[codeview] Make obj2yaml/yaml2obj support .debug$S/T sections.

This allows us to use yaml2obj and obj2yaml to round-trip CodeView
symbol and type information without having to manually specify the bytes
of the section. This makes for much easier to maintain tests. See the
tests under lld/COFF in this patch for example. Before they just said
SectionData: <blob> whereas now we can use meaningful record
descriptions. Note that it still supports the SectionData yaml field,
which could be useful for initializing a section to invalid bytes for
testing, for example.

Differential Revision: https://reviews.llvm.org/D34127

llvm-svn: 305366

7 files changed, 65 insertions, 37 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/CMakeLists.txt b/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
index 2f9e8981b69..f916695a843 100644
--- a/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
+++ b/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
@@ -20,6 +20,7 @@ add_llvm_library(LLVMDebugInfoCodeView
   LazyRandomTypeCollection.cpp
   Line.cpp
   RecordSerialization.cpp
+  StringsAndChecksums.cpp
   SymbolRecordMapping.cpp
   SymbolDumper.cpp
   SymbolSerializer.cpp
@@ -32,7 +33,7 @@ add_llvm_library(LLVMDebugInfoCodeView
   TypeSerializer.cpp
   TypeStreamMerger.cpp
   TypeTableCollection.cpp
-  
+
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/DebugInfo/CodeView
   )
diff --git a/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
index 6e647c4b976..de02525270c 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugStringTableSubsection.cpp
@@ -58,6 +58,10 @@ Error DebugStringTableSubsection::commit(BinaryStreamWriter &Writer) const {
   uint32_t Begin = Writer.getOffset();
   uint32_t End = Begin + StringSize;
 
+  // Write a null string at the beginning.
+  if (auto EC = Writer.writeCString(StringRef()))
+    return EC;
+
   for (auto &Pair : Strings) {
     StringRef S = Pair.getKey();
     uint32_t Offset = Begin + Pair.getValue();
@@ -68,6 +72,7 @@ Error DebugStringTableSubsection::commit(BinaryStreamWriter &Writer) const {
   }
 
   Writer.setOffset(End);
+  assert((End - Begin) == StringSize);
   return Error::success();
 }
 
diff --git a/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp b/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
index e9124e68fe8..334c5e002bb 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
@@ -50,7 +50,7 @@ DebugSubsectionKind DebugSubsectionRecord::kind() const { return Kind; }
 BinaryStreamRef DebugSubsectionRecord::getRecordData() const { return Data; }
 
 DebugSubsectionRecordBuilder::DebugSubsectionRecordBuilder(
-    std::unique_ptr<DebugSubsection> Subsection, CodeViewContainer Container)
+    std::shared_ptr<DebugSubsection> Subsection, CodeViewContainer Container)
     : Subsection(std::move(Subsection)), Container(Container) {}
 
 uint32_t DebugSubsectionRecordBuilder::calculateSerializedLength() {
diff --git a/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp b/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp
index 8550107741c..9b824333369 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp
@@ -26,40 +26,9 @@
 using namespace llvm;
 using namespace llvm::codeview;
 
-DebugSubsectionState::DebugSubsectionState() {}
-
-DebugSubsectionState::DebugSubsectionState(
-    const DebugStringTableSubsectionRef &Strings)
-    : Strings(&Strings) {}
-
-DebugSubsectionState::DebugSubsectionState(
-    const DebugStringTableSubsectionRef &Strings,
-    const DebugChecksumsSubsectionRef &Checksums)
-    : Strings(&Strings), Checksums(&Checksums) {}
-
-void DebugSubsectionState::initializeStrings(const DebugSubsectionRecord &SR) {
-  assert(SR.kind() == DebugSubsectionKind::StringTable);
-  assert(!Strings && "Found a string table even though we already have one!");
-
-  OwnedStrings = llvm::make_unique<DebugStringTableSubsectionRef>();
-  consumeError(OwnedStrings->initialize(SR.getRecordData()));
-  Strings = OwnedStrings.get();
-}
-
-void DebugSubsectionState::initializeChecksums(
-    const DebugSubsectionRecord &FCR) {
-  assert(FCR.kind() == DebugSubsectionKind::FileChecksums);
-  if (Checksums)
-    return;
-
-  OwnedChecksums = llvm::make_unique<DebugChecksumsSubsectionRef>();
-  consumeError(OwnedChecksums->initialize(FCR.getRecordData()));
-  Checksums = OwnedChecksums.get();
-}
-
-Error llvm::codeview::visitDebugSubsection(const DebugSubsectionRecord &R,
-                                           DebugSubsectionVisitor &V,
-                                           const DebugSubsectionState &State) {
+Error llvm::codeview::visitDebugSubsection(
+    const DebugSubsectionRecord &R, DebugSubsectionVisitor &V,
+    const StringsAndChecksumsRef &State) {
   BinaryStreamReader Reader(R.getRecordData());
   switch (R.kind()) {
   case DebugSubsectionKind::Lines: {
diff --git a/llvm/lib/DebugInfo/CodeView/StringsAndChecksums.cpp b/llvm/lib/DebugInfo/CodeView/StringsAndChecksums.cpp
new file mode 100644
index 00000000000..ccd9aba45ea
--- /dev/null
+++ b/llvm/lib/DebugInfo/CodeView/StringsAndChecksums.cpp
@@ -0,0 +1,48 @@
+//===- StringsAndChecksums.cpp ----------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/CodeView/StringsAndChecksums.h"
+#include "llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugSubsectionRecord.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+StringsAndChecksumsRef::StringsAndChecksumsRef() {}
+
+StringsAndChecksumsRef::StringsAndChecksumsRef(
+    const DebugStringTableSubsectionRef &Strings)
+    : Strings(&Strings) {}
+
+StringsAndChecksumsRef::StringsAndChecksumsRef(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugChecksumsSubsectionRef &Checksums)
+    : Strings(&Strings), Checksums(&Checksums) {}
+
+void StringsAndChecksumsRef::initializeStrings(
+    const DebugSubsectionRecord &SR) {
+  assert(SR.kind() == DebugSubsectionKind::StringTable);
+  assert(!Strings && "Found a string table even though we already have one!");
+
+  OwnedStrings = llvm::make_unique<DebugStringTableSubsectionRef>();
+  consumeError(OwnedStrings->initialize(SR.getRecordData()));
+  Strings = OwnedStrings.get();
+}
+
+void StringsAndChecksumsRef::initializeChecksums(
+    const DebugSubsectionRecord &FCR) {
+  assert(FCR.kind() == DebugSubsectionKind::FileChecksums);
+  if (Checksums)
+    return;
+
+  OwnedChecksums = llvm::make_unique<DebugChecksumsSubsectionRef>();
+  consumeError(OwnedChecksums->initialize(FCR.getRecordData()));
+  Checksums = OwnedChecksums.get();
+}
diff --git a/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
index 396dffaa68b..81a9d3eeec6 100644
--- a/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
@@ -177,7 +177,7 @@ Error DbiModuleDescriptorBuilder::commit(BinaryStreamWriter &ModiWriter,
 }
 
 void DbiModuleDescriptorBuilder::addDebugSubsection(
-    std::unique_ptr<DebugSubsection> Subsection) {
+    std::shared_ptr<DebugSubsection> Subsection) {
   assert(Subsection);
   C13Builders.push_back(llvm::make_unique<DebugSubsectionRecordBuilder>(
       std::move(Subsection), CodeViewContainer::Pdb));
diff --git a/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp
index a472181a489..90acfadd311 100644
--- a/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp
@@ -52,6 +52,11 @@ uint32_t PDBStringTableBuilder::calculateSerializedSize() const {
   return Size;
 }
 
+void PDBStringTableBuilder::setStrings(
+    const codeview::DebugStringTableSubsection &Strings) {
+  this->Strings = Strings;
+}
+
 Error PDBStringTableBuilder::writeHeader(BinaryStreamWriter &Writer) const {
   // Write a header
   PDBStringTableHeader H;