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llvm-project/lldb/source/Symbol/FuncUnwinders.cpp

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//===-- FuncUnwinders.cpp ----------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Symbol/FuncUnwinders.h"
#include "lldb/Core/Address.h"
#include "lldb/Core/AddressRange.h"
#include "lldb/Symbol/ArmUnwindInfo.h"
#include "lldb/Symbol/CompactUnwindInfo.h"
#include "lldb/Symbol/DWARFCallFrameInfo.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/UnwindPlan.h"
#include "lldb/Symbol/UnwindTable.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterNumber.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/UnwindAssembly.h"
using namespace lldb;
using namespace lldb_private;
//------------------------------------------------
/// constructor
//------------------------------------------------
FuncUnwinders::FuncUnwinders(UnwindTable &unwind_table, AddressRange range)
: m_unwind_table(unwind_table), m_range(range), m_mutex(),
m_unwind_plan_assembly_sp(), m_unwind_plan_eh_frame_sp(),
m_unwind_plan_eh_frame_augmented_sp(), m_unwind_plan_compact_unwind(),
m_unwind_plan_arm_unwind_sp(), m_unwind_plan_fast_sp(),
m_unwind_plan_arch_default_sp(),
m_unwind_plan_arch_default_at_func_entry_sp(),
m_tried_unwind_plan_assembly(false), m_tried_unwind_plan_eh_frame(false),
m_tried_unwind_plan_eh_frame_augmented(false),
m_tried_unwind_plan_compact_unwind(false),
m_tried_unwind_plan_arm_unwind(false), m_tried_unwind_fast(false),
m_tried_unwind_arch_default(false),
m_tried_unwind_arch_default_at_func_entry(false),
m_first_non_prologue_insn() {}
//------------------------------------------------
/// destructor
//------------------------------------------------
FuncUnwinders::~FuncUnwinders() {}
UnwindPlanSP FuncUnwinders::GetUnwindPlanAtCallSite(Target &target,
int current_offset) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
UnwindPlanSP unwind_plan_sp = GetEHFrameUnwindPlan(target, current_offset);
if (unwind_plan_sp)
return unwind_plan_sp;
unwind_plan_sp = GetCompactUnwindUnwindPlan(target, current_offset);
if (unwind_plan_sp)
return unwind_plan_sp;
unwind_plan_sp = GetArmUnwindUnwindPlan(target, current_offset);
if (unwind_plan_sp)
return unwind_plan_sp;
return nullptr;
}
UnwindPlanSP FuncUnwinders::GetCompactUnwindUnwindPlan(Target &target,
int current_offset) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_compact_unwind.size() > 0)
return m_unwind_plan_compact_unwind[0]; // FIXME support multiple compact
// unwind plans for one func
if (m_tried_unwind_plan_compact_unwind)
return UnwindPlanSP();
m_tried_unwind_plan_compact_unwind = true;
if (m_range.GetBaseAddress().IsValid()) {
Address current_pc(m_range.GetBaseAddress());
if (current_offset != -1)
current_pc.SetOffset(current_pc.GetOffset() + current_offset);
CompactUnwindInfo *compact_unwind = m_unwind_table.GetCompactUnwindInfo();
if (compact_unwind) {
UnwindPlanSP unwind_plan_sp(new UnwindPlan(lldb::eRegisterKindGeneric));
if (compact_unwind->GetUnwindPlan(target, current_pc, *unwind_plan_sp)) {
m_unwind_plan_compact_unwind.push_back(unwind_plan_sp);
return m_unwind_plan_compact_unwind[0]; // FIXME support multiple
// compact unwind plans for one
// func
}
}
}
return UnwindPlanSP();
}
UnwindPlanSP FuncUnwinders::GetEHFrameUnwindPlan(Target &target,
int current_offset) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_eh_frame_sp.get() || m_tried_unwind_plan_eh_frame)
return m_unwind_plan_eh_frame_sp;
m_tried_unwind_plan_eh_frame = true;
if (m_range.GetBaseAddress().IsValid()) {
Address current_pc(m_range.GetBaseAddress());
if (current_offset != -1)
current_pc.SetOffset(current_pc.GetOffset() + current_offset);
DWARFCallFrameInfo *eh_frame = m_unwind_table.GetEHFrameInfo();
if (eh_frame) {
m_unwind_plan_eh_frame_sp.reset(
new UnwindPlan(lldb::eRegisterKindGeneric));
if (!eh_frame->GetUnwindPlan(current_pc, *m_unwind_plan_eh_frame_sp))
m_unwind_plan_eh_frame_sp.reset();
}
}
return m_unwind_plan_eh_frame_sp;
}
UnwindPlanSP FuncUnwinders::GetArmUnwindUnwindPlan(Target &target,
int current_offset) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_arm_unwind_sp.get() || m_tried_unwind_plan_arm_unwind)
return m_unwind_plan_arm_unwind_sp;
m_tried_unwind_plan_arm_unwind = true;
if (m_range.GetBaseAddress().IsValid()) {
Address current_pc(m_range.GetBaseAddress());
if (current_offset != -1)
current_pc.SetOffset(current_pc.GetOffset() + current_offset);
ArmUnwindInfo *arm_unwind_info = m_unwind_table.GetArmUnwindInfo();
if (arm_unwind_info) {
m_unwind_plan_arm_unwind_sp.reset(
new UnwindPlan(lldb::eRegisterKindGeneric));
if (!arm_unwind_info->GetUnwindPlan(target, current_pc,
*m_unwind_plan_arm_unwind_sp))
m_unwind_plan_arm_unwind_sp.reset();
}
}
return m_unwind_plan_arm_unwind_sp;
}
UnwindPlanSP FuncUnwinders::GetEHFrameAugmentedUnwindPlan(Target &target,
Thread &thread,
int current_offset) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_eh_frame_augmented_sp.get() ||
m_tried_unwind_plan_eh_frame_augmented)
return m_unwind_plan_eh_frame_augmented_sp;
// Only supported on x86 architectures where we get eh_frame from the compiler
// that describes
// the prologue instructions perfectly, and sometimes the epilogue
// instructions too.
if (target.GetArchitecture().GetCore() != ArchSpec::eCore_x86_32_i386 &&
target.GetArchitecture().GetCore() != ArchSpec::eCore_x86_64_x86_64 &&
target.GetArchitecture().GetCore() != ArchSpec::eCore_x86_64_x86_64h) {
m_tried_unwind_plan_eh_frame_augmented = true;
return m_unwind_plan_eh_frame_augmented_sp;
}
m_tried_unwind_plan_eh_frame_augmented = true;
UnwindPlanSP eh_frame_plan = GetEHFrameUnwindPlan(target, current_offset);
if (!eh_frame_plan)
return m_unwind_plan_eh_frame_augmented_sp;
m_unwind_plan_eh_frame_augmented_sp.reset(new UnwindPlan(*eh_frame_plan));
// Augment the eh_frame instructions with epilogue descriptions if necessary
// so the
// UnwindPlan can be used at any instruction in the function.
UnwindAssemblySP assembly_profiler_sp(GetUnwindAssemblyProfiler(target));
if (assembly_profiler_sp) {
if (!assembly_profiler_sp->AugmentUnwindPlanFromCallSite(
m_range, thread, *m_unwind_plan_eh_frame_augmented_sp)) {
m_unwind_plan_eh_frame_augmented_sp.reset();
}
} else {
m_unwind_plan_eh_frame_augmented_sp.reset();
}
return m_unwind_plan_eh_frame_augmented_sp;
}
UnwindPlanSP FuncUnwinders::GetAssemblyUnwindPlan(Target &target,
Thread &thread,
int current_offset) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_assembly_sp.get() || m_tried_unwind_plan_assembly ||
m_unwind_table.GetAllowAssemblyEmulationUnwindPlans() == false) {
return m_unwind_plan_assembly_sp;
}
m_tried_unwind_plan_assembly = true;
UnwindAssemblySP assembly_profiler_sp(GetUnwindAssemblyProfiler(target));
if (assembly_profiler_sp) {
m_unwind_plan_assembly_sp.reset(new UnwindPlan(lldb::eRegisterKindGeneric));
if (!assembly_profiler_sp->GetNonCallSiteUnwindPlanFromAssembly(
m_range, thread, *m_unwind_plan_assembly_sp)) {
m_unwind_plan_assembly_sp.reset();
}
}
return m_unwind_plan_assembly_sp;
}
// This method compares the pc unwind rule in the first row of two UnwindPlans.
// If they have the same way of getting the pc value (e.g. "CFA - 8" + "CFA is
// sp"),
// then it will return LazyBoolTrue.
LazyBool FuncUnwinders::CompareUnwindPlansForIdenticalInitialPCLocation(
Thread &thread, const UnwindPlanSP &a, const UnwindPlanSP &b) {
LazyBool plans_are_identical = eLazyBoolCalculate;
RegisterNumber pc_reg(thread, eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
uint32_t pc_reg_lldb_regnum = pc_reg.GetAsKind(eRegisterKindLLDB);
if (a.get() && b.get()) {
UnwindPlan::RowSP a_first_row = a->GetRowAtIndex(0);
UnwindPlan::RowSP b_first_row = b->GetRowAtIndex(0);
if (a_first_row.get() && b_first_row.get()) {
UnwindPlan::Row::RegisterLocation a_pc_regloc;
UnwindPlan::Row::RegisterLocation b_pc_regloc;
a_first_row->GetRegisterInfo(pc_reg_lldb_regnum, a_pc_regloc);
b_first_row->GetRegisterInfo(pc_reg_lldb_regnum, b_pc_regloc);
plans_are_identical = eLazyBoolYes;
if (a_first_row->GetCFAValue() != b_first_row->GetCFAValue()) {
plans_are_identical = eLazyBoolNo;
}
if (a_pc_regloc != b_pc_regloc) {
plans_are_identical = eLazyBoolNo;
}
}
}
return plans_are_identical;
}
UnwindPlanSP FuncUnwinders::GetUnwindPlanAtNonCallSite(Target &target,
Thread &thread,
int current_offset) {
UnwindPlanSP eh_frame_sp = GetEHFrameUnwindPlan(target, current_offset);
UnwindPlanSP arch_default_at_entry_sp =
GetUnwindPlanArchitectureDefaultAtFunctionEntry(thread);
UnwindPlanSP arch_default_sp = GetUnwindPlanArchitectureDefault(thread);
UnwindPlanSP assembly_sp =
GetAssemblyUnwindPlan(target, thread, current_offset);
// This point of this code is to detect when a function is using a
// non-standard ABI, and the eh_frame
// correctly describes that alternate ABI. This is addressing a specific
// situation on x86_64 linux
// systems where one function in a library pushes a value on the stack and
// jumps to another function.
// So using an assembly instruction based unwind will not work when you're in
// the second function -
// the stack has been modified in a non-ABI way. But we have eh_frame that
// correctly describes how to
// unwind from this location. So we're looking to see if the initial pc
// register save location from
// the eh_frame is different from the assembly unwind, the arch default
// unwind, and the arch default at
// initial function entry.
//
// We may have eh_frame that describes the entire function -- or we may have
// eh_frame that only describes
// the unwind after the prologue has executed -- so we need to check both the
// arch default (once the prologue
// has executed) and the arch default at initial function entry. And we may
// be running on a target where
// we have only some of the assembly/arch default unwind plans available.
if (CompareUnwindPlansForIdenticalInitialPCLocation(
thread, eh_frame_sp, arch_default_at_entry_sp) == eLazyBoolNo &&
CompareUnwindPlansForIdenticalInitialPCLocation(
thread, eh_frame_sp, arch_default_sp) == eLazyBoolNo &&
CompareUnwindPlansForIdenticalInitialPCLocation(
thread, assembly_sp, arch_default_sp) == eLazyBoolNo) {
return eh_frame_sp;
}
UnwindPlanSP eh_frame_augmented_sp =
GetEHFrameAugmentedUnwindPlan(target, thread, current_offset);
if (eh_frame_augmented_sp) {
return eh_frame_augmented_sp;
}
return assembly_sp;
}
UnwindPlanSP FuncUnwinders::GetUnwindPlanFastUnwind(Target &target,
Thread &thread) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_fast_sp.get() || m_tried_unwind_fast)
return m_unwind_plan_fast_sp;
m_tried_unwind_fast = true;
UnwindAssemblySP assembly_profiler_sp(GetUnwindAssemblyProfiler(target));
if (assembly_profiler_sp) {
m_unwind_plan_fast_sp.reset(new UnwindPlan(lldb::eRegisterKindGeneric));
if (!assembly_profiler_sp->GetFastUnwindPlan(m_range, thread,
*m_unwind_plan_fast_sp)) {
m_unwind_plan_fast_sp.reset();
}
}
return m_unwind_plan_fast_sp;
}
UnwindPlanSP FuncUnwinders::GetUnwindPlanArchitectureDefault(Thread &thread) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_arch_default_sp.get() || m_tried_unwind_arch_default)
return m_unwind_plan_arch_default_sp;
m_tried_unwind_arch_default = true;
Address current_pc;
ProcessSP process_sp(thread.CalculateProcess());
if (process_sp) {
ABI *abi = process_sp->GetABI().get();
if (abi) {
m_unwind_plan_arch_default_sp.reset(
new UnwindPlan(lldb::eRegisterKindGeneric));
if (!abi->CreateDefaultUnwindPlan(*m_unwind_plan_arch_default_sp)) {
m_unwind_plan_arch_default_sp.reset();
}
}
}
return m_unwind_plan_arch_default_sp;
}
UnwindPlanSP
FuncUnwinders::GetUnwindPlanArchitectureDefaultAtFunctionEntry(Thread &thread) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_unwind_plan_arch_default_at_func_entry_sp.get() ||
m_tried_unwind_arch_default_at_func_entry)
return m_unwind_plan_arch_default_at_func_entry_sp;
m_tried_unwind_arch_default_at_func_entry = true;
Address current_pc;
ProcessSP process_sp(thread.CalculateProcess());
if (process_sp) {
ABI *abi = process_sp->GetABI().get();
if (abi) {
m_unwind_plan_arch_default_at_func_entry_sp.reset(
new UnwindPlan(lldb::eRegisterKindGeneric));
if (!abi->CreateFunctionEntryUnwindPlan(
*m_unwind_plan_arch_default_at_func_entry_sp)) {
m_unwind_plan_arch_default_at_func_entry_sp.reset();
}
}
}
return m_unwind_plan_arch_default_at_func_entry_sp;
}
Address &FuncUnwinders::GetFirstNonPrologueInsn(Target &target) {
std::lock_guard<std::recursive_mutex> guard(m_mutex);
if (m_first_non_prologue_insn.IsValid())
return m_first_non_prologue_insn;
ExecutionContext exe_ctx(target.shared_from_this(), false);
UnwindAssemblySP assembly_profiler_sp(GetUnwindAssemblyProfiler(target));
if (assembly_profiler_sp)
assembly_profiler_sp->FirstNonPrologueInsn(m_range, exe_ctx,
m_first_non_prologue_insn);
return m_first_non_prologue_insn;
}
const Address &FuncUnwinders::GetFunctionStartAddress() const {
return m_range.GetBaseAddress();
}
lldb::UnwindAssemblySP
FuncUnwinders::GetUnwindAssemblyProfiler(Target &target) {
UnwindAssemblySP assembly_profiler_sp;
ArchSpec arch;
if (m_unwind_table.GetArchitecture(arch)) {
arch.MergeFrom(target.GetArchitecture());
assembly_profiler_sp = UnwindAssembly::FindPlugin(arch);
}
return assembly_profiler_sp;
}
Address FuncUnwinders::GetLSDAAddress(Target &target) {
Address lsda_addr;
UnwindPlanSP unwind_plan_sp = GetEHFrameUnwindPlan(target, -1);
if (unwind_plan_sp.get() == nullptr) {
unwind_plan_sp = GetCompactUnwindUnwindPlan(target, -1);
}
if (unwind_plan_sp.get() && unwind_plan_sp->GetLSDAAddress().IsValid()) {
lsda_addr = unwind_plan_sp->GetLSDAAddress();
}
return lsda_addr;
}
Address FuncUnwinders::GetPersonalityRoutinePtrAddress(Target &target) {
Address personality_addr;
UnwindPlanSP unwind_plan_sp = GetEHFrameUnwindPlan(target, -1);
if (unwind_plan_sp.get() == nullptr) {
unwind_plan_sp = GetCompactUnwindUnwindPlan(target, -1);
}
if (unwind_plan_sp.get() &&
unwind_plan_sp->GetPersonalityFunctionPtr().IsValid()) {
personality_addr = unwind_plan_sp->GetPersonalityFunctionPtr();
}
return personality_addr;
}
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