Disassembler.cpp

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//===-- Disassembler.cpp --------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
 
#include "lldb/Core/Disassembler.h"
 
#include "lldb/Core/AddressRange.h"
#include "lldb/Core/Architecture.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/EmulateInstruction.h"
#include "lldb/Core/Mangled.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleList.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/SourceManager.h"
#include "lldb/Host/FileSystem.h"
#include "lldb/Interpreter/OptionValue.h"
#include "lldb/Interpreter/OptionValueArray.h"
#include "lldb/Interpreter/OptionValueDictionary.h"
#include "lldb/Interpreter/OptionValueRegex.h"
#include "lldb/Interpreter/OptionValueString.h"
#include "lldb/Interpreter/OptionValueUInt64.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/Variable.h"
#include "lldb/Symbol/VariableList.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/RegularExpression.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/Stream.h"
#include "lldb/Utility/StreamString.h"
#include "lldb/Utility/Timer.h"
#include "lldb/lldb-private-enumerations.h"
#include "lldb/lldb-private-interfaces.h"
#include "lldb/lldb-private-types.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Compiler.h"
#include "llvm/TargetParser/Triple.h"
 
#include <cstdint>
#include <cstring>
#include <utility>
 
#include <cassert>
 
#define DEFAULT_DISASM_BYTE_SIZE 32
 
using namespace lldb;
using namespace lldb_private;
 
DisassemblerSP Disassembler::FindPlugin(const ArchSpec &arch,
                                        const char *flavor, const char *cpu,
                                        const char *features,
                                        const char *plugin_name) {
  LLDB_SCOPED_TIMERF("Disassembler::FindPlugin (arch = %s, plugin_name = %s)",
                     arch.GetArchitectureName(), plugin_name);
 
  DisassemblerCreateInstance create_callback = nullptr;
 
  if (plugin_name) {
    create_callback =
        PluginManager::GetDisassemblerCreateCallbackForPluginName(plugin_name);
    if (create_callback) {
      if (auto disasm_sp = create_callback(arch, flavor, cpu, features))
        return disasm_sp;
    }
  } else {
    for (auto create_callback :
         PluginManager::GetDisassemblerCreateCallbacks()) {
      if (auto disasm_sp = create_callback(arch, flavor, cpu, features))
        return disasm_sp;
    }
  }
  return DisassemblerSP();
}
 
DisassemblerSP Disassembler::FindPluginForTarget(
    const Target &target, const ArchSpec &arch, const char *flavor,
    const char *cpu, const char *features, const char *plugin_name) {
  if (!flavor) {
    // FIXME - we don't have the mechanism in place to do per-architecture
    // settings.  But since we know that for now we only support flavors on x86
    // & x86_64,
    if (arch.GetTriple().getArch() == llvm::Triple::x86 ||
        arch.GetTriple().getArch() == llvm::Triple::x86_64)
      flavor = target.GetDisassemblyFlavor();
  }
  if (!cpu)
    cpu = target.GetDisassemblyCPU();
  if (!features)
    features = target.GetDisassemblyFeatures();
 
  return FindPlugin(arch, flavor, cpu, features, plugin_name);
}
 
static Address ResolveAddress(Target &target, const Address &addr) {
  if (!addr.IsSectionOffset()) {
    Address resolved_addr;
    // If we weren't passed in a section offset address range, try and resolve
    // it to something
    bool is_resolved =
        target.HasLoadedSections()
            ? target.ResolveLoadAddress(addr.GetOffset(), resolved_addr)
            : target.GetImages().ResolveFileAddress(addr.GetOffset(),
                                                    resolved_addr);
 
    // We weren't able to resolve the address, just treat it as a raw address
    if (is_resolved && resolved_addr.IsValid())
      return resolved_addr;
  }
  return addr;
}
 
lldb::DisassemblerSP Disassembler::DisassembleRange(
    const ArchSpec &arch, const char *plugin_name, const char *flavor,
    const char *cpu, const char *features, Target &target,
    llvm::ArrayRef<AddressRange> disasm_ranges, bool force_live_memory) {
  lldb::DisassemblerSP disasm_sp = Disassembler::FindPluginForTarget(
      target, arch, flavor, cpu, features, plugin_name);
 
  if (!disasm_sp)
    return {};
 
  size_t bytes_disassembled = 0;
  for (const AddressRange &range : disasm_ranges) {
    bytes_disassembled += disasm_sp->AppendInstructions(
        target, range.GetBaseAddress(), {Limit::Bytes, range.GetByteSize()},
        nullptr, force_live_memory);
  }
  if (bytes_disassembled == 0)
    return {};
 
  return disasm_sp;
}
 
lldb::DisassemblerSP
Disassembler::DisassembleBytes(const ArchSpec &arch, const char *plugin_name,
                               const char *flavor, const char *cpu,
                               const char *features, const Address &start,
                               const void *src, size_t src_len,
                               uint32_t num_instructions, bool data_from_file) {
  if (!src)
    return {};
 
  lldb::DisassemblerSP disasm_sp =
      Disassembler::FindPlugin(arch, flavor, cpu, features, plugin_name);
 
  if (!disasm_sp)
    return {};
 
  DataExtractor data(src, src_len, arch.GetByteOrder(),
                     arch.GetAddressByteSize());
 
  (void)disasm_sp->DecodeInstructions(start, data, 0, num_instructions, false,
                                      data_from_file);
  return disasm_sp;
}
 
bool Disassembler::Disassemble(Debugger &debugger, const ArchSpec &arch,
                               const char *plugin_name, const char *flavor,
                               const char *cpu, const char *features,
                               const ExecutionContext &exe_ctx,
                               const Address &address, Limit limit,
                               bool mixed_source_and_assembly,
                               uint32_t num_mixed_context_lines,
                               uint32_t options, Stream &strm) {
  if (!exe_ctx.GetTargetPtr())
    return false;
 
  lldb::DisassemblerSP disasm_sp(Disassembler::FindPluginForTarget(
      exe_ctx.GetTargetRef(), arch, flavor, cpu, features, plugin_name));
  if (!disasm_sp)
    return false;
 
  const bool force_live_memory = true;
  size_t bytes_disassembled = disasm_sp->ParseInstructions(
      exe_ctx.GetTargetRef(), address, limit, &strm, force_live_memory);
  if (bytes_disassembled == 0)
    return false;
 
  disasm_sp->PrintInstructions(debugger, arch, exe_ctx,
                               mixed_source_and_assembly,
                               num_mixed_context_lines, options, strm);
  return true;
}
 
Disassembler::SourceLine
Disassembler::GetFunctionDeclLineEntry(const SymbolContext &sc) {
  if (!sc.function)
    return {};
 
  if (!sc.line_entry.IsValid())
    return {};
 
  LineEntry prologue_end_line = sc.line_entry;
  SupportFileNSP func_decl_file_sp = std::make_shared<SupportFile>();
  uint32_t func_decl_line;
  sc.function->GetStartLineSourceInfo(func_decl_file_sp, func_decl_line);
 
  if (!func_decl_file_sp)
    return {};
  if (!func_decl_file_sp->Equal(*prologue_end_line.file_sp,
                                SupportFile::eEqualFileSpecAndChecksumIfSet) &&
      !func_decl_file_sp->Equal(*prologue_end_line.original_file_sp,
                                SupportFile::eEqualFileSpecAndChecksumIfSet))
    return {};
 
  SourceLine decl_line;
  decl_line.file = func_decl_file_sp->GetSpecOnly();
  decl_line.line = func_decl_line;
  // TODO: Do we care about column on these entries?  If so, we need to plumb
  // that through GetStartLineSourceInfo.
  decl_line.column = 0;
  return decl_line;
}
 
void Disassembler::AddLineToSourceLineTables(
    SourceLine &line,
    std::map<FileSpec, std::set<uint32_t>> &source_lines_seen) {
  if (line.IsValid()) {
    auto source_lines_seen_pos = source_lines_seen.find(line.file);
    if (source_lines_seen_pos == source_lines_seen.end()) {
      std::set<uint32_t> lines;
      lines.insert(line.line);
      source_lines_seen.emplace(line.file, lines);
    } else {
      source_lines_seen_pos->second.insert(line.line);
    }
  }
}
 
bool Disassembler::ElideMixedSourceAndDisassemblyLine(
    const ExecutionContext &exe_ctx, const SymbolContext &sc,
    SourceLine &line) {
 
  // TODO: should we also check target.process.thread.step-avoid-libraries ?
 
  const RegularExpression *avoid_regex = nullptr;
 
  // Skip any line #0 entries - they are implementation details
  if (line.line == 0)
    return true;
 
  ThreadSP thread_sp = exe_ctx.GetThreadSP();
  if (thread_sp) {
    avoid_regex = thread_sp->GetSymbolsToAvoidRegexp();
  } else {
    TargetSP target_sp = exe_ctx.GetTargetSP();
    if (target_sp) {
      Status error;
      OptionValueSP value_sp = target_sp->GetDebugger().GetPropertyValue(
          &exe_ctx, "target.process.thread.step-avoid-regexp", error);
      if (value_sp && value_sp->GetType() == OptionValue::eTypeRegex) {
        OptionValueRegex *re = value_sp->GetAsRegex();
        if (re) {
          avoid_regex = re->GetCurrentValue();
        }
      }
    }
  }
  if (avoid_regex && sc.symbol != nullptr) {
    const char *function_name =
        sc.GetFunctionName(Mangled::ePreferDemangledWithoutArguments)
            .GetCString();
    if (function_name && avoid_regex->Execute(function_name)) {
      // skip this source line
      return true;
    }
  }
  // don't skip this source line
  return false;
}
 
static constexpr const llvm::StringLiteral kUndefLocation = "undef";
static constexpr const llvm::StringLiteral kUndefLocationFormatted = "<undef>";
static void
AddVariableAnnotationToVector(std::vector<VariableAnnotation> &annotations,
                              VariableAnnotation annotation_entity,
                              const bool is_live) {
  annotation_entity.is_live = is_live;
  if (!is_live)
    annotation_entity.location_description = kUndefLocation;
  annotations.push_back(std::move(annotation_entity));
}
 
// For each instruction, this block attempts to resolve in-scope variables
// and determine if the current PC falls within their
// DWARF location entry. If so, it prints a simplified annotation using the
// variable name and its resolved location (e.g., "var = reg; " ).
//
// Annotations are only included if the variable has a valid DWARF location
// entry, and the location string is non-empty after filtering. Decoding
// errors and DWARF opcodes are intentionally omitted to keep the output
// concise and user-friendly.
//
// The goal is to give users helpful live variable hints alongside the
// disassembled instruction stream, similar to how debug information
// enhances source-level debugging.
std::vector<std::string> VariableAnnotator::Annotate(Instruction &inst) {
  std::vector<VariableAnnotation> structured_annotations =
      AnnotateStructured(inst);
 
  std::vector<std::string> events;
  events.reserve(structured_annotations.size());
 
  for (const VariableAnnotation &annotation : structured_annotations) {
    const llvm::StringRef location =
        (annotation.location_description == kUndefLocation
             ? llvm::StringRef(kUndefLocationFormatted)
             : llvm::StringRef(annotation.location_description));
 
    events.push_back(
        llvm::formatv("{0} = {1}", annotation.variable_name, location).str());
  }
 
  return events;
}
 
std::vector<VariableAnnotation>
VariableAnnotator::AnnotateStructured(Instruction &inst) {
  std::vector<VariableAnnotation> annotations;
 
  auto module_sp = inst.GetAddress().GetModule();
 
  // If we lost module context, mark all live variables as UndefLocation.
  if (!module_sp) {
    for (const auto &KV : m_live_vars)
      AddVariableAnnotationToVector(annotations, KV.second, false);
    m_live_vars.clear();
    return annotations;
  }
 
  // Resolve function/block at this *file* address.
  SymbolContext sc;
  const Address &iaddr = inst.GetAddress();
  const auto mask = eSymbolContextFunction | eSymbolContextBlock;
  if (!module_sp->ResolveSymbolContextForAddress(iaddr, mask, sc) ||
      !sc.function) {
    // No function context: everything dies here.
    for (const auto &KV : m_live_vars)
      AddVariableAnnotationToVector(annotations, KV.second, false);
    m_live_vars.clear();
    return annotations;
  }
 
  // Collect in-scope variables for this instruction into current_vars.
  VariableList var_list;
  // Innermost block containing iaddr.
  if (Block *B = sc.block) {
    auto filter = [](Variable *v) -> bool { return v && !v->IsArtificial(); };
    B->AppendVariables(/*can_create*/ true,
                       /*get_parent_variables*/ true,
                       /*stop_if_block_is_inlined_function*/ false,
                       /*filter*/ filter,
                       /*variable_list*/ &var_list);
  }
 
  const lldb::addr_t pc_file = iaddr.GetFileAddress();
  const lldb::addr_t func_file = sc.function->GetAddress().GetFileAddress();
 
  // ABI from Target (pretty reg names if plugin exists). Safe to be null.
  lldb::ABISP abi_sp = ABI::FindPlugin(nullptr, module_sp->GetArchitecture());
  ABI *abi = abi_sp.get();
 
  llvm::DIDumpOptions opts;
  opts.ShowAddresses = false;
  // Prefer "register-only" output when we have an ABI.
  opts.PrintRegisterOnly = static_cast<bool>(abi_sp);
 
  llvm::DenseMap<lldb::user_id_t, VariableAnnotation> current_vars;
 
  for (size_t i = 0, e = var_list.GetSize(); i != e; ++i) {
    lldb::VariableSP v = var_list.GetVariableAtIndex(i);
    if (!v || v->IsArtificial())
      continue;
 
    const char *nm = v->GetName().AsCString(nullptr);
    llvm::StringRef name = nm ? nm : "<anon>";
 
    DWARFExpressionList &exprs = v->LocationExpressionList();
    if (!exprs.IsValid())
      continue;
 
    auto entry_or_err = exprs.GetExpressionEntryAtAddress(func_file, pc_file);
    if (!entry_or_err)
      continue;
 
    auto entry = *entry_or_err;
 
    StreamString loc_ss;
    entry.expr->DumpLocation(&loc_ss, eDescriptionLevelBrief, abi, opts);
 
    llvm::StringRef loc = llvm::StringRef(loc_ss.GetString()).trim();
    if (loc.empty())
      continue;
 
    std::optional<std::string> decl_file;
    std::optional<uint32_t> decl_line;
    std::optional<std::string> type_name;
 
    const Declaration &decl = v->GetDeclaration();
    if (decl.GetFile()) {
      decl_file = decl.GetFile().GetFilename().str();
      if (decl.GetLine() > 0)
        decl_line = decl.GetLine();
    }
 
    if (Type *type = v->GetType())
      if (const char *type_str = type->GetName().AsCString(nullptr))
        type_name = type_str;
 
    current_vars.try_emplace(
        v->GetID(),
        VariableAnnotation{std::string(name), std::string(loc), true,
                           entry.expr->GetRegisterKind(), entry.file_range,
                           decl_file, decl_line, type_name});
  }
 
  // Diff m_live_vars → current_vars.
 
  // 1) Starts/changes: iterate current_vars and compare with m_live_vars.
  for (const auto &KV : current_vars) {
    auto it = m_live_vars.find(KV.first);
    if (it == m_live_vars.end())
      // Newly live.
      AddVariableAnnotationToVector(annotations, KV.second, true);
    else if (it->second.location_description != KV.second.location_description)
      // Location changed.
      AddVariableAnnotationToVector(annotations, KV.second, true);
  }
 
  // 2) Ends: anything that was live but is not in current_vars becomes
  // UndefLocation.
  for (const auto &KV : m_live_vars)
    if (!current_vars.count(KV.first))
      AddVariableAnnotationToVector(annotations, KV.second, false);
 
  // Commit new state.
  m_live_vars = std::move(current_vars);
  return annotations;
}
 
void Disassembler::PrintInstructions(Debugger &debugger, const ArchSpec &arch,
                                     const ExecutionContext &exe_ctx,
                                     bool mixed_source_and_assembly,
                                     uint32_t num_mixed_context_lines,
                                     uint32_t options, Stream &strm) {
  // We got some things disassembled...
  size_t num_instructions_found = GetInstructionList().GetSize();
 
  const uint32_t max_opcode_byte_size =
      GetInstructionList().GetMaxOpcocdeByteSize();
  SymbolContext sc;
  SymbolContext prev_sc;
  AddressRange current_source_line_range;
  const Address *pc_addr_ptr = nullptr;
  StackFrame *frame = exe_ctx.GetFramePtr();
 
  TargetSP target_sp(exe_ctx.GetTargetSP());
  SourceManager &source_manager =
      target_sp ? target_sp->GetSourceManager() : debugger.GetSourceManager();
 
  if (frame) {
    pc_addr_ptr = &frame->GetFrameCodeAddress();
  }
  const uint32_t scope =
      eSymbolContextLineEntry | eSymbolContextFunction | eSymbolContextSymbol;
  const bool use_inline_block_range = false;
 
  const FormatEntity::Entry *disassembly_format = nullptr;
  FormatEntity::Entry format;
  if (exe_ctx.HasTargetScope()) {
    format = exe_ctx.GetTargetRef().GetDebugger().GetDisassemblyFormat();
    disassembly_format = &format;
  } else {
    FormatEntity::Parse("${addr}: ", format);
    disassembly_format = &format;
  }
 
  // First pass: step through the list of instructions, find how long the
  // initial addresses strings are, insert padding in the second pass so the
  // opcodes all line up nicely.
 
  // Also build up the source line mapping if this is mixed source & assembly
  // mode. Calculate the source line for each assembly instruction (eliding
  // inlined functions which the user wants to skip).
 
  std::map<FileSpec, std::set<uint32_t>> source_lines_seen;
  const Symbol *previous_symbol = nullptr;
 
  size_t address_text_size = 0;
  for (size_t i = 0; i < num_instructions_found; ++i) {
    Instruction *inst = GetInstructionList().GetInstructionAtIndex(i).get();
    if (inst) {
      const Address &addr = inst->GetAddress();
      ModuleSP module_sp(addr.GetModule());
      if (module_sp) {
        const SymbolContextItem resolve_mask = eSymbolContextFunction |
                                               eSymbolContextSymbol |
                                               eSymbolContextLineEntry;
        uint32_t resolved_mask =
            module_sp->ResolveSymbolContextForAddress(addr, resolve_mask, sc);
        if (resolved_mask) {
          StreamString strmstr;
          Debugger::FormatDisassemblerAddress(disassembly_format, &sc, nullptr,
                                              &exe_ctx, &addr, strmstr);
          size_t cur_line = strmstr.GetSizeOfLastLine();
          if (cur_line > address_text_size)
            address_text_size = cur_line;
 
          // Add entries to our "source_lines_seen" map+set which list which
          // sources lines occur in this disassembly session.  We will print
          // lines of context around a source line, but we don't want to print
          // a source line that has a line table entry of its own - we'll leave
          // that source line to be printed when it actually occurs in the
          // disassembly.
 
          if (mixed_source_and_assembly && sc.line_entry.IsValid()) {
            if (sc.symbol != previous_symbol) {
              SourceLine decl_line = GetFunctionDeclLineEntry(sc);
              if (!ElideMixedSourceAndDisassemblyLine(exe_ctx, sc, decl_line))
                AddLineToSourceLineTables(decl_line, source_lines_seen);
            }
            if (sc.line_entry.IsValid()) {
              SourceLine this_line;
              this_line.file = sc.line_entry.GetFile();
              this_line.line = sc.line_entry.line;
              this_line.column = sc.line_entry.column;
              if (!ElideMixedSourceAndDisassemblyLine(exe_ctx, sc, this_line))
                AddLineToSourceLineTables(this_line, source_lines_seen);
            }
          }
        }
        sc.Clear(false);
      }
    }
  }
 
  VariableAnnotator annot;
  previous_symbol = nullptr;
  SourceLine previous_line;
  for (size_t i = 0; i < num_instructions_found; ++i) {
    Instruction *inst = GetInstructionList().GetInstructionAtIndex(i).get();
 
    if (inst) {
      const Address &addr = inst->GetAddress();
      const bool inst_is_at_pc = pc_addr_ptr && addr == *pc_addr_ptr;
      SourceLinesToDisplay source_lines_to_display;
 
      prev_sc = sc;
 
      ModuleSP module_sp(addr.GetModule());
      if (module_sp) {
        uint32_t resolved_mask = module_sp->ResolveSymbolContextForAddress(
            addr, eSymbolContextEverything, sc);
        if (resolved_mask) {
          if (mixed_source_and_assembly) {
 
            // If we've started a new function (non-inlined), print all of the
            // source lines from the function declaration until the first line
            // table entry - typically the opening curly brace of the function.
            if (previous_symbol != sc.symbol) {
              // The default disassembly format puts an extra blank line
              // between functions - so when we're displaying the source
              // context for a function, we don't want to add a blank line
              // after the source context or we'll end up with two of them.
              if (previous_symbol != nullptr)
                source_lines_to_display.print_source_context_end_eol = false;
 
              previous_symbol = sc.symbol;
              if (sc.function && sc.line_entry.IsValid()) {
                LineEntry prologue_end_line = sc.line_entry;
                if (!ElideMixedSourceAndDisassemblyLine(exe_ctx, sc,
                                                        prologue_end_line)) {
                  SupportFileNSP func_decl_file_sp =
                      std::make_shared<SupportFile>();
                  uint32_t func_decl_line;
                  sc.function->GetStartLineSourceInfo(func_decl_file_sp,
                                                      func_decl_line);
                  if (func_decl_file_sp &&
                      (func_decl_file_sp->Equal(
                           *prologue_end_line.file_sp,
                           SupportFile::eEqualFileSpecAndChecksumIfSet) ||
                       func_decl_file_sp->Equal(
                           *prologue_end_line.original_file_sp,
                           SupportFile::eEqualFileSpecAndChecksumIfSet))) {
                    // Add all the lines between the function declaration and
                    // the first non-prologue source line to the list of lines
                    // to print.
                    for (uint32_t lineno = func_decl_line;
                         lineno <= prologue_end_line.line; lineno++) {
                      SourceLine this_line;
                      this_line.file = func_decl_file_sp->GetSpecOnly();
                      this_line.line = lineno;
                      source_lines_to_display.lines.push_back(this_line);
                    }
                    // Mark the last line as the "current" one.  Usually this
                    // is the open curly brace.
                    if (source_lines_to_display.lines.size() > 0)
                      source_lines_to_display.current_source_line =
                          source_lines_to_display.lines.size() - 1;
                  }
                }
              }
              sc.GetAddressRange(scope, 0, use_inline_block_range,
                                 current_source_line_range);
            }
 
            // If we've left a previous source line's address range, print a
            // new source line
            if (!current_source_line_range.ContainsFileAddress(addr)) {
              sc.GetAddressRange(scope, 0, use_inline_block_range,
                                 current_source_line_range);
 
              if (sc != prev_sc && sc.comp_unit && sc.line_entry.IsValid()) {
                SourceLine this_line;
                this_line.file = sc.line_entry.GetFile();
                this_line.line = sc.line_entry.line;
 
                if (!ElideMixedSourceAndDisassemblyLine(exe_ctx, sc,
                                                        this_line)) {
                  // Only print this source line if it is different from the
                  // last source line we printed.  There may have been inlined
                  // functions between these lines that we elided, resulting in
                  // the same line being printed twice in a row for a
                  // contiguous block of assembly instructions.
                  if (this_line != previous_line) {
 
                    std::vector<uint32_t> previous_lines;
                    for (uint32_t i = 0;
                         i < num_mixed_context_lines &&
                         (this_line.line - num_mixed_context_lines) > 0;
                         i++) {
                      uint32_t line =
                          this_line.line - num_mixed_context_lines + i;
                      auto pos = source_lines_seen.find(this_line.file);
                      if (pos != source_lines_seen.end()) {
                        if (pos->second.count(line) == 1) {
                          previous_lines.clear();
                        } else {
                          previous_lines.push_back(line);
                        }
                      }
                    }
                    for (size_t i = 0; i < previous_lines.size(); i++) {
                      SourceLine previous_line;
                      previous_line.file = this_line.file;
                      previous_line.line = previous_lines[i];
                      auto pos = source_lines_seen.find(previous_line.file);
                      if (pos != source_lines_seen.end()) {
                        pos->second.insert(previous_line.line);
                      }
                      source_lines_to_display.lines.push_back(previous_line);
                    }
 
                    source_lines_to_display.lines.push_back(this_line);
                    source_lines_to_display.current_source_line =
                        source_lines_to_display.lines.size() - 1;
 
                    for (uint32_t i = 0; i < num_mixed_context_lines; i++) {
                      SourceLine next_line;
                      next_line.file = this_line.file;
                      next_line.line = this_line.line + i + 1;
                      auto pos = source_lines_seen.find(next_line.file);
                      if (pos != source_lines_seen.end()) {
                        if (pos->second.count(next_line.line) == 1)
                          break;
                        pos->second.insert(next_line.line);
                      }
                      source_lines_to_display.lines.push_back(next_line);
                    }
                  }
                  previous_line = this_line;
                }
              }
            }
          }
        } else {
          sc.Clear(true);
        }
      }
 
      if (source_lines_to_display.lines.size() > 0) {
        strm.EOL();
        for (size_t idx = 0; idx < source_lines_to_display.lines.size();
             idx++) {
          SourceLine ln = source_lines_to_display.lines[idx];
          const char *line_highlight = "";
          if (inst_is_at_pc && (options & eOptionMarkPCSourceLine)) {
            line_highlight = "->";
          } else if (idx == source_lines_to_display.current_source_line) {
            line_highlight = "**";
          }
          source_manager.DisplaySourceLinesWithLineNumbers(
              std::make_shared<SupportFile>(ln.file), ln.line, ln.column, 0, 0,
              line_highlight, &strm);
        }
        if (source_lines_to_display.print_source_context_end_eol)
          strm.EOL();
      }
 
      const bool show_bytes = (options & eOptionShowBytes) != 0;
      const bool show_control_flow_kind =
          (options & eOptionShowControlFlowKind) != 0;
 
      StreamString inst_line;
 
      inst->Dump(&inst_line, max_opcode_byte_size, true, show_bytes,
                 show_control_flow_kind, &exe_ctx, &sc, &prev_sc, nullptr,
                 address_text_size);
 
      if ((options & eOptionVariableAnnotations) && target_sp) {
        auto annotations = annot.Annotate(*inst);
        if (!annotations.empty()) {
          const size_t annotation_column = 100;
          inst_line.FillLastLineToColumn(annotation_column, ' ');
          inst_line.PutCString("; ");
          inst_line.PutCString(llvm::join(annotations, ", "));
        }
      }
 
      strm.PutCString(inst_line.GetString());
      strm.EOL();
 
    } else {
      break;
    }
  }
}
 
bool Disassembler::Disassemble(Debugger &debugger, const ArchSpec &arch,
                               StackFrame &frame, Stream &strm) {
  constexpr const char *plugin_name = nullptr;
  constexpr const char *flavor = nullptr;
  constexpr const char *cpu = nullptr;
  constexpr const char *features = nullptr;
  constexpr bool mixed_source_and_assembly = false;
  constexpr uint32_t num_mixed_context_lines = 0;
  constexpr uint32_t options = 0;
 
  SymbolContext sc(
      frame.GetSymbolContext(eSymbolContextFunction | eSymbolContextSymbol));
  if (sc.function) {
    if (DisassemblerSP disasm_sp = DisassembleRange(
            arch, plugin_name, flavor, cpu, features, *frame.CalculateTarget(),
            sc.function->GetAddressRanges())) {
      disasm_sp->PrintInstructions(debugger, arch, frame,
                                   mixed_source_and_assembly,
                                   num_mixed_context_lines, options, strm);
      return true;
    }
    return false;
  }
 
  AddressRange range;
  if (sc.symbol && sc.symbol->ValueIsAddress()) {
    range.GetBaseAddress() = sc.symbol->GetAddressRef();
    range.SetByteSize(sc.symbol->GetByteSize());
  } else {
    range.GetBaseAddress() = frame.GetFrameCodeAddress();
  }
 
  if (range.GetBaseAddress().IsValid() && range.GetByteSize() == 0)
    range.SetByteSize(DEFAULT_DISASM_BYTE_SIZE);
 
  Disassembler::Limit limit = {Disassembler::Limit::Bytes, range.GetByteSize()};
  if (limit.value == 0)
    limit.value = DEFAULT_DISASM_BYTE_SIZE;
 
  return Disassemble(debugger, arch, plugin_name, flavor, cpu, features, frame,
                     range.GetBaseAddress(), limit, mixed_source_and_assembly,
                     num_mixed_context_lines, options, strm);
}
 
Instruction::Instruction(const Address &address, AddressClass addr_class)
    : m_address(address), m_address_class(addr_class), m_opcode(),
      m_calculated_strings(false) {}
 
Instruction::~Instruction() = default;
 
AddressClass Instruction::GetAddressClass() {
  if (m_address_class == AddressClass::eInvalid)
    m_address_class = m_address.GetAddressClass();
  return m_address_class;
}
 
const char *Instruction::GetNameForInstructionControlFlowKind(
    lldb::InstructionControlFlowKind instruction_control_flow_kind) {
  switch (instruction_control_flow_kind) {
  case eInstructionControlFlowKindUnknown:
    return "unknown";
  case eInstructionControlFlowKindOther:
    return "other";
  case eInstructionControlFlowKindCall:
    return "call";
  case eInstructionControlFlowKindReturn:
    return "return";
  case eInstructionControlFlowKindJump:
    return "jump";
  case eInstructionControlFlowKindCondJump:
    return "cond jump";
  case eInstructionControlFlowKindFarCall:
    return "far call";
  case eInstructionControlFlowKindFarReturn:
    return "far return";
  case eInstructionControlFlowKindFarJump:
    return "far jump";
  }
  llvm_unreachable("Fully covered switch above!");
}
 
void Instruction::Dump(lldb_private::Stream *s, uint32_t max_opcode_byte_size,
                       bool show_address, bool show_bytes,
                       bool show_control_flow_kind,
                       const ExecutionContext *exe_ctx,
                       const SymbolContext *sym_ctx,
                       const SymbolContext *prev_sym_ctx,
                       const FormatEntity::Entry *disassembly_addr_format,
                       size_t max_address_text_size) {
  size_t opcode_column_width = 7;
  const size_t operand_column_width = 25;
 
  CalculateMnemonicOperandsAndCommentIfNeeded(exe_ctx);
 
  StreamString ss;
 
  if (show_address) {
    Debugger::FormatDisassemblerAddress(disassembly_addr_format, sym_ctx,
                                        prev_sym_ctx, exe_ctx, &m_address, ss);
    ss.FillLastLineToColumn(max_address_text_size, ' ');
  }
 
  if (show_bytes) {
    if (m_opcode.GetType() == Opcode::eTypeBytes) {
      // x86_64 and i386 are the only ones that use bytes right now so pad out
      // the byte dump to be able to always show 15 bytes (3 chars each) plus a
      // space
      if (max_opcode_byte_size > 0)
        m_opcode.Dump(&ss, max_opcode_byte_size * 3 + 1);
      else
        m_opcode.Dump(&ss, 15 * 3 + 1);
    } else {
      // Else, we have ARM or MIPS which can show up to a uint32_t 0x00000000
      // (10 spaces) plus two for padding...
      if (max_opcode_byte_size > 0)
        m_opcode.Dump(&ss, max_opcode_byte_size * 3 + 1);
      else
        m_opcode.Dump(&ss, 12);
    }
  }
 
  if (show_control_flow_kind) {
    lldb::InstructionControlFlowKind instruction_control_flow_kind =
        GetControlFlowKind(exe_ctx);
    ss.Printf("%-12s", GetNameForInstructionControlFlowKind(
                           instruction_control_flow_kind));
  }
 
  bool show_color = false;
  if (exe_ctx) {
    if (TargetSP target_sp = exe_ctx->GetTargetSP()) {
      show_color = target_sp->GetDebugger().GetUseColor();
    }
  }
  const size_t opcode_pos = ss.GetSizeOfLastLine();
  std::string &opcode_name = show_color ? m_markup_opcode_name : m_opcode_name;
  const std::string &mnemonics = show_color ? m_markup_mnemonics : m_mnemonics;
 
  if (opcode_name.empty())
    opcode_name = "<unknown>";
 
  // The default opcode size of 7 characters is plenty for most architectures
  // but some like arm can pull out the occasional vqrshrun.s16.  We won't get
  // consistent column spacing in these cases, unfortunately. Also note that we
  // need to directly use m_opcode_name here (instead of opcode_name) so we
  // don't include color codes as characters.
  if (m_opcode_name.length() >= opcode_column_width) {
    opcode_column_width = m_opcode_name.length() + 1;
  }
 
  ss.PutCString(opcode_name);
  ss.FillLastLineToColumn(opcode_pos + opcode_column_width, ' ');
  ss.PutCString(mnemonics);
 
  if (!m_comment.empty()) {
    ss.FillLastLineToColumn(
        opcode_pos + opcode_column_width + operand_column_width, ' ');
    ss.PutCString(" ; ");
    ss.PutCString(m_comment);
  }
  s->PutCString(ss.GetString());
}
 
bool Instruction::DumpEmulation(const ArchSpec &arch) {
  std::unique_ptr<EmulateInstruction> insn_emulator_up(
      EmulateInstruction::FindPlugin(arch, eInstructionTypeAny, nullptr));
  if (insn_emulator_up) {
    insn_emulator_up->SetInstruction(GetOpcode(), GetAddress(), nullptr);
    return insn_emulator_up->EvaluateInstruction(0);
  }
 
  return false;
}
 
bool Instruction::CanSetBreakpoint() { return !HasDelaySlot(); }
 
bool Instruction::HasDelaySlot() {
  // Default is false.
  return false;
}
 
OptionValueSP Instruction::ReadArray(FILE *in_file, Stream &out_stream,
                                     OptionValue::Type data_type) {
  bool done = false;
  char buffer[1024];
 
  auto option_value_sp = std::make_shared<OptionValueArray>(1u << data_type);
 
  int idx = 0;
  while (!done) {
    if (!fgets(buffer, 1023, in_file)) {
      out_stream.Printf(
          "Instruction::ReadArray:  Error reading file (fgets).\n");
      option_value_sp.reset();
      return option_value_sp;
    }
 
    std::string line(buffer);
 
    size_t len = line.size();
    if (line[len - 1] == '\n') {
      line[len - 1] = '\0';
      line.resize(len - 1);
    }
 
    if ((line.size() == 1) && line[0] == ']') {
      done = true;
      line.clear();
    }
 
    if (!line.empty()) {
      std::string value;
      static RegularExpression g_reg_exp(
          llvm::StringRef("^[ \t]*([^ \t]+)[ \t]*$"));
      llvm::SmallVector<llvm::StringRef, 2> matches;
      if (g_reg_exp.Execute(line, &matches))
        value = matches[1].str();
      else
        value = line;
 
      OptionValueSP data_value_sp;
      switch (data_type) {
      case OptionValue::eTypeUInt64:
        data_value_sp = std::make_shared<OptionValueUInt64>(0, 0);
        data_value_sp->SetValueFromString(value);
        break;
      // Other types can be added later as needed.
      default:
        data_value_sp = std::make_shared<OptionValueString>(value.c_str(), "");
        break;
      }
 
      option_value_sp->GetAsArray()->InsertValue(idx, data_value_sp);
      ++idx;
    }
  }
 
  return option_value_sp;
}
 
OptionValueSP Instruction::ReadDictionary(FILE *in_file, Stream &out_stream) {
  bool done = false;
  char buffer[1024];
 
  auto option_value_sp = std::make_shared<OptionValueDictionary>();
  static constexpr llvm::StringLiteral encoding_key("data_encoding");
  OptionValue::Type data_type = OptionValue::eTypeInvalid;
 
  while (!done) {
    // Read the next line in the file
    if (!fgets(buffer, 1023, in_file)) {
      out_stream.Printf(
          "Instruction::ReadDictionary: Error reading file (fgets).\n");
      option_value_sp.reset();
      return option_value_sp;
    }
 
    // Check to see if the line contains the end-of-dictionary marker ("}")
    std::string line(buffer);
 
    size_t len = line.size();
    if (line[len - 1] == '\n') {
      line[len - 1] = '\0';
      line.resize(len - 1);
    }
 
    if ((line.size() == 1) && (line[0] == '}')) {
      done = true;
      line.clear();
    }
 
    // Try to find a key-value pair in the current line and add it to the
    // dictionary.
    if (!line.empty()) {
      static RegularExpression g_reg_exp(llvm::StringRef(
          "^[ \t]*([a-zA-Z_][a-zA-Z0-9_]*)[ \t]*=[ \t]*(.*)[ \t]*$"));
 
      llvm::SmallVector<llvm::StringRef, 3> matches;
 
      bool reg_exp_success = g_reg_exp.Execute(line, &matches);
      std::string key;
      std::string value;
      if (reg_exp_success) {
        key = matches[1].str();
        value = matches[2].str();
      } else {
        out_stream.Printf("Instruction::ReadDictionary: Failure executing "
                          "regular expression.\n");
        option_value_sp.reset();
        return option_value_sp;
      }
 
      // Check value to see if it's the start of an array or dictionary.
 
      lldb::OptionValueSP value_sp;
      assert(value.empty() == false);
      assert(key.empty() == false);
 
      if (value[0] == '{') {
        assert(value.size() == 1);
        // value is a dictionary
        value_sp = ReadDictionary(in_file, out_stream);
        if (!value_sp) {
          option_value_sp.reset();
          return option_value_sp;
        }
      } else if (value[0] == '[') {
        assert(value.size() == 1);
        // value is an array
        value_sp = ReadArray(in_file, out_stream, data_type);
        if (!value_sp) {
          option_value_sp.reset();
          return option_value_sp;
        }
        // We've used the data_type to read an array; re-set the type to
        // Invalid
        data_type = OptionValue::eTypeInvalid;
      } else if ((value[0] == '0') && (value[1] == 'x')) {
        value_sp = std::make_shared<OptionValueUInt64>(0, 0);
        value_sp->SetValueFromString(value);
      } else {
        size_t len = value.size();
        if ((value[0] == '"') && (value[len - 1] == '"'))
          value = value.substr(1, len - 2);
        value_sp = std::make_shared<OptionValueString>(value.c_str(), "");
      }
 
      if (key == encoding_key) {
        // A 'data_encoding=..." is NOT a normal key-value pair; it is meta-data
        // indicating the data type of an upcoming array (usually the next bit
        // of data to be read in).
        if (llvm::StringRef(value) == "uint32_t")
          data_type = OptionValue::eTypeUInt64;
      } else
        option_value_sp->GetAsDictionary()->SetValueForKey(key, value_sp,
                                                           false);
    }
  }
 
  return option_value_sp;
}
 
bool Instruction::TestEmulation(Stream &out_stream, const char *file_name) {
  if (!file_name) {
    out_stream.PutCString("Instruction::TestEmulation:  Missing file_name.");
    return false;
  }
  FILE *test_file = FileSystem::Instance().Fopen(file_name, "r");
  if (!test_file) {
    out_stream.Printf(
        "Instruction::TestEmulation: Attempt to open test file failed.");
    return false;
  }
 
  char buffer[256];
  if (!fgets(buffer, 255, test_file)) {
    out_stream.Printf(
        "Instruction::TestEmulation: Error reading first line of test file.\n");
    fclose(test_file);
    return false;
  }
 
  if (strncmp(buffer, "InstructionEmulationState={", 27) != 0) {
    out_stream.Printf("Instructin::TestEmulation: Test file does not contain "
                      "emulation state dictionary\n");
    fclose(test_file);
    return false;
  }
 
  // Read all the test information from the test file into an
  // OptionValueDictionary.
 
  OptionValueSP data_dictionary_sp(ReadDictionary(test_file, out_stream));
  if (!data_dictionary_sp) {
    out_stream.Printf(
        "Instruction::TestEmulation:  Error reading Dictionary Object.\n");
    fclose(test_file);
    return false;
  }
 
  fclose(test_file);
 
  OptionValueDictionary *data_dictionary =
      data_dictionary_sp->GetAsDictionary();
  static constexpr llvm::StringLiteral description_key("assembly_string");
  static constexpr llvm::StringLiteral triple_key("triple");
 
  OptionValueSP value_sp = data_dictionary->GetValueForKey(description_key);
 
  if (!value_sp) {
    out_stream.Printf("Instruction::TestEmulation:  Test file does not "
                      "contain description string.\n");
    return false;
  }
 
  SetDescription(value_sp->GetValueAs<llvm::StringRef>().value_or(""));
 
  value_sp = data_dictionary->GetValueForKey(triple_key);
  if (!value_sp) {
    out_stream.Printf(
        "Instruction::TestEmulation: Test file does not contain triple.\n");
    return false;
  }
 
  ArchSpec arch;
  arch.SetTriple(
      llvm::Triple(value_sp->GetValueAs<llvm::StringRef>().value_or("")));
 
  bool success = false;
  std::unique_ptr<EmulateInstruction> insn_emulator_up(
      EmulateInstruction::FindPlugin(arch, eInstructionTypeAny, nullptr));
  if (insn_emulator_up)
    success =
        insn_emulator_up->TestEmulation(out_stream, arch, data_dictionary);
 
  if (success)
    out_stream.PutCString("Emulation test succeeded.");
  else
    out_stream.PutCString("Emulation test failed.");
 
  return success;
}
 
bool Instruction::Emulate(
    const ArchSpec &arch, uint32_t evaluate_options, void *baton,
    EmulateInstruction::ReadMemoryCallback read_mem_callback,
    EmulateInstruction::WriteMemoryCallback write_mem_callback,
    EmulateInstruction::ReadRegisterCallback read_reg_callback,
    EmulateInstruction::WriteRegisterCallback write_reg_callback) {
  std::unique_ptr<EmulateInstruction> insn_emulator_up(
      EmulateInstruction::FindPlugin(arch, eInstructionTypeAny, nullptr));
  if (insn_emulator_up) {
    insn_emulator_up->SetBaton(baton);
    insn_emulator_up->SetCallbacks(read_mem_callback, write_mem_callback,
                                   read_reg_callback, write_reg_callback);
    insn_emulator_up->SetInstruction(GetOpcode(), GetAddress(), nullptr);
    return insn_emulator_up->EvaluateInstruction(evaluate_options);
  }
 
  return false;
}
 
uint32_t Instruction::GetData(DataExtractor &data) {
  return m_opcode.GetData(data);
}
 
StructuredData::ArraySP Instruction::GetVariableAnnotations() {
  VariableAnnotator annotator;
  std::vector<VariableAnnotation> annotations =
      annotator.AnnotateStructured(*this);
 
  StructuredData::ArraySP array_sp = std::make_shared<StructuredData::Array>();
 
  for (const VariableAnnotation &ann : annotations) {
    StructuredData::DictionarySP dict_sp =
        std::make_shared<StructuredData::Dictionary>();
 
    dict_sp->AddStringItem("variable_name", ann.variable_name);
    dict_sp->AddStringItem("location_description", ann.location_description);
    if (ann.address_range.has_value()) {
      const auto &range = *ann.address_range;
      dict_sp->AddItem("start_address",
                       std::make_shared<StructuredData::UnsignedInteger>(
                           range.GetBaseAddress().GetFileAddress()));
      dict_sp->AddItem(
          "end_address",
          std::make_shared<StructuredData::UnsignedInteger>(
              range.GetBaseAddress().GetFileAddress() + range.GetByteSize()));
    }
    dict_sp->AddItem(
        "register_kind",
        std::make_shared<StructuredData::UnsignedInteger>(ann.register_kind));
    if (ann.decl_file.has_value())
      dict_sp->AddStringItem("decl_file", *ann.decl_file);
    if (ann.decl_line.has_value())
      dict_sp->AddItem(
          "decl_line",
          std::make_shared<StructuredData::UnsignedInteger>(*ann.decl_line));
    if (ann.type_name.has_value())
      dict_sp->AddStringItem("type_name", *ann.type_name);
 
    array_sp->AddItem(dict_sp);
  }
 
  return array_sp;
}
 
InstructionList::InstructionList() : m_instructions() {}
 
InstructionList::~InstructionList() = default;
 
size_t InstructionList::GetSize() const { return m_instructions.size(); }
 
uint32_t InstructionList::GetMaxOpcocdeByteSize() const {
  uint32_t max_inst_size = 0;
  collection::const_iterator pos, end;
  for (pos = m_instructions.begin(), end = m_instructions.end(); pos != end;
       ++pos) {
    uint32_t inst_size = (*pos)->GetOpcode().GetByteSize();
    if (max_inst_size < inst_size)
      max_inst_size = inst_size;
  }
  return max_inst_size;
}
 
size_t InstructionList::GetTotalByteSize() const {
  size_t total_byte_size = 0;
  collection::const_iterator pos, end;
  for (pos = m_instructions.begin(), end = m_instructions.end(); pos != end;
       ++pos) {
    total_byte_size += (*pos)->GetOpcode().GetByteSize();
  }
  return total_byte_size;
}
 
InstructionSP InstructionList::GetInstructionAtIndex(size_t idx) const {
  InstructionSP inst_sp;
  if (idx < m_instructions.size())
    inst_sp = m_instructions[idx];
  return inst_sp;
}
 
InstructionSP InstructionList::GetInstructionAtAddress(const Address &address) {
  uint32_t index = GetIndexOfInstructionAtAddress(address);
  if (index != UINT32_MAX)
    return GetInstructionAtIndex(index);
  return nullptr;
}
 
void InstructionList::Dump(Stream *s, bool show_address, bool show_bytes,
                           bool show_control_flow_kind,
                           const ExecutionContext *exe_ctx) {
  const uint32_t max_opcode_byte_size = GetMaxOpcocdeByteSize();
  collection::const_iterator pos, begin, end;
 
  const FormatEntity::Entry *disassembly_format = nullptr;
  FormatEntity::Entry format;
  if (exe_ctx && exe_ctx->HasTargetScope()) {
    format = exe_ctx->GetTargetRef().GetDebugger().GetDisassemblyFormat();
    disassembly_format = &format;
  } else {
    FormatEntity::Parse("${addr}: ", format);
    disassembly_format = &format;
  }
 
  for (begin = m_instructions.begin(), end = m_instructions.end(), pos = begin;
       pos != end; ++pos) {
    if (pos != begin)
      s->EOL();
    (*pos)->Dump(s, max_opcode_byte_size, show_address, show_bytes,
                 show_control_flow_kind, exe_ctx, nullptr, nullptr,
                 disassembly_format, 0);
  }
}
 
void InstructionList::Clear() { m_instructions.clear(); }
 
void InstructionList::Append(lldb::InstructionSP &inst_sp) {
  if (inst_sp)
    m_instructions.push_back(inst_sp);
}
 
uint32_t InstructionList::GetIndexOfNextBranchInstruction(
    uint32_t start, bool ignore_calls, bool *found_calls) const {
  size_t num_instructions = m_instructions.size();
 
  uint32_t next_branch = UINT32_MAX;
 
  if (found_calls)
    *found_calls = false;
  for (size_t i = start; i < num_instructions; i++) {
    if (m_instructions[i]->DoesBranch()) {
      if (ignore_calls && m_instructions[i]->IsCall()) {
        if (found_calls)
          *found_calls = true;
        continue;
      }
      next_branch = i;
      break;
    }
  }
 
  return next_branch;
}
 
uint32_t
InstructionList::GetIndexOfInstructionAtAddress(const Address &address) {
  size_t num_instructions = m_instructions.size();
  uint32_t index = UINT32_MAX;
  for (size_t i = 0; i < num_instructions; i++) {
    if (m_instructions[i]->GetAddress() == address) {
      index = i;
      break;
    }
  }
  return index;
}
 
uint32_t
InstructionList::GetIndexOfInstructionAtLoadAddress(lldb::addr_t load_addr,
                                                    Target &target) {
  Address address;
  address.SetLoadAddress(load_addr, &target);
  return GetIndexOfInstructionAtAddress(address);
}
 
size_t Disassembler::AppendInstructions(Target &target, Address start,
                                        Limit limit, Stream *error_strm_ptr,
                                        bool force_live_memory) {
  if (!start.IsValid())
    return 0;
 
  start = ResolveAddress(target, start);
 
  // Don't decode a non-instruction function header.
  if (Architecture *arch = target.GetArchitecturePlugin()) {
    const Address first_insn = arch->SkipFunctionHeader(start);
    if (first_insn.GetFileAddress() != start.GetFileAddress()) {
      const addr_t skip = first_insn.GetFileAddress() - start.GetFileAddress();
      start = first_insn;
      // The skipped header bytes still count against a byte limit.
      if (limit.kind == Limit::Bytes && limit.value > skip)
        limit.value -= skip;
    }
  }
 
  addr_t byte_size = limit.value;
  if (limit.kind == Limit::Instructions)
    byte_size *= m_arch.GetMaximumOpcodeByteSize();
  auto data_sp = std::make_shared<DataBufferHeap>(byte_size, '\0');
 
  Status error;
  lldb::addr_t load_addr = LLDB_INVALID_ADDRESS;
  const size_t bytes_read =
      target.ReadMemory(start, data_sp->GetBytes(), data_sp->GetByteSize(),
                        error, force_live_memory, &load_addr);
  const bool data_from_file = load_addr == LLDB_INVALID_ADDRESS;
 
  if (bytes_read == 0) {
    if (error_strm_ptr) {
      if (const char *error_cstr = error.AsCString(nullptr))
        error_strm_ptr->Printf("error: %s\n", error_cstr);
    }
    return 0;
  }
 
  if (bytes_read != data_sp->GetByteSize())
    data_sp->SetByteSize(bytes_read);
  DataExtractor data(data_sp, m_arch.GetByteOrder(),
                     m_arch.GetAddressByteSize());
  return DecodeInstructions(start, data, 0,
                            limit.kind == Limit::Instructions ? limit.value
                                                              : UINT32_MAX,
                            /*append=*/true, data_from_file);
}
 
// Disassembler copy constructor
Disassembler::Disassembler(const ArchSpec &arch, const char *flavor)
    : m_arch(arch), m_instruction_list(), m_flavor() {
  if (flavor == nullptr)
    m_flavor.assign("default");
  else
    m_flavor.assign(flavor);
 
  // If this is an arm variant that can only include thumb (T16, T32)
  // instructions, force the arch triple to be "thumbv.." instead of "armv..."
  if (arch.IsAlwaysThumbInstructions()) {
    std::string thumb_arch_name(arch.GetTriple().getArchName().str());
    // Replace "arm" with "thumb" so we get all thumb variants correct
    if (thumb_arch_name.size() > 3) {
      thumb_arch_name.erase(0, 3);
      thumb_arch_name.insert(0, "thumb");
    }
    m_arch.SetTriple(thumb_arch_name.c_str());
  }
}
 
Disassembler::~Disassembler() = default;
 
InstructionList &Disassembler::GetInstructionList() {
  return m_instruction_list;
}
 
const InstructionList &Disassembler::GetInstructionList() const {
  return m_instruction_list;
}
 
// Class PseudoInstruction
 
PseudoInstruction::PseudoInstruction()
    : Instruction(Address(), AddressClass::eUnknown), m_description() {}
 
PseudoInstruction::~PseudoInstruction() = default;
 
bool PseudoInstruction::DoesBranch() {
  // This is NOT a valid question for a pseudo instruction.
  return false;
}
 
bool PseudoInstruction::IsBarrier() {
  // This is NOT a valid question for a pseudo instruction.
  return false;
}
 
bool PseudoInstruction::HasDelaySlot() {
  // This is NOT a valid question for a pseudo instruction.
  return false;
}
 
bool PseudoInstruction::IsLoad() { return false; }
 
bool PseudoInstruction::IsAuthenticated() { return false; }
 
size_t PseudoInstruction::Decode(const lldb_private::Disassembler &disassembler,
                                 const lldb_private::DataExtractor &data,
                                 lldb::offset_t data_offset) {
  return m_opcode.GetByteSize();
}
 
void PseudoInstruction::SetOpcode(size_t opcode_size, void *opcode_data) {
  if (!opcode_data)
    return;
 
  switch (opcode_size) {
  case 8: {
    uint8_t value8 = *((uint8_t *)opcode_data);
    m_opcode.SetOpcode8(value8, eByteOrderInvalid);
    break;
  }
  case 16: {
    uint16_t value16 = *((uint16_t *)opcode_data);
    m_opcode.SetOpcode16(value16, eByteOrderInvalid);
    break;
  }
  case 32: {
    uint32_t value32 = *((uint32_t *)opcode_data);
    m_opcode.SetOpcode32(value32, eByteOrderInvalid);
    break;
  }
  case 64: {
    uint64_t value64 = *((uint64_t *)opcode_data);
    m_opcode.SetOpcode64(value64, eByteOrderInvalid);
    break;
  }
  default:
    break;
  }
}
 
void PseudoInstruction::SetDescription(llvm::StringRef description) {
  m_description = std::string(description);
}
 
Instruction::Operand Instruction::Operand::BuildRegister(ConstString &r) {
  Operand ret;
  ret.m_type = Type::Register;
  ret.m_register = r;
  return ret;
}
 
Instruction::Operand Instruction::Operand::BuildImmediate(lldb::addr_t imm,
                                                          bool neg) {
  Operand ret;
  ret.m_type = Type::Immediate;
  ret.m_immediate = imm;
  ret.m_negative = neg;
  return ret;
}
 
Instruction::Operand Instruction::Operand::BuildImmediate(int64_t imm) {
  Operand ret;
  ret.m_type = Type::Immediate;
  if (imm < 0) {
    ret.m_immediate = -imm;
    ret.m_negative = true;
  } else {
    ret.m_immediate = imm;
    ret.m_negative = false;
  }
  return ret;
}
 
Instruction::Operand
Instruction::Operand::BuildDereference(const Operand &ref) {
  Operand ret;
  ret.m_type = Type::Dereference;
  ret.m_children = {ref};
  return ret;
}
 
Instruction::Operand Instruction::Operand::BuildSum(const Operand &lhs,
                                                    const Operand &rhs) {
  Operand ret;
  ret.m_type = Type::Sum;
  ret.m_children = {lhs, rhs};
  return ret;
}
 
Instruction::Operand Instruction::Operand::BuildProduct(const Operand &lhs,
                                                        const Operand &rhs) {
  Operand ret;
  ret.m_type = Type::Product;
  ret.m_children = {lhs, rhs};
  return ret;
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::MatchBinaryOp(
    std::function<bool(const Instruction::Operand &)> base,
    std::function<bool(const Instruction::Operand &)> left,
    std::function<bool(const Instruction::Operand &)> right) {
  return [base, left, right](const Instruction::Operand &op) -> bool {
    return (base(op) && op.m_children.size() == 2 &&
            ((left(op.m_children[0]) && right(op.m_children[1])) ||
             (left(op.m_children[1]) && right(op.m_children[0]))));
  };
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::MatchUnaryOp(
    std::function<bool(const Instruction::Operand &)> base,
    std::function<bool(const Instruction::Operand &)> child) {
  return [base, child](const Instruction::Operand &op) -> bool {
    return (base(op) && op.m_children.size() == 1 && child(op.m_children[0]));
  };
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::MatchRegOp(const RegisterInfo &info) {
  return [&info](const Instruction::Operand &op) {
    return (op.m_type == Instruction::Operand::Type::Register &&
            (op.m_register == ConstString(info.name) ||
             op.m_register == ConstString(info.alt_name)));
  };
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::FetchRegOp(ConstString &reg) {
  return [&reg](const Instruction::Operand &op) {
    if (op.m_type != Instruction::Operand::Type::Register) {
      return false;
    }
    reg = op.m_register;
    return true;
  };
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::MatchImmOp(int64_t imm) {
  return [imm](const Instruction::Operand &op) {
    return (op.m_type == Instruction::Operand::Type::Immediate &&
            ((op.m_negative && op.m_immediate == (uint64_t)-imm) ||
             (!op.m_negative && op.m_immediate == (uint64_t)imm)));
  };
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::FetchImmOp(int64_t &imm) {
  return [&imm](const Instruction::Operand &op) {
    if (op.m_type != Instruction::Operand::Type::Immediate) {
      return false;
    }
    if (op.m_negative) {
      imm = -((int64_t)op.m_immediate);
    } else {
      imm = ((int64_t)op.m_immediate);
    }
    return true;
  };
}
 
std::function<bool(const Instruction::Operand &)>
lldb_private::OperandMatchers::MatchOpType(Instruction::Operand::Type type) {
  return [type](const Instruction::Operand &op) { return op.m_type == type; };
}