[mach-o] enable mach-o and native yaml to be intermixed

The main goal of this patch is to allow "mach-o encoded as yaml" and "native
encoded as yaml" documents to be intermixed.  They are distinguished via 
yaml tags at the start of the document.  This will enable all mach-o test cases
to be written using yaml instead of checking in object files.

The Registry was extend to allow yaml tag handlers to be registered.  The
mach-o Reader adds a yaml tag handler for the tag "!mach-o". 

Additionally, this patch fixes some buffer ownership issues.  When parsing
mach-o binaries, the mach-o atoms can have pointers back into the memory 
mapped .o file.  But with yaml encoded mach-o, name and content are ephemeral, 
so a copyRefs parameter was added to cause the mach-o atoms to make their
own copy.  

llvm-svn: 198986

1 files changed, 10 insertions, 1 deletions

diff --git a/lld/lib/ReaderWriter/MachO/File.h b/lld/lib/ReaderWriter/MachO/File.h
index e002a93e4b4..dad5462c098 100644
--- a/lld/lib/ReaderWriter/MachO/File.h
+++ b/lld/lib/ReaderWriter/MachO/File.h
@@ -21,7 +21,16 @@ class MachOFile : public SimpleFile {
 public:
   MachOFile(StringRef path) : SimpleFile(path) {}
 
-  void addDefinedAtom(StringRef name, ArrayRef<uint8_t> content) {
+  void addDefinedAtom(StringRef name, ArrayRef<uint8_t> content, bool cpyRefs) {
+    if (cpyRefs) {
+      // Make a copy of the atom's name and content that is owned by this file.
+      char *s = _allocator.Allocate<char>(name.size());
+      memcpy(s, name.data(), name.size());
+      name = StringRef(s, name.size());
+      uint8_t *bytes = _allocator.Allocate<uint8_t>(content.size());
+      memcpy(bytes, content.data(), content.size());
+      content = llvm::makeArrayRef(bytes, content.size());
+    }
     MachODefinedAtom *atom =
         new (_allocator) MachODefinedAtom(*this, name, content);
     addAtom(*atom);