Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "reg_type.h" |
| 18 | |
| 19 | #include "object_utils.h" |
| 20 | #include "reg_type_cache.h" |
| 21 | |
| 22 | namespace art { |
| 23 | namespace verifier { |
| 24 | |
| 25 | static const char* type_strings[] = { |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 26 | "Unknown", |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 27 | "Conflict", |
| 28 | "Boolean", |
| 29 | "Byte", |
| 30 | "Short", |
| 31 | "Char", |
| 32 | "Integer", |
| 33 | "Float", |
| 34 | "Long (Low Half)", |
| 35 | "Long (High Half)", |
| 36 | "Double (Low Half)", |
| 37 | "Double (High Half)", |
| 38 | "64-bit Constant (Low Half)", |
| 39 | "64-bit Constant (High Half)", |
| 40 | "32-bit Constant", |
| 41 | "Unresolved Reference", |
| 42 | "Uninitialized Reference", |
| 43 | "Uninitialized This Reference", |
| 44 | "Unresolved And Uninitialized Reference", |
| 45 | "Reference", |
| 46 | }; |
| 47 | |
| 48 | std::string RegType::Dump() const { |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 49 | DCHECK(type_ >= kRegTypeUnknown && type_ <= kRegTypeReference); |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 50 | std::string result; |
| 51 | if (IsConstant()) { |
| 52 | uint32_t val = ConstantValue(); |
| 53 | if (val == 0) { |
| 54 | result = "Zero"; |
| 55 | } else { |
| 56 | if (IsConstantShort()) { |
| 57 | result = StringPrintf("32-bit Constant: %d", val); |
| 58 | } else { |
| 59 | result = StringPrintf("32-bit Constant: 0x%x", val); |
| 60 | } |
| 61 | } |
| 62 | } else { |
| 63 | result = type_strings[type_]; |
| 64 | if (IsReferenceTypes()) { |
| 65 | result += ": "; |
| 66 | if (IsUnresolvedTypes()) { |
| 67 | result += PrettyDescriptor(GetDescriptor()); |
| 68 | } else { |
| 69 | result += PrettyDescriptor(GetClass()); |
| 70 | } |
| 71 | } |
| 72 | } |
| 73 | return result; |
| 74 | } |
| 75 | |
| 76 | const RegType& RegType::HighHalf(RegTypeCache* cache) const { |
| 77 | CHECK(IsLowHalf()); |
| 78 | if (type_ == kRegTypeLongLo) { |
| 79 | return cache->FromType(kRegTypeLongHi); |
| 80 | } else if (type_ == kRegTypeDoubleLo) { |
| 81 | return cache->FromType(kRegTypeDoubleHi); |
| 82 | } else { |
| 83 | return cache->FromType(kRegTypeConstHi); |
| 84 | } |
| 85 | } |
| 86 | |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 87 | /* |
| 88 | * A basic Join operation on classes. For a pair of types S and T the Join, written S v T = J, is |
| 89 | * S <: J, T <: J and for-all U such that S <: U, T <: U then J <: U. That is J is the parent of |
| 90 | * S and T such that there isn't a parent of both S and T that isn't also the parent of J (ie J |
| 91 | * is the deepest (lowest upper bound) parent of S and T). |
| 92 | * |
| 93 | * This operation applies for regular classes and arrays, however, for interface types there needn't |
| 94 | * be a partial ordering on the types. We could solve the problem of a lack of a partial order by |
| 95 | * introducing sets of types, however, the only operation permissible on an interface is |
| 96 | * invoke-interface. In the tradition of Java verifiers we defer the verification of interface |
| 97 | * types until an invoke-interface call on the interface typed reference at runtime and allow |
| 98 | * the perversion of any Object being assignable to an interface type (note, however, that we don't |
| 99 | * allow assignment of Object or Interface to any concrete subclass of Object and are therefore type |
| 100 | * safe; further the Join on a Object cannot result in a sub-class by definition). |
| 101 | */ |
| 102 | Class* RegType::ClassJoin(Class* s, Class* t) { |
| 103 | DCHECK(!s->IsPrimitive()) << PrettyClass(s); |
| 104 | DCHECK(!t->IsPrimitive()) << PrettyClass(t); |
| 105 | if (s == t) { |
| 106 | return s; |
| 107 | } else if (s->IsAssignableFrom(t)) { |
| 108 | return s; |
| 109 | } else if (t->IsAssignableFrom(s)) { |
| 110 | return t; |
| 111 | } else if (s->IsArrayClass() && t->IsArrayClass()) { |
| 112 | Class* s_ct = s->GetComponentType(); |
| 113 | Class* t_ct = t->GetComponentType(); |
| 114 | if (s_ct->IsPrimitive() || t_ct->IsPrimitive()) { |
| 115 | // Given the types aren't the same, if either array is of primitive types then the only |
| 116 | // common parent is java.lang.Object |
| 117 | Class* result = s->GetSuperClass(); // short-cut to java.lang.Object |
| 118 | DCHECK(result->IsObjectClass()); |
| 119 | return result; |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 120 | } |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 121 | Class* common_elem = ClassJoin(s_ct, t_ct); |
| 122 | ClassLinker* class_linker = Runtime::Current()->GetClassLinker(); |
| 123 | const ClassLoader* class_loader = s->GetClassLoader(); |
| 124 | std::string descriptor("["); |
| 125 | descriptor += ClassHelper(common_elem).GetDescriptor(); |
| 126 | Class* array_class = class_linker->FindClass(descriptor.c_str(), class_loader); |
| 127 | DCHECK(array_class != NULL); |
| 128 | return array_class; |
Ian Rogers | 0d60484 | 2012-04-16 14:50:24 -0700 | [diff] [blame] | 129 | } else { |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 130 | size_t s_depth = s->Depth(); |
| 131 | size_t t_depth = t->Depth(); |
| 132 | // Get s and t to the same depth in the hierarchy |
| 133 | if (s_depth > t_depth) { |
| 134 | while (s_depth > t_depth) { |
| 135 | s = s->GetSuperClass(); |
| 136 | s_depth--; |
| 137 | } |
Ian Rogers | 0d60484 | 2012-04-16 14:50:24 -0700 | [diff] [blame] | 138 | } else { |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 139 | while (t_depth > s_depth) { |
| 140 | t = t->GetSuperClass(); |
| 141 | t_depth--; |
| 142 | } |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 143 | } |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 144 | // Go up the hierarchy until we get to the common parent |
| 145 | while (s != t) { |
| 146 | s = s->GetSuperClass(); |
| 147 | t = t->GetSuperClass(); |
| 148 | } |
| 149 | return s; |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 150 | } |
| 151 | } |
| 152 | |
| 153 | bool RegType::IsAssignableFrom(const RegType& src) const { |
| 154 | if (Equals(src)) { |
| 155 | return true; |
| 156 | } else { |
| 157 | switch (GetType()) { |
| 158 | case RegType::kRegTypeBoolean: return src.IsBooleanTypes(); |
| 159 | case RegType::kRegTypeByte: return src.IsByteTypes(); |
| 160 | case RegType::kRegTypeShort: return src.IsShortTypes(); |
| 161 | case RegType::kRegTypeChar: return src.IsCharTypes(); |
| 162 | case RegType::kRegTypeInteger: return src.IsIntegralTypes(); |
| 163 | case RegType::kRegTypeFloat: return src.IsFloatTypes(); |
| 164 | case RegType::kRegTypeLongLo: return src.IsLongTypes(); |
| 165 | case RegType::kRegTypeDoubleLo: return src.IsDoubleTypes(); |
| 166 | default: |
| 167 | if (!IsReferenceTypes()) { |
| 168 | LOG(FATAL) << "Unexpected register type in IsAssignableFrom: '" << src << "'"; |
| 169 | } |
| 170 | if (src.IsZero()) { |
| 171 | return true; // all reference types can be assigned null |
| 172 | } else if (!src.IsReferenceTypes()) { |
| 173 | return false; // expect src to be a reference type |
| 174 | } else if (IsJavaLangObject()) { |
| 175 | return true; // all reference types can be assigned to Object |
| 176 | } else if (!IsUnresolvedTypes() && GetClass()->IsInterface()) { |
| 177 | return true; // We allow assignment to any interface, see comment in ClassJoin |
| 178 | } else if (IsJavaLangObjectArray()) { |
| 179 | return src.IsObjectArrayTypes(); // All reference arrays may be assigned to Object[] |
| 180 | } else if (!IsUnresolvedTypes() && !src.IsUnresolvedTypes() && |
| 181 | GetClass()->IsAssignableFrom(src.GetClass())) { |
| 182 | // We're assignable from the Class point-of-view |
| 183 | return true; |
| 184 | } else { |
| 185 | return false; |
| 186 | } |
| 187 | } |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | static const RegType& SelectNonConstant(const RegType& a, const RegType& b) { |
| 192 | return a.IsConstant() ? b : a; |
| 193 | } |
| 194 | |
| 195 | const RegType& RegType::Merge(const RegType& incoming_type, RegTypeCache* reg_types) const { |
| 196 | DCHECK(!Equals(incoming_type)); // Trivial equality handled by caller |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 197 | if (IsUnknown() && incoming_type.IsUnknown()) { |
| 198 | return *this; // Unknown MERGE Unknown => Unknown |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 199 | } else if (IsConflict()) { |
| 200 | return *this; // Conflict MERGE * => Conflict |
| 201 | } else if (incoming_type.IsConflict()) { |
| 202 | return incoming_type; // * MERGE Conflict => Conflict |
Ian Rogers | e1758fe | 2012-04-19 11:31:15 -0700 | [diff] [blame^] | 203 | } else if (IsUnknown() || incoming_type.IsUnknown()) { |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 204 | return reg_types->Conflict(); // Unknown MERGE * => Conflict |
| 205 | } else if (IsConstant() && incoming_type.IsConstant()) { |
| 206 | int32_t val1 = ConstantValue(); |
| 207 | int32_t val2 = incoming_type.ConstantValue(); |
| 208 | if (val1 >= 0 && val2 >= 0) { |
| 209 | // +ve1 MERGE +ve2 => MAX(+ve1, +ve2) |
| 210 | if (val1 >= val2) { |
| 211 | return *this; |
| 212 | } else { |
| 213 | return incoming_type; |
| 214 | } |
| 215 | } else if (val1 < 0 && val2 < 0) { |
| 216 | // -ve1 MERGE -ve2 => MIN(-ve1, -ve2) |
| 217 | if (val1 <= val2) { |
| 218 | return *this; |
| 219 | } else { |
| 220 | return incoming_type; |
| 221 | } |
| 222 | } else { |
| 223 | // Values are +ve and -ve, choose smallest signed type in which they both fit |
| 224 | if (IsConstantByte()) { |
| 225 | if (incoming_type.IsConstantByte()) { |
| 226 | return reg_types->ByteConstant(); |
| 227 | } else if (incoming_type.IsConstantShort()) { |
| 228 | return reg_types->ShortConstant(); |
| 229 | } else { |
| 230 | return reg_types->IntConstant(); |
| 231 | } |
| 232 | } else if (IsConstantShort()) { |
| 233 | if (incoming_type.IsConstantShort()) { |
| 234 | return reg_types->ShortConstant(); |
| 235 | } else { |
| 236 | return reg_types->IntConstant(); |
| 237 | } |
| 238 | } else { |
| 239 | return reg_types->IntConstant(); |
| 240 | } |
| 241 | } |
| 242 | } else if (IsIntegralTypes() && incoming_type.IsIntegralTypes()) { |
| 243 | if (IsBooleanTypes() && incoming_type.IsBooleanTypes()) { |
| 244 | return reg_types->Boolean(); // boolean MERGE boolean => boolean |
| 245 | } |
| 246 | if (IsByteTypes() && incoming_type.IsByteTypes()) { |
| 247 | return reg_types->Byte(); // byte MERGE byte => byte |
| 248 | } |
| 249 | if (IsShortTypes() && incoming_type.IsShortTypes()) { |
| 250 | return reg_types->Short(); // short MERGE short => short |
| 251 | } |
| 252 | if (IsCharTypes() && incoming_type.IsCharTypes()) { |
| 253 | return reg_types->Char(); // char MERGE char => char |
| 254 | } |
| 255 | return reg_types->Integer(); // int MERGE * => int |
| 256 | } else if ((IsFloatTypes() && incoming_type.IsFloatTypes()) || |
| 257 | (IsLongTypes() && incoming_type.IsLongTypes()) || |
| 258 | (IsLongHighTypes() && incoming_type.IsLongHighTypes()) || |
| 259 | (IsDoubleTypes() && incoming_type.IsDoubleTypes()) || |
| 260 | (IsDoubleHighTypes() && incoming_type.IsDoubleHighTypes())) { |
| 261 | // check constant case was handled prior to entry |
| 262 | DCHECK(!IsConstant() || !incoming_type.IsConstant()); |
| 263 | // float/long/double MERGE float/long/double_constant => float/long/double |
| 264 | return SelectNonConstant(*this, incoming_type); |
| 265 | } else if (IsReferenceTypes() && incoming_type.IsReferenceTypes()) { |
| 266 | if (IsZero() || incoming_type.IsZero()) { |
| 267 | return SelectNonConstant(*this, incoming_type); // 0 MERGE ref => ref |
| 268 | } else if (IsJavaLangObject() || incoming_type.IsJavaLangObject()) { |
| 269 | return reg_types->JavaLangObject(); // Object MERGE ref => Object |
| 270 | } else if (IsUninitializedTypes() || incoming_type.IsUninitializedTypes() || |
| 271 | IsUnresolvedTypes() || incoming_type.IsUnresolvedTypes()) { |
| 272 | // Can only merge an unresolved or uninitialized type with itself, 0 or Object, we've already |
| 273 | // checked these so => Conflict |
| 274 | return reg_types->Conflict(); |
| 275 | } else { // Two reference types, compute Join |
| 276 | Class* c1 = GetClass(); |
| 277 | Class* c2 = incoming_type.GetClass(); |
| 278 | DCHECK(c1 != NULL && !c1->IsPrimitive()); |
| 279 | DCHECK(c2 != NULL && !c2->IsPrimitive()); |
| 280 | Class* join_class = ClassJoin(c1, c2); |
| 281 | if (c1 == join_class) { |
| 282 | return *this; |
| 283 | } else if (c2 == join_class) { |
| 284 | return incoming_type; |
| 285 | } else { |
| 286 | return reg_types->FromClass(join_class); |
| 287 | } |
| 288 | } |
| 289 | } else { |
| 290 | return reg_types->Conflict(); // Unexpected types => Conflict |
| 291 | } |
| 292 | } |
| 293 | |
Ian Rogers | 776ac1f | 2012-04-13 23:36:36 -0700 | [diff] [blame] | 294 | std::ostream& operator<<(std::ostream& os, const RegType& rhs) { |
| 295 | os << rhs.Dump(); |
| 296 | return os; |
| 297 | } |
| 298 | |
| 299 | } // verifier |
| 300 | } // art |