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 #ifndef ART_RUNTIME_NTH_CALLER_VISITOR_H_ 18 #define ART_RUNTIME_NTH_CALLER_VISITOR_H_ 19 20 #include "art_method.h" 21 #include "base/mutex.h" 22 #include "stack.h" 23 24 namespace art { 25 class Thread; 26 27 // Walks up the stack 'n' callers, when used with Thread::WalkStack. 28 struct NthCallerVisitor : public StackVisitor { 29 NthCallerVisitor(Thread* thread, size_t n_in, bool include_runtime_and_upcalls = false) 30 : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames), 31 n(n_in), 32 include_runtime_and_upcalls_(include_runtime_and_upcalls), 33 count(0), 34 caller(nullptr) {} 35 36 bool VisitFrame() SHARED_REQUIRES(Locks::mutator_lock_) { 37 ArtMethod* m = GetMethod(); 38 bool do_count = false; 39 if (m == nullptr || m->IsRuntimeMethod()) { 40 // Upcall. 41 do_count = include_runtime_and_upcalls_; 42 } else { 43 do_count = true; 44 } 45 if (do_count) { 46 DCHECK(caller == nullptr); 47 if (count == n) { 48 caller = m; 49 return false; 50 } 51 count++; 52 } 53 return true; 54 } 55 56 const size_t n; 57 const bool include_runtime_and_upcalls_; 58 size_t count; 59 ArtMethod* caller; 60 }; 61 62 } // namespace art 63 64 #endif // ART_RUNTIME_NTH_CALLER_VISITOR_H_ 65