From 4a6f9ee16ea9306347f1bf6192be1e65c3bf307f Mon Sep 17 00:00:00 2001
From: Zachary Turner <zturner@google.com>
Date: Fri, 5 May 2017 22:02:37 +0000
Subject: [PATCH] [CodeView] Reserve TypeDatabase records up front.

Most of the time we know exactly how many type records we
have in a list, and we want to use the visitor to deserialize
them into actual records in a database.  Previously we were
just using push_back() every time without reserving the space
up front in the vector.  This is obviously terrible from a
performance standpoint, and it's not uncommon to have PDB
files with half a million type records, where the performance
degredation was quite noticeable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302302 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/DebugInfo/CodeView/TypeDatabase.h | 2 +-
 lib/CodeGen/AsmPrinter/CodeViewDebug.cpp       | 2 +-
 lib/DebugInfo/CodeView/TypeDatabase.cpp        | 5 +++++
 tools/llvm-pdbdump/Analyze.cpp                 | 2 +-
 tools/llvm-pdbdump/LLVMOutputStyle.cpp         | 6 +++---
 tools/llvm-readobj/COFFDumper.cpp              | 6 +++---
 6 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/include/llvm/DebugInfo/CodeView/TypeDatabase.h b/include/llvm/DebugInfo/CodeView/TypeDatabase.h
index 220de4bf0ee..be7b19e7df0 100644
--- a/include/llvm/DebugInfo/CodeView/TypeDatabase.h
+++ b/include/llvm/DebugInfo/CodeView/TypeDatabase.h
@@ -21,7 +21,7 @@ namespace llvm {
 namespace codeview {
 class TypeDatabase {
 public:
-  TypeDatabase() : TypeNameStorage(Allocator) {}
+  explicit TypeDatabase(uint32_t ExpectedSize);
 
   /// Gets the type index for the next type record.
   TypeIndex getNextTypeIndex() const;
diff --git a/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 28fa7826ad1..87b45c001de 100644
--- a/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -469,7 +469,7 @@ void CodeViewDebug::emitTypeInformation() {
     CommentPrefix += ' ';
   }
 
-  TypeDatabase TypeDB;
+  TypeDatabase TypeDB(TypeTable.records().size());
   CVTypeDumper CVTD(TypeDB);
   TypeTable.ForEachRecord([&](TypeIndex Index, ArrayRef<uint8_t> Record) {
     if (OS.isVerboseAsm()) {
diff --git a/lib/DebugInfo/CodeView/TypeDatabase.cpp b/lib/DebugInfo/CodeView/TypeDatabase.cpp
index efaba4646ff..5b8841041f8 100644
--- a/lib/DebugInfo/CodeView/TypeDatabase.cpp
+++ b/lib/DebugInfo/CodeView/TypeDatabase.cpp
@@ -65,6 +65,11 @@ static const SimpleTypeEntry SimpleTypeNames[] = {
     {"__bool64*", SimpleTypeKind::Boolean64},
 };
 
+TypeDatabase::TypeDatabase(uint32_t ExpectedSize) : TypeNameStorage(Allocator) {
+  CVUDTNames.reserve(ExpectedSize);
+  TypeRecords.reserve(ExpectedSize);
+}
+
 /// Gets the type index for the next type record.
 TypeIndex TypeDatabase::getNextTypeIndex() const {
   return TypeIndex(TypeIndex::FirstNonSimpleIndex + CVUDTNames.size());
diff --git a/tools/llvm-pdbdump/Analyze.cpp b/tools/llvm-pdbdump/Analyze.cpp
index b65dd40d25f..f7d6ec53b03 100644
--- a/tools/llvm-pdbdump/Analyze.cpp
+++ b/tools/llvm-pdbdump/Analyze.cpp
@@ -74,7 +74,7 @@ Error AnalysisStyle::dump() {
   if (!Tpi)
     return Tpi.takeError();
 
-  TypeDatabase TypeDB;
+  TypeDatabase TypeDB(Tpi->getNumTypeRecords());
   TypeDatabaseVisitor DBV(TypeDB);
   TypeDeserializer Deserializer;
   TypeVisitorCallbackPipeline Pipeline;
diff --git a/tools/llvm-pdbdump/LLVMOutputStyle.cpp b/tools/llvm-pdbdump/LLVMOutputStyle.cpp
index ca7efa69939..2dd4ef0fb30 100644
--- a/tools/llvm-pdbdump/LLVMOutputStyle.cpp
+++ b/tools/llvm-pdbdump/LLVMOutputStyle.cpp
@@ -631,7 +631,7 @@ Error LLVMOutputStyle::dumpTpiStream(uint32_t StreamIdx) {
 
   Visitors.push_back(make_unique<TypeDeserializer>());
   if (!StreamDB.hasValue()) {
-    StreamDB.emplace();
+    StreamDB.emplace(Tpi->getNumTypeRecords());
     Visitors.push_back(make_unique<TypeDatabaseVisitor>(*StreamDB));
   }
   // If we're in dump mode, add a dumper with the appropriate detail level.
@@ -722,14 +722,14 @@ Error LLVMOutputStyle::buildTypeDatabase(uint32_t SN) {
   if (DB.hasValue())
     return Error::success();
 
-  DB.emplace();
-
   auto Tpi =
       (SN == StreamTPI) ? File.getPDBTpiStream() : File.getPDBIpiStream();
 
   if (!Tpi)
     return Tpi.takeError();
 
+  DB.emplace(Tpi->getNumTypeRecords());
+
   TypeVisitorCallbackPipeline Pipeline;
   TypeDeserializer Deserializer;
   TypeDatabaseVisitor DBV(*DB);
diff --git a/tools/llvm-readobj/COFFDumper.cpp b/tools/llvm-readobj/COFFDumper.cpp
index 04386875b95..3f4b6c79178 100644
--- a/tools/llvm-readobj/COFFDumper.cpp
+++ b/tools/llvm-readobj/COFFDumper.cpp
@@ -70,7 +70,7 @@ class COFFDumper : public ObjDumper {
 public:
   friend class COFFObjectDumpDelegate;
   COFFDumper(const llvm::object::COFFObjectFile *Obj, ScopedPrinter &Writer)
-      : ObjDumper(Writer), Obj(Obj), Writer(Writer) {}
+      : ObjDumper(Writer), Obj(Obj), Writer(Writer), TypeDB(100) {}
 
   void printFileHeaders() override;
   void printSections() override;
@@ -1553,7 +1553,7 @@ void llvm::dumpCodeViewMergedTypes(ScopedPrinter &Writer,
     TypeBuf.append(Record.begin(), Record.end());
   });
 
-  TypeDatabase TypeDB;
+  TypeDatabase TypeDB(CVTypes.records().size());
   {
     ListScope S(Writer, "MergedTypeStream");
     CVTypeDumper CVTD(TypeDB);
@@ -1574,7 +1574,7 @@ void llvm::dumpCodeViewMergedTypes(ScopedPrinter &Writer,
 
   {
     ListScope S(Writer, "MergedIDStream");
-    TypeDatabase IDDB;
+    TypeDatabase IDDB(IDTable.records().size());
     CVTypeDumper CVTD(IDDB);
     TypeDumpVisitor TDV(TypeDB, &Writer, opts::CodeViewSubsectionBytes);
     TDV.setItemDB(IDDB);
-- 
2.11.0