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

source code of lldb/include/lldb/Target/ABI.h