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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "debugger_interface.h"
#include <android-base/logging.h>
#include "base/mutex.h"
#include "thread-current-inl.h"
#include "thread.h"
#include <unordered_map>
namespace art {
// -------------------------------------------------------------------
// Binary GDB JIT Interface as described in
// http://sourceware.org/gdb/onlinedocs/gdb/Declarations.html
// -------------------------------------------------------------------
extern "C" {
typedef enum {
JIT_NOACTION = 0,
JIT_REGISTER_FN,
JIT_UNREGISTER_FN
} JITAction;
struct JITCodeEntry {
JITCodeEntry* next_;
JITCodeEntry* prev_;
const uint8_t *symfile_addr_;
uint64_t symfile_size_;
uint32_t ref_count; // ART internal field.
};
struct JITDescriptor {
uint32_t version_;
uint32_t action_flag_;
JITCodeEntry* relevant_entry_;
JITCodeEntry* first_entry_;
};
// GDB will place breakpoint into this function.
// To prevent GCC from inlining or removing it we place noinline attribute
// and inline assembler statement inside.
void __attribute__((noinline)) __jit_debug_register_code();
void __attribute__((noinline)) __jit_debug_register_code() {
__asm__("");
}
// Call __jit_debug_register_code indirectly via global variable.
// This gives the debugger an easy way to inject custom code to handle the events.
void (*__jit_debug_register_code_ptr)() = __jit_debug_register_code;
// GDB will inspect contents of this descriptor.
// Static initialization is necessary to prevent GDB from seeing
// uninitialized descriptor.
JITDescriptor __jit_debug_descriptor = { 1, JIT_NOACTION, nullptr, nullptr };
// Incremented whenever __jit_debug_descriptor is modified.
uint32_t __jit_debug_descriptor_timestamp = 0;
struct DEXFileEntry {
DEXFileEntry* next_;
DEXFileEntry* prev_;
const void* dexfile_;
};
DEXFileEntry* __art_debug_dexfiles = nullptr;
// Incremented whenever __art_debug_dexfiles is modified.
uint32_t __art_debug_dexfiles_timestamp = 0;
}
static size_t g_jit_debug_mem_usage
GUARDED_BY(Locks::native_debug_interface_lock_) = 0;
static std::unordered_map<const void*, DEXFileEntry*> g_dexfile_entries
GUARDED_BY(Locks::native_debug_interface_lock_);
void RegisterDexFileForNative(Thread* current_thread, const void* dexfile_header) {
MutexLock mu(current_thread, *Locks::native_debug_interface_lock_);
if (g_dexfile_entries.count(dexfile_header) == 0) {
DEXFileEntry* entry = new DEXFileEntry();
CHECK(entry != nullptr);
entry->dexfile_ = dexfile_header;
entry->prev_ = nullptr;
entry->next_ = __art_debug_dexfiles;
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry;
}
__art_debug_dexfiles = entry;
__art_debug_dexfiles_timestamp++;
g_dexfile_entries.emplace(dexfile_header, entry);
}
}
void DeregisterDexFileForNative(Thread* current_thread, const void* dexfile_header) {
MutexLock mu(current_thread, *Locks::native_debug_interface_lock_);
auto it = g_dexfile_entries.find(dexfile_header);
// We register dex files in the class linker and free them in DexFile_closeDexFile,
// but might be cases where we load the dex file without using it in the class linker.
if (it != g_dexfile_entries.end()) {
DEXFileEntry* entry = it->second;
if (entry->prev_ != nullptr) {
entry->prev_->next_ = entry->next_;
} else {
__art_debug_dexfiles = entry->next_;
}
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry->prev_;
}
__art_debug_dexfiles_timestamp++;
delete entry;
g_dexfile_entries.erase(it);
}
}
JITCodeEntry* CreateJITCodeEntry(const std::vector<uint8_t>& symfile) {
DCHECK_NE(symfile.size(), 0u);
// Make a copy of the buffer. We want to shrink it anyway.
uint8_t* symfile_copy = new uint8_t[symfile.size()];
CHECK(symfile_copy != nullptr);
memcpy(symfile_copy, symfile.data(), symfile.size());
JITCodeEntry* entry = new JITCodeEntry;
CHECK(entry != nullptr);
entry->symfile_addr_ = symfile_copy;
entry->symfile_size_ = symfile.size();
entry->prev_ = nullptr;
entry->ref_count = 0;
entry->next_ = __jit_debug_descriptor.first_entry_;
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry;
}
g_jit_debug_mem_usage += sizeof(JITCodeEntry) + entry->symfile_size_;
__jit_debug_descriptor.first_entry_ = entry;
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_REGISTER_FN;
__jit_debug_descriptor_timestamp++;
(*__jit_debug_register_code_ptr)();
return entry;
}
void DeleteJITCodeEntry(JITCodeEntry* entry) {
if (entry->prev_ != nullptr) {
entry->prev_->next_ = entry->next_;
} else {
__jit_debug_descriptor.first_entry_ = entry->next_;
}
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry->prev_;
}
g_jit_debug_mem_usage -= sizeof(JITCodeEntry) + entry->symfile_size_;
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_UNREGISTER_FN;
__jit_debug_descriptor_timestamp++;
(*__jit_debug_register_code_ptr)();
delete[] entry->symfile_addr_;
delete entry;
}
// Mapping from code address to entry. Used to manage life-time of the entries.
static std::unordered_map<uintptr_t, JITCodeEntry*> g_jit_code_entries
GUARDED_BY(Locks::native_debug_interface_lock_);
void IncrementJITCodeEntryRefcount(JITCodeEntry* entry, uintptr_t code_address) {
DCHECK(entry != nullptr);
DCHECK_EQ(g_jit_code_entries.count(code_address), 0u);
entry->ref_count++;
g_jit_code_entries.emplace(code_address, entry);
}
void DecrementJITCodeEntryRefcount(JITCodeEntry* entry, uintptr_t code_address) {
DCHECK(entry != nullptr);
DCHECK(g_jit_code_entries[code_address] == entry);
if (--entry->ref_count == 0) {
DeleteJITCodeEntry(entry);
}
g_jit_code_entries.erase(code_address);
}
JITCodeEntry* GetJITCodeEntry(uintptr_t code_address) {
auto it = g_jit_code_entries.find(code_address);
return it == g_jit_code_entries.end() ? nullptr : it->second;
}
size_t GetJITCodeEntryMemUsage() {
return g_jit_debug_mem_usage + g_jit_code_entries.size() * 2 * sizeof(void*);
}
} // namespace art
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