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//===-- UnwindTable.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 "lldb/Symbol/UnwindTable.h"
#include <stdio.h>
#include "lldb/Core/Module.h"
#include "lldb/Core/Section.h"
#include "lldb/Symbol/ArmUnwindInfo.h"
#include "lldb/Symbol/CallFrameInfo.h"
#include "lldb/Symbol/CompactUnwindInfo.h"
#include "lldb/Symbol/DWARFCallFrameInfo.h"
#include "lldb/Symbol/FuncUnwinders.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/SymbolVendor.h"
// There is one UnwindTable object per ObjectFile. It contains a list of Unwind
// objects -- one per function, populated lazily -- for the ObjectFile. Each
// Unwind object has multiple UnwindPlans for different scenarios.
using namespace lldb;
using namespace lldb_private;
UnwindTable::UnwindTable(Module &module)
: m_module(module), m_unwinds(), m_initialized(false), m_mutex(),
m_object_file_unwind_up(), m_eh_frame_up(), m_compact_unwind_up(),
m_arm_unwind_up() {}
// We can't do some of this initialization when the ObjectFile is running its
// ctor; delay doing it until needed for something.
void UnwindTable::Initialize() {
if (m_initialized)
return;
std::lock_guard<std::mutex> guard(m_mutex);
if (m_initialized) // check again once we've acquired the lock
return;
m_initialized = true;
ObjectFile *object_file = m_module.GetObjectFile();
if (!object_file)
return;
m_object_file_unwind_up = object_file->CreateCallFrameInfo();
SectionList *sl = m_module.GetSectionList();
if (!sl)
return;
SectionSP sect = sl->FindSectionByType(eSectionTypeEHFrame, true);
if (sect.get()) {
m_eh_frame_up = std::make_unique<DWARFCallFrameInfo>(
*object_file, sect, DWARFCallFrameInfo::EH);
}
sect = sl->FindSectionByType(eSectionTypeDWARFDebugFrame, true);
if (sect) {
m_debug_frame_up = std::make_unique<DWARFCallFrameInfo>(
*object_file, sect, DWARFCallFrameInfo::DWARF);
}
sect = sl->FindSectionByType(eSectionTypeCompactUnwind, true);
if (sect) {
m_compact_unwind_up =
std::make_unique<CompactUnwindInfo>(*object_file, sect);
}
sect = sl->FindSectionByType(eSectionTypeARMexidx, true);
if (sect) {
SectionSP sect_extab = sl->FindSectionByType(eSectionTypeARMextab, true);
if (sect_extab.get()) {
m_arm_unwind_up =
std::make_unique<ArmUnwindInfo>(*object_file, sect, sect_extab);
}
}
}
UnwindTable::~UnwindTable() {}
llvm::Optional<AddressRange> UnwindTable::GetAddressRange(const Address &addr,
SymbolContext &sc) {
AddressRange range;
// First check the unwind info from the object file plugin
if (m_object_file_unwind_up &&
m_object_file_unwind_up->GetAddressRange(addr, range))
return range;
// Check the symbol context
if (sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0,
false, range) &&
range.GetBaseAddress().IsValid())
return range;
// Does the eh_frame unwind info has a function bounds for this addr?
if (m_eh_frame_up && m_eh_frame_up->GetAddressRange(addr, range))
return range;
// Try debug_frame as well
if (m_debug_frame_up && m_debug_frame_up->GetAddressRange(addr, range))
return range;
return llvm::None;
}
FuncUnwindersSP
UnwindTable::GetFuncUnwindersContainingAddress(const Address &addr,
SymbolContext &sc) {
Initialize();
std::lock_guard<std::mutex> guard(m_mutex);
// There is an UnwindTable per object file, so we can safely use file handles
addr_t file_addr = addr.GetFileAddress();
iterator end = m_unwinds.end();
iterator insert_pos = end;
if (!m_unwinds.empty()) {
insert_pos = m_unwinds.lower_bound(file_addr);
iterator pos = insert_pos;
if ((pos == m_unwinds.end()) ||
(pos != m_unwinds.begin() &&
pos->second->GetFunctionStartAddress() != addr))
--pos;
if (pos->second->ContainsAddress(addr))
return pos->second;
}
auto range_or = GetAddressRange(addr, sc);
if (!range_or)
return nullptr;
FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, *range_or));
m_unwinds.insert(insert_pos,
std::make_pair(range_or->GetBaseAddress().GetFileAddress(),
func_unwinder_sp));
return func_unwinder_sp;
}
// Ignore any existing FuncUnwinders for this function, create a new one and
// don't add it to the UnwindTable. This is intended for use by target modules
// show-unwind where we want to create new UnwindPlans, not re-use existing
// ones.
FuncUnwindersSP
UnwindTable::GetUncachedFuncUnwindersContainingAddress(const Address &addr,
SymbolContext &sc) {
Initialize();
auto range_or = GetAddressRange(addr, sc);
if (!range_or)
return nullptr;
return std::make_shared<FuncUnwinders>(*this, *range_or);
}
void UnwindTable::Dump(Stream &s) {
std::lock_guard<std::mutex> guard(m_mutex);
s.Format("UnwindTable for '{0}':\n", m_module.GetFileSpec());
const_iterator begin = m_unwinds.begin();
const_iterator end = m_unwinds.end();
for (const_iterator pos = begin; pos != end; ++pos) {
s.Printf("[%u] 0x%16.16" PRIx64 "\n", (unsigned)std::distance(begin, pos),
pos->first);
}
s.EOL();
}
lldb_private::CallFrameInfo *UnwindTable::GetObjectFileUnwindInfo() {
Initialize();
return m_object_file_unwind_up.get();
}
DWARFCallFrameInfo *UnwindTable::GetEHFrameInfo() {
Initialize();
return m_eh_frame_up.get();
}
DWARFCallFrameInfo *UnwindTable::GetDebugFrameInfo() {
Initialize();
return m_debug_frame_up.get();
}
CompactUnwindInfo *UnwindTable::GetCompactUnwindInfo() {
Initialize();
return m_compact_unwind_up.get();
}
ArmUnwindInfo *UnwindTable::GetArmUnwindInfo() {
Initialize();
return m_arm_unwind_up.get();
}
SymbolFile *UnwindTable::GetSymbolFile() { return m_module.GetSymbolFile(); }
ArchSpec UnwindTable::GetArchitecture() { return m_module.GetArchitecture(); }
bool UnwindTable::GetAllowAssemblyEmulationUnwindPlans() {
if (ObjectFile *object_file = m_module.GetObjectFile())
return object_file->AllowAssemblyEmulationUnwindPlans();
return false;
}
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