1093 }
1094
1095 #define INVALID_BYTECODE_ENCOUNTERED -1
1096 #define NPE_EXPLICIT_CONSTRUCTED -2
1097 int ExceptionMessageBuilder::get_NPE_null_slot(int bci) {
1098 // Get the bytecode.
1099 address code_base = _method->constMethod()->code_base();
1100 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + bci);
1101 int pos = bci + 1; // Position of argument of the bytecode.
1102 if (code == Bytecodes::_wide) {
1103 code = Bytecodes::java_code_at(_method, code_base + bci + 1);
1104 pos += 1;
1105 }
1106
1107 switch (code) {
1108 case Bytecodes::_getfield:
1109 case Bytecodes::_arraylength:
1110 case Bytecodes::_athrow:
1111 case Bytecodes::_monitorenter:
1112 case Bytecodes::_monitorexit:
1113 return 0;
1114 case Bytecodes::_iaload:
1115 case Bytecodes::_faload:
1116 case Bytecodes::_aaload:
1117 case Bytecodes::_baload:
1118 case Bytecodes::_caload:
1119 case Bytecodes::_saload:
1120 case Bytecodes::_laload:
1121 case Bytecodes::_daload:
1122 return 1;
1123 case Bytecodes::_iastore:
1124 case Bytecodes::_fastore:
1125 case Bytecodes::_aastore:
1126 case Bytecodes::_bastore:
1127 case Bytecodes::_castore:
1128 case Bytecodes::_sastore:
1129 return 2;
1130 case Bytecodes::_lastore:
1131 case Bytecodes::_dastore:
1132 return 3;
1153 // messages for NullPointerExceptions created explicitly by new in Java code.
1154 if (name != vmSymbols::object_initializer_name()) {
1155 int type_index = cp->signature_ref_index_at(name_and_type_index);
1156 Symbol* signature = cp->symbol_at(type_index);
1157 // The 'this' parameter was null. Return the slot of it.
1158 return ArgumentSizeComputer(signature).size();
1159 } else {
1160 return NPE_EXPLICIT_CONSTRUCTED;
1161 }
1162 }
1163
1164 default:
1165 break;
1166 }
1167
1168 return INVALID_BYTECODE_ENCOUNTERED;
1169 }
1170
1171 bool ExceptionMessageBuilder::print_NPE_cause(outputStream* os, int bci, int slot) {
1172 if (print_NPE_cause0(os, bci, slot, _max_cause_detail, false, " because \"")) {
1173 os->print("\" is null");
1174 return true;
1175 }
1176 return false;
1177 }
1178
1179 // Recursively print what was null.
1180 //
1181 // Go to the bytecode that pushed slot 'slot' on the operand stack
1182 // at bytecode 'bci'. Compute a message for that bytecode. If
1183 // necessary (array, field), recur further.
1184 // At most do max_detail recursions.
1185 // Prefix is used to print a proper beginning of the whole
1186 // sentence.
1187 // inner_expr is used to omit some text, like 'static' in
1188 // inner expressions like array subscripts.
1189 //
1190 // Returns true if something was printed.
1191 //
1192 bool ExceptionMessageBuilder::print_NPE_cause0(outputStream* os, int bci, int slot,
1193 int max_detail,
1415 case Bytecodes::_getfield: {
1416 int cp_index = Bytes::get_native_u2(code_base + pos);
1417 ConstantPool* cp = _method->constants();
1418 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
1419 int name_index = cp->name_ref_index_at(name_and_type_index);
1420 Symbol* name = cp->symbol_at(name_index);
1421 os->print("Cannot read field \"%s\"", name->as_C_string());
1422 } break;
1423 case Bytecodes::_putfield: {
1424 int cp_index = Bytes::get_native_u2(code_base + pos);
1425 os->print("Cannot assign field \"%s\"", get_field_name(_method, cp_index, code));
1426 } break;
1427 case Bytecodes::_invokevirtual:
1428 case Bytecodes::_invokespecial:
1429 case Bytecodes::_invokeinterface: {
1430 int cp_index = Bytes::get_native_u2(code_base+ pos);
1431 os->print("Cannot invoke \"");
1432 print_method_name(os, _method, cp_index, code);
1433 os->print("\"");
1434 } break;
1435
1436 default:
1437 assert(0, "We should have checked this bytecode in get_NPE_null_slot().");
1438 break;
1439 }
1440 }
1441
1442 // Main API
1443 bool BytecodeUtils::get_NPE_message_at(outputStream* ss, Method* method, int bci) {
1444
1445 NoSafepointVerifier _nsv; // Cannot use this object over a safepoint.
1446
1447 // If this NPE was created via reflection, we have no real NPE.
1448 if (method->method_holder() ==
1449 vmClasses::reflect_DirectConstructorHandleAccessor_NativeAccessor_klass()) {
1450 return false;
1451 }
1452
1453 // Analyse the bytecodes.
1454 ResourceMark rm;
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1093 }
1094
1095 #define INVALID_BYTECODE_ENCOUNTERED -1
1096 #define NPE_EXPLICIT_CONSTRUCTED -2
1097 int ExceptionMessageBuilder::get_NPE_null_slot(int bci) {
1098 // Get the bytecode.
1099 address code_base = _method->constMethod()->code_base();
1100 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + bci);
1101 int pos = bci + 1; // Position of argument of the bytecode.
1102 if (code == Bytecodes::_wide) {
1103 code = Bytecodes::java_code_at(_method, code_base + bci + 1);
1104 pos += 1;
1105 }
1106
1107 switch (code) {
1108 case Bytecodes::_getfield:
1109 case Bytecodes::_arraylength:
1110 case Bytecodes::_athrow:
1111 case Bytecodes::_monitorenter:
1112 case Bytecodes::_monitorexit:
1113 case Bytecodes::_checkcast:
1114 return 0;
1115 case Bytecodes::_iaload:
1116 case Bytecodes::_faload:
1117 case Bytecodes::_aaload:
1118 case Bytecodes::_baload:
1119 case Bytecodes::_caload:
1120 case Bytecodes::_saload:
1121 case Bytecodes::_laload:
1122 case Bytecodes::_daload:
1123 return 1;
1124 case Bytecodes::_iastore:
1125 case Bytecodes::_fastore:
1126 case Bytecodes::_aastore:
1127 case Bytecodes::_bastore:
1128 case Bytecodes::_castore:
1129 case Bytecodes::_sastore:
1130 return 2;
1131 case Bytecodes::_lastore:
1132 case Bytecodes::_dastore:
1133 return 3;
1154 // messages for NullPointerExceptions created explicitly by new in Java code.
1155 if (name != vmSymbols::object_initializer_name()) {
1156 int type_index = cp->signature_ref_index_at(name_and_type_index);
1157 Symbol* signature = cp->symbol_at(type_index);
1158 // The 'this' parameter was null. Return the slot of it.
1159 return ArgumentSizeComputer(signature).size();
1160 } else {
1161 return NPE_EXPLICIT_CONSTRUCTED;
1162 }
1163 }
1164
1165 default:
1166 break;
1167 }
1168
1169 return INVALID_BYTECODE_ENCOUNTERED;
1170 }
1171
1172 bool ExceptionMessageBuilder::print_NPE_cause(outputStream* os, int bci, int slot) {
1173 if (print_NPE_cause0(os, bci, slot, _max_cause_detail, false, " because \"")) {
1174 address code_base = _method->constMethod()->code_base();
1175 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + bci);
1176 if (code == Bytecodes::_aastore) {
1177 os->print("\" is null or is a null-free array and there's an attempt to store null in it");
1178 } else {
1179 os->print("\" is null");
1180 }
1181 return true;
1182 }
1183 return false;
1184 }
1185
1186 // Recursively print what was null.
1187 //
1188 // Go to the bytecode that pushed slot 'slot' on the operand stack
1189 // at bytecode 'bci'. Compute a message for that bytecode. If
1190 // necessary (array, field), recur further.
1191 // At most do max_detail recursions.
1192 // Prefix is used to print a proper beginning of the whole
1193 // sentence.
1194 // inner_expr is used to omit some text, like 'static' in
1195 // inner expressions like array subscripts.
1196 //
1197 // Returns true if something was printed.
1198 //
1199 bool ExceptionMessageBuilder::print_NPE_cause0(outputStream* os, int bci, int slot,
1200 int max_detail,
1422 case Bytecodes::_getfield: {
1423 int cp_index = Bytes::get_native_u2(code_base + pos);
1424 ConstantPool* cp = _method->constants();
1425 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
1426 int name_index = cp->name_ref_index_at(name_and_type_index);
1427 Symbol* name = cp->symbol_at(name_index);
1428 os->print("Cannot read field \"%s\"", name->as_C_string());
1429 } break;
1430 case Bytecodes::_putfield: {
1431 int cp_index = Bytes::get_native_u2(code_base + pos);
1432 os->print("Cannot assign field \"%s\"", get_field_name(_method, cp_index, code));
1433 } break;
1434 case Bytecodes::_invokevirtual:
1435 case Bytecodes::_invokespecial:
1436 case Bytecodes::_invokeinterface: {
1437 int cp_index = Bytes::get_native_u2(code_base+ pos);
1438 os->print("Cannot invoke \"");
1439 print_method_name(os, _method, cp_index, code);
1440 os->print("\"");
1441 } break;
1442 case Bytecodes::_checkcast: {
1443 int cp_index = Bytes::get_Java_u2(code_base + pos);
1444 ConstantPool* cp = _method->constants();
1445 os->print("Cannot cast to null-free type \"%s\"", cp->klass_at_noresolve(cp_index)->as_C_string());
1446 } break;
1447
1448 default:
1449 assert(0, "We should have checked this bytecode in get_NPE_null_slot().");
1450 break;
1451 }
1452 }
1453
1454 // Main API
1455 bool BytecodeUtils::get_NPE_message_at(outputStream* ss, Method* method, int bci) {
1456
1457 NoSafepointVerifier _nsv; // Cannot use this object over a safepoint.
1458
1459 // If this NPE was created via reflection, we have no real NPE.
1460 if (method->method_holder() ==
1461 vmClasses::reflect_DirectConstructorHandleAccessor_NativeAccessor_klass()) {
1462 return false;
1463 }
1464
1465 // Analyse the bytecodes.
1466 ResourceMark rm;
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