hotspot/src/share/vm/classfile/genericSignatures.cpp
changeset 14385 959bbcc16725
child 17024 49cbeca23983
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/classfile/genericSignatures.cpp	Thu Oct 11 12:25:42 2012 -0400
@@ -0,0 +1,1272 @@
+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+
+#include "classfile/genericSignatures.hpp"
+#include "classfile/symbolTable.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "memory/resourceArea.hpp"
+
+namespace generic {
+
+// Helper class for parsing the generic signature Symbol in klass and methods
+class DescriptorStream : public ResourceObj {
+ private:
+  Symbol* _symbol;
+  int _offset;
+  int _mark;
+  const char* _parse_error;
+
+  void set_parse_error(const char* error) {
+    assert(error != NULL, "Can't set NULL error string");
+    _parse_error = error;
+  }
+
+ public:
+  DescriptorStream(Symbol* sym)
+      : _symbol(sym), _offset(0), _mark(-1), _parse_error(NULL) {}
+
+  const char* parse_error() const {
+    return _parse_error;
+  }
+
+  bool at_end() { return _offset >= _symbol->utf8_length(); }
+
+  char peek() {
+    if (at_end()) {
+      set_parse_error("Peeking past end of signature");
+      return '\0';
+    } else {
+      return _symbol->byte_at(_offset);
+    }
+  }
+
+  char read() {
+    if (at_end()) {
+      set_parse_error("Reading past end of signature");
+      return '\0';
+    } else {
+      return _symbol->byte_at(_offset++);
+    }
+  }
+
+  void read(char expected) {
+    char c = read();
+    assert_char(c, expected, 0);
+  }
+
+  void assert_char(char c, char expected, int pos = -1) {
+    if (c != expected) {
+      const char* fmt = "Parse error at %d: expected %c but got %c";
+      size_t len = strlen(fmt) + 5;
+      char* buffer = NEW_RESOURCE_ARRAY(char, len);
+      jio_snprintf(buffer, len, fmt, _offset + pos, expected, c);
+      set_parse_error(buffer);
+    }
+  }
+
+  void push(char c) {
+    assert(c == _symbol->byte_at(_offset - 1), "Pushing back wrong value");
+    --_offset;
+  }
+
+  void expect_end() {
+    if (!at_end()) {
+      set_parse_error("Unexpected data trailing signature");
+    }
+  }
+
+  bool has_mark() { return _mark != -1; }
+
+  void set_mark() {
+    _mark = _offset;
+  }
+
+  Identifier* identifier_from_mark() {
+    assert(has_mark(), "Mark should be set");
+    if (!has_mark()) {
+      set_parse_error("Expected mark to be set");
+      return NULL;
+    } else {
+      Identifier* id = new Identifier(_symbol, _mark, _offset - 1);
+      _mark = -1;
+      return id;
+    }
+  }
+};
+
+
+#define CHECK_FOR_PARSE_ERROR()         \
+  if (STREAM->parse_error() != NULL) {   \
+    if (VerifyGenericSignatures) {      \
+      fatal(STREAM->parse_error());      \
+    }                                   \
+    return NULL;                        \
+  } 0
+
+#define READ() STREAM->read(); CHECK_FOR_PARSE_ERROR()
+#define PEEK() STREAM->peek(); CHECK_FOR_PARSE_ERROR()
+#define PUSH(c) STREAM->push(c)
+#define EXPECT(c) STREAM->read(c); CHECK_FOR_PARSE_ERROR()
+#define EXPECTED(c, ch) STREAM->assert_char(c, ch); CHECK_FOR_PARSE_ERROR()
+#define EXPECT_END() STREAM->expect_end(); CHECK_FOR_PARSE_ERROR()
+
+#define CHECK_STREAM STREAM); CHECK_FOR_PARSE_ERROR(); (0
+
+#ifndef PRODUCT
+void Identifier::print_on(outputStream* str) const {
+  for (int i = _begin; i < _end; ++i) {
+    str->print("%c", (char)_sym->byte_at(i));
+  }
+}
+#endif // ndef PRODUCT
+
+bool Identifier::equals(Identifier* other) {
+  if (_sym == other->_sym && _begin == other->_begin && _end == other->_end) {
+    return true;
+  } else if (_end - _begin != other->_end - other->_begin) {
+    return false;
+  } else {
+    size_t len = _end - _begin;
+    char* addr = ((char*)_sym->bytes()) + _begin;
+    char* oaddr = ((char*)other->_sym->bytes()) + other->_begin;
+    return strncmp(addr, oaddr, len) == 0;
+  }
+}
+
+bool Identifier::equals(Symbol* sym) {
+  Identifier id(sym, 0, sym->utf8_length());
+  return equals(&id);
+}
+
+/**
+ * A formal type parameter may be found in the the enclosing class, but it could
+ * also come from an enclosing method or outer class, in the case of inner-outer
+ * classes or anonymous classes.  For example:
+ *
+ * class Outer<T,V> {
+ *   class Inner<W> {
+ *     void m(T t, V v, W w);
+ *   }
+ * }
+ *
+ * In this case, the type variables in m()'s signature are not all found in the
+ * immediate enclosing class (Inner).  class Inner has only type parameter W,
+ * but it's outer_class field will reference Outer's descriptor which contains
+ * T & V (no outer_method in this case).
+ *
+ * If you have an anonymous class, it has both an enclosing method *and* an
+ * enclosing class where type parameters can be declared:
+ *
+ * class MOuter<T> {
+ *   <V> void bar(V v) {
+ *     Runnable r = new Runnable() {
+ *       public void run() {}
+ *       public void foo(T t, V v) { ... }
+ *     };
+ *   }
+ * }
+ *
+ * In this case, foo will be a member of some class, Runnable$1, which has no
+ * formal parameters itself, but has an outer_method (bar()) which provides
+ * type parameter V, and an outer class MOuter with type parameter T.
+ *
+ * It is also possible that the outer class is itself an inner class to some
+ * other class (or an anonymous class with an enclosing method), so we need to
+ * follow the outer_class/outer_method chain to it's end when looking for a
+ * type parameter.
+ */
+TypeParameter* Descriptor::find_type_parameter(Identifier* id, int* depth) {
+
+  int current_depth = 0;
+
+  MethodDescriptor* outer_method = as_method_signature();
+  ClassDescriptor* outer_class = as_class_signature();
+
+  if (outer_class == NULL) { // 'this' is a method signature; use the holder
+    outer_class = outer_method->outer_class();
+  }
+
+  while (outer_method != NULL || outer_class != NULL) {
+    if (outer_method != NULL) {
+      for (int i = 0; i < outer_method->type_parameters().length(); ++i) {
+        TypeParameter* p = outer_method->type_parameters().at(i);
+        if (p->identifier()->equals(id)) {
+          *depth = -1; // indicates this this is a method parameter
+          return p;
+        }
+      }
+    }
+    if (outer_class != NULL) {
+      for (int i = 0; i < outer_class->type_parameters().length(); ++i) {
+        TypeParameter* p = outer_class->type_parameters().at(i);
+        if (p->identifier()->equals(id)) {
+          *depth = current_depth;
+          return p;
+        }
+      }
+      outer_method = outer_class->outer_method();
+      outer_class = outer_class->outer_class();
+      ++current_depth;
+    }
+  }
+
+  if (VerifyGenericSignatures) {
+    fatal("Could not resolve identifier");
+  }
+
+  return NULL;
+}
+
+ClassDescriptor* ClassDescriptor::parse_generic_signature(Klass* klass, TRAPS) {
+  return parse_generic_signature(klass, NULL, CHECK_NULL);
+}
+
+ClassDescriptor* ClassDescriptor::parse_generic_signature(
+      Klass* klass, Symbol* original_name, TRAPS) {
+
+  InstanceKlass* ik = InstanceKlass::cast(klass);
+  Symbol* sym = ik->generic_signature();
+
+  ClassDescriptor* spec;
+
+  if (sym == NULL || (spec = ClassDescriptor::parse_generic_signature(sym)) == NULL) {
+    spec = ClassDescriptor::placeholder(ik);
+  }
+
+  u2 outer_index = get_outer_class_index(ik, CHECK_NULL);
+  if (outer_index != 0) {
+    if (original_name == NULL) {
+      original_name = ik->name();
+    }
+    Handle class_loader = Handle(THREAD, ik->class_loader());
+    Handle protection_domain = Handle(THREAD, ik->protection_domain());
+
+    Symbol* outer_name = ik->constants()->klass_name_at(outer_index);
+    Klass* outer = SystemDictionary::find(
+        outer_name, class_loader, protection_domain, CHECK_NULL);
+    if (outer == NULL && !THREAD->is_Compiler_thread()) {
+      outer = SystemDictionary::resolve_super_or_fail(original_name,
+          outer_name, class_loader, protection_domain, false, CHECK_NULL);
+    }
+
+    InstanceKlass* outer_ik;
+    ClassDescriptor* outer_spec = NULL;
+    if (outer == NULL) {
+      outer_spec = ClassDescriptor::placeholder(ik);
+      assert(false, "Outer class not loaded and not loadable from here");
+    } else {
+      outer_ik = InstanceKlass::cast(outer);
+      outer_spec = parse_generic_signature(outer, original_name, CHECK_NULL);
+    }
+    spec->set_outer_class(outer_spec);
+
+    u2 encl_method_idx = ik->enclosing_method_method_index();
+    if (encl_method_idx != 0 && outer_ik != NULL) {
+      ConstantPool* cp = ik->constants();
+      u2 name_index = cp->name_ref_index_at(encl_method_idx);
+      u2 sig_index = cp->signature_ref_index_at(encl_method_idx);
+      Symbol* name = cp->symbol_at(name_index);
+      Symbol* sig = cp->symbol_at(sig_index);
+      Method* m = outer_ik->find_method(name, sig);
+      if (m != NULL) {
+        Symbol* gsig = m->generic_signature();
+        if (gsig != NULL) {
+          MethodDescriptor* gms = MethodDescriptor::parse_generic_signature(gsig, outer_spec);
+          spec->set_outer_method(gms);
+        }
+      } else if (VerifyGenericSignatures) {
+        ResourceMark rm;
+        stringStream ss;
+        ss.print("Could not find method %s %s in class %s",
+          name->as_C_string(), sig->as_C_string(), outer_name->as_C_string());
+        fatal(ss.as_string());
+      }
+    }
+  }
+
+  spec->bind_variables_to_parameters();
+  return spec;
+}
+
+ClassDescriptor* ClassDescriptor::placeholder(InstanceKlass* klass) {
+  GrowableArray<TypeParameter*> formals;
+  GrowableArray<ClassType*> interfaces;
+  ClassType* super_type = NULL;
+
+  Klass* super_klass = klass->super();
+  if (super_klass != NULL) {
+    InstanceKlass* super = InstanceKlass::cast(super_klass);
+    super_type = ClassType::from_symbol(super->name());
+  }
+
+  for (int i = 0; i < klass->local_interfaces()->length(); ++i) {
+    InstanceKlass* iface = InstanceKlass::cast(klass->local_interfaces()->at(i));
+    interfaces.append(ClassType::from_symbol(iface->name()));
+  }
+  return new ClassDescriptor(formals, super_type, interfaces);
+}
+
+ClassDescriptor* ClassDescriptor::parse_generic_signature(Symbol* sym) {
+
+  DescriptorStream ds(sym);
+  DescriptorStream* STREAM = &ds;
+
+  GrowableArray<TypeParameter*> parameters(8);
+  char c = READ();
+  if (c == '<') {
+    c = READ();
+    while (c != '>') {
+      PUSH(c);
+      TypeParameter* ftp = TypeParameter::parse_generic_signature(CHECK_STREAM);
+      parameters.append(ftp);
+      c = READ();
+    }
+  } else {
+    PUSH(c);
+  }
+
+  EXPECT('L');
+  ClassType* super = ClassType::parse_generic_signature(CHECK_STREAM);
+
+  GrowableArray<ClassType*> signatures(2);
+  while (!STREAM->at_end()) {
+    EXPECT('L');
+    ClassType* iface = ClassType::parse_generic_signature(CHECK_STREAM);
+    signatures.append(iface);
+  }
+
+  EXPECT_END();
+
+  return new ClassDescriptor(parameters, super, signatures);
+}
+
+#ifndef PRODUCT
+void ClassDescriptor::print_on(outputStream* str) const {
+  str->indent().print_cr("ClassDescriptor {");
+  {
+    streamIndentor si(str);
+    if (_type_parameters.length() > 0) {
+      str->indent().print_cr("Formals {");
+      {
+        streamIndentor si(str);
+        for (int i = 0; i < _type_parameters.length(); ++i) {
+          _type_parameters.at(i)->print_on(str);
+        }
+      }
+      str->indent().print_cr("}");
+    }
+    if (_super != NULL) {
+      str->indent().print_cr("Superclass: ");
+      {
+        streamIndentor si(str);
+        _super->print_on(str);
+      }
+    }
+    if (_interfaces.length() > 0) {
+      str->indent().print_cr("SuperInterfaces: {");
+      {
+        streamIndentor si(str);
+        for (int i = 0; i < _interfaces.length(); ++i) {
+          _interfaces.at(i)->print_on(str);
+        }
+      }
+      str->indent().print_cr("}");
+    }
+    if (_outer_method != NULL) {
+      str->indent().print_cr("Outer Method: {");
+      {
+        streamIndentor si(str);
+        _outer_method->print_on(str);
+      }
+      str->indent().print_cr("}");
+    }
+    if (_outer_class != NULL) {
+      str->indent().print_cr("Outer Class: {");
+      {
+        streamIndentor si(str);
+        _outer_class->print_on(str);
+      }
+      str->indent().print_cr("}");
+    }
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+ClassType* ClassDescriptor::interface_desc(Symbol* sym) {
+  for (int i = 0; i < _interfaces.length(); ++i) {
+    if (_interfaces.at(i)->identifier()->equals(sym)) {
+      return _interfaces.at(i);
+    }
+  }
+  if (VerifyGenericSignatures) {
+    fatal("Did not find expected interface");
+  }
+  return NULL;
+}
+
+void ClassDescriptor::bind_variables_to_parameters() {
+  if (_outer_class != NULL) {
+    _outer_class->bind_variables_to_parameters();
+  }
+  if (_outer_method != NULL) {
+    _outer_method->bind_variables_to_parameters();
+  }
+  for (int i = 0; i < _type_parameters.length(); ++i) {
+    _type_parameters.at(i)->bind_variables_to_parameters(this, i);
+  }
+  if (_super != NULL) {
+    _super->bind_variables_to_parameters(this);
+  }
+  for (int i = 0; i < _interfaces.length(); ++i) {
+    _interfaces.at(i)->bind_variables_to_parameters(this);
+  }
+}
+
+ClassDescriptor* ClassDescriptor::canonicalize(Context* ctx) {
+
+  GrowableArray<TypeParameter*> type_params(_type_parameters.length());
+  for (int i = 0; i < _type_parameters.length(); ++i) {
+    type_params.append(_type_parameters.at(i)->canonicalize(ctx, 0));
+  }
+
+  ClassDescriptor* outer = _outer_class == NULL ? NULL :
+      _outer_class->canonicalize(ctx);
+
+  ClassType* super = _super == NULL ? NULL : _super->canonicalize(ctx, 0);
+
+  GrowableArray<ClassType*> interfaces(_interfaces.length());
+  for (int i = 0; i < _interfaces.length(); ++i) {
+    interfaces.append(_interfaces.at(i)->canonicalize(ctx, 0));
+  }
+
+  MethodDescriptor* md = _outer_method == NULL ? NULL :
+      _outer_method->canonicalize(ctx);
+
+  return new ClassDescriptor(type_params, super, interfaces, outer, md);
+}
+
+u2 ClassDescriptor::get_outer_class_index(InstanceKlass* klass, TRAPS) {
+  int inner_index = InstanceKlass::inner_class_inner_class_info_offset;
+  int outer_index = InstanceKlass::inner_class_outer_class_info_offset;
+  int name_offset = InstanceKlass::inner_class_inner_name_offset;
+  int next_offset = InstanceKlass::inner_class_next_offset;
+
+  if (klass->inner_classes() == NULL || klass->inner_classes()->length() == 0) {
+    // No inner class info => no declaring class
+    return 0;
+  }
+
+  Array<u2>* i_icls = klass->inner_classes();
+  ConstantPool* i_cp = klass->constants();
+  int i_length = i_icls->length();
+
+  // Find inner_klass attribute
+  for (int i = 0; i + next_offset < i_length; i += next_offset) {
+    u2 ioff = i_icls->at(i + inner_index);
+    u2 ooff = i_icls->at(i + outer_index);
+    u2 noff = i_icls->at(i + name_offset);
+    if (ioff != 0) {
+      // Check to see if the name matches the class we're looking for
+      // before attempting to find the class.
+      if (i_cp->klass_name_at_matches(klass, ioff) && ooff != 0) {
+        return ooff;
+      }
+    }
+  }
+
+  // It may be anonymous; try for that.
+  u2 encl_method_class_idx = klass->enclosing_method_class_index();
+  if (encl_method_class_idx != 0) {
+    return encl_method_class_idx;
+  }
+
+  return 0;
+}
+
+MethodDescriptor* MethodDescriptor::parse_generic_signature(Method* m, ClassDescriptor* outer) {
+  Symbol* generic_sig = m->generic_signature();
+  MethodDescriptor* md = NULL;
+  if (generic_sig == NULL || (md = parse_generic_signature(generic_sig, outer)) == NULL) {
+    md = parse_generic_signature(m->signature(), outer);
+  }
+  assert(md != NULL, "Could not parse method signature");
+  md->bind_variables_to_parameters();
+  return md;
+}
+
+MethodDescriptor* MethodDescriptor::parse_generic_signature(Symbol* sym, ClassDescriptor* outer) {
+
+  DescriptorStream ds(sym);
+  DescriptorStream* STREAM = &ds;
+
+  GrowableArray<TypeParameter*> params(8);
+  char c = READ();
+  if (c == '<') {
+    c = READ();
+    while (c != '>') {
+      PUSH(c);
+      TypeParameter* ftp = TypeParameter::parse_generic_signature(CHECK_STREAM);
+      params.append(ftp);
+      c = READ();
+    }
+  } else {
+    PUSH(c);
+  }
+
+  EXPECT('(');
+
+  GrowableArray<Type*> parameters(8);
+  c = READ();
+  while (c != ')') {
+    PUSH(c);
+    Type* arg = Type::parse_generic_signature(CHECK_STREAM);
+    parameters.append(arg);
+    c = READ();
+  }
+
+  Type* rt = Type::parse_generic_signature(CHECK_STREAM);
+
+  GrowableArray<Type*> throws;
+  while (!STREAM->at_end()) {
+    EXPECT('^');
+    Type* spec = Type::parse_generic_signature(CHECK_STREAM);
+    throws.append(spec);
+  }
+
+  return new MethodDescriptor(params, outer, parameters, rt, throws);
+}
+
+void MethodDescriptor::bind_variables_to_parameters() {
+  for (int i = 0; i < _type_parameters.length(); ++i) {
+    _type_parameters.at(i)->bind_variables_to_parameters(this, i);
+  }
+  for (int i = 0; i < _parameters.length(); ++i) {
+    _parameters.at(i)->bind_variables_to_parameters(this);
+  }
+  _return_type->bind_variables_to_parameters(this);
+  for (int i = 0; i < _throws.length(); ++i) {
+    _throws.at(i)->bind_variables_to_parameters(this);
+  }
+}
+
+bool MethodDescriptor::covariant_match(MethodDescriptor* other, Context* ctx) {
+
+  if (_parameters.length() == other->_parameters.length()) {
+    for (int i = 0; i < _parameters.length(); ++i) {
+      if (!_parameters.at(i)->covariant_match(other->_parameters.at(i), ctx)) {
+        return false;
+      }
+    }
+
+    if (_return_type->as_primitive() != NULL) {
+      return _return_type->covariant_match(other->_return_type, ctx);
+    } else {
+      // return type is a reference
+      return other->_return_type->as_class() != NULL ||
+             other->_return_type->as_variable() != NULL ||
+             other->_return_type->as_array() != NULL;
+    }
+  } else {
+    return false;
+  }
+}
+
+MethodDescriptor* MethodDescriptor::canonicalize(Context* ctx) {
+
+  GrowableArray<TypeParameter*> type_params(_type_parameters.length());
+  for (int i = 0; i < _type_parameters.length(); ++i) {
+    type_params.append(_type_parameters.at(i)->canonicalize(ctx, 0));
+  }
+
+  ClassDescriptor* outer = _outer_class == NULL ? NULL :
+      _outer_class->canonicalize(ctx);
+
+  GrowableArray<Type*> params(_parameters.length());
+  for (int i = 0; i < _parameters.length(); ++i) {
+    params.append(_parameters.at(i)->canonicalize(ctx, 0));
+  }
+
+  Type* rt = _return_type->canonicalize(ctx, 0);
+
+  GrowableArray<Type*> throws(_throws.length());
+  for (int i = 0; i < _throws.length(); ++i) {
+    throws.append(_throws.at(i)->canonicalize(ctx, 0));
+  }
+
+  return new MethodDescriptor(type_params, outer, params, rt, throws);
+}
+
+#ifndef PRODUCT
+TempNewSymbol MethodDescriptor::reify_signature(Context* ctx, TRAPS) {
+  stringStream ss(256);
+
+  ss.print("(");
+  for (int i = 0; i < _parameters.length(); ++i) {
+    _parameters.at(i)->reify_signature(&ss, ctx);
+  }
+  ss.print(")");
+  _return_type->reify_signature(&ss, ctx);
+  return SymbolTable::new_symbol(ss.base(), (int)ss.size(), THREAD);
+}
+
+void MethodDescriptor::print_on(outputStream* str) const {
+  str->indent().print_cr("MethodDescriptor {");
+  {
+    streamIndentor si(str);
+    if (_type_parameters.length() > 0) {
+      str->indent().print_cr("Formals: {");
+      {
+        streamIndentor si(str);
+        for (int i = 0; i < _type_parameters.length(); ++i) {
+          _type_parameters.at(i)->print_on(str);
+        }
+      }
+      str->indent().print_cr("}");
+    }
+    str->indent().print_cr("Parameters: {");
+    {
+      streamIndentor si(str);
+      for (int i = 0; i < _parameters.length(); ++i) {
+        _parameters.at(i)->print_on(str);
+      }
+    }
+    str->indent().print_cr("}");
+    str->indent().print_cr("Return Type: ");
+    {
+      streamIndentor si(str);
+      _return_type->print_on(str);
+    }
+
+    if (_throws.length() > 0) {
+      str->indent().print_cr("Throws: {");
+      {
+        streamIndentor si(str);
+        for (int i = 0; i < _throws.length(); ++i) {
+          _throws.at(i)->print_on(str);
+        }
+      }
+      str->indent().print_cr("}");
+    }
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+TypeParameter* TypeParameter::parse_generic_signature(DescriptorStream* STREAM) {
+  STREAM->set_mark();
+  char c = READ();
+  while (c != ':') {
+    c = READ();
+  }
+
+  Identifier* id = STREAM->identifier_from_mark();
+
+  ClassType* class_bound = NULL;
+  GrowableArray<ClassType*> interface_bounds(8);
+
+  c = READ();
+  if (c != '>') {
+    if (c != ':') {
+      EXPECTED(c, 'L');
+      class_bound = ClassType::parse_generic_signature(CHECK_STREAM);
+      c = READ();
+    }
+
+    while (c == ':') {
+      EXPECT('L');
+      ClassType* fts = ClassType::parse_generic_signature(CHECK_STREAM);
+      interface_bounds.append(fts);
+      c = READ();
+    }
+  }
+  PUSH(c);
+
+  return new TypeParameter(id, class_bound, interface_bounds);
+}
+
+void TypeParameter::bind_variables_to_parameters(Descriptor* sig, int position) {
+  if (_class_bound != NULL) {
+    _class_bound->bind_variables_to_parameters(sig);
+  }
+  for (int i = 0; i < _interface_bounds.length(); ++i) {
+    _interface_bounds.at(i)->bind_variables_to_parameters(sig);
+  }
+  _position = position;
+}
+
+Type* TypeParameter::resolve(
+    Context* ctx, int inner_depth, int ctx_depth) {
+
+  if (inner_depth == -1) {
+    // This indicates that the parameter is a method type parameter, which
+    // isn't resolveable using the class hierarchy context
+    return bound();
+  }
+
+  ClassType* provider = ctx->at_depth(ctx_depth);
+  if (provider != NULL) {
+    for (int i = 0; i < inner_depth && provider != NULL; ++i) {
+      provider = provider->outer_class();
+    }
+    if (provider != NULL) {
+      TypeArgument* arg = provider->type_argument_at(_position);
+      if (arg != NULL) {
+        Type* value = arg->lower_bound();
+        return value->canonicalize(ctx, ctx_depth + 1);
+      }
+    }
+  }
+
+  return bound();
+}
+
+TypeParameter* TypeParameter::canonicalize(Context* ctx, int ctx_depth) {
+  ClassType* bound = _class_bound == NULL ? NULL :
+     _class_bound->canonicalize(ctx, ctx_depth);
+
+  GrowableArray<ClassType*> ifaces(_interface_bounds.length());
+  for (int i = 0; i < _interface_bounds.length(); ++i) {
+    ifaces.append(_interface_bounds.at(i)->canonicalize(ctx, ctx_depth));
+  }
+
+  TypeParameter* ret = new TypeParameter(_identifier, bound, ifaces);
+  ret->_position = _position;
+  return ret;
+}
+
+ClassType* TypeParameter::bound() {
+  if (_class_bound != NULL) {
+    return _class_bound;
+  }
+
+  if (_interface_bounds.length() == 1) {
+    return _interface_bounds.at(0);
+  }
+
+  return ClassType::java_lang_Object(); // TODO: investigate this case
+}
+
+#ifndef PRODUCT
+void TypeParameter::print_on(outputStream* str) const {
+  str->indent().print_cr("Formal: {");
+  {
+    streamIndentor si(str);
+
+    str->indent().print("Identifier: ");
+    _identifier->print_on(str);
+    str->print_cr("");
+    if (_class_bound != NULL) {
+      str->indent().print_cr("Class Bound: ");
+      streamIndentor si(str);
+      _class_bound->print_on(str);
+    }
+    if (_interface_bounds.length() > 0) {
+      str->indent().print_cr("Interface Bounds: {");
+      {
+        streamIndentor si(str);
+        for (int i = 0; i < _interface_bounds.length(); ++i) {
+          _interface_bounds.at(i)->print_on(str);
+        }
+      }
+      str->indent().print_cr("}");
+    }
+    str->indent().print_cr("Ordinal Position: %d", _position);
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+Type* Type::parse_generic_signature(DescriptorStream* STREAM) {
+  char c = READ();
+  switch (c) {
+    case 'L':
+      return ClassType::parse_generic_signature(CHECK_STREAM);
+    case 'T':
+      return TypeVariable::parse_generic_signature(CHECK_STREAM);
+    case '[':
+      return ArrayType::parse_generic_signature(CHECK_STREAM);
+    default:
+      return new PrimitiveType(c);
+  }
+}
+
+Identifier* ClassType::parse_generic_signature_simple(GrowableArray<TypeArgument*>* args,
+    bool* has_inner, DescriptorStream* STREAM) {
+  STREAM->set_mark();
+
+  char c = READ();
+  while (c != ';' && c != '.' && c != '<') { c = READ(); }
+  Identifier* id = STREAM->identifier_from_mark();
+
+  if (c == '<') {
+    c = READ();
+    while (c != '>') {
+      PUSH(c);
+      TypeArgument* arg = TypeArgument::parse_generic_signature(CHECK_STREAM);
+      args->append(arg);
+      c = READ();
+    }
+    c = READ();
+  }
+
+  *has_inner = (c == '.');
+  if (!(*has_inner)) {
+    EXPECTED(c, ';');
+  }
+
+  return id;
+}
+
+ClassType* ClassType::parse_generic_signature(DescriptorStream* STREAM) {
+  return parse_generic_signature(NULL, CHECK_STREAM);
+}
+
+ClassType* ClassType::parse_generic_signature(ClassType* outer, DescriptorStream* STREAM) {
+  GrowableArray<TypeArgument*> args;
+  ClassType* gct = NULL;
+  bool has_inner = false;
+
+  Identifier* id = parse_generic_signature_simple(&args, &has_inner, STREAM);
+  if (id != NULL) {
+    gct = new ClassType(id, args, outer);
+
+    if (has_inner) {
+      gct = parse_generic_signature(gct, CHECK_STREAM);
+    }
+  }
+  return gct;
+}
+
+ClassType* ClassType::from_symbol(Symbol* sym) {
+  assert(sym != NULL, "Must not be null");
+  GrowableArray<TypeArgument*> args;
+  Identifier* id = new Identifier(sym, 0, sym->utf8_length());
+  return new ClassType(id, args, NULL);
+}
+
+ClassType* ClassType::java_lang_Object() {
+  return from_symbol(vmSymbols::java_lang_Object());
+}
+
+void ClassType::bind_variables_to_parameters(Descriptor* sig) {
+  for (int i = 0; i < _type_arguments.length(); ++i) {
+    _type_arguments.at(i)->bind_variables_to_parameters(sig);
+  }
+  if (_outer_class != NULL) {
+    _outer_class->bind_variables_to_parameters(sig);
+  }
+}
+
+TypeArgument* ClassType::type_argument_at(int i) {
+  if (i >= 0 && i < _type_arguments.length()) {
+    return _type_arguments.at(i);
+  } else {
+    return NULL;
+  }
+}
+
+#ifndef PRODUCT
+void ClassType::reify_signature(stringStream* ss, Context* ctx) {
+  ss->print("L");
+  _identifier->print_on(ss);
+  ss->print(";");
+}
+
+void ClassType::print_on(outputStream* str) const {
+  str->indent().print_cr("Class {");
+  {
+    streamIndentor si(str);
+    str->indent().print("Name: ");
+    _identifier->print_on(str);
+    str->print_cr("");
+    if (_type_arguments.length() != 0) {
+      str->indent().print_cr("Type Arguments: {");
+      {
+        streamIndentor si(str);
+        for (int j = 0; j < _type_arguments.length(); ++j) {
+          _type_arguments.at(j)->print_on(str);
+        }
+      }
+      str->indent().print_cr("}");
+    }
+    if (_outer_class != NULL) {
+      str->indent().print_cr("Outer Class: ");
+      streamIndentor sir(str);
+      _outer_class->print_on(str);
+    }
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+bool ClassType::covariant_match(Type* other, Context* ctx) {
+
+  if (other == this) {
+    return true;
+  }
+
+  TypeVariable* variable = other->as_variable();
+  if (variable != NULL) {
+    other = variable->resolve(ctx, 0);
+  }
+
+  ClassType* outer = outer_class();
+  ClassType* other_class = other->as_class();
+
+  if (other_class == NULL ||
+      (outer == NULL) != (other_class->outer_class() == NULL)) {
+    return false;
+  }
+
+  if (!_identifier->equals(other_class->_identifier)) {
+    return false;
+  }
+
+  if (outer != NULL && !outer->covariant_match(other_class->outer_class(), ctx)) {
+    return false;
+  }
+
+  return true;
+}
+
+ClassType* ClassType::canonicalize(Context* ctx, int ctx_depth) {
+
+  GrowableArray<TypeArgument*> args(_type_arguments.length());
+  for (int i = 0; i < _type_arguments.length(); ++i) {
+    args.append(_type_arguments.at(i)->canonicalize(ctx, ctx_depth));
+  }
+
+  ClassType* outer = _outer_class == NULL ? NULL :
+      _outer_class->canonicalize(ctx, ctx_depth);
+
+  return new ClassType(_identifier, args, outer);
+}
+
+TypeVariable* TypeVariable::parse_generic_signature(DescriptorStream* STREAM) {
+  STREAM->set_mark();
+  char c = READ();
+  while (c != ';') {
+    c = READ();
+  }
+  Identifier* id = STREAM->identifier_from_mark();
+
+  return new TypeVariable(id);
+}
+
+void TypeVariable::bind_variables_to_parameters(Descriptor* sig) {
+  _parameter = sig->find_type_parameter(_id, &_inner_depth);
+  if (VerifyGenericSignatures && _parameter == NULL) {
+    fatal("Could not find formal parameter");
+  }
+}
+
+Type* TypeVariable::resolve(Context* ctx, int ctx_depth) {
+  if (parameter() != NULL) {
+    return parameter()->resolve(ctx, inner_depth(), ctx_depth);
+  } else {
+    if (VerifyGenericSignatures) {
+      fatal("Type variable matches no parameter");
+    }
+    return NULL;
+  }
+}
+
+bool TypeVariable::covariant_match(Type* other, Context* ctx) {
+
+  if (other == this) {
+    return true;
+  }
+
+  Context my_context(NULL); // empty, results in erasure
+  Type* my_type = resolve(&my_context, 0);
+  if (my_type == NULL) {
+    return false;
+  }
+
+  return my_type->covariant_match(other, ctx);
+}
+
+Type* TypeVariable::canonicalize(Context* ctx, int ctx_depth) {
+  return resolve(ctx, ctx_depth);
+}
+
+#ifndef PRODUCT
+void TypeVariable::reify_signature(stringStream* ss, Context* ctx) {
+  Type* type = resolve(ctx, 0);
+  if (type != NULL) {
+    type->reify_signature(ss, ctx);
+  }
+}
+
+void TypeVariable::print_on(outputStream* str) const {
+  str->indent().print_cr("Type Variable {");
+  {
+    streamIndentor si(str);
+    str->indent().print("Name: ");
+    _id->print_on(str);
+    str->print_cr("");
+    str->indent().print_cr("Inner depth: %d", _inner_depth);
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+ArrayType* ArrayType::parse_generic_signature(DescriptorStream* STREAM) {
+  Type* base = Type::parse_generic_signature(CHECK_STREAM);
+  return new ArrayType(base);
+}
+
+void ArrayType::bind_variables_to_parameters(Descriptor* sig) {
+  assert(_base != NULL, "Invalid base");
+  _base->bind_variables_to_parameters(sig);
+}
+
+bool ArrayType::covariant_match(Type* other, Context* ctx) {
+  assert(_base != NULL, "Invalid base");
+
+  if (other == this) {
+    return true;
+  }
+
+  ArrayType* other_array = other->as_array();
+  return (other_array != NULL && _base->covariant_match(other_array->_base, ctx));
+}
+
+ArrayType* ArrayType::canonicalize(Context* ctx, int ctx_depth) {
+  assert(_base != NULL, "Invalid base");
+  return new ArrayType(_base->canonicalize(ctx, ctx_depth));
+}
+
+#ifndef PRODUCT
+void ArrayType::reify_signature(stringStream* ss, Context* ctx) {
+  assert(_base != NULL, "Invalid base");
+  ss->print("[");
+  _base->reify_signature(ss, ctx);
+}
+
+void ArrayType::print_on(outputStream* str) const {
+  str->indent().print_cr("Array {");
+  {
+    streamIndentor si(str);
+    _base->print_on(str);
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+bool PrimitiveType::covariant_match(Type* other, Context* ctx) {
+
+  PrimitiveType* other_prim = other->as_primitive();
+  return (other_prim != NULL && _type == other_prim->_type);
+}
+
+PrimitiveType* PrimitiveType::canonicalize(Context* ctx, int ctxd) {
+  return this;
+}
+
+#ifndef PRODUCT
+void PrimitiveType::reify_signature(stringStream* ss, Context* ctx) {
+  ss->print("%c", _type);
+}
+
+void PrimitiveType::print_on(outputStream* str) const {
+  str->indent().print_cr("Primitive: '%c'", _type);
+}
+#endif // ndef PRODUCT
+
+void PrimitiveType::bind_variables_to_parameters(Descriptor* sig) {
+}
+
+TypeArgument* TypeArgument::parse_generic_signature(DescriptorStream* STREAM) {
+  char c = READ();
+  Type* type = NULL;
+
+  switch (c) {
+    case '*':
+      return new TypeArgument(ClassType::java_lang_Object(), NULL);
+      break;
+    default:
+      PUSH(c);
+      // fall-through
+    case '+':
+    case '-':
+      type = Type::parse_generic_signature(CHECK_STREAM);
+      if (c == '+') {
+        return new TypeArgument(type, NULL);
+      } else if (c == '-') {
+        return new TypeArgument(ClassType::java_lang_Object(), type);
+      } else {
+        return new TypeArgument(type, type);
+      }
+  }
+}
+
+void TypeArgument::bind_variables_to_parameters(Descriptor* sig) {
+  assert(_lower_bound != NULL, "Invalid lower bound");
+  _lower_bound->bind_variables_to_parameters(sig);
+  if (_upper_bound != NULL && _upper_bound != _lower_bound) {
+    _upper_bound->bind_variables_to_parameters(sig);
+  }
+}
+
+bool TypeArgument::covariant_match(TypeArgument* other, Context* ctx) {
+  assert(_lower_bound != NULL, "Invalid lower bound");
+
+  if (other == this) {
+    return true;
+  }
+
+  if (!_lower_bound->covariant_match(other->lower_bound(), ctx)) {
+    return false;
+  }
+  return true;
+}
+
+TypeArgument* TypeArgument::canonicalize(Context* ctx, int ctx_depth) {
+  assert(_lower_bound != NULL, "Invalid lower bound");
+  Type* lower = _lower_bound->canonicalize(ctx, ctx_depth);
+  Type* upper = NULL;
+
+  if (_upper_bound == _lower_bound) {
+    upper = lower;
+  } else if (_upper_bound != NULL) {
+    upper = _upper_bound->canonicalize(ctx, ctx_depth);
+  }
+
+  return new TypeArgument(lower, upper);
+}
+
+#ifndef PRODUCT
+void TypeArgument::print_on(outputStream* str) const {
+  str->indent().print_cr("TypeArgument {");
+  {
+    streamIndentor si(str);
+    if (_lower_bound != NULL) {
+      str->indent().print("Lower bound: ");
+      _lower_bound->print_on(str);
+    }
+    if (_upper_bound != NULL) {
+      str->indent().print("Upper bound: ");
+      _upper_bound->print_on(str);
+    }
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+void Context::Mark::destroy() {
+  if (is_active()) {
+    _context->reset_to_mark(_marked_size);
+  }
+  deactivate();
+}
+
+void Context::apply_type_arguments(
+    InstanceKlass* current, InstanceKlass* super, TRAPS) {
+  assert(_cache != NULL, "Cannot use an empty context");
+  ClassType* spec = NULL;
+  if (current != NULL) {
+    ClassDescriptor* descriptor = _cache->descriptor_for(current, CHECK);
+    if (super == current->super()) {
+      spec = descriptor->super();
+    } else {
+      spec = descriptor->interface_desc(super->name());
+    }
+    if (spec != NULL) {
+      _type_arguments.push(spec);
+    }
+  }
+}
+
+void Context::reset_to_mark(int size) {
+  _type_arguments.trunc_to(size);
+}
+
+ClassType* Context::at_depth(int i) const {
+  if (i < _type_arguments.length()) {
+    return _type_arguments.at(_type_arguments.length() - 1 - i);
+  }
+  return NULL;
+}
+
+#ifndef PRODUCT
+void Context::print_on(outputStream* str) const {
+  str->indent().print_cr("Context {");
+  for (int i = 0; i < _type_arguments.length(); ++i) {
+    streamIndentor si(str);
+    str->indent().print("leval %d: ", i);
+    ClassType* ct = at_depth(i);
+    if (ct == NULL) {
+      str->print_cr("<empty>");
+      continue;
+    } else {
+      str->print_cr("{");
+    }
+
+    for (int j = 0; j < ct->type_arguments_length(); ++j) {
+      streamIndentor si(str);
+      TypeArgument* ta = ct->type_argument_at(j);
+      Type* bound = ta->lower_bound();
+      bound->print_on(str);
+    }
+    str->indent().print_cr("}");
+  }
+  str->indent().print_cr("}");
+}
+#endif // ndef PRODUCT
+
+ClassDescriptor* DescriptorCache::descriptor_for(InstanceKlass* ik, TRAPS) {
+
+  ClassDescriptor** existing = _class_descriptors.get(ik);
+  if (existing == NULL) {
+    ClassDescriptor* cd = ClassDescriptor::parse_generic_signature(ik, CHECK_NULL);
+    _class_descriptors.put(ik, cd);
+    return cd;
+  } else {
+    return *existing;
+  }
+}
+
+MethodDescriptor* DescriptorCache::descriptor_for(
+    Method* mh, ClassDescriptor* cd, TRAPS) {
+  assert(mh != NULL && cd != NULL, "Should not be NULL");
+  MethodDescriptor** existing = _method_descriptors.get(mh);
+  if (existing == NULL) {
+    MethodDescriptor* md = MethodDescriptor::parse_generic_signature(mh, cd);
+    _method_descriptors.put(mh, md);
+    return md;
+  } else {
+    return *existing;
+  }
+}
+MethodDescriptor* DescriptorCache::descriptor_for(Method* mh, TRAPS) {
+  ClassDescriptor* cd = descriptor_for(
+      InstanceKlass::cast(mh->method_holder()), CHECK_NULL);
+  return descriptor_for(mh, cd, THREAD);
+}
+
+} // namespace generic