[TextAPI] TBD Reader/Writer

Add basic infrastructure for reading and writting TBD files (version 1 - 3).

The TextAPI library is not used by anything yet (besides the unit tests). Tool
support will be added in a separate commit.

The TBD format is currently documented in the implementation file (TextStub.cpp).

https://reviews.llvm.org/D53945

Update: This contains changes to fix issues discovered by the bots:
 - add parentheses to silence warnings.
 - rename variables
 - use PlatformType from BinaryFormat
 - Trying if switching from a vector to an array will appeas the bots.
 - Replace the tuple with a struct to work around an explicit constructor bug.
 - This fixes an issue where we were leaking the YAML document if there was a
   parsing error.

Updated the license information in all files.

llvm-svn: 356820
diff --git a/llvm/lib/TextAPI/MachO/TextStubCommon.h b/llvm/lib/TextAPI/MachO/TextStubCommon.h
new file mode 100644
index 0000000..c4dd107
--- /dev/null
+++ b/llvm/lib/TextAPI/MachO/TextStubCommon.h
@@ -0,0 +1,81 @@
+//===- TextStubCommon.h ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines common Text Stub YAML mappings.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TEXTAPI_TEXT_STUB_COMMON_H
+#define LLVM_TEXTAPI_TEXT_STUB_COMMON_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/YAMLTraits.h"
+#include "llvm/TextAPI/MachO/Architecture.h"
+#include "llvm/TextAPI/MachO/ArchitectureSet.h"
+#include "llvm/TextAPI/MachO/InterfaceFile.h"
+#include "llvm/TextAPI/MachO/PackedVersion.h"
+
+using UUID = std::pair<llvm::MachO::Architecture, std::string>;
+
+LLVM_YAML_STRONG_TYPEDEF(llvm::StringRef, FlowStringRef)
+LLVM_YAML_STRONG_TYPEDEF(uint8_t, SwiftVersion)
+LLVM_YAML_IS_FLOW_SEQUENCE_VECTOR(UUID)
+LLVM_YAML_IS_FLOW_SEQUENCE_VECTOR(FlowStringRef)
+
+namespace llvm {
+namespace yaml {
+
+template <> struct ScalarTraits<FlowStringRef> {
+  static void output(const FlowStringRef &, void *, raw_ostream &);
+  static StringRef input(StringRef, void *, FlowStringRef &);
+  static QuotingType mustQuote(StringRef);
+};
+
+template <> struct ScalarEnumerationTraits<MachO::ObjCConstraintType> {
+  static void enumeration(IO &, MachO::ObjCConstraintType &);
+};
+
+template <> struct ScalarTraits<MachO::PlatformKind> {
+  static void output(const MachO::PlatformKind &, void *, raw_ostream &);
+  static StringRef input(StringRef, void *, MachO::PlatformKind &);
+  static QuotingType mustQuote(StringRef);
+};
+
+template <> struct ScalarBitSetTraits<MachO::ArchitectureSet> {
+  static void bitset(IO &, MachO::ArchitectureSet &);
+};
+
+template <> struct ScalarTraits<MachO::Architecture> {
+  static void output(const MachO::Architecture &, void *, raw_ostream &);
+  static StringRef input(StringRef, void *, MachO::Architecture &);
+  static QuotingType mustQuote(StringRef);
+};
+
+template <> struct ScalarTraits<MachO::PackedVersion> {
+  static void output(const MachO::PackedVersion &, void *, raw_ostream &);
+  static StringRef input(StringRef, void *, MachO::PackedVersion &);
+  static QuotingType mustQuote(StringRef);
+};
+
+template <> struct ScalarTraits<SwiftVersion> {
+  static void output(const SwiftVersion &, void *, raw_ostream &);
+  static StringRef input(StringRef, void *, SwiftVersion &);
+  static QuotingType mustQuote(StringRef);
+};
+
+template <> struct ScalarTraits<UUID> {
+  static void output(const UUID &, void *, raw_ostream &);
+  static StringRef input(StringRef, void *, UUID &);
+  static QuotingType mustQuote(StringRef);
+};
+
+} // end namespace yaml.
+} // end namespace llvm.
+
+#endif // LLVM_TEXTAPI_TEXT_STUB_COMMON_H