[DWARF] NFC: Collect info used by DWARFFormValue into a helper.

Some forms have sizes that depend on the DWARF version, DWARF format
(32/64-bit), or the size of an address.  Collect these into a struct
to simplify passing them around.  Require callers to provide one when
they query a form's size.

Differential Revision: http://reviews.llvm.org/D34570


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306315 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/DebugInfo/DWARF/DWARFDebugLine.h

@@ -12,6 +12,7 @@
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/DIContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
 #include "llvm/Support/DataExtractor.h"
 #include <cstdint>
@@ -43,10 +44,10 @@ public:
     /// The size in bytes of the statement information for this compilation unit
     /// (not including the total_length field itself).
     uint64_t TotalLength;
-    /// Version identifier for the statement information format.
-    uint16_t Version;
-    /// In v5, size in bytes of an address (or segment offset).
-    uint8_t AddressSize;
+    /// Version, address size (starting in v5), and DWARF32/64 format; these
+    /// parameters affect interpretation of forms (used in the directory and
+    /// file tables starting with v5).
+    DWARFFormParams FormParams;
     /// In v5, size in bytes of a segment selector.
     uint8_t SegSelectorSize;
     /// The number of bytes following the prologue_length field to the beginning
@@ -71,15 +72,18 @@ public:
     std::vector<StringRef> IncludeDirectories;
     std::vector<FileNameEntry> FileNames;
 
-    bool IsDWARF64;
+    const DWARFFormParams getFormParams() const { return FormParams; }
+    uint16_t getVersion() const { return FormParams.Version; }
+    uint8_t getAddressSize() const { return FormParams.AddrSize; }
+    bool isDWARF64() const { return FormParams.Format == dwarf::DWARF64; }
 
-    uint32_t sizeofTotalLength() const { return IsDWARF64 ? 12 : 4; }
+    uint32_t sizeofTotalLength() const { return isDWARF64() ? 12 : 4; }
 
-    uint32_t sizeofPrologueLength() const { return IsDWARF64 ? 8 : 4; }
+    uint32_t sizeofPrologueLength() const { return isDWARF64() ? 8 : 4; }
 
     /// Length of the prologue in bytes.
     uint32_t getLength() const {
-      return PrologueLength + sizeofTotalLength() + sizeof(Version) +
+      return PrologueLength + sizeofTotalLength() + sizeof(getVersion()) +
              sizeofPrologueLength();
     }
 

include/llvm/DebugInfo/DWARF/DWARFFormValue.h

@@ -22,6 +22,35 @@ namespace llvm {
 class DWARFUnit;
 class raw_ostream;
 
+/// A helper struct for DWARFFormValue methods, providing information that
+/// allows it to know the byte size of DW_FORM values that vary in size
+/// depending on the DWARF version, address byte size, or DWARF32/DWARF64.
+struct DWARFFormParams {
+  uint16_t Version;
+  uint8_t AddrSize;
+  dwarf::DwarfFormat Format;
+
+  /// The definition of the size of form DW_FORM_ref_addr depends on the
+  /// version. In DWARF v2 it's the size of an address; after that, it's the
+  /// size of a reference.
+  uint8_t getRefAddrByteSize() const {
+    if (Version == 2)
+      return AddrSize;
+    return getDwarfOffsetByteSize();
+  }
+
+  /// The size of a reference is determined by the DWARF 32/64-bit format.
+  uint8_t getDwarfOffsetByteSize() const {
+    switch (Format) {
+    case dwarf::DwarfFormat::DWARF32:
+      return 4;
+    case dwarf::DwarfFormat::DWARF64:
+      return 8;
+    }
+    llvm_unreachable("Invalid Format value");
+  }
+};
+
 class DWARFFormValue {
 public:
   enum FormClass {
@@ -104,79 +133,43 @@ public:
 
   /// Get the fixed byte size for a given form.
   ///
-  /// If the form always has a fixed valid byte size that doesn't depend on a
-  /// DWARFUnit, then an Optional with a value will be returned. If the form
-  /// can vary in size depending on the DWARFUnit (DWARF version, address byte
-  /// size, or DWARF 32/64) and the DWARFUnit is valid, then an Optional with a
-  /// valid value is returned. If the form is always encoded using a variable
-  /// length storage format (ULEB or SLEB numbers or blocks) or the size
-  /// depends on a DWARFUnit and the DWARFUnit is NULL, then None will be
-  /// returned.
-  /// \param Form The DWARF form to get the fixed byte size for
-  /// \param U The DWARFUnit that can be used to help determine the byte size.
-  ///
-  /// \returns Optional<uint8_t> value with the fixed byte size or None if
-  /// \p Form doesn't have a fixed byte size or a DWARFUnit wasn't supplied
-  /// and was needed to calculate the byte size.
-  static Optional<uint8_t> getFixedByteSize(dwarf::Form Form,
-                                            const DWARFUnit *U = nullptr);
-
-  /// Get the fixed byte size for a given form.
-  ///
-  /// If the form has a fixed byte size given a valid DWARF version and address
-  /// byte size, then an Optional with a valid value is returned. If the form
-  /// is always encoded using a variable length storage format (ULEB or SLEB
-  /// numbers or blocks) then None will be returned.
+  /// If the form has a fixed byte size, then an Optional with a value will be
+  /// returned. If the form is always encoded using a variable length storage
+  /// format (ULEB or SLEB numbers or blocks) then None will be returned.
   ///
-  /// \param Form DWARF form to get the fixed byte size for
-  /// \param Version DWARF version number.
-  /// \param AddrSize size of an address in bytes.
-  /// \param Format enum value from llvm::dwarf::DwarfFormat.
+  /// \param Form DWARF form to get the fixed byte size for.
+  /// \param FormParams DWARF parameters to help interpret forms.
   /// \returns Optional<uint8_t> value with the fixed byte size or None if
   /// \p Form doesn't have a fixed byte size.
-  static Optional<uint8_t> getFixedByteSize(dwarf::Form Form, uint16_t Version,
-                                            uint8_t AddrSize,
-                                            llvm::dwarf::DwarfFormat Format);
+  static Optional<uint8_t> getFixedByteSize(dwarf::Form Form,
+                                            const DWARFFormParams &FormParams);
 
-  /// Skip a form in \p DebugInfoData at offset specified by \p OffsetPtr.
+  /// Skip a form's value in \p DebugInfoData at the offset specified by
+  /// \p OffsetPtr.
   ///
-  /// Skips the bytes for this form in the debug info and updates the offset.
+  /// Skips the bytes for the current form and updates the offset.
   ///
-  /// \param DebugInfoData the .debug_info data to use to skip the value.
-  /// \param OffsetPtr a reference to the offset that will be updated.
-  /// \param U the DWARFUnit to use when skipping the form in case the form
-  /// size differs according to data in the DWARFUnit.
+  /// \param DebugInfoData The data where we want to skip the value.
+  /// \param OffsetPtr A reference to the offset that will be updated.
+  /// \param Params DWARF parameters to help interpret forms.
   /// \returns true on success, false if the form was not skipped.
   bool skipValue(DataExtractor DebugInfoData, uint32_t *OffsetPtr,
-                 const DWARFUnit *U) const;
-
-  /// Skip a form in \p DebugInfoData at offset specified by \p OffsetPtr.
-  ///
-  /// Skips the bytes for this form in the debug info and updates the offset.
-  ///
-  /// \param Form the DW_FORM enumeration that indicates the form to skip.
-  /// \param DebugInfoData the .debug_info data to use to skip the value.
-  /// \param OffsetPtr a reference to the offset that will be updated.
-  /// \param U the DWARFUnit to use when skipping the form in case the form
-  /// size differs according to data in the DWARFUnit.
-  /// \returns true on success, false if the form was not skipped.
-  static bool skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
-                        uint32_t *OffsetPtr, const DWARFUnit *U);
+                 const DWARFFormParams &Params) const {
+    return DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, Params);
+  }
 
-  /// Skip a form in \p DebugInfoData at offset specified by \p OffsetPtr.
+  /// Skip a form's value in \p DebugInfoData at the offset specified by
+  /// \p OffsetPtr.
   ///
-  /// Skips the bytes for this form in the debug info and updates the offset.
+  /// Skips the bytes for the specified form and updates the offset.
   ///
-  /// \param Form the DW_FORM enumeration that indicates the form to skip.
-  /// \param DebugInfoData the .debug_info data to use to skip the value.
-  /// \param OffsetPtr a reference to the offset that will be updated.
-  /// \param Version DWARF version number.
-  /// \param AddrSize size of an address in bytes.
-  /// \param Format enum value from llvm::dwarf::DwarfFormat.
+  /// \param Form The DW_FORM enumeration that indicates the form to skip.
+  /// \param DebugInfoData The data where we want to skip the value.
+  /// \param OffsetPtr A reference to the offset that will be updated.
+  /// \param FormParams DWARF parameters to help interpret forms.
   /// \returns true on success, false if the form was not skipped.
   static bool skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
-                        uint32_t *OffsetPtr, uint16_t Version, uint8_t AddrSize,
-                        llvm::dwarf::DwarfFormat Format);
+                        uint32_t *OffsetPtr, const DWARFFormParams &FormParams);
 
 private:
   void dumpString(raw_ostream &OS) const;

include/llvm/DebugInfo/DWARF/DWARFUnit.h

@@ -19,6 +19,7 @@
 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
@@ -127,12 +128,13 @@ class DWARFUnit {
   bool isDWO;
   const DWARFUnitSectionBase &UnitSection;
 
+  // Version, address size, and DWARF format.
+  DWARFFormParams FormParams;
+
   uint32_t Offset;
   uint32_t Length;
   const DWARFAbbreviationDeclarationSet *Abbrevs;
-  uint16_t Version;
   uint8_t UnitType;
-  uint8_t AddrSize;
   uint64_t BaseAddr;
   /// The compile unit debug information entry items.
   std::vector<DWARFDebugInfoEntry> DieArray;
@@ -159,7 +161,7 @@ protected:
   virtual bool extractImpl(DataExtractor debug_info, uint32_t *offset_ptr);
 
   /// Size in bytes of the unit header.
-  virtual uint32_t getHeaderSize() const { return Version <= 4 ? 11 : 12; }
+  virtual uint32_t getHeaderSize() const { return getVersion() <= 4 ? 11 : 12; }
 
 public:
   DWARFUnit(DWARFContext &Context, const DWARFSection &Section,
@@ -197,7 +199,8 @@ public:
   uint64_t getStringOffsetSectionRelocation(uint32_t Index) const;
 
   DataExtractor getDebugInfoExtractor() const {
-    return DataExtractor(InfoSection.Data, isLittleEndian, AddrSize);
+    return DataExtractor(InfoSection.Data, isLittleEndian,
+                         getAddressByteSize());
   }
 
   DataExtractor getStringExtractor() const {
@@ -220,10 +223,14 @@ public:
   uint32_t getOffset() const { return Offset; }
   uint32_t getNextUnitOffset() const { return Offset + Length + 4; }
   uint32_t getLength() const { return Length; }
-  uint16_t getVersion() const { return Version; }
 
-  dwarf::DwarfFormat getFormat() const {
-    return dwarf::DwarfFormat::DWARF32; // FIXME: Support DWARF64.
+  const DWARFFormParams &getFormParams() const { return FormParams; }
+  uint16_t getVersion() const { return FormParams.Version; }
+  dwarf::DwarfFormat getFormat() const { return FormParams.Format; }
+  uint8_t getAddressByteSize() const { return FormParams.AddrSize; }
+  uint8_t getRefAddrByteSize() const { return FormParams.getRefAddrByteSize(); }
+  uint8_t getDwarfOffsetByteSize() const {
+    return FormParams.getDwarfOffsetByteSize();
   }
 
   const DWARFAbbreviationDeclarationSet *getAbbreviations() const {
@@ -231,19 +238,6 @@ public:
   }
 
   uint8_t getUnitType() const { return UnitType; }
-  uint8_t getAddressByteSize() const { return AddrSize; }
-
-  uint8_t getRefAddrByteSize() const {
-    if (Version == 2)
-      return AddrSize;
-    return getDwarfOffsetByteSize();
-  }
-
-  uint8_t getDwarfOffsetByteSize() const {
-    if (getFormat() == dwarf::DwarfFormat::DWARF64)
-      return 8;
-    return 4;
-  }
 
   uint64_t getBaseAddress() const { return BaseAddr; }
 

lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp

@@ -65,46 +65,52 @@ DWARFAbbreviationDeclaration::extract(DataExtractor Data,
     if (A && F) {
       Optional<int64_t> V;
       bool IsImplicitConst = (F == DW_FORM_implicit_const);
-      if (IsImplicitConst)
+      if (IsImplicitConst) {
         V = Data.getSLEB128(OffsetPtr);
-      else if (auto Size = DWARFFormValue::getFixedByteSize(F))
-        V = *Size;
-      AttributeSpecs.push_back(AttributeSpec(A, F, V));
-      if (IsImplicitConst)
+        AttributeSpecs.push_back(AttributeSpec(A, F, V));
         continue;
+      }
       // If this abbrevation still has a fixed byte size, then update the
       // FixedAttributeSize as needed.
-      if (FixedAttributeSize) {
-        if (V)
-          FixedAttributeSize->NumBytes += *V;
-        else {
-          switch (F) {
-          case DW_FORM_addr:
-            ++FixedAttributeSize->NumAddrs;
-            break;
-
-          case DW_FORM_ref_addr:
-            ++FixedAttributeSize->NumRefAddrs;
-            break;
-
-          case DW_FORM_strp:
-          case DW_FORM_GNU_ref_alt:
-          case DW_FORM_GNU_strp_alt:
-          case DW_FORM_line_strp:
-          case DW_FORM_sec_offset:
-          case DW_FORM_strp_sup:
-            ++FixedAttributeSize->NumDwarfOffsets;
-            break;
-
-          default:
-            // Indicate we no longer have a fixed byte size for this
-            // abbreviation by clearing the FixedAttributeSize optional value
-            // so it doesn't have a value.
-            FixedAttributeSize.reset();
-            break;
-          }
+      switch (F) {
+      case DW_FORM_addr:
+        if (FixedAttributeSize)
+          ++FixedAttributeSize->NumAddrs;
+        break;
+
+      case DW_FORM_ref_addr:
+        if (FixedAttributeSize)
+          ++FixedAttributeSize->NumRefAddrs;
+        break;
+
+      case DW_FORM_strp:
+      case DW_FORM_GNU_ref_alt:
+      case DW_FORM_GNU_strp_alt:
+      case DW_FORM_line_strp:
+      case DW_FORM_sec_offset:
+      case DW_FORM_strp_sup:
+        if (FixedAttributeSize)
+          ++FixedAttributeSize->NumDwarfOffsets;
+        break;
+
+      default:
+        // The form has a byte size that doesn't depend on Params.
+        // If it's a fixed size, keep track of it.
+        if (auto Size =
+                DWARFFormValue::getFixedByteSize(F, DWARFFormParams())) {
+          V = *Size;
+          if (FixedAttributeSize)
+            FixedAttributeSize->NumBytes += *V;
+          break;
         }
+        // Indicate we no longer have a fixed byte size for this
+        // abbreviation by clearing the FixedAttributeSize optional value
+        // so it doesn't have a value.
+        FixedAttributeSize.reset();
+        break;
       }
+      // Record this attribute and its fixed size if it has one.
+      AttributeSpecs.push_back(AttributeSpec(A, F, V));
     } else if (A == 0 && F == 0) {
       // We successfully reached the end of this abbreviation declaration
       // since both attribute and form are zero.
@@ -186,7 +192,8 @@ Optional<DWARFFormValue> DWARFAbbreviationDeclaration::getAttributeValue(
     if (auto FixedSize = Spec.getByteSize(U))
       Offset += *FixedSize;
     else
-      DWARFFormValue::skipValue(Spec.Form, DebugInfoData, &Offset, &U);
+      DWARFFormValue::skipValue(Spec.Form, DebugInfoData, &Offset,
+                                U.getFormParams());
     ++AttrIndex;
   }
   return None;
@@ -211,7 +218,8 @@ Optional<int64_t> DWARFAbbreviationDeclaration::AttributeSpec::getByteSize(
   if (ByteSizeOrValue)
     return ByteSizeOrValue;
   Optional<int64_t> S;
-  auto FixedByteSize = DWARFFormValue::getFixedByteSize(Form, &U);
+  auto FixedByteSize =
+      DWARFFormValue::getFixedByteSize(Form, U.getFormParams());
   if (FixedByteSize)
     S = *FixedByteSize;
   return S;

lib/DebugInfo/DWARF/DWARFDebugInfoEntry.cpp

@@ -59,7 +59,7 @@ bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint32_t *OffsetPtr,
       // Attribute byte size if fixed, just add the size to the offset.
       *OffsetPtr += *FixedSize;
     } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData,
-                                          OffsetPtr, &U)) {
+                                          OffsetPtr, U.getFormParams())) {
       // We failed to skip this attribute's value, restore the original offset
       // and return the failure status.
       *OffsetPtr = Offset;

lib/DebugInfo/DWARF/DWARFDebugLine.cpp

@@ -44,11 +44,11 @@ using ContentDescriptors = SmallVector<ContentDescriptor, 4>;
 DWARFDebugLine::Prologue::Prologue() { clear(); }
 
 void DWARFDebugLine::Prologue::clear() {
-  TotalLength = Version = PrologueLength = 0;
-  AddressSize = SegSelectorSize = 0;
+  TotalLength = PrologueLength = 0;
+  SegSelectorSize = 0;
   MinInstLength = MaxOpsPerInst = DefaultIsStmt = LineBase = LineRange = 0;
   OpcodeBase = 0;
-  IsDWARF64 = false;
+  FormParams = DWARFFormParams({0, 0, DWARF32});
   StandardOpcodeLengths.clear();
   IncludeDirectories.clear();
   FileNames.clear();
@@ -57,12 +57,13 @@ void DWARFDebugLine::Prologue::clear() {
 void DWARFDebugLine::Prologue::dump(raw_ostream &OS) const {
   OS << "Line table prologue:\n"
      << format("    total_length: 0x%8.8" PRIx64 "\n", TotalLength)
-     << format("         version: %u\n", Version)
-     << format(Version >= 5 ? "    address_size: %u\n" : "", AddressSize)
-     << format(Version >= 5 ? " seg_select_size: %u\n" : "", SegSelectorSize)
-     << format(" prologue_length: 0x%8.8" PRIx64 "\n", PrologueLength)
+     << format("         version: %u\n", getVersion());
+  if (getVersion() >= 5)
+    OS << format("    address_size: %u\n", getAddressSize())
+       << format(" seg_select_size: %u\n", SegSelectorSize);
+  OS << format(" prologue_length: 0x%8.8" PRIx64 "\n", PrologueLength)
      << format(" min_inst_length: %u\n", MinInstLength)
-     << format(Version >= 4 ? "max_ops_per_inst: %u\n" : "", MaxOpsPerInst)
+     << format(getVersion() >= 4 ? "max_ops_per_inst: %u\n" : "", MaxOpsPerInst)
      << format(" default_is_stmt: %u\n", DefaultIsStmt)
      << format("       line_base: %i\n", LineBase)
      << format("      line_range: %u\n", LineRange)
@@ -143,6 +144,7 @@ parseV5EntryFormat(DataExtractor DebugLineData, uint32_t *OffsetPtr,
 static bool
 parseV5DirFileTables(DataExtractor DebugLineData, uint32_t *OffsetPtr,
                      uint64_t EndPrologueOffset,
+                     const DWARFFormParams &FormParams,
                      std::vector<StringRef> &IncludeDirectories,
                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
   // Get the directory entry description.
@@ -165,7 +167,7 @@ parseV5DirFileTables(DataExtractor DebugLineData, uint32_t *OffsetPtr,
         IncludeDirectories.push_back(Value.getAsCString().getValue());
         break;
       default:
-        if (!Value.skipValue(DebugLineData, OffsetPtr, nullptr))
+        if (!Value.skipValue(DebugLineData, OffsetPtr, FormParams))
           return false;
       }
     }
@@ -217,24 +219,26 @@ bool DWARFDebugLine::Prologue::parse(DataExtractor DebugLineData,
   clear();
   TotalLength = DebugLineData.getU32(OffsetPtr);
   if (TotalLength == UINT32_MAX) {
-    IsDWARF64 = true;
+    FormParams.Format = dwarf::DWARF64;
     TotalLength = DebugLineData.getU64(OffsetPtr);
-  } else if (TotalLength > 0xffffff00) {
+  } else if (TotalLength >= 0xffffff00) {
     return false;
   }
-  Version = DebugLineData.getU16(OffsetPtr);
-  if (Version < 2)
+  FormParams.Version = DebugLineData.getU16(OffsetPtr);
+  if (getVersion() < 2)
     return false;
 
-  if (Version >= 5) {
-    AddressSize = DebugLineData.getU8(OffsetPtr);
+  if (getVersion() >= 5) {
+    FormParams.AddrSize = DebugLineData.getU8(OffsetPtr);
+    assert(getAddressSize() == DebugLineData.getAddressSize() &&
+           "Line table header and data extractor disagree");
     SegSelectorSize = DebugLineData.getU8(OffsetPtr);
   }
 
   PrologueLength = DebugLineData.getUnsigned(OffsetPtr, sizeofPrologueLength());
   const uint64_t EndPrologueOffset = PrologueLength + *OffsetPtr;
   MinInstLength = DebugLineData.getU8(OffsetPtr);
-  if (Version >= 4)
+  if (getVersion() >= 4)
     MaxOpsPerInst = DebugLineData.getU8(OffsetPtr);
   DefaultIsStmt = DebugLineData.getU8(OffsetPtr);
   LineBase = DebugLineData.getU8(OffsetPtr);
@@ -247,9 +251,9 @@ bool DWARFDebugLine::Prologue::parse(DataExtractor DebugLineData,
     StandardOpcodeLengths.push_back(OpLen);
   }
 
-  if (Version >= 5) {
+  if (getVersion() >= 5) {
     if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                              IncludeDirectories, FileNames)) {
+                              getFormParams(), IncludeDirectories, FileNames)) {
       fprintf(stderr,
               "warning: parsing line table prologue at 0x%8.8" PRIx64
               " found an invalid directory or file table description at"

lib/DebugInfo/DWARF/DWARFFormValue.cpp

@@ -59,48 +59,13 @@ static const DWARFFormValue::FormClass DWARF4FormClasses[] = {
     DWARFFormValue::FC_Flag,          // 0x19 DW_FORM_flag_present
 };
 
-namespace {
-
-/// A helper class that can be used in DWARFFormValue.cpp functions that need
-/// to know the byte size of DW_FORM values that vary in size depending on the
-/// DWARF version, address byte size, or DWARF32 or DWARF64.
-class FormSizeHelper {
-  uint16_t Version;
-  uint8_t AddrSize;
-  llvm::dwarf::DwarfFormat Format;
-
-public:
-  FormSizeHelper(uint16_t V, uint8_t A, llvm::dwarf::DwarfFormat F)
-      : Version(V), AddrSize(A), Format(F) {}
-
-  uint8_t getAddressByteSize() const { return AddrSize; }
-
-  uint8_t getRefAddrByteSize() const {
-    if (Version == 2)
-      return AddrSize;
-    return getDwarfOffsetByteSize();
-  }
-
-  uint8_t getDwarfOffsetByteSize() const {
-    switch (Format) {
-    case dwarf::DwarfFormat::DWARF32:
-      return 4;
-    case dwarf::DwarfFormat::DWARF64:
-      return 8;
-    }
-    llvm_unreachable("Invalid Format value");
-  }
-};
-
-} // end anonymous namespace
-
-template <class T>
-static Optional<uint8_t> getFixedByteSize(dwarf::Form Form, const T *U) {
+Optional<uint8_t>
+DWARFFormValue::getFixedByteSize(dwarf::Form Form,
+                                 const DWARFFormParams &Params) {
   switch (Form) {
   case DW_FORM_addr:
-    if (U)
-      return U->getAddressByteSize();
-    return None;
+    assert(Params.Version && Params.AddrSize && "Invalid Params for form");
+    return Params.AddrSize;
 
   case DW_FORM_block:          // ULEB128 length L followed by L bytes.
   case DW_FORM_block1:         // 1 byte length L followed by L bytes.
@@ -121,9 +86,8 @@ static Optional<uint8_t> getFixedByteSize(dwarf::Form Form, const T *U) {
     return None;
 
   case DW_FORM_ref_addr:
-    if (U)
-      return U->getRefAddrByteSize();
-    return None;
+    assert(Params.Version && Params.AddrSize && "Invalid Params for form");
+    return Params.getRefAddrByteSize();
 
   case DW_FORM_flag:
   case DW_FORM_data1:
@@ -154,9 +118,8 @@ static Optional<uint8_t> getFixedByteSize(dwarf::Form Form, const T *U) {
   case DW_FORM_line_strp:
   case DW_FORM_sec_offset:
   case DW_FORM_strp_sup:
-    if (U)
-      return U->getDwarfOffsetByteSize();
-    return None;
+    assert(Params.Version && Params.AddrSize && "Invalid Params for form");
+    return Params.getDwarfOffsetByteSize();
 
   case DW_FORM_data8:
   case DW_FORM_ref8:
@@ -181,9 +144,9 @@ static Optional<uint8_t> getFixedByteSize(dwarf::Form Form, const T *U) {
   return None;
 }
 
-template <class T>
-static bool skipFormValue(dwarf::Form Form, const DataExtractor &DebugInfoData,
-                          uint32_t *OffsetPtr, const T *U) {
+bool DWARFFormValue::skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
+                               uint32_t *OffsetPtr,
+                               const DWARFFormParams &Params) {
   bool Indirect = false;
   do {
     switch (Form) {
@@ -243,7 +206,8 @@ static bool skipFormValue(dwarf::Form Form, const DataExtractor &DebugInfoData,
     case DW_FORM_line_strp:
     case DW_FORM_GNU_ref_alt:
     case DW_FORM_GNU_strp_alt:
-      if (Optional<uint8_t> FixedSize = ::getFixedByteSize(Form, U)) {
+      if (Optional<uint8_t> FixedSize =
+              DWARFFormValue::getFixedByteSize(Form, Params)) {
         *OffsetPtr += *FixedSize;
         return true;
       }
@@ -277,19 +241,6 @@ static bool skipFormValue(dwarf::Form Form, const DataExtractor &DebugInfoData,
   return true;
 }
 
-Optional<uint8_t> DWARFFormValue::getFixedByteSize(dwarf::Form Form,
-                                                   const DWARFUnit *U) {
-  return ::getFixedByteSize(Form, U);
-}
-
-Optional<uint8_t>
-DWARFFormValue::getFixedByteSize(dwarf::Form Form, uint16_t Version,
-                                 uint8_t AddrSize,
-                                 llvm::dwarf::DwarfFormat Format) {
-  FormSizeHelper FSH(Version, AddrSize, Format);
-  return ::getFixedByteSize(Form, &FSH);
-}
-
 bool DWARFFormValue::isFormClass(DWARFFormValue::FormClass FC) const {
   // First, check DWARF4 form classes.
   if (Form < makeArrayRef(DWARF4FormClasses).size() &&
@@ -448,24 +399,6 @@ bool DWARFFormValue::extractValue(const DataExtractor &Data,
   return true;
 }
 
-bool DWARFFormValue::skipValue(DataExtractor DebugInfoData, uint32_t *OffsetPtr,
-                               const DWARFUnit *U) const {
-  return DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, U);
-}
-
-bool DWARFFormValue::skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
-                               uint32_t *OffsetPtr, const DWARFUnit *U) {
-  return skipFormValue(Form, DebugInfoData, OffsetPtr, U);
-}
-
-bool DWARFFormValue::skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
-                               uint32_t *OffsetPtr, uint16_t Version,
-                               uint8_t AddrSize,
-                               llvm::dwarf::DwarfFormat Format) {
-  FormSizeHelper FSH(Version, AddrSize, Format);
-  return skipFormValue(Form, DebugInfoData, OffsetPtr, &FSH);
-}
-
 void DWARFFormValue::dump(raw_ostream &OS) const {
   uint64_t UValue = Value.uval;
   bool CURelativeOffset = false;

lib/DebugInfo/DWARF/DWARFUnit.cpp

@@ -62,11 +62,13 @@ DWARFUnit::~DWARFUnit() = default;
 
 bool DWARFUnit::getAddrOffsetSectionItem(uint32_t Index,
                                                 uint64_t &Result) const {
-  uint32_t Offset = AddrOffsetSectionBase + Index * AddrSize;
-  if (AddrOffsetSection->Data.size() < Offset + AddrSize)
+  uint32_t Offset = AddrOffsetSectionBase + Index * getAddressByteSize();
+  if (AddrOffsetSection->Data.size() < Offset + getAddressByteSize())
     return false;
-  DataExtractor DA(AddrOffsetSection->Data, isLittleEndian, AddrSize);
-  Result = getRelocatedValue(DA, AddrSize, &Offset, &AddrOffsetSection->Relocs);
+  DataExtractor DA(AddrOffsetSection->Data, isLittleEndian,
+                   getAddressByteSize());
+  Result = getRelocatedValue(DA, getAddressByteSize(), &Offset,
+                             &AddrOffsetSection->Relocs);
   return true;
 }
 
@@ -92,15 +94,17 @@ uint64_t DWARFUnit::getStringOffsetSectionRelocation(uint32_t Index) const {
 
 bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
   Length = debug_info.getU32(offset_ptr);
-  Version = debug_info.getU16(offset_ptr);
+  // FIXME: Support DWARF64.
+  FormParams.Format = DWARF32;
+  FormParams.Version = debug_info.getU16(offset_ptr);
   uint64_t AbbrOffset;
-  if (Version >= 5) {
+  if (FormParams.Version >= 5) {
     UnitType = debug_info.getU8(offset_ptr);
-    AddrSize = debug_info.getU8(offset_ptr);
+    FormParams.AddrSize = debug_info.getU8(offset_ptr);
     AbbrOffset = debug_info.getU32(offset_ptr);
   } else {
     AbbrOffset = debug_info.getU32(offset_ptr);
-    AddrSize = debug_info.getU8(offset_ptr);
+    FormParams.AddrSize = debug_info.getU8(offset_ptr);
   }
   if (IndexEntry) {
     if (AbbrOffset)
@@ -115,14 +119,14 @@ bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
   }
 
   bool LengthOK = debug_info.isValidOffset(getNextUnitOffset() - 1);
-  bool VersionOK = DWARFContext::isSupportedVersion(Version);
-  bool AddrSizeOK = AddrSize == 4 || AddrSize == 8;
+  bool VersionOK = DWARFContext::isSupportedVersion(getVersion());
+  bool AddrSizeOK = getAddressByteSize() == 4 || getAddressByteSize() == 8;
 
   if (!LengthOK || !VersionOK || !AddrSizeOK)
     return false;
 
   // Keep track of the highest DWARF version we encounter across all units.
-  Context.setMaxVersionIfGreater(Version);
+  Context.setMaxVersionIfGreater(getVersion());
 
   Abbrevs = Abbrev->getAbbreviationDeclarationSet(AbbrOffset);
   return Abbrevs != nullptr;
@@ -148,7 +152,8 @@ bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
                                         DWARFDebugRangeList &RangeList) const {
   // Require that compile unit is extracted.
   assert(!DieArray.empty());
-  DataExtractor RangesData(RangeSection->Data, isLittleEndian, AddrSize);
+  DataExtractor RangesData(RangeSection->Data, isLittleEndian,
+                           getAddressByteSize());
   uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
   return RangeList.extract(RangesData, &ActualRangeListOffset,
                            RangeSection->Relocs);
@@ -157,9 +162,8 @@ bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
 void DWARFUnit::clear() {
   Offset = 0;
   Length = 0;
-  Version = 0;
   Abbrevs = nullptr;
-  AddrSize = 0;
+  FormParams = DWARFFormParams({0, 0, DWARF32});
   BaseAddr = 0;
   RangeSectionBase = 0;
   AddrOffsetSectionBase = 0;

tools/dsymutil/DwarfLinker.cpp

@@ -2063,10 +2063,12 @@ getAttributeOffsets(const DWARFAbbreviationDeclaration *Abbrev, unsigned Idx,
   DataExtractor Data = Unit.getDebugInfoExtractor();
 
   for (unsigned i = 0; i < Idx; ++i)
-    DWARFFormValue::skipValue(Abbrev->getFormByIndex(i), Data, &Offset, &Unit);
+    DWARFFormValue::skipValue(Abbrev->getFormByIndex(i), Data, &Offset,
+                              Unit.getFormParams());
 
   uint32_t End = Offset;
-  DWARFFormValue::skipValue(Abbrev->getFormByIndex(Idx), Data, &End, &Unit);
+  DWARFFormValue::skipValue(Abbrev->getFormByIndex(Idx), Data, &End,
+                            Unit.getFormParams());
 
   return std::make_pair(Offset, End);
 }
@@ -2219,7 +2221,8 @@ void DwarfLinker::keepDIEAndDependencies(RelocationManager &RelocMgr,
     DWARFFormValue Val(AttrSpec.Form);
 
     if (!Val.isFormClass(DWARFFormValue::FC_Reference)) {
-      DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, &Unit);
+      DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
+                                Unit.getFormParams());
       continue;
     }
 
@@ -2779,7 +2782,8 @@ DIE *DwarfLinker::DIECloner::cloneDIE(
   for (const auto &AttrSpec : Abbrev->attributes()) {
     if (shouldSkipAttribute(AttrSpec, Die->getTag(), Info.InDebugMap,
                             Flags & TF_SkipPC, Flags & TF_InFunctionScope)) {
-      DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset, &U);
+      DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
+                                U.getFormParams());
       // FIXME: dsymutil-classic keeps the old abbreviation around
       // even if it's not used. We can remove this (and the copyAbbrev
       // helper) as soon as bit-for-bit compatibility is not a goal anymore.
@@ -3077,7 +3081,7 @@ void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
   // prologue over and that works because we act as both producer and
   // consumer. It would be nicer to have a real configurable line
   // table emitter.
-  if (LineTable.Prologue.Version != 2 ||
+  if (LineTable.Prologue.getVersion() != 2 ||
       LineTable.Prologue.DefaultIsStmt != DWARF2_LINE_DEFAULT_IS_STMT ||
       LineTable.Prologue.OpcodeBase > 13)
     reportWarning("line table parameters mismatch. Cannot emit.");

tools/llvm-dwp/llvm-dwp.cpp

@@ -182,8 +182,8 @@ static Expected<CompileUnitIdentifiers> getCUIdentifiers(StringRef Abbrev,
       ID.Signature = InfoData.getU64(&Offset);
       break;
     default:
-      DWARFFormValue::skipValue(Form, InfoData, &Offset, Version, AddrSize,
-                                Format);
+      DWARFFormValue::skipValue(Form, InfoData, &Offset,
+                                DWARFFormParams({Version, AddrSize, Format}));
     }
   }
   return ID;

unittests/DebugInfo/DWARF/DWARFFormValueTest.cpp

@@ -23,43 +23,52 @@ namespace {
 TEST(DWARFFormValue, FixedFormSizes) {
   Optional<uint8_t> RefSize;
   Optional<uint8_t> AddrSize;
+
   // Test 32 bit DWARF version 2 with 4 byte addresses.
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 2, 4, DWARF32);
-  AddrSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 2, 4, DWARF32);
+  DWARFFormParams Params_2_4_32 = {2, 4, DWARF32};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_2_4_32);
+  AddrSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_2_4_32);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_TRUE(AddrSize.hasValue());
   EXPECT_EQ(*RefSize, *AddrSize);
 
   // Test 32 bit DWARF version 2 with 8 byte addresses.
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 2, 8, DWARF32);
-  AddrSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 2, 8, DWARF32);
+  DWARFFormParams Params_2_8_32 = {2, 8, DWARF32};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_2_8_32);
+  AddrSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_2_8_32);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_TRUE(AddrSize.hasValue());
   EXPECT_EQ(*RefSize, *AddrSize);
 
   // DW_FORM_ref_addr is 4 bytes in DWARF 32 in DWARF version 3 and beyond.
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 3, 4, DWARF32);
+  DWARFFormParams Params_3_4_32 = {3, 4, DWARF32};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_3_4_32);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_EQ(*RefSize, 4);
 
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 4, 4, DWARF32);
+  DWARFFormParams Params_4_4_32 = {4, 4, DWARF32};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_4_4_32);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_EQ(*RefSize, 4);
 
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 5, 4, DWARF32);
+  DWARFFormParams Params_5_4_32 = {5, 4, DWARF32};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_5_4_32);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_EQ(*RefSize, 4);
 
   // DW_FORM_ref_addr is 8 bytes in DWARF 64 in DWARF version 3 and beyond.
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 3, 8, DWARF64);
+  DWARFFormParams Params_3_8_64 = {3, 8, DWARF64};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_3_8_64);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_EQ(*RefSize, 8);
 
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 4, 8, DWARF64);
+  DWARFFormParams Params_4_8_64 = {4, 8, DWARF64};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_4_8_64);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_EQ(*RefSize, 8);
 
-  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, 5, 8, DWARF64);
+  DWARFFormParams Params_5_8_64 = {5, 8, DWARF64};
+  RefSize = DWARFFormValue::getFixedByteSize(DW_FORM_ref_addr, Params_5_8_64);
   EXPECT_TRUE(RefSize.hasValue());
   EXPECT_EQ(*RefSize, 8);
 }