Dwarfdump base addr entry support

llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h

@@ -36,13 +36,18 @@ class DWARFDataExtractor : public DataExtractor {
   /// Extracts a value and applies a relocation to the result if
   /// one exists for the given offset.
   uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off,
-                             uint64_t *SectionIndex = nullptr) const;
+                             uint64_t *SectionIndex = nullptr,
+                             Error *Err = nullptr) const;
 
   /// Extracts an address-sized value and applies a relocation to the result if
   /// one exists for the given offset.
   uint64_t getRelocatedAddress(uint64_t *Off, uint64_t *SecIx = nullptr) const {
     return getRelocatedValue(getAddressSize(), Off, SecIx);
   }
+  uint64_t getRelocatedAddress(Cursor &C, uint64_t *SecIx = nullptr) const {
+    return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx,
+                             &getError(C));
+  }
 
   /// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding.
   /// There is a DWARF encoding that uses a PC-relative adjustment.

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLoc.h

@@ -29,7 +29,7 @@ class DWARFDebugLoc {
     /// The ending address of the instruction range.
     uint64_t End;
     /// The location of the variable within the specified range.
-    SmallVector<char, 4> Loc;
+    SmallVector<uint8_t, 4> Loc;
   };
 
   /// A list of locations that contain one variable.
@@ -40,8 +40,8 @@ class DWARFDebugLoc {
     /// All the locations in which the variable is stored.
     SmallVector<Entry, 2> Entries;
     /// Dump this list on OS.
-    void dump(raw_ostream &OS, bool IsLittleEndian, unsigned AddressSize,
-              const MCRegisterInfo *MRI, DWARFUnit *U, uint64_t BaseAddress,
+    void dump(raw_ostream &OS, uint64_t BaseAddress, bool IsLittleEndian,
+              unsigned AddressSize, const MCRegisterInfo *MRI, DWARFUnit *U,
               unsigned Indent) const;
   };
 
@@ -68,8 +68,8 @@ class DWARFDebugLoc {
   /// Return the location list at the given offset or nullptr.
   LocationList const *getLocationListAtOffset(uint64_t Offset) const;
 
-  Optional<LocationList> parseOneLocationList(DWARFDataExtractor Data,
-                                              uint64_t *Offset);
+  Expected<LocationList>
+  parseOneLocationList(const DWARFDataExtractor &Data, uint64_t *Offset);
 };
 
 class DWARFDebugLoclists {
@@ -78,7 +78,7 @@ class DWARFDebugLoclists {
     uint8_t Kind;
     uint64_t Value0;
     uint64_t Value1;
-    SmallVector<char, 4> Loc;
+    SmallVector<uint8_t, 4> Loc;
   };
 
   struct LocationList {
@@ -106,8 +106,9 @@ class DWARFDebugLoclists {
   /// Return the location list at the given offset or nullptr.
   LocationList const *getLocationListAtOffset(uint64_t Offset) const;
 
-  static Optional<LocationList>
-  parseOneLocationList(DataExtractor Data, uint64_t *Offset, unsigned Version);
+  static Expected<LocationList> parseOneLocationList(const DataExtractor &Data,
+                                                     uint64_t *Offset,
+                                                     unsigned Version);
 };
 
 } // end namespace llvm

llvm/include/llvm/Support/DataExtractor.h

@@ -11,6 +11,7 @@
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/Error.h"
 
 namespace llvm {
 
@@ -42,6 +43,38 @@ class DataExtractor {
   uint8_t IsLittleEndian;
   uint8_t AddressSize;
 public:
+  /// A class representing a position in a DataExtractor, as well as any error
+  /// encountered during extraction. It enables one to extract a sequence of
+  /// values without error-checking and then checking for errors in bulk at the
+  /// end. The class holds an Error object, so failing to check the result of
+  /// the parse will result in a runtime error. The error flag is sticky and
+  /// will cause all subsequent extraction functions to fail without even
+  /// attempting to parse and without updating the Cursor offset. After clearing
+  /// the error flag, one can again use the Cursor object for parsing.
+  class Cursor {
+    uint64_t Offset;
+    Error Err;
+
+    friend class DataExtractor;
+
+  public:
+    /// Construct a cursor for extraction from the given offset.
+    explicit Cursor(uint64_t Offset) : Offset(Offset), Err(Error::success()) {}
+
+    /// Checks whether the cursor is valid (i.e. no errors were encountered). In
+    /// case of errors, this does not clear the error flag -- one must call
+    /// takeError() instead.
+    explicit operator bool() { return !Err; }
+
+    /// Return the current position of this Cursor. In the error state this is
+    /// the position of the Cursor before the first error was encountered.
+    uint64_t tell() const { return Offset; }
+
+    /// Return error contained inside this Cursor, if any. Clears the internal
+    /// Cursor state.
+    Error takeError() { return std::move(Err); }
+  };
+
   /// Construct with a buffer that is owned by the caller.
   ///
   /// This constructor allows us to use data that is owned by the
@@ -124,10 +157,24 @@ class DataExtractor {
   /// @param[in] byte_size
   ///     The size in byte of the integer to extract.
   ///
+  /// @param[in,out] Err
+  ///     A pointer to an Error object. Upon return the Error object is set to
+  ///     indicate the result (success/failure) of the function. If the Error
+  ///     object is already set when calling this function, no extraction is
+  ///     performed.
+  ///
   /// @return
   ///     The unsigned integer value that was extracted, or zero on
   ///     failure.
-  uint64_t getUnsigned(uint64_t *offset_ptr, uint32_t byte_size) const;
+  uint64_t getUnsigned(uint64_t *offset_ptr, uint32_t byte_size,
+                       Error *Err = nullptr) const;
+
+  /// Extract an unsigned integer of the given size from the location given by
+  /// the cursor. In case of an extraction error, or if the cursor is already in
+  /// an error state, zero is returned.
+  uint64_t getUnsigned(Cursor &C, uint32_t Size) const {
+    return getUnsigned(&C.Offset, Size, &C.Err);
+  }
 
   /// Extract an signed integer of size \a byte_size from \a *offset_ptr.
   ///
@@ -175,6 +222,11 @@ class DataExtractor {
     return getUnsigned(offset_ptr, AddressSize);
   }
 
+  /// Extract a pointer-sized unsigned integer from the location given by the
+  /// cursor. In case of an extraction error, or if the cursor is already in
+  /// an error state, zero is returned.
+  uint64_t getAddress(Cursor &C) const { return getUnsigned(C, AddressSize); }
+
   /// Extract a uint8_t value from \a *offset_ptr.
   ///
   /// Extract a single uint8_t from the binary data at the offset
@@ -187,9 +239,20 @@ class DataExtractor {
   ///     enough bytes to extract this value, the offset will be left
   ///     unmodified.
   ///
+  /// @param[in,out] Err
+  ///     A pointer to an Error object. Upon return the Error object is set to
+  ///     indicate the result (success/failure) of the function. If the Error
+  ///     object is already set when calling this function, no extraction is
+  ///     performed.
+  ///
   /// @return
   ///     The extracted uint8_t value.
-  uint8_t getU8(uint64_t *offset_ptr) const;
+  uint8_t getU8(uint64_t *offset_ptr, Error *Err = nullptr) const;
+
+  /// Extract a single uint8_t value from the location given by the cursor. In
+  /// case of an extraction error, or if the cursor is already in an error
+  /// state, zero is returned.
+  uint8_t getU8(Cursor &C) const { return getU8(&C.Offset, &C.Err); }
 
   /// Extract \a count uint8_t values from \a *offset_ptr.
   ///
@@ -216,6 +279,26 @@ class DataExtractor {
   ///     NULL otherise.
   uint8_t *getU8(uint64_t *offset_ptr, uint8_t *dst, uint32_t count) const;
 
+  /// Extract \a Count uint8_t values from the location given by the cursor and
+  /// store them into the destination buffer. In case of an extraction error, or
+  /// if the cursor is already in an error state, a nullptr is returned and the
+  /// destination buffer is left unchanged.
+  uint8_t *getU8(Cursor &C, uint8_t *Dst, uint32_t Count) const;
+
+  /// Extract \a Count uint8_t values from the location given by the cursor and
+  /// store them into the destination vector. The vector is resized to fit the
+  /// extracted data. In case of an extraction error, or if the cursor is
+  /// already in an error state, the destination vector is left unchanged and
+  /// cursor is placed into an error state.
+  void getU8(Cursor &C, SmallVectorImpl<uint8_t> &Dst, uint32_t Count) const {
+    if (isValidOffsetForDataOfSize(C.Offset, Count))
+      Dst.resize(Count);
+
+    // This relies on the fact that getU8 will not attempt to write to the
+    // buffer if isValidOffsetForDataOfSize(C.Offset, Count) is false.
+    getU8(C, Dst.data(), Count);
+  }
+
   //------------------------------------------------------------------
   /// Extract a uint16_t value from \a *offset_ptr.
   ///
@@ -229,10 +312,21 @@ class DataExtractor {
   ///     enough bytes to extract this value, the offset will be left
   ///     unmodified.
   ///
+  /// @param[in,out] Err
+  ///     A pointer to an Error object. Upon return the Error object is set to
+  ///     indicate the result (success/failure) of the function. If the Error
+  ///     object is already set when calling this function, no extraction is
+  ///     performed.
+  ///
   /// @return
   ///     The extracted uint16_t value.
   //------------------------------------------------------------------
-  uint16_t getU16(uint64_t *offset_ptr) const;
+  uint16_t getU16(uint64_t *offset_ptr, Error *Err = nullptr) const;
+
+  /// Extract a single uint16_t value from the location given by the cursor. In
+  /// case of an extraction error, or if the cursor is already in an error
+  /// state, zero is returned.
+  uint16_t getU16(Cursor &C) const { return getU16(&C.Offset, &C.Err); }
 
   /// Extract \a count uint16_t values from \a *offset_ptr.
   ///
@@ -288,9 +382,20 @@ class DataExtractor {
   ///     enough bytes to extract this value, the offset will be left
   ///     unmodified.
   ///
+  /// @param[in,out] Err
+  ///     A pointer to an Error object. Upon return the Error object is set to
+  ///     indicate the result (success/failure) of the function. If the Error
+  ///     object is already set when calling this function, no extraction is
+  ///     performed.
+  ///
   /// @return
   ///     The extracted uint32_t value.
-  uint32_t getU32(uint64_t *offset_ptr) const;
+  uint32_t getU32(uint64_t *offset_ptr, Error *Err = nullptr) const;
+
+  /// Extract a single uint32_t value from the location given by the cursor. In
+  /// case of an extraction error, or if the cursor is already in an error
+  /// state, zero is returned.
+  uint32_t getU32(Cursor &C) const { return getU32(&C.Offset, &C.Err); }
 
   /// Extract \a count uint32_t values from \a *offset_ptr.
   ///
@@ -329,9 +434,20 @@ class DataExtractor {
   ///     enough bytes to extract this value, the offset will be left
   ///     unmodified.
   ///
+  /// @param[in,out] Err
+  ///     A pointer to an Error object. Upon return the Error object is set to
+  ///     indicate the result (success/failure) of the function. If the Error
+  ///     object is already set when calling this function, no extraction is
+  ///     performed.
+  ///
   /// @return
   ///     The extracted uint64_t value.
-  uint64_t getU64(uint64_t *offset_ptr) const;
+  uint64_t getU64(uint64_t *offset_ptr, Error *Err = nullptr) const;
+
+  /// Extract a single uint64_t value from the location given by the cursor. In
+  /// case of an extraction error, or if the cursor is already in an error
+  /// state, zero is returned.
+  uint64_t getU64(Cursor &C) const { return getU64(&C.Offset, &C.Err); }
 
   /// Extract \a count uint64_t values from \a *offset_ptr.
   ///
@@ -390,9 +506,30 @@ class DataExtractor {
   ///     enough bytes to extract this value, the offset will be left
   ///     unmodified.
   ///
+  /// @param[in,out] Err
+  ///     A pointer to an Error object. Upon return the Error object is set to
+  ///     indicate the result (success/failure) of the function. If the Error
+  ///     object is already set when calling this function, no extraction is
+  ///     performed.
+  ///
   /// @return
   ///     The extracted unsigned integer value.
-  uint64_t getULEB128(uint64_t *offset_ptr) const;
+  uint64_t getULEB128(uint64_t *offset_ptr, llvm::Error *Err = nullptr) const;
+
+  /// Extract an unsigned ULEB128 value from the location given by the cursor.
+  /// In case of an extraction error, or if the cursor is already in an error
+  /// state, zero is returned.
+  uint64_t getULEB128(Cursor &C) const { return getULEB128(&C.Offset, &C.Err); }
+
+  /// Advance the Cursor position by the given number of bytes. No-op if the
+  /// cursor is in an error state.
+  void skip(Cursor &C, uint64_t Length) const;
+
+  /// Return true iff the cursor is at the end of the buffer, regardless of the
+  /// error state of the cursor. The only way both eof and error states can be
+  /// true is if one attempts a read while the cursor is at the very end of the
+  /// data buffer.
+  bool eof(const Cursor &C) const { return Data.size() == C.Offset; }
 
   /// Test the validity of \a offset.
   ///
@@ -420,6 +557,12 @@ class DataExtractor {
   bool isValidOffsetForAddress(uint64_t offset) const {
     return isValidOffsetForDataOfSize(offset, AddressSize);
   }
+
+protected:
+  // Make it possible for subclasses to access these fields without making them
+  // public.
+  static uint64_t &getOffset(Cursor &C) { return C.Offset; }
+  static Error &getError(Cursor &C) { return C.Err; }
 };
 
 } // namespace llvm

llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp

@@ -13,13 +13,14 @@
 using namespace llvm;
 
 uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint64_t *Off,
-                                               uint64_t *SecNdx) const {
+                                               uint64_t *SecNdx,
+                                               Error *Err) const {
   if (SecNdx)
     *SecNdx = object::SectionedAddress::UndefSection;
   if (!Section)
-    return getUnsigned(Off, Size);
+    return getUnsigned(Off, Size, Err);
   Optional<RelocAddrEntry> E = Obj->find(*Section, *Off);
-  uint64_t A = getUnsigned(Off, Size);
+  uint64_t A = getUnsigned(Off, Size, Err);
   if (!E)
     return A;
   if (SecNdx)