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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 "base/logging.h"
#include "base/mutex.h"
#include "thread-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_;
};
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 };
}
static Mutex g_jit_debug_mutex("JIT debug interface lock", kJitDebugInterfaceLock);
static JITCodeEntry* CreateJITCodeEntryInternal(std::vector<uint8_t> symfile)
REQUIRES(g_jit_debug_mutex) {
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->next_ = __jit_debug_descriptor.first_entry_;
if (entry->next_ != nullptr) {
entry->next_->prev_ = entry;
}
__jit_debug_descriptor.first_entry_ = entry;
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_REGISTER_FN;
(*__jit_debug_register_code_ptr)();
return entry;
}
static void DeleteJITCodeEntryInternal(JITCodeEntry* entry) REQUIRES(g_jit_debug_mutex) {
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_;
}
__jit_debug_descriptor.relevant_entry_ = entry;
__jit_debug_descriptor.action_flag_ = JIT_UNREGISTER_FN;
(*__jit_debug_register_code_ptr)();
delete[] entry->symfile_addr_;
delete entry;
}
JITCodeEntry* CreateJITCodeEntry(std::vector<uint8_t> symfile) {
Thread* self = Thread::Current();
MutexLock mu(self, g_jit_debug_mutex);
return CreateJITCodeEntryInternal(std::move(symfile));
}
void DeleteJITCodeEntry(JITCodeEntry* entry) {
Thread* self = Thread::Current();
MutexLock mu(self, g_jit_debug_mutex);
DeleteJITCodeEntryInternal(entry);
}
// Mapping from address to entry. It takes ownership of the entries
// so that the user of the JIT interface does not have to store them.
static std::unordered_map<uintptr_t, JITCodeEntry*> g_jit_code_entries;
void CreateJITCodeEntryForAddress(uintptr_t address, std::vector<uint8_t> symfile) {
Thread* self = Thread::Current();
MutexLock mu(self, g_jit_debug_mutex);
DCHECK_NE(address, 0u);
DCHECK(g_jit_code_entries.find(address) == g_jit_code_entries.end());
JITCodeEntry* entry = CreateJITCodeEntryInternal(std::move(symfile));
g_jit_code_entries.emplace(address, entry);
}
bool DeleteJITCodeEntryForAddress(uintptr_t address) {
Thread* self = Thread::Current();
MutexLock mu(self, g_jit_debug_mutex);
const auto it = g_jit_code_entries.find(address);
if (it == g_jit_code_entries.end()) {
return false;
}
DeleteJITCodeEntryInternal(it->second);
g_jit_code_entries.erase(it);
return true;
}
} // namespace art
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