llvm-project/lldb/source/API/SBInstruction.cpp

//===-- SBInstruction.cpp ---------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/API/SBInstruction.h"

#include "lldb/API/SBAddress.h"
#include "lldb/API/SBFrame.h"
#include "lldb/API/SBInstruction.h"
#include "lldb/API/SBStream.h"
#include "lldb/API/SBTarget.h"

#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/Disassembler.h"
#include "lldb/Core/EmulateInstruction.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/StreamFile.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Target.h"

//----------------------------------------------------------------------
// We recently fixed a leak in one of the Instruction subclasses where
// the instruction will only hold a weak reference to the disassembler
// to avoid a cycle that was keeping both objects alive (leak) and we
// need the InstructionImpl class to make sure our public API behaves
// as users would expect. Calls in our public API allow clients to do
// things like:
//
// 1  lldb::SBInstruction inst;
// 2  inst = target.ReadInstructions(pc, 1).GetInstructionAtIndex(0)
// 3  if (inst.DoesBranch())
// 4  ...
//
// There was a temporary lldb::DisassemblerSP object created in the
// SBInstructionList that was returned by lldb.target.ReadInstructions()
// that will go away after line 2 but the "inst" object should be able
// to still answer questions about itself. So we make sure that any
// SBInstruction objects that are given out have a strong reference to
// the disassembler and the instruction so that the object can live and
// successfully respond to all queries.
//----------------------------------------------------------------------
class InstructionImpl {
public:
  InstructionImpl(const lldb::DisassemblerSP &disasm_sp,
                  const lldb::InstructionSP &inst_sp)
      : m_disasm_sp(disasm_sp), m_inst_sp(inst_sp) {}

  lldb::InstructionSP GetSP() const { return m_inst_sp; }

  bool IsValid() const { return (bool)m_inst_sp; }

protected:
  lldb::DisassemblerSP m_disasm_sp; // Can be empty/invalid
  lldb::InstructionSP m_inst_sp;
};

using namespace lldb;
using namespace lldb_private;

SBInstruction::SBInstruction() : m_opaque_sp() {}

SBInstruction::SBInstruction(const lldb::DisassemblerSP &disasm_sp,
                             const lldb::InstructionSP &inst_sp)
    : m_opaque_sp(new InstructionImpl(disasm_sp, inst_sp)) {}

SBInstruction::SBInstruction(const SBInstruction &rhs)
    : m_opaque_sp(rhs.m_opaque_sp) {}

const SBInstruction &SBInstruction::operator=(const SBInstruction &rhs) {
  if (this != &rhs)
    m_opaque_sp = rhs.m_opaque_sp;
  return *this;
}

SBInstruction::~SBInstruction() {}

bool SBInstruction::IsValid() { return m_opaque_sp && m_opaque_sp->IsValid(); }

SBAddress SBInstruction::GetAddress() {
  SBAddress sb_addr;
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp && inst_sp->GetAddress().IsValid())
    sb_addr.SetAddress(&inst_sp->GetAddress());
  return sb_addr;
}

const char *SBInstruction::GetMnemonic(SBTarget target) {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    ExecutionContext exe_ctx;
    TargetSP target_sp(target.GetSP());
    std::unique_lock<std::recursive_mutex> lock;
    if (target_sp) {
      lock = std::unique_lock<std::recursive_mutex>(target_sp->GetAPIMutex());

      target_sp->CalculateExecutionContext(exe_ctx);
      exe_ctx.SetProcessSP(target_sp->GetProcessSP());
    }
    return inst_sp->GetMnemonic(&exe_ctx);
  }
  return NULL;
}

const char *SBInstruction::GetOperands(SBTarget target) {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    ExecutionContext exe_ctx;
    TargetSP target_sp(target.GetSP());
    std::unique_lock<std::recursive_mutex> lock;
    if (target_sp) {
      lock = std::unique_lock<std::recursive_mutex>(target_sp->GetAPIMutex());

      target_sp->CalculateExecutionContext(exe_ctx);
      exe_ctx.SetProcessSP(target_sp->GetProcessSP());
    }
    return inst_sp->GetOperands(&exe_ctx);
  }
  return NULL;
}

const char *SBInstruction::GetComment(SBTarget target) {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    ExecutionContext exe_ctx;
    TargetSP target_sp(target.GetSP());
    std::unique_lock<std::recursive_mutex> lock;
    if (target_sp) {
      lock = std::unique_lock<std::recursive_mutex>(target_sp->GetAPIMutex());

      target_sp->CalculateExecutionContext(exe_ctx);
      exe_ctx.SetProcessSP(target_sp->GetProcessSP());
    }
    return inst_sp->GetComment(&exe_ctx);
  }
  return NULL;
}

size_t SBInstruction::GetByteSize() {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp)
    return inst_sp->GetOpcode().GetByteSize();
  return 0;
}

SBData SBInstruction::GetData(SBTarget target) {
  lldb::SBData sb_data;
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    DataExtractorSP data_extractor_sp(new DataExtractor());
    if (inst_sp->GetData(*data_extractor_sp)) {
      sb_data.SetOpaque(data_extractor_sp);
    }
  }
  return sb_data;
}

bool SBInstruction::DoesBranch() {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp)
    return inst_sp->DoesBranch();
  return false;
}

bool SBInstruction::HasDelaySlot() {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp)
    return inst_sp->HasDelaySlot();
  return false;
}

lldb::InstructionSP SBInstruction::GetOpaque() {
  if (m_opaque_sp)
    return m_opaque_sp->GetSP();
  else
    return lldb::InstructionSP();
}

void SBInstruction::SetOpaque(const lldb::DisassemblerSP &disasm_sp,
                              const lldb::InstructionSP &inst_sp) {
  m_opaque_sp.reset(new InstructionImpl(disasm_sp, inst_sp));
}

bool SBInstruction::GetDescription(lldb::SBStream &s) {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    SymbolContext sc;
    const Address &addr = inst_sp->GetAddress();
    ModuleSP module_sp(addr.GetModule());
    if (module_sp)
      module_sp->ResolveSymbolContextForAddress(addr, eSymbolContextEverything,
                                                sc);
    // Use the "ref()" instead of the "get()" accessor in case the SBStream
    // didn't have a stream already created, one will get created...
    FormatEntity::Entry format;
    FormatEntity::Parse("${addr}: ", format);
    inst_sp->Dump(&s.ref(), 0, true, false, NULL, &sc, NULL, &format, 0);
    return true;
  }
  return false;
}

void SBInstruction::Print(FILE *out) {
  if (out == NULL)
    return;

  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    SymbolContext sc;
    const Address &addr = inst_sp->GetAddress();
    ModuleSP module_sp(addr.GetModule());
    if (module_sp)
      module_sp->ResolveSymbolContextForAddress(addr, eSymbolContextEverything,
                                                sc);
    StreamFile out_stream(out, false);
    FormatEntity::Entry format;
    FormatEntity::Parse("${addr}: ", format);
    inst_sp->Dump(&out_stream, 0, true, false, NULL, &sc, NULL, &format, 0);
  }
}

bool SBInstruction::EmulateWithFrame(lldb::SBFrame &frame,
                                     uint32_t evaluate_options) {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp) {
    lldb::StackFrameSP frame_sp(frame.GetFrameSP());

    if (frame_sp) {
      lldb_private::ExecutionContext exe_ctx;
      frame_sp->CalculateExecutionContext(exe_ctx);
      lldb_private::Target *target = exe_ctx.GetTargetPtr();
      lldb_private::ArchSpec arch = target->GetArchitecture();

      return inst_sp->Emulate(
          arch, evaluate_options, (void *)frame_sp.get(),
          &lldb_private::EmulateInstruction::ReadMemoryFrame,
          &lldb_private::EmulateInstruction::WriteMemoryFrame,
          &lldb_private::EmulateInstruction::ReadRegisterFrame,
          &lldb_private::EmulateInstruction::WriteRegisterFrame);
    }
  }
  return false;
}

bool SBInstruction::DumpEmulation(const char *triple) {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp && triple) {
    lldb_private::ArchSpec arch(triple, NULL);
    return inst_sp->DumpEmulation(arch);
  }
  return false;
}

bool SBInstruction::TestEmulation(lldb::SBStream &output_stream,
                                  const char *test_file) {
  if (!m_opaque_sp)
    SetOpaque(lldb::DisassemblerSP(),
              lldb::InstructionSP(new PseudoInstruction()));

  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp)
    return inst_sp->TestEmulation(output_stream.get(), test_file);
  return false;
}

lldb::AddressClass SBInstruction::GetAddressClass() {
  lldb::InstructionSP inst_sp(GetOpaque());
  if (inst_sp)
    return inst_sp->GetAddressClass();
  return eAddressClassInvalid;
}