1 /*
2 * Copyright (c) 2019, 2025, 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
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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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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/resolvedIndyEntry.hpp"
40 #include "oops/typeArrayOop.inline.hpp"
41 #include "runtime/handles.inline.hpp"
42 #include "runtime/javaThread.hpp"
43 #include "runtime/vmThread.hpp"
44
45 //------------------------------------------------------------------------------------------------------------------------
46 // Implementation of BootstrapInfo
47
48 BootstrapInfo::BootstrapInfo(const constantPoolHandle& pool, int bss_index, int indy_index)
49 : _pool(pool),
50 _bss_index(bss_index),
51 _indy_index(indy_index),
52 // derived and eagerly cached:
53 _argc( pool->bootstrap_argument_count_at(bss_index) ),
54 _name( pool->uncached_name_ref_at(bss_index) ),
55 _signature( pool->uncached_signature_ref_at(bss_index) )
56 {
57 _is_resolved = false;
58 assert(pool->tag_at(bss_index).has_bootstrap(), "");
59 assert(indy_index == -1 || pool->resolved_indy_entry_at(indy_index)->constant_pool_index() == bss_index, "invalid bootstrap specifier index");
60 }
61
62 // If there is evidence this call site was already linked, set the
63 // existing linkage data into result, or throw previous exception.
64 // Return true if either action is taken, else false.
65 bool BootstrapInfo::resolve_previously_linked_invokedynamic(CallInfo& result, TRAPS) {
66 assert(_indy_index != -1, "");
67 // Check if method is not null
68 ResolvedIndyEntry* indy_entry = _pool->resolved_indy_entry_at(_indy_index);
69 if (indy_entry->method() != nullptr) {
70 methodHandle method(THREAD, indy_entry->method());
71 Handle appendix(THREAD, _pool->resolved_reference_from_indy(_indy_index));
72 result.set_handle(vmClasses::MethodHandle_klass(), method, appendix, THREAD);
73 Exceptions::wrap_dynamic_exception(/* is_indy */ true, CHECK_false);
74 return true;
75 } else if (indy_entry->resolution_failed()) {
76 int encoded_index = ResolutionErrorTable::encode_indy_index(_indy_index);
77 ConstantPool::throw_resolution_error(_pool, encoded_index, CHECK_false); // Doesn't necessarily need to be resolved yet
78 return true;
79 } else {
80 return false;
81 }
82 }
83
84 // Resolve the bootstrap specifier in 3 steps:
85 // - unpack the BSM by resolving the MH constant
86 // - obtain the NameAndType description for the condy/indy
87 // - prepare the BSM's static arguments
88 Handle BootstrapInfo::resolve_bsm(TRAPS) {
89 if (_bsm.not_null()) {
90 return _bsm;
91 }
92
93 bool is_indy = is_method_call();
94 // The tag at the bootstrap method index must be a valid method handle or a method handle in error.
95 // If it is a MethodHandleInError, a resolution error will be thrown which will be wrapped if necessary
96 // with a BootstrapMethodError.
97 assert(_pool->tag_at(bsm_index()).is_method_handle() ||
98 _pool->tag_at(bsm_index()).is_method_handle_in_error(), "MH not present, classfile structural constraint");
99 oop bsm_oop = _pool->resolve_possibly_cached_constant_at(bsm_index(), THREAD);
100 Exceptions::wrap_dynamic_exception(is_indy, CHECK_NH);
101 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm_oop), "classfile must supply a valid BSM");
102 _bsm = Handle(THREAD, bsm_oop);
103
104 // Obtain NameAndType information
105 resolve_bss_name_and_type(THREAD);
106 Exceptions::wrap_dynamic_exception(is_indy, CHECK_NH);
107
108 // Prepare static arguments
109 resolve_args(THREAD);
110 Exceptions::wrap_dynamic_exception(is_indy, CHECK_NH);
111
112 return _bsm;
113 }
114
115 // Resolve metadata from the JVM_Dynamic_info or JVM_InvokeDynamic_info's name and type information.
116 void BootstrapInfo::resolve_bss_name_and_type(TRAPS) {
117 assert(_bsm.not_null(), "resolve_bsm first");
118 Symbol* name = this->name();
119 Symbol* type = this->signature();
120 _name_arg = java_lang_String::create_from_symbol(name, CHECK);
121 if (type->char_at(0) == '(') {
122 _type_arg = SystemDictionary::find_method_handle_type(type, caller(), CHECK);
123 } else {
124 _type_arg = SystemDictionary::find_java_mirror_for_type(type, caller(), SignatureStream::NCDFError, CHECK);
125 }
126 }
127
128 // Resolve the bootstrap method's static arguments and store the result in _arg_values.
129 void BootstrapInfo::resolve_args(TRAPS) {
130 assert(_bsm.not_null(), "resolve_bsm first");
131
132 // if there are no static arguments, return leaving _arg_values as null
133 if (_argc == 0 && UseBootstrapCallInfo < 2) return;
134
135 bool use_BSCI;
136 switch (UseBootstrapCallInfo) {
137 default: use_BSCI = true; break; // stress mode
138 case 0: use_BSCI = false; break; // stress mode
139 case 1: // normal mode
140 // If we were to support an alternative mode of BSM invocation,
141 // we'd convert to pull mode here if the BSM could be a candidate
142 // for that alternative mode. We can't easily test for things
143 // like varargs here, but we can get away with approximate testing,
144 // since the JDK runtime will make up the difference either way.
145 // For now, exercise the pull-mode path if the BSM is of arity 2,
146 // or if there is a potential condy loop (see below).
147 oop mt_oop = java_lang_invoke_MethodHandle::type(_bsm());
148 use_BSCI = (java_lang_invoke_MethodType::ptype_count(mt_oop) == 2);
149 break;
150 }
151
152 // Here's a reason to use BSCI even if it wasn't requested:
153 // If a condy uses a condy argument, we want to avoid infinite
154 // recursion (condy loops) in the C code. It's OK in Java,
155 // because Java has stack overflow checking, so we punt
156 // potentially cyclic cases from C to Java.
157 if (!use_BSCI && _pool->tag_at(_bss_index).is_dynamic_constant()) {
158 bool found_unresolved_condy = false;
159 for (int i = 0; i < _argc; i++) {
160 int arg_index = _pool->bootstrap_argument_index_at(_bss_index, i);
161 if (_pool->tag_at(arg_index).is_dynamic_constant()) {
162 // potential recursion point condy -> condy
163 bool found_it = false;
164 _pool->find_cached_constant_at(arg_index, found_it, CHECK);
165 if (!found_it) { found_unresolved_condy = true; break; }
166 }
167 }
168 if (found_unresolved_condy)
169 use_BSCI = true;
170 }
171
172 const int SMALL_ARITY = 5;
173 if (use_BSCI && _argc <= SMALL_ARITY && UseBootstrapCallInfo <= 2) {
174 // If there are only a few arguments, and none of them need linking,
175 // push them, instead of asking the JDK runtime to turn around and
176 // pull them, saving a JVM/JDK transition in some simple cases.
177 bool all_resolved = true;
178 for (int i = 0; i < _argc; i++) {
179 bool found_it = false;
180 int arg_index = _pool->bootstrap_argument_index_at(_bss_index, i);
181 _pool->find_cached_constant_at(arg_index, found_it, CHECK);
182 if (!found_it) { all_resolved = false; break; }
183 }
184 if (all_resolved)
185 use_BSCI = false;
186 }
187
188 if (!use_BSCI) {
189 // return {arg...}; resolution of arguments is done immediately, before JDK code is called
190 objArrayOop args_oop = oopFactory::new_objArray(vmClasses::Object_klass(), _argc, CHECK);
191 objArrayHandle args(THREAD, args_oop);
192 _pool->copy_bootstrap_arguments_at(_bss_index, 0, _argc, args, 0, true, Handle(), CHECK);
193 oop arg_oop = ((_argc == 1) ? args->obj_at(0) : (oop)nullptr);
194 // try to discard the singleton array
195 if (arg_oop != nullptr && !arg_oop->is_array()) {
196 // JVM treats arrays and nulls specially in this position,
197 // but other things are just single arguments
198 _arg_values = Handle(THREAD, arg_oop);
199 } else {
200 _arg_values = args;
201 }
202 } else {
203 // return {arg_count, pool_index}; JDK code must pull the arguments as needed
204 typeArrayOop ints_oop = oopFactory::new_typeArray(T_INT, 2, CHECK);
205 ints_oop->int_at_put(0, _argc);
206 ints_oop->int_at_put(1, _bss_index);
207 _arg_values = Handle(THREAD, ints_oop);
208 }
209 }
210
211 // there must be a LinkageError pending; try to save it and then throw
212 bool BootstrapInfo::save_and_throw_indy_exc(TRAPS) {
213 assert(HAS_PENDING_EXCEPTION, "");
214 assert(_indy_index != -1, "");
215 assert(_indy_index >= 0, "Indy index must be decoded by now");
216 bool recorded_res_status = _pool->cache()->save_and_throw_indy_exc(_pool, _bss_index,
217 _indy_index,
218 pool()->tag_at(_bss_index),
219 CHECK_false);
220 return recorded_res_status;
221 }
222
223 void BootstrapInfo::resolve_newly_linked_invokedynamic(CallInfo& result, TRAPS) {
224 assert(is_resolved(), "");
225 result.set_handle(vmClasses::MethodHandle_klass(), resolved_method(), resolved_appendix(), CHECK);
226 }
227
228 void BootstrapInfo::print_msg_on(outputStream* st, const char* msg) {
229 ResourceMark rm;
230 char what[20];
231 st = st ? st : tty;
232
233 if (_indy_index > -1) {
234 os::snprintf_checked(what, sizeof(what), "indy#%d", _indy_index);
235 } else {
236 os::snprintf_checked(what, sizeof(what), "condy");
237 }
238 bool have_msg = (msg != nullptr && strlen(msg) > 0);
239 st->print_cr("%s%sBootstrap in %s %s@CP[%d] %s:%s%s BSMS[%d] BSM@CP[%d]%s argc=%d%s",
240 (have_msg ? msg : ""), (have_msg ? " " : ""),
241 caller()->name()->as_C_string(),
242 what, // "indy#42" or "condy"
243 _bss_index,
244 _name->as_C_string(),
245 _signature->as_C_string(),
246 (_type_arg.is_null() ? "" : "(resolved)"),
247 bsms_attr_index(),
248 bsm_index(), (_bsm.is_null() ? "" : "(resolved)"),
249 _argc, (_arg_values.is_null() ? "" : "(resolved)"));
250 if (_argc > 0) {
251 char argbuf[80];
252 argbuf[0] = 0;
253 for (int i = 0; i < _argc; i++) {
254 int pos = (int) strlen(argbuf);
255 if (pos + 20 > (int)sizeof(argbuf)) {
256 os::snprintf_checked(argbuf + pos, sizeof(argbuf) - pos, "...");
257 break;
258 }
259 if (i > 0) argbuf[pos++] = ',';
260 os::snprintf_checked(argbuf+pos, sizeof(argbuf) - pos, "%d", arg_index(i));
261 }
262 st->print_cr(" argument indexes: {%s}", argbuf);
263 }
264 if (_bsm.not_null()) {
265 st->print(" resolved BSM: "); _bsm->print_on(st);
266 }
267
268 // How the array of resolved arguments is printed depends highly
269 // on how BootstrapInfo::resolve_args structures the array based on
270 // the use_BSCI setting.
271 if (_arg_values.not_null()) {
272 // Find the static arguments within the first element of _arg_values.
273 objArrayOop static_args = (objArrayOop)_arg_values();
274 if (!static_args->is_array()) {
275 assert(_argc == 1, "Invalid BSM _arg_values for non-array");
276 st->print(" resolved arg[0]: "); static_args->print_on(st);
277 } else if (static_args->is_objArray()) {
278 int lines = 0;
279 for (int i = 0; i < _argc; i++) {
280 oop x = static_args->obj_at(i);
281 if (x != nullptr) {
282 if (++lines > 6) {
283 st->print_cr(" resolved arg[%d]: ...", i);
284 break;
285 }
286 st->print(" resolved arg[%d]: ", i); x->print_on(st);
287 }
288 }
289 } else if (static_args->is_typeArray()) {
290 typeArrayOop tmp_array = (typeArrayOop) static_args;
291 assert(tmp_array->length() == 2, "Invalid BSM _arg_values type array");
292 st->print_cr(" resolved arg[0]: %d", tmp_array->int_at(0));
293 st->print_cr(" resolved arg[1]: %d", tmp_array->int_at(1));
294 }
295 }
296 }