217 // The frame code should completely validate the frame so that 218 // references to Method* and bci are completely safe to access 219 // If they aren't the frame code should be fixed not this 220 // code. However since gc isn't locked out the values could be 221 // stale. This is a race we can never completely win since we can't 222 // lock out gc so do one last check after retrieving their values 223 // from the frame for additional safety 224 225 Method* method = fr->interpreter_frame_method(); 226 227 // We've at least found a method. 228 // NOTE: there is something to be said for the approach that 229 // if we don't find a valid bci then the method is not likely 230 // a valid method. Then again we may have caught an interpreter 231 // frame in the middle of construction and the bci field is 232 // not yet valid. 233 234 *method_p = method; 235 if (!method->is_valid_method()) return false; 236 237 intptr_t bcx = fr->interpreter_frame_bcx(); 238 239 int bci = method->validate_bci_from_bcx(bcx); 240 241 // note: bci is set to -1 if not a valid bci 242 *bci_p = bci; 243 return true; 244 } 245 246 return false; 247 } 248 249 250 // Determine if 'fr' can be used to find an initial Java frame. 251 // Return false if it can not find a fully decipherable Java frame 252 // (in other words a frame that isn't safe to use in a vframe stream). 253 // Obviously if it can't even find a Java frame false will also be returned. 254 // 255 // If we find a Java frame decipherable or not then by definition we have 256 // identified a method and that will be returned to the caller via method_p. 257 // If we can determine a bci that is returned also. (Hmm is it possible 258 // to return a method and bci and still return false? ) 259 // | 217 // The frame code should completely validate the frame so that 218 // references to Method* and bci are completely safe to access 219 // If they aren't the frame code should be fixed not this 220 // code. However since gc isn't locked out the values could be 221 // stale. This is a race we can never completely win since we can't 222 // lock out gc so do one last check after retrieving their values 223 // from the frame for additional safety 224 225 Method* method = fr->interpreter_frame_method(); 226 227 // We've at least found a method. 228 // NOTE: there is something to be said for the approach that 229 // if we don't find a valid bci then the method is not likely 230 // a valid method. Then again we may have caught an interpreter 231 // frame in the middle of construction and the bci field is 232 // not yet valid. 233 234 *method_p = method; 235 if (!method->is_valid_method()) return false; 236 237 address bcp = fr->interpreter_frame_bcp(); 238 int bci = method->validate_bci_from_bcp(bcp); 239 240 // note: bci is set to -1 if not a valid bci 241 *bci_p = bci; 242 return true; 243 } 244 245 return false; 246 } 247 248 249 // Determine if 'fr' can be used to find an initial Java frame. 250 // Return false if it can not find a fully decipherable Java frame 251 // (in other words a frame that isn't safe to use in a vframe stream). 252 // Obviously if it can't even find a Java frame false will also be returned. 253 // 254 // If we find a Java frame decipherable or not then by definition we have 255 // identified a method and that will be returned to the caller via method_p. 256 // If we can determine a bci that is returned also. (Hmm is it possible 257 // to return a method and bci and still return false? ) 258 // |