1 files changed, 104 insertions, 0 deletions
diff --git a/lib/DebugInfo/PDB/Raw/NameHashTable.cpp b/lib/DebugInfo/PDB/Raw/NameHashTable.cpp
new file mode 100644
index 000000000000..ae4ebf27721e
--- /dev/null
+++ b/lib/DebugInfo/PDB/Raw/NameHashTable.cpp
@@ -0,0 +1,104 @@
+//===- NameHashTable.cpp - PDB Name Hash Table ------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/PDB/Raw/NameHashTable.h"
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/CodeView/StreamReader.h"
+#include "llvm/DebugInfo/PDB/Raw/Hash.h"
+#include "llvm/DebugInfo/PDB/Raw/RawError.h"
+#include "llvm/Support/Endian.h"
+
+using namespace llvm;
+using namespace llvm::support;
+using namespace llvm::pdb;
+
+NameHashTable::NameHashTable() : Signature(0), HashVersion(0), NameCount(0) {}
+
+Error NameHashTable::load(codeview::StreamReader &Stream) {
+  struct Header {
+    support::ulittle32_t Signature;
+    support::ulittle32_t HashVersion;
+    support::ulittle32_t ByteSize;
+  };
+
+  const Header *H;
+  if (auto EC = Stream.readObject(H))
+    return EC;
+
+  if (H->Signature != 0xEFFEEFFE)
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Invalid hash table signature");
+  if (H->HashVersion != 1 && H->HashVersion != 2)
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Unsupported hash version");
+
+  Signature = H->Signature;
+  HashVersion = H->HashVersion;
+  if (auto EC = Stream.readStreamRef(NamesBuffer, H->ByteSize))
+    return joinErrors(std::move(EC),
+                      make_error<RawError>(raw_error_code::corrupt_file,
+                                           "Invalid hash table byte length"));
+
+  const support::ulittle32_t *HashCount;
+  if (auto EC = Stream.readObject(HashCount))
+    return EC;
+
+  if (auto EC = Stream.readArray(IDs, *HashCount))
+    return joinErrors(std::move(EC),
+                      make_error<RawError>(raw_error_code::corrupt_file,
+                                           "Could not read bucket array"));
+
+  if (Stream.bytesRemaining() < sizeof(support::ulittle32_t))
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Missing name count");
+
+  if (auto EC = Stream.readInteger(NameCount))
+    return EC;
+  return Error::success();
+}
+
+StringRef NameHashTable::getStringForID(uint32_t ID) const {
+  if (ID == IDs[0])
+    return StringRef();
+
+  // NamesBuffer is a buffer of null terminated strings back to back.  ID is
+  // the starting offset of the string we're looking for.  So just seek into
+  // the desired offset and a read a null terminated stream from that offset.
+  StringRef Result;
+  codeview::StreamReader NameReader(NamesBuffer);
+  NameReader.setOffset(ID);
+  if (auto EC = NameReader.readZeroString(Result))
+    consumeError(std::move(EC));
+  return Result;
+}
+
+uint32_t NameHashTable::getIDForString(StringRef Str) const {
+  uint32_t Hash = (HashVersion == 1) ? hashStringV1(Str) : hashStringV2(Str);
+  size_t Count = IDs.size();
+  uint32_t Start = Hash % Count;
+  for (size_t I = 0; I < Count; ++I) {
+    // The hash is just a starting point for the search, but if it
+    // doesn't work we should find the string no matter what, because
+    // we iterate the entire array.
+    uint32_t Index = (Start + I) % Count;
+
+    uint32_t ID = IDs[Index];
+    StringRef S = getStringForID(ID);
+    if (S == Str)
+      return ID;
+  }
+  // IDs[0] contains the ID of the "invalid" entry.
+  return IDs[0];
+}
+
+codeview::FixedStreamArray<support::ulittle32_t>
+NameHashTable::name_ids() const {
+  return IDs;
+}