[MachO] Add undefined atoms.

llvm-svn: 200649

lld/lib/ReaderWriter/MachO/File.h

@@ -37,6 +37,18 @@ public:
     addAtom(*atom);
   }
 
+  void addUndefinedAtom(StringRef name, bool copyRefs) {
+    if (copyRefs) {
+      // 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());
+    }
+    SimpleUndefinedAtom *atom =
+        new (_allocator) SimpleUndefinedAtom(*this, name);
+    addAtom(*atom);
+  }
+
 private:
   llvm::BumpPtrAllocator _allocator;
 };

lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp

@@ -98,8 +98,9 @@ normalizedObjectToAtoms(const NormalizedFile &normalizedFile, StringRef path,
     processSymbol(normalizedFile, *file, sym, copyRefs);
   }
 
-  assert(normalizedFile.undefinedSymbols.empty() &&
-         "undefined symbols not supported yet!");
+  for (auto &sym : normalizedFile.undefinedSymbols) {
+    file->addUndefinedAtom(sym.name, copyRefs);
+  }
 
   return std::unique_ptr<File>(std::move(file));
 }

lld/unittests/MachOTests/MachONormalizedFileToAtomsTests.cpp

@@ -23,8 +23,8 @@ using namespace llvm::MachO;
 TEST(ToAtomsTest, empty_obj_x86_64) {
   NormalizedFile f;
   f.arch = lld::MachOLinkingContext::arch_x86_64;
-  ErrorOr<std::unique_ptr<const lld::File>> atom_f = normalizedToAtoms(f, "",
-                                                                       false);
+  ErrorOr<std::unique_ptr<const lld::File>> atom_f =
+      normalizedToAtoms(f, "", false);
   EXPECT_FALSE(!atom_f);
   EXPECT_EQ(0U, (*atom_f)->defined().size());
 }
@@ -51,6 +51,10 @@ TEST(ToAtomsTest, basic_obj_x86_64) {
   barSymbol.sect = 1;
   barSymbol.value = 2;
   f.globalSymbols.push_back(barSymbol);
+  Symbol undefSym;
+  undefSym.name = "_undef";
+  undefSym.type = N_UNDF;
+  f.undefinedSymbols.push_back(undefSym);
   Symbol bazSymbol;
   bazSymbol.name = "_baz";
   bazSymbol.type = N_SECT;
@@ -59,8 +63,8 @@ TEST(ToAtomsTest, basic_obj_x86_64) {
   bazSymbol.value = 3;
   f.localSymbols.push_back(bazSymbol);
 
-  ErrorOr<std::unique_ptr<const lld::File>> atom_f = normalizedToAtoms(f, "",
-                                                                       false);
+  ErrorOr<std::unique_ptr<const lld::File>> atom_f =
+      normalizedToAtoms(f, "", false);
   EXPECT_FALSE(!atom_f);
   const lld::File &file = **atom_f;
   EXPECT_EQ(3U, file.defined().size());
@@ -70,6 +74,7 @@ TEST(ToAtomsTest, basic_obj_x86_64) {
   const lld::DefinedAtom *atom2 = *it;
   ++it;
   const lld::DefinedAtom *atom3 = *it;
+  const lld::UndefinedAtom *atom4 = *file.undefined().begin();
   EXPECT_TRUE(atom1->name().equals("_foo"));
   EXPECT_EQ(2U, atom1->rawContent().size());
   EXPECT_EQ(0x90, atom1->rawContent()[0]);
@@ -85,4 +90,7 @@ TEST(ToAtomsTest, basic_obj_x86_64) {
   EXPECT_EQ(1U, atom3->rawContent().size());
   EXPECT_EQ(0xC4, atom3->rawContent()[0]);
   EXPECT_EQ(lld::Atom::scopeLinkageUnit, atom3->scope());
+
+  EXPECT_TRUE(atom4->name().equals("_undef"));
+  EXPECT_EQ(lld::Atom::definitionUndefined, atom4->definition());
 }