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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/Core/AddressRange.h"
#include "lldb/Core/Address.h"
#include "lldb/Symbol/FuncUnwinders.h"
#include "lldb/Symbol/ArmUnwindInfo.h"
#include "lldb/Symbol/DWARFCallFrameInfo.h"
#include "lldb/Symbol/CompactUnwindInfo.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/Thread.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/UnwindAssembly.h"
#include "lldb/Utility/RegisterNumber.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)
{
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();
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
if (m_unwind_plan_eh_frame_sp.get() || m_tried_unwind_plan_eh_frame)
return m_unwind_plan_eh_frame_sp;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
if (m_unwind_plan_arm_unwind_sp.get() || m_tried_unwind_plan_arm_unwind)
return m_unwind_plan_arm_unwind_sp;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
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;
}
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
if (m_unwind_plan_assembly_sp.get()
|| m_tried_unwind_plan_assembly
|| m_unwind_table.GetAllowAssemblyEmulationUnwindPlans () == false)
{
return m_unwind_plan_assembly_sp;
}
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
if (m_unwind_plan_fast_sp.get() || m_tried_unwind_fast)
return m_unwind_plan_fast_sp;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
if (m_unwind_plan_arch_default_sp.get() || m_tried_unwind_arch_default)
return m_unwind_plan_arch_default_sp;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
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;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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)
{
if (m_first_non_prologue_insn.IsValid())
return m_first_non_prologue_insn;
std::lock_guard<std::recursive_mutex> guard(m_mutex);
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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