[pdb] Add -type-stats and sort stats by descending size

[rnk]

Summary

It prints this on chromium browser_tests.exe.pdb:

Types
         Total: 5647475 entries ( 371,897,512 bytes,   65.85 avg)
--------------------------------------------------------------------------
      LF_CLASS:  397894 entries ( 119,537,780 bytes,  300.43 avg)
  LF_STRUCTURE:  236351 entries (  83,208,084 bytes,  352.05 avg)
  LF_FIELDLIST:  291003 entries (  66,087,920 bytes,  227.10 avg)
  LF_MFUNCTION: 1884176 entries (  52,756,928 bytes,   28.00 avg)
    LF_POINTER: 1149030 entries (  13,877,344 bytes,   12.08 avg)
    LF_ARGLIST:  789980 entries (  12,436,752 bytes,   15.74 avg)
 LF_METHODLIST:  361498 entries (   8,351,008 bytes,   23.10 avg)
       LF_ENUM:   16069 entries (   6,108,340 bytes,  380.13 avg)
  LF_PROCEDURE:  269374 entries (   4,309,984 bytes,   16.00 avg)
   LF_MODIFIER:  235602 entries (   2,827,224 bytes,   12.00 avg)
      LF_UNION:    9131 entries (   2,072,168 bytes,  226.94 avg)
    LF_VFTABLE:     323 entries (     207,784 bytes,  643.29 avg)
      LF_ARRAY:    6639 entries (     106,380 bytes,   16.02 avg)
    LF_VTSHAPE:     126 entries (       6,472 bytes,   51.37 avg)
   LF_BITFIELD:     278 entries (       3,336 bytes,   12.00 avg)
      LF_LABEL:       1 entries (           8 bytes,    8.00 avg)

The PDB is overall 1.9GB, so the LF_CLASS and LF_STRUCTURE declarations
account for about 10% of the overall file size. I was surprised to find
that on average LF_FIELDLIST records are short. Maybe this is because
there are many more types with short member lists than there are
instantiations with lots of members, like std::vector.

[aganea]

This is what I'm seeing for a large PDB (2 GB). Things are a bit different from your use-case:

                     Type Record Stats
============================================================

  Types
           Total: 7050382 entries ( 536,798,320 bytes,   76.14 avg)
  --------------------------------------------------------------------------
    LF_FIELDLIST:  369709 entries ( 116,277,336 bytes,  314.51 avg)
      LF_VFTABLE:   48428 entries ( 106,221,244 bytes, 2193.38 avg)
    LF_STRUCTURE:  502958 entries (  92,283,348 bytes,  183.48 avg)
    LF_MFUNCTION: 2699622 entries (  75,589,416 bytes,   28.00 avg)
        LF_CLASS:  323609 entries (  72,441,564 bytes,  223.86 avg)
         LF_ENUM:  122798 entries (  24,322,364 bytes,  198.07 avg)
      LF_POINTER: 1262870 entries (  15,468,832 bytes,   12.25 avg)
      LF_ARGLIST:  794482 entries (  12,368,496 bytes,   15.57 avg)
   LF_METHODLIST:  462337 entries (  11,367,124 bytes,   24.59 avg)
        LF_UNION:   29152 entries (   4,260,840 bytes,  146.16 avg)
    LF_PROCEDURE:  236117 entries (   3,777,872 bytes,   16.00 avg)
     LF_MODIFIER:  189660 entries (   2,275,920 bytes,   12.00 avg)
        LF_ARRAY:    7766 entries (     124,912 bytes,   16.08 avg)
      LF_VTSHAPE:     175 entries (      10,668 bytes,   60.96 avg)
     LF_BITFIELD:     698 entries (       8,376 bytes,   12.00 avg)
        LF_LABEL:       1 entries (           8 bytes,    8.00 avg)

llvm/test/DebugInfo/PDB/udt-stats.test

12

Why is <simple type> zero size?

llvm/tools/llvm-pdbutil/DumpOutputStyle.cpp

339

Would you mind increasing {1,7} to {1,8} and {2,8:N} to {2,10:N} please? The output is offsetted on my end:

S_UNAMESPACE:   45458 entries (  904548 bytes)
  S_REGREL32: 4138872 entries (115147908 bytes)
     S_LOCAL: 2487396 entries (57712788 bytes)

702

Rui says no auto in LLD (when the type isn't obvious), is that a policy that should apply everywhere in LLVM?

[rnk]

I happen to know that @zturner is busy from today until next Thursday, so I'm going to go ahead and land this with some tweaks. It's the dumper, so I think post commit review is fine if he has any suggestions for improving this or simplifying the code.

In D59672#1439442, @aganea wrote:

This is what I'm seeing for a large PDB (2 GB). Things are a bit different from your use-case:

                     Type Record Stats
============================================================

  Types
           Total: 7050382 entries ( 536,798,320 bytes,   76.14 avg)
  --------------------------------------------------------------------------
    LF_FIELDLIST:  369709 entries ( 116,277,336 bytes,  314.51 avg)

That's interesting, it's more consistent with what I expected to find. I think this indicates that your codebase has templates with more members, and therefore longer field (and method) lists. I was surprised that the LF_CLASS and LF_STRUCTURE records dominated browser_tests.exe.pdb.

LF_VFTABLE:   48428 entries ( 106,221,244 bytes, 2193.38 avg)

This, is an interesting result. LLVM can't produce these records, only MSVC can. I asked Dave Bartolomeo and YongKang about their purpose, and they told me that they are used for devirtualization at LTCG time. Given that we don't use them, I bet we can just discard them from the PDB by default, with a flag to explicitly request them if desired. These records include long mangled names of all virtual methods, so it adds up.

LF_STRUCTURE:  502958 entries (  92,283,348 bytes,  183.48 avg)
LF_MFUNCTION: 2699622 entries (  75,589,416 bytes,   28.00 avg)

I guess this LF_MFUNCTION result is consistent with long LF_FIELDLISTS: it probably indicates that many classes with many methods are repeatedly instantiated many times with varying parameters across the codebase.

     LF_CLASS:  323609 entries (  72,441,564 bytes,  223.86 avg)
      LF_ENUM:  122798 entries (  24,322,364 bytes,  198.07 avg)
   LF_POINTER: 1262870 entries (  15,468,832 bytes,   12.25 avg)
   LF_ARGLIST:  794482 entries (  12,368,496 bytes,   15.57 avg)
LF_METHODLIST:  462337 entries (  11,367,124 bytes,   24.59 avg)
     LF_UNION:   29152 entries (   4,260,840 bytes,  146.16 avg)
 LF_PROCEDURE:  236117 entries (   3,777,872 bytes,   16.00 avg)
  LF_MODIFIER:  189660 entries (   2,275,920 bytes,   12.00 avg)
     LF_ARRAY:    7766 entries (     124,912 bytes,   16.08 avg)
   LF_VTSHAPE:     175 entries (      10,668 bytes,   60.96 avg)
  LF_BITFIELD:     698 entries (       8,376 bytes,   12.00 avg)
     LF_LABEL:       1 entries (           8 bytes,    8.00 avg)

llvm/test/DebugInfo/PDB/udt-stats.test

12

I think this is the size of the type record being referenced, not the S_UDT record. In the case of simple types, there are no type records. This would correspond to something like typedef void *voidptr_t;.

llvm/tools/llvm-pdbutil/DumpOutputStyle.cpp

339

Definitely, I actually went up to {2,12:N} for types, which is shown down below.

702

Yeah, I'll remove this. @zturner wrote a lot of this code, and I think he has a different attitude towards auto usage.

[aganea]

LGTM other than what I've already commented.

llvm/test/DebugInfo/PDB/module-stats.test

 ; RUN: llvm-pdbutil dump -sym-stats %p/Inputs/empty.pdb | FileCheck --check-prefix=ALL %s
 ; RUN: llvm-pdbutil dump -sym-stats -modi=1 %p/Inputs/empty.pdb | FileCheck --check-prefix=ONE %s
 
 ALL:        Mod 0000 | `d:\src\llvm\test\DebugInfo\PDB\Inputs\empty.obj`:
 ALL-NEXT:     Stream 12, 308 bytes
 ALL:            Symbols
 ALL-NEXT:                                          Total:       6 entries (     204 bytes)
 ALL-NEXT:       --------------------------------------------------------------------------
+ALL-NEXT:                                     S_COMPILE3:       1 entries (      60 bytes)
+ALL-NEXT:                                      S_OBJNAME:       1 entries (      56 bytes)
 ALL-NEXT:                                      S_GPROC32:       1 entries (      44 bytes)
 ALL-NEXT:                                    S_FRAMEPROC:       1 entries (      32 bytes)
-ALL-NEXT:                                          S_END:       1 entries (       4 bytes)
-ALL-NEXT:                                      S_OBJNAME:       1 entries (      56 bytes)
-ALL-NEXT:                                     S_COMPILE3:       1 entries (      60 bytes)
 ALL-NEXT:                                    S_BUILDINFO:       1 entries (       8 bytes)
+ALL-NEXT:                                          S_END:       1 entries (       4 bytes)
 ALL:            Chunks
 ALL-NEXT:                                          Total:       2 entries (      88 bytes)
 ALL-NEXT:       --------------------------------------------------------------------------
-ALL-NEXT:                             DEBUG_S_FILECHKSMS:       1 entries (      32 bytes)
 ALL-NEXT:                                  DEBUG_S_LINES:       1 entries (      56 bytes)
+ALL-NEXT:                             DEBUG_S_FILECHKSMS:       1 entries (      32 bytes)
 ALL-NEXT:   Mod 0001 | `* Linker *`:
 ALL-NEXT:     Stream 14, 520 bytes
 ALL:            Symbols
 ALL-NEXT:                                          Total:      13 entries (     512 bytes)
 ALL-NEXT:       --------------------------------------------------------------------------
-ALL-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
 ALL-NEXT:                                     S_ENVBLOCK:       1 entries (     172 bytes)
+ALL-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
+ALL-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
+ALL-NEXT:                                     S_COMPILE3:       1 entries (      48 bytes)
 ALL-NEXT:                                   S_TRAMPOLINE:       1 entries (      20 bytes)
 ALL-NEXT:                                      S_OBJNAME:       1 entries (      20 bytes)
-ALL-NEXT:                                     S_COMPILE3:       1 entries (      48 bytes)
-ALL-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
 ALL:            Chunks
 ALL-NEXT:                                          Total:       0 entries (       0 bytes)
 ALL-NEXT:       --------------------------------------------------------------------------
 ALL-NEXT:   Summary |
 ALL:            Symbols
 ALL-NEXT:                                          Total:      19 entries (     716 bytes)
 ALL-NEXT:       --------------------------------------------------------------------------
+ALL-NEXT:                                     S_ENVBLOCK:       1 entries (     172 bytes)
+ALL-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
 ALL-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
+ALL-NEXT:                                     S_COMPILE3:       2 entries (     108 bytes)
+ALL-NEXT:                                      S_OBJNAME:       2 entries (      76 bytes)
 ALL-NEXT:                                      S_GPROC32:       1 entries (      44 bytes)
-ALL-NEXT:                                     S_ENVBLOCK:       1 entries (     172 bytes)
 ALL-NEXT:                                    S_FRAMEPROC:       1 entries (      32 bytes)
 ALL-NEXT:                                   S_TRAMPOLINE:       1 entries (      20 bytes)
-ALL-NEXT:                                          S_END:       1 entries (       4 bytes)
-ALL-NEXT:                                      S_OBJNAME:       2 entries (      76 bytes)
-ALL-NEXT:                                     S_COMPILE3:       2 entries (     108 bytes)
-ALL-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
 ALL-NEXT:                                    S_BUILDINFO:       1 entries (       8 bytes)
+ALL-NEXT:                                          S_END:       1 entries (       4 bytes)
 ALL:            Chunks
 ALL-NEXT:                                          Total:       2 entries (      88 bytes)
 ALL-NEXT:       --------------------------------------------------------------------------
-ALL-NEXT:                             DEBUG_S_FILECHKSMS:       1 entries (      32 bytes)
 ALL-NEXT:                                  DEBUG_S_LINES:       1 entries (      56 bytes)
+ALL-NEXT:                             DEBUG_S_FILECHKSMS:       1 entries (      32 bytes)
 
 ONE-NOT:      Mod 0000
 ONE:          Mod 0001 | `* Linker *`:
 ONE-NEXT:     Stream 14, 520 bytes
 ONE:            Symbols
 ONE-NEXT:                                          Total:      13 entries (     512 bytes)
 ONE-NEXT:       --------------------------------------------------------------------------
-ONE-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
 ONE-NEXT:                                     S_ENVBLOCK:       1 entries (     172 bytes)
+ONE-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
+ONE-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
+ONE-NEXT:                                     S_COMPILE3:       1 entries (      48 bytes)
 ONE-NEXT:                                   S_TRAMPOLINE:       1 entries (      20 bytes)
 ONE-NEXT:                                      S_OBJNAME:       1 entries (      20 bytes)
-ONE-NEXT:                                     S_COMPILE3:       1 entries (      48 bytes)
-ONE-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
 ONE:            Chunks
 ONE-NEXT:                                          Total:       0 entries (       0 bytes)
 ONE-NEXT:       --------------------------------------------------------------------------
 ONE-NEXT:   Summary |
 ONE:            Symbols
 ONE-NEXT:                                          Total:      13 entries (     512 bytes)
 ONE-NEXT:       --------------------------------------------------------------------------
-ONE-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
 ONE-NEXT:                                     S_ENVBLOCK:       1 entries (     172 bytes)
+ONE-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
+ONE-NEXT:                                      S_SECTION:       4 entries (     112 bytes)
+ONE-NEXT:                                     S_COMPILE3:       1 entries (      48 bytes)
 ONE-NEXT:                                   S_TRAMPOLINE:       1 entries (      20 bytes)
 ONE-NEXT:                                      S_OBJNAME:       1 entries (      20 bytes)
-ONE-NEXT:                                     S_COMPILE3:       1 entries (      48 bytes)
-ONE-NEXT:                                    S_COFFGROUP:       5 entries (     140 bytes)
 ONE:            Chunks
 ONE-NEXT:                                          Total:       0 entries (       0 bytes)
 ONE-NEXT:       --------------------------------------------------------------------------

llvm/test/DebugInfo/PDB/type-stats.test

+; RUN: llvm-pdbutil dump -type-stats %p/Inputs/empty.pdb | FileCheck --check-prefix=ALL %s
+
+ALL:                           Type Record Stats
+ALL-NEXT: ============================================================
+
+ALL:        Types
+ALL-NEXT:            Total:      75 entries (       5,336 bytes,   71.15 avg)
+ALL-NEXT:   --------------------------------------------------------------------------
+ALL-NEXT:     LF_FIELDLIST:      14 entries (       1,956 bytes,  139.71 avg)
+ALL-NEXT:     LF_STRUCTURE:      14 entries (       1,584 bytes,  113.14 avg)
+ALL-NEXT:          LF_ENUM:       8 entries (         988 bytes,  123.50 avg)
+ALL-NEXT:     LF_MFUNCTION:      14 entries (         392 bytes,   28.00 avg)
+ALL-NEXT:       LF_ARGLIST:      10 entries (         176 bytes,   17.60 avg)
+ALL-NEXT:    LF_METHODLIST:       5 entries (         116 bytes,   23.20 avg)
+ALL-NEXT:       LF_POINTER:       8 entries (          96 bytes,   12.00 avg)
+ALL-NEXT:     LF_PROCEDURE:       1 entries (          16 bytes,   16.00 avg)
+ALL-NEXT:      LF_MODIFIER:       1 entries (          12 bytes,   12.00 avg)

llvm/test/DebugInfo/PDB/udt-stats.test

 ; RUN: llvm-pdbutil dump -udt-stats %p/Inputs/big-read.pdb | FileCheck %s
 
 CHECK:                      S_UDT Record Stats
 CHECK-NEXT: ============================================================
 CHECK:            Record Kind | Count   Size
 CHECK-NEXT:     -----------------------------
-CHECK-NEXT:           LF_ENUM |     3    188
+CHECK-NEXT:      LF_STRUCTURE |    27  1,788
 CHECK-NEXT:        LF_POINTER |    39    468
+CHECK-NEXT:           LF_ENUM |     3    188
 CHECK-NEXT:          LF_UNION |     1     52
-CHECK-NEXT:     <simple type> |    43      0
 CHECK-NEXT:      LF_PROCEDURE |     1     16
-CHECK-NEXT:      LF_STRUCTURE |    27  1,788
+CHECK-NEXT:     <simple type> |    43      0
 CHECK-NEXT:     -----------------------------
 CHECK-NEXT:     Total (S_UDT) |   114  2,604
 CHECK-NEXT:     -----------------------------

llvm/tools/llvm-pdbutil/DumpOutputStyle.h

struct Stat {
     uint32_t Size = 0;
 
     void update(uint32_t RecordSize) {
       ++Count;
       Size += RecordSize;
     }
   };
 
+  using KindAndStat = std::pair<uint32_t, Stat>;
+
   void update(uint32_t Kind, uint32_t RecordSize) {
     Totals.update(RecordSize);
     auto Iter = Individual.try_emplace(Kind, 1, RecordSize);
     if (!Iter.second)
       Iter.first->second.update(RecordSize);
   }
   Stat Totals;
   DenseMap<uint32_t, Stat> Individual;
+
+  std::vector<KindAndStat> getStatsSortedBySize() const;
 };
 
 class DumpOutputStyle : public OutputStyle {
 
 public:
   DumpOutputStyle(InputFile &File);
   ~DumpOutputStyle() override;
 
   Error dump() override;
 
 private:
   PDBFile &getPdb();
   object::COFFObjectFile &getObj();
 
   void printStreamNotValidForObj();
   void printStreamNotPresent(StringRef StreamName);
 
   Error dumpFileSummary();
   Error dumpStreamSummary();
   Error dumpSymbolStats();
   Error dumpUdtStats();
+  Error dumpTypeStats();
   Error dumpNamedStreams();
   Error dumpStringTable();
   Error dumpStringTableFromPdb();
   Error dumpStringTableFromObj();
   Error dumpLines();
   Error dumpInlineeLines();
   Error dumpXmi();
   Error dumpXme();

llvm/tools/llvm-pdbutil/DumpOutputStyle.cpp

Error DumpOutputStyle::dump() {
   }
 
   if (opts::dump::DumpUdtStats) {
     if (auto EC = dumpUdtStats())
       return EC;
     P.NewLine();
   }
 
+  if (opts::dump::DumpTypeStats) {
+    if (auto EC = dumpTypeStats())
+      return EC;
+    P.NewLine();
+  }
+
   if (opts::dump::DumpNamedStreams) {
     if (auto EC = dumpNamedStreams())
       return EC;
     P.NewLine();
   }
 
   if (opts::dump::DumpStringTable || opts::dump::DumpStringTableDetails) {
     if (auto EC = dumpStringTable())

 static inline std::string formatModuleDetailKind(DebugSubsectionKind K) {
   return formatChunkKind(K, false);
 }
 
 static inline std::string formatModuleDetailKind(SymbolKind K) {
   return formatSymbolKind(K);
 }
 
+// Get the stats sorted by size, descending.
+std::vector<StatCollection::KindAndStat>
+StatCollection::getStatsSortedBySize() const {
+  std::vector<KindAndStat> SortedStats(Individual.begin(), Individual.end());
+  std::stable_sort(SortedStats.begin(), SortedStats.end(),
+                   [](const KindAndStat &LHS, const KindAndStat &RHS) {
+                     return LHS.second.Size > RHS.second.Size;
+                   });
+  return SortedStats;
+}
+
 template <typename Kind>
 static void printModuleDetailStats(LinePrinter &P, StringRef Label,
                                    const StatCollection &Stats) {
   P.NewLine();
   P.formatLine("  {0}", Label);
   AutoIndent Indent(P);
   P.formatLine("{0,40}: {1,7} entries ({2,8} bytes)", "Total",
                Stats.Totals.Count, Stats.Totals.Size);
   P.formatLine("{0}", fmt_repeat('-', 74));
-  for (const auto &K : Stats.Individual) {
+
+  for (const auto &K : Stats.getStatsSortedBySize()) {
     std::string KindName = formatModuleDetailKind(Kind(K.first));
-    P.formatLine("{0,40}: {1,7} entries ({2,8} bytes)", KindName,
+    P.formatLine("{0,40}: {1,7} entries ({2,8:N} bytes)", KindName,
                  K.second.Count, K.second.Size);
   }
 }
 
 static bool isMyCode(const SymbolGroup &Group) {
   if (Group.getFile().isObj())
     return true;
 
if (SymStats.Totals.Count > 0) {
     AutoIndent Indent(P, 4);
     printModuleDetailStats<SymbolKind>(P, "Symbols", SymStats);
     printModuleDetailStats<DebugSubsectionKind>(P, "Chunks", ChunkStats);
   }
 
   return Error::success();
 }
 
+Error DumpOutputStyle::dumpTypeStats() {
+  printHeader(P, "Type Record Stats");
+
+  // Iterate the types, categorize by kind, accumulate size stats.
+  StatCollection TypeStats;
+  auto &Types = File.types();
+  for (Optional<TypeIndex> TI = Types.getFirst(); TI; TI = Types.getNext(*TI)) {
+    CVType Type = Types.getType(*TI);
+    TypeStats.update(uint32_t(Type.kind()), Type.length());
+  }
+
+  P.NewLine();
+  P.formatLine("  Types");
+  AutoIndent Indent(P);
+  P.formatLine("{0,14}: {1,7} entries ({2,12:N} bytes, {3,7} avg)", "Total",
+               TypeStats.Totals.Count, TypeStats.Totals.Size,
+               (double)TypeStats.Totals.Size / TypeStats.Totals.Count);
+  P.formatLine("{0}", fmt_repeat('-', 74));
+
+  for (const auto &K : TypeStats.getStatsSortedBySize()) {
+    P.formatLine("{0,14}: {1,7} entries ({2,12:N} bytes, {3,7} avg)",
+                 formatTypeLeafKind(TypeLeafKind(K.first)), K.second.Count,
+                 K.second.Size, (double)K.second.Size / K.second.Count);
+  }
+
+
+  return Error::success();
+}
+
 static bool isValidNamespaceIdentifier(StringRef S) {
   if (S.empty())
     return false;
 
   if (std::isdigit(S[0]))
     return false;
 
   return llvm::all_of(S, [](char C) { return std::isalnum(C); });
Error DumpOutputStyle::dumpUdtStats() {
   uint32_t TableWidth = FieldWidth + 3 + CD + 2 + SD + 1;
 
   P.formatLine("{0} | {1}  {2}",
                fmt_align("Record Kind", AlignStyle::Right, FieldWidth),
                fmt_align(CountHeader, AlignStyle::Right, CD),
                fmt_align(SizeHeader, AlignStyle::Right, SD));
 
   P.formatLine("{0}", fmt_repeat('-', TableWidth));
-  for (const auto &Stat : UdtTargetStats.Individual) {
+  for (const auto &Stat : UdtTargetStats.getStatsSortedBySize()) {
     StringRef Label = getUdtStatLabel(Stat.first);
     P.formatLine("{0} | {1:N}  {2:N}",
                  fmt_align(Label, AlignStyle::Right, FieldWidth),
                  fmt_align(Stat.second.Count, AlignStyle::Right, CD),
                  fmt_align(Stat.second.Size, AlignStyle::Right, SD));
   }
   P.formatLine("{0}", fmt_repeat('-', TableWidth));
   P.formatLine("{0} | {1:N}  {2:N}",
                fmt_align("Total (S_UDT)", AlignStyle::Right, FieldWidth),
                fmt_align(UdtStats.Totals.Count, AlignStyle::Right, CD),
                fmt_align(UdtStats.Totals.Size, AlignStyle::Right, SD));
   P.formatLine("{0}", fmt_repeat('-', TableWidth));
-  for (const auto &Stat : NamespacedStats) {
-    std::string Label = formatv("namespace '{0}'", Stat.getKey());
+  struct StrAndStat {
+    StringRef Key;
+    StatCollection::Stat Stat;
+  };
+
+  // Print namespace stats in descending order of size.
+  std::vector<StrAndStat> NamespacedStatsSorted;
+  for (const auto &Stat : NamespacedStats)
+    NamespacedStatsSorted.push_back({Stat.getKey(), Stat.second});
+  std::stable_sort(NamespacedStatsSorted.begin(), NamespacedStatsSorted.end(),
+                   [](const StrAndStat &L, const StrAndStat &R) {
+                     return L.Stat.Size > R.Stat.Size;
+                   });
+  for (const auto &Stat : NamespacedStatsSorted) {
+    std::string Label = formatv("namespace '{0}'", Stat.Key);
     P.formatLine("{0} | {1:N}  {2:N}",
                  fmt_align(Label, AlignStyle::Right, FieldWidth),
-                 fmt_align(Stat.second.Count, AlignStyle::Right, CD),
-                 fmt_align(Stat.second.Size, AlignStyle::Right, SD));
+                 fmt_align(Stat.Stat.Count, AlignStyle::Right, CD),
+                 fmt_align(Stat.Stat.Size, AlignStyle::Right, SD));
   }
   return Error::success();
 }
 
 static void typesetLinesAndColumns(LinePrinter &P, uint32_t Start,
                                    const LineColumnEntry &E) {
   const uint32_t kMaxCharsPerLineNumber = 4; // 4 digit line number
   uint32_t MinColumnWidth = kMaxCharsPerLineNumber + 5;

llvm/tools/llvm-pdbutil/llvm-pdbutil.h

 } // namespace bytes
 
 namespace dump {
 
 extern llvm::cl::opt<bool> DumpSummary;
 extern llvm::cl::opt<bool> DumpFpm;
 extern llvm::cl::opt<bool> DumpStreams;
 extern llvm::cl::opt<bool> DumpSymbolStats;
+extern llvm::cl::opt<bool> DumpTypeStats;
 extern llvm::cl::opt<bool> DumpUdtStats;
 extern llvm::cl::opt<bool> DumpStreamBlocks;
 
 extern llvm::cl::opt<bool> DumpLines;
 extern llvm::cl::opt<bool> DumpInlineeLines;
 extern llvm::cl::opt<bool> DumpXmi;
 extern llvm::cl::opt<bool> DumpXme;
 extern llvm::cl::opt<bool> DumpNamedStreams;

llvm/tools/llvm-pdbutil/llvm-pdbutil.cpp

 cl::opt<bool> DumpStreamBlocks(
     "stream-blocks",
     cl::desc("Add block information to the output of -streams"),
     cl::cat(MsfOptions), cl::sub(DumpSubcommand));
 cl::opt<bool> DumpSymbolStats(
     "sym-stats",
     cl::desc("Dump a detailed breakdown of symbol usage/size for each module"),
     cl::cat(MsfOptions), cl::sub(DumpSubcommand));
-
+cl::opt<bool> DumpTypeStats(
+    "type-stats",
+    cl::desc("Dump a detailed breakdown of type usage/size"),
+    cl::cat(MsfOptions), cl::sub(DumpSubcommand));
 cl::opt<bool> DumpUdtStats(
     "udt-stats",
     cl::desc("Dump a detailed breakdown of S_UDT record usage / stats"),
     cl::cat(MsfOptions), cl::sub(DumpSubcommand));
 
 // TYPE OPTIONS
 cl::opt<bool> DumpTypes("types",
                         cl::desc("dump CodeView type records from TPI stream"),