Support embedding natvis files in PDBs.

Natvis is a debug language supported by Visual Studio for
specifying custom visualizers.  The /NATVIS option is an
undocumented link.exe flag which will take a .natvis file
and "inject" it into the PDB.  This way, you can ship the
debug visualizers for a program along with the PDB, which
is very useful for postmortem debugging.

This is implemented by adding a new "named stream" to the
PDB with a special name of /src/files/<natvis file name>
and simply copying the contents of the xml into this file.

Additionally, we need to emit a single stream named
/src/headerblock which contains a hash table of embedded
files to records describing them.

This patch adds this functionality, including the /NATVIS
option to lld-link.

Differential Revision: https://reviews.llvm.org/D44328

llvm-svn: 327895

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;
 }