1 /* 2 * Copyright (C) 2015 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 "debugger_interface.h" 18 19 #include "base/logging.h" 20 #include "base/mutex.h" 21 #include "thread-inl.h" 22 #include "thread.h" 23 24 #include <unordered_map> 25 26 namespace art { 27 28 // ------------------------------------------------------------------- 29 // Binary GDB JIT Interface as described in 30 // http://sourceware.org/gdb/onlinedocs/gdb/Declarations.html 31 // ------------------------------------------------------------------- 32 extern "C" { 33 typedef enum { 34 JIT_NOACTION = 0, 35 JIT_REGISTER_FN, 36 JIT_UNREGISTER_FN 37 } JITAction; 38 39 struct JITCodeEntry { 40 JITCodeEntry* next_; 41 JITCodeEntry* prev_; 42 const uint8_t *symfile_addr_; 43 uint64_t symfile_size_; 44 }; 45 46 struct JITDescriptor { 47 uint32_t version_; 48 uint32_t action_flag_; 49 JITCodeEntry* relevant_entry_; 50 JITCodeEntry* first_entry_; 51 }; 52 53 // GDB will place breakpoint into this function. 54 // To prevent GCC from inlining or removing it we place noinline attribute 55 // and inline assembler statement inside. 56 void __attribute__((noinline)) __jit_debug_register_code(); 57 void __attribute__((noinline)) __jit_debug_register_code() { 58 __asm__(""); 59 } 60 61 // Call __jit_debug_register_code indirectly via global variable. 62 // This gives the debugger an easy way to inject custom code to handle the events. 63 void (*__jit_debug_register_code_ptr)() = __jit_debug_register_code; 64 65 // GDB will inspect contents of this descriptor. 66 // Static initialization is necessary to prevent GDB from seeing 67 // uninitialized descriptor. 68 JITDescriptor __jit_debug_descriptor = { 1, JIT_NOACTION, nullptr, nullptr }; 69 } 70 71 static Mutex g_jit_debug_mutex("JIT debug interface lock", kJitDebugInterfaceLock); 72 73 static JITCodeEntry* CreateJITCodeEntryInternal(std::vector<uint8_t> symfile) 74 REQUIRES(g_jit_debug_mutex) { 75 DCHECK_NE(symfile.size(), 0u); 76 77 // Make a copy of the buffer. We want to shrink it anyway. 78 uint8_t* symfile_copy = new uint8_t[symfile.size()]; 79 CHECK(symfile_copy != nullptr); 80 memcpy(symfile_copy, symfile.data(), symfile.size()); 81 82 JITCodeEntry* entry = new JITCodeEntry; 83 CHECK(entry != nullptr); 84 entry->symfile_addr_ = symfile_copy; 85 entry->symfile_size_ = symfile.size(); 86 entry->prev_ = nullptr; 87 88 entry->next_ = __jit_debug_descriptor.first_entry_; 89 if (entry->next_ != nullptr) { 90 entry->next_->prev_ = entry; 91 } 92 __jit_debug_descriptor.first_entry_ = entry; 93 __jit_debug_descriptor.relevant_entry_ = entry; 94 95 __jit_debug_descriptor.action_flag_ = JIT_REGISTER_FN; 96 (*__jit_debug_register_code_ptr)(); 97 return entry; 98 } 99 100 static void DeleteJITCodeEntryInternal(JITCodeEntry* entry) REQUIRES(g_jit_debug_mutex) { 101 if (entry->prev_ != nullptr) { 102 entry->prev_->next_ = entry->next_; 103 } else { 104 __jit_debug_descriptor.first_entry_ = entry->next_; 105 } 106 107 if (entry->next_ != nullptr) { 108 entry->next_->prev_ = entry->prev_; 109 } 110 111 __jit_debug_descriptor.relevant_entry_ = entry; 112 __jit_debug_descriptor.action_flag_ = JIT_UNREGISTER_FN; 113 (*__jit_debug_register_code_ptr)(); 114 delete[] entry->symfile_addr_; 115 delete entry; 116 } 117 118 JITCodeEntry* CreateJITCodeEntry(std::vector<uint8_t> symfile) { 119 Thread* self = Thread::Current(); 120 MutexLock mu(self, g_jit_debug_mutex); 121 return CreateJITCodeEntryInternal(std::move(symfile)); 122 } 123 124 void DeleteJITCodeEntry(JITCodeEntry* entry) { 125 Thread* self = Thread::Current(); 126 MutexLock mu(self, g_jit_debug_mutex); 127 DeleteJITCodeEntryInternal(entry); 128 } 129 130 // Mapping from address to entry. It takes ownership of the entries 131 // so that the user of the JIT interface does not have to store them. 132 static std::unordered_map<uintptr_t, JITCodeEntry*> g_jit_code_entries; 133 134 void CreateJITCodeEntryForAddress(uintptr_t address, std::vector<uint8_t> symfile) { 135 Thread* self = Thread::Current(); 136 MutexLock mu(self, g_jit_debug_mutex); 137 DCHECK_NE(address, 0u); 138 DCHECK(g_jit_code_entries.find(address) == g_jit_code_entries.end()); 139 JITCodeEntry* entry = CreateJITCodeEntryInternal(std::move(symfile)); 140 g_jit_code_entries.emplace(address, entry); 141 } 142 143 bool DeleteJITCodeEntryForAddress(uintptr_t address) { 144 Thread* self = Thread::Current(); 145 MutexLock mu(self, g_jit_debug_mutex); 146 const auto& it = g_jit_code_entries.find(address); 147 if (it == g_jit_code_entries.end()) { 148 return false; 149 } 150 DeleteJITCodeEntryInternal(it->second); 151 g_jit_code_entries.erase(it); 152 return true; 153 } 154 155 } // namespace art 156
