ABISysV_i386.h revision 360784 
1//===------------------- ABISysV_i386.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 liblldb_ABISysV_i386_h_
10#define liblldb_ABISysV_i386_h_
11
12#include "lldb/Target/ABI.h"
13#include "lldb/lldb-private.h"
14
15class ABISysV_i386 : public lldb_private::ABI {
16public:
17  ~ABISysV_i386() override = default;
18
19  size_t GetRedZoneSize() const override {
20    return 0; // There is no red zone for i386 Architecture
21  }
22
23  bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,
24                          lldb::addr_t functionAddress,
25                          lldb::addr_t returnAddress,
26                          llvm::ArrayRef<lldb::addr_t> args) const override;
27
28  bool GetArgumentValues(lldb_private::Thread &thread,
29                         lldb_private::ValueList &values) const override;
30
31  lldb_private::Status
32  SetReturnValueObject(lldb::StackFrameSP &frame_sp,
33                       lldb::ValueObjectSP &new_value) override;
34
35  lldb::ValueObjectSP
36  GetReturnValueObjectImpl(lldb_private::Thread &thread,
37                           lldb_private::CompilerType &type) const override;
38
39  bool
40  CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
41
42  bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
43
44  bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override {
45    return !RegisterIsCalleeSaved(reg_info);
46  }
47
48  // The SysV i386 ABI requires that stack frames be 16 byte aligned.
49  // When there is a trap handler on the stack, e.g. _sigtramp in userland
50  // code, we've seen that the stack pointer is often not aligned properly
51  // before the handler is invoked.  This means that lldb will stop the unwind
52  // early -- before the function which caused the trap.
53  //
54  // To work around this, we relax that alignment to be just word-size
55  // (4-bytes).
56  // Whitelisting the trap handlers for user space would be easy (_sigtramp) but
57  // in other environments there can be a large number of different functions
58  // involved in async traps.
59
60  // ToDo: When __m256 arguments are passed then stack frames should be
61  // 32 byte aligned. Decide what to do for 32 byte alignment checking
62  bool CallFrameAddressIsValid(lldb::addr_t cfa) override {
63    // Make sure the stack call frame addresses are 4 byte aligned
64    if (cfa & (4ull - 1ull))
65      return false; // Not 4 byte aligned
66    if (cfa == 0)
67      return false; // Zero is not a valid stack address
68    return true;
69  }
70
71  bool CodeAddressIsValid(lldb::addr_t pc) override {
72    // Check whether the address is a valid 32 bit address
73    return (pc <= UINT32_MAX);
74  }
75
76  const lldb_private::RegisterInfo *
77  GetRegisterInfoArray(uint32_t &count) override;
78
79  // Static Functions
80
81  static void Initialize();
82
83  static void Terminate();
84
85  static lldb::ABISP CreateInstance(lldb::ProcessSP process_sp, const lldb_private::ArchSpec &arch);
86
87  // PluginInterface protocol
88
89  static lldb_private::ConstString GetPluginNameStatic();
90
91  lldb_private::ConstString GetPluginName() override;
92
93  uint32_t GetPluginVersion() override { return 1; }
94
95protected:
96  lldb::ValueObjectSP
97  GetReturnValueObjectSimple(lldb_private::Thread &thread,
98                             lldb_private::CompilerType &ast_type) const;
99
100  bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info);
101
102private:
103  ABISysV_i386(lldb::ProcessSP process_sp,
104               std::unique_ptr<llvm::MCRegisterInfo> info_up)
105      : lldb_private::ABI(std::move(process_sp), std::move(info_up)) {
106    // Call CreateInstance instead.
107  }
108};
109
110#endif // liblldb_ABISysV_i386_h_
111