text: //===-- ABIMacOSX_i386.h ----------------------------------------*- C++ -*-===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLDB_SOURCE_PLUGINS_ABI_X86_ABIMACOSX_I386_H
  #define LLDB_SOURCE_PLUGINS_ABI_X86_ABIMACOSX_I386_H
  
  #include "lldb/Core/Value.h"
  #include "lldb/Target/ABI.h"
  #include "lldb/lldb-private.h"
  
  class ABIMacOSX_i386 : public lldb_private::RegInfoBasedABI {
  public:
    ~ABIMacOSX_i386() override = default;
  
    size_t GetRedZoneSize() const override;
  
    bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,
                            lldb::addr_t func_addr, lldb::addr_t return_addr,
                            llvm::ArrayRef<lldb::addr_t> args) const override;
  
    bool GetArgumentValues(lldb_private::Thread &thread,
                           lldb_private::ValueList &values) const override;
  
    lldb_private::Status
    SetReturnValueObject(lldb::StackFrameSP &frame_sp,
                         lldb::ValueObjectSP &new_value) override;
  
    bool
    CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
  
    bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
  
    bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;
  
    // The Darwin i386 ABI requires that stack frames be 16 byte aligned.
    // When there is a trap handler on the stack, e.g. _sigtramp in userland
    // code, we've seen that the stack pointer is often not aligned properly
    // before the handler is invoked.  This means that lldb will stop the unwind
    // early -- before the function which caused the trap.
    //
    // To work around this, we relax that alignment to be just word-size
    // (4-bytes).
    // Whitelisting the trap handlers for user space would be easy (_sigtramp) but
    // in other environments there can be a large number of different functions
    // involved in async traps.
    //
    // If we were to enforce 16-byte alignment, we also need to relax to 4-byte
    // alignment for non-darwin i386 targets.
    bool CallFrameAddressIsValid(lldb::addr_t cfa) override {
      // Make sure the stack call frame addresses are are 4 byte aligned
      if (cfa & (4ull - 1ull))
        return false; // Not 4 byte aligned
      if (cfa == 0)
        return false; // Zero is not a valid stack address
      return true;
    }
  
    bool CodeAddressIsValid(lldb::addr_t pc) override {
      // Just make sure the address is a valid 32 bit address.
      return pc <= UINT32_MAX;
    }
  
    const lldb_private::RegisterInfo *
    GetRegisterInfoArray(uint32_t &count) override;
  
    // Static Functions
  
    static void Initialize();
  
    static void Terminate();
  
    static lldb::ABISP CreateInstance(lldb::ProcessSP process_sp, const lldb_private::ArchSpec &arch);
  
    // PluginInterface protocol
  
    static lldb_private::ConstString GetPluginNameStatic();
  
    lldb_private::ConstString GetPluginName() override;
  
    uint32_t GetPluginVersion() override;
  
  protected:
    lldb::ValueObjectSP
    GetReturnValueObjectImpl(lldb_private::Thread &thread,
                             lldb_private::CompilerType &ast_type) const override;
  
    bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info);
  
  private:
    using lldb_private::RegInfoBasedABI::RegInfoBasedABI; // Call CreateInstance instead.
  };
  
  #endif // LLDB_SOURCE_PLUGINS_ABI_X86_ABIMACOSX_I386_H
  