1 files changed, 89 insertions, 8 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/GlobalsStream.cpp b/llvm/lib/DebugInfo/PDB/Native/GlobalsStream.cpp
index d3d28113e8b..1fe35a691c3 100644
--- a/llvm/lib/DebugInfo/PDB/Native/GlobalsStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/GlobalsStream.cpp
@@ -6,9 +6,21 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// The on-disk structores used in this file are based on the reference
+// implementation which is available at
+// https://github.com/Microsoft/microsoft-pdb/blob/master/PDB/dbi/gsi.h
+//
+// When you are reading the reference source code, you'd find the
+// information below useful.
+//
+//  - ppdb1->m_fMinimalDbgInfo seems to be always true.
+//  - SMALLBUCKETS macro is defined.
+//
+//===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/PDB/Native/GlobalsStream.h"
-#include "GSI.h"
+#include "llvm/DebugInfo/PDB/Native/RawError.h"
 #include "llvm/Support/BinaryStreamReader.h"
 #include "llvm/Support/Error.h"
 #include <algorithm>
@@ -24,19 +36,88 @@ GlobalsStream::~GlobalsStream() = default;
 
 Error GlobalsStream::reload() {
   BinaryStreamReader Reader(*Stream);
+  if (auto E = GlobalsTable.read(Reader))
+    return E;
+  return Error::success();
+}
 
-  const GSIHashHeader *HashHdr;
-  if (auto EC = readGSIHashHeader(HashHdr, Reader))
-    return EC;
+static Error checkHashHdrVersion(const GSIHashHeader *HashHdr) {
+  if (HashHdr->VerHdr != GSIHashHeader::HdrVersion)
+    return make_error<RawError>(
+        raw_error_code::feature_unsupported,
+        "Encountered unsupported globals stream version.");
 
-  if (auto EC = readGSIHashRecords(HashRecords, HashHdr, Reader))
+  return Error::success();
+}
+
+static Error readGSIHashHeader(const GSIHashHeader *&HashHdr,
+                               BinaryStreamReader &Reader) {
+  if (Reader.readObject(HashHdr))
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Stream does not contain a GSIHashHeader.");
+
+  if (HashHdr->VerSignature != GSIHashHeader::HdrSignature)
+    return make_error<RawError>(
+        raw_error_code::feature_unsupported,
+        "GSIHashHeader signature (0xffffffff) not found.");
+
+  return Error::success();
+}
+
+static Error readGSIHashRecords(FixedStreamArray<PSHashRecord> &HashRecords,
+                                const GSIHashHeader *HashHdr,
+                                BinaryStreamReader &Reader) {
+  if (auto EC = checkHashHdrVersion(HashHdr))
     return EC;
 
-  if (auto EC = readGSIHashBuckets(HashBuckets, HashBitmap, HashHdr, Reader))
+  // HashHdr->HrSize specifies the number of bytes of PSHashRecords we have.
+  // Verify that we can read them all.
+  if (HashHdr->HrSize % sizeof(PSHashRecord))
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Invalid HR array size.");
+  uint32_t NumHashRecords = HashHdr->HrSize / sizeof(PSHashRecord);
+  if (auto EC = Reader.readArray(HashRecords, NumHashRecords))
+    return joinErrors(std::move(EC),
+                      make_error<RawError>(raw_error_code::corrupt_file,
+                                           "Error reading hash records."));
+
+  return Error::success();
+}
+
+static Error
+readGSIHashBuckets(FixedStreamArray<support::ulittle32_t> &HashBuckets,
+                   ArrayRef<uint8_t> &HashBitmap, const GSIHashHeader *HashHdr,
+                   BinaryStreamReader &Reader) {
+  if (auto EC = checkHashHdrVersion(HashHdr))
     return EC;
-  NumBuckets = HashBuckets.size();
+
+  // Before the actual hash buckets, there is a bitmap of length determined by
+  // IPHR_HASH.
+  size_t BitmapSizeInBits = alignTo(IPHR_HASH + 1, 32);
+  uint32_t NumBitmapEntries = BitmapSizeInBits / 8;
+  if (auto EC = Reader.readBytes(HashBitmap, NumBitmapEntries))
+    return joinErrors(std::move(EC),
+                      make_error<RawError>(raw_error_code::corrupt_file,
+                                           "Could not read a bitmap."));
+  uint32_t NumBuckets = 0;
+  for (uint8_t B : HashBitmap)
+    NumBuckets += countPopulation(B);
+
+  // Hash buckets follow.
+  if (auto EC = Reader.readArray(HashBuckets, NumBuckets))
+    return joinErrors(std::move(EC),
+                      make_error<RawError>(raw_error_code::corrupt_file,
+                                           "Hash buckets corrupted."));
 
   return Error::success();
 }
 
-Error GlobalsStream::commit() { return Error::success(); }
+Error GSIHashTable::read(BinaryStreamReader &Reader) {
+  if (auto EC = readGSIHashHeader(HashHdr, Reader))
+    return EC;
+  if (auto EC = readGSIHashRecords(HashRecords, HashHdr, Reader))
+    return EC;
+  if (auto EC = readGSIHashBuckets(HashBuckets, HashBitmap, HashHdr, Reader))
+    return EC;
+  return Error::success();
+}