1 /*
2 * Copyright (c) 2019, 2026, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
24
25 #include "classfile/javaClasses.inline.hpp"
26 #include "classfile/resolutionErrors.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmClasses.hpp"
29 #include "interpreter/bootstrapInfo.hpp"
30 #include "interpreter/linkResolver.hpp"
31 #include "jvm.h"
32 #include "logging/log.hpp"
33 #include "logging/logStream.hpp"
34 #include "memory/oopFactory.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/constantPool.inline.hpp"
37 #include "oops/cpCache.inline.hpp"
38 #include "oops/objArrayOop.inline.hpp"
39 #include "oops/oopCast.inline.hpp"
40 #include "oops/resolvedIndyEntry.hpp"
41 #include "oops/typeArrayOop.inline.hpp"
42 #include "runtime/handles.inline.hpp"
43 #include "runtime/javaThread.hpp"
44 #include "runtime/vmThread.hpp"
45
46 //------------------------------------------------------------------------------------------------------------------------
47 // Implementation of BootstrapInfo
48
49 BootstrapInfo::BootstrapInfo(const constantPoolHandle& pool, int bss_index, int indy_index)
50 : _pool(pool),
51 _bss_index(bss_index),
52 _indy_index(indy_index),
53 // derived and eagerly cached:
54 _argc( pool->bootstrap_argument_count_at(bss_index) ),
55 _name( pool->uncached_name_ref_at(bss_index) ),
56 _signature( pool->uncached_signature_ref_at(bss_index) )
57 {
58 _is_resolved = false;
59 assert(pool->tag_at(bss_index).has_bootstrap(), "");
60 assert(indy_index == -1 || pool->resolved_indy_entry_at(indy_index)->constant_pool_index() == bss_index, "invalid bootstrap specifier index");
61 }
62
63 // If there is evidence this call site was already linked, set the
64 // existing linkage data into result, or throw previous exception.
65 // Return true if either action is taken, else false.
66 bool BootstrapInfo::resolve_previously_linked_invokedynamic(CallInfo& result, TRAPS) {
67 assert(_indy_index != -1, "");
68 // Check if method is not null
69 ResolvedIndyEntry* indy_entry = _pool->resolved_indy_entry_at(_indy_index);
70 if (indy_entry->method() != nullptr) {
71 methodHandle method(THREAD, indy_entry->method());
72 Handle appendix(THREAD, _pool->resolved_reference_from_indy(_indy_index));
73 result.set_handle(vmClasses::MethodHandle_klass(), method, appendix, THREAD);
74 Exceptions::wrap_dynamic_exception(/* is_indy */ true, CHECK_false);
75 return true;
76 } else if (indy_entry->resolution_failed()) {
77 int encoded_index = ResolutionErrorTable::encode_indy_index(_indy_index);
78 ConstantPool::throw_resolution_error(_pool, encoded_index, CHECK_false); // Doesn't necessarily need to be resolved yet
79 return true;
80 } else {
81 return false;
82 }
83 }
84
85 // Resolve the bootstrap specifier in 3 steps:
86 // - unpack the BSM by resolving the MH constant
87 // - obtain the NameAndType description for the condy/indy
88 // - prepare the BSM's static arguments
89 Handle BootstrapInfo::resolve_bsm(TRAPS) {
90 if (_bsm.not_null()) {
91 return _bsm;
92 }
93
94 bool is_indy = is_method_call();
95 // The tag at the bootstrap method index must be a valid method handle or a method handle in error.
96 // If it is a MethodHandleInError, a resolution error will be thrown which will be wrapped if necessary
97 // with a BootstrapMethodError.
98 assert(_pool->tag_at(bsm_index()).is_method_handle() ||
99 _pool->tag_at(bsm_index()).is_method_handle_in_error(), "MH not present, classfile structural constraint");
100 oop bsm_oop = _pool->resolve_possibly_cached_constant_at(bsm_index(), THREAD);
101 Exceptions::wrap_dynamic_exception(is_indy, CHECK_NH);
102 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm_oop), "classfile must supply a valid BSM");
103 _bsm = Handle(THREAD, bsm_oop);
104
105 // Obtain NameAndType information
106 resolve_bss_name_and_type(THREAD);
107 Exceptions::wrap_dynamic_exception(is_indy, CHECK_NH);
108
109 // Prepare static arguments
110 resolve_args(THREAD);
111 Exceptions::wrap_dynamic_exception(is_indy, CHECK_NH);
112
113 return _bsm;
114 }
115
116 // Resolve metadata from the JVM_Dynamic_info or JVM_InvokeDynamic_info's name and type information.
117 void BootstrapInfo::resolve_bss_name_and_type(TRAPS) {
118 assert(_bsm.not_null(), "resolve_bsm first");
119 Symbol* name = this->name();
120 Symbol* type = this->signature();
121 _name_arg = java_lang_String::create_from_symbol(name, CHECK);
122 if (type->char_at(0) == '(') {
123 _type_arg = SystemDictionary::find_method_handle_type(type, caller(), CHECK);
124 } else {
125 _type_arg = SystemDictionary::find_java_mirror_for_type(type, caller(), SignatureStream::NCDFError, CHECK);
126 }
127 }
128
129 // Resolve the bootstrap method's static arguments and store the result in _arg_values.
130 void BootstrapInfo::resolve_args(TRAPS) {
131 assert(_bsm.not_null(), "resolve_bsm first");
132
133 // if there are no static arguments, return leaving _arg_values as null
134 if (_argc == 0 && UseBootstrapCallInfo < 2) return;
135
136 bool use_BSCI;
137 switch (UseBootstrapCallInfo) {
138 default: use_BSCI = true; break; // stress mode
139 case 0: use_BSCI = false; break; // stress mode
140 case 1: // normal mode
141 // If we were to support an alternative mode of BSM invocation,
142 // we'd convert to pull mode here if the BSM could be a candidate
143 // for that alternative mode. We can't easily test for things
144 // like varargs here, but we can get away with approximate testing,
145 // since the JDK runtime will make up the difference either way.
146 // For now, exercise the pull-mode path if the BSM is of arity 2,
147 // or if there is a potential condy loop (see below).
148 oop mt_oop = java_lang_invoke_MethodHandle::type(_bsm());
149 use_BSCI = (java_lang_invoke_MethodType::ptype_count(mt_oop) == 2);
150 break;
151 }
152
153 // Here's a reason to use BSCI even if it wasn't requested:
154 // If a condy uses a condy argument, we want to avoid infinite
155 // recursion (condy loops) in the C code. It's OK in Java,
156 // because Java has stack overflow checking, so we punt
157 // potentially cyclic cases from C to Java.
158 if (!use_BSCI && _pool->tag_at(_bss_index).is_dynamic_constant()) {
159 bool found_unresolved_condy = false;
160 for (int i = 0; i < _argc; i++) {
161 int arg_index = _pool->bootstrap_argument_index_at(_bss_index, i);
162 if (_pool->tag_at(arg_index).is_dynamic_constant()) {
163 // potential recursion point condy -> condy
164 bool found_it = false;
165 _pool->find_cached_constant_at(arg_index, found_it, CHECK);
166 if (!found_it) { found_unresolved_condy = true; break; }
167 }
168 }
169 if (found_unresolved_condy)
170 use_BSCI = true;
171 }
172
173 const int SMALL_ARITY = 5;
174 if (use_BSCI && _argc <= SMALL_ARITY && UseBootstrapCallInfo <= 2) {
175 // If there are only a few arguments, and none of them need linking,
176 // push them, instead of asking the JDK runtime to turn around and
177 // pull them, saving a JVM/JDK transition in some simple cases.
178 bool all_resolved = true;
179 for (int i = 0; i < _argc; i++) {
180 bool found_it = false;
181 int arg_index = _pool->bootstrap_argument_index_at(_bss_index, i);
182 _pool->find_cached_constant_at(arg_index, found_it, CHECK);
183 if (!found_it) { all_resolved = false; break; }
184 }
185 if (all_resolved)
186 use_BSCI = false;
187 }
188
189 if (!use_BSCI) {
190 // return {arg...}; resolution of arguments is done immediately, before JDK code is called
191 refArrayOop args_oop = oopFactory::new_refArray(vmClasses::Object_klass(),_argc, CHECK);
192 refArrayHandle args(THREAD, args_oop);
193 _pool->copy_bootstrap_arguments_at(_bss_index, 0, _argc, args, 0, true, Handle(), CHECK);
194 oop arg_oop = ((_argc == 1) ? args->obj_at(0) : (oop)nullptr);
195 // try to discard the singleton array
196 if (arg_oop != nullptr && !arg_oop->is_array()) {
197 // JVM treats arrays and nulls specially in this position,
198 // but other things are just single arguments
199 _arg_values = Handle(THREAD, arg_oop);
200 } else {
201 _arg_values = args;
202 }
203 } else {
204 // return {arg_count, pool_index}; JDK code must pull the arguments as needed
205 typeArrayOop ints_oop = oopFactory::new_typeArray(T_INT, 2, CHECK);
206 ints_oop->int_at_put(0, _argc);
207 ints_oop->int_at_put(1, _bss_index);
208 _arg_values = Handle(THREAD, ints_oop);
209 }
210 }
211
212 // there must be a LinkageError pending; try to save it and then throw
213 bool BootstrapInfo::save_and_throw_indy_exc(TRAPS) {
214 assert(HAS_PENDING_EXCEPTION, "");
215 assert(_indy_index != -1, "");
216 assert(_indy_index >= 0, "Indy index must be decoded by now");
217 bool recorded_res_status = _pool->cache()->save_and_throw_indy_exc(_pool, _bss_index,
218 _indy_index,
219 pool()->tag_at(_bss_index),
220 CHECK_false);
221 return recorded_res_status;
222 }
223
224 void BootstrapInfo::resolve_newly_linked_invokedynamic(CallInfo& result, TRAPS) {
225 assert(is_resolved(), "");
226 result.set_handle(vmClasses::MethodHandle_klass(), resolved_method(), resolved_appendix(), CHECK);
227 }
228
229 void BootstrapInfo::print_msg_on(outputStream* st, const char* msg) {
230 ResourceMark rm;
231 char what[20];
232 st = st ? st : tty;
233
234 if (_indy_index > -1) {
235 os::snprintf_checked(what, sizeof(what), "indy#%d", _indy_index);
236 } else {
237 os::snprintf_checked(what, sizeof(what), "condy");
238 }
239 bool have_msg = (msg != nullptr && strlen(msg) > 0);
240 st->print_cr("%s%sBootstrap in %s %s@CP[%d] %s:%s%s BSMS[%d] BSM@CP[%d]%s argc=%d%s",
241 (have_msg ? msg : ""), (have_msg ? " " : ""),
242 caller()->name()->as_C_string(),
243 what, // "indy#42" or "condy"
244 _bss_index,
245 _name->as_C_string(),
246 _signature->as_C_string(),
247 (_type_arg.is_null() ? "" : "(resolved)"),
248 bsms_attr_index(),
249 bsm_index(), (_bsm.is_null() ? "" : "(resolved)"),
250 _argc, (_arg_values.is_null() ? "" : "(resolved)"));
251 if (_argc > 0) {
252 char argbuf[80];
253 argbuf[0] = 0;
254 for (int i = 0; i < _argc; i++) {
255 int pos = (int) strlen(argbuf);
256 if (pos + 20 > (int)sizeof(argbuf)) {
257 os::snprintf_checked(argbuf + pos, sizeof(argbuf) - pos, "...");
258 break;
259 }
260 if (i > 0) argbuf[pos++] = ',';
261 os::snprintf_checked(argbuf+pos, sizeof(argbuf) - pos, "%d", arg_index(i));
262 }
263 st->print_cr(" argument indexes: {%s}", argbuf);
264 }
265 if (_bsm.not_null()) {
266 st->print(" resolved BSM: "); _bsm->print_on(st);
267 }
268
269 // How the array of resolved arguments is printed depends highly
270 // on how BootstrapInfo::resolve_args structures the array based on
271 // the use_BSCI setting.
272 if (_arg_values.not_null()) {
273 // Find the static arguments within the first element of _arg_values.
274 oop static_args = _arg_values();
275 if (!static_args->is_array()) {
276 assert(_argc == 1, "Invalid BSM _arg_values for non-array");
277 st->print(" resolved arg[0]: "); static_args->print_on(st);
278 } else if (static_args->is_refArray()) {
279 refArrayOop static_args_array = oop_cast<refArrayOop>(static_args);
280 int lines = 0;
281 for (int i = 0; i < _argc; i++) {
282 oop x = static_args_array->obj_at(i);
283 if (x != nullptr) {
284 if (++lines > 6) {
285 st->print_cr(" resolved arg[%d]: ...", i);
286 break;
287 }
288 st->print(" resolved arg[%d]: ", i); x->print_on(st);
289 }
290 }
291 } else if (static_args->is_typeArray()) {
292 typeArrayOop tmp_array = (typeArrayOop) static_args;
293 assert(tmp_array->length() == 2, "Invalid BSM _arg_values type array");
294 st->print_cr(" resolved arg[0]: %d", tmp_array->int_at(0));
295 st->print_cr(" resolved arg[1]: %d", tmp_array->int_at(1));
296 } else if (static_args->is_flatArray()) {
297 ShouldNotReachHere();
298 }
299 }
300 }