Replace SimpleFileWrapper with a function.

SimpleFileWrapper was a class to wrap an existing (possibly non-mutable)
file as a mutable file. We used instances of the class in RoundTrip*
passes, because the passes convert mutable files to non-mutable files,
and we needed to convert them back to mutable.

That feature can be implemented without defining a new class. Generally
speaking, if we can implement a feature without defining a class and
using only public interface of exsiting classes, that's preferred way
to do that. And this is the case.

llvm-svn: 227549

lld/include/lld/Core/Simple.h

@@ -25,6 +25,18 @@
 
 namespace lld {
 
+// Copy all atoms from src to dst. Atom ownership is not transferred.
+inline void copyAtoms(MutableFile *dst, File *src) {
+  for (const DefinedAtom *atom : src->defined())
+    dst->addAtom(*atom);
+  for (const UndefinedAtom *atom : src->undefined())
+    dst->addAtom(*atom);
+  for (const SharedLibraryAtom *atom : src->sharedLibrary())
+    dst->addAtom(*atom);
+  for (const AbsoluteAtom *atom : src->absolute())
+    dst->addAtom(*atom);
+}
+
 class SimpleFile : public MutableFile {
 public:
   SimpleFile(StringRef path) : MutableFile(path) {}
@@ -77,20 +89,6 @@ protected:
   atom_collection_vector<AbsoluteAtom>       _absoluteAtoms;
 };
 
-class SimpleFileWrapper : public SimpleFile {
-public:
-  SimpleFileWrapper(const File &file) : SimpleFile(file.path()) {
-    for (const DefinedAtom *atom : file.defined())
-      _definedAtoms._atoms.push_back(atom);
-    for (const UndefinedAtom *atom : file.undefined())
-      _undefinedAtoms._atoms.push_back(atom);
-    for (const SharedLibraryAtom *atom : file.sharedLibrary())
-      _sharedLibraryAtoms._atoms.push_back(atom);
-    for (const AbsoluteAtom *atom : file.absolute())
-      _absoluteAtoms._atoms.push_back(atom);
-  }
-};
-
 class SimpleReference : public Reference {
 public:
   SimpleReference(Reference::KindNamespace ns, Reference::KindArch arch,

lld/lib/Passes/RoundTripNativePass.cpp

@@ -49,7 +49,7 @@ void RoundTripNativePass::perform(std::unique_ptr<MutableFile> &mergedFile) {
   File *objFile = _nativeFile[0].get();
   if (objFile->parse())
     llvm_unreachable("native reader parse error");
-  mergedFile.reset(new SimpleFileWrapper(*objFile));
-
+  mergedFile.reset(new SimpleFile(objFile->path()));
+  copyAtoms(mergedFile.get(), objFile);
   llvm::sys::fs::remove(tmpNativeFile.str());
 }

lld/lib/Passes/RoundTripYAMLPass.cpp

@@ -49,6 +49,7 @@ void RoundTripYAMLPass::perform(std::unique_ptr<MutableFile> &mergedFile) {
   File *objFile = _yamlFile[0].get();
   if (objFile->parse())
     llvm_unreachable("native reader parse error");
-  mergedFile.reset(new SimpleFileWrapper(*objFile));
+  mergedFile.reset(new SimpleFile(objFile->path()));
+  copyAtoms(mergedFile.get(), objFile);
   llvm::sys::fs::remove(tmpYAMLFile.str());
 }