Separate UnwindTable from DWARF Debug Frame

Author: Amirhossein Pashaeehir

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h

@@ -9,14 +9,13 @@
 #ifndef LLVM_DEBUGINFO_DWARF_DWARFDEBUGFRAME_H
 #define LLVM_DEBUGINFO_DWARF_DWARFDEBUGFRAME_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/DebugInfo/DWARF/DWARFCFIProgram.h"
 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
+#include "llvm/DebugInfo/DWARF/DWARFUnwindTable.h"
 #include "llvm/Support/Error.h"
 #include "llvm/TargetParser/Triple.h"
-#include <map>
 #include <memory>
 #include <vector>
 
@@ -29,358 +28,6 @@ struct DIDumpOptions;
 
 namespace dwarf {
 
-constexpr uint32_t InvalidRegisterNumber = UINT32_MAX;
-
-/// A class that represents a location for the Call Frame Address (CFA) or a
-/// register. This is decoded from the DWARF Call Frame Information
-/// instructions and put into an UnwindRow.
-class UnwindLocation {
-public:
-  enum Location {
-    /// Not specified.
-    Unspecified,
-    /// Register is not available and can't be recovered.
-    Undefined,
-    /// Register value is in the register, nothing needs to be done to unwind
-    /// it:
-    ///   reg = reg
-    Same,
-    /// Register is in or at the CFA plus an offset:
-    ///   reg = CFA + offset
-    ///   reg = defef(CFA + offset)
-    CFAPlusOffset,
-    /// Register or CFA is in or at a register plus offset, optionally in
-    /// an address space:
-    ///   reg = reg + offset [in addrspace]
-    ///   reg = deref(reg + offset [in addrspace])
-    RegPlusOffset,
-    /// Register or CFA value is in or at a value found by evaluating a DWARF
-    /// expression:
-    ///   reg = eval(dwarf_expr)
-    ///   reg = deref(eval(dwarf_expr))
-    DWARFExpr,
-    /// Value is a constant value contained in "Offset":
-    ///   reg = Offset
-    Constant,
-  };
-
-private:
-  Location Kind;   /// The type of the location that describes how to unwind it.
-  uint32_t RegNum; /// The register number for Kind == RegPlusOffset.
-  int32_t Offset;  /// The offset for Kind == CFAPlusOffset or RegPlusOffset.
-  std::optional<uint32_t> AddrSpace;   /// The address space for Kind ==
-                                       /// RegPlusOffset for CFA.
-  std::optional<DWARFExpression> Expr; /// The DWARF expression for Kind ==
-                                       /// DWARFExpression.
-  bool Dereference; /// If true, the resulting location must be dereferenced
-                    /// after the location value is computed.
-
-  // Constructors are private to force people to use the create static
-  // functions.
-  UnwindLocation(Location K)
-      : Kind(K), RegNum(InvalidRegisterNumber), Offset(0),
-        AddrSpace(std::nullopt), Dereference(false) {}
-
-  UnwindLocation(Location K, uint32_t Reg, int32_t Off,
-                 std::optional<uint32_t> AS, bool Deref)
-      : Kind(K), RegNum(Reg), Offset(Off), AddrSpace(AS), Dereference(Deref) {}
-
-  UnwindLocation(DWARFExpression E, bool Deref)
-      : Kind(DWARFExpr), RegNum(InvalidRegisterNumber), Offset(0), Expr(E),
-        Dereference(Deref) {}
-
-public:
-  /// Create a location whose rule is set to Unspecified. This means the
-  /// register value might be in the same register but it wasn't specified in
-  /// the unwind opcodes.
-  static UnwindLocation createUnspecified();
-  /// Create a location where the value is undefined and not available. This can
-  /// happen when a register is volatile and can't be recovered.
-  static UnwindLocation createUndefined();
-  /// Create a location where the value is known to be in the register itself.
-  static UnwindLocation createSame();
-  /// Create a location that is in (Deref == false) or at (Deref == true) the
-  /// CFA plus an offset. Most registers that are spilled onto the stack use
-  /// this rule. The rule for the register will use this rule and specify a
-  /// unique offset from the CFA with \a Deref set to true. This value will be
-  /// relative to a CFA value which is typically defined using the register
-  /// plus offset location. \see createRegisterPlusOffset(...) for more
-  /// information.
-  static UnwindLocation createIsCFAPlusOffset(int32_t Off);
-  static UnwindLocation createAtCFAPlusOffset(int32_t Off);
-  /// Create a location where the saved value is in (Deref == false) or at
-  /// (Deref == true) a regiser plus an offset and, optionally, in the specified
-  /// address space (used mostly for the CFA).
-  ///
-  /// The CFA is usually defined using this rule by using the stack pointer or
-  /// frame pointer as the register, with an offset that accounts for all
-  /// spilled registers and all local variables in a function, and Deref ==
-  /// false.
-  static UnwindLocation
-  createIsRegisterPlusOffset(uint32_t Reg, int32_t Off,
-                             std::optional<uint32_t> AddrSpace = std::nullopt);
-  static UnwindLocation
-  createAtRegisterPlusOffset(uint32_t Reg, int32_t Off,
-                             std::optional<uint32_t> AddrSpace = std::nullopt);
-  /// Create a location whose value is the result of evaluating a DWARF
-  /// expression. This allows complex expressions to be evaluated in order to
-  /// unwind a register or CFA value.
-  static UnwindLocation createIsDWARFExpression(DWARFExpression Expr);
-  static UnwindLocation createAtDWARFExpression(DWARFExpression Expr);
-  static UnwindLocation createIsConstant(int32_t Value);
-
-  Location getLocation() const { return Kind; }
-  uint32_t getRegister() const { return RegNum; }
-  int32_t getOffset() const { return Offset; }
-  uint32_t getAddressSpace() const {
-    assert(Kind == RegPlusOffset && AddrSpace);
-    return *AddrSpace;
-  }
-  int32_t getConstant() const { return Offset; }
-  /// Some opcodes will modify the CFA location's register only, so we need
-  /// to be able to modify the CFA register when evaluating DWARF Call Frame
-  /// Information opcodes.
-  void setRegister(uint32_t NewRegNum) { RegNum = NewRegNum; }
-  /// Some opcodes will modify the CFA location's offset only, so we need
-  /// to be able to modify the CFA offset when evaluating DWARF Call Frame
-  /// Information opcodes.
-  void setOffset(int32_t NewOffset) { Offset = NewOffset; }
-  /// Some opcodes modify a constant value and we need to be able to update
-  /// the constant value (DW_CFA_GNU_window_save which is also known as
-  // DW_CFA_AARCH64_negate_ra_state).
-  void setConstant(int32_t Value) { Offset = Value; }
-
-  std::optional<DWARFExpression> getDWARFExpressionBytes() const {
-    return Expr;
-  }
-  /// Dump a location expression as text and use the register information if
-  /// some is provided.
-  ///
-  /// \param OS the stream to use for output.
-  ///
-  /// \param MRI register information that helps emit register names insteead
-  /// of raw register numbers.
-  ///
-  /// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
-  /// instead of from .debug_frame. This is needed for register number
-  /// conversion because some register numbers differ between the two sections
-  /// for certain architectures like x86.
-  void dump(raw_ostream &OS, DIDumpOptions DumpOpts) const;
-
-  bool operator==(const UnwindLocation &RHS) const;
-};
-
-raw_ostream &operator<<(raw_ostream &OS, const UnwindLocation &R);
-
-/// A class that can track all registers with locations in a UnwindRow object.
-///
-/// Register locations use a map where the key is the register number and the
-/// the value is a UnwindLocation.
-///
-/// The register maps are put into a class so that all register locations can
-/// be copied when parsing the unwind opcodes DW_CFA_remember_state and
-/// DW_CFA_restore_state.
-class RegisterLocations {
-  std::map<uint32_t, UnwindLocation> Locations;
-
-public:
-  /// Return the location for the register in \a RegNum if there is a location.
-  ///
-  /// \param RegNum the register number to find a location for.
-  ///
-  /// \returns A location if one is available for \a RegNum, or std::nullopt
-  /// otherwise.
-  std::optional<UnwindLocation> getRegisterLocation(uint32_t RegNum) const {
-    auto Pos = Locations.find(RegNum);
-    if (Pos == Locations.end())
-      return std::nullopt;
-    return Pos->second;
-  }
-
-  /// Set the location for the register in \a RegNum to \a Location.
-  ///
-  /// \param RegNum the register number to set the location for.
-  ///
-  /// \param Location the UnwindLocation that describes how to unwind the value.
-  void setRegisterLocation(uint32_t RegNum, const UnwindLocation &Location) {
-    Locations.erase(RegNum);
-    Locations.insert(std::make_pair(RegNum, Location));
-  }
-
-  /// Removes any rule for the register in \a RegNum.
-  ///
-  /// \param RegNum the register number to remove the location for.
-  void removeRegisterLocation(uint32_t RegNum) { Locations.erase(RegNum); }
-
-  /// Dump all registers + locations that are currently defined in this object.
-  ///
-  /// \param OS the stream to use for output.
-  ///
-  /// \param MRI register information that helps emit register names insteead
-  /// of raw register numbers.
-  ///
-  /// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
-  /// instead of from .debug_frame. This is needed for register number
-  /// conversion because some register numbers differ between the two sections
-  /// for certain architectures like x86.
-  void dump(raw_ostream &OS, DIDumpOptions DumpOpts) const;
-
-  /// Returns true if we have any register locations in this object.
-  bool hasLocations() const { return !Locations.empty(); }
-
-  size_t size() const { return Locations.size(); }
-
-  bool operator==(const RegisterLocations &RHS) const {
-    return Locations == RHS.Locations;
-  }
-};
-
-raw_ostream &operator<<(raw_ostream &OS, const RegisterLocations &RL);
-
-/// A class that represents a single row in the unwind table that is decoded by
-/// parsing the DWARF Call Frame Information opcodes.
-///
-/// The row consists of an optional address, the rule to unwind the CFA and all
-/// rules to unwind any registers. If the address doesn't have a value, this
-/// row represents the initial instructions for a CIE. If the address has a
-/// value the UnwindRow represents a row in the UnwindTable for a FDE. The
-/// address is the first address for which the CFA location and register rules
-/// are valid within a function.
-///
-/// UnwindRow objects are created by parsing opcodes in the DWARF Call Frame
-/// Information and UnwindRow objects are lazily populated and pushed onto a
-/// stack in the UnwindTable when evaluating this state machine. Accessors are
-/// needed for the address, CFA value, and register locations as the opcodes
-/// encode a state machine that produces a sorted array of UnwindRow objects
-/// \see UnwindTable.
-class UnwindRow {
-  /// The address will be valid when parsing the instructions in a FDE. If
-  /// invalid, this object represents the initial instructions of a CIE.
-  std::optional<uint64_t> Address; ///< Address for row in FDE, invalid for CIE.
-  UnwindLocation CFAValue;    ///< How to unwind the Call Frame Address (CFA).
-  RegisterLocations RegLocs;  ///< How to unwind all registers in this list.
-
-public:
-  UnwindRow() : CFAValue(UnwindLocation::createUnspecified()) {}
-
-  /// Returns true if the address is valid in this object.
-  bool hasAddress() const { return Address.has_value(); }
-
-  /// Get the address for this row.
-  ///
-  /// Clients should only call this function after verifying it has a valid
-  /// address with a call to \see hasAddress().
-  uint64_t getAddress() const { return *Address; }
-
-  /// Set the address for this UnwindRow.
-  ///
-  /// The address represents the first address for which the CFAValue and
-  /// RegLocs are valid within a function.
-  void setAddress(uint64_t Addr) { Address = Addr; }
-
-  /// Offset the address for this UnwindRow.
-  ///
-  /// The address represents the first address for which the CFAValue and
-  /// RegLocs are valid within a function. Clients must ensure that this object
-  /// already has an address (\see hasAddress()) prior to calling this
-  /// function.
-  void slideAddress(uint64_t Offset) { *Address += Offset; }
-  UnwindLocation &getCFAValue() { return CFAValue; }
-  const UnwindLocation &getCFAValue() const { return CFAValue; }
-  RegisterLocations &getRegisterLocations() { return RegLocs; }
-  const RegisterLocations &getRegisterLocations() const { return RegLocs; }
-
-  /// Dump the UnwindRow to the stream.
-  ///
-  /// \param OS the stream to use for output.
-  ///
-  /// \param MRI register information that helps emit register names insteead
-  /// of raw register numbers.
-  ///
-  /// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
-  /// instead of from .debug_frame. This is needed for register number
-  /// conversion because some register numbers differ between the two sections
-  /// for certain architectures like x86.
-  ///
-  /// \param IndentLevel specify the indent level as an integer. The UnwindRow
-  /// will be output to the stream preceded by 2 * IndentLevel number of spaces.
-  void dump(raw_ostream &OS, DIDumpOptions DumpOpts,
-            unsigned IndentLevel = 0) const;
-};
-
-raw_ostream &operator<<(raw_ostream &OS, const UnwindRow &Row);
-
-/// A class that contains all UnwindRow objects for an FDE or a single unwind
-/// row for a CIE. To unwind an address the rows, which are sorted by start
-/// address, can be searched to find the UnwindRow with the lowest starting
-/// address that is greater than or equal to the address that is being looked
-/// up.
-class UnwindTable {
-public:
-  using RowContainer = std::vector<UnwindRow>;
-  using iterator = RowContainer::iterator;
-  using const_iterator = RowContainer::const_iterator;
-
-  size_t size() const { return Rows.size(); }
-  iterator begin() { return Rows.begin(); }
-  const_iterator begin() const { return Rows.begin(); }
-  iterator end() { return Rows.end(); }
-  const_iterator end() const { return Rows.end(); }
-  const UnwindRow &operator[](size_t Index) const {
-    assert(Index < size());
-    return Rows[Index];
-  }
-  void insertRow(const UnwindRow &Row) { Rows.push_back(Row); }
-
-  /// Set the last address that this unwinding table refers to.
-  ///
-  /// This is used when this table is created based on a FDE.
-  void setEndAddress(uint64_t Addr) { EndAddress = Addr; }
-
-  /// Dump the UnwindTable to the stream.
-  ///
-  /// \param OS the stream to use for output.
-  ///
-  /// \param MRI register information that helps emit register names insteead
-  /// of raw register numbers.
-  ///
-  /// \param IsEH true if the DWARF Call Frame Information is from .eh_frame
-  /// instead of from .debug_frame. This is needed for register number
-  /// conversion because some register numbers differ between the two sections
-  /// for certain architectures like x86.
-  ///
-  /// \param IndentLevel specify the indent level as an integer. The UnwindRow
-  /// will be output to the stream preceded by 2 * IndentLevel number of spaces.
-  void dump(raw_ostream &OS, DIDumpOptions DumpOpts,
-            unsigned IndentLevel = 0) const;
-
-  /// Parse the information in the CFIProgram and update the CurrRow object
-  /// that the state machine describes.
-  ///
-  /// This is an internal implementation that emulates the state machine
-  /// described in the DWARF Call Frame Information opcodes and will push
-  /// CurrRow onto the Rows container when needed.
-  ///
-  /// \param CFIP the CFI program that contains the opcodes from a CIE or FDE.
-  ///
-  /// \param CurrRow the current row to modify while parsing the state machine.
-  ///
-  /// \param InitialLocs If non-NULL, we are parsing a FDE and this contains
-  /// the initial register locations from the CIE. If NULL, then a CIE's
-  /// opcodes are being parsed and this is not needed. This is used for the
-  /// DW_CFA_restore and DW_CFA_restore_extended opcodes.
-  Error parseRows(const CFIProgram &CFIP, UnwindRow &CurrRow,
-                  const RegisterLocations *InitialLocs);
-
-private:
-  RowContainer Rows;
-  /// The end address when data is extracted from a FDE. This value will be
-  /// invalid when a UnwindTable is extracted from a CIE.
-  std::optional<uint64_t> EndAddress;
-};
-
-raw_ostream &operator<<(raw_ostream &OS, const UnwindTable &Rows);
-
 class CIE;
 
 /// Create an UnwindTable from a Common Information Entry (CIE).