1//===-- ABI.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_TARGET_ABI_H
10#define LLDB_TARGET_ABI_H
11
12#include "lldb/Core/PluginInterface.h"
13#include "lldb/Symbol/UnwindPlan.h"
14#include "lldb/Target/DynamicRegisterInfo.h"
15#include "lldb/Utility/Status.h"
16#include "lldb/lldb-private.h"
17
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/MC/MCRegisterInfo.h"
20
21namespace llvm {
22class Type;
23}
24
25namespace lldb_private {
26
27class ABI : public PluginInterface {
28public:
29  struct CallArgument {
30    enum eType {
31      HostPointer = 0, /* pointer to host data */
32      TargetValue,     /* value is on the target or literal */
33    };
34    eType type;  /* value of eType */
35    size_t size; /* size in bytes of this argument */
36
37    lldb::addr_t value;                 /* literal value */
38    std::unique_ptr<uint8_t[]> data_up; /* host data pointer */
39  };
40
41  ~ABI() override;
42
43  virtual size_t GetRedZoneSize() const = 0;
44
45  virtual bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,
46                                  lldb::addr_t functionAddress,
47                                  lldb::addr_t returnAddress,
48                                  llvm::ArrayRef<lldb::addr_t> args) const = 0;
49
50  // Prepare trivial call used from ThreadPlanFunctionCallUsingABI
51  // AD:
52  //  . Because i don't want to change other ABI's this is not declared pure
53  //  virtual.
54  //    The dummy implementation will simply fail.  Only HexagonABI will
55  //    currently
56  //    use this method.
57  //  . Two PrepareTrivialCall's is not good design so perhaps this should be
58  //  combined.
59  //
60  virtual bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,
61                                  lldb::addr_t functionAddress,
62                                  lldb::addr_t returnAddress,
63                                  llvm::Type &prototype,
64                                  llvm::ArrayRef<CallArgument> args) const;
65
66  virtual bool GetArgumentValues(Thread &thread, ValueList &values) const = 0;
67
68  lldb::ValueObjectSP GetReturnValueObject(Thread &thread, CompilerType &type,
69                                           bool persistent = true) const;
70
71  // specialized to work with llvm IR types
72  lldb::ValueObjectSP GetReturnValueObject(Thread &thread, llvm::Type &type,
73                                           bool persistent = true) const;
74
75  // Set the Return value object in the current frame as though a function with
76  virtual Status SetReturnValueObject(lldb::StackFrameSP &frame_sp,
77                                      lldb::ValueObjectSP &new_value) = 0;
78
79protected:
80  // This is the method the ABI will call to actually calculate the return
81  // value. Don't put it in a persistent value object, that will be done by the
82  // ABI::GetReturnValueObject.
83  virtual lldb::ValueObjectSP
84  GetReturnValueObjectImpl(Thread &thread, CompilerType &ast_type) const = 0;
85
86  // specialized to work with llvm IR types
87  virtual lldb::ValueObjectSP
88  GetReturnValueObjectImpl(Thread &thread, llvm::Type &ir_type) const;
89
90  /// Request to get a Process shared pointer.
91  ///
92  /// This ABI object may not have been created with a Process object,
93  /// or the Process object may no longer be alive.  Be sure to handle
94  /// the case where the shared pointer returned does not have an
95  /// object inside it.
96  lldb::ProcessSP GetProcessSP() const { return m_process_wp.lock(); }
97
98public:
99  virtual bool CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) = 0;
100
101  virtual bool CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) = 0;
102
103  virtual bool RegisterIsVolatile(const RegisterInfo *reg_info) = 0;
104
105  virtual bool
106  GetFallbackRegisterLocation(const RegisterInfo *reg_info,
107                              UnwindPlan::Row::RegisterLocation &unwind_regloc);
108
109  // Should take a look at a call frame address (CFA) which is just the stack
110  // pointer value upon entry to a function. ABIs usually impose alignment
111  // restrictions (4, 8 or 16 byte aligned), and zero is usually not allowed.
112  // This function should return true if "cfa" is valid call frame address for
113  // the ABI, and false otherwise. This is used by the generic stack frame
114  // unwinding code to help determine when a stack ends.
115  virtual bool CallFrameAddressIsValid(lldb::addr_t cfa) = 0;
116
117  // Validates a possible PC value and returns true if an opcode can be at
118  // "pc".
119  virtual bool CodeAddressIsValid(lldb::addr_t pc) = 0;
120
121  /// Some targets might use bits in a code address to indicate a mode switch.
122  /// ARM uses bit zero to signify a code address is thumb, so any ARM ABI
123  /// plug-ins would strip those bits.
124  /// @{
125  virtual lldb::addr_t FixCodeAddress(lldb::addr_t pc) { return pc; }
126  virtual lldb::addr_t FixDataAddress(lldb::addr_t pc) { return pc; }
127  /// @}
128
129  /// Use this method when you do not know, or do not care what kind of address
130  /// you are fixing. On platforms where there would be a difference between the
131  /// two types, it will pick the safest option.
132  ///
133  /// Its purpose is to signal that no specific choice was made and provide an
134  /// alternative to randomly picking FixCode/FixData address. Which could break
135  /// platforms where there is a difference (only Arm Thumb at this time).
136  virtual lldb::addr_t FixAnyAddress(lldb::addr_t pc) {
137    // On Arm Thumb fixing a code address zeroes the bottom bit, so FixData is
138    // the safe choice. On any other platform (so far) code and data addresses
139    // are fixed in the same way.
140    return FixDataAddress(pc);
141  }
142
143  llvm::MCRegisterInfo &GetMCRegisterInfo() { return *m_mc_register_info_up; }
144
145  virtual void
146  AugmentRegisterInfo(std::vector<DynamicRegisterInfo::Register> &regs) = 0;
147
148  virtual bool GetPointerReturnRegister(const char *&name) { return false; }
149
150  virtual uint64_t GetStackFrameSize() { return 512 * 1024; }
151
152  static lldb::ABISP FindPlugin(lldb::ProcessSP process_sp, const ArchSpec &arch);
153
154protected:
155  ABI(lldb::ProcessSP process_sp, std::unique_ptr<llvm::MCRegisterInfo> info_up)
156      : m_process_wp(process_sp), m_mc_register_info_up(std::move(info_up)) {
157    assert(m_mc_register_info_up && "ABI must have MCRegisterInfo");
158  }
159
160  /// Utility function to construct a MCRegisterInfo using the ArchSpec triple.
161  /// Plugins wishing to customize the construction can construct the
162  /// MCRegisterInfo themselves.
163  static std::unique_ptr<llvm::MCRegisterInfo>
164  MakeMCRegisterInfo(const ArchSpec &arch);
165
166  lldb::ProcessWP m_process_wp;
167  std::unique_ptr<llvm::MCRegisterInfo> m_mc_register_info_up;
168
169  virtual lldb::addr_t FixCodeAddress(lldb::addr_t pc, lldb::addr_t mask) {
170    return pc;
171  }
172
173private:
174  ABI(const ABI &) = delete;
175  const ABI &operator=(const ABI &) = delete;
176};
177
178class RegInfoBasedABI : public ABI {
179public:
180  void AugmentRegisterInfo(
181      std::vector<DynamicRegisterInfo::Register> &regs) override;
182
183protected:
184  using ABI::ABI;
185
186  bool GetRegisterInfoByName(llvm::StringRef name, RegisterInfo &info);
187
188  virtual const RegisterInfo *GetRegisterInfoArray(uint32_t &count) = 0;
189};
190
191class MCBasedABI : public ABI {
192public:
193  void AugmentRegisterInfo(
194      std::vector<DynamicRegisterInfo::Register> &regs) override;
195
196  /// If the register name is of the form "<from_prefix>[<number>]" then change
197  /// the name to "<to_prefix>[<number>]". Otherwise, leave the name unchanged.
198  static void MapRegisterName(std::string &reg, llvm::StringRef from_prefix,
199                              llvm::StringRef to_prefix);
200
201protected:
202  using ABI::ABI;
203
204  /// Return eh_frame and dwarf numbers for the given register.
205  virtual std::pair<uint32_t, uint32_t> GetEHAndDWARFNums(llvm::StringRef reg);
206
207  /// Return the generic number of the given register.
208  virtual uint32_t GetGenericNum(llvm::StringRef reg) = 0;
209
210  /// For the given (capitalized) lldb register name, return the name of this
211  /// register in the MCRegisterInfo struct.
212  virtual std::string GetMCName(std::string reg) { return reg; }
213};
214
215} // namespace lldb_private
216
217#endif // LLDB_TARGET_ABI_H
218