1 //===-- x86AssemblyInspectionEngine.h ---------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLDB_SOURCE_PLUGINS_UNWINDASSEMBLY_X86_X86ASSEMBLYINSPECTIONENGINE_H
10 #define LLDB_SOURCE_PLUGINS_UNWINDASSEMBLY_X86_X86ASSEMBLYINSPECTIONENGINE_H
11 
12 #include "llvm-c/Disassembler.h"
13 
14 #include "lldb/Utility/ArchSpec.h"
15 #include "lldb/Utility/ConstString.h"
16 #include "lldb/lldb-enumerations.h"
17 #include "lldb/lldb-forward.h"
18 #include "lldb/lldb-private.h"
19 
20 #include <map>
21 #include <vector>
22 
23 namespace lldb_private {
24 
25 // x86AssemblyInspectionEngine - a class which will take a buffer of bytes
26 // of i386/x86_64 instructions and create an UnwindPlan based on those
27 // assembly instructions.
28 class x86AssemblyInspectionEngine {
29 
30 public:
31   /// default ctor
32   x86AssemblyInspectionEngine(const lldb_private::ArchSpec &arch);
33 
34   /// default dtor
35   ~x86AssemblyInspectionEngine();
36 
37   /// One of the two initialize methods that can be called on this object;
38   /// they must be called before any of the assembly inspection methods
39   /// are called.  This one should be used if the caller has access to a
40   /// valid RegisterContext.
41   void Initialize(lldb::RegisterContextSP &reg_ctx);
42 
43   /// One of the two initialize methods that can be called on this object;
44   /// they must be called before any of the assembly inspection methods
45   /// are called.  This one takes a vector of register name and lldb
46   /// register numbers.
47   struct lldb_reg_info {
48     const char *name = nullptr;
49     uint32_t lldb_regnum = LLDB_INVALID_REGNUM;
50     lldb_reg_info() = default;
51   };
52   void Initialize(std::vector<lldb_reg_info> &reg_info);
53 
54   /// Create an UnwindPlan for a "non-call site" stack frame situation.
55   /// This is usually when this function/method is currently executing, and may
56   /// be at
57   /// a location where exception-handling style unwind information (eh_frame,
58   /// compact unwind info, arm unwind info)
59   /// are not valid.
60   /// \p data is a pointer to the instructions for the function
61   /// \p size is the size of the instruction buffer above
62   /// \p func_range is the start Address and size of the function, to be
63   /// included in the UnwindPlan
64   /// \p unwind_plan is the unwind plan that this method creates
65   /// \returns true if it was able to create an UnwindPlan; false if not.
66   bool
67   GetNonCallSiteUnwindPlanFromAssembly(uint8_t *data, size_t size,
68                                        lldb_private::AddressRange &func_range,
69                                        lldb_private::UnwindPlan &unwind_plan);
70 
71   /// Take an existing UnwindPlan, probably from eh_frame which may be missing
72   /// description
73   /// of the epilogue instructions, and add the epilogue description to it based
74   /// on the
75   /// instructions in the function.
76   ///
77   /// The \p unwind_plan 's register numbers must be converted into the lldb
78   /// register numbering
79   /// scheme OR a RegisterContext must be provided in \p reg_ctx.  If the \p
80   /// unwind_plan
81   /// register numbers are already in lldb register numbering, \p reg_ctx may be
82   /// null.
83   /// \returns true if the \p unwind_plan was updated, false if it was not.
84   bool AugmentUnwindPlanFromCallSite(uint8_t *data, size_t size,
85                                      lldb_private::AddressRange &func_range,
86                                      lldb_private::UnwindPlan &unwind_plan,
87                                      lldb::RegisterContextSP &reg_ctx);
88 
89   bool FindFirstNonPrologueInstruction(uint8_t *data, size_t size,
90                                        size_t &offset);
91 
92 private:
93   bool nonvolatile_reg_p(int machine_regno);
94   bool push_rbp_pattern_p();
95   bool push_0_pattern_p();
96   bool push_imm_pattern_p();
97   bool push_extended_pattern_p();
98   bool push_misc_reg_p();
99   bool mov_rsp_rbp_pattern_p();
100   bool mov_rsp_rbx_pattern_p();
101   bool mov_rbp_rsp_pattern_p();
102   bool mov_rbx_rsp_pattern_p();
103   bool sub_rsp_pattern_p(int &amount);
104   bool add_rsp_pattern_p(int &amount);
105   bool lea_rsp_pattern_p(int &amount);
106   bool lea_rbp_rsp_pattern_p(int &amount);
107   bool lea_rbx_rsp_pattern_p(int &amount);
108   bool and_rsp_pattern_p();
109   bool push_reg_p(int &regno);
110   bool pop_reg_p(int &regno);
111   bool pop_rbp_pattern_p();
112   bool pop_misc_reg_p();
113   bool leave_pattern_p();
114   bool call_next_insn_pattern_p();
115   bool mov_reg_to_local_stack_frame_p(int &regno, int &rbp_offset);
116   bool ret_pattern_p();
117   bool retguard_prologue_p(size_t offset, int insn_len);
118   bool jmp_to_reg_p();
119   bool pc_rel_branch_or_jump_p (const int instruction_length, int &offset);
120   bool non_local_branch_p (const lldb::addr_t current_func_text_offset,
121                            const lldb_private::AddressRange &func_range,
122                            const int instruction_length);
123   bool local_branch_p (const lldb::addr_t current_func_text_offset,
124                        const lldb_private::AddressRange &func_range,
125                        const int instruction_length,
126                        lldb::addr_t &target_insn_offset);
127   uint16_t extract_2(uint8_t *b);
128   int16_t extract_2_signed(uint8_t *b);
129   uint32_t extract_4(uint8_t *b);
130   int32_t extract_4_signed(uint8_t *b);
131 
132   bool instruction_length(uint8_t *insn, int &length, uint32_t buffer_remaining_bytes);
133 
134   bool machine_regno_to_lldb_regno(int machine_regno, uint32_t &lldb_regno);
135 
136   enum CPU { k_i386, k_x86_64, k_cpu_unspecified };
137 
138   enum i386_register_numbers {
139     k_machine_eax = 0,
140     k_machine_ecx = 1,
141     k_machine_edx = 2,
142     k_machine_ebx = 3,
143     k_machine_esp = 4,
144     k_machine_ebp = 5,
145     k_machine_esi = 6,
146     k_machine_edi = 7,
147     k_machine_eip = 8
148   };
149 
150   enum x86_64_register_numbers {
151     k_machine_rax = 0,
152     k_machine_rcx = 1,
153     k_machine_rdx = 2,
154     k_machine_rbx = 3,
155     k_machine_rsp = 4,
156     k_machine_rbp = 5,
157     k_machine_rsi = 6,
158     k_machine_rdi = 7,
159     k_machine_r8 = 8,
160     k_machine_r9 = 9,
161     k_machine_r10 = 10,
162     k_machine_r11 = 11,
163     k_machine_r12 = 12,
164     k_machine_r13 = 13,
165     k_machine_r14 = 14,
166     k_machine_r15 = 15,
167     k_machine_rip = 16
168   };
169 
170   enum { kMaxInstructionByteSize = 32 };
171 
172   uint8_t *m_cur_insn;
173 
174   uint32_t m_machine_ip_regnum;
175   uint32_t m_machine_sp_regnum;
176   uint32_t m_machine_fp_regnum;
177   uint32_t m_machine_alt_fp_regnum;
178   uint32_t m_lldb_ip_regnum;
179   uint32_t m_lldb_sp_regnum;
180   uint32_t m_lldb_fp_regnum;
181   uint32_t m_lldb_alt_fp_regnum;
182 
183   typedef std::map<uint32_t, lldb_reg_info> MachineRegnumToNameAndLLDBRegnum;
184 
185   MachineRegnumToNameAndLLDBRegnum m_reg_map;
186 
187   lldb_private::ArchSpec m_arch;
188   CPU m_cpu;
189   int m_wordsize;
190 
191   bool m_register_map_initialized;
192 
193   ::LLVMDisasmContextRef m_disasm_context;
194 
195   x86AssemblyInspectionEngine(const x86AssemblyInspectionEngine &) = delete;
196   const x86AssemblyInspectionEngine &
197   operator=(const x86AssemblyInspectionEngine &) = delete;
198 };
199 
200 } // namespace lldb_private
201 
202 #endif // LLDB_SOURCE_PLUGINS_UNWINDASSEMBLY_X86_X86ASSEMBLYINSPECTIONENGINE_H
203