Don't do a full scan of the type stream before processing records.

LazyRandomTypeCollection is designed for random access, and in
order to provide this it lazily indexes ranges of types.  In the
case of types from an object file, there is no partial index
to build off of, so it has to index the full stream up front.
However, merging types only requires sequential access, and when
that is needed, this extra work is simply wasted.  Changing the
algorithm to work on sequential arrays of types rather than
random access type collections eliminates this up front scan.

llvm-svn: 303707

3 files changed, 15 insertions, 16 deletions

diff --git a/lld/COFF/PDB.cpp b/lld/COFF/PDB.cpp
index 2dbc3797c85..a1b0291a512 100644
--- a/lld/COFF/PDB.cpp
+++ b/lld/COFF/PDB.cpp
@@ -117,9 +117,8 @@ static void mergeDebugT(SymbolTable *Symtab, pdb::PDBFileBuilder &Builder,
     Handler.addSearchPath(llvm::sys::path::parent_path(File->getName()));
     if (auto EC = Reader.readArray(Types, Reader.getLength()))
       fatal(EC, "Reader::readArray failed");
-    codeview::LazyRandomTypeCollection TypesAndIds(Types, 100);
     if (auto Err = codeview::mergeTypeAndIdRecords(
-            IDTable, TypeTable, SourceToDest, &Handler, TypesAndIds))
+            IDTable, TypeTable, SourceToDest, &Handler, Types))
       fatal(Err, "codeview::mergeTypeStreams failed");
   }
 
diff --git a/llvm/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h b/llvm/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h
index d914cf2fd9f..3ad2b4e9c92 100644
--- a/llvm/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h
+++ b/llvm/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h
@@ -40,7 +40,7 @@ class TypeTableBuilder;
 /// appropriate error code.
 Error mergeTypeRecords(TypeTableBuilder &Dest,
                        SmallVectorImpl<TypeIndex> &SourceToDest,
-                       TypeServerHandler *Handler, TypeCollection &Types);
+                       TypeServerHandler *Handler, const CVTypeArray &Types);
 
 /// \brief Merge one set of id records into another.  This method assumes
 /// that all records are id records, and there are no Type records present.
@@ -65,7 +65,7 @@ Error mergeTypeRecords(TypeTableBuilder &Dest,
 /// appropriate error code.
 Error mergeIdRecords(TypeTableBuilder &Dest, ArrayRef<TypeIndex> Types,
                      SmallVectorImpl<TypeIndex> &SourceToDest,
-                     TypeCollection &Ids);
+  const CVTypeArray &Ids);
 
 /// \brief Merge a unified set of type and id records, splitting them into
 /// separate output streams.
@@ -89,7 +89,7 @@ Error mergeTypeAndIdRecords(TypeTableBuilder &DestIds,
                             TypeTableBuilder &DestTypes,
                             SmallVectorImpl<TypeIndex> &SourceToDest,
                             TypeServerHandler *Handler,
-                            TypeCollection &IdsAndTypes);
+  const CVTypeArray &IdsAndTypes);
 
 } // end namespace codeview
 } // end namespace llvm
diff --git a/llvm/lib/DebugInfo/CodeView/TypeStreamMerger.cpp b/llvm/lib/DebugInfo/CodeView/TypeStreamMerger.cpp
index 152634056bd..383799bca7e 100644
--- a/llvm/lib/DebugInfo/CodeView/TypeStreamMerger.cpp
+++ b/llvm/lib/DebugInfo/CodeView/TypeStreamMerger.cpp
@@ -81,14 +81,14 @@ public:
   Error visitMemberEnd(CVMemberRecord &Record) override;
 
   Error mergeTypesAndIds(TypeTableBuilder &DestIds, TypeTableBuilder &DestTypes,
-                         TypeCollection &IdsAndTypes);
+    const CVTypeArray &IdsAndTypes);
   Error mergeIdRecords(TypeTableBuilder &Dest,
                        ArrayRef<TypeIndex> TypeSourceToDest,
-                       TypeCollection &Ids);
-  Error mergeTypeRecords(TypeTableBuilder &Dest, TypeCollection &Types);
+    const CVTypeArray &Ids);
+  Error mergeTypeRecords(TypeTableBuilder &Dest, const CVTypeArray &Types);
 
 private:
-  Error doit(TypeCollection &Types);
+  Error doit(const CVTypeArray &Types);
 
   void addMapping(TypeIndex Idx);
 
@@ -497,7 +497,7 @@ Error TypeStreamMerger::visitUnknownType(CVType &Rec) {
 }
 
 Error TypeStreamMerger::mergeTypeRecords(TypeTableBuilder &Dest,
-                                         TypeCollection &Types) {
+  const CVTypeArray &Types) {
   DestTypeStream = &Dest;
 
   return doit(Types);
@@ -505,7 +505,7 @@ Error TypeStreamMerger::mergeTypeRecords(TypeTableBuilder &Dest,
 
 Error TypeStreamMerger::mergeIdRecords(TypeTableBuilder &Dest,
                                        ArrayRef<TypeIndex> TypeSourceToDest,
-                                       TypeCollection &Ids) {
+  const CVTypeArray &Ids) {
   DestIdStream = &Dest;
   TypeLookup = TypeSourceToDest;
 
@@ -514,14 +514,14 @@ Error TypeStreamMerger::mergeIdRecords(TypeTableBuilder &Dest,
 
 Error TypeStreamMerger::mergeTypesAndIds(TypeTableBuilder &DestIds,
                                          TypeTableBuilder &DestTypes,
-                                         TypeCollection &IdsAndTypes) {
+  const CVTypeArray &IdsAndTypes) {
   DestIdStream = &DestIds;
   DestTypeStream = &DestTypes;
 
   return doit(IdsAndTypes);
 }
 
-Error TypeStreamMerger::doit(TypeCollection &Types) {
+Error TypeStreamMerger::doit(const CVTypeArray &Types) {
   LastError = Error::success();
 
   if (auto EC = codeview::visitTypeStream(Types, *this, Handler))
@@ -559,7 +559,7 @@ Error TypeStreamMerger::doit(TypeCollection &Types) {
 Error llvm::codeview::mergeTypeRecords(TypeTableBuilder &Dest,
                                        SmallVectorImpl<TypeIndex> &SourceToDest,
                                        TypeServerHandler *Handler,
-                                       TypeCollection &Types) {
+  const CVTypeArray &Types) {
   TypeStreamMerger M(SourceToDest, Handler);
   return M.mergeTypeRecords(Dest, Types);
 }
@@ -567,7 +567,7 @@ Error llvm::codeview::mergeTypeRecords(TypeTableBuilder &Dest,
 Error llvm::codeview::mergeIdRecords(TypeTableBuilder &Dest,
                                      ArrayRef<TypeIndex> TypeSourceToDest,
                                      SmallVectorImpl<TypeIndex> &SourceToDest,
-                                     TypeCollection &Ids) {
+  const CVTypeArray &Ids) {
   TypeStreamMerger M(SourceToDest, nullptr);
   return M.mergeIdRecords(Dest, TypeSourceToDest, Ids);
 }
@@ -575,7 +575,7 @@ Error llvm::codeview::mergeIdRecords(TypeTableBuilder &Dest,
 Error llvm::codeview::mergeTypeAndIdRecords(
     TypeTableBuilder &DestIds, TypeTableBuilder &DestTypes,
     SmallVectorImpl<TypeIndex> &SourceToDest, TypeServerHandler *Handler,
-    TypeCollection &IdsAndTypes) {
+  const CVTypeArray &IdsAndTypes) {
 
   TypeStreamMerger M(SourceToDest, Handler);
   return M.mergeTypesAndIds(DestIds, DestTypes, IdsAndTypes);