verificationType.hpp revision 7421:55e38e5032af
1/* 2 * Copyright (c) 2003, 2014, 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#ifndef SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP 26#define SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP 27 28#include "classfile/systemDictionary.hpp" 29#include "memory/allocation.hpp" 30#include "oops/instanceKlass.hpp" 31#include "oops/oop.inline.hpp" 32#include "oops/symbol.hpp" 33#include "runtime/handles.hpp" 34#include "runtime/signature.hpp" 35 36enum { 37 // As specifed in the JVM spec 38 ITEM_Top = 0, 39 ITEM_Integer = 1, 40 ITEM_Float = 2, 41 ITEM_Double = 3, 42 ITEM_Long = 4, 43 ITEM_Null = 5, 44 ITEM_UninitializedThis = 6, 45 ITEM_Object = 7, 46 ITEM_Uninitialized = 8, 47 ITEM_Bogus = (uint)-1 48}; 49 50class ClassVerifier; 51 52class VerificationType VALUE_OBJ_CLASS_SPEC { 53 private: 54 // Least significant bits of _handle are always 0, so we use these as 55 // the indicator that the _handle is valid. Otherwise, the _data field 56 // contains encoded data (as specified below). Should the VM change 57 // and the lower bits on oops aren't 0, the assert in the constructor 58 // will catch this and we'll have to add a descriminator tag to this 59 // structure. 60 union { 61 Symbol* _sym; 62 uintptr_t _data; 63 } _u; 64 65 enum { 66 // These rest are not found in classfiles, but used by the verifier 67 ITEM_Boolean = 9, ITEM_Byte, ITEM_Short, ITEM_Char, 68 ITEM_Long_2nd, ITEM_Double_2nd 69 }; 70 71 // Enum for the _data field 72 enum { 73 // Bottom two bits determine if the type is a reference, primitive, 74 // uninitialized or a query-type. 75 TypeMask = 0x00000003, 76 77 // Topmost types encoding 78 Reference = 0x0, // _sym contains the name 79 Primitive = 0x1, // see below for primitive list 80 Uninitialized = 0x2, // 0x00ffff00 contains bci 81 TypeQuery = 0x3, // Meta-types used for category testing 82 83 // Utility flags 84 ReferenceFlag = 0x00, // For reference query types 85 Category1Flag = 0x01, // One-word values 86 Category2Flag = 0x02, // First word of a two-word value 87 Category2_2ndFlag = 0x04, // Second word of a two-word value 88 89 // special reference values 90 Null = 0x00000000, // A reference with a 0 sym is null 91 92 // Primitives categories (the second byte determines the category) 93 Category1 = (Category1Flag << 1 * BitsPerByte) | Primitive, 94 Category2 = (Category2Flag << 1 * BitsPerByte) | Primitive, 95 Category2_2nd = (Category2_2ndFlag << 1 * BitsPerByte) | Primitive, 96 97 // Primitive values (type descriminator stored in most-signifcant bytes) 98 Bogus = (ITEM_Bogus << 2 * BitsPerByte) | Category1, 99 Boolean = (ITEM_Boolean << 2 * BitsPerByte) | Category1, 100 Byte = (ITEM_Byte << 2 * BitsPerByte) | Category1, 101 Short = (ITEM_Short << 2 * BitsPerByte) | Category1, 102 Char = (ITEM_Char << 2 * BitsPerByte) | Category1, 103 Integer = (ITEM_Integer << 2 * BitsPerByte) | Category1, 104 Float = (ITEM_Float << 2 * BitsPerByte) | Category1, 105 Long = (ITEM_Long << 2 * BitsPerByte) | Category2, 106 Double = (ITEM_Double << 2 * BitsPerByte) | Category2, 107 Long_2nd = (ITEM_Long_2nd << 2 * BitsPerByte) | Category2_2nd, 108 Double_2nd = (ITEM_Double_2nd << 2 * BitsPerByte) | Category2_2nd, 109 110 // Used by Uninitialized (second and third bytes hold the bci) 111 BciMask = 0xffff << 1 * BitsPerByte, 112 BciForThis = ((u2)-1), // A bci of -1 is an Unintialized-This 113 114 // Query values 115 ReferenceQuery = (ReferenceFlag << 1 * BitsPerByte) | TypeQuery, 116 Category1Query = (Category1Flag << 1 * BitsPerByte) | TypeQuery, 117 Category2Query = (Category2Flag << 1 * BitsPerByte) | TypeQuery, 118 Category2_2ndQuery = (Category2_2ndFlag << 1 * BitsPerByte) | TypeQuery 119 }; 120 121 VerificationType(uintptr_t raw_data) { 122 _u._data = raw_data; 123 } 124 125 public: 126 127 VerificationType() { *this = bogus_type(); } 128 129 // Create verification types 130 static VerificationType bogus_type() { return VerificationType(Bogus); } 131 static VerificationType top_type() { return bogus_type(); } // alias 132 static VerificationType null_type() { return VerificationType(Null); } 133 static VerificationType integer_type() { return VerificationType(Integer); } 134 static VerificationType float_type() { return VerificationType(Float); } 135 static VerificationType long_type() { return VerificationType(Long); } 136 static VerificationType long2_type() { return VerificationType(Long_2nd); } 137 static VerificationType double_type() { return VerificationType(Double); } 138 static VerificationType boolean_type() { return VerificationType(Boolean); } 139 static VerificationType byte_type() { return VerificationType(Byte); } 140 static VerificationType char_type() { return VerificationType(Char); } 141 static VerificationType short_type() { return VerificationType(Short); } 142 static VerificationType double2_type() 143 { return VerificationType(Double_2nd); } 144 145 // "check" types are used for queries. A "check" type is not assignable 146 // to anything, but the specified types are assignable to a "check". For 147 // example, any category1 primitive is assignable to category1_check and 148 // any reference is assignable to reference_check. 149 static VerificationType reference_check() 150 { return VerificationType(ReferenceQuery); } 151 static VerificationType category1_check() 152 { return VerificationType(Category1Query); } 153 static VerificationType category2_check() 154 { return VerificationType(Category2Query); } 155 static VerificationType category2_2nd_check() 156 { return VerificationType(Category2_2ndQuery); } 157 158 // For reference types, store the actual Symbol 159 static VerificationType reference_type(Symbol* sh) { 160 assert(((uintptr_t)sh & 0x3) == 0, "Symbols must be aligned"); 161 // If the above assert fails in the future because oop* isn't aligned, 162 // then this type encoding system will have to change to have a tag value 163 // to descriminate between oops and primitives. 164 return VerificationType((uintptr_t)sh); 165 } 166 static VerificationType uninitialized_type(u2 bci) 167 { return VerificationType(bci << 1 * BitsPerByte | Uninitialized); } 168 static VerificationType uninitialized_this_type() 169 { return uninitialized_type(BciForThis); } 170 171 // Create based on u1 read from classfile 172 static VerificationType from_tag(u1 tag); 173 174 bool is_bogus() const { return (_u._data == Bogus); } 175 bool is_null() const { return (_u._data == Null); } 176 bool is_boolean() const { return (_u._data == Boolean); } 177 bool is_byte() const { return (_u._data == Byte); } 178 bool is_char() const { return (_u._data == Char); } 179 bool is_short() const { return (_u._data == Short); } 180 bool is_integer() const { return (_u._data == Integer); } 181 bool is_long() const { return (_u._data == Long); } 182 bool is_float() const { return (_u._data == Float); } 183 bool is_double() const { return (_u._data == Double); } 184 bool is_long2() const { return (_u._data == Long_2nd); } 185 bool is_double2() const { return (_u._data == Double_2nd); } 186 bool is_reference() const { return ((_u._data & TypeMask) == Reference); } 187 bool is_category1() const { 188 // This should return true for all one-word types, which are category1 189 // primitives, and references (including uninitialized refs). Though 190 // the 'query' types should technically return 'false' here, if we 191 // allow this to return true, we can perform the test using only 192 // 2 operations rather than 8 (3 masks, 3 compares and 2 logical 'ands'). 193 // Since noone should call this on a query type anyway, this is ok. 194 assert(!is_check(), "Must not be a check type (wrong value returned)"); 195 return ((_u._data & Category1) != Primitive); 196 // should only return false if it's a primitive, and the category1 flag 197 // is not set. 198 } 199 bool is_category2() const { return ((_u._data & Category2) == Category2); } 200 bool is_category2_2nd() const { 201 return ((_u._data & Category2_2nd) == Category2_2nd); 202 } 203 bool is_reference_check() const { return _u._data == ReferenceQuery; } 204 bool is_category1_check() const { return _u._data == Category1Query; } 205 bool is_category2_check() const { return _u._data == Category2Query; } 206 bool is_category2_2nd_check() const { return _u._data == Category2_2ndQuery; } 207 bool is_check() const { return (_u._data & TypeQuery) == TypeQuery; } 208 209 bool is_x_array(char sig) const { 210 return is_null() || (is_array() && (name()->byte_at(1) == sig)); 211 } 212 bool is_int_array() const { return is_x_array('I'); } 213 bool is_byte_array() const { return is_x_array('B'); } 214 bool is_bool_array() const { return is_x_array('Z'); } 215 bool is_char_array() const { return is_x_array('C'); } 216 bool is_short_array() const { return is_x_array('S'); } 217 bool is_long_array() const { return is_x_array('J'); } 218 bool is_float_array() const { return is_x_array('F'); } 219 bool is_double_array() const { return is_x_array('D'); } 220 bool is_object_array() const { return is_x_array('L'); } 221 bool is_array_array() const { return is_x_array('['); } 222 bool is_reference_array() const 223 { return is_object_array() || is_array_array(); } 224 bool is_object() const 225 { return (is_reference() && !is_null() && name()->utf8_length() >= 1 && 226 name()->byte_at(0) != '['); } 227 bool is_array() const 228 { return (is_reference() && !is_null() && name()->utf8_length() >= 2 && 229 name()->byte_at(0) == '['); } 230 bool is_uninitialized() const 231 { return ((_u._data & Uninitialized) == Uninitialized); } 232 bool is_uninitialized_this() const 233 { return is_uninitialized() && bci() == BciForThis; } 234 235 VerificationType to_category2_2nd() const { 236 assert(is_category2(), "Must be a double word"); 237 return VerificationType(is_long() ? Long_2nd : Double_2nd); 238 } 239 240 u2 bci() const { 241 assert(is_uninitialized(), "Must be uninitialized type"); 242 return ((_u._data & BciMask) >> 1 * BitsPerByte); 243 } 244 245 Symbol* name() const { 246 assert(is_reference() && !is_null(), "Must be a non-null reference"); 247 return _u._sym; 248 } 249 250 bool equals(const VerificationType& t) const { 251 return (_u._data == t._u._data || 252 (is_reference() && t.is_reference() && !is_null() && !t.is_null() && 253 name() == t.name())); 254 } 255 256 bool operator ==(const VerificationType& t) const { 257 return equals(t); 258 } 259 260 bool operator !=(const VerificationType& t) const { 261 return !equals(t); 262 } 263 264 // The whole point of this type system - check to see if one type 265 // is assignable to another. Returns true if one can assign 'from' to 266 // this. 267 bool is_assignable_from( 268 const VerificationType& from, ClassVerifier* context, 269 bool from_field_is_protected, TRAPS) const { 270 if (equals(from) || is_bogus()) { 271 return true; 272 } else { 273 switch(_u._data) { 274 case Category1Query: 275 return from.is_category1(); 276 case Category2Query: 277 return from.is_category2(); 278 case Category2_2ndQuery: 279 return from.is_category2_2nd(); 280 case ReferenceQuery: 281 return from.is_reference() || from.is_uninitialized(); 282 case Boolean: 283 case Byte: 284 case Char: 285 case Short: 286 // An int can be assigned to boolean, byte, char or short values. 287 return from.is_integer(); 288 default: 289 if (is_reference() && from.is_reference()) { 290 return is_reference_assignable_from(from, context, 291 from_field_is_protected, 292 THREAD); 293 } else { 294 return false; 295 } 296 } 297 } 298 } 299 300 VerificationType get_component(ClassVerifier* context, TRAPS) const; 301 302 int dimensions() const { 303 assert(is_array(), "Must be an array"); 304 int index = 0; 305 while (name()->byte_at(index) == '[') index++; 306 return index; 307 } 308 309 void print_on(outputStream* st) const; 310 311 private: 312 313 bool is_reference_assignable_from( 314 const VerificationType&, ClassVerifier*, bool from_field_is_protected, 315 TRAPS) const; 316}; 317 318#endif // SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP 319