Lazily deserialize Sema::VTableUses. Plus, fix the utterly and

completely broken deserialization mapping code we had for VTableUses,
which would have broken horribly as soon as our local-to-global ID
mapping became interesting.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136371 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 52 insertions, 18 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index ba00944156..5d81205137 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -8935,6 +8935,30 @@ DeclResult Sema::ActOnCXXConditionDeclaration(Scope *S, Declarator &D) {
   return Dcl;
 }
 
+void Sema::LoadExternalVTableUses() {
+  if (!ExternalSource)
+    return;
+  
+  SmallVector<ExternalVTableUse, 4> VTables;
+  ExternalSource->ReadUsedVTables(VTables);
+  SmallVector<VTableUse, 4> NewUses;
+  for (unsigned I = 0, N = VTables.size(); I != N; ++I) {
+    llvm::DenseMap<CXXRecordDecl *, bool>::iterator Pos
+      = VTablesUsed.find(VTables[I].Record);
+    // Even if a definition wasn't required before, it may be required now.
+    if (Pos != VTablesUsed.end()) {
+      if (!Pos->second && VTables[I].DefinitionRequired)
+        Pos->second = true;
+      continue;
+    }
+    
+    VTablesUsed[VTables[I].Record] = VTables[I].DefinitionRequired;
+    NewUses.push_back(VTableUse(VTables[I].Record, VTables[I].Location));
+  }
+  
+  VTableUses.insert(VTableUses.begin(), NewUses.begin(), NewUses.end());
+}
+
 void Sema::MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
                           bool DefinitionRequired) {
   // Ignore any vtable uses in unevaluated operands or for classes that do
@@ -8945,6 +8969,7 @@ void Sema::MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
     return;
 
   // Try to insert this class into the map.
+  LoadExternalVTableUses();
   Class = cast<CXXRecordDecl>(Class->getCanonicalDecl());
   std::pair<llvm::DenseMap<CXXRecordDecl *, bool>::iterator, bool>
     Pos = VTablesUsed.insert(std::make_pair(Class, DefinitionRequired));
@@ -8970,6 +8995,7 @@ void Sema::MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
 }
 
 bool Sema::DefineUsedVTables() {
+  LoadExternalVTableUses();
   if (VTableUses.empty())
     return false;
 
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index ff87c23897..288e50df74 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2310,11 +2310,22 @@ ASTReader::ReadASTBlock(Module &F) {
       break;
 
     case VTABLE_USES:
+      if (Record.size() % 3 != 0) {
+        Error("Invalid VTABLE_USES record");
+        return Failure;
+      }
+        
       // Later tables overwrite earlier ones.
-      // FIXME: Modules will have some trouble with this.
+      // FIXME: Modules will have some trouble with this. This is clearly not
+      // the right way to do this.
       VTableUses.clear();
-      for (unsigned I = 0, N = Record.size(); I != N; ++I)
-        VTableUses.push_back(getGlobalDeclID(F, Record[I]));
+        
+      for (unsigned Idx = 0, N = Record.size(); Idx != N; /* In loop */) {
+        VTableUses.push_back(getGlobalDeclID(F, Record[Idx++]));
+        VTableUses.push_back(
+          ReadSourceLocation(F, Record, Idx).getRawEncoding());
+        VTableUses.push_back(Record[Idx++]);
+      }
       break;
 
     case DYNAMIC_CLASSES:
@@ -4397,19 +4408,6 @@ void ASTReader::InitializeSema(Sema &S) {
     SemaObj->PendingInstantiations.push_back(std::make_pair(D, Loc));
   }
 
-  // If there were any VTable uses, deserialize the information and add it
-  // to Sema's vector and map of VTable uses.
-  if (!VTableUses.empty()) {
-    unsigned Idx = 0;
-    for (unsigned I = 0, N = VTableUses[Idx++]; I != N; ++I) {
-      CXXRecordDecl *Class = cast<CXXRecordDecl>(GetDecl(VTableUses[Idx++]));
-      SourceLocation Loc = ReadSourceLocation(F, VTableUses, Idx);
-      bool DefinitionRequired = VTableUses[Idx++];
-      SemaObj->VTableUses.push_back(std::make_pair(Class, Loc));
-      SemaObj->VTablesUsed[Class] = DefinitionRequired;
-    }
-  }
-
   if (!FPPragmaOptions.empty()) {
     assert(FPPragmaOptions.size() == 1 && "Wrong number of FP_PRAGMA_OPTIONS");
     SemaObj->FPFeatures.fp_contract = FPPragmaOptions[0];
@@ -4644,6 +4642,18 @@ void ASTReader::ReadWeakUndeclaredIdentifiers(
   WeakUndeclaredIdentifiers.clear();
 }
 
+void ASTReader::ReadUsedVTables(SmallVectorImpl<ExternalVTableUse> &VTables) {
+  for (unsigned Idx = 0, N = VTableUses.size(); Idx < N; /* In loop */) {
+    ExternalVTableUse VT;
+    VT.Record = dyn_cast_or_null<CXXRecordDecl>(GetDecl(VTableUses[Idx++]));
+    VT.Location = SourceLocation::getFromRawEncoding(VTableUses[Idx++]);
+    VT.DefinitionRequired = VTableUses[Idx++];
+    VTables.push_back(VT);
+  }
+  
+  VTableUses.clear();
+}
+
 void ASTReader::LoadSelector(Selector Sel) {
   // It would be complicated to avoid reading the methods anyway. So don't.
   ReadMethodPool(Sel);
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index fb29f6970f..e506bba8a2 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -2886,7 +2886,6 @@ void ASTWriter::WriteASTCore(Sema &SemaRef, MemorizeStatCalls *StatCalls,
   // Build a record containing all of the VTable uses information.
   RecordData VTableUses;
   if (!SemaRef.VTableUses.empty()) {
-    VTableUses.push_back(SemaRef.VTableUses.size());
     for (unsigned I = 0, N = SemaRef.VTableUses.size(); I != N; ++I) {
       AddDeclRef(SemaRef.VTableUses[I].first, VTableUses);
       AddSourceLocation(SemaRef.VTableUses[I].second, VTableUses);
@@ -3153,7 +3152,6 @@ void ASTWriter::WriteASTChain(Sema &SemaRef, MemorizeStatCalls *StatCalls,
   // a use is new to this part.
   RecordData VTableUses;
   if (!SemaRef.VTableUses.empty()) {
-    VTableUses.push_back(SemaRef.VTableUses.size());
     for (unsigned I = 0, N = SemaRef.VTableUses.size(); I != N; ++I) {
       AddDeclRef(SemaRef.VTableUses[I].first, VTableUses);
       AddSourceLocation(SemaRef.VTableUses[I].second, VTableUses);