[LLDB][PDB] Fix age field in UUID in PDB file.

[zequanwu]

Summary

There are two age fields in a PDB file. One from the PDB Stream and another one
from the DBI stream.

According to https://randomascii.wordpress.com/2011/11/11/source-indexing-is-underused-awesomeness/#comment-34328,
The age in DBI stream is used to against the binary's age. Pdbstr.exe is used
to only increment the age from PDB stream without changing the DBI age. I
also verified this by manually changing the DBI age of a PDB file and let
windbg.exe to load it. It shows the following logs before and after changing:

Before:

SYMSRV:  BYINDEX: 0xA
         c:\symbols*https://msdl.microsoft.com/download/symbols
         nlaapi.pdb
         D72AA69CD5ABE5D28C74FADB17DE3F8C1
SYMSRV:  PATH: c:\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb
SYMSRV:  RESULT: 0x00000000
*** WARNING: Unable to verify checksum for NLAapi.dll
DBGHELP: NLAapi - public symbols
        c:\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb
...

After:

SYMSRV:  BYINDEX: 0xA
         c:\symbols*https://msdl.microsoft.com/download/symbols
         nlaapi.pdb
         D72AA69CD5ABE5D28C74FADB17DE3F8C1
SYMSRV:  PATH: c:\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb
SYMSRV:  RESULT: 0x00000000
DBGHELP: c:\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb - mismatched pdb
SYMSRV:  BYINDEX: 0xB
         c:\symbols*https://chromium-browser-symsrv.commondatastorage.googleapis.com
         nlaapi.pdb
         D72AA69CD5ABE5D28C74FADB17DE3F8C1
SYMSRV:  PATH: c:\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb
SYMSRV:  RESULT: 0x00000000
DBGHELP: c:\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb - mismatched pdb
SYMSRV:  BYINDEX: 0xC
         c:\src\symbols*https://msdl.microsoft.com/download/symbols
         nlaapi.pdb
         D72AA69CD5ABE5D28C74FADB17DE3F8C1
SYMSRV:  PATH: c:\src\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb
SYMSRV:  RESULT: 0x00000000
*** WARNING: Unable to verify checksum for NLAapi.dll
DBGHELP: NLAapi - public symbols
        c:\src\symbols\nlaapi.pdb\D72AA69CD5ABE5D28C74FADB17DE3F8C1\nlaapi.pdb

So, windbg.exe uses the DBI age to detect mismatched pdb, but it still loads
the pdb even if the age mismatched. Probably lldb should do the same and give
some warnings.

This fixes a bug that lldb can't load some windows system pdbs due to mismatched
uuid.

[rnk]

Wow. Well, I'm not going to argue otherwise. :)

lgtm

lldb/source/Plugins/ObjectFile/PDB/ObjectFilePDB.cpp

 
 using namespace lldb;
 using namespace lldb_private;
 using namespace llvm::pdb;
 using namespace llvm::codeview;
 
 LLDB_PLUGIN_DEFINE(ObjectFilePDB)
 
-static UUID GetPDBUUID(InfoStream &IS) {
+static UUID GetPDBUUID(InfoStream &IS, DbiStream &DS) {
   UUID::CvRecordPdb70 debug_info;
   memcpy(&debug_info.Uuid, IS.getGuid().Guid, sizeof(debug_info.Uuid));
-  debug_info.Age = IS.getAge();
+  debug_info.Age = DS.getAge();
   return UUID(debug_info);
 }
 
 char ObjectFilePDB::ID;
 
 void ObjectFilePDB::Initialize() {
   PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                 GetPluginDescriptionStatic(), CreateInstance,
bool ObjectFilePDB::initPDBFile() {
   m_file_up = loadPDBFile(m_file.GetPath(), m_allocator);
   if (!m_file_up)
     return false;
   auto info_stream = m_file_up->getPDBInfoStream();
   if (!info_stream) {
     llvm::consumeError(info_stream.takeError());
     return false;
   }
-  m_uuid = GetPDBUUID(*info_stream);
+  auto dbi_stream = m_file_up->getPDBDbiStream();
+  if (!dbi_stream) {
+    llvm::consumeError(dbi_stream.takeError());
+    return false;
+  }
+  m_uuid = GetPDBUUID(*info_stream, *dbi_stream);
   return true;
 }
 
 ObjectFile *
 ObjectFilePDB::CreateInstance(const ModuleSP &module_sp, DataBufferSP data_sp,
                               offset_t data_offset, const FileSpec *file,
                               offset_t file_offset, offset_t length) {
   auto objfile_up = std::make_unique<ObjectFilePDB>(
size_t ObjectFilePDB::GetModuleSpecifications(
   }
   auto dbi_stream = pdb_file->getPDBDbiStream();
   if (!dbi_stream) {
     llvm::consumeError(dbi_stream.takeError());
     return initial_count;
   }
 
   lldb_private::UUID &uuid = module_spec.GetUUID();
-  uuid = GetPDBUUID(*info_stream);
+  uuid = GetPDBUUID(*info_stream, *dbi_stream);
 
   ArchSpec &module_arch = module_spec.GetArchitecture();
   switch (dbi_stream->getMachineType()) {
   case PDB_Machine::Amd64:
     module_arch.SetTriple("x86_64-pc-windows");
     specs.Append(module_spec);
     break;
   case PDB_Machine::x86:

lldb/test/Shell/ObjectFile/PDB/object.test

 # RUN: llvm-pdbutil yaml2pdb %s -pdb=%t.pdb
 # RUN: lldb-test object-file %t.pdb | FileCheck %s
 
 # CHECK: Plugin name: pdb
 # CHECK: Architecture: x86_64-pc-windows-msvc
-# CHECK: UUID: 61AF583F-29A8-7A6C-4C4C-44205044422E-00000001
+# CHECK: UUID: 61AF583F-29A8-7A6C-4C4C-44205044422E-00000003
 # CHECK: Executable: false
 # CHECK: Stripped: false
 # CHECK: Type: debug info
 # CHECK: Strata: user
 # CHECK: Base VM address: 0xffffffffffffffff
 # CHECK: There are no sections
 
 ---

 PdbStream:
   Age:             1
   Guid:            '{61AF583F-29A8-7A6C-4C4C-44205044422E}'
   Signature:       1062776673
   Features:        [ VC140 ]
   Version:         VC70
 DbiStream:
   VerHeader:       V70
-  Age:             1
+  Age:             3
   BuildNumber:     36363
   PdbDllVersion:   0
   PdbDllRbld:      0
   Flags:           0
   MachineType:     Amd64
   Modules:
     - Module:          '/tmp/pdb.obj'
       ObjFile:         '/tmp/pdb.obj'