[DWARFv5] Support DW_FORM_strp in the .debug_line header.

Supporting this form in .debug_line.dwo will be done as a follow-up.

Differential Revision: https://reviews.llvm.org/D33155

llvm-svn: 317607

lld/ELF/InputFiles.cpp

@@ -77,8 +77,10 @@ template <class ELFT> void ObjFile<ELFT>::initializeDwarf() {
   // The second parameter is offset in .debug_line section
   // for compilation unit (CU) of interest. We have only one
   // CU (object file), so offset is always 0.
+  // FIXME: Provide the associated DWARFUnit if there is one.  DWARF v5
+  // needs it in order to find indirect strings.
   const DWARFDebugLine::LineTable *LT =
-      DwarfLine->getOrParseLineTable(LineData, 0);
+      DwarfLine->getOrParseLineTable(LineData, 0, nullptr);
 
   // Return if there is no debug information about CU available.
   if (!Dwarf.getNumCompileUnits())

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h

@@ -22,6 +22,7 @@
 
 namespace llvm {
 
+class DWARFUnit;
 class raw_ostream;
 
 class DWARFDebugLine {
@@ -95,7 +96,8 @@ public:
 
     void clear();
     void dump(raw_ostream &OS) const;
-    bool parse(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr);
+    bool parse(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
+               const DWARFUnit *U = nullptr);
   };
 
   /// Standard .debug_line state machine structure.
@@ -218,7 +220,7 @@ public:
 
     /// Parse prologue and all rows.
     bool parse(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
-               raw_ostream *OS = nullptr);
+               const DWARFUnit *U, raw_ostream *OS = nullptr);
 
     using RowVector = std::vector<Row>;
     using RowIter = RowVector::const_iterator;
@@ -236,7 +238,7 @@ public:
 
   const LineTable *getLineTable(uint32_t Offset) const;
   const LineTable *getOrParseLineTable(const DWARFDataExtractor &DebugLineData,
-                                       uint32_t Offset);
+                                       uint32_t Offset, const DWARFUnit *U);
 
 private:
   struct ParsingState {

llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h

@@ -104,16 +104,12 @@ public:
   const DWARFUnit *getUnit() const { return U; }
   void dump(raw_ostream &OS, DIDumpOptions DumpOpts = DIDumpOptions()) const;
 
-  /// Extracts a value in \p Data at offset \p *OffsetPtr.
+  /// Extracts a value in \p Data at offset \p *OffsetPtr. The information
-  ///
+  /// in \p FormParams is needed to interpret some forms. The optional
-  /// The passed DWARFUnit is allowed to be nullptr, in which case some
+  /// \p Unit allows extracting information if the form refers to other
-  /// kind of forms that depend on Unit information are disallowed.
+  /// sections (e.g., .debug_str).
-  /// \param Data The DWARFDataExtractor to use.
-  /// \param OffsetPtr The offset within \p Data where the data starts.
-  /// \param U The optional DWARFUnit supplying information for some forms.
-  /// \returns whether the extraction succeeded.
   bool extractValue(const DWARFDataExtractor &Data, uint32_t *OffsetPtr,
-                    const DWARFUnit *U);
+                    DWARFFormParams FormParams, const DWARFUnit *U = nullptr);
 
   bool isInlinedCStr() const {
     return Value.data != nullptr && Value.data == (const uint8_t *)Value.cstr;

llvm/lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp

@@ -184,7 +184,7 @@ Optional<DWARFFormValue> DWARFAbbreviationDeclaration::getAttributeValue(
         FormValue.setSValue(Spec.getImplicitConstValue());
         return FormValue;
       }
-      if (FormValue.extractValue(DebugInfoData, &Offset, &U))
+      if (FormValue.extractValue(DebugInfoData, &Offset, U.getFormParams(), &U))
         return FormValue;
     }
     // March Offset along until we get to the attribute we want.

llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp

@@ -90,10 +90,11 @@ std::pair<uint32_t, dwarf::Tag>
 DWARFAcceleratorTable::readAtoms(uint32_t &HashDataOffset) {
   uint32_t DieOffset = dwarf::DW_INVALID_OFFSET;
   dwarf::Tag DieTag = dwarf::DW_TAG_null;
+  DWARFFormParams FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
 
   for (auto Atom : getAtomsDesc()) {
     DWARFFormValue FormValue(Atom.second);
-    FormValue.extractValue(AccelSection, &HashDataOffset, NULL);
+    FormValue.extractValue(AccelSection, &HashDataOffset, FormParams);
     switch (Atom.first) {
     case dwarf::DW_ATOM_die_offset:
       DieOffset = *FormValue.getAsUnsignedConstant();
@@ -145,6 +146,7 @@ LLVM_DUMP_METHOD void DWARFAcceleratorTable::dump(raw_ostream &OS) const {
   uint32_t Offset = sizeof(Hdr) + Hdr.HeaderDataLength;
   unsigned HashesBase = Offset + Hdr.NumBuckets * 4;
   unsigned OffsetsBase = HashesBase + Hdr.NumHashes * 4;
+  DWARFFormParams FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
 
   for (unsigned Bucket = 0; Bucket < Hdr.NumBuckets; ++Bucket) {
     unsigned Index = AccelSection.getU32(&Offset);
@@ -181,7 +183,7 @@ LLVM_DUMP_METHOD void DWARFAcceleratorTable::dump(raw_ostream &OS) const {
           unsigned i = 0;
           for (auto &Atom : AtomForms) {
             OS << format("{Atom[%d]: ", i++);
-            if (Atom.extractValue(AccelSection, &DataOffset, nullptr))
+            if (Atom.extractValue(AccelSection, &DataOffset, FormParams))
               Atom.dump(OS);
             else
               OS << "Error extracting the value";
@@ -216,8 +218,10 @@ void DWARFAcceleratorTable::ValueIterator::Next() {
     NumData = 0;
     return;
   }
+  DWARFFormParams FormParams = {AccelTable->Hdr.Version, 0,
+                                dwarf::DwarfFormat::DWARF32};
   for (auto &Atom : AtomForms)
-    Atom.extractValue(AccelSection, &DataOffset, nullptr);
+    Atom.extractValue(AccelSection, &DataOffset, FormParams);
   ++Data;
 }
 

llvm/lib/DebugInfo/DWARF/DWARFContext.cpp

@@ -329,9 +329,9 @@ void DWARFContext::dump(
         // representation.
         OS << "debug_line[" << format("0x%8.8x", Offset) << "]\n";
         if (DumpOpts.Verbose) {
-          LineTable.parse(lineData, &Offset, &OS);
+          LineTable.parse(lineData, &Offset, &*CU, &OS);
         } else {
-          LineTable.parse(lineData, &Offset);
+          LineTable.parse(lineData, &Offset, &*CU);
           LineTable.dump(OS);
         }
       }
@@ -349,7 +349,7 @@ void DWARFContext::dump(
     DWARFDataExtractor lineData(*DObj, DObj->getLineDWOSection(),
                                 isLittleEndian(), savedAddressByteSize);
     DWARFDebugLine::LineTable LineTable;
-    while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
+    while (LineTable.Prologue.parse(lineData, &stmtOffset, nullptr)) {
       LineTable.dump(OS);
       LineTable.clear();
     }
@@ -681,7 +681,7 @@ DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   // We have to parse it first.
   DWARFDataExtractor lineData(*DObj, U->getLineSection(), isLittleEndian(),
                               U->getAddressByteSize());
-  return Line->getOrParseLineTable(lineData, stmtOffset);
+  return Line->getOrParseLineTable(lineData, stmtOffset, U);
 }
 
 void DWARFContext::parseCompileUnits() {

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

@@ -144,7 +144,7 @@ parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
 static bool
 parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
                      uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
-                     const DWARFFormParams &FormParams,
+                     const DWARFFormParams &FormParams, const DWARFUnit *U,
                      std::vector<StringRef> &IncludeDirectories,
                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
   // Get the directory entry description.
@@ -162,7 +162,7 @@ parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
       DWARFFormValue Value(Descriptor.Form);
       switch (Descriptor.Type) {
       case DW_LNCT_path:
-        if (!Value.extractValue(DebugLineData, OffsetPtr, nullptr))
+        if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, U))
           return false;
         IncludeDirectories.push_back(Value.getAsCString().getValue());
         break;
@@ -187,7 +187,7 @@ parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
     DWARFDebugLine::FileNameEntry FileEntry;
     for (auto Descriptor : FileDescriptors) {
       DWARFFormValue Value(Descriptor.Form);
-      if (!Value.extractValue(DebugLineData, OffsetPtr, nullptr))
+      if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, U))
         return false;
       switch (Descriptor.Type) {
       case DW_LNCT_path:
@@ -213,7 +213,7 @@ parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
 }
 
 bool DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
-                                     uint32_t *OffsetPtr) {
+                                     uint32_t *OffsetPtr, const DWARFUnit *U) {
   const uint64_t PrologueOffset = *OffsetPtr;
 
   clear();
@@ -253,7 +253,8 @@ bool DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
 
   if (getVersion() >= 5) {
     if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                              getFormParams(), IncludeDirectories, FileNames)) {
+                              getFormParams(), U, IncludeDirectories,
+                              FileNames)) {
       fprintf(stderr,
               "warning: parsing line table prologue at 0x%8.8" PRIx64
               " found an invalid directory or file table description at"
@@ -382,24 +383,25 @@ DWARFDebugLine::getLineTable(uint32_t Offset) const {
 
 const DWARFDebugLine::LineTable *
 DWARFDebugLine::getOrParseLineTable(const DWARFDataExtractor &DebugLineData,
-                                    uint32_t Offset) {
+                                    uint32_t Offset, const DWARFUnit *U) {
   std::pair<LineTableIter, bool> Pos =
       LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
   LineTable *LT = &Pos.first->second;
   if (Pos.second) {
-    if (!LT->parse(DebugLineData, &Offset))
+    if (!LT->parse(DebugLineData, &Offset, U))
       return nullptr;
   }
   return LT;
 }
 
 bool DWARFDebugLine::LineTable::parse(const DWARFDataExtractor &DebugLineData,
-                                      uint32_t *OffsetPtr, raw_ostream *OS) {
+                                      uint32_t *OffsetPtr, const DWARFUnit *U,
+                                      raw_ostream *OS) {
   const uint32_t DebugLineOffset = *OffsetPtr;
 
   clear();
 
-  if (!Prologue.parse(DebugLineData, OffsetPtr)) {
+  if (!Prologue.parse(DebugLineData, OffsetPtr, U)) {
     // Restore our offset and return false to indicate failure!
     *OffsetPtr = DebugLineOffset;
     return false;

llvm/lib/DebugInfo/DWARF/DWARFDie.cpp

@@ -208,7 +208,8 @@ static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
   DWARFUnit *U = Die.getDwarfUnit();
   DWARFFormValue formValue(Form);
 
-  if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr, U))
+  if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr,
+                              U->getFormParams(), U))
     return;
 
   OS << "\t(";
@@ -550,7 +551,7 @@ void DWARFDie::attribute_iterator::updateForIndex(
     auto U = Die.getDwarfUnit();
     assert(U && "Die must have valid DWARF unit");
     bool b = AttrValue.Value.extractValue(U->getDebugInfoExtractor(),
-                                          &ParseOffset, U);
+                                          &ParseOffset, U->getFormParams(), U);
     (void)b;
     assert(b && "extractValue cannot fail on fully parsed DWARF");
     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;

llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp

@@ -276,7 +276,8 @@ bool DWARFFormValue::isFormClass(DWARFFormValue::FormClass FC) const {
 }
 
 bool DWARFFormValue::extractValue(const DWARFDataExtractor &Data,
-                                  uint32_t *OffsetPtr, const DWARFUnit *CU) {
+                                  uint32_t *OffsetPtr, DWARFFormParams FP,
+                                  const DWARFUnit *CU) {
   U = CU;
   bool Indirect = false;
   bool IsBlock = false;
@@ -288,10 +289,8 @@ bool DWARFFormValue::extractValue(const DWARFDataExtractor &Data,
     switch (Form) {
     case DW_FORM_addr:
     case DW_FORM_ref_addr: {
-      if (!U)
+      uint16_t Size =
-        return false;
+          (Form == DW_FORM_addr) ? FP.AddrSize : FP.getRefAddrByteSize();
-      uint16_t Size = (Form == DW_FORM_addr) ? U->getAddressByteSize()
-                                             : U->getRefAddrByteSize();
       Value.uval = Data.getRelocatedValue(Size, OffsetPtr, &Value.SectionIndex);
       break;
     }
@@ -360,10 +359,8 @@ bool DWARFFormValue::extractValue(const DWARFDataExtractor &Data,
     case DW_FORM_GNU_strp_alt:
     case DW_FORM_line_strp:
     case DW_FORM_strp_sup: {
-      if (!U)
-        return false;
       Value.uval =
-          Data.getRelocatedValue(U->getDwarfOffsetByteSize(), OffsetPtr);
+          Data.getRelocatedValue(FP.getDwarfOffsetByteSize(), OffsetPtr);
       break;
     }
     case DW_FORM_flag_present:

llvm/test/DebugInfo/Inputs/dwarfdump-header.s

@@ -15,6 +15,10 @@ str_CU_5:
         .asciz "V5_compile_unit"
 str_TU_4:
         .asciz "V4_type_unit"
+str_LT_5a:
+        .asciz "Directory5a"
+str_LT_5b:
+        .asciz "Directory5b"
 
         .section .debug_str.dwo,"MS",@progbits,1
 dwo_TU_5:
@@ -227,11 +231,11 @@ LH_5_params:
         # Directory table format
         .byte   1               # One element per directory entry
         .byte   1               # DW_LNCT_path
-        .byte   0x08            # DW_FORM_string
+        .byte   0x0e            # DW_FORM_strp (-> .debug_str)
         # Directory table entries
         .byte   2               # Two directories
-        .asciz "Directory5a"
+        .long   str_LT_5a
-        .asciz "Directory5b"
+        .long   str_LT_5b
         # File table format
         .byte   4               # Four elements per file entry
         .byte   1               # DW_LNCT_path

llvm/tools/dsymutil/DwarfLinker.cpp

@@ -2366,7 +2366,7 @@ void DwarfLinker::keepDIEAndDependencies(RelocationManager &RelocMgr,
       continue;
     }
 
-    Val.extractValue(Data, &Offset, &Unit);
+    Val.extractValue(Data, &Offset, Unit.getFormParams(), &Unit);
     CompileUnit *ReferencedCU;
     if (auto RefDie =
             resolveDIEReference(*this, Units, Val, Unit, Die, ReferencedCU)) {
@@ -2965,7 +2965,7 @@ DIE *DwarfLinker::DIECloner::cloneDIE(
 
     DWARFFormValue Val(AttrSpec.Form);
     uint32_t AttrSize = Offset;
-    Val.extractValue(Data, &Offset, &U);
+    Val.extractValue(Data, &Offset, U.getFormParams(), &U);
     AttrSize = Offset - AttrSize;
 
     OutOffset +=
@@ -3158,7 +3158,7 @@ void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
   DWARFDataExtractor LineExtractor(
       OrigDwarf.getDWARFObj(), OrigDwarf.getDWARFObj().getLineSection(),
       OrigDwarf.isLittleEndian(), Unit.getOrigUnit().getAddressByteSize());
-  LineTable.parse(LineExtractor, &StmtOffset);
+  LineTable.parse(LineExtractor, &StmtOffset, &Unit.getOrigUnit());
 
   // This vector is the output line table.
   std::vector<DWARFDebugLine::Row> NewRows;

llvm/unittests/DebugInfo/DWARF/DWARFFormValueTest.cpp

@@ -99,7 +99,7 @@ DWARFFormValue createDataXFormValue(dwarf::Form Form, RawTypeT Value) {
   DWARFFormValue Result(Form);
   DWARFDataExtractor Data(StringRef(Raw, sizeof(RawTypeT)),
                           sys::IsLittleEndianHost, sizeof(void *));
-  Result.extractValue(Data, &Offset, nullptr);
+  Result.extractValue(Data, &Offset, {0, 0, dwarf::DwarfFormat::DWARF32});
   return Result;
 }
 
@@ -110,7 +110,7 @@ DWARFFormValue createULEBFormValue(uint64_t Value) {
   uint32_t Offset = 0;
   DWARFFormValue Result(DW_FORM_udata);
   DWARFDataExtractor Data(OS.str(), sys::IsLittleEndianHost, sizeof(void *));
-  Result.extractValue(Data, &Offset, nullptr);
+  Result.extractValue(Data, &Offset, {0, 0, dwarf::DwarfFormat::DWARF32});
   return Result;
 }
 
@@ -121,7 +121,7 @@ DWARFFormValue createSLEBFormValue(int64_t Value) {
   uint32_t Offset = 0;
   DWARFFormValue Result(DW_FORM_sdata);
   DWARFDataExtractor Data(OS.str(), sys::IsLittleEndianHost, sizeof(void *));
-  Result.extractValue(Data, &Offset, nullptr);
+  Result.extractValue(Data, &Offset, {0, 0, dwarf::DwarfFormat::DWARF32});
   return Result;
 }