration, skip it.
-				hash := hashfn(k, uintptr(h.hash0))
+				hash := t.hasher(k, uintptr(h.hash0))
 				if hash&bucketMask(it.B) != checkBucket {
 					continue
 				}
@@ -1001,7 +989,7 @@  next:
 			}
 		}
 		if (b.tophash[offi] != evacuatedX && b.tophash[offi] != evacuatedY) ||
-			!(t.reflexivekey() || equalfn(k, k)) {
+			!(t.reflexivekey() || t.key.equal(k, k)) {
 			// This is the golden data, we can return it.
 			// OR
 			// key!=key, so the entry can't be deleted or updated, so we can just return it.
@@ -1238,8 +1226,8 @@  func evacuate(t *maptype, h *hmap, oldbu
 				if !h.sameSizeGrow() {
 					// Compute hash to make our evacuation decision (whether we need
 					// to send this key/elem to bucket x or bucket y).
-					hash := t.key.hashfn(k2, uintptr(h.hash0))
-					if h.flags&iterator != 0 && !t.reflexivekey() && !t.key.equalfn(k2, k2) {
+					hash := t.hasher(k2, uintptr(h.hash0))
+					if h.flags&iterator != 0 && !t.reflexivekey() && !t.key.equal(k2, k2) {
 						// If key != key (NaNs), then the hash could be (and probably
 						// will be) entirely different from the old hash. Moreover,
 						// it isn't reproducible. Reproducibility is required in the
@@ -1333,16 +1321,12 @@  func advanceEvacuationMark(h *hmap, t *m
 	}
 }
 
-func ismapkey(t *_type) bool {
-	return t.hashfn != nil
-}
-
 // Reflect stubs. Called from ../reflect/asm_*.s
 
 //go:linkname reflect_makemap reflect.makemap
 func reflect_makemap(t *maptype, cap int) *hmap {
 	// Check invariants and reflects math.
-	if !ismapkey(t.key) {
+	if t.key.equal == nil {
 		throw("runtime.reflect_makemap: unsupported map key type")
 	}
 	if t.key.size > maxKeySize && (!t.indirectkey() || t.keysize != uint8(sys.PtrSize)) ||
@@ -1445,10 +1429,5 @@  func reflectlite_maplen(h *hmap) int {
 	return h.count
 }
 
-//go:linkname reflect_ismapkey reflect.ismapkey
-func reflect_ismapkey(t *_type) bool {
-	return ismapkey(t)
-}
-
 const maxZero = 1024 // must match value in cmd/compile/internal/gc/walk.go
 var zeroVal [maxZero]byte
Index: libgo/go/runtime/map_benchmark_test.go
===================================================================
--- libgo/go/runtime/map_benchmark_test.go	(revision 279815)
+++ libgo/go/runtime/map_benchmark_test.go	(working copy)
@@ -483,3 +483,33 @@  func BenchmarkMapStringConversion(b *tes
 		})
 	}
 }
+
+var BoolSink bool
+
+func BenchmarkMapInterfaceString(b *testing.B) {
+	m := map[interface{}]bool{}
+
+	for i := 0; i < 100; i++ {
+		m[fmt.Sprintf("%d", i)] = true
+	}
+
+	key := (interface{})("A")
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		BoolSink = m[key]
+	}
+}
+func BenchmarkMapInterfacePtr(b *testing.B) {
+	m := map[interface{}]bool{}
+
+	for i := 0; i < 100; i++ {
+		i := i
+		m[&i] = true
+	}
+
+	key := new(int)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		BoolSink = m[key]
+	}
+}
Index: libgo/go/runtime/map_fast32.go
===================================================================
--- libgo/go/runtime/map_fast32.go	(revision 279815)
+++ libgo/go/runtime/map_fast32.go	(working copy)
@@ -33,7 +33,7 @@  func mapaccess1_fast32(t *maptype, h *hm
 		// One-bucket table. No need to hash.
 		b = (*bmap)(h.buckets)
 	} else {
-		hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+		hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 		m := bucketMask(h.B)
 		b = (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 		if c := h.oldbuckets; c != nil {
@@ -73,7 +73,7 @@  func mapaccess2_fast32(t *maptype, h *hm
 		// One-bucket table. No need to hash.
 		b = (*bmap)(h.buckets)
 	} else {
-		hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+		hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 		m := bucketMask(h.B)
 		b = (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 		if c := h.oldbuckets; c != nil {
@@ -108,9 +108,9 @@  func mapassign_fast32(t *maptype, h *hma
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map writes")
 	}
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapassign.
+	// Set hashWriting after calling t.hasher for consistency with mapassign.
 	h.flags ^= hashWriting
 
 	if h.buckets == nil {
@@ -198,9 +198,9 @@  func mapassign_fast32ptr(t *maptype, h *
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map writes")
 	}
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapassign.
+	// Set hashWriting after calling t.hasher for consistency with mapassign.
 	h.flags ^= hashWriting
 
 	if h.buckets == nil {
@@ -289,9 +289,9 @@  func mapdelete_fast32(t *maptype, h *hma
 		throw("concurrent map writes")
 	}
 
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapdelete
+	// Set hashWriting after calling t.hasher for consistency with mapdelete
 	h.flags ^= hashWriting
 
 	bucket := hash & bucketMask(h.B)
@@ -408,7 +408,7 @@  func evacuate_fast32(t *maptype, h *hmap
 				if !h.sameSizeGrow() {
 					// Compute hash to make our evacuation decision (whether we need
 					// to send this key/elem to bucket x or bucket y).
-					hash := t.key.hashfn(k, uintptr(h.hash0))
+					hash := t.hasher(k, uintptr(h.hash0))
 					if hash&newbit != 0 {
 						useY = 1
 					}
Index: libgo/go/runtime/map_fast64.go
===================================================================
--- libgo/go/runtime/map_fast64.go	(revision 279815)
+++ libgo/go/runtime/map_fast64.go	(working copy)
@@ -33,7 +33,7 @@  func mapaccess1_fast64(t *maptype, h *hm
 		// One-bucket table. No need to hash.
 		b = (*bmap)(h.buckets)
 	} else {
-		hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+		hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 		m := bucketMask(h.B)
 		b = (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 		if c := h.oldbuckets; c != nil {
@@ -73,7 +73,7 @@  func mapaccess2_fast64(t *maptype, h *hm
 		// One-bucket table. No need to hash.
 		b = (*bmap)(h.buckets)
 	} else {
-		hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+		hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 		m := bucketMask(h.B)
 		b = (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 		if c := h.oldbuckets; c != nil {
@@ -108,9 +108,9 @@  func mapassign_fast64(t *maptype, h *hma
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map writes")
 	}
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapassign.
+	// Set hashWriting after calling t.hasher for consistency with mapassign.
 	h.flags ^= hashWriting
 
 	if h.buckets == nil {
@@ -198,9 +198,9 @@  func mapassign_fast64ptr(t *maptype, h *
 	if h.flags&hashWriting != 0 {
 		throw("concurrent map writes")
 	}
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapassign.
+	// Set hashWriting after calling t.hasher for consistency with mapassign.
 	h.flags ^= hashWriting
 
 	if h.buckets == nil {
@@ -289,9 +289,9 @@  func mapdelete_fast64(t *maptype, h *hma
 		throw("concurrent map writes")
 	}
 
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&key)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapdelete
+	// Set hashWriting after calling t.hasher for consistency with mapdelete
 	h.flags ^= hashWriting
 
 	bucket := hash & bucketMask(h.B)
@@ -408,7 +408,7 @@  func evacuate_fast64(t *maptype, h *hmap
 				if !h.sameSizeGrow() {
 					// Compute hash to make our evacuation decision (whether we need
 					// to send this key/elem to bucket x or bucket y).
-					hash := t.key.hashfn(k, uintptr(h.hash0))
+					hash := t.hasher(k, uintptr(h.hash0))
 					if hash&newbit != 0 {
 						useY = 1
 					}
Index: libgo/go/runtime/map_faststr.go
===================================================================
--- libgo/go/runtime/map_faststr.go	(revision 279815)
+++ libgo/go/runtime/map_faststr.go	(working copy)
@@ -83,7 +83,7 @@  func mapaccess1_faststr(t *maptype, h *h
 		return unsafe.Pointer(&zeroVal[0])
 	}
 dohash:
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&ky)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&ky)), uintptr(h.hash0))
 	m := bucketMask(h.B)
 	b := (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 	if c := h.oldbuckets; c != nil {
@@ -178,7 +178,7 @@  func mapaccess2_faststr(t *maptype, h *h
 		return unsafe.Pointer(&zeroVal[0]), false
 	}
 dohash:
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&ky)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&ky)), uintptr(h.hash0))
 	m := bucketMask(h.B)
 	b := (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
 	if c := h.oldbuckets; c != nil {
@@ -218,9 +218,9 @@  func mapassign_faststr(t *maptype, h *hm
 		throw("concurrent map writes")
 	}
 	key := stringStructOf(&s)
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&s)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&s)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapassign.
+	// Set hashWriting after calling t.hasher for consistency with mapassign.
 	h.flags ^= hashWriting
 
 	if h.buckets == nil {
@@ -314,9 +314,9 @@  func mapdelete_faststr(t *maptype, h *hm
 	}
 
 	key := stringStructOf(&ky)
-	hash := t.key.hashfn(noescape(unsafe.Pointer(&ky)), uintptr(h.hash0))
+	hash := t.hasher(noescape(unsafe.Pointer(&ky)), uintptr(h.hash0))
 
-	// Set hashWriting after calling alg.hash for consistency with mapdelete
+	// Set hashWriting after calling t.hasher for consistency with mapdelete
 	h.flags ^= hashWriting
 
 	bucket := hash & bucketMask(h.B)
@@ -436,7 +436,7 @@  func evacuate_faststr(t *maptype, h *hma
 				if !h.sameSizeGrow() {
 					// Compute hash to make our evacuation decision (whether we need
 					// to send this key/elem to bucket x or bucket y).
-					hash := t.key.hashfn(k, uintptr(h.hash0))
+					hash := t.hasher(k, uintptr(h.hash0))
 					if hash&newbit != 0 {
 						useY = 1
 					}
Index: libgo/go/runtime/map_test.go
===================================================================
--- libgo/go/runtime/map_test.go	(revision 279815)
+++ libgo/go/runtime/map_test.go	(working copy)
@@ -1172,3 +1172,64 @@  func TestMapTombstones(t *testing.T) {
 	}
 	runtime.MapTombstoneCheck(m)
 }
+
+type canString int
+
+func (c canString) String() string {
+	return fmt.Sprintf("%d", int(c))
+}
+
+func TestMapInterfaceKey(t *testing.T) {
+	// Test all the special cases in runtime.typehash.
+	type GrabBag struct {
+		f32  float32
+		f64  float64
+		c64  complex64
+		c128 complex128
+		s    string
+		i0   interface{}
+		i1   interface {
+			String() string
+		}
+		a [4]string
+	}
+
+	m := map[interface{}]bool{}
+	// Put a bunch of data in m, so that a bad hash is likely to
+	// lead to a bad bucket, which will lead to a missed lookup.
+	for i := 0; i < 1000; i++ {
+		m[i] = true
+	}
+	m[GrabBag{f32: 1.0}] = true
+	if !m[GrabBag{f32: 1.0}] {
+		panic("f32 not found")
+	}
+	m[GrabBag{f64: 1.0}] = true
+	if !m[GrabBag{f64: 1.0}] {
+		panic("f64 not found")
+	}
+	m[GrabBag{c64: 1.0i}] = true
+	if !m[GrabBag{c64: 1.0i}] {
+		panic("c64 not found")
+	}
+	m[GrabBag{c128: 1.0i}] = true
+	if !m[GrabBag{c128: 1.0i}] {
+		panic("c128 not found")
+	}
+	m[GrabBag{s: "foo"}] = true
+	if !m[GrabBag{s: "foo"}] {
+		panic("string not found")
+	}
+	m[GrabBag{i0: "foo"}] = true
+	if !m[GrabBag{i0: "foo"}] {
+		panic("interface{} not found")
+	}
+	m[GrabBag{i1: canString(5)}] = true
+	if !m[GrabBag{i1: canString(5)}] {
+		panic("interface{String() string} not found")
+	}
+	m[GrabBag{a: [4]string{"foo", "bar", "baz", "bop"}}] = true
+	if !m[GrabBag{a: [4]string{"foo", "bar", "baz", "bop"}}] {
+		panic("array not found")
+	}
+}
Index: libgo/go/runtime/type.go
===================================================================
--- libgo/go/runtime/type.go	(revision 279815)
+++ libgo/go/runtime/type.go	(working copy)
@@ -12,18 +12,32 @@  import (
 	"unsafe"
 )
 
+// tflag is documented in reflect/type.go.
+//
+// tflag values must be kept in sync with copies in:
+//	go/types.cc
+//	reflect/type.go
+//      internal/reflectlite/type.go
+type tflag uint8
+
+const (
+	tflagRegularMemory tflag = 1 << 3 // equal and hash can treat values of this type as a single region of t.size bytes
+)
+
 type _type struct {
 	size       uintptr
 	ptrdata    uintptr
 	hash       uint32
-	kind       uint8
-	align      int8
+	tflag      tflag
+	align      uint8
 	fieldAlign uint8
-	_          uint8
-
-	hashfn  func(unsafe.Pointer, uintptr) uintptr
-	equalfn func(unsafe.Pointer, unsafe.Pointer) bool
-
+	kind       uint8
+	// function for comparing objects of this type
+	// (ptr to object A, ptr to object B) -> ==?
+	equal func(unsafe.Pointer, unsafe.Pointer) bool
+	// gcdata stores the GC type data for the garbage collector.
+	// If the KindGCProg bit is set in kind, gcdata is a GC program.
+	// Otherwise it is a ptrmask bitmap. See mbitmap.go for details.
 	gcdata  *byte
 	_string *string
 	*uncommontype
@@ -74,10 +88,12 @@  type interfacetype struct {
 }
 
 type maptype struct {
-	typ        _type
-	key        *_type
-	elem       *_type
-	bucket     *_type // internal type representing a hash bucket
+	typ    _type
+	key    *_type
+	elem   *_type
+	bucket *_type // internal type representing a hash bucket
+	// function for hashing keys (ptr to key, seed) -> hash
+	hasher     func(unsafe.Pointer, uintptr) uintptr
 	keysize    uint8  // size of key slot
 	elemsize   uint8  // size of elem slot
 	bucketsize uint16 // size of bucket
Index: libgo/runtime/go-unsafe-pointer.c
===================================================================
--- libgo/runtime/go-unsafe-pointer.c	(revision 279815)
+++ libgo/runtime/go-unsafe-pointer.c	(working copy)
@@ -36,8 +36,6 @@  static const String reflection_string =
 
 const byte unsafe_Pointer_gc[] = { 1 };
 
-extern const FuncVal runtime_pointerhash_descriptor
-  __asm__ (GOSYM_PREFIX "runtime.pointerhash..f");
 extern const FuncVal runtime_pointerequal_descriptor
   __asm__ (GOSYM_PREFIX "runtime.pointerequal..f");
 
@@ -49,17 +47,15 @@  const struct _type unsafe_Pointer =
   sizeof (void *),
   /* hash */
   78501163U,
-  /* kind */
-  kindUnsafePointer | kindDirectIface,
+  /* tflag */
+  tflagRegularMemory,
   /* align */
   __alignof (void *),
   /* fieldAlign */
   offsetof (struct field_align, p) - 1,
-  /* _ */
-  0,
-  /* hashfn */
-  &runtime_pointerhash_descriptor,
-  /* equalfn */
+  /* kind */
+  kindUnsafePointer | kindDirectIface,
+  /* equal */
   &runtime_pointerequal_descriptor,
   /* gcdata */
   unsafe_Pointer_gc,
@@ -101,16 +97,14 @@  const struct ptrtype pointer_unsafe_Poin
     sizeof (void *),
     /* hash */
     1256018616U,
-    /* kind */
-    kindPtr | kindDirectIface,
+    /* tflag */
+    tflagRegularMemory,
     /* align */
     __alignof (void *),
     /* fieldAlign */
     offsetof (struct field_align, p) - 1,
-    /* _ */
-    0,
-    /*_hashfn */
-    &runtime_pointerhash_descriptor,
+    /* kind */
+    kindPtr | kindDirectIface,
     /* equalfn */
     &runtime_pointerequal_descriptor,
     /* gcdata */