ABIMacOSX_i386.h revision 360784 
1//===-- ABIMacOSX_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_ABIMacOSX_i386_h_
10#define liblldb_ABIMacOSX_i386_h_
11
12#include "lldb/Core/Value.h"
13#include "lldb/Target/ABI.h"
14#include "lldb/lldb-private.h"
15
16class ABIMacOSX_i386 : public lldb_private::ABI {
17public:
18  ~ABIMacOSX_i386() override = default;
19
20  size_t GetRedZoneSize() const override;
21
22  bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,
23                          lldb::addr_t func_addr, lldb::addr_t return_addr,
24                          llvm::ArrayRef<lldb::addr_t> args) const override;
25
26  bool GetArgumentValues(lldb_private::Thread &thread,
27                         lldb_private::ValueList &values) const override;
28
29  lldb_private::Status
30  SetReturnValueObject(lldb::StackFrameSP &frame_sp,
31                       lldb::ValueObjectSP &new_value) override;
32
33  bool
34  CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
35
36  bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
37
38  bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;
39
40  // The Darwin i386 ABI requires that stack frames be 16 byte aligned.
41  // When there is a trap handler on the stack, e.g. _sigtramp in userland
42  // code, we've seen that the stack pointer is often not aligned properly
43  // before the handler is invoked.  This means that lldb will stop the unwind
44  // early -- before the function which caused the trap.
45  //
46  // To work around this, we relax that alignment to be just word-size
47  // (4-bytes).
48  // Whitelisting the trap handlers for user space would be easy (_sigtramp) but
49  // in other environments there can be a large number of different functions
50  // involved in async traps.
51  //
52  // If we were to enforce 16-byte alignment, we also need to relax to 4-byte
53  // alignment for non-darwin i386 targets.
54  bool CallFrameAddressIsValid(lldb::addr_t cfa) override {
55    // Make sure the stack call frame addresses are are 4 byte aligned
56    if (cfa & (4ull - 1ull))
57      return false; // Not 4 byte aligned
58    if (cfa == 0)
59      return false; // Zero is not a valid stack address
60    return true;
61  }
62
63  bool CodeAddressIsValid(lldb::addr_t pc) override {
64    // Just make sure the address is a valid 32 bit address.
65    return pc <= UINT32_MAX;
66  }
67
68  const lldb_private::RegisterInfo *
69  GetRegisterInfoArray(uint32_t &count) override;
70
71  // Static Functions
72
73  static void Initialize();
74
75  static void Terminate();
76
77  static lldb::ABISP CreateInstance(lldb::ProcessSP process_sp, const lldb_private::ArchSpec &arch);
78
79  // PluginInterface protocol
80
81  static lldb_private::ConstString GetPluginNameStatic();
82
83  lldb_private::ConstString GetPluginName() override;
84
85  uint32_t GetPluginVersion() override;
86
87protected:
88  lldb::ValueObjectSP
89  GetReturnValueObjectImpl(lldb_private::Thread &thread,
90                           lldb_private::CompilerType &ast_type) const override;
91
92  bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info);
93
94private:
95  ABIMacOSX_i386(lldb::ProcessSP process_sp,
96                 std::unique_ptr<llvm::MCRegisterInfo> info_up)
97      : lldb_private::ABI(std::move(process_sp), std::move(info_up)) {
98    // Call CreateInstance instead.
99  }
100};
101
102#endif // liblldb_ABIMacOSX_i386_h_
103