[PDB] Check the type server guid when ghashing

[rnk]

Summary

Previously we simply didn't check this. Prereq to make the test suite
pass with ghash enabled by default.

[rnk]

• remove whitespace change

[aganea]

LTGM.

If you're making /DEBUG:GHASH the default, can we switch back to the "classic" merging?

[rnk]

In D102885#2772493, @aganea wrote:

LTGM.

If you're making /DEBUG:GHASH the default, can we switch back to the "classic" merging?

Yep, that's the plan. I was going to spell it /DEBUG:GHASH-, but that's kind of arbitrary. The other obvious option is noghash.

lld/COFF/DebugTypes.cpp

public:
   explicit TypeServerSource(PDBInputFile *f)
       : TpiSource(PDB, nullptr), pdbInputFile(f) {
     if (f->loadErr && *f->loadErr)
       return;
     pdb::PDBFile &file = f->session->getPDBFile();
     auto expectedInfo = file.getPDBInfoStream();
     if (!expectedInfo)
       return;
-    auto it = mappings.emplace(expectedInfo->getGuid(), this);
+    Guid = expectedInfo->getGuid();
+    auto it = mappings.emplace(Guid, this);
     assert(it.second);
     (void)it;
   }
 
   Error mergeDebugT(TypeMerger *m) override;
 
   void loadGHashes() override;
   void remapTpiWithGHashes(GHashState *g) override;
 
   bool isDependency() const override { return true; }
 
   PDBInputFile *pdbInputFile = nullptr;
 
   // TpiSource for IPI stream.
   TypeServerIpiSource *ipiSrc = nullptr;
 
+  // The PDB signature GUID.
+  codeview::GUID Guid;
+
   static std::map<codeview::GUID, TypeServerSource *> mappings;
 };
 
 // Companion to TypeServerSource. Stores the index map for the IPI stream in the
 // PDB. Modeling PDBs with two sources for TPI and IPI helps establish the
 // invariant of one type index space per source.
 class TypeServerIpiSource : public TpiSource {
 public:
if (it != TypeServerSource::mappings.end()) {
     if (!pdb)
       return createFileError(tsPath, errorCodeToError(std::error_code(
                                          ENOENT, std::generic_category())));
     // If an error occurred during loading, throw it now
     if (pdb->loadErr && *pdb->loadErr)
       return createFileError(tsPath, std::move(*pdb->loadErr));
 
     tsSrc = (TypeServerSource *)pdb->debugTypesObj;
+
+    // Just because a file with a matching name was found and it was an actual
+    // PDB file doesn't mean it matches.  For it to match the InfoStream's GUID
+    // must match the GUID specified in the TypeServer2 record.
+    if (tsSrc->Guid != tsId) {
+      return createFileError(tsPath,
+                             make_error<pdb::PDBError>(
+                                 pdb::pdb_error_code::signature_out_of_date));
+    }
   }
   return tsSrc;
 }
 
 Error UseTypeServerSource::mergeDebugT(TypeMerger *m) {
   Expected<TypeServerSource *> tsSrc = getTypeServerSource();
   if (!tsSrc)
     return tsSrc.takeError();
 
   pdb::PDBFile &pdbSession = (*tsSrc)->pdbInputFile->session->getPDBFile();
   auto expectedInfo = pdbSession.getPDBInfoStream();
   if (!expectedInfo)
     return expectedInfo.takeError();
 
-  // Just because a file with a matching name was found and it was an actual
-  // PDB file doesn't mean it matches.  For it to match the InfoStream's GUID
-  // must match the GUID specified in the TypeServer2 record.
-  if (expectedInfo->getGuid() != typeServerDependency.getGuid())
-    return createFileError(
-        typeServerDependency.getName(),
-        make_error<pdb::PDBError>(pdb::pdb_error_code::signature_out_of_date));
-
   // Reuse the type index map of the type server.
   tpiMap = (*tsSrc)->tpiMap;
   ipiMap = (*tsSrc)->ipiMap;
   return Error::success();
 }
 
 static bool equalsPath(StringRef path1, StringRef path2) {
 #if defined(_WIN32)
void TypeServerSource::remapTpiWithGHashes(GHashState *g) {
   }
 }
 
 void UseTypeServerSource::remapTpiWithGHashes(GHashState *g) {
   // No remapping to do with /Zi objects. Simply use the index map from the type
   // server. Errors should have been reported earlier. Symbols from this object
   // will be ignored.
   Expected<TypeServerSource *> maybeTsSrc = getTypeServerSource();
+
   if (!maybeTsSrc) {
     typeMergingError =
         joinErrors(std::move(typeMergingError), maybeTsSrc.takeError());
     return;
   }
+
   TypeServerSource *tsSrc = *maybeTsSrc;
   tpiMap = tsSrc->tpiMap;
   ipiMap = tsSrc->ipiMap;
 }
 
 void PrecompSource::loadGHashes() {
   if (getDebugH(file)) {
     warn("ignoring .debug$H section; pch with ghash is not implemented");

lld/test/COFF/pdb-type-server-invalid-signature.yaml

 
 # Test linking an OBJ with a reference to an out-of-date PDB type server
 # RUN: cd %S/Inputs
 # RUN: yaml2obj %s -o %t.obj
 # RUN: lld-link %t.obj -out:%t.exe -debug -pdb:%t.pdb -nodefaultlib -entry:main 2>&1 | FileCheck %s
+# RUN: lld-link %t.obj -out:%t.exe -debug:ghash -pdb:%t.pdb -nodefaultlib -entry:main 2>&1 | FileCheck %s
 # RUN: cd %S
 
 # CHECK: warning: Cannot use debug info for '{{.*}}.obj'
 # CHECK-NEXT: The signature does not match; the file(s) might be out of date
 
 # Also test linking an OBJ with a reference to *valid* PDB type server
 # RUN: cd %S/Inputs
 # RUN: yaml2obj %S/Inputs/pdb-type-server-valid-signature.yaml -o %t2.obj