xref: /freebsd-src/contrib/llvm-project/lldb/source/Plugins/ABI/X86/ABISysV_i386.h (revision 349cc55c9796c4596a5b9904cd3281af295f878f)

//===------------------- ABISysV_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_ABISYSV_I386_H
#define LLDB_SOURCE_PLUGINS_ABI_X86_ABISYSV_I386_H

#include "Plugins/ABI/X86/ABIX86_i386.h"
#include "lldb/lldb-private.h"

class ABISysV_i386 : public ABIX86_i386 {
public:
  ~ABISysV_i386() override = default;

  size_t GetRedZoneSize() const override {
    return 0; // There is no red zone for i386 Architecture
  }

  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 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;

  lldb::ValueObjectSP
  GetReturnValueObjectImpl(lldb_private::Thread &thread,
                           lldb_private::CompilerType &type) const 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 {
    return !RegisterIsCalleeSaved(reg_info);
  }

  // The SysV 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).
  // Allowing 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.

  // ToDo: When __m256 arguments are passed then stack frames should be
  // 32 byte aligned. Decide what to do for 32 byte alignment checking
  bool CallFrameAddressIsValid(lldb::addr_t cfa) override {
    // Make sure the stack call frame addresses 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 {
    // Check whether the address is a valid 32 bit address
    return (pc <= UINT32_MAX);
  }

  // Static Functions

  static void Initialize();

  static void Terminate();

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

  // PluginInterface protocol

  static llvm::StringRef GetPluginNameStatic() { return "sysv-i386"; }

  llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }

protected:
  lldb::ValueObjectSP
  GetReturnValueObjectSimple(lldb_private::Thread &thread,
                             lldb_private::CompilerType &ast_type) const;

  bool RegisterIsCalleeSaved(const lldb_private::RegisterInfo *reg_info);

private:
  using ABIX86_i386::ABIX86_i386; // Call CreateInstance instead.
};

#endif // LLDB_SOURCE_PLUGINS_ABI_X86_ABISYSV_I386_H