[pdb] Add a pdb2yaml option to not dump file headers.

This will be useful once we start adding the ability to dump type
records and symbol records, since it will allow us to generate
mergeable information instead of information that specifies an
entire file.

llvm-svn: 275109

5 files changed, 39 insertions, 18 deletions

diff --git a/llvm/test/DebugInfo/PDB/pdbdump-yaml.test b/llvm/test/DebugInfo/PDB/pdbdump-yaml.test
index 2d48489e390..3ccc6c25be1 100644
--- a/llvm/test/DebugInfo/PDB/pdbdump-yaml.test
+++ b/llvm/test/DebugInfo/PDB/pdbdump-yaml.test
@@ -1,5 +1,7 @@
 ; RUN: llvm-pdbdump pdb2yaml -stream-metadata -stream-directory -pdb-stream %p/Inputs/empty.pdb \
 ; RUN:   | FileCheck -check-prefix=YAML %s
+; RUN: llvm-pdbdump pdb2yaml -no-file-headers -stream-metadata -stream-directory -pdb-stream \
+; RUN:   %p/Inputs/empty.pdb | FileCheck -check-prefix=NO-HEADERS %s
 
 ; YAML:      ---
 ; YAML-NEXT: MSF:
@@ -74,3 +76,8 @@
 ; YAML-NEXT:   Signature:       1424295906
 ; YAML-NEXT:   Version:         20000404
 ; YAML-NEXT: ...
+
+; NO-HEADERS: ---
+; NO-HEADERS-NOT: MSF:
+; NO-HEADERS-NOT:   SuperBlock:
+; NO-HEADERS: ...
\ No newline at end of file
diff --git a/llvm/tools/llvm-pdbdump/PdbYaml.h b/llvm/tools/llvm-pdbdump/PdbYaml.h
index 96b7d7c8db2..d243f9b12b1 100644
--- a/llvm/tools/llvm-pdbdump/PdbYaml.h
+++ b/llvm/tools/llvm-pdbdump/PdbYaml.h
@@ -46,7 +46,7 @@ struct PdbInfoStream {
 };
 
 struct PdbObject {
-  MsfHeaders Headers;
+  Optional<MsfHeaders> Headers;
   Optional<std::vector<support::ulittle32_t>> StreamSizes;
   Optional<std::vector<StreamBlockList>> StreamMap;
   Optional<PdbInfoStream> PdbStream;
diff --git a/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp b/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp
index 32f19414dd9..f3c730fc6b3 100644
--- a/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp
+++ b/llvm/tools/llvm-pdbdump/YAMLOutputStyle.cpp
@@ -42,20 +42,24 @@ Error YAMLOutputStyle::dump() {
 }
 
 Error YAMLOutputStyle::dumpFileHeaders() {
+  if (opts::pdb2yaml::NoFileHeaders)
+    return Error::success();
+
   yaml::MsfHeaders Headers;
-  Obj.Headers.SuperBlock.NumBlocks = File.getBlockCount();
-  Obj.Headers.SuperBlock.BlockMapAddr = File.getBlockMapIndex();
-  Obj.Headers.BlockMapOffset = File.getBlockMapOffset();
-  Obj.Headers.SuperBlock.BlockSize = File.getBlockSize();
+  Obj.Headers.emplace();
+  Obj.Headers->SuperBlock.NumBlocks = File.getBlockCount();
+  Obj.Headers->SuperBlock.BlockMapAddr = File.getBlockMapIndex();
+  Obj.Headers->BlockMapOffset = File.getBlockMapOffset();
+  Obj.Headers->SuperBlock.BlockSize = File.getBlockSize();
   auto Blocks = File.getDirectoryBlockArray();
-  Obj.Headers.DirectoryBlocks.assign(Blocks.begin(), Blocks.end());
-  Obj.Headers.NumDirectoryBlocks = File.getNumDirectoryBlocks();
-  Obj.Headers.SuperBlock.NumDirectoryBytes = File.getNumDirectoryBytes();
-  Obj.Headers.NumStreams =
+  Obj.Headers->DirectoryBlocks.assign(Blocks.begin(), Blocks.end());
+  Obj.Headers->NumDirectoryBlocks = File.getNumDirectoryBlocks();
+  Obj.Headers->SuperBlock.NumDirectoryBytes = File.getNumDirectoryBytes();
+  Obj.Headers->NumStreams =
       opts::pdb2yaml::StreamMetadata ? File.getNumStreams() : 0;
-  Obj.Headers.SuperBlock.Unknown0 = File.getUnknown0();
-  Obj.Headers.SuperBlock.Unknown1 = File.getUnknown1();
-  Obj.Headers.FileSize = File.getFileSize();
+  Obj.Headers->SuperBlock.Unknown0 = File.getUnknown0();
+  Obj.Headers->SuperBlock.Unknown1 = File.getUnknown1();
+  Obj.Headers->FileSize = File.getFileSize();
 
   return Error::success();
 }
diff --git a/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp b/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp
index 1b72a1927ca..ffb71ba0410 100644
--- a/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp
+++ b/llvm/tools/llvm-pdbdump/llvm-pdbdump.cpp
@@ -261,18 +261,24 @@ cl::list<std::string> InputFilename(cl::Positional,
 }
 
 namespace pdb2yaml {
+cl::opt<bool>
+    NoFileHeaders("no-file-headers",
+                  cl::desc("Do not dump MSF file headers (you will not be able "
+                           "to generate a fresh PDB from the resulting YAML)"),
+                  cl::sub(PdbToYamlSubcommand), cl::init(false));
+
 cl::opt<bool> StreamMetadata(
     "stream-metadata",
     cl::desc("Dump the number of streams and each stream's size"),
-    cl::sub(PdbToYamlSubcommand));
+    cl::sub(PdbToYamlSubcommand), cl::init(false));
 cl::opt<bool> StreamDirectory(
     "stream-directory",
     cl::desc("Dump each stream's block map (implies -stream-metadata)"),
-    cl::sub(PdbToYamlSubcommand));
+    cl::sub(PdbToYamlSubcommand), cl::init(false));
 cl::opt<bool> PdbStream(
     "pdb-stream",
     cl::desc("Dump the PDB Stream (Stream 1) (implies -stream-metadata)"),
-    cl::sub(PdbToYamlSubcommand));
+    cl::sub(PdbToYamlSubcommand), cl::init(false));
 
 cl::list<std::string> InputFilename(cl::Positional,
                                     cl::desc("<input PDB file>"), cl::Required,
@@ -296,9 +302,12 @@ static void yamlToPdb(StringRef Path) {
   llvm::yaml::Input In(Buffer->getBuffer());
   pdb::yaml::PdbObject YamlObj;
   In >> YamlObj;
+  if (!YamlObj.Headers.hasValue())
+    ExitOnErr(make_error<GenericError>(generic_error_code::unspecified,
+                                       "Yaml does not contain MSF headers"));
 
   auto OutFileOrError = FileOutputBuffer::create(
-      opts::yaml2pdb::YamlPdbOutputFile, YamlObj.Headers.FileSize);
+      opts::yaml2pdb::YamlPdbOutputFile, YamlObj.Headers->FileSize);
   if (OutFileOrError.getError())
     ExitOnErr(make_error<GenericError>(generic_error_code::invalid_path,
                                        opts::yaml2pdb::YamlPdbOutputFile));
@@ -306,11 +315,11 @@ static void yamlToPdb(StringRef Path) {
   auto FileByteStream =
       llvm::make_unique<FileBufferByteStream>(std::move(*OutFileOrError));
   PDBFile Pdb(std::move(FileByteStream));
-  ExitOnErr(Pdb.setSuperBlock(&YamlObj.Headers.SuperBlock));
+  ExitOnErr(Pdb.setSuperBlock(&YamlObj.Headers->SuperBlock));
   if (YamlObj.StreamSizes.hasValue()) {
     Pdb.setStreamSizes(YamlObj.StreamSizes.getValue());
   }
-  Pdb.setDirectoryBlocks(YamlObj.Headers.DirectoryBlocks);
+  Pdb.setDirectoryBlocks(YamlObj.Headers->DirectoryBlocks);
 
   if (YamlObj.StreamMap.hasValue()) {
     std::vector<ArrayRef<support::ulittle32_t>> StreamMap;
diff --git a/llvm/tools/llvm-pdbdump/llvm-pdbdump.h b/llvm/tools/llvm-pdbdump/llvm-pdbdump.h
index 412edaaec96..7ccf4d5c2b4 100644
--- a/llvm/tools/llvm-pdbdump/llvm-pdbdump.h
+++ b/llvm/tools/llvm-pdbdump/llvm-pdbdump.h
@@ -57,6 +57,7 @@ extern llvm::cl::opt<bool> DumpFpo;
 }
 
 namespace pdb2yaml {
+extern llvm::cl::opt<bool> NoFileHeaders;
 extern llvm::cl::opt<bool> StreamMetadata;
 extern llvm::cl::opt<bool> StreamDirectory;
 extern llvm::cl::opt<bool> PdbStream;