[DWARF] Added verification check for tags in accelerator tables. This patch verifies that the atom tag is actually the same with the tag of the DIE that we retrieve from the table.

Differential Revision: https://reviews.llvm.org/D35963

llvm-svn: 309596

2 files changed, 23 insertions, 7 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp b/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
index 9ae7c9a07f7..f17b00e5605 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
@@ -73,6 +73,8 @@ bool DWARFAcceleratorTable::validateForms() {
     DWARFFormValue FormValue(Atom.second);
     switch (Atom.first) {
     case dwarf::DW_ATOM_die_offset:
+    case dwarf::DW_ATOM_die_tag:
+    case dwarf::DW_ATOM_type_flags:
       if ((!FormValue.isFormClass(DWARFFormValue::FC_Constant) &&
            !FormValue.isFormClass(DWARFFormValue::FC_Flag)) ||
           FormValue.getForm() == dwarf::DW_FORM_sdata)
@@ -84,8 +86,10 @@ bool DWARFAcceleratorTable::validateForms() {
   return true;
 }
 
-uint32_t DWARFAcceleratorTable::readAtoms(uint32_t &HashDataOffset) {
+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;
 
   for (auto Atom : getAtomsDesc()) {
     DWARFFormValue FormValue(Atom.second);
@@ -94,11 +98,14 @@ uint32_t DWARFAcceleratorTable::readAtoms(uint32_t &HashDataOffset) {
     case dwarf::DW_ATOM_die_offset:
       DieOffset = *FormValue.getAsUnsignedConstant();
       break;
+    case dwarf::DW_ATOM_die_tag:
+      DieTag = (dwarf::Tag)*FormValue.getAsUnsignedConstant();
+      break;
     default:
       break;
     }
   }
-  return DieOffset;
+  return {DieOffset, DieTag};
 }
 
 LLVM_DUMP_METHOD void DWARFAcceleratorTable::dump(raw_ostream &OS) const {
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index c5dc723d829..577fce93d3c 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -525,15 +525,16 @@ unsigned DWARFVerifier::verifyAccelTable(const DWARFSection *AccelSection,
     uint32_t StrpOffset;
     uint32_t StringOffset;
     uint32_t StringCount = 0;
-    uint32_t DieOffset = dwarf::DW_INVALID_OFFSET;
-
+    unsigned Offset;
+    unsigned Tag;
     while ((StrpOffset = AccelSectionData.getU32(&HashDataOffset)) != 0) {
       const uint32_t NumHashDataObjects =
           AccelSectionData.getU32(&HashDataOffset);
       for (uint32_t HashDataIdx = 0; HashDataIdx < NumHashDataObjects;
            ++HashDataIdx) {
-        DieOffset = AccelTable.readAtoms(HashDataOffset);
-        if (!DCtx.getDIEForOffset(DieOffset)) {
+        std::tie(Offset, Tag) = AccelTable.readAtoms(HashDataOffset);
+        auto Die = DCtx.getDIEForOffset(Offset);
+        if (!Die) {
           const uint32_t BucketIdx =
               NumBuckets ? (Hash % NumBuckets) : UINT32_MAX;
           StringOffset = StrpOffset;
@@ -546,9 +547,17 @@ unsigned DWARFVerifier::verifyAccelTable(const DWARFSection *AccelSection,
               "Str[%u] = 0x%08x "
               "DIE[%d] = 0x%08x is not a valid DIE offset for \"%s\".\n",
               SectionName, BucketIdx, HashIdx, Hash, StringCount, StrpOffset,
-              HashDataIdx, DieOffset, Name);
+              HashDataIdx, Offset, Name);
 
           ++NumErrors;
+          continue;
+        }
+        if ((Tag != dwarf::DW_TAG_null) && (Die.getTag() != Tag)) {
+          OS << "\terror: Tag " << dwarf::TagString(Tag)
+             << " in accelerator table does not match Tag "
+             << dwarf::TagString(Die.getTag()) << " of DIE[" << HashDataIdx
+             << "].\n";
+          ++NumErrors;
         }
       }
       ++StringCount;