//===-- ABI.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_TARGET_ABI_H

#define LLDB_TARGET_ABI_H

#include "lldb/Core/PluginInterface.h"

#include "lldb/Symbol/UnwindPlan.h"

#include "lldb/Target/DynamicRegisterInfo.h"

#include "lldb/Utility/Status.h"

#include "lldb/lldb-private.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/MC/MCRegisterInfo.h"

namespace llvm {

class Type;

}

namespace lldb_private {

class ABI : public PluginInterface {

public:

  struct CallArgument {

    enum eType {

      HostPointer = 0, /* pointer to host data */

      TargetValue,     /* value is on the target or literal */

    };

    eType type;  /* value of eType */

    size_t size; /* size in bytes of this argument */

    lldb::addr_t value;                 /* literal value */

    std::unique_ptr<uint8_t[]> data_up; /* host data pointer */

  };

  ~ABI() override;

  virtual size_t GetRedZoneSize() const = 0;

  virtual bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,

                                  lldb::addr_t functionAddress,

                                  lldb::addr_t returnAddress,

                                  llvm::ArrayRef<lldb::addr_t> args) const = 0;

  // Prepare trivial call used from ThreadPlanFunctionCallUsingABI

  // AD:

  //  . Because i don't want to change other ABI's this is not declared pure

  //  virtual.

  //    The dummy implementation will simply fail.  Only HexagonABI will

  //    currently

  //    use this method.

  //  . Two PrepareTrivialCall's is not good design so perhaps this should be

  //  combined.

  //

  virtual bool PrepareTrivialCall(lldb_private::Thread &thread, lldb::addr_t sp,

                                  lldb::addr_t functionAddress,

                                  lldb::addr_t returnAddress,

                                  llvm::Type &prototype,

                                  llvm::ArrayRef<CallArgument> args) const;

  virtual bool GetArgumentValues(Thread &thread, ValueList &values) const = 0;

  lldb::ValueObjectSP GetReturnValueObject(Thread &thread, CompilerType &type,

                                           bool persistent = true) const;

  // specialized to work with llvm IR types

  lldb::ValueObjectSP GetReturnValueObject(Thread &thread, llvm::Type &type,

                                           bool persistent = true) const;

  // Set the Return value object in the current frame as though a function with

  virtual Status SetReturnValueObject(lldb::StackFrameSP &frame_sp,

                                      lldb::ValueObjectSP &new_value) = 0;

protected:

  // This is the method the ABI will call to actually calculate the return

  // value. Don't put it in a persistent value object, that will be done by the

  // ABI::GetReturnValueObject.

  virtual lldb::ValueObjectSP

  GetReturnValueObjectImpl(Thread &thread, CompilerType &ast_type) const = 0;

  // specialized to work with llvm IR types

  virtual lldb::ValueObjectSP

  GetReturnValueObjectImpl(Thread &thread, llvm::Type &ir_type) const;

  /// Request to get a Process shared pointer.

  ///

  /// This ABI object may not have been created with a Process object,

  /// or the Process object may no longer be alive.  Be sure to handle

  /// the case where the shared pointer returned does not have an

  /// object inside it.

  lldb::ProcessSP GetProcessSP() const { return m_process_wp.lock(); }

public:

  virtual bool CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) = 0;

  virtual bool CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) = 0;

  virtual bool RegisterIsVolatile(const RegisterInfo *reg_info) = 0;

  virtual bool

  GetFallbackRegisterLocation(const RegisterInfo *reg_info,

                              UnwindPlan::Row::RegisterLocation &unwind_regloc);

  // Should take a look at a call frame address (CFA) which is just the stack

  // pointer value upon entry to a function. ABIs usually impose alignment

  // restrictions (4, 8 or 16 byte aligned), and zero is usually not allowed.

  // This function should return true if "cfa" is valid call frame address for

  // the ABI, and false otherwise. This is used by the generic stack frame

  // unwinding code to help determine when a stack ends.

  virtual bool CallFrameAddressIsValid(lldb::addr_t cfa) = 0;

  // Validates a possible PC value and returns true if an opcode can be at

  // "pc".

  virtual bool CodeAddressIsValid(lldb::addr_t pc) = 0;

  /// Some targets might use bits in a code address to indicate a mode switch.

  /// ARM uses bit zero to signify a code address is thumb, so any ARM ABI

  /// plug-ins would strip those bits.

  /// @{

  virtual lldb::addr_t FixCodeAddress(lldb::addr_t pc) { return pc; }

  virtual lldb::addr_t FixDataAddress(lldb::addr_t pc) { return pc; }

  /// @}

  /// Use this method when you do not know, or do not care what kind of address

  /// you are fixing. On platforms where there would be a difference between the

  /// two types, it will pick the safest option.

  ///

  /// Its purpose is to signal that no specific choice was made and provide an

  /// alternative to randomly picking FixCode/FixData address. Which could break

  /// platforms where there is a difference (only Arm Thumb at this time).

  virtual lldb::addr_t FixAnyAddress(lldb::addr_t pc) {

    // On Arm Thumb fixing a code address zeroes the bottom bit, so FixData is

    // the safe choice. On any other platform (so far) code and data addresses

    // are fixed in the same way.

    return FixDataAddress(pc);

  }

  llvm::MCRegisterInfo &GetMCRegisterInfo() { return *m_mc_register_info_up; }

  virtual void

  AugmentRegisterInfo(std::vector<DynamicRegisterInfo::Register> &regs) = 0;

  virtual bool GetPointerReturnRegister(const char *&name) { return false; }

  virtual uint64_t GetStackFrameSize() { return 512 * 1024; }

  static lldb::ABISP FindPlugin(lldb::ProcessSP process_sp, const ArchSpec &arch);

protected:

  ABI(lldb::ProcessSP process_sp, std::unique_ptr<llvm::MCRegisterInfo> info_up)

      : m_process_wp(process_sp), m_mc_register_info_up(std::move(info_up)) {

    assert(m_mc_register_info_up && "ABI must have MCRegisterInfo");

  }

  /// Utility function to construct a MCRegisterInfo using the ArchSpec triple.

  /// Plugins wishing to customize the construction can construct the

  /// MCRegisterInfo themselves.

  static std::unique_ptr<llvm::MCRegisterInfo>

  MakeMCRegisterInfo(const ArchSpec &arch);

  lldb::ProcessWP m_process_wp;

  std::unique_ptr<llvm::MCRegisterInfo> m_mc_register_info_up;

  virtual lldb::addr_t FixCodeAddress(lldb::addr_t pc, lldb::addr_t mask) {

    return pc;

  }

private:

  ABI(const ABI &) = delete;

  const ABI &operator=(const ABI &) = delete;

};

class RegInfoBasedABI : public ABI {

public:

  void AugmentRegisterInfo(

      std::vector<DynamicRegisterInfo::Register> &regs) override;

protected:

  using ABI::ABI;

  bool GetRegisterInfoByName(llvm::StringRef name, RegisterInfo &info);

  virtual const RegisterInfo *GetRegisterInfoArray(uint32_t &count) = 0;

};

class MCBasedABI : public ABI {

public:

  void AugmentRegisterInfo(

      std::vector<DynamicRegisterInfo::Register> &regs) override;

  /// If the register name is of the form "<from_prefix>[<number>]" then change

  /// the name to "<to_prefix>[<number>]". Otherwise, leave the name unchanged.

  static void MapRegisterName(std::string &reg, llvm::StringRef from_prefix,

                              llvm::StringRef to_prefix);

protected:

  using ABI::ABI;

  /// Return eh_frame and dwarf numbers for the given register.

  virtual std::pair<uint32_t, uint32_t> GetEHAndDWARFNums(llvm::StringRef reg);

  /// Return the generic number of the given register.

  virtual uint32_t GetGenericNum(llvm::StringRef reg) = 0;

  /// For the given (capitalized) lldb register name, return the name of this

  /// register in the MCRegisterInfo struct.

  virtual std::string GetMCName(std::string reg) { return reg; }

};

} // namespace lldb_private

#endif // LLDB_TARGET_ABI_H