Disassembler.h

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//===-- Disassembler.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_CORE_DISASSEMBLER_H
#define LLDB_CORE_DISASSEMBLER_H
 
#include "lldb/Core/Address.h"
#include "lldb/Core/EmulateInstruction.h"
#include "lldb/Core/FormatEntity.h"
#include "lldb/Core/Opcode.h"
#include "lldb/Core/PluginInterface.h"
#include "lldb/Interpreter/OptionValue.h"
#include "lldb/Symbol/LineEntry.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/FileSpec.h"
#include "lldb/Utility/StructuredData.h"
#include "lldb/lldb-defines.h"
#include "lldb/lldb-forward.h"
#include "lldb/lldb-private-enumerations.h"
#include "lldb/lldb-types.h"
 
#include "llvm/ADT/StringRef.h"
 
#include <functional>
#include <map>
#include <memory>
#include <set>
#include <string>
#include <vector>
 
#include <cstddef>
#include <cstdint>
#include <cstdio>
 
namespace llvm {
template <typename T> class SmallVectorImpl;
}
 
namespace lldb_private {
class AddressRange;
class DataExtractor;
class Debugger;
class Disassembler;
class Module;
class StackFrame;
class Stream;
class SymbolContext;
class SymbolContextList;
class Target;
struct RegisterInfo;
 
class Instruction {
public:
  Instruction(const Address &address,
              AddressClass addr_class = AddressClass::eInvalid);
 
  virtual ~Instruction();
 
  const Address &GetAddress() const { return m_address; }
 
  const char *GetMnemonic(const ExecutionContext *exe_ctx,
                          bool markup = false) {
    CalculateMnemonicOperandsAndCommentIfNeeded(exe_ctx);
    return markup ? m_markup_opcode_name.c_str() : m_opcode_name.c_str();
  }
 
  const char *GetOperands(const ExecutionContext *exe_ctx,
                          bool markup = false) {
    CalculateMnemonicOperandsAndCommentIfNeeded(exe_ctx);
    return markup ? m_markup_mnemonics.c_str() : m_mnemonics.c_str();
  }
 
  const char *GetComment(const ExecutionContext *exe_ctx) {
    CalculateMnemonicOperandsAndCommentIfNeeded(exe_ctx);
    return m_comment.c_str();
  }
 
  /// \return
  ///    The control flow kind of this instruction, or
  ///    eInstructionControlFlowKindUnknown if the instruction
  ///    can't be classified.
  virtual lldb::InstructionControlFlowKind
  GetControlFlowKind(const ExecutionContext *exe_ctx) {
    return lldb::eInstructionControlFlowKindUnknown;
  }
 
  virtual void
  CalculateMnemonicOperandsAndComment(const ExecutionContext *exe_ctx) = 0;
 
  AddressClass GetAddressClass();
 
  void SetAddress(const Address &addr) {
    // Invalidate the address class to lazily discover it if we need to.
    m_address_class = AddressClass::eInvalid;
    m_address = addr;
  }
 
  /// Dump the text representation of this Instruction to a Stream
  ///
  /// Print the (optional) address, (optional) bytes, opcode,
  /// operands, and instruction comments to a stream.
  ///
  /// \param[in] s
  ///     The Stream to add the text to.
  ///
  /// \param[in] show_address
  ///     Whether the address (using disassembly_addr_format_spec formatting)
  ///     should be printed.
  ///
  /// \param[in] show_bytes
  ///     Whether the bytes of the assembly instruction should be printed.
  ///
  /// \param[in] show_control_flow_kind
  ///     Whether the control flow kind of the instruction should be printed.
  ///
  /// \param[in] max_opcode_byte_size
  ///     The size (in bytes) of the largest instruction in the list that
  ///     we are printing (for text justification/alignment purposes)
  ///     Only needed if show_bytes is true.
  ///
  /// \param[in] exe_ctx
  ///     The current execution context, if available.  May be used in
  ///     the assembling of the operands+comments for this instruction.
  ///     Pass NULL if not applicable.
  ///
  /// \param[in] sym_ctx
  ///     The SymbolContext for this instruction.
  ///     Pass NULL if not available/computed.
  ///     Only needed if show_address is true.
  ///
  /// \param[in] prev_sym_ctx
  ///     The SymbolContext for the previous instruction.  Depending on
  ///     the disassembly address format specification, a change in
  ///     Symbol / Function may mean that a line is printed with the new
  ///     symbol/function name.
  ///     Pass NULL if unavailable, or if this is the first instruction of
  ///     the InstructionList.
  ///     Only needed if show_address is true.
  ///
  /// \param[in] disassembly_addr_format
  ///     The format specification for how addresses are printed.
  ///     Only needed if show_address is true.
  ///
  /// \param[in] max_address_text_size
  ///     The length of the longest address string at the start of the
  ///     disassembly line that will be printed (the
  ///     Debugger::FormatDisassemblerAddress() string)
  ///     so this method can properly align the instruction opcodes.
  ///     May be 0 to indicate no indentation/alignment of the opcodes.
  virtual void Dump(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);
 
  virtual bool DoesBranch() = 0;
 
  virtual bool HasDelaySlot();
 
  virtual bool IsLoad() = 0;
 
  virtual bool IsBarrier() = 0;
 
  virtual bool IsAuthenticated() = 0;
 
  bool CanSetBreakpoint();
 
  virtual size_t Decode(const Disassembler &disassembler,
                        const DataExtractor &data,
                        lldb::offset_t data_offset) = 0;
 
  virtual void SetDescription(llvm::StringRef) {
  } // May be overridden in sub-classes that have descriptions.
 
  lldb::OptionValueSP ReadArray(FILE *in_file, Stream &out_stream,
                                OptionValue::Type data_type);
 
  lldb::OptionValueSP ReadDictionary(FILE *in_file, Stream &out_stream);
 
  bool DumpEmulation(const ArchSpec &arch);
 
  virtual bool TestEmulation(Stream &stream, const char *test_file_name);
 
  bool Emulate(const ArchSpec &arch, uint32_t evaluate_options, void *baton,
               EmulateInstruction::ReadMemoryCallback read_mem_callback,
               EmulateInstruction::WriteMemoryCallback write_mem_calback,
               EmulateInstruction::ReadRegisterCallback read_reg_callback,
               EmulateInstruction::WriteRegisterCallback write_reg_callback);
 
  const Opcode &GetOpcode() const { return m_opcode; }
 
  uint32_t GetData(DataExtractor &data);
 
  struct Operand {
    enum class Type {
      Invalid = 0,
      Register,
      Immediate,
      Dereference,
      Sum,
      Product
    } m_type = Type::Invalid;
    std::vector<Operand> m_children;
    lldb::addr_t m_immediate = 0;
    std::string m_register;
    bool m_negative = false;
    bool m_clobbered = false;
 
    bool IsValid() { return m_type != Type::Invalid; }
 
    static Operand BuildRegister(llvm::StringRef r);
    static Operand BuildImmediate(lldb::addr_t imm, bool neg);
    static Operand BuildImmediate(int64_t imm);
    static Operand BuildDereference(const Operand &ref);
    static Operand BuildSum(const Operand &lhs, const Operand &rhs);
    static Operand BuildProduct(const Operand &lhs, const Operand &rhs);
  };
 
  virtual bool ParseOperands(llvm::SmallVectorImpl<Operand> &operands) {
    return false;
  }
 
  virtual bool IsCall() { return false; }
 
  static const char *GetNameForInstructionControlFlowKind(
      lldb::InstructionControlFlowKind instruction_control_flow_kind);
 
  /// Get variable annotations for this instruction as structured data.
  /// Returns an array of dictionaries to be used in SBInstruction class.
  StructuredData::ArraySP GetVariableAnnotations();
 
protected:
  Address m_address; // The section offset address of this instruction
                     // We include an address class in the Instruction class to
                     // allow the instruction specify the
                     // AddressClass::eCodeAlternateISA (currently used for
                     // thumb), and also to specify data (AddressClass::eData).
                     // The usual value will be AddressClass::eCode, but often
                     // when disassembling memory, you might run into data.
                     // This can help us to disassemble appropriately.
private:
  AddressClass m_address_class; // Use GetAddressClass () accessor function!
 
protected:
  Opcode m_opcode; // The opcode for this instruction
  std::string m_opcode_name;
  std::string m_markup_opcode_name;
  std::string m_mnemonics;
  std::string m_markup_mnemonics;
  std::string m_comment;
  bool m_calculated_strings;
 
  void
  CalculateMnemonicOperandsAndCommentIfNeeded(const ExecutionContext *exe_ctx) {
    if (!m_calculated_strings) {
      m_calculated_strings = true;
      CalculateMnemonicOperandsAndComment(exe_ctx);
    }
  }
};
 
namespace OperandMatchers {
std::function<bool(const Instruction::Operand &)>
MatchBinaryOp(std::function<bool(const Instruction::Operand &)> base,
              std::function<bool(const Instruction::Operand &)> left,
              std::function<bool(const Instruction::Operand &)> right);
 
std::function<bool(const Instruction::Operand &)>
MatchUnaryOp(std::function<bool(const Instruction::Operand &)> base,
             std::function<bool(const Instruction::Operand &)> child);
 
std::function<bool(const Instruction::Operand &)>
MatchRegOp(const RegisterInfo &info);
 
std::function<bool(const Instruction::Operand &)> FetchRegOp(std::string &reg);
 
std::function<bool(const Instruction::Operand &)> MatchImmOp(int64_t imm);
 
std::function<bool(const Instruction::Operand &)> FetchImmOp(int64_t &imm);
 
std::function<bool(const Instruction::Operand &)>
MatchOpType(Instruction::Operand::Type type);
} // namespace OperandMatchers
 
class InstructionList {
public:
  InstructionList();
  ~InstructionList();
 
  size_t GetSize() const;
 
  size_t GetTotalByteSize() const;
 
  uint32_t GetMaxOpcocdeByteSize() const;
 
  lldb::InstructionSP GetInstructionAtIndex(size_t idx) const;
 
  llvm::ArrayRef<lldb::InstructionSP> Instructions() const {
    return m_instructions;
  }
 
  /// Get the instruction at the given address.
  ///
  /// \return
  ///    A valid \a InstructionSP if the address could be found, or null
  ///    otherwise.
  lldb::InstructionSP GetInstructionAtAddress(const Address &addr);
 
  //------------------------------------------------------------------
  /// Get the index of the next branch instruction.
  ///
  /// Given a list of instructions, find the next branch instruction
  /// in the list by returning an index.
  ///
  /// @param[in] start
  ///     The instruction index of the first instruction to check.
  ///
  /// @param[in] ignore_calls
  ///     It true, then fine the first branch instruction that isn't
  ///     a function call (a branch that calls and returns to the next
  ///     instruction). If false, find the instruction index of any
  ///     branch in the list.
  ///
  /// @param[out] found_calls
  ///     If non-null, this will be set to true if any calls were found in
  ///     extending the range.
  ///
  /// @return
  ///     The instruction index of the first branch that is at or past
  ///     \a start. Returns UINT32_MAX if no matching branches are
  ///     found.
  //------------------------------------------------------------------
  uint32_t GetIndexOfNextBranchInstruction(uint32_t start, bool ignore_calls,
                                           bool *found_calls) const;
 
  uint32_t GetIndexOfInstructionAtLoadAddress(lldb::addr_t load_addr,
                                              Target &target);
 
  uint32_t GetIndexOfInstructionAtAddress(const Address &addr);
 
  void Clear();
 
  void Append(lldb::InstructionSP &inst_sp);
 
  void Dump(Stream *s, bool show_address, bool show_bytes,
            bool show_control_flow_kind, const ExecutionContext *exe_ctx);
 
private:
  typedef std::vector<lldb::InstructionSP> collection;
  typedef collection::iterator iterator;
  typedef collection::const_iterator const_iterator;
 
  collection m_instructions;
};
 
class PseudoInstruction : public Instruction {
public:
  PseudoInstruction();
 
  ~PseudoInstruction() override;
 
  bool DoesBranch() override;
 
  bool HasDelaySlot() override;
 
  bool IsLoad() override;
 
  bool IsBarrier() override;
 
  bool IsAuthenticated() override;
 
  void CalculateMnemonicOperandsAndComment(
      const ExecutionContext *exe_ctx) override {
    // TODO: fill this in and put opcode name into Instruction::m_opcode_name,
    // mnemonic into Instruction::m_mnemonics, and any comment into
    // Instruction::m_comment
  }
 
  size_t Decode(const Disassembler &disassembler, const DataExtractor &data,
                lldb::offset_t data_offset) override;
 
  void SetOpcode(size_t opcode_size, void *opcode_data);
 
  void SetDescription(llvm::StringRef description) override;
 
protected:
  std::string m_description;
 
  PseudoInstruction(const PseudoInstruction &) = delete;
  const PseudoInstruction &operator=(const PseudoInstruction &) = delete;
};
 
class Disassembler : public std::enable_shared_from_this<Disassembler>,
                     public PluginInterface {
public:
  enum {
    eOptionNone = 0u,
    eOptionShowBytes = (1u << 0),
    eOptionRawOuput = (1u << 1),
    eOptionMarkPCSourceLine = (1u << 2), // Mark the source line that contains
                                         // the current PC (mixed mode only)
    eOptionMarkPCAddress =
        (1u << 3), // Mark the disassembly line the contains the PC
    eOptionShowControlFlowKind = (1u << 4),
    eOptionVariableAnnotations = (1u << 5),
  };
 
  enum HexImmediateStyle {
    eHexStyleC,
    eHexStyleAsm,
  };
 
  // FindPlugin should be lax about the flavor string (it is too annoying to
  // have various internal uses of the disassembler fail because the global
  // flavor string gets set wrong. Instead, if you get a flavor string you
  // don't understand, use the default.  Folks who care to check can use the
  // FlavorValidForArchSpec method on the disassembler they got back.
  static lldb::DisassemblerSP FindPlugin(const ArchSpec &arch,
                                         const char *flavor, const char *cpu,
                                         const char *features,
                                         const char *plugin_name);
 
  // This version will use the value in the Target settings if flavor is NULL;
  static lldb::DisassemblerSP
  FindPluginForTarget(const Target &target, const ArchSpec &arch,
                      const char *flavor, const char *cpu, const char *features,
                      const char *plugin_name);
 
  struct Limit {
    enum { Bytes, Instructions } kind;
    lldb::addr_t value;
  };
 
  static lldb::DisassemblerSP
  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 = false);
 
  static lldb::DisassemblerSP
  DisassembleBytes(const ArchSpec &arch, const char *plugin_name,
                   const char *flavor, const char *cpu, const char *features,
                   const Address &start, const void *bytes, size_t length,
                   uint32_t max_num_instructions, bool data_from_file);
 
  static bool 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 &start,
                          Limit limit, bool mixed_source_and_assembly,
                          uint32_t num_mixed_context_lines, uint32_t options,
                          Stream &strm);
 
  static bool Disassemble(Debugger &debugger, const ArchSpec &arch,
                          StackFrame &frame, Stream &strm);
 
  // Constructors and Destructors
  Disassembler(const ArchSpec &arch, const char *flavor);
  ~Disassembler() override;
 
  void 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);
 
  size_t ParseInstructions(Target &target, Address address, Limit limit,
                           Stream *error_strm_ptr,
                           bool force_live_memory = false) {
    m_instruction_list.Clear();
    return AppendInstructions(target, address, limit, error_strm_ptr,
                              force_live_memory);
  }
 
  virtual size_t DecodeInstructions(const Address &base_addr,
                                    const DataExtractor &data,
                                    lldb::offset_t data_offset,
                                    size_t num_instructions, bool append,
                                    bool data_from_file) = 0;
 
  InstructionList &GetInstructionList();
 
  const InstructionList &GetInstructionList() const;
 
  const ArchSpec &GetArchitecture() const { return m_arch; }
 
  const char *GetFlavor() const { return m_flavor.c_str(); }
 
  virtual bool FlavorValidForArchSpec(const lldb_private::ArchSpec &arch,
                                      const char *flavor) = 0;
 
protected:
  size_t AppendInstructions(Target &target, Address address, Limit limit,
                            Stream *error_strm_ptr, bool force_live_memory);
 
  // SourceLine and SourceLinesToDisplay structures are only used in the mixed
  // source and assembly display methods internal to this class.
 
  struct SourceLine {
    FileSpec file;
    uint32_t line = LLDB_INVALID_LINE_NUMBER;
    uint32_t column = 0;
 
    SourceLine() = default;
 
    bool operator==(const SourceLine &rhs) const {
      return file == rhs.file && line == rhs.line && rhs.column == column;
    }
 
    bool operator!=(const SourceLine &rhs) const {
      return file != rhs.file || line != rhs.line || column != rhs.column;
    }
 
    bool IsValid() const { return line != LLDB_INVALID_LINE_NUMBER; }
  };
 
  struct SourceLinesToDisplay {
    std::vector<SourceLine> lines;
 
    // index of the "current" source line, if we want to highlight that when
    // displaying the source lines.  (as opposed to the surrounding source
    // lines provided to give context)
    size_t current_source_line = -1;
 
    // Whether to print a blank line at the end of the source lines.
    bool print_source_context_end_eol = true;
 
    SourceLinesToDisplay() = default;
  };
 
  // Get the function's declaration line number, hopefully a line number
  // earlier than the opening curly brace at the start of the function body.
  static SourceLine GetFunctionDeclLineEntry(const SymbolContext &sc);
 
  // Add the provided SourceLine to the map of filenames-to-source-lines-seen.
  static void AddLineToSourceLineTables(
      SourceLine &line,
      std::map<FileSpec, std::set<uint32_t>> &source_lines_seen);
 
  // Given a source line, determine if we should print it when we're doing
  // mixed source & assembly output. We're currently using the
  // target.process.thread.step-avoid-regexp setting (which is used for
  // stepping over inlined STL functions by default) to determine what source
  // lines to avoid showing.
  //
  // Returns true if this source line should be elided (if the source line
  // should not be displayed).
  static bool
  ElideMixedSourceAndDisassemblyLine(const ExecutionContext &exe_ctx,
                                     const SymbolContext &sc, SourceLine &line);
 
  static bool
  ElideMixedSourceAndDisassemblyLine(const ExecutionContext &exe_ctx,
                                     const SymbolContext &sc, LineEntry &line) {
    SourceLine sl;
    sl.file = line.GetFile();
    sl.line = line.line;
    sl.column = line.column;
    return ElideMixedSourceAndDisassemblyLine(exe_ctx, sc, sl);
  };
 
  // Classes that inherit from Disassembler can see and modify these
  ArchSpec m_arch;
  InstructionList m_instruction_list;
  std::string m_flavor;
 
private:
  // For Disassembler only
  Disassembler(const Disassembler &) = delete;
  const Disassembler &operator=(const Disassembler &) = delete;
};
 
/// Structured data for a single variable annotation.
struct VariableAnnotation {
  std::string variable_name;
  /// Location description (e.g., "r15", "undef", "const_0").
  std::string location_description;
  /// Whether variable is live at this instruction.
  bool is_live;
  /// Register numbering scheme for location interpretation.
  lldb::RegisterKind register_kind;
  /// Where this annotation is valid.
  std::optional<lldb_private::AddressRange> address_range;
  /// Source file where variable was declared.
  std::optional<std::string> decl_file;
  /// Line number where variable was declared.
  std::optional<uint32_t> decl_line;
  /// Variable's type name.
  std::optional<std::string> type_name;
};
 
/// Tracks live variable annotations across instructions and produces
/// per-instruction "events" like `name = RDI` or `name = <undef>`.
class VariableAnnotator {
 
  // Live state from the previous instruction, keyed by Variable::GetID().
  llvm::DenseMap<lldb::user_id_t, VariableAnnotation> m_live_vars;
 
public:
  /// Compute annotation strings for a single instruction and update
  /// `m_live_vars`. Returns only the events that should be printed *at this
  /// instruction*.
  std::vector<std::string> Annotate(Instruction &inst);
 
  /// Returns structured data for all variables relevant at this instruction.
  std::vector<VariableAnnotation> AnnotateStructured(Instruction &inst);
};
 
} // namespace lldb_private
 
#endif // LLDB_CORE_DISASSEMBLER_H