[PDB] Make our PDBs look more like MS PDBs.

When investigating bugs in PDB generation, the first step is
often to do the same link with link.exe and then compare PDBs.

But comparing PDBs is hard because two completely different byte
sequences can both be correct, so it hampers the investigation when
you also have to spend time figuring out not just which bytes are
different, but also if the difference is meaningful.

This patch fixes a couple of cases related to string table emission,
hash table emission, and the order in which we emit strings that
makes more of our bytes the same as the bytes generated by MS PDBs.

Differential Revision: https://reviews.llvm.org/D44810

llvm-svn: 328348

1 files changed, 47 insertions, 21 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp
index 1cb890ff799..38bba9eb730 100644
--- a/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/PDBFileBuilder.cpp
@@ -80,11 +80,20 @@ GSIStreamBuilder &PDBFileBuilder::getGsiBuilder() {
   return *Gsi;
 }
 
-Error PDBFileBuilder::addNamedStream(StringRef Name, uint32_t Size) {
+Expected<uint32_t> PDBFileBuilder::allocateNamedStream(StringRef Name,
+                                                       uint32_t Size) {
   auto ExpectedStream = Msf->addStream(Size);
-  if (!ExpectedStream)
-    return ExpectedStream.takeError();
-  NamedStreams.set(Name, *ExpectedStream);
+  if (ExpectedStream)
+    NamedStreams.set(Name, *ExpectedStream);
+  return ExpectedStream;
+}
+
+Error PDBFileBuilder::addNamedStream(StringRef Name, StringRef Data) {
+  Expected<uint32_t> ExpectedIndex = allocateNamedStream(Name, Data.size());
+  if (!ExpectedIndex)
+    return ExpectedIndex.takeError();
+  assert(NamedStreamData.count(*ExpectedIndex) == 0);
+  NamedStreamData[*ExpectedIndex] = Data;
   return Error::success();
 }
 
@@ -101,35 +110,41 @@ Expected<msf::MSFLayout> PDBFileBuilder::finalizeMsfLayout() {
 
   uint32_t StringsLen = Strings.calculateSerializedSize();
 
-  if (auto EC = addNamedStream("/names", StringsLen))
-    return std::move(EC);
-  if (auto EC = addNamedStream("/LinkInfo", 0))
-    return std::move(EC);
+  Expected<uint32_t> SN = allocateNamedStream("/LinkInfo", 0);
+  if (!SN)
+    return SN.takeError();
 
-  if (Info) {
-    if (auto EC = Info->finalizeMsfLayout())
-      return std::move(EC);
-  }
-  if (Dbi) {
-    if (auto EC = Dbi->finalizeMsfLayout())
+  if (Gsi) {
+    if (auto EC = Gsi->finalizeMsfLayout())
       return std::move(EC);
+    if (Dbi) {
+      Dbi->setPublicsStreamIndex(Gsi->getPublicsStreamIndex());
+      Dbi->setGlobalsStreamIndex(Gsi->getGlobalsStreamIndex());
+      Dbi->setSymbolRecordStreamIndex(Gsi->getRecordStreamIdx());
+    }
   }
   if (Tpi) {
     if (auto EC = Tpi->finalizeMsfLayout())
       return std::move(EC);
   }
+  if (Dbi) {
+    if (auto EC = Dbi->finalizeMsfLayout())
+      return std::move(EC);
+  }
+  SN = allocateNamedStream("/names", StringsLen);
+  if (!SN)
+    return SN.takeError();
+
   if (Ipi) {
     if (auto EC = Ipi->finalizeMsfLayout())
       return std::move(EC);
   }
-  if (Gsi) {
-    if (auto EC = Gsi->finalizeMsfLayout())
+
+  // Do this last, since it relies on the named stream map being complete, and
+  // that can be updated by previous steps in the finalization.
+  if (Info) {
+    if (auto EC = Info->finalizeMsfLayout())
       return std::move(EC);
-    if (Dbi) {
-      Dbi->setPublicsStreamIndex(Gsi->getPublicsStreamIndex());
-      Dbi->setGlobalsStreamIndex(Gsi->getGlobalsStreamIndex());
-      Dbi->setSymbolRecordStreamIndex(Gsi->getRecordStreamIdx());
-    }
   }
 
   return Msf->build();
@@ -219,6 +234,17 @@ Error PDBFileBuilder::commit(StringRef Filename) {
   if (auto EC = Strings.commit(NSWriter))
     return EC;
 
+  for (const auto &NSE : NamedStreamData) {
+    if (NSE.second.empty())
+      continue;
+
+    auto NS = WritableMappedBlockStream::createIndexedStream(
+        Layout, Buffer, NSE.first, Allocator);
+    BinaryStreamWriter NSW(*NS);
+    if (auto EC = NSW.writeBytes(arrayRefFromStringRef(NSE.second)))
+      return EC;
+  }
+
   if (Info) {
     if (auto EC = Info->commit(Layout, Buffer))
       return EC;