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 LLDB_SOURCE_PLUGINS_ABI_X86_ABIMACOSX_I386_H
10 #define LLDB_SOURCE_PLUGINS_ABI_X86_ABIMACOSX_I386_H
11 
12 #include "Plugins/ABI/X86/ABIX86_i386.h"
13 #include "lldb/Core/Value.h"
14 #include "lldb/lldb-private.h"
15 
16 class ABIMacOSX_i386 : public ABIX86_i386 {
17 public:
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   // Allowing 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.
CallFrameAddressIsValid(lldb::addr_t cfa)54   bool CallFrameAddressIsValid(lldb::addr_t cfa) override {
55     // Make sure the stack call frame addresses 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 
CodeAddressIsValid(lldb::addr_t pc)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   // Static Functions
69 
70   static void Initialize();
71 
72   static void Terminate();
73 
74   static lldb::ABISP CreateInstance(lldb::ProcessSP process_sp, const lldb_private::ArchSpec &arch);
75 
76   // PluginInterface protocol
77 
GetPluginNameStatic()78   static llvm::StringRef GetPluginNameStatic() { return "abi.macosx-i386"; }
79 
GetPluginName()80   llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
81 
82 protected:
83   lldb::ValueObjectSP
84   GetReturnValueObjectImpl(lldb_private::Thread &thread,
85                            lldb_private::CompilerType &ast_type) const override;
86 
87   bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info);
88 
GetMCName(std::string name)89   std::string GetMCName(std::string name) override {
90     MapRegisterName(name, "stmm", "st");
91     return name;
92   }
93 
94 private:
95   using ABIX86_i386::ABIX86_i386; // Call CreateInstance instead.
96 };
97 
98 #endif // LLDB_SOURCE_PLUGINS_ABI_X86_ABIMACOSX_I386_H
99