[pdb] Allow zero-copy read support for symbol streams.

This reduces the amount of memory used by llvm-pdbdump by roughly
1/3 of the size of the PDB file.

Differential Revision: http://reviews.llvm.org/D20724
Reviewed By: ruiu

llvm-svn: 271025

5 files changed, 18 insertions, 11 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/SymbolDumper.cpp b/llvm/lib/DebugInfo/CodeView/SymbolDumper.cpp
index 03b711282b4..7d405ec2453 100644
--- a/llvm/lib/DebugInfo/CodeView/SymbolDumper.cpp
+++ b/llvm/lib/DebugInfo/CodeView/SymbolDumper.cpp
@@ -866,7 +866,7 @@ void CVSymbolDumperImpl::visitUnknownSymbol(SymbolKind Kind,
   W.printNumber("Length", uint32_t(Data.size()));
 }
 
-bool CVSymbolDumper::dump(const SymbolIterator::Record &Record) {
+bool CVSymbolDumper::dump(const CVRecord<SymbolKind> &Record) {
   CVSymbolDumperImpl Dumper(CVTD, ObjDelegate.get(), W, PrintRecordBytes);
   Dumper.visitSymbolRecord(Record);
   return !Dumper.hadError();
diff --git a/llvm/lib/DebugInfo/CodeView/TypeDumper.cpp b/llvm/lib/DebugInfo/CodeView/TypeDumper.cpp
index 74cb2d9e9c4..1db1e54f430 100644
--- a/llvm/lib/DebugInfo/CodeView/TypeDumper.cpp
+++ b/llvm/lib/DebugInfo/CodeView/TypeDumper.cpp
@@ -676,7 +676,7 @@ void CVTypeDumper::printTypeIndex(StringRef FieldName, TypeIndex TI) {
     W->printHex(FieldName, TI.getIndex());
 }
 
-bool CVTypeDumper::dump(const TypeIterator::Record &Record) {
+bool CVTypeDumper::dump(const CVRecord<TypeLeafKind> &Record) {
   assert(W && "printer should not be null");
   CVTypeDumperImpl Dumper(*this, *W, PrintRecordBytes);
   Dumper.visitTypeRecord(Record);
diff --git a/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
index 35937574645..1827ab078df 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/DbiStream.cpp
@@ -136,14 +136,12 @@ Error DbiStream::reload() {
     return make_error<RawError>(raw_error_code::corrupt_file,
                                 "DBI type server substream not aligned.");
 
-  if (auto EC =
-          Reader.readStreamRef(ModInfoSubstream, Header->ModiSubstreamSize))
-    return EC;
-
   // Since each ModInfo in the stream is a variable length, we have to iterate
   // them to know how many there actually are.
-  codeview::VarStreamArray ModInfoArray(ModInfoSubstream, ModInfoRecordLength);
-  for (auto Info : ModInfoArray) {
+  codeview::VarStreamArray<ModInfo> ModInfoArray;
+  if (auto EC = Reader.readArray(ModInfoArray, Header->ModiSubstreamSize))
+    return EC;
+  for (auto &Info : ModInfoArray) {
     ModuleInfos.emplace_back(Info);
   }
 
diff --git a/llvm/lib/DebugInfo/PDB/Raw/ModInfo.cpp b/llvm/lib/DebugInfo/PDB/Raw/ModInfo.cpp
index 9ccb7edd696..67dc81da63a 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/ModInfo.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/ModInfo.cpp
@@ -67,6 +67,8 @@ struct ModInfo::FileLayout {
                              // Null terminated Obj File Name
 };
 
+ModInfo::ModInfo() : Layout(nullptr) {}
+
 ModInfo::ModInfo(codeview::StreamRef Stream) : Layout(nullptr) {
   codeview::StreamReader Reader(Stream);
   if (auto EC = Reader.readObject(Layout)) {
diff --git a/llvm/lib/DebugInfo/PDB/Raw/ModStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/ModStream.cpp
index 38d3f2f23e3..404208a6487 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/ModStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/ModStream.cpp
@@ -9,6 +9,7 @@
 
 #include "llvm/DebugInfo/PDB/Raw/ModStream.h"
 
+#include "llvm/DebugInfo/CodeView/RecordIterator.h"
 #include "llvm/DebugInfo/CodeView/StreamReader.h"
 #include "llvm/DebugInfo/PDB/Raw/ModInfo.h"
 #include "llvm/DebugInfo/PDB/Raw/RawError.h"
@@ -32,8 +33,14 @@ Error ModStream::reload() {
     return llvm::make_error<RawError>(raw_error_code::corrupt_file,
                                       "Module has both C11 and C13 line info");
 
-  if (auto EC = SymbolsSubstream.load(Reader, SymbolSize))
+  codeview::StreamRef S;
+
+  uint32_t SymbolSubstreamSig = 0;
+  if (auto EC = Reader.readInteger(SymbolSubstreamSig))
+    return EC;
+  if (auto EC = Reader.readArray(SymbolsSubstream, SymbolSize - 4))
     return EC;
+
   if (auto EC = Reader.readStreamRef(LinesSubstream, C11Size))
     return EC;
   if (auto EC = Reader.readStreamRef(C13LinesSubstream, C13Size))
@@ -51,6 +58,6 @@ Error ModStream::reload() {
   return Error::success();
 }
 
-iterator_range<codeview::SymbolIterator> ModStream::symbols() const {
-  return codeview::makeSymbolRange(SymbolsSubstream.data().slice(4), nullptr);
+iterator_range<codeview::CVSymbolArray::Iterator> ModStream::symbols() const {
+  return llvm::make_range(SymbolsSubstream.begin(), SymbolsSubstream.end());
 }