1 //===-- UnwindAssembly-x86.cpp ----------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "UnwindAssembly-x86.h"
11 #include "x86AssemblyInspectionEngine.h"
13 #include "llvm-c/Disassembler.h"
14 #include "llvm/ADT/STLExtras.h"
15 #include "llvm/Support/TargetSelect.h"
17 #include "lldb/Core/Address.h"
18 #include "lldb/Core/ArchSpec.h"
19 #include "lldb/Core/PluginManager.h"
20 #include "lldb/Symbol/UnwindPlan.h"
21 #include "lldb/Target/ABI.h"
22 #include "lldb/Target/ExecutionContext.h"
23 #include "lldb/Target/Process.h"
24 #include "lldb/Target/RegisterContext.h"
25 #include "lldb/Target/RegisterNumber.h"
26 #include "lldb/Target/Target.h"
27 #include "lldb/Target/Thread.h"
28 #include "lldb/Target/UnwindAssembly.h"
29 #include "lldb/Utility/Status.h"
32 using namespace lldb_private;
34 //-----------------------------------------------------------------------------------------------
35 // UnwindAssemblyParser_x86 method definitions
36 //-----------------------------------------------------------------------------------------------
38 UnwindAssembly_x86::UnwindAssembly_x86(const ArchSpec &arch)
39 : lldb_private::UnwindAssembly(arch),
40 m_assembly_inspection_engine(new x86AssemblyInspectionEngine(arch)) {}
42 UnwindAssembly_x86::~UnwindAssembly_x86() {
43 delete m_assembly_inspection_engine;
46 bool UnwindAssembly_x86::GetNonCallSiteUnwindPlanFromAssembly(
47 AddressRange &func, Thread &thread, UnwindPlan &unwind_plan) {
48 if (!func.GetBaseAddress().IsValid() || func.GetByteSize() == 0)
50 if (m_assembly_inspection_engine == nullptr)
52 ProcessSP process_sp(thread.GetProcess());
53 if (process_sp.get() == nullptr)
55 const bool prefer_file_cache = true;
56 std::vector<uint8_t> function_text(func.GetByteSize());
58 if (process_sp->GetTarget().ReadMemory(
59 func.GetBaseAddress(), prefer_file_cache, function_text.data(),
60 func.GetByteSize(), error) == func.GetByteSize()) {
61 RegisterContextSP reg_ctx(thread.GetRegisterContext());
62 m_assembly_inspection_engine->Initialize(reg_ctx);
63 return m_assembly_inspection_engine->GetNonCallSiteUnwindPlanFromAssembly(
64 function_text.data(), func.GetByteSize(), func, unwind_plan);
69 bool UnwindAssembly_x86::AugmentUnwindPlanFromCallSite(
70 AddressRange &func, Thread &thread, UnwindPlan &unwind_plan) {
71 bool do_augment_unwindplan = true;
73 UnwindPlan::RowSP first_row = unwind_plan.GetRowForFunctionOffset(0);
74 UnwindPlan::RowSP last_row = unwind_plan.GetRowForFunctionOffset(-1);
77 ProcessSP process_sp(thread.GetProcess());
78 if (process_sp.get() == nullptr)
81 wordsize = process_sp->GetTarget().GetArchitecture().GetAddressByteSize();
83 RegisterNumber sp_regnum(thread, eRegisterKindGeneric,
84 LLDB_REGNUM_GENERIC_SP);
85 RegisterNumber pc_regnum(thread, eRegisterKindGeneric,
86 LLDB_REGNUM_GENERIC_PC);
88 // Does this UnwindPlan describe the prologue? I want to see that the CFA is
90 // in terms of the stack pointer plus an offset, and I want to see that rip is
91 // retrieved at the CFA-wordsize.
92 // If there is no description of the prologue, don't try to augment this
94 // unwinder code, fall back to assembly parsing instead.
96 if (first_row->GetCFAValue().GetValueType() !=
97 UnwindPlan::Row::CFAValue::isRegisterPlusOffset ||
98 RegisterNumber(thread, unwind_plan.GetRegisterKind(),
99 first_row->GetCFAValue().GetRegisterNumber()) !=
101 first_row->GetCFAValue().GetOffset() != wordsize) {
104 UnwindPlan::Row::RegisterLocation first_row_pc_loc;
105 if (first_row->GetRegisterInfo(
106 pc_regnum.GetAsKind(unwind_plan.GetRegisterKind()),
107 first_row_pc_loc) == false ||
108 first_row_pc_loc.IsAtCFAPlusOffset() == false ||
109 first_row_pc_loc.GetOffset() != -wordsize) {
113 // It looks like the prologue is described.
114 // Is the epilogue described? If it is, no need to do any augmentation.
116 if (first_row != last_row &&
117 first_row->GetOffset() != last_row->GetOffset()) {
118 // The first & last row have the same CFA register
119 // and the same CFA offset value
120 // and the CFA register is esp/rsp (the stack pointer).
122 // We're checking that both of them have an unwind rule like "CFA=esp+4" or
125 if (first_row->GetCFAValue().GetValueType() ==
126 last_row->GetCFAValue().GetValueType() &&
127 first_row->GetCFAValue().GetRegisterNumber() ==
128 last_row->GetCFAValue().GetRegisterNumber() &&
129 first_row->GetCFAValue().GetOffset() ==
130 last_row->GetCFAValue().GetOffset()) {
131 // Get the register locations for eip/rip from the first & last rows.
132 // Are they both CFA plus an offset? Is it the same offset?
134 UnwindPlan::Row::RegisterLocation last_row_pc_loc;
135 if (last_row->GetRegisterInfo(
136 pc_regnum.GetAsKind(unwind_plan.GetRegisterKind()),
138 if (last_row_pc_loc.IsAtCFAPlusOffset() &&
139 first_row_pc_loc.GetOffset() == last_row_pc_loc.GetOffset()) {
141 // One last sanity check: Is the unwind rule for getting the caller
143 // "deref the CFA-4" or "deref the CFA-8"?
145 // If so, we have an UnwindPlan that already describes the epilogue
147 // to modify it at all.
149 if (first_row_pc_loc.GetOffset() == -wordsize) {
150 do_augment_unwindplan = false;
157 if (do_augment_unwindplan) {
158 if (!func.GetBaseAddress().IsValid() || func.GetByteSize() == 0)
160 if (m_assembly_inspection_engine == nullptr)
162 const bool prefer_file_cache = true;
163 std::vector<uint8_t> function_text(func.GetByteSize());
165 if (process_sp->GetTarget().ReadMemory(
166 func.GetBaseAddress(), prefer_file_cache, function_text.data(),
167 func.GetByteSize(), error) == func.GetByteSize()) {
168 RegisterContextSP reg_ctx(thread.GetRegisterContext());
169 m_assembly_inspection_engine->Initialize(reg_ctx);
170 return m_assembly_inspection_engine->AugmentUnwindPlanFromCallSite(
171 function_text.data(), func.GetByteSize(), func, unwind_plan, reg_ctx);
178 bool UnwindAssembly_x86::GetFastUnwindPlan(AddressRange &func, Thread &thread,
179 UnwindPlan &unwind_plan) {
182 // 89 e5 movl %esp, %ebp
185 // 48 89 e5 movq %rsp, %rbp
187 // We should pull in the ABI architecture default unwind plan and return that
189 llvm::SmallVector<uint8_t, 4> opcode_data;
191 ProcessSP process_sp = thread.GetProcess();
193 Target &target(process_sp->GetTarget());
194 const bool prefer_file_cache = true;
196 if (target.ReadMemory(func.GetBaseAddress(), prefer_file_cache,
197 opcode_data.data(), 4, error) == 4) {
198 uint8_t i386_push_mov[] = {0x55, 0x89, 0xe5};
199 uint8_t x86_64_push_mov[] = {0x55, 0x48, 0x89, 0xe5};
201 if (memcmp(opcode_data.data(), i386_push_mov, sizeof(i386_push_mov)) ==
203 memcmp(opcode_data.data(), x86_64_push_mov,
204 sizeof(x86_64_push_mov)) == 0) {
205 ABISP abi_sp = process_sp->GetABI();
207 return abi_sp->CreateDefaultUnwindPlan(unwind_plan);
215 bool UnwindAssembly_x86::FirstNonPrologueInsn(
216 AddressRange &func, const ExecutionContext &exe_ctx,
217 Address &first_non_prologue_insn) {
219 if (!func.GetBaseAddress().IsValid())
222 Target *target = exe_ctx.GetTargetPtr();
223 if (target == nullptr)
226 if (m_assembly_inspection_engine == nullptr)
229 const bool prefer_file_cache = true;
230 std::vector<uint8_t> function_text(func.GetByteSize());
232 if (target->ReadMemory(func.GetBaseAddress(), prefer_file_cache,
233 function_text.data(), func.GetByteSize(),
234 error) == func.GetByteSize()) {
236 if (m_assembly_inspection_engine->FindFirstNonPrologueInstruction(
237 function_text.data(), func.GetByteSize(), offset)) {
238 first_non_prologue_insn = func.GetBaseAddress();
239 first_non_prologue_insn.Slide(offset);
246 UnwindAssembly *UnwindAssembly_x86::CreateInstance(const ArchSpec &arch) {
247 const llvm::Triple::ArchType cpu = arch.GetMachine();
248 if (cpu == llvm::Triple::x86 || cpu == llvm::Triple::x86_64)
249 return new UnwindAssembly_x86(arch);
253 //------------------------------------------------------------------
254 // PluginInterface protocol in UnwindAssemblyParser_x86
255 //------------------------------------------------------------------
257 ConstString UnwindAssembly_x86::GetPluginName() {
258 return GetPluginNameStatic();
261 uint32_t UnwindAssembly_x86::GetPluginVersion() { return 1; }
263 void UnwindAssembly_x86::Initialize() {
264 PluginManager::RegisterPlugin(GetPluginNameStatic(),
265 GetPluginDescriptionStatic(), CreateInstance);
268 void UnwindAssembly_x86::Terminate() {
269 PluginManager::UnregisterPlugin(CreateInstance);
272 lldb_private::ConstString UnwindAssembly_x86::GetPluginNameStatic() {
273 static ConstString g_name("x86");
277 const char *UnwindAssembly_x86::GetPluginDescriptionStatic() {
278 return "i386 and x86_64 assembly language profiler plugin.";