DWARFAcceleratorTable: Add an iterator-based api for accessing names in the index

Summary:
Back when we were introducing the DWARF v5 name index, there was a
short discussion whether we shouldn't have a nicer api for iterating
over the index. At that time, I did not find it necessary since the
iteration over names was done only from within the index itself (and I
figured the internal implementation can deal with a slightly rough
interface).

However, now I ran into a use for this kind of API in LLDB (for finding
all names matching a regular expression), so it looked like a nice
opportunity to introduce one. To make the API more useful, I've made the
NameTableEntry class a bit smarter: it now stores the string section
reference (so it can return its name) and its position in the name index
(mainly useful for dumping/logging).

I also convert the internal users to use the new API, which also gives
test coverage for the added code.

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D47590

llvm-svn: 333738

1 files changed, 18 insertions, 19 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index 67da9ccaefd..fe44071d9a2 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -920,8 +920,7 @@ DWARFVerifier::verifyNameIndexBuckets(const DWARFDebugNames::NameIndex &NI,
       if (Hash % NI.getBucketCount() != B.Bucket)
         break;
 
-      auto NTE = NI.getNameTableEntry(Idx);
-      const char *Str = StrData.getCStr(&NTE.StringOffset);
+      const char *Str = NI.getNameTableEntry(Idx).getString();
       if (caseFoldingDjbHash(Str) != Hash) {
         error() << formatv("Name Index @ {0:x}: String ({1}) at index {2} "
                            "hashes to {3:x}, but "
@@ -1057,30 +1056,29 @@ static SmallVector<StringRef, 2> getNames(const DWARFDie &DIE) {
   return Result;
 }
 
-unsigned
-DWARFVerifier::verifyNameIndexEntries(const DWARFDebugNames::NameIndex &NI,
-                                      uint32_t Name,
-                                      const DataExtractor &StrData) {
+unsigned DWARFVerifier::verifyNameIndexEntries(
+    const DWARFDebugNames::NameIndex &NI,
+    const DWARFDebugNames::NameTableEntry &NTE) {
   // Verifying type unit indexes not supported.
   if (NI.getLocalTUCount() + NI.getForeignTUCount() > 0)
     return 0;
 
-  DWARFDebugNames::NameTableEntry NTE = NI.getNameTableEntry(Name);
-  const char *CStr = StrData.getCStr(&NTE.StringOffset);
+  const char *CStr = NTE.getString();
   if (!CStr) {
     error() << formatv(
         "Name Index @ {0:x}: Unable to get string associated with name {1}.\n",
-        NI.getUnitOffset(), Name);
+        NI.getUnitOffset(), NTE.getIndex());
     return 1;
   }
   StringRef Str(CStr);
 
   unsigned NumErrors = 0;
   unsigned NumEntries = 0;
-  uint32_t EntryID = NTE.EntryOffset;
-  Expected<DWARFDebugNames::Entry> EntryOr = NI.getEntry(&NTE.EntryOffset);
-  for (; EntryOr; ++NumEntries, EntryID = NTE.EntryOffset,
-                                EntryOr = NI.getEntry(&NTE.EntryOffset)) {
+  uint32_t EntryID = NTE.getEntryOffset();
+  uint32_t NextEntryID = EntryID;
+  Expected<DWARFDebugNames::Entry> EntryOr = NI.getEntry(&NextEntryID);
+  for (; EntryOr; ++NumEntries, EntryID = NextEntryID,
+                                EntryOr = NI.getEntry(&NextEntryID)) {
     uint32_t CUIndex = *EntryOr->getCUIndex();
     if (CUIndex > NI.getCUCount()) {
       error() << formatv("Name Index @ {0:x}: Entry @ {1:x} contains an "
@@ -1129,13 +1127,14 @@ DWARFVerifier::verifyNameIndexEntries(const DWARFDebugNames::NameIndex &NI,
                       return;
                     error() << formatv("Name Index @ {0:x}: Name {1} ({2}) is "
                                        "not associated with any entries.\n",
-                                       NI.getUnitOffset(), Name, Str);
+                                       NI.getUnitOffset(), NTE.getIndex(), Str);
                     ++NumErrors;
                   },
                   [&](const ErrorInfoBase &Info) {
-                    error() << formatv(
-                        "Name Index @ {0:x}: Name {1} ({2}): {3}\n",
-                        NI.getUnitOffset(), Name, Str, Info.message());
+                    error()
+                        << formatv("Name Index @ {0:x}: Name {1} ({2}): {3}\n",
+                                   NI.getUnitOffset(), NTE.getIndex(), Str,
+                                   Info.message());
                     ++NumErrors;
                   });
   return NumErrors;
@@ -1302,8 +1301,8 @@ unsigned DWARFVerifier::verifyDebugNames(const DWARFSection &AccelSection,
   if (NumErrors > 0)
     return NumErrors;
   for (const auto &NI : AccelTable)
-    for (uint64_t Name = 1; Name <= NI.getNameCount(); ++Name)
-      NumErrors += verifyNameIndexEntries(NI, Name, StrData);
+    for (DWARFDebugNames::NameTableEntry NTE : NI)
+      NumErrors += verifyNameIndexEntries(NI, NTE);
 
   if (NumErrors > 0)
     return NumErrors;