1 /*
2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciMethodType.hpp"
27 #include "ci/ciSignature.hpp"
28 #include "ci/ciUtilities.inline.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "runtime/signature.hpp"
33
34 // ciSignature
35 //
36 // This class represents the signature of a method.
37
38 // ------------------------------------------------------------------
39 // ciSignature::ciSignature
40 ciSignature::ciSignature(ciKlass* accessing_klass, const constantPoolHandle& cpool, ciSymbol* symbol) {
41 ASSERT_IN_VM;
42 EXCEPTION_CONTEXT;
43 _accessing_klass = accessing_klass;
44 _symbol = symbol;
45
46 ciEnv* env = CURRENT_ENV;
47 Arena* arena = env->arena();
48 _types = new (arena) GrowableArray<ciType*>(arena, 8, 0, NULL);
49
50 int size = 0;
51 int count = 0;
52 ResourceMark rm(THREAD);
53 Symbol* sh = symbol->get_symbol();
54 SignatureStream ss(sh);
55 for (; ; ss.next()) {
56 // Process one element of the signature
57 ciType* type;
58 if (!ss.is_object()) {
59 type = ciType::make(ss.type());
60 } else {
61 Symbol* name = ss.as_symbol();
62 ciSymbol* klass_name = env->get_symbol(name);
63 type = env->get_klass_by_name_impl(_accessing_klass, cpool, klass_name, false);
64 }
65 if (type->is_valuetype() && ss.type() == T_VALUETYPE) {
66 type = env->make_never_null_wrapper(type);
67 }
68 _types->append(type);
69 if (ss.at_return_type()) {
70 // Done processing the return type; do not add it into the count.
71 break;
72 }
73 size += type->size();
74 count++;
75 }
76 _size = size;
77 _count = count;
78 }
79
80 // ------------------------------------------------------------------
81 // ciSignature::ciSignature
82 ciSignature::ciSignature(ciKlass* accessing_klass, ciSymbol* symbol, ciMethodType* method_type) :
83 _symbol(symbol),
84 _accessing_klass(accessing_klass),
85 _size( method_type->ptype_slot_count()),
86 _count(method_type->ptype_count())
87 {
88 ASSERT_IN_VM;
89 EXCEPTION_CONTEXT;
90 ciEnv* env = CURRENT_ENV;
91 Arena* arena = env->arena();
92 _types = new (arena) GrowableArray<ciType*>(arena, _count + 1, 0, NULL);
93 ciType* type = NULL;
94 bool never_null = false;
95 for (int i = 0; i < _count; i++) {
96 type = method_type->ptype_at(i, never_null);
97 if (type->is_valuetype() && never_null) {
98 type = env->make_never_null_wrapper(type);
99 }
100 _types->append(type);
101 }
102 type = method_type->rtype(never_null);
103 if (type->is_valuetype() && never_null) {
104 type = env->make_never_null_wrapper(type);
105 }
106 _types->append(type);
107 }
108
109 // ------------------------------------------------------------------
110 // ciSignature::return_type
111 //
112 // What is the return type of this signature?
113 ciType* ciSignature::return_type() const {
114 return _types->at(_count)->unwrap();
115 }
116
117 // ------------------------------------------------------------------
118 // ciSignature::type_at
119 //
120 // What is the type of the index'th element of this
121 // signature?
122 ciType* ciSignature::type_at(int index) const {
123 assert(index < _count, "out of bounds");
124 // The first _klasses element holds the return klass.
125 return _types->at(index)->unwrap();
126 }
127
128 // ------------------------------------------------------------------
129 // ciSignature::return_never_null
130 //
131 // True if we statically know that the return value is never null.
132 bool ciSignature::returns_never_null() const {
133 return _types->at(_count)->is_never_null();
134 }
135
136 // ------------------------------------------------------------------
137 // ciSignature::return_never_null
138 //
139 // True if we statically know that the return value is never null, or
140 // if the return type has a Q signature but is not yet loaded, in which case
141 // it could be a never-null type.
142 bool ciSignature::maybe_returns_never_null() const {
143 ciType* ret_type = _types->at(_count);
144 if (ret_type->is_never_null()) {
145 return true;
146 } else if (ret_type->is_instance_klass() && !ret_type->as_instance_klass()->is_loaded()) {
147 GUARDED_VM_ENTRY(if (get_symbol()->is_Q_method_signature()) { return true; })
148 }
149 return false;
150 }
151
152 // ------------------------------------------------------------------
153 // ciSignature::never_null_at
154 //
155 // True if we statically know that the argument at 'index' is never null.
156 bool ciSignature::is_never_null_at(int index) const {
157 assert(index < _count, "out of bounds");
158 return _types->at(index)->is_never_null();
159 }
160
161 // ------------------------------------------------------------------
162 // ciSignature::equals
163 //
164 // Compare this signature to another one. Signatures with different
165 // accessing classes but with signature-types resolved to the same
166 // types are defined to be equal.
167 bool ciSignature::equals(ciSignature* that) {
168 // Compare signature
169 if (!this->as_symbol()->equals(that->as_symbol())) return false;
170 // Compare all types of the arguments
171 for (int i = 0; i < _count; i++) {
172 if (this->type_at(i) != that->type_at(i)) return false;
173 }
174 // Compare the return type
175 if (this->return_type() != that->return_type()) return false;
176 return true;
177 }
178
179 // ------------------------------------------------------------------
180 // ciSignature::print_signature
181 void ciSignature::print_signature() {
182 _symbol->print_symbol();
183 }
184
185 // ------------------------------------------------------------------
186 // ciSignature::print
187 void ciSignature::print() {
188 tty->print("<ciSignature symbol=");
189 print_signature();
190 tty->print(" accessing_klass=");
191 _accessing_klass->print();
192 tty->print(" address=" INTPTR_FORMAT ">", p2i((address)this));
193 }