[llvm-pdbutil] Dig deeper into the PDB and DBI streams when explaining.

This will show more detail when using `llvm-pdbutil explain` on an
offset in the DBI or PDB streams.  Specifically, it will dig into
individual header fields and substreams to give a more precise
description of what the byte represents.

llvm-svn: 328878

1 files changed, 9 insertions, 13 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/InfoStream.cpp b/llvm/lib/DebugInfo/PDB/Native/InfoStream.cpp
index b4f217abf85..e9ae5a1a193 100644
--- a/llvm/lib/DebugInfo/PDB/Native/InfoStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/InfoStream.cpp
@@ -21,19 +21,18 @@ using namespace llvm::msf;
 using namespace llvm::pdb;
 
 InfoStream::InfoStream(std::unique_ptr<MappedBlockStream> Stream)
-    : Stream(std::move(Stream)) {}
+    : Stream(std::move(Stream)), Header(nullptr) {}
 
 Error InfoStream::reload() {
   BinaryStreamReader Reader(*Stream);
 
-  const InfoStreamHeader *H;
-  if (auto EC = Reader.readObject(H))
+  if (auto EC = Reader.readObject(Header))
     return joinErrors(
         std::move(EC),
         make_error<RawError>(raw_error_code::corrupt_file,
                              "PDB Stream does not contain a header."));
 
-  switch (H->Version) {
+  switch (Header->Version) {
   case PdbImplVC70:
   case PdbImplVC80:
   case PdbImplVC110:
@@ -44,11 +43,6 @@ Error InfoStream::reload() {
                                 "Unsupported PDB stream version.");
   }
 
-  Version = H->Version;
-  Signature = H->Signature;
-  Age = H->Age;
-  Guid = H->Guid;
-
   uint32_t Offset = Reader.getOffset();
   if (auto EC = NamedStreams.load(Reader))
     return EC;
@@ -108,14 +102,16 @@ bool InfoStream::containsIdStream() const {
 }
 
 PdbRaw_ImplVer InfoStream::getVersion() const {
-  return static_cast<PdbRaw_ImplVer>(Version);
+  return static_cast<PdbRaw_ImplVer>(uint32_t(Header->Version));
 }
 
-uint32_t InfoStream::getSignature() const { return Signature; }
+uint32_t InfoStream::getSignature() const {
+  return uint32_t(Header->Signature);
+}
 
-uint32_t InfoStream::getAge() const { return Age; }
+uint32_t InfoStream::getAge() const { return uint32_t(Header->Age); }
 
-GUID InfoStream::getGuid() const { return Guid; }
+GUID InfoStream::getGuid() const { return Header->Guid; }
 
 uint32_t InfoStream::getNamedStreamMapByteSize() const {
   return NamedStreamMapByteSize;