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Diffstat (limited to 'lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp')
| -rw-r--r-- | lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp new file mode 100644 index 0000000000000..ce168f0210471 --- /dev/null +++ b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp @@ -0,0 +1,269 @@ +//===-- UnwindAssembly-x86.cpp ----------------------------------*- C++ -*-===// +// +// 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 "UnwindAssembly-x86.h" +#include "x86AssemblyInspectionEngine.h" + +#include "llvm-c/Disassembler.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/Support/TargetSelect.h" + +#include "lldb/Core/Address.h" +#include "lldb/Core/PluginManager.h" +#include "lldb/Symbol/UnwindPlan.h" +#include "lldb/Target/ABI.h" +#include "lldb/Target/ExecutionContext.h" +#include "lldb/Target/Process.h" +#include "lldb/Target/RegisterContext.h" +#include "lldb/Target/RegisterNumber.h" +#include "lldb/Target/Target.h" +#include "lldb/Target/Thread.h" +#include "lldb/Target/UnwindAssembly.h" +#include "lldb/Utility/ArchSpec.h" +#include "lldb/Utility/Status.h" + +using namespace lldb; +using namespace lldb_private; + +// UnwindAssemblyParser_x86 method definitions + +UnwindAssembly_x86::UnwindAssembly_x86(const ArchSpec &arch) + : lldb_private::UnwindAssembly(arch), + m_assembly_inspection_engine(new x86AssemblyInspectionEngine(arch)) {} + +UnwindAssembly_x86::~UnwindAssembly_x86() { + delete m_assembly_inspection_engine; +} + +bool UnwindAssembly_x86::GetNonCallSiteUnwindPlanFromAssembly( + AddressRange &func, Thread &thread, UnwindPlan &unwind_plan) { + if (!func.GetBaseAddress().IsValid() || func.GetByteSize() == 0) + return false; + if (m_assembly_inspection_engine == nullptr) + return false; + ProcessSP process_sp(thread.GetProcess()); + if (process_sp.get() == nullptr) + return false; + const bool prefer_file_cache = true; + std::vector<uint8_t> function_text(func.GetByteSize()); + Status error; + if (process_sp->GetTarget().ReadMemory( + func.GetBaseAddress(), prefer_file_cache, function_text.data(), + func.GetByteSize(), error) == func.GetByteSize()) { + RegisterContextSP reg_ctx(thread.GetRegisterContext()); + m_assembly_inspection_engine->Initialize(reg_ctx); + return m_assembly_inspection_engine->GetNonCallSiteUnwindPlanFromAssembly( + function_text.data(), func.GetByteSize(), func, unwind_plan); + } + return false; +} + +bool UnwindAssembly_x86::AugmentUnwindPlanFromCallSite( + AddressRange &func, Thread &thread, UnwindPlan &unwind_plan) { + bool do_augment_unwindplan = true; + + UnwindPlan::RowSP first_row = unwind_plan.GetRowForFunctionOffset(0); + UnwindPlan::RowSP last_row = unwind_plan.GetRowForFunctionOffset(-1); + + int wordsize = 8; + ProcessSP process_sp(thread.GetProcess()); + if (process_sp.get() == nullptr) + return false; + + wordsize = process_sp->GetTarget().GetArchitecture().GetAddressByteSize(); + + RegisterNumber sp_regnum(thread, eRegisterKindGeneric, + LLDB_REGNUM_GENERIC_SP); + RegisterNumber pc_regnum(thread, eRegisterKindGeneric, + LLDB_REGNUM_GENERIC_PC); + + // Does this UnwindPlan describe the prologue? I want to see that the CFA is + // set in terms of the stack pointer plus an offset, and I want to see that + // rip is retrieved at the CFA-wordsize. If there is no description of the + // prologue, don't try to augment this eh_frame unwinder code, fall back to + // assembly parsing instead. + + if (first_row->GetCFAValue().GetValueType() != + UnwindPlan::Row::FAValue::isRegisterPlusOffset || + RegisterNumber(thread, unwind_plan.GetRegisterKind(), + first_row->GetCFAValue().GetRegisterNumber()) != + sp_regnum || + first_row->GetCFAValue().GetOffset() != wordsize) { + return false; + } + UnwindPlan::Row::RegisterLocation first_row_pc_loc; + if (!first_row->GetRegisterInfo( + pc_regnum.GetAsKind(unwind_plan.GetRegisterKind()), + first_row_pc_loc) || + !first_row_pc_loc.IsAtCFAPlusOffset() || + first_row_pc_loc.GetOffset() != -wordsize) { + return false; + } + + // It looks like the prologue is described. Is the epilogue described? If it + // is, no need to do any augmentation. + + if (first_row != last_row && + first_row->GetOffset() != last_row->GetOffset()) { + // The first & last row have the same CFA register and the same CFA offset + // value and the CFA register is esp/rsp (the stack pointer). + + // We're checking that both of them have an unwind rule like "CFA=esp+4" or + // CFA+rsp+8". + + if (first_row->GetCFAValue().GetValueType() == + last_row->GetCFAValue().GetValueType() && + first_row->GetCFAValue().GetRegisterNumber() == + last_row->GetCFAValue().GetRegisterNumber() && + first_row->GetCFAValue().GetOffset() == + last_row->GetCFAValue().GetOffset()) { + // Get the register locations for eip/rip from the first & last rows. Are + // they both CFA plus an offset? Is it the same offset? + + UnwindPlan::Row::RegisterLocation last_row_pc_loc; + if (last_row->GetRegisterInfo( + pc_regnum.GetAsKind(unwind_plan.GetRegisterKind()), + last_row_pc_loc)) { + if (last_row_pc_loc.IsAtCFAPlusOffset() && + first_row_pc_loc.GetOffset() == last_row_pc_loc.GetOffset()) { + + // One last sanity check: Is the unwind rule for getting the caller + // pc value "deref the CFA-4" or "deref the CFA-8"? + + // If so, we have an UnwindPlan that already describes the epilogue + // and we don't need to modify it at all. + + if (first_row_pc_loc.GetOffset() == -wordsize) { + do_augment_unwindplan = false; + } + } + } + } + } + + if (do_augment_unwindplan) { + if (!func.GetBaseAddress().IsValid() || func.GetByteSize() == 0) + return false; + if (m_assembly_inspection_engine == nullptr) + return false; + const bool prefer_file_cache = true; + std::vector<uint8_t> function_text(func.GetByteSize()); + Status error; + if (process_sp->GetTarget().ReadMemory( + func.GetBaseAddress(), prefer_file_cache, function_text.data(), + func.GetByteSize(), error) == func.GetByteSize()) { + RegisterContextSP reg_ctx(thread.GetRegisterContext()); + m_assembly_inspection_engine->Initialize(reg_ctx); + return m_assembly_inspection_engine->AugmentUnwindPlanFromCallSite( + function_text.data(), func.GetByteSize(), func, unwind_plan, reg_ctx); + } + } + + return false; +} + +bool UnwindAssembly_x86::GetFastUnwindPlan(AddressRange &func, Thread &thread, + UnwindPlan &unwind_plan) { + // if prologue is + // 55 pushl %ebp + // 89 e5 movl %esp, %ebp + // or + // 55 pushq %rbp + // 48 89 e5 movq %rsp, %rbp + + // We should pull in the ABI architecture default unwind plan and return that + + llvm::SmallVector<uint8_t, 4> opcode_data; + + ProcessSP process_sp = thread.GetProcess(); + if (process_sp) { + Target &target(process_sp->GetTarget()); + const bool prefer_file_cache = true; + Status error; + if (target.ReadMemory(func.GetBaseAddress(), prefer_file_cache, + opcode_data.data(), 4, error) == 4) { + uint8_t i386_push_mov[] = {0x55, 0x89, 0xe5}; + uint8_t x86_64_push_mov[] = {0x55, 0x48, 0x89, 0xe5}; + + if (memcmp(opcode_data.data(), i386_push_mov, sizeof(i386_push_mov)) == + 0 || + memcmp(opcode_data.data(), x86_64_push_mov, + sizeof(x86_64_push_mov)) == 0) { + ABISP abi_sp = process_sp->GetABI(); + if (abi_sp) { + return abi_sp->CreateDefaultUnwindPlan(unwind_plan); + } + } + } + } + return false; +} + +bool UnwindAssembly_x86::FirstNonPrologueInsn( + AddressRange &func, const ExecutionContext &exe_ctx, + Address &first_non_prologue_insn) { + + if (!func.GetBaseAddress().IsValid()) + return false; + + Target *target = exe_ctx.GetTargetPtr(); + if (target == nullptr) + return false; + + if (m_assembly_inspection_engine == nullptr) + return false; + + const bool prefer_file_cache = true; + std::vector<uint8_t> function_text(func.GetByteSize()); + Status error; + if (target->ReadMemory(func.GetBaseAddress(), prefer_file_cache, + function_text.data(), func.GetByteSize(), + error) == func.GetByteSize()) { + size_t offset; + if (m_assembly_inspection_engine->FindFirstNonPrologueInstruction( + function_text.data(), func.GetByteSize(), offset)) { + first_non_prologue_insn = func.GetBaseAddress(); + first_non_prologue_insn.Slide(offset); + } + return true; + } + return false; +} + +UnwindAssembly *UnwindAssembly_x86::CreateInstance(const ArchSpec &arch) { + const llvm::Triple::ArchType cpu = arch.GetMachine(); + if (cpu == llvm::Triple::x86 || cpu == llvm::Triple::x86_64) + return new UnwindAssembly_x86(arch); + return nullptr; +} + +// PluginInterface protocol in UnwindAssemblyParser_x86 + +ConstString UnwindAssembly_x86::GetPluginName() { + return GetPluginNameStatic(); +} + +uint32_t UnwindAssembly_x86::GetPluginVersion() { return 1; } + +void UnwindAssembly_x86::Initialize() { + PluginManager::RegisterPlugin(GetPluginNameStatic(), + GetPluginDescriptionStatic(), CreateInstance); +} + +void UnwindAssembly_x86::Terminate() { + PluginManager::UnregisterPlugin(CreateInstance); +} + +lldb_private::ConstString UnwindAssembly_x86::GetPluginNameStatic() { + static ConstString g_name("x86"); + return g_name; +} + +const char *UnwindAssembly_x86::GetPluginDescriptionStatic() { + return "i386 and x86_64 assembly language profiler plugin."; +} |