llvm/tools/llvm-objdump/SourcePrinter.h

//===-- SourcePrinter.h -  source interleaving utilities --------*- 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 LLVM_TOOLS_LLVM_OBJDUMP_SOURCEPRINTER_H
#define LLVM_TOOLS_LLVM_OBJDUMP_SOURCEPRINTER_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/Symbolize/Symbolize.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/FormattedStream.h"
#include <set>
#include <vector>

namespace llvm {
namespace objdump {

/// Base class for representing the location of a source-level variable or
/// an inlined function.
class LiveElement {
protected:
  const char *Name;
  DWARFUnit *Unit;
  const DWARFDie FuncDie;

public:
  LiveElement(const char *Name, DWARFUnit *Unit, const DWARFDie FuncDie)
      : Name(Name), Unit(Unit), FuncDie(FuncDie) {}

  virtual ~LiveElement() = default;
  const char *getName() const { return Name; }

  virtual bool liveAtAddress(object::SectionedAddress Addr) const = 0;
  virtual void print(raw_ostream &OS, const MCRegisterInfo &MRI) const = 0;
  virtual void dump(raw_ostream &OS) const = 0;
  virtual void printElementLine(raw_ostream &OS,
                                object::SectionedAddress Address,
                                bool IsEnd) const {}
};

class InlinedFunction : public LiveElement {
private:
  DWARFDie InlinedFuncDie;
  DWARFAddressRange Range;

public:
  InlinedFunction(const char *FunctionName, DWARFUnit *Unit,
                  const DWARFDie FuncDie, const DWARFDie InlinedFuncDie,
                  DWARFAddressRange &Range)
      : LiveElement(FunctionName, Unit, FuncDie),
        InlinedFuncDie(InlinedFuncDie), Range(Range) {}

  bool liveAtAddress(object::SectionedAddress Addr) const override;
  void print(raw_ostream &OS, const MCRegisterInfo &MRI) const override;
  void dump(raw_ostream &OS) const override;
  void printElementLine(raw_ostream &OS, object::SectionedAddress Address,
                        bool IsEnd) const override;
};

/// Stores a single expression representing the location of a source-level
/// variable, along with the PC range for which that expression is valid.
class LiveVariable : public LiveElement {
private:
  DWARFLocationExpression LocExpr;

public:
  LiveVariable(const DWARFLocationExpression &LocExpr, const char *VarName,
               DWARFUnit *Unit, const DWARFDie FuncDie)
      : LiveElement(VarName, Unit, FuncDie), LocExpr(LocExpr) {}

  bool liveAtAddress(object::SectionedAddress Addr) const override;
  void print(raw_ostream &OS, const MCRegisterInfo &MRI) const override;
  void dump(raw_ostream &OS) const override;
  const DWARFLocationExpression &getLocExpr() const { return LocExpr; }
};

/// Helper class for printing source locations for variables and inlined
/// subroutines alongside disassembly.
class LiveElementPrinter {
  // Information we want to track about one column in which we are printing an
  // element live range.
  struct Column {
    unsigned ElementIdx = NullElementIdx;
    bool LiveIn = false;
    bool LiveOut = false;
    bool MustDrawLabel = false;

    bool isActive() const { return ElementIdx != NullElementIdx; }

    static constexpr unsigned NullElementIdx =
        std::numeric_limits<unsigned>::max();

    // Clear the column's data.
    void clear() {
      ElementIdx = NullElementIdx;
      LiveIn = false;
      LiveOut = false;
      MustDrawLabel = false;
    }
  };

  // Vector that owns all LiveElement objects for memory management.
  std::vector<std::unique_ptr<LiveElement>> LiveElements;
  // Map for fast lookup of live elements by their starting address (LowPC).
  llvm::MapVector<uint64_t, std::vector<LiveElement *>> LiveElementsByAddress;
  // Map for fast lookup of live elements by their ending address (HighPC).
  llvm::MapVector<uint64_t, std::vector<LiveElement *>>
      LiveElementsByEndAddress;
  // Map from a LiveElement pointer to its index in the LiveElements vector.
  llvm::DenseMap<LiveElement *, unsigned> ElementPtrToIndex;
  // Map from a live element index to column index for efficient lookup.
  llvm::DenseMap<unsigned, unsigned> ElementToColumn;
  // Vector of columns currently used for printing live ranges.
  std::vector<Column> ActiveCols;
  // Set of available column indices kept sorted for efficient reuse.
  std::set<unsigned> FreeCols;
  // Vector of available column indices that can be reused.
  std::vector<unsigned> ColumnsToFreeNextCycle;

  const MCRegisterInfo &MRI;
  const MCSubtargetInfo &STI;

  void registerNewVariable();

  void addInlinedFunction(DWARFDie FuncDie, DWARFDie InlinedFuncDie);
  void addVariable(DWARFDie FuncDie, DWARFDie VarDie);

  void addFunction(DWARFDie D);

  // Get the column number (in characters) at which the first live element
  // line should be printed.
  unsigned getIndentLevel() const;

  // Indent to the first live-range column to the right of the currently
  // printed line, and return the index of that column.
  // TODO: formatted_raw_ostream uses "column" to mean a number of characters
  // since the last \n, and we use it to mean the number of slots in which we
  // put live element lines. Pick a less overloaded word.
  unsigned moveToFirstVarColumn(formatted_raw_ostream &OS);

  // Get an existing column for a live element, or find a free one.
  unsigned getOrCreateColumn(unsigned ElementIdx);

  // Free a column when its element is no longer live.
  void freeColumn(unsigned ColIdx);

  // Returns the indices of all currently active elements, sorted by their DWARF
  // discovery order.
  std::vector<unsigned> getSortedActiveElementIndices() const;

public:
  LiveElementPrinter(const MCRegisterInfo &MRI, const MCSubtargetInfo &STI)
      : MRI(MRI), STI(STI) {}

  void dump() const;

  void addCompileUnit(DWARFDie D);

  /// Update to match the state of the instruction between ThisAddr and
  /// NextAddr. In the common case, any live range active at ThisAddr is
  /// live-in to the instruction, and any live range active at NextAddr is
  /// live-out of the instruction. If IncludeDefinedVars is false, then live
  /// ranges starting at NextAddr will be ignored.
  void update(object::SectionedAddress ThisAddr,
              object::SectionedAddress NextAddr, bool IncludeDefinedVars);

  enum class LineChar {
    RangeStart,
    RangeMid,
    RangeEnd,
    LabelVert,
    LabelCornerNew,
    LabelCornerActive,
    LabelHoriz,
  };
  const char *getLineChar(LineChar C) const;

  /// Print live ranges to the right of an existing line. This assumes the
  /// line is not an instruction, so doesn't start or end any live ranges, so
  /// we only need to print active ranges or empty columns. If AfterInst is
  /// true, this is being printed after the last instruction fed to update(),
  /// otherwise this is being printed before it.
  void printAfterOtherLine(formatted_raw_ostream &OS, bool AfterInst);

  /// Print any live element range info needed to the right of a
  /// non-instruction line of disassembly. This is where we print the variable
  /// names and expressions, with thin line-drawing characters connecting them
  /// to the live range which starts at the next instruction. If MustPrint is
  /// true, we have to print at least one line (with the continuation of any
  /// already-active live ranges) because something has already been printed
  /// earlier on this line.
  void printBetweenInsts(formatted_raw_ostream &OS, bool MustPrint);

  /// Print the live element ranges to the right of a disassembled instruction.
  void printAfterInst(formatted_raw_ostream &OS);

  /// Print a line to idenfity the start/end of a live element.
  void printBoundaryLine(formatted_raw_ostream &OS,
                         object::SectionedAddress Addr, bool IsEnd);
};

class SourcePrinter {
protected:
  DILineInfo OldLineInfo;
  const object::ObjectFile *Obj = nullptr;
  std::unique_ptr<symbolize::LLVMSymbolizer> Symbolizer;
  // File name to file contents of source.
  StringMap<std::unique_ptr<MemoryBuffer>> SourceCache;
  // Mark the line endings of the cached source.
  StringMap<std::vector<StringRef>> LineCache;
  // Keep track of missing sources.
  StringSet<> MissingSources;
  // Only emit 'invalid debug info' warning once.
  bool WarnedInvalidDebugInfo = false;

private:
  bool cacheSource(const DILineInfo &LineInfoFile);

  void printLines(formatted_raw_ostream &OS, object::SectionedAddress Address,
                  const DILineInfo &LineInfo, StringRef Delimiter,
                  LiveElementPrinter &LEP);

  void printSources(formatted_raw_ostream &OS, const DILineInfo &LineInfo,
                    StringRef ObjectFilename, StringRef Delimiter,
                    LiveElementPrinter &LEP);

  // Returns line source code corresponding to `LineInfo`.
  // Returns empty string if source code cannot be found.
  StringRef getLine(const DILineInfo &LineInfo, StringRef ObjectFilename);

public:
  SourcePrinter() = default;
  SourcePrinter(const object::ObjectFile *Obj, StringRef DefaultArch);
  virtual ~SourcePrinter() = default;
  virtual void printSourceLine(formatted_raw_ostream &OS,
                               object::SectionedAddress Address,
                               StringRef ObjectFilename,
                               LiveElementPrinter &LEP,
                               StringRef Delimiter = "; ");
};

} // namespace objdump
} // namespace llvm

#endif