[PDB] Emit S_UDT records in LLD.

Previously these were dropped.  We now understand them sufficiently
well to start emitting them.  From the debugger's perspective, this
now enables us to have debug info about typedefs (both global and
function-locally scoped)

Differential Revision: https://reviews.llvm.org/D55228

llvm-svn: 348306

1 files changed, 32 insertions, 7 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/GSIStreamBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/GSIStreamBuilder.cpp
index b40ae8e9007..57da7003da2 100644
--- a/llvm/lib/DebugInfo/PDB/Native/GSIStreamBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/GSIStreamBuilder.cpp
@@ -9,6 +9,7 @@
 
 #include "llvm/DebugInfo/PDB/Native/GSIStreamBuilder.h"
 
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/DebugInfo/CodeView/RecordName.h"
 #include "llvm/DebugInfo/CodeView/SymbolDeserializer.h"
 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
@@ -20,6 +21,7 @@
 #include "llvm/DebugInfo/PDB/Native/Hash.h"
 #include "llvm/Support/BinaryItemStream.h"
 #include "llvm/Support/BinaryStreamWriter.h"
+#include "llvm/Support/xxhash.h"
 #include <algorithm>
 #include <vector>
 
@@ -29,8 +31,27 @@ using namespace llvm::pdb;
 using namespace llvm::codeview;
 
 struct llvm::pdb::GSIHashStreamBuilder {
+  struct UdtDenseMapInfo {
+    static inline CVSymbol getEmptyKey() {
+      static CVSymbol Empty;
+      return Empty;
+    }
+    static inline CVSymbol getTombstoneKey() {
+      static CVSymbol Tombstone(static_cast<SymbolKind>(-1),
+                                ArrayRef<uint8_t>());
+      return Tombstone;
+    }
+    static unsigned getHashValue(const CVSymbol &Val) {
+      return xxHash64(Val.RecordData);
+    }
+    static bool isEqual(const CVSymbol &LHS, const CVSymbol &RHS) {
+      return LHS.RecordData == RHS.RecordData;
+    }
+  };
+
   std::vector<CVSymbol> Records;
   uint32_t StreamIndex;
+  llvm::DenseSet<CVSymbol, UdtDenseMapInfo> UdtHashes;
   std::vector<PSHashRecord> HashRecords;
   std::array<support::ulittle32_t, (IPHR_HASH + 32) / 32> HashBitmap;
   std::vector<support::ulittle32_t> HashBuckets;
@@ -42,10 +63,18 @@ struct llvm::pdb::GSIHashStreamBuilder {
 
   template <typename T> void addSymbol(const T &Symbol, MSFBuilder &Msf) {
     T Copy(Symbol);
-    Records.push_back(SymbolSerializer::writeOneSymbol(Copy, Msf.getAllocator(),
-                                                       CodeViewContainer::Pdb));
+    addSymbol(SymbolSerializer::writeOneSymbol(Copy, Msf.getAllocator(),
+                                               CodeViewContainer::Pdb));
+  }
+  void addSymbol(const CVSymbol &Symbol) {
+    if (Symbol.kind() == S_UDT) {
+      auto Iter = UdtHashes.insert(Symbol);
+      if (!Iter.second)
+        return;
+    }
+
+    Records.push_back(Symbol);
   }
-  void addSymbol(const CVSymbol &Symbol) { Records.push_back(Symbol); }
 };
 
 uint32_t GSIHashStreamBuilder::calculateSerializedLength() const {
@@ -272,10 +301,6 @@ void GSIStreamBuilder::addGlobalSymbol(const ConstantSym &Sym) {
   GSH->addSymbol(Sym, Msf);
 }
 
-void GSIStreamBuilder::addGlobalSymbol(const UDTSym &Sym) {
-  GSH->addSymbol(Sym, Msf);
-}
-
 void GSIStreamBuilder::addGlobalSymbol(const codeview::CVSymbol &Sym) {
   GSH->addSymbol(Sym);
 }