Revert "DWARFVerifier: Check "completeness" of .debug_names section"

The new verifier check has found an error in the
debug-names-name-collisions.ll test on the PS4 bot:

error: Name Index @ 0x0: Entry @ 0xdc: mismatched Name of DIE @ 0x23: index - _ZN3foo3fooE; debug_info - foo.

Reverting while I investigate whether this is a bug in the verifier or
the generator.

This reverts commit r331868.

llvm-svn: 331869

2 files changed, 2 insertions, 177 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp b/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
index 1fa3bc09f4b..9d1d0708e08 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
@@ -770,11 +770,6 @@ llvm::Error DWARFDebugNames::extract() {
   return Error::success();
 }
 
-iterator_range<DWARFDebugNames::ValueIterator>
-DWARFDebugNames::NameIndex::equal_range(StringRef Key) const {
-  return make_range(ValueIterator(*this, Key), ValueIterator());
-}
-
 LLVM_DUMP_METHOD void DWARFDebugNames::dump(raw_ostream &OS) const {
   ScopedPrinter W(OS);
   for (const NameIndex &NI : NameIndices)
@@ -849,44 +844,20 @@ void DWARFDebugNames::ValueIterator::next() {
   if (getEntryAtCurrentOffset())
     return;
 
-  // If we're a local iterator, we're done.
-  if (IsLocal) {
-    setEnd();
-    return;
-  }
-
-  // Otherwise, try the next index.
+  // Try the next Name Index.
   ++CurrentIndex;
   searchFromStartOfCurrentIndex();
 }
 
 DWARFDebugNames::ValueIterator::ValueIterator(const DWARFDebugNames &AccelTable,
                                               StringRef Key)
-    : CurrentIndex(AccelTable.NameIndices.begin()), IsLocal(false), Key(Key) {
+    : CurrentIndex(AccelTable.NameIndices.begin()), Key(Key) {
   searchFromStartOfCurrentIndex();
 }
 
-DWARFDebugNames::ValueIterator::ValueIterator(
-    const DWARFDebugNames::NameIndex &NI, StringRef Key)
-    : CurrentIndex(&NI), IsLocal(true), Key(Key) {
-  if (!findInCurrentIndex())
-    setEnd();
-}
-
 iterator_range<DWARFDebugNames::ValueIterator>
 DWARFDebugNames::equal_range(StringRef Key) const {
   if (NameIndices.empty())
     return make_range(ValueIterator(), ValueIterator());
   return make_range(ValueIterator(*this, Key), ValueIterator());
 }
-
-const DWARFDebugNames::NameIndex *
-DWARFDebugNames::getCUNameIndex(uint32_t CUOffset) {
-  if (CUToNameIndex.size() == 0 && NameIndices.size() > 0) {
-    for (const auto &NI : *this) {
-      for (uint32_t CU = 0; CU < NI.getCUCount(); ++CU)
-        CUToNameIndex.try_emplace(NI.getCUOffset(CU), &NI);
-    }
-  }
-  return CUToNameIndex.lookup(CUOffset);
-}
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index 91e5cfede29..ba7aef37eac 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -1122,7 +1122,6 @@ DWARFVerifier::verifyNameIndexEntries(const DWARFDebugNames::NameIndex &NI,
                          "of DIE @ {2:x}: index - {3}; debug_info - {4}.\n",
                          NI.getUnitOffset(), EntryID, DIEOffset, Str,
                          make_range(EntryNames.begin(), EntryNames.end()));
-      ++NumErrors;
     }
   }
   handleAllErrors(EntryOr.takeError(),
@@ -1143,141 +1142,6 @@ DWARFVerifier::verifyNameIndexEntries(const DWARFDebugNames::NameIndex &NI,
   return NumErrors;
 }
 
-static bool isVariableIndexable(const DWARFDie &Die, DWARFContext &DCtx) {
-  Optional<DWARFFormValue> Location = Die.findRecursively(DW_AT_location);
-  if (!Location)
-    return false;
-
-  auto ContainsInterestingOperators = [&](StringRef D) {
-    DWARFUnit *U = Die.getDwarfUnit();
-    DataExtractor Data(D, DCtx.isLittleEndian(), U->getAddressByteSize());
-    DWARFExpression Expression(Data, U->getVersion(), U->getAddressByteSize());
-    return any_of(Expression, [](DWARFExpression::Operation &Op) {
-      return !Op.isError() && (Op.getCode() == DW_OP_addr ||
-                               Op.getCode() == DW_OP_form_tls_address ||
-                               Op.getCode() == DW_OP_GNU_push_tls_address);
-    });
-  };
-
-  if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
-    // Inlined location.
-    if (ContainsInterestingOperators(toStringRef(*Expr)))
-      return true;
-  } else if (Optional<uint64_t> Offset = Location->getAsSectionOffset()) {
-    // Location list.
-    if (const DWARFDebugLoc *DebugLoc = DCtx.getDebugLoc()) {
-      if (const DWARFDebugLoc::LocationList *LocList =
-              DebugLoc->getLocationListAtOffset(*Offset)) {
-        if (any_of(LocList->Entries, [&](const DWARFDebugLoc::Entry &E) {
-              return ContainsInterestingOperators({E.Loc.data(), E.Loc.size()});
-            }))
-          return true;
-      }
-    }
-  }
-  return false;
-}
-
-unsigned DWARFVerifier::verifyNameIndexCompleteness(
-    const DWARFDie &Die, const DWARFDebugNames::NameIndex &NI) {
-
-  // First check, if the Die should be indexed. The code follows the DWARF v5
-  // wording as closely as possible.
-
-  // "All non-defining declarations (that is, debugging information entries
-  // with a DW_AT_declaration attribute) are excluded."
-  if (Die.find(DW_AT_declaration))
-    return 0;
-
-  // "DW_TAG_namespace debugging information entries without a DW_AT_name
-  // attribute are included with the name “(anonymous namespace)”.
-  // All other debugging information entries without a DW_AT_name attribute
-  // are excluded."
-  // "If a subprogram or inlined subroutine is included, and has a
-  // DW_AT_linkage_name attribute, there will be an additional index entry for
-  // the linkage name."
-  auto EntryNames = getNames(Die);
-  if (EntryNames.empty())
-    return 0;
-
-  // We deviate from the specification here, which says:
-  // "The name index must contain an entry for each debugging information entry
-  // that defines a named subprogram, label, variable, type, or namespace,
-  // subject to ..."
-  // Instead whitelisting all TAGs representing a "type" or a "subprogram", to
-  // make sure we catch any missing items, we instead blacklist all TAGs that we
-  // know shouldn't be indexed.
-  switch (Die.getTag()) {
-  // Compile unit has a name but it shouldn't be indexed.
-  case DW_TAG_compile_unit:
-    return 0;
-
-  // Function and template parameters are not globally visible, so we shouldn't
-  // index them.
-  case DW_TAG_formal_parameter:
-  case DW_TAG_template_value_parameter:
-  case DW_TAG_template_type_parameter:
-  case DW_TAG_GNU_template_parameter_pack:
-  case DW_TAG_GNU_template_template_param:
-    return 0;
-
-  // Object members aren't globally visible.
-  case DW_TAG_member:
-    return 0;
-
-  // According to a strict reading of the specification, enumerators should not
-  // be indexed (and LLVM currently does not do that). However, this causes
-  // problems for the debuggers, so we may need to reconsider this.
-  case DW_TAG_enumerator:
-    return 0;
-
-  // Imported declarations should not be indexed according to the specification
-  // and LLVM currently does not do that.
-  case DW_TAG_imported_declaration:
-    return 0;
-
-  // "DW_TAG_subprogram, DW_TAG_inlined_subroutine, and DW_TAG_label debugging
-  // information entries without an address attribute (DW_AT_low_pc,
-  // DW_AT_high_pc, DW_AT_ranges, or DW_AT_entry_pc) are excluded."
-  case DW_TAG_subprogram:
-  case DW_TAG_inlined_subroutine:
-  case DW_TAG_label:
-    if (Die.findRecursively(
-            {DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_entry_pc}))
-      break;
-    return 0;
-
-  // "DW_TAG_variable debugging information entries with a DW_AT_location
-  // attribute that includes a DW_OP_addr or DW_OP_form_tls_address operator are
-  // included; otherwise, they are excluded."
-  //
-  // LLVM extension: We also add DW_OP_GNU_push_tls_address to this list.
-  case DW_TAG_variable:
-    if (isVariableIndexable(Die, DCtx))
-      break;
-    return 0;
-
-  default:
-    break;
-  }
-
-  // Now we know that our Die should be present in the Index. Let's check if
-  // that's the case.
-  unsigned NumErrors = 0;
-  for (StringRef Name : EntryNames) {
-    if (none_of(NI.equal_range(Name), [&Die](const DWARFDebugNames::Entry &E) {
-          return E.getDIESectionOffset() == uint64_t(Die.getOffset());
-        })) {
-      error() << formatv("Name Index @ {0:x}: Entry for DIE @ {1:x} ({2}) with "
-                         "name {3} missing.\n",
-                         NI.getUnitOffset(), Die.getOffset(), Die.getTag(),
-                         Name);
-      ++NumErrors;
-    }
-  }
-  return NumErrors;
-}
-
 unsigned DWARFVerifier::verifyDebugNames(const DWARFSection &AccelSection,
                                          const DataExtractor &StrData) {
   unsigned NumErrors = 0;
@@ -1307,16 +1171,6 @@ unsigned DWARFVerifier::verifyDebugNames(const DWARFSection &AccelSection,
     for (uint64_t Name = 1; Name <= NI.getNameCount(); ++Name)
       NumErrors += verifyNameIndexEntries(NI, Name, StrData);
 
-  if (NumErrors > 0)
-    return NumErrors;
-
-  for (const std::unique_ptr<DWARFCompileUnit> &CU : DCtx.compile_units()) {
-    if (const DWARFDebugNames::NameIndex *NI =
-            AccelTable.getCUNameIndex(CU->getOffset())) {
-      for (const DWARFDebugInfoEntry &Die : CU->dies())
-        NumErrors += verifyNameIndexCompleteness(DWARFDie(CU.get(), &Die), *NI);
-    }
-  }
   return NumErrors;
 }