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//===-- JITLoaderGDB.cpp --------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "JITLoaderGDB.h"
#include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Section.h"
#include "lldb/Interpreter/OptionValueProperties.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/SymbolVendor.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/StreamString.h"
#include "llvm/Support/MathExtras.h"
#include <memory>
using namespace lldb;
using namespace lldb_private;
LLDB_PLUGIN_DEFINE(JITLoaderGDB)
// Debug Interface Structures
enum jit_actions_t { JIT_NOACTION = 0, JIT_REGISTER_FN, JIT_UNREGISTER_FN };
template <typename ptr_t> struct jit_code_entry {
ptr_t next_entry; // pointer
ptr_t prev_entry; // pointer
ptr_t symfile_addr; // pointer
uint64_t symfile_size;
};
template <typename ptr_t> struct jit_descriptor {
uint32_t version;
uint32_t action_flag; // Values are jit_action_t
ptr_t relevant_entry; // pointer
ptr_t first_entry; // pointer
};
namespace {
enum EnableJITLoaderGDB {
eEnableJITLoaderGDBDefault,
eEnableJITLoaderGDBOn,
eEnableJITLoaderGDBOff,
};
static constexpr OptionEnumValueElement g_enable_jit_loader_gdb_enumerators[] =
{
{
eEnableJITLoaderGDBDefault,
"default",
"Enable JIT compilation interface for all platforms except macOS",
},
{
eEnableJITLoaderGDBOn,
"on",
"Enable JIT compilation interface",
},
{
eEnableJITLoaderGDBOff,
"off",
"Disable JIT compilation interface",
},
};
#define LLDB_PROPERTIES_jitloadergdb
#include "JITLoaderGDBProperties.inc"
enum {
#define LLDB_PROPERTIES_jitloadergdb
#include "JITLoaderGDBPropertiesEnum.inc"
ePropertyEnableJITBreakpoint
};
class PluginProperties : public Properties {
public:
static ConstString GetSettingName() {
return JITLoaderGDB::GetPluginNameStatic();
}
PluginProperties() {
m_collection_sp = std::make_shared<OptionValueProperties>(GetSettingName());
m_collection_sp->Initialize(g_jitloadergdb_properties);
}
EnableJITLoaderGDB GetEnable() const {
return (EnableJITLoaderGDB)m_collection_sp->GetPropertyAtIndexAsEnumeration(
nullptr, ePropertyEnable,
g_jitloadergdb_properties[ePropertyEnable].default_uint_value);
}
};
typedef std::shared_ptr<PluginProperties> JITLoaderGDBPropertiesSP;
static const JITLoaderGDBPropertiesSP &GetGlobalPluginProperties() {
static const auto g_settings_sp(std::make_shared<PluginProperties>());
return g_settings_sp;
}
template <typename ptr_t>
bool ReadJITEntry(const addr_t from_addr, Process *process,
jit_code_entry<ptr_t> *entry) {
lldbassert(from_addr % sizeof(ptr_t) == 0);
ArchSpec::Core core = process->GetTarget().GetArchitecture().GetCore();
bool i386_target = ArchSpec::kCore_x86_32_first <= core &&
core <= ArchSpec::kCore_x86_32_last;
uint8_t uint64_align_bytes = i386_target ? 4 : 8;
const size_t data_byte_size =
llvm::alignTo(sizeof(ptr_t) * 3, uint64_align_bytes) + sizeof(uint64_t);
Status error;
DataBufferHeap data(data_byte_size, 0);
size_t bytes_read = process->ReadMemory(from_addr, data.GetBytes(),
data.GetByteSize(), error);
if (bytes_read != data_byte_size || !error.Success())
return false;
DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
process->GetByteOrder(), sizeof(ptr_t));
lldb::offset_t offset = 0;
entry->next_entry = extractor.GetAddress(&offset);
entry->prev_entry = extractor.GetAddress(&offset);
entry->symfile_addr = extractor.GetAddress(&offset);
offset = llvm::alignTo(offset, uint64_align_bytes);
entry->symfile_size = extractor.GetU64(&offset);
return true;
}
} // anonymous namespace end
JITLoaderGDB::JITLoaderGDB(lldb_private::Process *process)
: JITLoader(process), m_jit_objects(),
m_jit_break_id(LLDB_INVALID_BREAK_ID),
m_jit_descriptor_addr(LLDB_INVALID_ADDRESS) {}
JITLoaderGDB::~JITLoaderGDB() {
if (LLDB_BREAK_ID_IS_VALID(m_jit_break_id))
m_process->GetTarget().RemoveBreakpointByID(m_jit_break_id);
}
void JITLoaderGDB::DebuggerInitialize(Debugger &debugger) {
if (!PluginManager::GetSettingForJITLoaderPlugin(
debugger, PluginProperties::GetSettingName())) {
const bool is_global_setting = true;
PluginManager::CreateSettingForJITLoaderPlugin(
debugger, GetGlobalPluginProperties()->GetValueProperties(),
ConstString("Properties for the JIT LoaderGDB plug-in."),
is_global_setting);
}
}
void JITLoaderGDB::DidAttach() {
Target &target = m_process->GetTarget();
ModuleList &module_list = target.GetImages();
SetJITBreakpoint(module_list);
}
void JITLoaderGDB::DidLaunch() {
Target &target = m_process->GetTarget();
ModuleList &module_list = target.GetImages();
SetJITBreakpoint(module_list);
}
void JITLoaderGDB::ModulesDidLoad(ModuleList &module_list) {
if (!DidSetJITBreakpoint() && m_process->IsAlive())
SetJITBreakpoint(module_list);
}
// Setup the JIT Breakpoint
void JITLoaderGDB::SetJITBreakpoint(lldb_private::ModuleList &module_list) {
if (DidSetJITBreakpoint())
return;
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_JIT_LOADER));
LLDB_LOGF(log, "JITLoaderGDB::%s looking for JIT register hook",
__FUNCTION__);
addr_t jit_addr = GetSymbolAddress(
module_list, ConstString("__jit_debug_register_code"), eSymbolTypeAny);
if (jit_addr == LLDB_INVALID_ADDRESS)
return;
m_jit_descriptor_addr = GetSymbolAddress(
module_list, ConstString("__jit_debug_descriptor"), eSymbolTypeData);
if (m_jit_descriptor_addr == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(log, "JITLoaderGDB::%s failed to find JIT descriptor address",
__FUNCTION__);
return;
}
LLDB_LOGF(log, "JITLoaderGDB::%s setting JIT breakpoint", __FUNCTION__);
Breakpoint *bp =
m_process->GetTarget().CreateBreakpoint(jit_addr, true, false).get();
bp->SetCallback(JITDebugBreakpointHit, this, true);
bp->SetBreakpointKind("jit-debug-register");
m_jit_break_id = bp->GetID();
ReadJITDescriptor(true);
}
bool JITLoaderGDB::JITDebugBreakpointHit(void *baton,
StoppointCallbackContext *context,
user_id_t break_id,
user_id_t break_loc_id) {
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_JIT_LOADER));
LLDB_LOGF(log, "JITLoaderGDB::%s hit JIT breakpoint", __FUNCTION__);
JITLoaderGDB *instance = static_cast<JITLoaderGDB *>(baton);
return instance->ReadJITDescriptor(false);
}
static void updateSectionLoadAddress(const SectionList &section_list,
Target &target, uint64_t symbolfile_addr,
uint64_t symbolfile_size,
uint64_t &vmaddrheuristic,
uint64_t &min_addr, uint64_t &max_addr) {
const uint32_t num_sections = section_list.GetSize();
for (uint32_t i = 0; i < num_sections; ++i) {
SectionSP section_sp(section_list.GetSectionAtIndex(i));
if (section_sp) {
if (section_sp->IsFake()) {
uint64_t lower = (uint64_t)-1;
uint64_t upper = 0;
updateSectionLoadAddress(section_sp->GetChildren(), target,
symbolfile_addr, symbolfile_size,
vmaddrheuristic, lower, upper);
if (lower < min_addr)
min_addr = lower;
if (upper > max_addr)
max_addr = upper;
const lldb::addr_t slide_amount = lower - section_sp->GetFileAddress();
section_sp->Slide(slide_amount, false);
section_sp->GetChildren().Slide(-slide_amount, false);
section_sp->SetByteSize(upper - lower);
} else {
vmaddrheuristic += 2 << section_sp->GetLog2Align();
uint64_t lower;
if (section_sp->GetFileAddress() > vmaddrheuristic)
lower = section_sp->GetFileAddress();
else {
lower = symbolfile_addr + section_sp->GetFileOffset();
section_sp->SetFileAddress(symbolfile_addr +
section_sp->GetFileOffset());
}
target.SetSectionLoadAddress(section_sp, lower, true);
uint64_t upper = lower + section_sp->GetByteSize();
if (lower < min_addr)
min_addr = lower;
if (upper > max_addr)
max_addr = upper;
// This is an upper bound, but a good enough heuristic
vmaddrheuristic += section_sp->GetByteSize();
}
}
}
}
bool JITLoaderGDB::ReadJITDescriptor(bool all_entries) {
if (m_process->GetTarget().GetArchitecture().GetAddressByteSize() == 8)
return ReadJITDescriptorImpl<uint64_t>(all_entries);
else
return ReadJITDescriptorImpl<uint32_t>(all_entries);
}
template <typename ptr_t>
bool JITLoaderGDB::ReadJITDescriptorImpl(bool all_entries) {
if (m_jit_descriptor_addr == LLDB_INVALID_ADDRESS)
return false;
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_JIT_LOADER));
Target &target = m_process->GetTarget();
ModuleList &module_list = target.GetImages();
jit_descriptor<ptr_t> jit_desc;
const size_t jit_desc_size = sizeof(jit_desc);
Status error;
size_t bytes_read = m_process->DoReadMemory(m_jit_descriptor_addr, &jit_desc,
jit_desc_size, error);
if (bytes_read != jit_desc_size || !error.Success()) {
LLDB_LOGF(log, "JITLoaderGDB::%s failed to read JIT descriptor",
__FUNCTION__);
return false;
}
jit_actions_t jit_action = (jit_actions_t)jit_desc.action_flag;
addr_t jit_relevant_entry = (addr_t)jit_desc.relevant_entry;
if (all_entries) {
jit_action = JIT_REGISTER_FN;
jit_relevant_entry = (addr_t)jit_desc.first_entry;
}
while (jit_relevant_entry != 0) {
jit_code_entry<ptr_t> jit_entry;
if (!ReadJITEntry(jit_relevant_entry, m_process, &jit_entry)) {
LLDB_LOGF(log, "JITLoaderGDB::%s failed to read JIT entry at 0x%" PRIx64,
__FUNCTION__, jit_relevant_entry);
return false;
}
const addr_t &symbolfile_addr = (addr_t)jit_entry.symfile_addr;
const size_t &symbolfile_size = (size_t)jit_entry.symfile_size;
ModuleSP module_sp;
if (jit_action == JIT_REGISTER_FN) {
LLDB_LOGF(log,
"JITLoaderGDB::%s registering JIT entry at 0x%" PRIx64
" (%" PRIu64 " bytes)",
__FUNCTION__, symbolfile_addr, (uint64_t)symbolfile_size);
char jit_name[64];
snprintf(jit_name, 64, "JIT(0x%" PRIx64 ")", symbolfile_addr);
module_sp = m_process->ReadModuleFromMemory(
FileSpec(jit_name), symbolfile_addr, symbolfile_size);
if (module_sp && module_sp->GetObjectFile()) {
// Object formats (like ELF) have no representation for a JIT type.
// We will get it wrong, if we deduce it from the header.
module_sp->GetObjectFile()->SetType(ObjectFile::eTypeJIT);
// load the symbol table right away
module_sp->GetObjectFile()->GetSymtab();
m_jit_objects.insert(std::make_pair(symbolfile_addr, module_sp));
if (auto image_object_file =
llvm::dyn_cast<ObjectFileMachO>(module_sp->GetObjectFile())) {
const SectionList *section_list = image_object_file->GetSectionList();
if (section_list) {
uint64_t vmaddrheuristic = 0;
uint64_t lower = (uint64_t)-1;
uint64_t upper = 0;
updateSectionLoadAddress(*section_list, target, symbolfile_addr,
symbolfile_size, vmaddrheuristic, lower,
upper);
}
} else {
bool changed = false;
module_sp->SetLoadAddress(target, 0, true, changed);
}
module_list.AppendIfNeeded(module_sp);
ModuleList module_list;
module_list.Append(module_sp);
target.ModulesDidLoad(module_list);
} else {
LLDB_LOGF(log,
"JITLoaderGDB::%s failed to load module for "
"JIT entry at 0x%" PRIx64,
__FUNCTION__, symbolfile_addr);
}
} else if (jit_action == JIT_UNREGISTER_FN) {
LLDB_LOGF(log, "JITLoaderGDB::%s unregistering JIT entry at 0x%" PRIx64,
__FUNCTION__, symbolfile_addr);
JITObjectMap::iterator it = m_jit_objects.find(symbolfile_addr);
if (it != m_jit_objects.end()) {
module_sp = it->second;
ObjectFile *image_object_file = module_sp->GetObjectFile();
if (image_object_file) {
const SectionList *section_list = image_object_file->GetSectionList();
if (section_list) {
const uint32_t num_sections = section_list->GetSize();
for (uint32_t i = 0; i < num_sections; ++i) {
SectionSP section_sp(section_list->GetSectionAtIndex(i));
if (section_sp) {
target.GetSectionLoadList().SetSectionUnloaded(section_sp);
}
}
}
}
module_list.Remove(module_sp);
m_jit_objects.erase(it);
}
} else if (jit_action == JIT_NOACTION) {
// Nothing to do
} else {
assert(false && "Unknown jit action");
}
if (all_entries)
jit_relevant_entry = (addr_t)jit_entry.next_entry;
else
jit_relevant_entry = 0;
}
return false; // Continue Running.
}
// PluginInterface protocol
lldb_private::ConstString JITLoaderGDB::GetPluginNameStatic() {
static ConstString g_name("gdb");
return g_name;
}
JITLoaderSP JITLoaderGDB::CreateInstance(Process *process, bool force) {
JITLoaderSP jit_loader_sp;
bool enable;
switch (GetGlobalPluginProperties()->GetEnable()) {
case EnableJITLoaderGDB::eEnableJITLoaderGDBOn:
enable = true;
break;
case EnableJITLoaderGDB::eEnableJITLoaderGDBOff:
enable = false;
break;
case EnableJITLoaderGDB::eEnableJITLoaderGDBDefault:
ArchSpec arch(process->GetTarget().GetArchitecture());
enable = arch.GetTriple().getVendor() != llvm::Triple::Apple;
break;
}
if (enable)
jit_loader_sp = std::make_shared<JITLoaderGDB>(process);
return jit_loader_sp;
}
const char *JITLoaderGDB::GetPluginDescriptionStatic() {
return "JIT loader plug-in that watches for JIT events using the GDB "
"interface.";
}
lldb_private::ConstString JITLoaderGDB::GetPluginName() {
return GetPluginNameStatic();
}
uint32_t JITLoaderGDB::GetPluginVersion() { return 1; }
void JITLoaderGDB::Initialize() {
PluginManager::RegisterPlugin(GetPluginNameStatic(),
GetPluginDescriptionStatic(), CreateInstance,
DebuggerInitialize);
}
void JITLoaderGDB::Terminate() {
PluginManager::UnregisterPlugin(CreateInstance);
}
bool JITLoaderGDB::DidSetJITBreakpoint() const {
return LLDB_BREAK_ID_IS_VALID(m_jit_break_id);
}
addr_t JITLoaderGDB::GetSymbolAddress(ModuleList &module_list,
ConstString name,
SymbolType symbol_type) const {
SymbolContextList target_symbols;
Target &target = m_process->GetTarget();
module_list.FindSymbolsWithNameAndType(name, symbol_type, target_symbols);
if (target_symbols.IsEmpty())
return LLDB_INVALID_ADDRESS;
SymbolContext sym_ctx;
target_symbols.GetContextAtIndex(0, sym_ctx);
const Address jit_descriptor_addr = sym_ctx.symbol->GetAddress();
if (!jit_descriptor_addr.IsValid())
return LLDB_INVALID_ADDRESS;
const addr_t jit_addr = jit_descriptor_addr.GetLoadAddress(&target);
return jit_addr;
}