Resubmit "Support embedding natvis files in PDBs."

The issue causing this to fail in certain configurations
should be fixed.

It was due to the fact that DIA apparently expects there to be
a null string at ID 1 in the string table.  I'm not sure why this
is important but it seems to make a difference, so set it.

llvm-svn: 328002

1 files changed, 17 insertions, 8 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
index d723282eb71..c731b68625c 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
@@ -46,12 +46,15 @@ DebugStringTableSubsection::DebugStringTableSubsection()
     : DebugSubsection(DebugSubsectionKind::StringTable) {}
 
 uint32_t DebugStringTableSubsection::insert(StringRef S) {
-  auto P = Strings.insert({S, StringSize});
+  auto P = StringToId.insert({S, StringSize});
 
   // If a given string didn't exist in the string table, we want to increment
-  // the string table size.
-  if (P.second)
+  // the string table size and insert it into the reverse lookup.
+  if (P.second) {
+    IdToString.insert({P.first->getValue(), P.first->getKey()});
     StringSize += S.size() + 1; // +1 for '\0'
+  }
+
   return P.first->second;
 }
 
@@ -67,7 +70,7 @@ Error DebugStringTableSubsection::commit(BinaryStreamWriter &Writer) const {
   if (auto EC = Writer.writeCString(StringRef()))
     return EC;
 
-  for (auto &Pair : Strings) {
+  for (auto &Pair : StringToId) {
     StringRef S = Pair.getKey();
     uint32_t Offset = Begin + Pair.getValue();
     Writer.setOffset(Offset);
@@ -81,10 +84,16 @@ Error DebugStringTableSubsection::commit(BinaryStreamWriter &Writer) const {
   return Error::success();
 }
 
-uint32_t DebugStringTableSubsection::size() const { return Strings.size(); }
+uint32_t DebugStringTableSubsection::size() const { return StringToId.size(); }
+
+uint32_t DebugStringTableSubsection::getIdForString(StringRef S) const {
+  auto Iter = StringToId.find(S);
+  assert(Iter != StringToId.end());
+  return Iter->second;
+}
 
-uint32_t DebugStringTableSubsection::getStringId(StringRef S) const {
-  auto Iter = Strings.find(S);
-  assert(Iter != Strings.end());
+StringRef DebugStringTableSubsection::getStringForId(uint32_t Id) const {
+  auto Iter = IdToString.find(Id);
+  assert(Iter != IdToString.end());
   return Iter->second;
 }