1 /*
2 * Copyright (c) 1997, 2023, 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 "asm/assembler.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "memory/oopFactory.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "memory/universe.hpp"
33 #include "oops/instanceKlass.hpp"
34 #include "oops/klass.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "oops/symbol.hpp"
37 #include "oops/typeArrayKlass.hpp"
38 #include "runtime/fieldDescriptor.inline.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "runtime/safepointVerifiers.hpp"
41 #include "runtime/sharedRuntime.hpp"
42 #include "runtime/signature.hpp"
43 #include "runtime/sharedRuntime.hpp"
44
45 // Implementation of SignatureIterator
46
47 // Signature syntax:
48 //
49 // Signature = "(" {Parameter} ")" ReturnType.
50 // Parameter = FieldType.
51 // ReturnType = FieldType | "V".
52 // FieldType = "B" | "C" | "D" | "F" | "I" | "J" | "S" | "Z" | "L" ClassName ";" | "[" FieldType.
53 // ClassName = string.
54
55 // The ClassName string can be any JVM-style UTF8 string except:
56 // - an empty string (the empty string is never a name of any kind)
57 // - a string which begins or ends with slash '/' (the package separator)
58 // - a string which contains adjacent slashes '//' (no empty package names)
59 // - a string which contains a semicolon ';' (the end-delimiter)
60 // - a string which contains a left bracket '[' (the array marker)
61 // - a string which contains a dot '.' (the external package separator)
62 //
63 // Other "meta-looking" characters, such as '(' and '<' and '+',
64 // are perfectly legitimate within a class name, for the JVM.
65 // Class names which contain double slashes ('a//b') and non-initial
66 // brackets ('a[b]') are reserved for possible enrichment of the
67 // type language.
68
69 void SignatureIterator::set_fingerprint(fingerprint_t fingerprint) {
70 if (!fp_is_valid(fingerprint)) {
71 _fingerprint = fingerprint;
72 _return_type = T_ILLEGAL;
73 } else if (fingerprint != _fingerprint) {
74 assert(_fingerprint == zero_fingerprint(), "consistent fingerprint values");
75 _fingerprint = fingerprint;
76 _return_type = fp_return_type(fingerprint);
77 }
78 }
79
80 BasicType SignatureIterator::return_type() {
81 if (_return_type == T_ILLEGAL) {
82 SignatureStream ss(_signature);
83 ss.skip_to_return_type();
84 _return_type = ss.type();
85 assert(_return_type != T_ILLEGAL, "illegal return type");
86 }
87 return _return_type;
88 }
89
90 bool SignatureIterator::fp_is_valid_type(BasicType type, bool for_return_type) {
91 assert(type != (BasicType)fp_parameters_done, "fingerprint is incorrectly at done");
92 assert(((int)type & ~fp_parameter_feature_mask) == 0, "fingerprint feature mask yielded non-zero value");
93 return (is_java_primitive(type) ||
94 is_reference_type(type) ||
95 (for_return_type && type == T_VOID));
96 }
97
98 ArgumentSizeComputer::ArgumentSizeComputer(Symbol* signature)
99 : SignatureIterator(signature)
100 {
101 _size = 0;
102 do_parameters_on(this); // non-virtual template execution
103 }
104
105 ArgumentCount::ArgumentCount(Symbol* signature)
106 : SignatureIterator(signature)
107 {
108 _size = 0;
109 do_parameters_on(this); // non-virtual template execution
110 }
111
112 ReferenceArgumentCount::ReferenceArgumentCount(Symbol* signature)
113 : SignatureIterator(signature)
114 {
115 _refs = 0;
116 do_parameters_on(this); // non-virtual template execution
117 }
118
119 #if !defined(_LP64) || defined(ZERO) || defined(ASSERT)
120 static int compute_num_stack_arg_slots(Symbol* signature, int sizeargs, bool is_static) {
121 ResourceMark rm;
122 BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sizeargs);
123 VMRegPair* regs = NEW_RESOURCE_ARRAY(VMRegPair, sizeargs);
124
125 int sig_index = 0;
126 if (!is_static) {
127 sig_bt[sig_index++] = T_OBJECT; // 'this'
128 }
129 for (SignatureStream ss(signature); !ss.at_return_type(); ss.next()) {
130 BasicType t = ss.type();
131 assert(type2size[t] == 1 || type2size[t] == 2, "size is 1 or 2");
132 sig_bt[sig_index++] = t;
133 if (type2size[t] == 2) {
134 sig_bt[sig_index++] = T_VOID;
135 }
136 }
137 assert(sig_index == sizeargs, "sig_index: %d sizeargs: %d", sig_index, sizeargs);
138
139 return SharedRuntime::java_calling_convention(sig_bt, regs, sizeargs);
140 }
141 #endif
142
143 void Fingerprinter::compute_fingerprint_and_return_type(bool static_flag) {
144 // See if we fingerprinted this method already
145 if (_method != nullptr) {
146 assert(!static_flag, "must not be passed by caller");
147 static_flag = _method->is_static();
148 _fingerprint = _method->constMethod()->fingerprint();
149
150 if (_fingerprint != zero_fingerprint()) {
151 _return_type = _method->result_type();
152 assert(is_java_type(_return_type), "return type must be a java type");
153 return;
154 }
155
156 if (_method->size_of_parameters() > fp_max_size_of_parameters) {
157 _fingerprint = overflow_fingerprint();
158 _method->constMethod()->set_fingerprint(_fingerprint);
159 // as long as we are here compute the return type:
160 _return_type = ResultTypeFinder(_method->signature()).type();
161 assert(is_java_type(_return_type), "return type must be a java type");
162 return;
163 }
164 }
165
166 // Note: This will always take the slow path, since _fp==zero_fp.
167 initialize_accumulator();
168 initialize_calling_convention(static_flag);
169 do_parameters_on(this);
170 assert(fp_is_valid_type(_return_type, true), "bad result type");
171
172 // Fill in the return type and static bits:
173 _accumulator |= _return_type << fp_static_feature_size;
174 if (static_flag) {
175 _accumulator |= fp_is_static_bit;
176 } else {
177 _param_size += 1; // this is the convention for Method::compute_size_of_parameters
178 }
179
180 #if defined(_LP64) && !defined(ZERO)
181 _stack_arg_slots = align_up(_stack_arg_slots, 2);
182 #ifdef ASSERT
183 int dbg_stack_arg_slots = compute_num_stack_arg_slots(_signature, _param_size, static_flag);
184 assert(_stack_arg_slots == dbg_stack_arg_slots, "fingerprinter: %d full: %d", _stack_arg_slots, dbg_stack_arg_slots);
185 #endif
186 #else
187 // Fallback: computed _stack_arg_slots is unreliable, compute directly.
188 _stack_arg_slots = compute_num_stack_arg_slots(_signature, _param_size, static_flag);
189 #endif
190
191 // Detect overflow. (We counted _param_size correctly.)
192 if (_method == nullptr && _param_size > fp_max_size_of_parameters) {
193 // We did a one-pass computation of argument size, return type,
194 // and fingerprint.
195 _fingerprint = overflow_fingerprint();
196 return;
197 }
198
199 assert(_shift_count < BitsPerLong,
200 "shift count overflow %d (%d vs. %d): %s",
201 _shift_count, _param_size, fp_max_size_of_parameters,
202 _signature->as_C_string());
203 assert((_accumulator >> _shift_count) == fp_parameters_done, "must be zero");
204
205 // This is the result, along with _return_type:
206 _fingerprint = _accumulator;
207
208 // Cache the result on the method itself:
209 if (_method != nullptr) {
210 _method->constMethod()->set_fingerprint(_fingerprint);
211 }
212 }
213
214 void Fingerprinter::initialize_calling_convention(bool static_flag) {
215 _int_args = 0;
216 _fp_args = 0;
217
218 if (!static_flag) { // `this` takes up an int register
219 _int_args++;
220 }
221 }
222
223 void Fingerprinter::do_type_calling_convention(BasicType type) {
224 // We compute the number of slots for stack-passed arguments in compiled calls.
225 // TODO: SharedRuntime::java_calling_convention is the shared code that knows all details
226 // about the platform-specific calling conventions. This method tries to compute the stack
227 // args number... poorly, at least for 32-bit ports and for zero. Current code has the fallback
228 // that recomputes the stack args number from SharedRuntime::java_calling_convention.
229 #if defined(_LP64) && !defined(ZERO)
230 switch (type) {
231 case T_VOID:
232 break;
233 case T_BOOLEAN:
234 case T_CHAR:
235 case T_BYTE:
236 case T_SHORT:
237 case T_INT:
238 #if defined(PPC64) || defined(S390)
239 if (_int_args < Argument::n_int_register_parameters_j) {
240 _int_args++;
241 } else {
242 _stack_arg_slots += 1;
243 }
244 break;
245 #endif // defined(PPC64) || defined(S390)
246 case T_LONG:
247 case T_OBJECT:
248 case T_ARRAY:
249 case T_ADDRESS:
250 if (_int_args < Argument::n_int_register_parameters_j) {
251 _int_args++;
252 } else {
253 PPC64_ONLY(_stack_arg_slots = align_up(_stack_arg_slots, 2));
254 S390_ONLY(_stack_arg_slots = align_up(_stack_arg_slots, 2));
255 _stack_arg_slots += 2;
256 }
257 break;
258 case T_FLOAT:
259 #if defined(PPC64) || defined(S390)
260 if (_fp_args < Argument::n_float_register_parameters_j) {
261 _fp_args++;
262 } else {
263 _stack_arg_slots += 1;
264 }
265 break;
266 #endif // defined(PPC64) || defined(S390)
267 case T_DOUBLE:
268 if (_fp_args < Argument::n_float_register_parameters_j) {
269 _fp_args++;
270 } else {
271 PPC64_ONLY(_stack_arg_slots = align_up(_stack_arg_slots, 2));
272 S390_ONLY(_stack_arg_slots = align_up(_stack_arg_slots, 2));
273 _stack_arg_slots += 2;
274 }
275 break;
276 default:
277 ShouldNotReachHere();
278 break;
279 }
280 #endif
281 }
282
283 // Implementation of SignatureStream
284
285 static inline BasicType decode_signature_char(int ch) {
286 switch (ch) {
287 #define EACH_SIG(ch, bt, ignore) \
288 case ch: return bt;
289 SIGNATURE_TYPES_DO(EACH_SIG, ignore)
290 #undef EACH_SIG
291 }
292 return (BasicType)0;
293 }
294
295 SignatureStream::SignatureStream(const Symbol* signature,
296 bool is_method) {
297 assert(!is_method || signature->starts_with(JVM_SIGNATURE_FUNC),
298 "method signature required");
299 _signature = signature;
300 _limit = signature->utf8_length();
301 int oz = (is_method ? _s_method : _s_field);
302 _state = oz;
303 _begin = _end = oz; // skip first '(' in method signatures
304 _array_prefix = 0; // just for definiteness
305
306 // assigning java/lang/Object to _previous_name means we can
307 // avoid a number of null checks in the parser
308 _previous_name = vmSymbols::java_lang_Object();
309 _names = nullptr;
310 next();
311 }
312
313 SignatureStream::~SignatureStream() {
314 if (_previous_name == vmSymbols::java_lang_Object()) {
315 // no names were created
316 assert(_names == nullptr, "_names unexpectedly created");
317 return;
318 }
319
320 // decrement refcount for names created during signature parsing
321 _previous_name->decrement_refcount();
322 if (_names != nullptr) {
323 for (int i = 0; i < _names->length(); i++) {
324 _names->at(i)->decrement_refcount();
325 }
326 }
327 }
328
329 inline int SignatureStream::scan_type(BasicType type) {
330 const u1* base = _signature->bytes();
331 int end = _end;
332 int limit = _limit;
333 const u1* tem;
334 switch (type) {
335 case T_OBJECT:
336 tem = (const u1*) memchr(&base[end], JVM_SIGNATURE_ENDCLASS, limit - end);
337 return (tem == nullptr ? limit : pointer_delta_as_int(tem + 1, base));
338
339 case T_ARRAY:
340 while ((end < limit) && ((char)base[end] == JVM_SIGNATURE_ARRAY)) { end++; }
341 // If we discovered only the string of '[', this means something is wrong.
342 if (end >= limit) {
343 assert(false, "Invalid type detected");
344 return limit;
345 }
346 _array_prefix = end - _end; // number of '[' chars just skipped
347 if (Signature::has_envelope(base[end])) {
348 tem = (const u1 *) memchr(&base[end], JVM_SIGNATURE_ENDCLASS, limit - end);
349 return (tem == nullptr ? limit : pointer_delta_as_int(tem + 1, base));
350 }
351 // Skipping over a single character for a primitive type.
352 assert(is_java_primitive(decode_signature_char(base[end])), "only primitives expected");
353 return end + 1;
354
355 default:
356 // Skipping over a single character for a primitive type (or void).
357 assert(!is_reference_type(type), "only primitives or void expected");
358 return end + 1;
359 }
360 }
361
362 void SignatureStream::next() {
363 const Symbol* sig = _signature;
364 int len = _limit;
365 if (_end >= len) { set_done(); return; }
366 _begin = _end;
367 int ch = sig->char_at(_begin);
368 if (ch == JVM_SIGNATURE_ENDFUNC) {
369 assert(_state == _s_method, "must be in method");
370 _state = _s_method_return;
371 _begin = ++_end;
372 if (_end >= len) { set_done(); return; }
373 ch = sig->char_at(_begin);
374 }
375 BasicType bt = decode_signature_char(ch);
376 assert(ch == type2char(bt), "bad signature char %c/%d", ch, ch);
377 _type = bt;
378 _end = scan_type(bt);
379 }
380
381 int SignatureStream::skip_whole_array_prefix() {
382 assert(_type == T_ARRAY, "must be");
383
384 // we are stripping all levels of T_ARRAY,
385 // so we must decode the next character
386 int whole_array_prefix = _array_prefix;
387 int new_begin = _begin + whole_array_prefix;
388 _begin = new_begin;
389 int ch = _signature->char_at(new_begin);
390 BasicType bt = decode_signature_char(ch);
391 assert(ch == type2char(bt), "bad signature char %c/%d", ch, ch);
392 _type = bt;
393 assert(bt != T_VOID && bt != T_ARRAY, "bad signature type");
394 // Don't bother to re-scan, since it won't change the value of _end.
395 return whole_array_prefix;
396 }
397
398 bool Signature::is_valid_array_signature(const Symbol* sig) {
399 assert(sig->utf8_length() > 1, "this should already have been checked");
400 assert(sig->char_at(0) == JVM_SIGNATURE_ARRAY, "this should already have been checked");
401 // The first character is already checked
402 int i = 1;
403 int len = sig->utf8_length();
404 // First skip all '['s
405 while(i < len - 1 && sig->char_at(i) == JVM_SIGNATURE_ARRAY) i++;
406
407 // Check type
408 switch(sig->char_at(i)) {
409 case JVM_SIGNATURE_BYTE:
410 case JVM_SIGNATURE_CHAR:
411 case JVM_SIGNATURE_DOUBLE:
412 case JVM_SIGNATURE_FLOAT:
413 case JVM_SIGNATURE_INT:
414 case JVM_SIGNATURE_LONG:
415 case JVM_SIGNATURE_SHORT:
416 case JVM_SIGNATURE_BOOLEAN:
417 // If it is an array, the type is the last character
418 return (i + 1 == len);
419 case JVM_SIGNATURE_CLASS:
420 // If it is an object, the last character must be a ';'
421 return sig->char_at(len - 1) == JVM_SIGNATURE_ENDCLASS;
422 }
423 return false;
424 }
425
426 BasicType Signature::basic_type(int ch) {
427 BasicType btcode = decode_signature_char(ch);
428 if (btcode == 0) return T_ILLEGAL;
429 return btcode;
430 }
431
432 Symbol* Signature::strip_envelope(const Symbol* signature) {
433 assert(has_envelope(signature), "precondition");
434 return SymbolTable::new_symbol((char*) signature->bytes() + 1,
435 signature->utf8_length() - 2);
436 }
437
438 static const int jl_len = 10, object_len = 6, jl_object_len = jl_len + object_len;
439 static const char jl_str[] = "java/lang/";
440
441 #ifdef ASSERT
442 static bool signature_symbols_sane() {
443 static bool done;
444 if (done) return true;
445 done = true;
446 // test some tense code that looks for common symbol names:
447 assert(vmSymbols::java_lang_Object()->utf8_length() == jl_object_len &&
448 vmSymbols::java_lang_Object()->starts_with(jl_str, jl_len) &&
449 vmSymbols::java_lang_Object()->ends_with("Object", object_len) &&
450 vmSymbols::java_lang_Object()->is_permanent() &&
451 vmSymbols::java_lang_String()->utf8_length() == jl_object_len &&
452 vmSymbols::java_lang_String()->starts_with(jl_str, jl_len) &&
453 vmSymbols::java_lang_String()->ends_with("String", object_len) &&
454 vmSymbols::java_lang_String()->is_permanent(),
455 "sanity");
456 return true;
457 }
458 #endif //ASSERT
459
460 // returns a symbol; the caller is responsible for decrementing it
461 Symbol* SignatureStream::find_symbol() {
462 // Create a symbol from for string _begin _end
463 int begin = raw_symbol_begin();
464 int end = raw_symbol_end();
465
466 const char* symbol_chars = (const char*)_signature->base() + begin;
467 int len = end - begin;
468
469 // Quick check for common symbols in signatures
470 assert(signature_symbols_sane(), "incorrect signature sanity check");
471 if (len == jl_object_len &&
472 memcmp(symbol_chars, jl_str, jl_len) == 0) {
473 if (memcmp("String", symbol_chars + jl_len, object_len) == 0) {
474 return vmSymbols::java_lang_String();
475 } else if (memcmp("Object", symbol_chars + jl_len, object_len) == 0) {
476 return vmSymbols::java_lang_Object();
477 }
478 }
479
480 Symbol* name = _previous_name;
481 if (name->equals(symbol_chars, len)) {
482 return name;
483 }
484
485 // Save names for cleaning up reference count at the end of
486 // SignatureStream scope.
487 name = SymbolTable::new_symbol(symbol_chars, len);
488
489 // Only allocate the GrowableArray for the _names buffer if more than
490 // one name is being processed in the signature.
491 if (!_previous_name->is_permanent()) {
492 if (_names == nullptr) {
493 _names = new GrowableArray<Symbol*>(10);
494 }
495 _names->push(_previous_name);
496 }
497 _previous_name = name;
498 return name;
499 }
500
501 Klass* SignatureStream::as_klass(Handle class_loader, Handle protection_domain,
502 FailureMode failure_mode, TRAPS) {
503 if (!is_reference()) {
504 return nullptr;
505 }
506 Symbol* name = as_symbol();
507 Klass* k = nullptr;
508 if (failure_mode == ReturnNull) {
509 // Note: SD::resolve_or_null returns null for most failure modes,
510 // but not all. Circularity errors, invalid PDs, etc., throw.
511 k = SystemDictionary::resolve_or_null(name, class_loader, protection_domain, CHECK_NULL);
512 } else if (failure_mode == CachedOrNull) {
513 NoSafepointVerifier nsv; // no loading, now, we mean it!
514 assert(!HAS_PENDING_EXCEPTION, "");
515 k = SystemDictionary::find_instance_klass(THREAD, name, class_loader, protection_domain);
516 // SD::find does not trigger loading, so there should be no throws
517 // Still, bad things can happen, so we CHECK_NULL and ask callers
518 // to do likewise.
519 return k;
520 } else {
521 // The only remaining failure mode is NCDFError.
522 // The test here allows for an additional mode CNFException
523 // if callers need to request the reflective error instead.
524 bool throw_error = (failure_mode == NCDFError);
525 k = SystemDictionary::resolve_or_fail(name, class_loader, protection_domain, throw_error, CHECK_NULL);
526 }
527
528 return k;
529 }
530
531 oop SignatureStream::as_java_mirror(Handle class_loader, Handle protection_domain,
532 FailureMode failure_mode, TRAPS) {
533 if (!is_reference()) {
534 return Universe::java_mirror(type());
535 }
536 Klass* klass = as_klass(class_loader, protection_domain, failure_mode, CHECK_NULL);
537 if (klass == nullptr) {
538 return nullptr;
539 }
540 return klass->java_mirror();
541 }
542
543 void SignatureStream::skip_to_return_type() {
544 while (!at_return_type()) {
545 next();
546 }
547 }
548
549 ResolvingSignatureStream::ResolvingSignatureStream(Symbol* signature,
550 Handle class_loader,
551 Handle protection_domain,
552 bool is_method)
553 : SignatureStream(signature, is_method),
554 _class_loader(class_loader), _protection_domain(protection_domain)
555 {
556 initialize_load_origin(nullptr);
557 }
558
559 ResolvingSignatureStream::ResolvingSignatureStream(Symbol* signature, Klass* load_origin, bool is_method)
560 : SignatureStream(signature, is_method)
561 {
562 assert(load_origin != nullptr, "");
563 initialize_load_origin(load_origin);
564 }
565
566 ResolvingSignatureStream::ResolvingSignatureStream(const Method* method)
567 : SignatureStream(method->signature(), true)
568 {
569 initialize_load_origin(method->method_holder());
570 }
571
572 void ResolvingSignatureStream::cache_handles() {
573 assert(_load_origin != nullptr, "");
574 JavaThread* current = JavaThread::current();
575 _class_loader = Handle(current, _load_origin->class_loader());
576 _protection_domain = Handle(current, _load_origin->protection_domain());
577 }
578
579 #ifdef ASSERT
580
581 extern bool signature_constants_sane(); // called from basic_types_init()
582
583 bool signature_constants_sane() {
584 // for the lookup table, test every 8-bit code point, and then some:
585 for (int i = -256; i <= 256; i++) {
586 int btcode = 0;
587 switch (i) {
588 #define EACH_SIG(ch, bt, ignore) \
589 case ch: { btcode = bt; break; }
590 SIGNATURE_TYPES_DO(EACH_SIG, ignore)
591 #undef EACH_SIG
592 }
593 int btc = decode_signature_char(i);
594 assert(btc == btcode, "misconfigured table: %d => %d not %d", i, btc, btcode);
595 }
596 return true;
597 }
598
599 bool SignatureVerifier::is_valid_method_signature(Symbol* sig) {
600 const char* method_sig = (const char*)sig->bytes();
601 ssize_t len = sig->utf8_length();
602 ssize_t index = 0;
603 if (method_sig != nullptr && len > 1 && method_sig[index] == JVM_SIGNATURE_FUNC) {
604 ++index;
605 while (index < len && method_sig[index] != JVM_SIGNATURE_ENDFUNC) {
606 ssize_t res = is_valid_type(&method_sig[index], len - index);
607 if (res == -1) {
608 return false;
609 } else {
610 index += res;
611 }
612 }
613 if (index < len && method_sig[index] == JVM_SIGNATURE_ENDFUNC) {
614 // check the return type
615 ++index;
616 return (is_valid_type(&method_sig[index], len - index) == (len - index));
617 }
618 }
619 return false;
620 }
621
622 bool SignatureVerifier::is_valid_type_signature(Symbol* sig) {
623 const char* type_sig = (const char*)sig->bytes();
624 ssize_t len = sig->utf8_length();
625 return (type_sig != nullptr && len >= 1 &&
626 (is_valid_type(type_sig, len) == len));
627 }
628
629 // Checks to see if the type (not to go beyond 'limit') refers to a valid type.
630 // Returns -1 if it is not, or the index of the next character that is not part
631 // of the type. The type encoding may end before 'limit' and that's ok.
632 ssize_t SignatureVerifier::is_valid_type(const char* type, ssize_t limit) {
633 ssize_t index = 0;
634
635 // Iterate over any number of array dimensions
636 while (index < limit && type[index] == JVM_SIGNATURE_ARRAY) ++index;
637 if (index >= limit) {
638 return -1;
639 }
640 switch (type[index]) {
641 case JVM_SIGNATURE_BYTE:
642 case JVM_SIGNATURE_CHAR:
643 case JVM_SIGNATURE_FLOAT:
644 case JVM_SIGNATURE_DOUBLE:
645 case JVM_SIGNATURE_INT:
646 case JVM_SIGNATURE_LONG:
647 case JVM_SIGNATURE_SHORT:
648 case JVM_SIGNATURE_BOOLEAN:
649 case JVM_SIGNATURE_VOID:
650 return index + 1;
651 case JVM_SIGNATURE_CLASS:
652 for (index = index + 1; index < limit; ++index) {
653 char c = type[index];
654 switch (c) {
655 case JVM_SIGNATURE_ENDCLASS:
656 return index + 1;
657 case '\0': case JVM_SIGNATURE_DOT: case JVM_SIGNATURE_ARRAY:
658 return -1;
659 default: ; // fall through
660 }
661 }
662 // fall through
663 default: ; // fall through
664 }
665 return -1;
666 }
667
668 #endif // ASSERT